diff options
| author | Linus Torvalds | 2017-09-04 18:52:57 +0200 |
|---|---|---|
| committer | Linus Torvalds | 2017-09-04 18:52:57 +0200 |
| commit | b0c79f49c343cda8954b3322984c32f258ca4ccb (patch) | |
| tree | dd823d13683b7e6b0caebcaf3964df6150aee294 /arch | |
| parent | Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/ker... (diff) | |
| parent | objtool: Handle GCC stack pointer adjustment bug (diff) | |
| download | kernel-qcow2-linux-b0c79f49c343cda8954b3322984c32f258ca4ccb.tar.gz kernel-qcow2-linux-b0c79f49c343cda8954b3322984c32f258ca4ccb.tar.xz kernel-qcow2-linux-b0c79f49c343cda8954b3322984c32f258ca4ccb.zip | |
Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 asm updates from Ingo Molnar:
- Introduce the ORC unwinder, which can be enabled via
CONFIG_ORC_UNWINDER=y.
The ORC unwinder is a lightweight, Linux kernel specific debuginfo
implementation, which aims to be DWARF done right for unwinding.
Objtool is used to generate the ORC unwinder tables during build, so
the data format is flexible and kernel internal: there's no
dependency on debuginfo created by an external toolchain.
The ORC unwinder is almost two orders of magnitude faster than the
(out of tree) DWARF unwinder - which is important for perf call graph
profiling. It is also significantly simpler and is coded defensively:
there has not been a single ORC related kernel crash so far, even
with early versions. (knock on wood!)
But the main advantage is that enabling the ORC unwinder allows
CONFIG_FRAME_POINTERS to be turned off - which speeds up the kernel
measurably:
With frame pointers disabled, GCC does not have to add frame pointer
instrumentation code to every function in the kernel. The kernel's
.text size decreases by about 3.2%, resulting in better cache
utilization and fewer instructions executed, resulting in a broad
kernel-wide speedup. Average speedup of system calls should be
roughly in the 1-3% range - measurements by Mel Gorman [1] have shown
a speedup of 5-10% for some function execution intense workloads.
The main cost of the unwinder is that the unwinder data has to be
stored in RAM: the memory cost is 2-4MB of RAM, depending on kernel
config - which is a modest cost on modern x86 systems.
Given how young the ORC unwinder code is it's not enabled by default
- but given the performance advantages the plan is to eventually make
it the default unwinder on x86.
See Documentation/x86/orc-unwinder.txt for more details.
- Remove lguest support: its intended role was that of a temporary
proof of concept for virtualization, plus its removal will enable the
reduction (removal) of the paravirt API as well, so Rusty agreed to
its removal. (Juergen Gross)
- Clean up and fix FSGS related functionality (Andy Lutomirski)
- Clean up IO access APIs (Andy Shevchenko)
- Enhance the symbol namespace (Jiri Slaby)
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (47 commits)
objtool: Handle GCC stack pointer adjustment bug
x86/entry/64: Use ENTRY() instead of ALIGN+GLOBAL for stub32_clone()
x86/fpu/math-emu: Add ENDPROC to functions
x86/boot/64: Extract efi_pe_entry() from startup_64()
x86/boot/32: Extract efi_pe_entry() from startup_32()
x86/lguest: Remove lguest support
x86/paravirt/xen: Remove xen_patch()
objtool: Fix objtool fallthrough detection with function padding
x86/xen/64: Fix the reported SS and CS in SYSCALL
objtool: Track DRAP separately from callee-saved registers
objtool: Fix validate_branch() return codes
x86: Clarify/fix no-op barriers for text_poke_bp()
x86/switch_to/64: Rewrite FS/GS switching yet again to fix AMD CPUs
selftests/x86/fsgsbase: Test selectors 1, 2, and 3
x86/fsgsbase/64: Report FSBASE and GSBASE correctly in core dumps
x86/fsgsbase/64: Fully initialize FS and GS state in start_thread_common
x86/asm: Fix UNWIND_HINT_REGS macro for older binutils
x86/asm/32: Fix regs_get_register() on segment registers
x86/xen/64: Rearrange the SYSCALL entries
x86/asm/32: Remove a bunch of '& 0xffff' from pt_regs segment reads
...
Diffstat (limited to 'arch')
70 files changed, 1661 insertions, 2565 deletions
diff --git a/arch/um/include/asm/unwind.h b/arch/um/include/asm/unwind.h new file mode 100644 index 000000000000..7ffa5437b761 --- /dev/null +++ b/arch/um/include/asm/unwind.h @@ -0,0 +1,8 @@ +#ifndef _ASM_UML_UNWIND_H +#define _ASM_UML_UNWIND_H + +static inline void +unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size, + void *orc, size_t orc_size) {} + +#endif /* _ASM_UML_UNWIND_H */ diff --git a/arch/x86/Kbuild b/arch/x86/Kbuild index 586b786b3edf..f65a804b86f0 100644 --- a/arch/x86/Kbuild +++ b/arch/x86/Kbuild @@ -10,9 +10,6 @@ obj-$(CONFIG_XEN) += xen/ # Hyper-V paravirtualization support obj-$(CONFIG_HYPERVISOR_GUEST) += hyperv/ -# lguest paravirtualization support -obj-$(CONFIG_LGUEST_GUEST) += lguest/ - obj-y += realmode/ obj-y += kernel/ obj-y += mm/ diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 323cb065be5e..9c95aa417e9b 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -73,7 +73,6 @@ config X86 select ARCH_USE_QUEUED_RWLOCKS select ARCH_USE_QUEUED_SPINLOCKS select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH - select ARCH_WANT_FRAME_POINTERS select ARCH_WANTS_DYNAMIC_TASK_STRUCT select ARCH_WANTS_THP_SWAP if X86_64 select BUILDTIME_EXTABLE_SORT @@ -158,6 +157,7 @@ config X86 select HAVE_MEMBLOCK select HAVE_MEMBLOCK_NODE_MAP select HAVE_MIXED_BREAKPOINTS_REGS + select HAVE_MOD_ARCH_SPECIFIC select HAVE_NMI select HAVE_OPROFILE select HAVE_OPTPROBES @@ -168,7 +168,7 @@ config X86 select HAVE_PERF_REGS select HAVE_PERF_USER_STACK_DUMP select HAVE_REGS_AND_STACK_ACCESS_API - select HAVE_RELIABLE_STACKTRACE if X86_64 && FRAME_POINTER && STACK_VALIDATION + select HAVE_RELIABLE_STACKTRACE if X86_64 && FRAME_POINTER_UNWINDER && STACK_VALIDATION select HAVE_STACK_VALIDATION if X86_64 select HAVE_SYSCALL_TRACEPOINTS select HAVE_UNSTABLE_SCHED_CLOCK @@ -778,8 +778,6 @@ config KVM_DEBUG_FS Statistics are displayed in debugfs filesystem. Enabling this option may incur significant overhead. -source "arch/x86/lguest/Kconfig" - config PARAVIRT_TIME_ACCOUNTING bool "Paravirtual steal time accounting" depends on PARAVIRT diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug index cd20ca0b4043..71a48a30fc84 100644 --- a/arch/x86/Kconfig.debug +++ b/arch/x86/Kconfig.debug @@ -305,8 +305,6 @@ config DEBUG_ENTRY Some of these sanity checks may slow down kernel entries and exits or otherwise impact performance. - This is currently used to help test NMI code. - If unsure, say N. config DEBUG_NMI_SELFTEST @@ -358,4 +356,61 @@ config PUNIT_ATOM_DEBUG The current power state can be read from /sys/kernel/debug/punit_atom/dev_power_state +choice + prompt "Choose kernel unwinder" + default FRAME_POINTER_UNWINDER + ---help--- + This determines which method will be used for unwinding kernel stack + traces for panics, oopses, bugs, warnings, perf, /proc/<pid>/stack, + livepatch, lockdep, and more. + +config FRAME_POINTER_UNWINDER + bool "Frame pointer unwinder" + select FRAME_POINTER + ---help--- + This option enables the frame pointer unwinder for unwinding kernel + stack traces. + + The unwinder itself is fast and it uses less RAM than the ORC + unwinder, but the kernel text size will grow by ~3% and the kernel's + overall performance will degrade by roughly 5-10%. + + This option is recommended if you want to use the livepatch + consistency model, as this is currently the only way to get a + reliable stack trace (CONFIG_HAVE_RELIABLE_STACKTRACE). + +config ORC_UNWINDER + bool "ORC unwinder" + depends on X86_64 + select STACK_VALIDATION + ---help--- + This option enables the ORC (Oops Rewind Capability) unwinder for + unwinding kernel stack traces. It uses a custom data format which is + a simplified version of the DWARF Call Frame Information standard. + + This unwinder is more accurate across interrupt entry frames than the + frame pointer unwinder. It also enables a 5-10% performance + improvement across the entire kernel compared to frame pointers. + + Enabling this option will increase the kernel's runtime memory usage + by roughly 2-4MB, depending on your kernel config. + +config GUESS_UNWINDER + bool "Guess unwinder" + depends on EXPERT + ---help--- + This option enables the "guess" unwinder for unwinding kernel stack + traces. It scans the stack and reports every kernel text address it + finds. Some of the addresses it reports may be incorrect. + + While this option often produces false positives, it can still be + useful in many cases. Unlike the other unwinders, it has no runtime + overhead. + +endchoice + +config FRAME_POINTER + depends on !ORC_UNWINDER && !GUESS_UNWINDER + bool + endmenu diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S index d85b9625e836..11c68cf53d4e 100644 --- a/arch/x86/boot/compressed/head_32.S +++ b/arch/x86/boot/compressed/head_32.S @@ -61,71 +61,6 @@ __HEAD ENTRY(startup_32) -#ifdef CONFIG_EFI_STUB - jmp preferred_addr - - /* - * We don't need the return address, so set up the stack so - * efi_main() can find its arguments. - */ -ENTRY(efi_pe_entry) - add $0x4, %esp - - call 1f -1: popl %esi - subl $1b, %esi - - popl %ecx - movl %ecx, efi32_config(%esi) /* Handle */ - popl %ecx - movl %ecx, efi32_config+8(%esi) /* EFI System table pointer */ - - /* Relocate efi_config->call() */ - leal efi32_config(%esi), %eax - add %esi, 40(%eax) - pushl %eax - - call make_boot_params - cmpl $0, %eax - je fail - movl %esi, BP_code32_start(%eax) - popl %ecx - pushl %eax - pushl %ecx - jmp 2f /* Skip efi_config initialization */ - -ENTRY(efi32_stub_entry) - add $0x4, %esp - popl %ecx - popl %edx - - call 1f -1: popl %esi - subl $1b, %esi - - movl %ecx, efi32_config(%esi) /* Handle */ - movl %edx, efi32_config+8(%esi) /* EFI System table pointer */ - - /* Relocate efi_config->call() */ - leal efi32_config(%esi), %eax - add %esi, 40(%eax) - pushl %eax -2: - call efi_main - cmpl $0, %eax - movl %eax, %esi - jne 2f -fail: - /* EFI init failed, so hang. */ - hlt - jmp fail -2: - movl BP_code32_start(%esi), %eax - leal preferred_addr(%eax), %eax - jmp *%eax - -preferred_addr: -#endif cld /* * Test KEEP_SEGMENTS flag to see if the bootloader is asking @@ -208,6 +143,70 @@ preferred_addr: jmp *%eax ENDPROC(startup_32) +#ifdef CONFIG_EFI_STUB +/* + * We don't need the return address, so set up the stack so efi_main() can find + * its arguments. + */ +ENTRY(efi_pe_entry) + add $0x4, %esp + + call 1f +1: popl %esi + subl $1b, %esi + + popl %ecx + movl %ecx, efi32_config(%esi) /* Handle */ + popl %ecx + movl %ecx, efi32_config+8(%esi) /* EFI System table pointer */ + + /* Relocate efi_config->call() */ + leal efi32_config(%esi), %eax + add %esi, 40(%eax) + pushl %eax + + call make_boot_params + cmpl $0, %eax + je fail + movl %esi, BP_code32_start(%eax) + popl %ecx + pushl %eax + pushl %ecx + jmp 2f /* Skip efi_config initialization */ +ENDPROC(efi_pe_entry) + +ENTRY(efi32_stub_entry) + add $0x4, %esp + popl %ecx + popl %edx + + call 1f +1: popl %esi + subl $1b, %esi + + movl %ecx, efi32_config(%esi) /* Handle */ + movl %edx, efi32_config+8(%esi) /* EFI System table pointer */ + + /* Relocate efi_config->call() */ + leal efi32_config(%esi), %eax + add %esi, 40(%eax) + pushl %eax +2: + call efi_main + cmpl $0, %eax + movl %eax, %esi + jne 2f +fail: + /* EFI init failed, so hang. */ + hlt + jmp fail +2: + movl BP_code32_start(%esi), %eax + leal startup_32(%eax), %eax + jmp *%eax +ENDPROC(efi32_stub_entry) +#endif + .text relocated: diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index fbf4c32d0b62..b4a5d284391c 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -243,65 +243,6 @@ ENTRY(startup_64) * that maps our entire kernel(text+data+bss+brk), zero page * and command line. */ -#ifdef CONFIG_EFI_STUB - /* - * The entry point for the PE/COFF executable is efi_pe_entry, so - * only legacy boot loaders will execute this jmp. - */ - jmp preferred_addr - -ENTRY(efi_pe_entry) - movq %rcx, efi64_config(%rip) /* Handle */ - movq %rdx, efi64_config+8(%rip) /* EFI System table pointer */ - - leaq efi64_config(%rip), %rax - movq %rax, efi_config(%rip) - - call 1f -1: popq %rbp - subq $1b, %rbp - - /* - * Relocate efi_config->call(). - */ - addq %rbp, efi64_config+40(%rip) - - movq %rax, %rdi - call make_boot_params - cmpq $0,%rax - je fail - mov %rax, %rsi - leaq startup_32(%rip), %rax - movl %eax, BP_code32_start(%rsi) - jmp 2f /* Skip the relocation */ - -handover_entry: - call 1f -1: popq %rbp - subq $1b, %rbp - - /* - * Relocate efi_config->call(). - */ - movq efi_config(%rip), %rax - addq %rbp, 40(%rax) -2: - movq efi_config(%rip), %rdi - call efi_main - movq %rax,%rsi - cmpq $0,%rax - jne 2f -fail: - /* EFI init failed, so hang. */ - hlt - jmp fail -2: - movl BP_code32_start(%esi), %eax - leaq preferred_addr(%rax), %rax - jmp *%rax - -preferred_addr: -#endif /* Setup data segments. */ xorl %eax, %eax @@ -413,6 +354,59 @@ lvl5: jmp *%rax #ifdef CONFIG_EFI_STUB + +/* The entry point for the PE/COFF executable is efi_pe_entry. */ +ENTRY(efi_pe_entry) + movq %rcx, efi64_config(%rip) /* Handle */ + movq %rdx, efi64_config+8(%rip) /* EFI System table pointer */ + + leaq efi64_config(%rip), %rax + movq %rax, efi_config(%rip) + + call 1f +1: popq %rbp + subq $1b, %rbp + + /* + * Relocate efi_config->call(). + */ + addq %rbp, efi64_config+40(%rip) + + movq %rax, %rdi + call make_boot_params + cmpq $0,%rax + je fail + mov %rax, %rsi + leaq startup_32(%rip), %rax + movl %eax, BP_code32_start(%rsi) + jmp 2f /* Skip the relocation */ + +handover_entry: + call 1f +1: popq %rbp + subq $1b, %rbp + + /* + * Relocate efi_config->call(). + */ + movq efi_config(%rip), %rax + addq %rbp, 40(%rax) +2: + movq efi_config(%rip), %rdi + call efi_main + movq %rax,%rsi + cmpq $0,%rax + jne 2f +fail: + /* EFI init failed, so hang. */ + hlt + jmp fail +2: + movl BP_code32_start(%esi), %eax + leaq startup_64(%rax), %rax + jmp *%rax +ENDPROC(efi_pe_entry) + .org 0x390 ENTRY(efi64_stub_entry) movq %rdi, efi64_config(%rip) /* Handle */ diff --git a/arch/x86/configs/tiny.config b/arch/x86/configs/tiny.config index 4b429df40d7a..550cd5012b73 100644 --- a/arch/x86/configs/tiny.config +++ b/arch/x86/configs/tiny.config @@ -1,3 +1,5 @@ CONFIG_NOHIGHMEM=y # CONFIG_HIGHMEM4G is not set # CONFIG_HIGHMEM64G is not set +CONFIG_GUESS_UNWINDER=y +# CONFIG_FRAME_POINTER_UNWINDER is not set diff --git a/arch/x86/entry/Makefile b/arch/x86/entry/Makefile index 9976fcecd17e..af28a8a24366 100644 --- a/arch/x86/entry/Makefile +++ b/arch/x86/entry/Makefile @@ -2,7 +2,6 @@ # Makefile for the x86 low level entry code # -OBJECT_FILES_NON_STANDARD_entry_$(BITS).o := y OBJECT_FILES_NON_STANDARD_entry_64_compat.o := y CFLAGS_syscall_64.o += $(call cc-option,-Wno-override-init,) diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h index 05ed3d393da7..640aafebdc00 100644 --- a/arch/x86/entry/calling.h +++ b/arch/x86/entry/calling.h @@ -1,4 +1,5 @@ #include <linux/jump_label.h> +#include <asm/unwind_hints.h> /* @@ -112,6 +113,7 @@ For 32-bit we have the following conventions - kernel is built with movq %rdx, 12*8+\offset(%rsp) movq %rsi, 13*8+\offset(%rsp) movq %rdi, 14*8+\offset(%rsp) + UNWIND_HINT_REGS offset=\offset extra=0 .endm .macro SAVE_C_REGS offset=0 SAVE_C_REGS_HELPER \offset, 1, 1, 1, 1 @@ -136,6 +138,7 @@ For 32-bit we have the following conventions - kernel is built with movq %r12, 3*8+\offset(%rsp) movq %rbp, 4*8+\offset(%rsp) movq %rbx, 5*8+\offset(%rsp) + UNWIND_HINT_REGS offset=\offset .endm .macro RESTORE_EXTRA_REGS offset=0 @@ -145,6 +148,7 @@ For 32-bit we have the following conventions - kernel is built with movq 3*8+\offset(%rsp), %r12 movq 4*8+\offset(%rsp), %rbp movq 5*8+\offset(%rsp), %rbx + UNWIND_HINT_REGS offset=\offset extra=0 .endm .macro RESTORE_C_REGS_HELPER rstor_rax=1, rstor_rcx=1, rstor_r11=1, rstor_r8910=1, rstor_rdx=1 @@ -167,6 +171,7 @@ For 32-bit we have the following conventions - kernel is built with .endif movq 13*8(%rsp), %rsi movq 14*8(%rsp), %rdi + UNWIND_HINT_IRET_REGS offset=16*8 .endm .macro RESTORE_C_REGS RESTORE_C_REGS_HELPER 1,1,1,1,1 diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index ce8dc33dd640..ca0b250eefc4 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -36,6 +36,7 @@ #include <asm/smap.h> #include <asm/pgtable_types.h> #include <asm/export.h> +#include <asm/frame.h> #include <linux/err.h> .code64 @@ -43,9 +44,10 @@ #ifdef CONFIG_PARAVIRT ENTRY(native_usergs_sysret64) + UNWIND_HINT_EMPTY swapgs sysretq -ENDPROC(native_usergs_sysret64) +END(native_usergs_sysret64) #endif /* CONFIG_PARAVIRT */ .macro TRACE_IRQS_IRETQ @@ -134,19 +136,14 @@ ENDPROC(native_usergs_sysret64) */ ENTRY(entry_SYSCALL_64) + UNWIND_HINT_EMPTY /* * Interrupts are off on entry. * We do not frame this tiny irq-off block with TRACE_IRQS_OFF/ON, * it is too small to ever cause noticeable irq latency. */ - SWAPGS_UNSAFE_STACK - /* - * A hypervisor implementation might want to use a label - * after the swapgs, so that it can do the swapgs - * for the guest and jump here on syscall. - */ -GLOBAL(entry_SYSCALL_64_after_swapgs) + swapgs movq %rsp, PER_CPU_VAR(rsp_scratch) movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp @@ -158,6 +155,7 @@ GLOBAL(entry_SYSCALL_64_after_swapgs) pushq %r11 /* pt_regs->flags */ pushq $__USER_CS /* pt_regs->cs */ pushq %rcx /* pt_regs->ip */ +GLOBAL(entry_SYSCALL_64_after_hwframe) pushq %rax /* pt_regs->orig_ax */ pushq %rdi /* pt_regs->di */ pushq %rsi /* pt_regs->si */ @@ -169,6 +167,7 @@ GLOBAL(entry_SYSCALL_64_after_swapgs) pushq %r10 /* pt_regs->r10 */ pushq %r11 /* pt_regs->r11 */ sub $(6*8), %rsp /* pt_regs->bp, bx, r12-15 not saved */ + UNWIND_HINT_REGS extra=0 /* * If we need to do entry work or if we guess we'll need to do @@ -223,6 +222,7 @@ entry_SYSCALL_64_fastpath: movq EFLAGS(%rsp), %r11 RESTORE_C_REGS_EXCEPT_RCX_R11 movq RSP(%rsp), %rsp + UNWIND_HINT_EMPTY USERGS_SYSRET64 1: @@ -316,6 +316,7 @@ syscall_return_via_sysret: /* rcx and r11 are already restored (see code above) */ RESTORE_C_REGS_EXCEPT_RCX_R11 movq RSP(%rsp), %rsp + UNWIND_HINT_EMPTY USERGS_SYSRET64 opportunistic_sysret_failed: @@ -343,6 +344,7 @@ ENTRY(stub_ptregs_64) DISABLE_INTERRUPTS(CLBR_ANY) TRACE_IRQS_OFF popq %rax + UNWIND_HINT_REGS extra=0 jmp entry_SYSCALL64_slow_path 1: @@ -351,6 +353,7 @@ END(stub_ptregs_64) .macro ptregs_stub func ENTRY(ptregs_\func) + UNWIND_HINT_FUNC leaq \func(%rip), %rax jmp stub_ptregs_64 END(ptregs_\func) @@ -367,6 +370,7 @@ END(ptregs_\func) * %rsi: next task */ ENTRY(__switch_to_asm) + UNWIND_HINT_FUNC /* * Save callee-saved registers * This must match the order in inactive_task_frame @@ -406,6 +410,7 @@ END(__switch_to_asm) * r12: kernel thread arg */ ENTRY(ret_from_fork) + UNWIND_HINT_EMPTY movq %rax, %rdi call schedule_tail /* rdi: 'prev' task parameter */ @@ -413,6 +418,7 @@ ENTRY(ret_from_fork) jnz 1f /* kernel threads are uncommon */ 2: + UNWIND_HINT_REGS movq %rsp, %rdi call syscall_return_slowpath /* returns with IRQs disabled */ TRACE_IRQS_ON /* user mode is traced as IRQS on */ @@ -440,13 +446,102 @@ END(ret_from_fork) ENTRY(irq_entries_start) vector=FIRST_EXTERNAL_VECTOR .rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR) + UNWIND_HINT_IRET_REGS pushq $(~vector+0x80) /* Note: always in signed byte range */ - vector=vector+1 jmp common_interrupt .align 8 + vector=vector+1 .endr END(irq_entries_start) +.macro DEBUG_ENTRY_ASSERT_IRQS_OFF +#ifdef CONFIG_DEBUG_ENTRY + pushfq + testl $X86_EFLAGS_IF, (%rsp) + jz .Lokay_\@ + ud2 +.Lokay_\@: + addq $8, %rsp +#endif +.endm + +/* + * Enters the IRQ stack if we're not already using it. NMI-safe. Clobbers + * flags and puts old RSP into old_rsp, and leaves all other GPRs alone. + * Requires kernel GSBASE. + * + * The invariant is that, if irq_count != -1, then the IRQ stack is in use. + */ +.macro ENTER_IRQ_STACK regs=1 old_rsp + DEBUG_ENTRY_ASSERT_IRQS_OFF + movq %rsp, \old_rsp + + .if \regs + UNWIND_HINT_REGS base=\old_rsp + .endif + + incl PER_CPU_VAR(irq_count) + jnz .Lirq_stack_push_old_rsp_\@ + + /* + * Right now, if we just incremented irq_count to zero, we've + * claimed the IRQ stack but we haven't switched to it yet. + * + * If anything is added that can interrupt us here without using IST, + * it must be *extremely* careful to limit its stack usage. This + * could include kprobes and a hypothetical future IST-less #DB + * handler. + * + * The OOPS unwinder relies on the word at the top of the IRQ + * stack linking back to the previous RSP for the entire time we're + * on the IRQ stack. For this to work reliably, we need to write + * it before we actually move ourselves to the IRQ stack. + */ + + movq \old_rsp, PER_CPU_VAR(irq_stack_union + IRQ_STACK_SIZE - 8) + movq PER_CPU_VAR(irq_stack_ptr), %rsp + +#ifdef CONFIG_DEBUG_ENTRY + /* + * If the first movq above becomes wrong due to IRQ stack layout + * changes, the only way we'll notice is if we try to unwind right + * here. Assert that we set up the stack right to catch this type + * of bug quickly. + */ + cmpq -8(%rsp), \old_rsp + je .Lirq_stack_okay\@ + ud2 + .Lirq_stack_okay\@: +#endif + +.Lirq_stack_push_old_rsp_\@: + pushq \old_rsp + + .if \regs + UNWIND_HINT_REGS indirect=1 + .endif +.endm + +/* + * Undoes ENTER_IRQ_STACK. + */ +.macro LEAVE_IRQ_STACK regs=1 + DEBUG_ENTRY_ASSERT_IRQS_OFF + /* We need to be off the IRQ stack before decrementing irq_count. */ + popq %rsp + + .if \regs + UNWIND_HINT_REGS + .endif + + /* + * As in ENTER_IRQ_STACK, irq_count == 0, we are still claiming + * the irq stack but we're not on it. + */ + + decl PER_CPU_VAR(irq_count) +.endm + /* * Interrupt entry/exit. * @@ -485,17 +580,7 @@ END(irq_entries_start) CALL_enter_from_user_mode 1: - /* - * Save previous stack pointer, optionally switch to interrupt stack. - * irq_count is used to check if a CPU is already on an interrupt stack - * or not. While this is essentially redundant with preempt_count it is - * a little cheaper to use a separate counter in the PDA (short of - * moving irq_enter into assembly, which would be too much work) - */ - movq %rsp, %rdi - incl PER_CPU_VAR(irq_count) - cmovzq PER_CPU_VAR(irq_stack_ptr), %rsp - pushq %rdi + ENTER_IRQ_STACK old_rsp=%rdi /* We entered an interrupt context - irqs are off: */ TRACE_IRQS_OFF @@ -515,10 +600,8 @@ common_interrupt: ret_from_intr: DISABLE_INTERRUPTS(CLBR_ANY) TRACE_IRQS_OFF - decl PER_CPU_VAR(irq_count) - /* Restore saved previous stack */ - popq %rsp + LEAVE_IRQ_STACK testb $3, CS(%rsp) jz retint_kernel @@ -561,6 +644,7 @@ restore_c_regs_and_iret: INTERRUPT_RETURN ENTRY(native_iret) + UNWIND_HINT_IRET_REGS /* * Are we returning to a stack segment from the LDT? Note: in * 64-bit mode SS:RSP on the exception stack is always valid. @@ -633,6 +717,7 @@ native_irq_return_ldt: orq PER_CPU_VAR(espfix_stack), %rax SWAPGS movq %rax, %rsp + UNWIND_HINT_IRET_REGS offset=8 /* * At this point, we cannot write to the stack any more, but we can @@ -654,6 +739,7 @@ END(common_interrupt) */ .macro apicinterrupt3 num sym do_sym ENTRY(\sym) + UNWIND_HINT_IRET_REGS ASM_CLAC pushq $~(\num) .Lcommon_\sym: @@ -735,6 +821,8 @@ apicinterrupt IRQ_WORK_VECTOR irq_work_interrupt smp_irq_work_interrupt .macro idtentry sym do_sym has_error_code:req paranoid=0 shift_ist=-1 ENTRY(\sym) + UNWIND_HINT_IRET_REGS offset=8 + /* Sanity check */ .if \shift_ist != -1 && \paranoid == 0 .error "using shift_ist requires paranoid=1" @@ -758,6 +846,7 @@ ENTRY(\sym) .else call error_entry .endif + UNWIND_HINT_REGS /* returned flag: ebx=0: need swapgs on exit, ebx=1: don't need it */ .if \paranoid @@ -855,6 +944,7 @@ idtentry simd_coprocessor_error do_simd_coprocessor_error has_error_code=0 * edi: new selector */ ENTRY(native_load_gs_index) + FRAME_BEGIN pushfq DISABLE_INTERRUPTS(CLBR_ANY & ~CLBR_RDI) SWAPGS @@ -863,8 +953,9 @@ ENTRY(native_load_gs_index) 2: ALTERNATIVE "", "mfence", X86_BUG_SWAPGS_FENCE SWAPGS popfq + FRAME_END ret -END(native_load_gs_index) +ENDPROC(native_load_gs_index) EXPORT_SYMBOL(native_load_gs_index) _ASM_EXTABLE(.Lgs_change, bad_gs) @@ -887,14 +978,12 @@ bad_gs: ENTRY(do_softirq_own_stack) pushq %rbp mov %rsp, %rbp - incl PER_CPU_VAR(irq_count) - cmove PER_CPU_VAR(irq_stack_ptr), %rsp - push %rbp /* frame pointer backlink */ + ENTER_IRQ_STACK regs=0 old_rsp=%r11 call __do_softirq + LEAVE_IRQ_STACK regs=0 leaveq - decl PER_CPU_VAR(irq_count) ret -END(do_softirq_own_stack) +ENDPROC(do_softirq_own_stack) #ifdef CONFIG_XEN idtentry xen_hypervisor_callback xen_do_hypervisor_callback has_error_code=0 @@ -918,14 +1007,14 @@ ENTRY(xen_do_hypervisor_callback) /* do_hypervisor_callback(struct *pt_regs) */ * Since we don't modify %rdi, evtchn_do_upall(struct *pt_regs) will * see the correct pointer to the pt_regs */ + UNWIND_HINT_FUNC movq %rdi, %rsp /* we don't return, adjust the stack frame */ -11: incl PER_CPU_VAR(irq_count) - movq %rsp, %rbp - cmovzq PER_CPU_VAR(irq_stack_ptr), %rsp - pushq %rbp /* frame pointer backlink */ + UNWIND_HINT_REGS + + ENTER_IRQ_STACK old_rsp=%r10 call xen_evtchn_do_upcall - popq %rsp - decl PER_CPU_VAR(irq_count) + LEAVE_IRQ_STACK + #ifndef CONFIG_PREEMPT call xen_maybe_preempt_hcall #endif @@ -946,6 +1035,7 @@ END(xen_do_hypervisor_callback) * with its current contents: any discrepancy means we in category 1. */ ENTRY(xen_failsafe_callback) + UNWIND_HINT_EMPTY movl %ds, %ecx cmpw %cx, 0x10(%rsp) jne 1f @@ -965,11 +1055,13 @@ ENTRY(xen_failsafe_callback) pushq $0 /* RIP */ pushq %r11 pushq %rcx + UNWIND_HINT_IRET_REGS offset=8 jmp general_protection 1: /* Segment mismatch => Category 1 (Bad segment). Retry the IRET. */ movq (%rsp), %rcx movq 8(%rsp), %r11 addq $0x30, %rsp + UNWIND_HINT_IRET_REGS pushq $-1 /* orig_ax = -1 => not a system call */ ALLOC_PT_GPREGS_ON_STACK SAVE_C_REGS @@ -1015,6 +1107,7 @@ idtentry machine_check has_error_code=0 paranoid=1 do_sym=*machine_check_vec * Return: ebx=0: need swapgs on exit, ebx=1: otherwise */ ENTRY(paranoid_entry) + UNWIND_HINT_FUNC cld SAVE_C_REGS 8 SAVE_EXTRA_REGS 8 @@ -1042,6 +1135,7 @@ END(paranoid_entry) * On entry, ebx is "no swapgs" flag (1: don't need swapgs, 0: need it) */ ENTRY(paranoid_exit) + UNWIND_HINT_REGS DISABLE_INTERRUPTS(CLBR_ANY) TRACE_IRQS_OFF_DEBUG testl %ebx, %ebx /* swapgs needed? */ @@ -1063,6 +1157,7 @@ END(paranoid_exit) * Return: EBX=0: came from user mode; EBX=1: otherwise */ ENTRY(error_entry) + UNWIND_HINT_FUNC cld SAVE_C_REGS 8 SAVE_EXTRA_REGS 8 @@ -1147,6 +1242,7 @@ END(error_entry) * 0: user gsbase is loaded, we need SWAPGS and standard preparation for return to usermode */ ENTRY(error_exit) + UNWIND_HINT_REGS DISABLE_INTERRUPTS(CLBR_ANY) TRACE_IRQS_OFF testl %ebx, %ebx @@ -1156,6 +1252,7 @@ END(error_exit) /* Runs on exception stack */ ENTRY(nmi) + UNWIND_HINT_IRET_REGS /* * Fix up the exception frame if we're on Xen. * PARAVIRT_ADJUST_EXCEPTION_FRAME is guaranteed to push at most @@ -1229,11 +1326,13 @@ ENTRY(nmi) cld movq %rsp, %rdx movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp + UNWIND_HINT_IRET_REGS base=%rdx offset=8 pushq 5*8(%rdx) /* pt_regs->ss */ pushq 4*8(%rdx) /* pt_regs->rsp */ pushq 3*8(%rdx) /* pt_regs->flags */ pushq 2*8(%rdx) /* pt_regs->cs */ pushq 1*8(%rdx) /* pt_regs->rip */ + UNWIND_HINT_IRET_REGS pushq $-1 /* pt_regs->orig_ax */ pushq %rdi /* pt_regs->di */ pushq %rsi /* pt_regs->si */ @@ -1250,6 +1349,7 @@ ENTRY(nmi) pushq %r13 /* pt_regs->r13 */ pushq %r14 /* pt_regs->r14 */ pushq %r15 /* pt_regs->r15 */ + UNWIND_HINT_REGS ENCODE_FRAME_POINTER /* @@ -1404,6 +1504,7 @@ first_nmi: .rept 5 pushq 11*8(%rsp) .endr + UNWIND_HINT_IRET_REGS /* Everything up to here is safe from nested NMIs */ @@ -1419,6 +1520,7 @@ first_nmi: pushq $__KERNEL_CS /* CS */ pushq $1f /* RIP */ INTERRUPT_RETURN /* continues at repeat_nmi below */ + UNWIND_HINT_IRET_REGS 1: #endif @@ -1468,6 +1570,7 @@ end_repeat_nmi: * exceptions might do. */ call paranoid_entry + UNWIND_HINT_REGS /* paranoidentry do_nmi, 0; without TRACE_IRQS_OFF */ movq %rsp, %rdi @@ -1505,17 +1608,19 @@ nmi_restore: END(nmi) ENTRY(ignore_sysret) + UNWIND_HINT_EMPTY mov $-ENOSYS, %eax sysret END(ignore_sysret) ENTRY(rewind_stack_do_exit) + UNWIND_HINT_FUNC /* Prevent any naive code from trying to unwind to our caller. */ xorl %ebp, %ebp movq PER_CPU_VAR(cpu_current_top_of_stack), %rax - leaq -TOP_OF_KERNEL_STACK_PADDING-PTREGS_SIZE(%rax), %rsp + leaq -PTREGS_SIZE(%rax), %rsp + UNWIND_HINT_FUNC sp_offset=PTREGS_SIZE call do_exit -1: jmp 1b END(rewind_stack_do_exit) diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S index e1721dafbcb1..4b86d8da3ea3 100644 --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -183,21 +183,20 @@ ENDPROC(entry_SYSENTER_compat) */ ENTRY(entry_SYSCALL_compat) /* Interrupts are off on entry. */ - SWAPGS_UNSAFE_STACK + swapgs /* Stash user ESP and switch to the kernel stack. */ movl %esp, %r8d movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp - /* Zero-extending 32-bit regs, do not remove */ - movl %eax, %eax - /* Construct struct pt_regs on stack */ pushq $__USER32_DS /* pt_regs->ss */ pushq %r8 /* pt_regs->sp */ pushq %r11 /* pt_regs->flags */ pushq $__USER32_CS /* pt_regs->cs */ pushq %rcx /* pt_regs->ip */ +GLOBAL(entry_SYSCALL_compat_after_hwframe) + movl %eax, %eax /* discard orig_ax high bits */ pushq %rax /* pt_regs->orig_ax */ pushq %rdi /* pt_regs->di */ pushq %rsi /* pt_regs->si */ @@ -342,8 +341,7 @@ ENTRY(entry_INT80_compat) jmp restore_regs_and_iret END(entry_INT80_compat) - ALIGN -GLOBAL(stub32_clone) +ENTRY(stub32_clone) /* * The 32-bit clone ABI is: clone(..., int tls_val, int *child_tidptr). * The 64-bit clone ABI is: clone(..., int *child_tidptr, int tls_val). @@ -353,3 +351,4 @@ GLOBAL(stub32_clone) */ xchg %r8, %rcx jmp sys_clone +ENDPROC(stub32_clone) diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c index 724153797209..e0bb46c02857 100644 --- a/arch/x86/ia32/ia32_signal.c +++ b/arch/x86/ia32/ia32_signal.c @@ -226,7 +226,7 @@ static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, if (ksig->ka.sa.sa_flags & SA_ONSTACK) sp = sigsp(sp, ksig); /* This is the legacy signal stack switching. */ - else if ((regs->ss & 0xffff) != __USER32_DS && + else if (regs->ss != __USER32_DS && !(ksig->ka.sa.sa_flags & SA_RESTORER) && ksig->ka.sa.sa_restorer) sp = (unsigned long) ksig->ka.sa.sa_restorer; diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h index 9aeb91935ce0..bda9f94bcb10 100644 --- a/arch/x86/include/asm/elf.h +++ b/arch/x86/include/asm/elf.h @@ -126,15 +126,15 @@ do { \ pr_reg[4] = regs->di; \ pr_reg[5] = regs->bp; \ pr_reg[6] = regs->ax; \ - pr_reg[7] = regs->ds & 0xffff; \ - pr_reg[8] = regs->es & 0xffff; \ - pr_reg[9] = regs->fs & 0xffff; \ + pr_reg[7] = regs->ds; \ + pr_reg[8] = regs->es; \ + pr_reg[9] = regs->fs; \ pr_reg[11] = regs->orig_ax; \ pr_reg[12] = regs->ip; \ - pr_reg[13] = regs->cs & 0xffff; \ + pr_reg[13] = regs->cs; \ pr_reg[14] = regs->flags; \ pr_reg[15] = regs->sp; \ - pr_reg[16] = regs->ss & 0xffff; \ + pr_reg[16] = regs->ss; \ } while (0); #define ELF_CORE_COPY_REGS(pr_reg, regs) \ @@ -204,6 +204,7 @@ void set_personality_ia32(bool); #define ELF_CORE_COPY_REGS(pr_reg, regs) \ do { \ + unsigned long base; \ unsigned v; \ (pr_reg)[0] = (regs)->r15; \ (pr_reg)[1] = (regs)->r14; \ @@ -226,8 +227,8 @@ do { \ (pr_reg)[18] = (regs)->flags; \ (pr_reg)[19] = (regs)->sp; \ (pr_reg)[20] = (regs)->ss; \ - (pr_reg)[21] = current->thread.fsbase; \ - (pr_reg)[22] = current->thread.gsbase; \ + rdmsrl(MSR_FS_BASE, base); (pr_reg)[21] = base; \ + rdmsrl(MSR_KERNEL_GS_BASE, base); (pr_reg)[22] = base; \ asm("movl %%ds,%0" : "=r" (v)); (pr_reg)[23] = v; \ asm("movl %%es,%0" : "=r" (v)); (pr_reg)[24] = v; \ asm("movl %%fs,%0" : "=r" (v)); (pr_reg)[25] = v; \ diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h index 48febf07e828..1310e1f1cd65 100644 --- a/arch/x86/include/asm/io.h +++ b/arch/x86/include/asm/io.h @@ -69,6 +69,9 @@ build_mmio_write(__writeb, "b", unsigned char, "q", ) build_mmio_write(__writew, "w", unsigned short, "r", ) build_mmio_write(__writel, "l", unsigned int, "r", ) +#define readb readb +#define readw readw +#define readl readl #define readb_relaxed(a) __readb(a) #define readw_relaxed(a) __readw(a) #define readl_relaxed(a) __readl(a) @@ -76,6 +79,9 @@ build_mmio_write(__writel, "l", unsigned int, "r", ) #define __raw_readw __readw #define __raw_readl __readl +#define writeb writeb +#define writew writew +#define writel writel #define writeb_relaxed(v, a) __writeb(v, a) #define writew_relaxed(v, a) __writew(v, a) #define writel_relaxed(v, a) __writel(v, a) @@ -88,13 +94,15 @@ build_mmio_write(__writel, "l", unsigned int, "r", ) #ifdef CONFIG_X86_64 build_mmio_read(readq, "q", unsigned long, "=r", :"memory") +build_mmio_read(__readq, "q", unsigned long, "=r", ) build_mmio_write(writeq, "q", unsigned long, "r", :"memory") +build_mmio_write(__writeq, "q", unsigned long, "r", ) -#define readq_relaxed(a) readq(a) -#define writeq_relaxed(v, a) writeq(v, a) +#define readq_relaxed(a) __readq(a) +#define writeq_relaxed(v, a) __writeq(v, a) -#define __raw_readq(a) readq(a) -#define __raw_writeq(val, addr) writeq(val, addr) +#define __raw_readq __readq +#define __raw_writeq __writeq /* Let people know that we have them */ #define readq readq @@ -119,6 +127,7 @@ static inline phys_addr_t virt_to_phys(volatile void *address) { return __pa(address); } +#define virt_to_phys virt_to_phys /** * phys_to_virt - map physical address to virtual @@ -137,6 +146,7 @@ static inline void *phys_to_virt(phys_addr_t address) { return __va(address); } +#define phys_to_virt phys_to_virt /* * Change "struct page" to physical address. @@ -169,11 +179,14 @@ static inline unsigned int isa_virt_to_bus(volatile void *address) * else, you probably want one of the following. */ extern void __iomem *ioremap_nocache(resource_size_t offset, unsigned long size); +#define ioremap_nocache ioremap_nocache extern void __iomem *ioremap_uc(resource_size_t offset, unsigned long size); #define ioremap_uc ioremap_uc extern void __iomem *ioremap_cache(resource_size_t offset, unsigned long size); +#define ioremap_cache ioremap_cache extern void __iomem *ioremap_prot(resource_size_t offset, unsigned long size, unsigned long prot_val); +#define ioremap_prot ioremap_prot /** * ioremap - map bus memory into CPU space @@ -193,8 +206,10 @@ static inline void __iomem *ioremap(resource_size_t offset, unsigned long size) { return ioremap_nocache(offset, size); } +#define ioremap ioremap extern void iounmap(volatile void __iomem *addr); +#define iounmap iounmap extern void set_iounmap_nonlazy(void); @@ -203,53 +218,6 @@ extern void set_iounmap_nonlazy(void); #include <asm-generic/iomap.h> /* - * Convert a virtual cached pointer to an uncached pointer - */ -#define xlate_dev_kmem_ptr(p) p - -/** - * memset_io Set a range of I/O memory to a constant value - * @addr: The beginning of the I/O-memory range to set - * @val: The value to set the memory to - * @count: The number of bytes to set - * - * Set a range of I/O memory to a given value. - */ -static inline void -memset_io(volatile void __iomem *addr, unsigned char val, size_t count) -{ - memset((void __force *)addr, val, count); -} - -/** - * memcpy_fromio Copy a block of data from I/O memory - * @dst: The (RAM) destination for the copy - * @src: The (I/O memory) source for the data - * @count: The number of bytes to copy - * - * Copy a block of data from I/O memory. - */ -static inline void -memcpy_fromio(void *dst, const volatile void __iomem *src, size_t count) -{ - memcpy(dst, (const void __force *)src, count); -} - -/** - * memcpy_toio Copy a block of data into I/O memory - * @dst: The (I/O memory) destination for the copy - * @src: The (RAM) source for the data - * @count: The number of bytes to copy - * - * Copy a block of data to I/O memory. - */ -static inline void -memcpy_toio(volatile void __iomem *dst, const void *src, size_t count) -{ - memcpy((void __force *)dst, src, count); -} - -/* * ISA space is 'always mapped' on a typical x86 system, no need to * explicitly ioremap() it. The fact that the ISA IO space is mapped * to PAGE_OFFSET is pure coincidence - it does not mean ISA values @@ -341,13 +309,38 @@ BUILDIO(b, b, char) BUILDIO(w, w, short) BUILDIO(l, , int) +#define inb inb +#define inw inw +#define inl inl +#define inb_p inb_p +#define inw_p inw_p +#define inl_p inl_p +#define insb insb +#define insw insw +#define insl insl + +#define outb outb +#define outw outw +#define outl outl +#define outb_p outb_p +#define outw_p outw_p +#define outl_p outl_p +#define outsb outsb +#define outsw outsw +#define outsl outsl + extern void *xlate_dev_mem_ptr(phys_addr_t phys); extern void unxlate_dev_mem_ptr(phys_addr_t phys, void *addr); +#define xlate_dev_mem_ptr xlate_dev_mem_ptr +#define unxlate_dev_mem_ptr unxlate_dev_mem_ptr + extern int ioremap_change_attr(unsigned long vaddr, unsigned long size, enum page_cache_mode pcm); extern void __iomem *ioremap_wc(resource_size_t offset, unsigned long size); +#define ioremap_wc ioremap_wc extern void __iomem *ioremap_wt(resource_size_t offset, unsigned long size); +#define ioremap_wt ioremap_wt extern bool is_early_ioremap_ptep(pte_t *ptep); @@ -365,6 +358,9 @@ extern bool xen_biovec_phys_mergeable(const struct bio_vec *vec1, #define IO_SPACE_LIMIT 0xffff +#include <asm-generic/io.h> +#undef PCI_IOBASE + #ifdef CONFIG_MTRR extern int __must_check arch_phys_wc_index(int handle); #define arch_phys_wc_index arch_phys_wc_index diff --git a/arch/x86/include/asm/lguest.h b/arch/x86/include/asm/lguest.h deleted file mode 100644 index 73d0c9b92087..000000000000 --- a/arch/x86/include/asm/lguest.h +++ /dev/null @@ -1,91 +0,0 @@ -#ifndef _ASM_X86_LGUEST_H -#define _ASM_X86_LGUEST_H - -#define GDT_ENTRY_LGUEST_CS 10 -#define GDT_ENTRY_LGUEST_DS 11 -#define LGUEST_CS (GDT_ENTRY_LGUEST_CS * 8) -#define LGUEST_DS (GDT_ENTRY_LGUEST_DS * 8) - -#ifndef __ASSEMBLY__ -#include <asm/desc.h> - -#define GUEST_PL 1 - -/* Page for Switcher text itself, then two pages per cpu */ -#define SWITCHER_TEXT_PAGES (1) -#define SWITCHER_STACK_PAGES (2 * nr_cpu_ids) -#define TOTAL_SWITCHER_PAGES (SWITCHER_TEXT_PAGES + SWITCHER_STACK_PAGES) - -/* Where we map the Switcher, in both Host and Guest. */ -extern unsigned long switcher_addr; - -/* Found in switcher.S */ -extern unsigned long default_idt_entries[]; - -/* Declarations for definitions in arch/x86/lguest/head_32.S */ -extern char lguest_noirq_iret[]; -extern const char lgstart_cli[], lgend_cli[]; -extern const char lgstart_pushf[], lgend_pushf[]; - -extern void lguest_iret(void); -extern void lguest_init(void); - -struct lguest_regs { - /* Manually saved part. */ - unsigned long eax, ebx, ecx, edx; - unsigned long esi, edi, ebp; - unsigned long gs; - unsigned long fs, ds, es; - unsigned long trapnum, errcode; - /* Trap pushed part */ - unsigned long eip; - unsigned long cs; - unsigned long eflags; - unsigned long esp; - unsigned long ss; -}; - -/* This is a guest-specific page (mapped ro) into the guest. */ -struct lguest_ro_state { - /* Host information we need to restore when we switch back. */ - u32 host_cr3; - struct desc_ptr host_idt_desc; - struct desc_ptr host_gdt_desc; - u32 host_sp; - - /* Fields which are used when guest is running. */ - struct desc_ptr guest_idt_desc; - struct desc_ptr guest_gdt_desc; - struct x86_hw_tss guest_tss; - struct desc_struct guest_idt[IDT_ENTRIES]; - struct desc_struct guest_gdt[GDT_ENTRIES]; -}; - -struct lg_cpu_arch { - /* The GDT entries copied into lguest_ro_state when running. */ - struct desc_struct gdt[GDT_ENTRIES]; - - /* The IDT entries: some copied into lguest_ro_state when running. */ - struct desc_struct idt[IDT_ENTRIES]; - - /* The address of the last guest-visible pagefault (ie. cr2). */ - unsigned long last_pagefault; -}; - -static inline void lguest_set_ts(void) -{ - u32 cr0; - - cr0 = read_cr0(); - if (!(cr0 & 8)) - write_cr0(cr0 | 8); -} - -/* Full 4G segment descriptors, suitable for CS and DS. */ -#define FULL_EXEC_SEGMENT \ - ((struct desc_struct)GDT_ENTRY_INIT(0xc09b, 0, 0xfffff)) -#define FULL_SEGMENT ((struct desc_struct)GDT_ENTRY_INIT(0xc093, 0, 0xfffff)) - -#endif /* __ASSEMBLY__ */ - -#endif /* _ASM_X86_LGUEST_H */ diff --git a/arch/x86/include/asm/lguest_hcall.h b/arch/x86/include/asm/lguest_hcall.h deleted file mode 100644 index 6c119cfae218..000000000000 --- a/arch/x86/include/asm/lguest_hcall.h +++ /dev/null @@ -1,74 +0,0 @@ -/* Architecture specific portion of the lguest hypercalls */ -#ifndef _ASM_X86_LGUEST_HCALL_H -#define _ASM_X86_LGUEST_HCALL_H - -#define LHCALL_FLUSH_ASYNC 0 -#define LHCALL_LGUEST_INIT 1 -#define LHCALL_SHUTDOWN 2 -#define LHCALL_NEW_PGTABLE 4 -#define LHCALL_FLUSH_TLB 5 -#define LHCALL_LOAD_IDT_ENTRY 6 -#define LHCALL_SET_STACK 7 -#define LHCALL_SET_CLOCKEVENT 9 -#define LHCALL_HALT 10 -#define LHCALL_SET_PMD 13 -#define LHCALL_SET_PTE 14 -#define LHCALL_SET_PGD 15 -#define LHCALL_LOAD_TLS 16 -#define LHCALL_LOAD_GDT_ENTRY 18 -#define LHCALL_SEND_INTERRUPTS 19 - -#define LGUEST_TRAP_ENTRY 0x1F - -/* Argument number 3 to LHCALL_LGUEST_SHUTDOWN */ -#define LGUEST_SHUTDOWN_POWEROFF 1 -#define LGUEST_SHUTDOWN_RESTART 2 - -#ifndef __ASSEMBLY__ -#include <asm/hw_irq.h> - -/*G:030 - * But first, how does our Guest contact the Host to ask for privileged - * operations? There are two ways: the direct way is to make a "hypercall", - * to make requests of the Host Itself. - * - * Our hypercall mechanism uses the highest unused trap code (traps 32 and - * above are used by real hardware interrupts). Seventeen hypercalls are - * available: the hypercall number is put in the %eax register, and the - * arguments (when required) are placed in %ebx, %ecx, %edx and %esi. - * If a return value makes sense, it's returned in %eax. - * - * Grossly invalid calls result in Sudden Death at the hands of the vengeful - * Host, rather than returning failure. This reflects Winston Churchill's - * definition of a gentleman: "someone who is only rude intentionally". - */ -static inline unsigned long -hcall(unsigned long call, - unsigned long arg1, unsigned long arg2, unsigned long arg3, - unsigned long arg4) -{ - /* "int" is the Intel instruction to trigger a trap. */ - asm volatile("int $" __stringify(LGUEST_TRAP_ENTRY) - /* The call in %eax (aka "a") might be overwritten */ - : "=a"(call) - /* The arguments are in %eax, %ebx, %ecx, %edx & %esi */ - : "a"(call), "b"(arg1), "c"(arg2), "d"(arg3), "S"(arg4) - /* "memory" means this might write somewhere in memory. - * This isn't true for all calls, but it's safe to tell - * gcc that it might happen so it doesn't get clever. */ - : "memory"); - return call; -} -/*:*/ - -/* Can't use our min() macro here: needs to be a constant */ -#define LGUEST_IRQS (NR_IRQS < 32 ? NR_IRQS: 32) - -#define LHCALL_RING_SIZE 64 -struct hcall_args { - /* These map directly onto eax/ebx/ecx/edx/esi in struct lguest_regs */ - unsigned long arg0, arg1, arg2, arg3, arg4; -}; - -#endif /* !__ASSEMBLY__ */ -#endif /* _ASM_X86_LGUEST_HCALL_H */ diff --git a/arch/x86/include/asm/module.h b/arch/x86/include/asm/module.h index e3b7819caeef..9eb7c718aaf8 100644 --- a/arch/x86/include/asm/module.h +++ b/arch/x86/include/asm/module.h @@ -2,6 +2,15 @@ #define _ASM_X86_MODULE_H #include <asm-generic/module.h> +#include <asm/orc_types.h> + +struct mod_arch_specific { +#ifdef CONFIG_ORC_UNWINDER + unsigned int num_orcs; + int *orc_unwind_ip; + struct orc_entry *orc_unwind; +#endif +}; #ifdef CONFIG_X86_64 /* X86_64 does not define MODULE_PROC_FAMILY */ diff --git a/arch/x86/include/asm/orc_lookup.h b/arch/x86/include/asm/orc_lookup.h new file mode 100644 index 000000000000..91c8d868424d --- /dev/null +++ b/arch/x86/include/asm/orc_lookup.h @@ -0,0 +1,46 @@ +/* + * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <http://www.gnu.org/licenses/>. + */ +#ifndef _ORC_LOOKUP_H +#define _ORC_LOOKUP_H + +/* + * This is a lookup table for speeding up access to the .orc_unwind table. + * Given an input address offset, the corresponding lookup table entry + * specifies a subset of the .orc_unwind table to search. + * + * Each block represents the end of the previous range and the start of the + * next range. An extra block is added to give the last range an end. + * + * The block size should be a power of 2 to avoid a costly 'div' instruction. + * + * A block size of 256 was chosen because it roughly doubles unwinder + * performance while only adding ~5% to the ORC data footprint. + */ +#define LOOKUP_BLOCK_ORDER 8 +#define LOOKUP_BLOCK_SIZE (1 << LOOKUP_BLOCK_ORDER) + +#ifndef LINKER_SCRIPT + +extern unsigned int orc_lookup[]; +extern unsigned int orc_lookup_end[]; + +#define LOOKUP_START_IP (unsigned long)_stext +#define LOOKUP_STOP_IP (unsigned long)_etext + +#endif /* LINKER_SCRIPT */ + +#endif /* _ORC_LOOKUP_H */ diff --git a/arch/x86/include/asm/orc_types.h b/arch/x86/include/asm/orc_types.h new file mode 100644 index 000000000000..9c9dc579bd7d --- /dev/null +++ b/arch/x86/include/asm/orc_types.h @@ -0,0 +1,107 @@ +/* + * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <http://www.gnu.org/licenses/>. + */ + +#ifndef _ORC_TYPES_H +#define _ORC_TYPES_H + +#include <linux/types.h> +#include <linux/compiler.h> + +/* + * The ORC_REG_* registers are base registers which are used to find other + * registers on the stack. + * + * ORC_REG_PREV_SP, also known as DWARF Call Frame Address (CFA), is the + * address of the previous frame: the caller's SP before it called the current + * function. + * + * ORC_REG_UNDEFINED means the corresponding register's value didn't change in + * the current frame. + * + * The most commonly used base registers are SP and BP -- which the previous SP + * is usually based on -- and PREV_SP and UNDEFINED -- which the previous BP is + * usually based on. + * + * The rest of the base registers are needed for special cases like entry code + * and GCC realigned stacks. + */ +#define ORC_REG_UNDEFINED 0 +#define ORC_REG_PREV_SP 1 +#define ORC_REG_DX 2 +#define ORC_REG_DI 3 +#define ORC_REG_BP 4 +#define ORC_REG_SP 5 +#define ORC_REG_R10 6 +#define ORC_REG_R13 7 +#define ORC_REG_BP_INDIRECT 8 +#define ORC_REG_SP_INDIRECT 9 +#define ORC_REG_MAX 15 + +/* + * ORC_TYPE_CALL: Indicates that sp_reg+sp_offset resolves to PREV_SP (the + * caller's SP right before it made the call). Used for all callable + * functions, i.e. all C code and all callable asm functions. + * + * ORC_TYPE_REGS: Used in entry code to indicate that sp_reg+sp_offset points + * to a fully populated pt_regs from a syscall, interrupt, or exception. + * + * ORC_TYPE_REGS_IRET: Used in entry code to indicate that sp_reg+sp_offset + * points to the iret return frame. + * + * The UNWIND_HINT macros are used only for the unwind_hint struct. They + * aren't used in struct orc_entry due to size and complexity constraints. + * Objtool converts them to real types when it converts the hints to orc + * entries. + */ +#define ORC_TYPE_CALL 0 +#define ORC_TYPE_REGS 1 +#define ORC_TYPE_REGS_IRET 2 +#define UNWIND_HINT_TYPE_SAVE 3 +#define UNWIND_HINT_TYPE_RESTORE 4 + +#ifndef __ASSEMBLY__ +/* + * This struct is more or less a vastly simplified version of the DWARF Call + * Frame Information standard. It contains only the necessary parts of DWARF + * CFI, simplified for ease of access by the in-kernel unwinder. It tells the + * unwinder how to find the previous SP and BP (and sometimes entry regs) on + * the stack for a given code address. Each instance of the struct corresponds + * to one or more code locations. + */ +struct orc_entry { + s16 sp_offset; + s16 bp_offset; + unsigned sp_reg:4; + unsigned bp_reg:4; + unsigned type:2; +} __packed; + +/* + * This struct is used by asm and inline asm code to manually annotate the + * location of registers on the stack for the ORC unwinder. + * + * Type can be either ORC_TYPE_* or UNWIND_HINT_TYPE_*. + */ +struct unwind_hint { + u32 ip; + s16 sp_offset; + u8 sp_reg; + u8 type; +}; +#endif /* __ASSEMBLY__ */ + +#endif /* _ORC_TYPES_H */ diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 028245e1c42b..abc99b9c7ffd 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -22,6 +22,7 @@ struct vm86; #include <asm/nops.h> #include <asm/special_insns.h> #include <asm/fpu/types.h> +#include <asm/unwind_hints.h> #include <linux/personality.h> #include <linux/cache.h> @@ -661,7 +662,7 @@ static inline void sync_core(void) * In case NMI unmasking or performance ever becomes a problem, * the next best option appears to be MOV-to-CR2 and an * unconditional jump. That sequence also works on all CPUs, - * but it will fault at CPL3 (i.e. Xen PV and lguest). + * but it will fault at CPL3 (i.e. Xen PV). * * CPUID is the conventional way, but it's nasty: it doesn't * exist on some 486-like CPUs, and it usually exits to a @@ -684,6 +685,7 @@ static inline void sync_core(void) unsigned int tmp; asm volatile ( + UNWIND_HINT_SAVE "mov %%ss, %0\n\t" "pushq %q0\n\t" "pushq %%rsp\n\t" @@ -693,6 +695,7 @@ static inline void sync_core(void) "pushq %q0\n\t" "pushq $1f\n\t" "iretq\n\t" + UNWIND_HINT_RESTORE "1:" : "=&r" (tmp), "+r" (__sp) : : "cc", "memory"); #endif diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h index 2b5d686ea9f3..91c04c8e67fa 100644 --- a/arch/x86/include/asm/ptrace.h +++ b/arch/x86/include/asm/ptrace.h @@ -9,6 +9,20 @@ #ifdef __i386__ struct pt_regs { + /* + * NB: 32-bit x86 CPUs are inconsistent as what happens in the + * following cases (where %seg represents a segment register): + * + * - pushl %seg: some do a 16-bit write and leave the high + * bits alone + * - movl %seg, [mem]: some do a 16-bit write despite the movl + * - IDT entry: some (e.g. 486) will leave the high bits of CS + * and (if applicable) SS undefined. + * + * Fortunately, x86-32 doesn't read the high bits on POP or IRET, + * so we can just treat all of the segment registers as 16-bit + * values. + */ unsigned long bx; unsigned long cx; unsigned long dx; @@ -16,16 +30,22 @@ struct pt_regs { unsigned long di; unsigned long bp; unsigned long ax; - unsigned long ds; - unsigned long es; - unsigned long fs; - unsigned long gs; + unsigned short ds; + unsigned short __dsh; + unsigned short es; + unsigned short __esh; + unsigned short fs; + unsigned short __fsh; + unsigned short gs; + unsigned short __gsh; unsigned long orig_ax; unsigned long ip; - unsigned long cs; + unsigned short cs; + unsigned short __csh; unsigned long flags; unsigned long sp; - unsigned long ss; + unsigned short ss; + unsigned short __ssh; }; #else /* __i386__ */ @@ -176,6 +196,17 @@ static inline unsigned long regs_get_register(struct pt_regs *regs, if (offset == offsetof(struct pt_regs, sp) && regs->cs == __KERNEL_CS) return kernel_stack_pointer(regs); + + /* The selector fields are 16-bit. */ + if (offset == offsetof(struct pt_regs, cs) || + offset == offsetof(struct pt_regs, ss) || + offset == offsetof(struct pt_regs, ds) || + offset == offsetof(struct pt_regs, es) || + offset == offsetof(struct pt_regs, fs) || + offset == offsetof(struct pt_regs, gs)) { + return *(u16 *)((unsigned long)regs + offset); + + } #endif return *(unsigned long *)((unsigned long)regs + offset); } diff --git a/arch/x86/include/asm/rmwcc.h b/arch/x86/include/asm/rmwcc.h index 661dd305694a..045f99211a99 100644 --- a/arch/x86/include/asm/rmwcc.h +++ b/arch/x86/include/asm/rmwcc.h @@ -1,45 +1,56 @@ #ifndef _ASM_X86_RMWcc #define _ASM_X86_RMWcc +#define __CLOBBERS_MEM "memory" +#define __CLOBBERS_MEM_CC_CX "memory", "cc", "cx" + #if !defined(__GCC_ASM_FLAG_OUTPUTS__) && defined(CC_HAVE_ASM_GOTO) /* Use asm goto */ -#define __GEN_RMWcc(fullop, var, cc, ...) \ +#define __GEN_RMWcc(fullop, var, cc, clobbers, ...) \ do { \ asm_volatile_goto (fullop "; j" #cc " %l[cc_label]" \ - : : "m" (var), ## __VA_ARGS__ \ - : "memory" : cc_label); \ + : : [counter] "m" (var), ## __VA_ARGS__ \ + : clobbers : cc_label); \ return 0; \ cc_label: \ return 1; \ } while (0) -#define GEN_UNARY_RMWcc(op, var, arg0, cc) \ - __GEN_RMWcc(op " " arg0, var, cc) +#define __BINARY_RMWcc_ARG " %1, " -#define GEN_BINARY_RMWcc(op, var, vcon, val, arg0, cc) \ - __GEN_RMWcc(op " %1, " arg0, var, cc, vcon (val)) #else /* defined(__GCC_ASM_FLAG_OUTPUTS__) || !defined(CC_HAVE_ASM_GOTO) */ /* Use flags output or a set instruction */ -#define __GEN_RMWcc(fullop, var, cc, ...) \ +#define __GEN_RMWcc(fullop, var, cc, clobbers, ...) \ do { \ bool c; \ asm volatile (fullop ";" CC_SET(cc) \ - : "+m" (var), CC_OUT(cc) (c) \ - : __VA_ARGS__ : "memory"); \ + : [counter] "+m" (var), CC_OUT(cc) (c) \ + : __VA_ARGS__ : clobbers); \ return c; \ } while (0) +#define __BINARY_RMWcc_ARG " %2, " + +#endif /* defined(__GCC_ASM_FLAG_OUTPUTS__) || !defined(CC_HAVE_ASM_GOTO) */ + #define GEN_UNARY_RMWcc(op, var, arg0, cc) \ - __GEN_RMWcc(op " " arg0, var, cc) + __GEN_RMWcc(op " " arg0, var, cc, __CLOBBERS_MEM) + +#define GEN_UNARY_SUFFIXED_RMWcc(op, suffix, var, arg0, cc) \ + __GEN_RMWcc(op " " arg0 "\n\t" suffix, var, cc, \ + __CLOBBERS_MEM_CC_CX) #define GEN_BINARY_RMWcc(op, var, vcon, val, arg0, cc) \ - __GEN_RMWcc(op " %2, " arg0, var, cc, vcon (val)) + __GEN_RMWcc(op __BINARY_RMWcc_ARG arg0, var, cc, \ + __CLOBBERS_MEM, vcon (val)) -#endif /* defined(__GCC_ASM_FLAG_OUTPUTS__) || !defined(CC_HAVE_ASM_GOTO) */ +#define GEN_BINARY_SUFFIXED_RMWcc(op, suffix, var, vcon, val, arg0, cc) \ + __GEN_RMWcc(op __BINARY_RMWcc_ARG arg0 "\n\t" suffix, var, cc, \ + __CLOBBERS_MEM_CC_CX, vcon (val)) #endif /* _ASM_X86_RMWcc */ diff --git a/arch/x86/include/asm/unwind.h b/arch/x86/include/asm/unwind.h index e6676495b125..e9f793e2df7a 100644 --- a/arch/x86/include/asm/unwind.h +++ b/arch/x86/include/asm/unwind.h @@ -12,11 +12,14 @@ struct unwind_state { struct task_struct *task; int graph_idx; bool error; -#ifdef CONFIG_FRAME_POINTER +#if defined(CONFIG_ORC_UNWINDER) + bool signal, full_regs; + unsigned long sp, bp, ip; + struct pt_regs *regs; +#elif defined(CONFIG_FRAME_POINTER_UNWINDER) bool got_irq; - unsigned long *bp, *orig_sp; + unsigned long *bp, *orig_sp, ip; struct pt_regs *regs; - unsigned long ip; #else unsigned long *sp; #endif @@ -24,41 +27,30 @@ struct unwind_state { void __unwind_start(struct unwind_state *state, struct task_struct *task, struct pt_regs *regs, unsigned long *first_frame); - bool unwind_next_frame(struct unwind_state *state); - unsigned long unwind_get_return_address(struct unwind_state *state); +unsigned long *unwind_get_return_address_ptr(struct unwind_state *state); static inline bool unwind_done(struct unwind_state *state) { return state->stack_info.type == STACK_TYPE_UNKNOWN; } -static inline -void unwind_start(struct unwind_state *state, struct task_struct *task, - struct pt_regs *regs, unsigned long *first_frame) -{ - first_frame = first_frame ? : get_stack_pointer(task, regs); - - __unwind_start(state, task, regs, first_frame); -} - static inline bool unwind_error(struct unwind_state *state) { return state->error; } -#ifdef CONFIG_FRAME_POINTER - static inline -unsigned long *unwind_get_return_address_ptr(struct unwind_state *state) +void unwind_start(struct unwind_state *state, struct task_struct *task, + struct pt_regs *regs, unsigned long *first_frame) { - if (unwind_done(state)) - return NULL; + first_frame = first_frame ? : get_stack_pointer(task, regs); - return state->regs ? &state->regs->ip : state->bp + 1; + __unwind_start(state, task, regs, first_frame); } +#if defined(CONFIG_ORC_UNWINDER) || defined(CONFIG_FRAME_POINTER_UNWINDER) static inline struct pt_regs *unwind_get_entry_regs(struct unwind_state *state) { if (unwind_done(state)) @@ -66,20 +58,46 @@ static inline struct pt_regs *unwind_get_entry_regs(struct unwind_state *state) return state->regs; } - -#else /* !CONFIG_FRAME_POINTER */ - -static inline -unsigned long *unwind_get_return_address_ptr(struct unwind_state *state) +#else +static inline struct pt_regs *unwind_get_entry_regs(struct unwind_state *state) { return NULL; } +#endif -static inline struct pt_regs *unwind_get_entry_regs(struct unwind_state *state) +#ifdef CONFIG_ORC_UNWINDER +void unwind_init(void); +void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size, + void *orc, size_t orc_size); +#else +static inline void unwind_init(void) {} +static inline +void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size, + void *orc, size_t orc_size) {} +#endif + +/* + * This disables KASAN checking when reading a value from another task's stack, + * since the other task could be running on another CPU and could have poisoned + * the stack in the meantime. + */ +#define READ_ONCE_TASK_STACK(task, x) \ +({ \ + unsigned long val; \ + if (task == current) \ + val = READ_ONCE(x); \ + else \ + val = READ_ONCE_NOCHECK(x); \ + val; \ +}) + +static inline bool task_on_another_cpu(struct task_struct *task) { - return NULL; +#ifdef CONFIG_SMP + return task != current && task->on_cpu; +#else + return false; +#endif } -#endif /* CONFIG_FRAME_POINTER */ - #endif /* _ASM_X86_UNWIND_H */ diff --git a/arch/x86/include/asm/unwind_hints.h b/arch/x86/include/asm/unwind_hints.h new file mode 100644 index 000000000000..bae46fc6b9de --- /dev/null +++ b/arch/x86/include/asm/unwind_hints.h @@ -0,0 +1,105 @@ +#ifndef _ASM_X86_UNWIND_HINTS_H +#define _ASM_X86_UNWIND_HINTS_H + +#include "orc_types.h" + +#ifdef __ASSEMBLY__ + +/* + * In asm, there are two kinds of code: normal C-type callable functions and + * the rest. The normal callable functions can be called by other code, and + * don't do anything unusual with the stack. Such normal callable functions + * are annotated with the ENTRY/ENDPROC macros. Most asm code falls in this + * category. In this case, no special debugging annotations are needed because + * objtool can automatically generate the ORC data for the ORC unwinder to read + * at runtime. + * + * Anything which doesn't fall into the above category, such as syscall and + * interrupt handlers, tends to not be called directly by other functions, and + * often does unusual non-C-function-type things with the stack pointer. Such + * code needs to be annotated such that objtool can understand it. The + * following CFI hint macros are for this type of code. + * + * These macros provide hints to objtool about the state of the stack at each + * instruction. Objtool starts from the hints and follows the code flow, + * making automatic CFI adjustments when it sees pushes and pops, filling out + * the debuginfo as necessary. It will also warn if it sees any + * inconsistencies. + */ +.macro UNWIND_HINT sp_reg=ORC_REG_SP sp_offset=0 type=ORC_TYPE_CALL +#ifdef CONFIG_STACK_VALIDATION +.Lunwind_hint_ip_\@: + .pushsection .discard.unwind_hints + /* struct unwind_hint */ + .long .Lunwind_hint_ip_\@ - . + .short \sp_offset + .byte \sp_reg + .byte \type + .popsection +#endif +.endm + +.macro UNWIND_HINT_EMPTY + UNWIND_HINT sp_reg=ORC_REG_UNDEFINED +.endm + +.macro UNWIND_HINT_REGS base=%rsp offset=0 indirect=0 extra=1 iret=0 + .if \base == %rsp + .if \indirect + .set sp_reg, ORC_REG_SP_INDIRECT + .else + .set sp_reg, ORC_REG_SP + .endif + .elseif \base == %rbp + .set sp_reg, ORC_REG_BP + .elseif \base == %rdi + .set sp_reg, ORC_REG_DI + .elseif \base == %rdx + .set sp_reg, ORC_REG_DX + .elseif \base == %r10 + .set sp_reg, ORC_REG_R10 + .else + .error "UNWIND_HINT_REGS: bad base register" + .endif + + .set sp_offset, \offset + + .if \iret + .set type, ORC_TYPE_REGS_IRET + .elseif \extra == 0 + .set type, ORC_TYPE_REGS_IRET + .set sp_offset, \offset + (16*8) + .else + .set type, ORC_TYPE_REGS + .endif + + UNWIND_HINT sp_reg=sp_reg sp_offset=sp_offset type=type +.endm + +.macro UNWIND_HINT_IRET_REGS base=%rsp offset=0 + UNWIND_HINT_REGS base=\base offset=\offset iret=1 +.endm + +.macro UNWIND_HINT_FUNC sp_offset=8 + UNWIND_HINT sp_offset=\sp_offset +.endm + +#else /* !__ASSEMBLY__ */ + +#define UNWIND_HINT(sp_reg, sp_offset, type) \ + "987: \n\t" \ + ".pushsection .discard.unwind_hints\n\t" \ + /* struct unwind_hint */ \ + ".long 987b - .\n\t" \ + ".short " __stringify(sp_offset) "\n\t" \ + ".byte " __stringify(sp_reg) "\n\t" \ + ".byte " __stringify(type) "\n\t" \ + ".popsection\n\t" + +#define UNWIND_HINT_SAVE UNWIND_HINT(0, 0, UNWIND_HINT_TYPE_SAVE) + +#define UNWIND_HINT_RESTORE UNWIND_HINT(0, 0, UNWIND_HINT_TYPE_RESTORE) + +#endif /* __ASSEMBLY__ */ + +#endif /* _ASM_X86_UNWIND_HINTS_H */ diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h index ddef37b16af2..66b8f93333d1 100644 --- a/arch/x86/include/uapi/asm/bootparam.h +++ b/arch/x86/include/uapi/asm/bootparam.h @@ -201,7 +201,7 @@ struct boot_params { * * @X86_SUBARCH_PC: Should be used if the hardware is enumerable using standard * PC mechanisms (PCI, ACPI) and doesn't need a special boot flow. - * @X86_SUBARCH_LGUEST: Used for x86 hypervisor demo, lguest + * @X86_SUBARCH_LGUEST: Used for x86 hypervisor demo, lguest, deprecated * @X86_SUBARCH_XEN: Used for Xen guest types which follow the PV boot path, * which start at asm startup_xen() entry point and later jump to the C * xen_start_kernel() entry point. Both domU and dom0 type of guests are diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index a01892bdd61a..287eac7d207f 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -126,11 +126,9 @@ obj-$(CONFIG_PERF_EVENTS) += perf_regs.o obj-$(CONFIG_TRACING) += tracepoint.o obj-$(CONFIG_SCHED_MC_PRIO) += itmt.o -ifdef CONFIG_FRAME_POINTER -obj-y += unwind_frame.o -else -obj-y += unwind_guess.o -endif +obj-$(CONFIG_ORC_UNWINDER) += unwind_orc.o +obj-$(CONFIG_FRAME_POINTER_UNWINDER) += unwind_frame.o +obj-$(CONFIG_GUESS_UNWINDER) += unwind_guess.o ### # 64 bit specific files diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 32e14d137416..3344d3382e91 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -742,7 +742,16 @@ static void *bp_int3_handler, *bp_int3_addr; int poke_int3_handler(struct pt_regs *regs) { - /* bp_patching_in_progress */ + /* + * Having observed our INT3 instruction, we now must observe + * bp_patching_in_progress. + * + * in_progress = TRUE INT3 + * WMB RMB + * write INT3 if (in_progress) + * + * Idem for bp_int3_handler. + */ smp_rmb(); if (likely(!bp_patching_in_progress)) @@ -788,9 +797,8 @@ void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler) bp_int3_addr = (u8 *)addr + sizeof(int3); bp_patching_in_progress = true; /* - * Corresponding read barrier in int3 notifier for - * making sure the in_progress flags is correctly ordered wrt. - * patching + * Corresponding read barrier in int3 notifier for making sure the + * in_progress and handler are correctly ordered wrt. patching. */ smp_wmb(); @@ -815,9 +823,11 @@ void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler) text_poke(addr, opcode, sizeof(int3)); on_each_cpu(do_sync_core, NULL, 1); - + /* + * sync_core() implies an smp_mb() and orders this store against + * the writing of the new instruction. + */ bp_patching_in_progress = false; - smp_wmb(); return addr; } diff --git a/arch/x86/kernel/asm-offsets_32.c b/arch/x86/kernel/asm-offsets_32.c index 880aa093268d..710edab9e644 100644 --- a/arch/x86/kernel/asm-offsets_32.c +++ b/arch/x86/kernel/asm-offsets_32.c @@ -4,9 +4,6 @@ #include <asm/ucontext.h> -#include <linux/lguest.h> -#include "../../../drivers/lguest/lg.h" - #define __SYSCALL_I386(nr, sym, qual) [nr] = 1, static char syscalls[] = { #include <asm/syscalls_32.h> @@ -62,23 +59,6 @@ void foo(void) OFFSET(stack_canary_offset, stack_canary, canary); #endif -#if defined(CONFIG_LGUEST) || defined(CONFIG_LGUEST_GUEST) || defined(CONFIG_LGUEST_MODULE) - BLANK(); - OFFSET(LGUEST_DATA_irq_enabled, lguest_data, irq_enabled); - OFFSET(LGUEST_DATA_irq_pending, lguest_data, irq_pending); - - BLANK(); - OFFSET(LGUEST_PAGES_host_gdt_desc, lguest_pages, state.host_gdt_desc); - OFFSET(LGUEST_PAGES_host_idt_desc, lguest_pages, state.host_idt_desc); - OFFSET(LGUEST_PAGES_host_cr3, lguest_pages, state.host_cr3); - OFFSET(LGUEST_PAGES_host_sp, lguest_pages, state.host_sp); - OFFSET(LGUEST_PAGES_guest_gdt_desc, lguest_pages,state.guest_gdt_desc); - OFFSET(LGUEST_PAGES_guest_idt_desc, lguest_pages,state.guest_idt_desc); - OFFSET(LGUEST_PAGES_guest_gdt, lguest_pages, state.guest_gdt); - OFFSET(LGUEST_PAGES_regs_trapnum, lguest_pages, regs.trapnum); - OFFSET(LGUEST_PAGES_regs_errcode, lguest_pages, regs.errcode); - OFFSET(LGUEST_PAGES_regs, lguest_pages, regs); -#endif BLANK(); DEFINE(__NR_syscall_max, sizeof(syscalls) - 1); DEFINE(NR_syscalls, sizeof(syscalls)); diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c index dbce3cca94cb..f13b4c00a5de 100644 --- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -94,6 +94,9 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs, if (stack_name) printk("%s <%s>\n", log_lvl, stack_name); + if (regs && on_stack(&stack_info, regs, sizeof(*regs))) + __show_regs(regs, 0); + /* * Scan the stack, printing any text addresses we find. At the * same time, follow proper stack frames with the unwinder. @@ -118,10 +121,8 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs, * Don't print regs->ip again if it was already printed * by __show_regs() below. */ - if (regs && stack == ®s->ip) { - unwind_next_frame(&state); - continue; - } + if (regs && stack == ®s->ip) + goto next; if (stack == ret_addr_p) reliable = 1; @@ -144,6 +145,7 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs, if (!reliable) continue; +next: /* * Get the next frame from the unwinder. No need to * check for an error: if anything goes wrong, the rest @@ -153,7 +155,7 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs, /* if the frame has entry regs, print them */ regs = unwind_get_entry_regs(&state); - if (regs) + if (regs && on_stack(&stack_info, regs, sizeof(*regs))) __show_regs(regs, 0); } @@ -265,7 +267,7 @@ int __die(const char *str, struct pt_regs *regs, long err) #ifdef CONFIG_X86_32 if (user_mode(regs)) { sp = regs->sp; - ss = regs->ss & 0xffff; + ss = regs->ss; } else { sp = kernel_stack_pointer(regs); savesegment(ss, ss); diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c index e5f0b40e66d2..4f0481474903 100644 --- a/arch/x86/kernel/dumpstack_32.c +++ b/arch/x86/kernel/dumpstack_32.c @@ -37,7 +37,7 @@ static bool in_hardirq_stack(unsigned long *stack, struct stack_info *info) * This is a software stack, so 'end' can be a valid stack pointer. * It just means the stack is empty. */ - if (stack < begin || stack > end) + if (stack <= begin || stack > end) return false; info->type = STACK_TYPE_IRQ; @@ -62,7 +62,7 @@ static bool in_softirq_stack(unsigned long *stack, struct stack_info *info) * This is a software stack, so 'end' can be a valid stack pointer. * It just means the stack is empty. */ - if (stack < begin || stack > end) + if (stack <= begin || stack > end) return false; info->type = STACK_TYPE_SOFTIRQ; diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c index 3e1471d57487..225af4184f06 100644 --- a/arch/x86/kernel/dumpstack_64.c +++ b/arch/x86/kernel/dumpstack_64.c @@ -55,7 +55,7 @@ static bool in_exception_stack(unsigned long *stack, struct stack_info *info) begin = end - (exception_stack_sizes[k] / sizeof(long)); regs = (struct pt_regs *)end - 1; - if (stack < begin || stack >= end) + if (stack <= begin || stack >= end) continue; info->type = STACK_TYPE_EXCEPTION + k; @@ -78,7 +78,7 @@ static bool in_irq_stack(unsigned long *stack, struct stack_info *info) * This is a software stack, so 'end' can be a valid stack pointer. * It just means the stack is empty. */ - if (stack < begin || stack > end) + if (stack <= begin || stack > end) return false; info->type = STACK_TYPE_IRQ; diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S index 1f85ee8f9439..29da9599fec0 100644 --- a/arch/x86/kernel/head_32.S +++ b/arch/x86/kernel/head_32.S @@ -155,7 +155,6 @@ ENTRY(startup_32) jmp *%eax .Lbad_subarch: -WEAK(lguest_entry) WEAK(xen_entry) /* Unknown implementation; there's really nothing we can do at this point. */ @@ -165,7 +164,6 @@ WEAK(xen_entry) subarch_entries: .long .Ldefault_entry /* normal x86/PC */ - .long lguest_entry /* lguest hypervisor */ .long xen_entry /* Xen hypervisor */ .long .Ldefault_entry /* Moorestown MID */ num_subarch_entries = (. - subarch_entries) / 4 @@ -457,12 +455,9 @@ early_idt_handler_common: /* The vector number is in pt_regs->gs */ cld - pushl %fs /* pt_regs->fs */ - movw $0, 2(%esp) /* clear high bits (some CPUs leave garbage) */ - pushl %es /* pt_regs->es */ - movw $0, 2(%esp) /* clear high bits (some CPUs leave garbage) */ - pushl %ds /* pt_regs->ds */ - movw $0, 2(%esp) /* clear high bits (some CPUs leave garbage) */ + pushl %fs /* pt_regs->fs (__fsh varies by model) */ + pushl %es /* pt_regs->es (__esh varies by model) */ + pushl %ds /* pt_regs->ds (__dsh varies by model) */ pushl %eax /* pt_regs->ax */ pushl %ebp /* pt_regs->bp */ pushl %edi /* pt_regs->di */ @@ -479,9 +474,8 @@ early_idt_handler_common: /* Load the vector number into EDX */ movl PT_GS(%esp), %edx - /* Load GS into pt_regs->gs and clear high bits */ + /* Load GS into pt_regs->gs (and maybe clobber __gsh) */ movw %gs, PT_GS(%esp) - movw $0, PT_GS+2(%esp) movl %esp, %eax /* args are pt_regs (EAX), trapnr (EDX) */ call early_fixup_exception @@ -493,10 +487,10 @@ early_idt_handler_common: popl %edi /* pt_regs->di */ popl %ebp /* pt_regs->bp */ popl %eax /* pt_regs->ax */ - popl %ds /* pt_regs->ds */ - popl %es /* pt_regs->es */ - popl %fs /* pt_regs->fs */ - popl %gs /* pt_regs->gs */ + popl %ds /* pt_regs->ds (always ignores __dsh) */ + popl %es /* pt_regs->es (always ignores __esh) */ + popl %fs /* pt_regs->fs (always ignores __fsh) */ + popl %gs /* pt_regs->gs (always ignores __gsh) */ decl %ss:early_recursion_flag addl $4, %esp /* pop pt_regs->orig_ax */ iret diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c index a870910c8565..f0e64db18ac8 100644 --- a/arch/x86/kernel/ldt.c +++ b/arch/x86/kernel/ldt.c @@ -21,6 +21,25 @@ #include <asm/mmu_context.h> #include <asm/syscalls.h> +static void refresh_ldt_segments(void) +{ +#ifdef CONFIG_X86_64 + unsigned short sel; + + /* + * Make sure that the cached DS and ES descriptors match the updated + * LDT. + */ + savesegment(ds, sel); + if ((sel & SEGMENT_TI_MASK) == SEGMENT_LDT) + loadsegment(ds, sel); + + savesegment(es, sel); + if ((sel & SEGMENT_TI_MASK) == SEGMENT_LDT) + loadsegment(es, sel); +#endif +} + /* context.lock is held for us, so we don't need any locking. */ static void flush_ldt(void *__mm) { @@ -32,6 +51,8 @@ static void flush_ldt(void *__mm) pc = &mm->context; set_ldt(pc->ldt->entries, pc->ldt->nr_entries); + + refresh_ldt_segments(); } /* The caller must call finalize_ldt_struct on the result. LDT starts zeroed. */ diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c index f67bd3205df7..62e7d70aadd5 100644 --- a/arch/x86/kernel/module.c +++ b/arch/x86/kernel/module.c @@ -35,6 +35,7 @@ #include <asm/page.h> #include <asm/pgtable.h> #include <asm/setup.h> +#include <asm/unwind.h> #if 0 #define DEBUGP(fmt, ...) \ @@ -213,7 +214,7 @@ int module_finalize(const Elf_Ehdr *hdr, struct module *me) { const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL, - *para = NULL; + *para = NULL, *orc = NULL, *orc_ip = NULL; char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) { @@ -225,6 +226,10 @@ int module_finalize(const Elf_Ehdr *hdr, locks = s; if (!strcmp(".parainstructions", secstrings + s->sh_name)) para = s; + if (!strcmp(".orc_unwind", secstrings + s->sh_name)) + orc = s; + if (!strcmp(".orc_unwind_ip", secstrings + s->sh_name)) + orc_ip = s; } if (alt) { @@ -248,6 +253,10 @@ int module_finalize(const Elf_Ehdr *hdr, /* make jump label nops */ jump_label_apply_nops(me); + if (orc && orc_ip) + unwind_module_init(me, (void *)orc_ip->sh_addr, orc_ip->sh_size, + (void *)orc->sh_addr, orc->sh_size); + return 0; } diff --git a/arch/x86/kernel/platform-quirks.c b/arch/x86/kernel/platform-quirks.c index 91271122f0df..502a77d0adb0 100644 --- a/arch/x86/kernel/platform-quirks.c +++ b/arch/x86/kernel/platform-quirks.c @@ -16,7 +16,6 @@ void __init x86_early_init_platform_quirks(void) x86_platform.legacy.reserve_bios_regions = 1; break; case X86_SUBARCH_XEN: - case X86_SUBARCH_LGUEST: x86_platform.legacy.devices.pnpbios = 0; x86_platform.legacy.rtc = 0; break; diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index c6d6dc5f8bb2..efc5eeb58292 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -68,7 +68,7 @@ void __show_regs(struct pt_regs *regs, int all) if (user_mode(regs)) { sp = regs->sp; - ss = regs->ss & 0xffff; + ss = regs->ss; gs = get_user_gs(regs); } else { sp = kernel_stack_pointer(regs); diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index c3169be4c596..c85269a76511 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -69,8 +69,7 @@ void __show_regs(struct pt_regs *regs, int all) unsigned int fsindex, gsindex; unsigned int ds, cs, es; - printk(KERN_DEFAULT "RIP: %04lx:%pS\n", regs->cs & 0xffff, - (void *)regs->ip); + printk(KERN_DEFAULT "RIP: %04lx:%pS\n", regs->cs, (void *)regs->ip); printk(KERN_DEFAULT "RSP: %04lx:%016lx EFLAGS: %08lx", regs->ss, regs->sp, regs->flags); if (regs->orig_ax != -1) @@ -149,6 +148,123 @@ void release_thread(struct task_struct *dead_task) } } +enum which_selector { + FS, + GS +}; + +/* + * Saves the FS or GS base for an outgoing thread if FSGSBASE extensions are + * not available. The goal is to be reasonably fast on non-FSGSBASE systems. + * It's forcibly inlined because it'll generate better code and this function + * is hot. + */ +static __always_inline void save_base_legacy(struct task_struct *prev_p, + unsigned short selector, + enum which_selector which) +{ + if (likely(selector == 0)) { + /* + * On Intel (without X86_BUG_NULL_SEG), the segment base could + * be the pre-existing saved base or it could be zero. On AMD + * (with X86_BUG_NULL_SEG), the segment base could be almost + * anything. + * + * This branch is very hot (it's hit twice on almost every + * context switch between 64-bit programs), and avoiding + * the RDMSR helps a lot, so we just assume that whatever + * value is already saved is correct. This matches historical + * Linux behavior, so it won't break existing applications. + * + * To avoid leaking state, on non-X86_BUG_NULL_SEG CPUs, if we + * report that the base is zero, it needs to actually be zero: + * see the corresponding logic in load_seg_legacy. + */ + } else { + /* + * If the selector is 1, 2, or 3, then the base is zero on + * !X86_BUG_NULL_SEG CPUs and could be anything on + * X86_BUG_NULL_SEG CPUs. In the latter case, Linux + * has never attempted to preserve the base across context + * switches. + * + * If selector > 3, then it refers to a real segment, and + * saving the base isn't necessary. + */ + if (which == FS) + prev_p->thread.fsbase = 0; + else + prev_p->thread.gsbase = 0; + } +} + +static __always_inline void save_fsgs(struct task_struct *task) +{ + savesegment(fs, task->thread.fsindex); + savesegment(gs, task->thread.gsindex); + save_base_legacy(task, task->thread.fsindex, FS); + save_base_legacy(task, task->thread.gsindex, GS); +} + +static __always_inline void loadseg(enum which_selector which, + unsigned short sel) +{ + if (which == FS) + loadsegment(fs, sel); + else + load_gs_index(sel); +} + +static __always_inline void load_seg_legacy(unsigned short prev_index, + unsigned long prev_base, + unsigned short next_index, + unsigned long next_base, + enum which_selector which) +{ + if (likely(next_index <= 3)) { + /* + * The next task is using 64-bit TLS, is not using this + * segment at all, or is having fun with arcane CPU features. + */ + if (next_base == 0) { + /* + * Nasty case: on AMD CPUs, we need to forcibly zero + * the base. + */ + if (static_cpu_has_bug(X86_BUG_NULL_SEG)) { + loadseg(which, __USER_DS); + loadseg(which, next_index); + } else { + /* + * We could try to exhaustively detect cases + * under which we can skip the segment load, + * but there's really only one case that matters + * for performance: if both the previous and + * next states are fully zeroed, we can skip + * the load. + * + * (This assumes that prev_base == 0 has no + * false positives. This is the case on + * Intel-style CPUs.) + */ + if (likely(prev_index | next_index | prev_base)) + loadseg(which, next_index); + } + } else { + if (prev_index != next_index) + loadseg(which, next_index); + wrmsrl(which == FS ? MSR_FS_BASE : MSR_KERNEL_GS_BASE, + next_base); + } + } else { + /* + * The next task is using a real segment. Loading the selector + * is sufficient. + */ + loadseg(which, next_index); + } +} + int copy_thread_tls(unsigned long clone_flags, unsigned long sp, unsigned long arg, struct task_struct *p, unsigned long tls) { @@ -229,10 +345,19 @@ start_thread_common(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp, unsigned int _cs, unsigned int _ss, unsigned int _ds) { + WARN_ON_ONCE(regs != current_pt_regs()); + + if (static_cpu_has(X86_BUG_NULL_SEG)) { + /* Loading zero below won't clear the base. */ + loadsegment(fs, __USER_DS); + load_gs_index(__USER_DS); + } + loadsegment(fs, 0); loadsegment(es, _ds); loadsegment(ds, _ds); load_gs_index(0); + regs->ip = new_ip; regs->sp = new_sp; regs->cs = _cs; @@ -277,7 +402,9 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) struct fpu *next_fpu = &next->fpu; int cpu = smp_processor_id(); struct tss_struct *tss = &per_cpu(cpu_tss, cpu); - unsigned prev_fsindex, prev_gsindex; + + WARN_ON_ONCE(IS_ENABLED(CONFIG_DEBUG_ENTRY) && + this_cpu_read(irq_count) != -1); switch_fpu_prepare(prev_fpu, cpu); @@ -286,8 +413,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) * * (e.g. xen_load_tls()) */ - savesegment(fs, prev_fsindex); - savesegment(gs, prev_gsindex); + save_fsgs(prev_p); /* * Load TLS before restoring any segments so that segment loads @@ -326,108 +452,10 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) if (unlikely(next->ds | prev->ds)) loadsegment(ds, next->ds); - /* - * Switch FS and GS. - * - * These are even more complicated than DS and ES: they have - * 64-bit bases are that controlled by arch_prctl. The bases - * don't necessarily match the selectors, as user code can do - * any number of things to cause them to be inconsistent. - * - * We don't promise to preserve the bases if the selectors are - * nonzero. We also don't promise to preserve the base if the - * selector is zero and the base doesn't match whatever was - * most recently passed to ARCH_SET_FS/GS. (If/when the - * FSGSBASE instructions are enabled, we'll need to offer - * stronger guarantees.) - * - * As an invariant, - * (fsbase != 0 && fsindex != 0) || (gsbase != 0 && gsindex != 0) is - * impossible. - */ - if (next->fsindex) { - /* Loading a nonzero value into FS sets the index and base. */ - loadsegment(fs, next->fsindex); - } else { - if (next->fsbase) { - /* Next index is zero but next base is nonzero. */ - if (prev_fsindex) - loadsegment(fs, 0); - wrmsrl(MSR_FS_BASE, next->fsbase); - } else { - /* Next base and index are both zero. */ - if (static_cpu_has_bug(X86_BUG_NULL_SEG)) { - /* - * We don't know the previous base and can't - * find out without RDMSR. Forcibly clear it. - */ - loadsegment(fs, __USER_DS); - loadsegment(fs, 0); - } else { - /* - * If the previous index is zero and ARCH_SET_FS - * didn't change the base, then the base is - * also zero and we don't need to do anything. - */ - if (prev->fsbase || prev_fsindex) - loadsegment(fs, 0); - } - } - } - /* - * Save the old state and preserve the invariant. - * NB: if prev_fsindex == 0, then we can't reliably learn the base - * without RDMSR because Intel user code can zero it without telling - * us and AMD user code can program any 32-bit value without telling - * us. - */ - if (prev_fsindex) - prev->fsbase = 0; - prev->fsindex = prev_fsindex; - - if (next->gsindex) { - /* Loading a nonzero value into GS sets the index and base. */ - load_gs_index(next->gsindex); - } else { - if (next->gsbase) { - /* Next index is zero but next base is nonzero. */ - if (prev_gsindex) - load_gs_index(0); - wrmsrl(MSR_KERNEL_GS_BASE, next->gsbase); - } else { - /* Next base and index are both zero. */ - if (static_cpu_has_bug(X86_BUG_NULL_SEG)) { - /* - * We don't know the previous base and can't - * find out without RDMSR. Forcibly clear it. - * - * This contains a pointless SWAPGS pair. - * Fixing it would involve an explicit check - * for Xen or a new pvop. - */ - load_gs_index(__USER_DS); - load_gs_index(0); - } else { - /* - * If the previous index is zero and ARCH_SET_GS - * didn't change the base, then the base is - * also zero and we don't need to do anything. - */ - if (prev->gsbase || prev_gsindex) - load_gs_index(0); - } - } - } - /* - * Save the old state and preserve the invariant. - * NB: if prev_gsindex == 0, then we can't reliably learn the base - * without RDMSR because Intel user code can zero it without telling - * us and AMD user code can program any 32-bit value without telling - * us. - */ - if (prev_gsindex) - prev->gsbase = 0; - prev->gsindex = prev_gsindex; + load_seg_legacy(prev->fsindex, prev->fsbase, + next->fsindex, next->fsbase, FS); + load_seg_legacy(prev->gsindex, prev->gsbase, + next->gsindex, next->gsbase, GS); switch_fpu_finish(next_fpu, cpu); diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 3486d0498800..ecab32282f0f 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -115,6 +115,7 @@ #include <asm/microcode.h> #include <asm/mmu_context.h> #include <asm/kaslr.h> +#include <asm/unwind.h> /* * max_low_pfn_mapped: highest direct mapped pfn under 4GB @@ -1310,6 +1311,8 @@ void __init setup_arch(char **cmdline_p) if (efi_enabled(EFI_BOOT)) efi_apply_memmap_quirks(); #endif + + unwind_init(); } #ifdef CONFIG_X86_32 diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index cc30a74e4adb..e04442345fc0 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -256,7 +256,7 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size, sp = current->sas_ss_sp + current->sas_ss_size; } else if (IS_ENABLED(CONFIG_X86_32) && !onsigstack && - (regs->ss & 0xffff) != __USER_DS && + regs->ss != __USER_DS && !(ka->sa.sa_flags & SA_RESTORER) && ka->sa.sa_restorer) { /* This is the legacy signal stack switching. */ diff --git a/arch/x86/kernel/step.c b/arch/x86/kernel/step.c index 5f25cfbd952e..5ee663836c08 100644 --- a/arch/x86/kernel/step.c +++ b/arch/x86/kernel/step.c @@ -13,7 +13,7 @@ unsigned long convert_ip_to_linear(struct task_struct *child, struct pt_regs *re unsigned long addr, seg; addr = regs->ip; - seg = regs->cs & 0xffff; + seg = regs->cs; if (v8086_mode(regs)) { addr = (addr & 0xffff) + (seg << 4); return addr; diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c index c29e5bc7e9c9..d145a0b1f529 100644 --- a/arch/x86/kernel/unwind_frame.c +++ b/arch/x86/kernel/unwind_frame.c @@ -10,20 +10,22 @@ #define FRAME_HEADER_SIZE (sizeof(long) * 2) -/* - * This disables KASAN checking when reading a value from another task's stack, - * since the other task could be running on another CPU and could have poisoned - * the stack in the meantime. - */ -#define READ_ONCE_TASK_STACK(task, x) \ -({ \ - unsigned long val; \ - if (task == current) \ - val = READ_ONCE(x); \ - else \ - val = READ_ONCE_NOCHECK(x); \ - val; \ -}) +unsigned long unwind_get_return_address(struct unwind_state *state) +{ + if (unwind_done(state)) + return 0; + + return __kernel_text_address(state->ip) ? state->ip : 0; +} +EXPORT_SYMBOL_GPL(unwind_get_return_address); + +unsigned long *unwind_get_return_address_ptr(struct unwind_state *state) +{ + if (unwind_done(state)) + return NULL; + + return state->regs ? &state->regs->ip : state->bp + 1; +} static void unwind_dump(struct unwind_state *state) { @@ -66,15 +68,6 @@ static void unwind_dump(struct unwind_state *state) } } -unsigned long unwind_get_return_address(struct unwind_state *state) -{ - if (unwind_done(state)) - return 0; - - return __kernel_text_address(state->ip) ? state->ip : 0; -} -EXPORT_SYMBOL_GPL(unwind_get_return_address); - static size_t regs_size(struct pt_regs *regs) { /* x86_32 regs from kernel mode are two words shorter: */ diff --git a/arch/x86/kernel/unwind_guess.c b/arch/x86/kernel/unwind_guess.c index 039f36738e49..4f0e17b90463 100644 --- a/arch/x86/kernel/unwind_guess.c +++ b/arch/x86/kernel/unwind_guess.c @@ -19,6 +19,11 @@ unsigned long unwind_get_return_address(struct unwind_state *state) } EXPORT_SYMBOL_GPL(unwind_get_return_address); +unsigned long *unwind_get_return_address_ptr(struct unwind_state *state) +{ + return NULL; +} + bool unwind_next_frame(struct unwind_state *state) { struct stack_info *info = &state->stack_info; diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c new file mode 100644 index 000000000000..570b70d3f604 --- /dev/null +++ b/arch/x86/kernel/unwind_orc.c @@ -0,0 +1,582 @@ +#include <linux/module.h> +#include <linux/sort.h> +#include <asm/ptrace.h> +#include <asm/stacktrace.h> +#include <asm/unwind.h> +#include <asm/orc_types.h> +#include <asm/orc_lookup.h> +#include <asm/sections.h> + +#define orc_warn(fmt, ...) \ + printk_deferred_once(KERN_WARNING pr_fmt("WARNING: " fmt), ##__VA_ARGS__) + +extern int __start_orc_unwind_ip[]; +extern int __stop_orc_unwind_ip[]; +extern struct orc_entry __start_orc_unwind[]; +extern struct orc_entry __stop_orc_unwind[]; + +static DEFINE_MUTEX(sort_mutex); +int *cur_orc_ip_table = __start_orc_unwind_ip; +struct orc_entry *cur_orc_table = __start_orc_unwind; + +unsigned int lookup_num_blocks; +bool orc_init; + +static inline unsigned long orc_ip(const int *ip) +{ + return (unsigned long)ip + *ip; +} + +static struct orc_entry *__orc_find(int *ip_table, struct orc_entry *u_table, + unsigned int num_entries, unsigned long ip) +{ + int *first = ip_table; + int *last = ip_table + num_entries - 1; + int *mid = first, *found = first; + + if (!num_entries) + return NULL; + + /* + * Do a binary range search to find the rightmost duplicate of a given + * starting address. Some entries are section terminators which are + * "weak" entries for ensuring there are no gaps. They should be + * ignored when they conflict with a real entry. + */ + while (first <= last) { + mid = first + ((last - first) / 2); + + if (orc_ip(mid) <= ip) { + found = mid; + first = mid + 1; + } else + last = mid - 1; + } + + return u_table + (found - ip_table); +} + +#ifdef CONFIG_MODULES +static struct orc_entry *orc_module_find(unsigned long ip) +{ + struct module *mod; + + mod = __module_address(ip); + if (!mod || !mod->arch.orc_unwind || !mod->arch.orc_unwind_ip) + return NULL; + return __orc_find(mod->arch.orc_unwind_ip, mod->arch.orc_unwind, + mod->arch.num_orcs, ip); +} +#else +static struct orc_entry *orc_module_find(unsigned long ip) +{ + return NULL; +} +#endif + +static struct orc_entry *orc_find(unsigned long ip) +{ + if (!orc_init) + return NULL; + + /* For non-init vmlinux addresses, use the fast lookup table: */ + if (ip >= LOOKUP_START_IP && ip < LOOKUP_STOP_IP) { + unsigned int idx, start, stop; + + idx = (ip - LOOKUP_START_IP) / LOOKUP_BLOCK_SIZE; + + if (unlikely((idx >= lookup_num_blocks-1))) { + orc_warn("WARNING: bad lookup idx: idx=%u num=%u ip=%lx\n", + idx, lookup_num_blocks, ip); + return NULL; + } + + start = orc_lookup[idx]; + stop = orc_lookup[idx + 1] + 1; + + if (unlikely((__start_orc_unwind + start >= __stop_orc_unwind) || + (__start_orc_unwind + stop > __stop_orc_unwind))) { + orc_warn("WARNING: bad lookup value: idx=%u num=%u start=%u stop=%u ip=%lx\n", + idx, lookup_num_blocks, start, stop, ip); + return NULL; + } + + return __orc_find(__start_orc_unwind_ip + start, + __start_orc_unwind + start, stop - start, ip); + } + + /* vmlinux .init slow lookup: */ + if (ip >= (unsigned long)_sinittext && ip < (unsigned long)_einittext) + return __orc_find(__start_orc_unwind_ip, __start_orc_unwind, + __stop_orc_unwind_ip - __start_orc_unwind_ip, ip); + + /* Module lookup: */ + return orc_module_find(ip); +} + +static void orc_sort_swap(void *_a, void *_b, int size) +{ + struct orc_entry *orc_a, *orc_b; + struct orc_entry orc_tmp; + int *a = _a, *b = _b, tmp; + int delta = _b - _a; + + /* Swap the .orc_unwind_ip entries: */ + tmp = *a; + *a = *b + delta; + *b = tmp - delta; + + /* Swap the corresponding .orc_unwind entries: */ + orc_a = cur_orc_table + (a - cur_orc_ip_table); + orc_b = cur_orc_table + (b - cur_orc_ip_table); + orc_tmp = *orc_a; + *orc_a = *orc_b; + *orc_b = orc_tmp; +} + +static int orc_sort_cmp(const void *_a, const void *_b) +{ + struct orc_entry *orc_a; + const int *a = _a, *b = _b; + unsigned long a_val = orc_ip(a); + unsigned long b_val = orc_ip(b); + + if (a_val > b_val) + return 1; + if (a_val < b_val) + return -1; + + /* + * The "weak" section terminator entries need to always be on the left + * to ensure the lookup code skips them in favor of real entries. + * These terminator entries exist to handle any gaps created by + * whitelisted .o files which didn't get objtool generation. + */ + orc_a = cur_orc_table + (a - cur_orc_ip_table); + return orc_a->sp_reg == ORC_REG_UNDEFINED ? -1 : 1; +} + +#ifdef CONFIG_MODULES +void unwind_module_init(struct module *mod, void *_orc_ip, size_t orc_ip_size, + void *_orc, size_t orc_size) +{ + int *orc_ip = _orc_ip; + struct orc_entry *orc = _orc; + unsigned int num_entries = orc_ip_size / sizeof(int); + + WARN_ON_ONCE(orc_ip_size % sizeof(int) != 0 || + orc_size % sizeof(*orc) != 0 || + num_entries != orc_size / sizeof(*orc)); + + /* + * The 'cur_orc_*' globals allow the orc_sort_swap() callback to + * associate an .orc_unwind_ip table entry with its corresponding + * .orc_unwind entry so they can both be swapped. + */ + mutex_lock(&sort_mutex); + cur_orc_ip_table = orc_ip; + cur_orc_table = orc; + sort(orc_ip, num_entries, sizeof(int), orc_sort_cmp, orc_sort_swap); + mutex_unlock(&sort_mutex); + + mod->arch.orc_unwind_ip = orc_ip; + mod->arch.orc_unwind = orc; + mod->arch.num_orcs = num_entries; +} +#endif + +void __init unwind_init(void) +{ + size_t orc_ip_size = (void *)__stop_orc_unwind_ip - (void *)__start_orc_unwind_ip; + size_t orc_size = (void *)__stop_orc_unwind - (void *)__start_orc_unwind; + size_t num_entries = orc_ip_size / sizeof(int); + struct orc_entry *orc; + int i; + + if (!num_entries || orc_ip_size % sizeof(int) != 0 || + orc_size % sizeof(struct orc_entry) != 0 || + num_entries != orc_size / sizeof(struct orc_entry)) { + orc_warn("WARNING: Bad or missing .orc_unwind table. Disabling unwinder.\n"); + return; + } + + /* Sort the .orc_unwind and .orc_unwind_ip tables: */ + sort(__start_orc_unwind_ip, num_entries, sizeof(int), orc_sort_cmp, + orc_sort_swap); + + /* Initialize the fast lookup table: */ + lookup_num_blocks = orc_lookup_end - orc_lookup; + for (i = 0; i < lookup_num_blocks-1; i++) { + orc = __orc_find(__start_orc_unwind_ip, __start_orc_unwind, + num_entries, + LOOKUP_START_IP + (LOOKUP_BLOCK_SIZE * i)); + if (!orc) { + orc_warn("WARNING: Corrupt .orc_unwind table. Disabling unwinder.\n"); + return; + } + + orc_lookup[i] = orc - __start_orc_unwind; + } + + /* Initialize the ending block: */ + orc = __orc_find(__start_orc_unwind_ip, __start_orc_unwind, num_entries, + LOOKUP_STOP_IP); + if (!orc) { + orc_warn("WARNING: Corrupt .orc_unwind table. Disabling unwinder.\n"); + return; + } + orc_lookup[lookup_num_blocks-1] = orc - __start_orc_unwind; + + orc_init = true; +} + +unsigned long unwind_get_return_address(struct unwind_state *state) +{ + if (unwind_done(state)) + return 0; + + return __kernel_text_address(state->ip) ? state->ip : 0; +} +EXPORT_SYMBOL_GPL(unwind_get_return_address); + +unsigned long *unwind_get_return_address_ptr(struct unwind_state *state) +{ + if (unwind_done(state)) + return NULL; + + if (state->regs) + return &state->regs->ip; + + if (state->sp) + return (unsigned long *)state->sp - 1; + + return NULL; +} + +static bool stack_access_ok(struct unwind_state *state, unsigned long addr, + size_t len) +{ + struct stack_info *info = &state->stack_info; + + /* + * If the address isn't on the current stack, switch to the next one. + * + * We may have to traverse multiple stacks to deal with the possibility + * that info->next_sp could point to an empty stack and the address + * could be on a subsequent stack. + */ + while (!on_stack(info, (void *)addr, len)) + if (get_stack_info(info->next_sp, state->task, info, + &state->stack_mask)) + return false; + + return true; +} + +static bool deref_stack_reg(struct unwind_state *state, unsigned long addr, + unsigned long *val) +{ + if (!stack_access_ok(state, addr, sizeof(long))) + return false; + + *val = READ_ONCE_TASK_STACK(state->task, *(unsigned long *)addr); + return true; +} + +#define REGS_SIZE (sizeof(struct pt_regs)) +#define SP_OFFSET (offsetof(struct pt_regs, sp)) +#define IRET_REGS_SIZE (REGS_SIZE - offsetof(struct pt_regs, ip)) +#define IRET_SP_OFFSET (SP_OFFSET - offsetof(struct pt_regs, ip)) + +static bool deref_stack_regs(struct unwind_state *state, unsigned long addr, + unsigned long *ip, unsigned long *sp, bool full) +{ + size_t regs_size = full ? REGS_SIZE : IRET_REGS_SIZE; + size_t sp_offset = full ? SP_OFFSET : IRET_SP_OFFSET; + struct pt_regs *regs = (struct pt_regs *)(addr + regs_size - REGS_SIZE); + + if (IS_ENABLED(CONFIG_X86_64)) { + if (!stack_access_ok(state, addr, regs_size)) + return false; + + *ip = regs->ip; + *sp = regs->sp; + + return true; + } + + if (!stack_access_ok(state, addr, sp_offset)) + return false; + + *ip = regs->ip; + + if (user_mode(regs)) { + if (!stack_access_ok(state, addr + sp_offset, + REGS_SIZE - SP_OFFSET)) + return false; + + *sp = regs->sp; + } else + *sp = (unsigned long)®s->sp; + + return true; +} + +bool unwind_next_frame(struct unwind_state *state) +{ + unsigned long ip_p, sp, orig_ip, prev_sp = state->sp; + enum stack_type prev_type = state->stack_info.type; + struct orc_entry *orc; + struct pt_regs *ptregs; + bool indirect = false; + + if (unwind_done(state)) + return false; + + /* Don't let modules unload while we're reading their ORC data. */ + preempt_disable(); + + /* Have we reached the end? */ + if (state->regs && user_mode(state->regs)) + goto done; + + /* + * Find the orc_entry associated with the text address. + * + * Decrement call return addresses by one so they work for sibling + * calls and calls to noreturn functions. + */ + orc = orc_find(state->signal ? state->ip : state->ip - 1); + if (!orc || orc->sp_reg == ORC_REG_UNDEFINED) + goto done; + orig_ip = state->ip; + + /* Find the previous frame's stack: */ + switch (orc->sp_reg) { + case ORC_REG_SP: + sp = state->sp + orc->sp_offset; + break; + + case ORC_REG_BP: + sp = state->bp + orc->sp_offset; + break; + + case ORC_REG_SP_INDIRECT: + sp = state->sp + orc->sp_offset; + indirect = true; + break; + + case ORC_REG_BP_INDIRECT: + sp = state->bp + orc->sp_offset; + indirect = true; + break; + + case ORC_REG_R10: + if (!state->regs || !state->full_regs) { + orc_warn("missing regs for base reg R10 at ip %p\n", + (void *)state->ip); + goto done; + } + sp = state->regs->r10; + break; + + case ORC_REG_R13: + if (!state->regs || !state->full_regs) { + orc_warn("missing regs for base reg R13 at ip %p\n", + (void *)state->ip); + goto done; + } + sp = state->regs->r13; + break; + + case ORC_REG_DI: + if (!state->regs || !state->full_regs) { + orc_warn("missing regs for base reg DI at ip %p\n", + (void *)state->ip); + goto done; + } + sp = state->regs->di; + break; + + case ORC_REG_DX: + if (!state->regs || !state->full_regs) { + orc_warn("missing regs for base reg DX at ip %p\n", + (void *)state->ip); + goto done; + } + sp = state->regs->dx; + break; + + default: + orc_warn("unknown SP base reg %d for ip %p\n", + orc->sp_reg, (void *)state->ip); + goto done; + } + + if (indirect) { + if (!deref_stack_reg(state, sp, &sp)) + goto done; + } + + /* Find IP, SP and possibly regs: */ + switch (orc->type) { + case ORC_TYPE_CALL: + ip_p = sp - sizeof(long); + + if (!deref_stack_reg(state, ip_p, &state->ip)) + goto done; + + state->ip = ftrace_graph_ret_addr(state->task, &state->graph_idx, + state->ip, (void *)ip_p); + + state->sp = sp; + state->regs = NULL; + state->signal = false; + break; + + case ORC_TYPE_REGS: + if (!deref_stack_regs(state, sp, &state->ip, &state->sp, true)) { + orc_warn("can't dereference registers at %p for ip %p\n", + (void *)sp, (void *)orig_ip); + goto done; + } + + state->regs = (struct pt_regs *)sp; + state->full_regs = true; + state->signal = true; + break; + + case ORC_TYPE_REGS_IRET: + if (!deref_stack_regs(state, sp, &state->ip, &state->sp, false)) { + orc_warn("can't dereference iret registers at %p for ip %p\n", + (void *)sp, (void *)orig_ip); + goto done; + } + + ptregs = container_of((void *)sp, struct pt_regs, ip); + if ((unsigned long)ptregs >= prev_sp && + on_stack(&state->stack_info, ptregs, REGS_SIZE)) { + state->regs = ptregs; + state->full_regs = false; + } else + state->regs = NULL; + + state->signal = true; + break; + + default: + orc_warn("unknown .orc_unwind entry type %d\n", orc->type); + break; + } + + /* Find BP: */ + switch (orc->bp_reg) { + case ORC_REG_UNDEFINED: + if (state->regs && state->full_regs) + state->bp = state->regs->bp; + break; + + case ORC_REG_PREV_SP: + if (!deref_stack_reg(state, sp + orc->bp_offset, &state->bp)) + goto done; + break; + + case ORC_REG_BP: + if (!deref_stack_reg(state, state->bp + orc->bp_offset, &state->bp)) + goto done; + break; + + default: + orc_warn("unknown BP base reg %d for ip %p\n", + orc->bp_reg, (void *)orig_ip); + goto done; + } + + /* Prevent a recursive loop due to bad ORC data: */ + if (state->stack_info.type == prev_type && + on_stack(&state->stack_info, (void *)state->sp, sizeof(long)) && + state->sp <= prev_sp) { + orc_warn("stack going in the wrong direction? ip=%p\n", + (void *)orig_ip); + goto done; + } + + preempt_enable(); + return true; + +done: + preempt_enable(); + state->stack_info.type = STACK_TYPE_UNKNOWN; + return false; +} +EXPORT_SYMBOL_GPL(unwind_next_frame); + +void __unwind_start(struct unwind_state *state, struct task_struct *task, + struct pt_regs *regs, unsigned long *first_frame) +{ + memset(state, 0, sizeof(*state)); + state->task = task; + + /* + * Refuse to unwind the stack of a task while it's executing on another + * CPU. This check is racy, but that's ok: the unwinder has other + * checks to prevent it from going off the rails. + */ + if (task_on_another_cpu(task)) + goto done; + + if (regs) { + if (user_mode(regs)) + goto done; + + state->ip = regs->ip; + state->sp = kernel_stack_pointer(regs); + state->bp = regs->bp; + state->regs = regs; + state->full_regs = true; + state->signal = true; + + } else if (task == current) { + asm volatile("lea (%%rip), %0\n\t" + "mov %%rsp, %1\n\t" + "mov %%rbp, %2\n\t" + : "=r" (state->ip), "=r" (state->sp), + "=r" (state->bp)); + + } else { + struct inactive_task_frame *frame = (void *)task->thread.sp; + + state->sp = task->thread.sp; + state->bp = READ_ONCE_NOCHECK(frame->bp); + state->ip = READ_ONCE_NOCHECK(frame->ret_addr); + } + + if (get_stack_info((unsigned long *)state->sp, state->task, + &state->stack_info, &state->stack_mask)) + return; + + /* + * The caller can provide the address of the first frame directly + * (first_frame) or indirectly (regs->sp) to indicate which stack frame + * to start unwinding at. Skip ahead until we reach it. + */ + + /* When starting from regs, skip the regs frame: */ + if (regs) { + unwind_next_frame(state); + return; + } + + /* Otherwise, skip ahead to the user-specified starting frame: */ + while (!unwind_done(state) && + (!on_stack(&state->stack_info, first_frame, sizeof(long)) || + state->sp <= (unsigned long)first_frame)) + unwind_next_frame(state); + + return; + +done: + state->stack_info.type = STACK_TYPE_UNKNOWN; + return; +} +EXPORT_SYMBOL_GPL(__unwind_start); diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index c8a3b61be0aa..f05f00acac89 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -24,6 +24,7 @@ #include <asm/asm-offsets.h> #include <asm/thread_info.h> #include <asm/page_types.h> +#include <asm/orc_lookup.h> #include <asm/cache.h> #include <asm/boot.h> @@ -148,6 +149,8 @@ SECTIONS BUG_TABLE + ORC_UNWIND_TABLE + . = ALIGN(PAGE_SIZE); __vvar_page = .; diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig index 2688c7dc5323..3ea624452f93 100644 --- a/arch/x86/kvm/Kconfig +++ b/arch/x86/kvm/Kconfig @@ -89,6 +89,5 @@ config KVM_MMU_AUDIT # OK, it's a little counter-intuitive to do this, but it puts it neatly under # the virtualization menu. source drivers/vhost/Kconfig -source drivers/lguest/Kconfig endif # VIRTUALIZATION diff --git a/arch/x86/lguest/Kconfig b/arch/x86/lguest/Kconfig deleted file mode 100644 index 08f41caada45..000000000000 --- a/arch/x86/lguest/Kconfig +++ /dev/null @@ -1,14 +0,0 @@ -config LGUEST_GUEST - bool "Lguest guest support" - depends on X86_32 && PARAVIRT && PCI - select TTY - select VIRTUALIZATION - select VIRTIO - select VIRTIO_CONSOLE - help - Lguest is a tiny in-kernel hypervisor. Selecting this will - allow your kernel to boot under lguest. This option will increase - your kernel size by about 10k. If in doubt, say N. - - If you say Y here, make sure you say Y (or M) to the virtio block - and net drivers which lguest needs. diff --git a/arch/x86/lguest/Makefile b/arch/x86/lguest/Makefile deleted file mode 100644 index 8f38d577a2fa..000000000000 --- a/arch/x86/lguest/Makefile +++ /dev/null @@ -1,2 +0,0 @@ -obj-y := head_32.o boot.o -CFLAGS_boot.o := $(call cc-option, -fno-stack-protector) diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c deleted file mode 100644 index 99472698c931..000000000000 --- a/arch/x86/lguest/boot.c +++ /dev/null @@ -1,1558 +0,0 @@ -/*P:010 - * A hypervisor allows multiple Operating Systems to run on a single machine. - * To quote David Wheeler: "Any problem in computer science can be solved with - * another layer of indirection." - * - * We keep things simple in two ways. First, we start with a normal Linux - * kernel and insert a module (lg.ko) which allows us to run other Linux - * kernels the same way we'd run processes. We call the first kernel the Host, - * and the others the Guests. The program which sets up and configures Guests - * (such as the example in tools/lguest/lguest.c) is called the Launcher. - * - * Secondly, we only run specially modified Guests, not normal kernels: setting - * CONFIG_LGUEST_GUEST to "y" compiles this file into the kernel so it knows - * how to be a Guest at boot time. This means that you can use the same kernel - * you boot normally (ie. as a Host) as a Guest. - * - * These Guests know that they cannot do privileged operations, such as disable - * interrupts, and that they have to ask the Host to do such things explicitly. - * This file consists of all the replacements for such low-level native - * hardware operations: these special Guest versions call the Host. - * - * So how does the kernel know it's a Guest? We'll see that later, but let's - * just say that we end up here where we replace the native functions various - * "paravirt" structures with our Guest versions, then boot like normal. -:*/ - -/* - * Copyright (C) 2006, Rusty Russell <rusty@rustcorp.com.au> IBM Corporation. - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, but - * WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or - * NON INFRINGEMENT. See the GNU General Public License for more - * details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. - */ -#include <linux/kernel.h> -#include <linux/start_kernel.h> -#include <linux/string.h> -#include <linux/console.h> -#include <linux/screen_info.h> -#include <linux/irq.h> -#include <linux/interrupt.h> -#include <linux/clocksource.h> -#include <linux/clockchips.h> -#include <linux/lguest.h> -#include <linux/lguest_launcher.h> -#include <linux/virtio_console.h> -#include <linux/pm.h> -#include <linux/export.h> -#include <linux/pci.h> -#include <linux/virtio_pci.h> -#include <asm/acpi.h> -#include <asm/apic.h> -#include <asm/lguest.h> -#include <asm/paravirt.h> -#include <asm/param.h> -#include <asm/page.h> -#include <asm/pgtable.h> -#include <asm/desc.h> -#include <asm/setup.h> -#include <asm/e820/api.h> -#include <asm/mce.h> -#include <asm/io.h> -#include <asm/fpu/api.h> -#include <asm/stackprotector.h> -#include <asm/reboot.h> /* for struct machine_ops */ -#include <asm/kvm_para.h> -#include <asm/pci_x86.h> -#include <asm/pci-direct.h> - -/*G:010 - * Welcome to the Guest! - * - * The Guest in our tale is a simple creature: identical to the Host but - * behaving in simplified but equivalent ways. In particular, the Guest is the - * same kernel as the Host (or at least, built from the same source code). -:*/ - -struct lguest_data lguest_data = { - .hcall_status = { [0 ... LHCALL_RING_SIZE-1] = 0xFF }, - .noirq_iret = (u32)lguest_noirq_iret, - .kernel_address = PAGE_OFFSET, - .blocked_interrupts = { 1 }, /* Block timer interrupts */ - .syscall_vec = IA32_SYSCALL_VECTOR, -}; - -/*G:037 - * async_hcall() is pretty simple: I'm quite proud of it really. We have a - * ring buffer of stored hypercalls which the Host will run though next time we - * do a normal hypercall. Each entry in the ring has 5 slots for the hypercall - * arguments, and a "hcall_status" word which is 0 if the call is ready to go, - * and 255 once the Host has finished with it. - * - * If we come around to a slot which hasn't been finished, then the table is - * full and we just make the hypercall directly. This has the nice side - * effect of causing the Host to run all the stored calls in the ring buffer - * which empties it for next time! - */ -static void async_hcall(unsigned long call, unsigned long arg1, - unsigned long arg2, unsigned long arg3, - unsigned long arg4) -{ - /* Note: This code assumes we're uniprocessor. */ - static unsigned int next_call; - unsigned long flags; - - /* - * Disable interrupts if not already disabled: we don't want an - * interrupt handler making a hypercall while we're already doing - * one! - */ - local_irq_save(flags); - if (lguest_data.hcall_status[next_call] != 0xFF) { - /* Table full, so do normal hcall which will flush table. */ - hcall(call, arg1, arg2, arg3, arg4); - } else { - lguest_data.hcalls[next_call].arg0 = call; - lguest_data.hcalls[next_call].arg1 = arg1; - lguest_data.hcalls[next_call].arg2 = arg2; - lguest_data.hcalls[next_call].arg3 = arg3; - lguest_data.hcalls[next_call].arg4 = arg4; - /* Arguments must all be written before we mark it to go */ - wmb(); - lguest_data.hcall_status[next_call] = 0; - if (++next_call == LHCALL_RING_SIZE) - next_call = 0; - } - local_irq_restore(flags); -} - -/*G:035 - * Notice the lazy_hcall() above, rather than hcall(). This is our first real - * optimization trick! - * - * When lazy_mode is set, it means we're allowed to defer all hypercalls and do - * them as a batch when lazy_mode is eventually turned off. Because hypercalls - * are reasonably expensive, batching them up makes sense. For example, a - * large munmap might update dozens of page table entries: that code calls - * paravirt_enter_lazy_mmu(), does the dozen updates, then calls - * lguest_leave_lazy_mode(). - * - * So, when we're in lazy mode, we call async_hcall() to store the call for - * future processing: - */ -static void lazy_hcall1(unsigned long call, unsigned long arg1) -{ - if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) - hcall(call, arg1, 0, 0, 0); - else - async_hcall(call, arg1, 0, 0, 0); -} - -/* You can imagine what lazy_hcall2, 3 and 4 look like. :*/ -static void lazy_hcall2(unsigned long call, - unsigned long arg1, - unsigned long arg2) -{ - if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) - hcall(call, arg1, arg2, 0, 0); - else - async_hcall(call, arg1, arg2, 0, 0); -} - -static void lazy_hcall3(unsigned long call, - unsigned long arg1, - unsigned long arg2, - unsigned long arg3) -{ - if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) - hcall(call, arg1, arg2, arg3, 0); - else - async_hcall(call, arg1, arg2, arg3, 0); -} - -#ifdef CONFIG_X86_PAE -static void lazy_hcall4(unsigned long call, - unsigned long arg1, - unsigned long arg2, - unsigned long arg3, - unsigned long arg4) -{ - if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) - hcall(call, arg1, arg2, arg3, arg4); - else - async_hcall(call, arg1, arg2, arg3, arg4); -} -#endif - -/*G:036 - * When lazy mode is turned off, we issue the do-nothing hypercall to - * flush any stored calls, and call the generic helper to reset the - * per-cpu lazy mode variable. - */ -static void lguest_leave_lazy_mmu_mode(void) -{ - hcall(LHCALL_FLUSH_ASYNC, 0, 0, 0, 0); - paravirt_leave_lazy_mmu(); -} - -/* - * We also catch the end of context switch; we enter lazy mode for much of - * that too, so again we need to flush here. - * - * (Technically, this is lazy CPU mode, and normally we're in lazy MMU - * mode, but unlike Xen, lguest doesn't care about the difference). - */ -static void lguest_end_context_switch(struct task_struct *next) -{ - hcall(LHCALL_FLUSH_ASYNC, 0, 0, 0, 0); - paravirt_end_context_switch(next); -} - -/*G:032 - * After that diversion we return to our first native-instruction - * replacements: four functions for interrupt control. - * - * The simplest way of implementing these would be to have "turn interrupts - * off" and "turn interrupts on" hypercalls. Unfortunately, this is too slow: - * these are by far the most commonly called functions of those we override. - * - * So instead we keep an "irq_enabled" field inside our "struct lguest_data", - * which the Guest can update with a single instruction. The Host knows to - * check there before it tries to deliver an interrupt. - */ - -/* - * save_flags() is expected to return the processor state (ie. "flags"). The - * flags word contains all kind of stuff, but in practice Linux only cares - * about the interrupt flag. Our "save_flags()" just returns that. - */ -asmlinkage __visible unsigned long lguest_save_fl(void) -{ - return lguest_data.irq_enabled; -} - -/* Interrupts go off... */ -asmlinkage __visible void lguest_irq_disable(void) -{ - lguest_data.irq_enabled = 0; -} - -/* - * Let's pause a moment. Remember how I said these are called so often? - * Jeremy Fitzhardinge optimized them so hard early in 2009 that he had to - * break some rules. In particular, these functions are assumed to save their - * own registers if they need to: normal C functions assume they can trash the - * eax register. To use normal C functions, we use - * PV_CALLEE_SAVE_REGS_THUNK(), which pushes %eax onto the stack, calls the - * C function, then restores it. - */ -PV_CALLEE_SAVE_REGS_THUNK(lguest_save_fl); -PV_CALLEE_SAVE_REGS_THUNK(lguest_irq_disable); -/*:*/ - -/* These are in head_32.S */ -extern void lg_irq_enable(void); -extern void lg_restore_fl(unsigned long flags); - -/*M:003 - * We could be more efficient in our checking of outstanding interrupts, rather - * than using a branch. One way would be to put the "irq_enabled" field in a - * page by itself, and have the Host write-protect it when an interrupt comes - * in when irqs are disabled. There will then be a page fault as soon as - * interrupts are re-enabled. - * - * A better method is to implement soft interrupt disable generally for x86: - * instead of disabling interrupts, we set a flag. If an interrupt does come - * in, we then disable them for real. This is uncommon, so we could simply use - * a hypercall for interrupt control and not worry about efficiency. -:*/ - -/*G:034 - * The Interrupt Descriptor Table (IDT). - * - * The IDT tells the processor what to do when an interrupt comes in. Each - * entry in the table is a 64-bit descriptor: this holds the privilege level, - * address of the handler, and... well, who cares? The Guest just asks the - * Host to make the change anyway, because the Host controls the real IDT. - */ -static void lguest_write_idt_entry(gate_desc *dt, - int entrynum, const gate_desc *g) -{ - /* - * The gate_desc structure is 8 bytes long: we hand it to the Host in - * two 32-bit chunks. The whole 32-bit kernel used to hand descriptors - * around like this; typesafety wasn't a big concern in Linux's early - * years. - */ - u32 *desc = (u32 *)g; - /* Keep the local copy up to date. */ - native_write_idt_entry(dt, entrynum, g); - /* Tell Host about this new entry. */ - hcall(LHCALL_LOAD_IDT_ENTRY, entrynum, desc[0], desc[1], 0); -} - -/* - * Changing to a different IDT is very rare: we keep the IDT up-to-date every - * time it is written, so we can simply loop through all entries and tell the - * Host about them. - */ -static void lguest_load_idt(const struct desc_ptr *desc) -{ - unsigned int i; - struct desc_struct *idt = (void *)desc->address; - - for (i = 0; i < (desc->size+1)/8; i++) - hcall(LHCALL_LOAD_IDT_ENTRY, i, idt[i].a, idt[i].b, 0); -} - -/* - * The Global Descriptor Table. - * - * The Intel architecture defines another table, called the Global Descriptor - * Table (GDT). You tell the CPU where it is (and its size) using the "lgdt" - * instruction, and then several other instructions refer to entries in the - * table. There are three entries which the Switcher needs, so the Host simply - * controls the entire thing and the Guest asks it to make changes using the - * LOAD_GDT hypercall. - * - * This is the exactly like the IDT code. - */ -static void lguest_load_gdt(const struct desc_ptr *desc) -{ - unsigned int i; - struct desc_struct *gdt = (void *)desc->address; - - for (i = 0; i < (desc->size+1)/8; i++) - hcall(LHCALL_LOAD_GDT_ENTRY, i, gdt[i].a, gdt[i].b, 0); -} - -/* - * For a single GDT entry which changes, we simply change our copy and - * then tell the host about it. - */ -static void lguest_write_gdt_entry(struct desc_struct *dt, int entrynum, - const void *desc, int type) -{ - native_write_gdt_entry(dt, entrynum, desc, type); - /* Tell Host about this new entry. */ - hcall(LHCALL_LOAD_GDT_ENTRY, entrynum, - dt[entrynum].a, dt[entrynum].b, 0); -} - -/* - * There are three "thread local storage" GDT entries which change - * on every context switch (these three entries are how glibc implements - * __thread variables). As an optimization, we have a hypercall - * specifically for this case. - * - * Wouldn't it be nicer to have a general LOAD_GDT_ENTRIES hypercall - * which took a range of entries? - */ -static void lguest_load_tls(struct thread_struct *t, unsigned int cpu) -{ - /* - * There's one problem which normal hardware doesn't have: the Host - * can't handle us removing entries we're currently using. So we clear - * the GS register here: if it's needed it'll be reloaded anyway. - */ - lazy_load_gs(0); - lazy_hcall2(LHCALL_LOAD_TLS, __pa(&t->tls_array), cpu); -} - -/*G:038 - * That's enough excitement for now, back to ploughing through each of the - * different pv_ops structures (we're about 1/3 of the way through). - * - * This is the Local Descriptor Table, another weird Intel thingy. Linux only - * uses this for some strange applications like Wine. We don't do anything - * here, so they'll get an informative and friendly Segmentation Fault. - */ -static void lguest_set_ldt(const void *addr, unsigned entries) -{ -} - -/* - * This loads a GDT entry into the "Task Register": that entry points to a - * structure called the Task State Segment. Some comments scattered though the - * kernel code indicate that this used for task switching in ages past, along - * with blood sacrifice and astrology. - * - * Now there's nothing interesting in here that we don't get told elsewhere. - * But the native version uses the "ltr" instruction, which makes the Host - * complain to the Guest about a Segmentation Fault and it'll oops. So we - * override the native version with a do-nothing version. - */ -static void lguest_load_tr_desc(void) -{ -} - -/* - * The "cpuid" instruction is a way of querying both the CPU identity - * (manufacturer, model, etc) and its features. It was introduced before the - * Pentium in 1993 and keeps getting extended by both Intel, AMD and others. - * As you might imagine, after a decade and a half this treatment, it is now a - * giant ball of hair. Its entry in the current Intel manual runs to 28 pages. - * - * This instruction even it has its own Wikipedia entry. The Wikipedia entry - * has been translated into 6 languages. I am not making this up! - * - * We could get funky here and identify ourselves as "GenuineLguest", but - * instead we just use the real "cpuid" instruction. Then I pretty much turned - * off feature bits until the Guest booted. (Don't say that: you'll damage - * lguest sales!) Shut up, inner voice! (Hey, just pointing out that this is - * hardly future proof.) No one's listening! They don't like you anyway, - * parenthetic weirdo! - * - * Replacing the cpuid so we can turn features off is great for the kernel, but - * anyone (including userspace) can just use the raw "cpuid" instruction and - * the Host won't even notice since it isn't privileged. So we try not to get - * too worked up about it. - */ -static void lguest_cpuid(unsigned int *ax, unsigned int *bx, - unsigned int *cx, unsigned int *dx) -{ - int function = *ax; - - native_cpuid(ax, bx, cx, dx); - switch (function) { - /* - * CPUID 0 gives the highest legal CPUID number (and the ID string). - * We futureproof our code a little by sticking to known CPUID values. - */ - case 0: - if (*ax > 5) - *ax = 5; - break; - - /* - * CPUID 1 is a basic feature request. - * - * CX: we only allow kernel to see SSE3, CMPXCHG16B and SSSE3 - * DX: SSE, SSE2, FXSR, MMX, CMOV, CMPXCHG8B, TSC, FPU and PAE. - */ - case 1: - *cx &= 0x00002201; - *dx &= 0x07808151; - /* - * The Host can do a nice optimization if it knows that the - * kernel mappings (addresses above 0xC0000000 or whatever - * PAGE_OFFSET is set to) haven't changed. But Linux calls - * flush_tlb_user() for both user and kernel mappings unless - * the Page Global Enable (PGE) feature bit is set. - */ - *dx |= 0x00002000; - /* - * We also lie, and say we're family id 5. 6 or greater - * leads to a rdmsr in early_init_intel which we can't handle. - * Family ID is returned as bits 8-12 in ax. - */ - *ax &= 0xFFFFF0FF; - *ax |= 0x00000500; - break; - - /* - * This is used to detect if we're running under KVM. We might be, - * but that's a Host matter, not us. So say we're not. - */ - case KVM_CPUID_SIGNATURE: - *bx = *cx = *dx = 0; - break; - - /* - * 0x80000000 returns the highest Extended Function, so we futureproof - * like we do above by limiting it to known fields. - */ - case 0x80000000: - if (*ax > 0x80000008) - *ax = 0x80000008; - break; - - /* - * PAE systems can mark pages as non-executable. Linux calls this the - * NX bit. Intel calls it XD (eXecute Disable), AMD EVP (Enhanced - * Virus Protection). We just switch it off here, since we don't - * support it. - */ - case 0x80000001: - *dx &= ~(1 << 20); - break; - } -} - -/* - * Intel has four control registers, imaginatively named cr0, cr2, cr3 and cr4. - * I assume there's a cr1, but it hasn't bothered us yet, so we'll not bother - * it. The Host needs to know when the Guest wants to change them, so we have - * a whole series of functions like read_cr0() and write_cr0(). - * - * We start with cr0. cr0 allows you to turn on and off all kinds of basic - * features, but the only cr0 bit that Linux ever used at runtime was the - * horrifically-named Task Switched (TS) bit at bit 3 (ie. 8) - * - * What does the TS bit do? Well, it causes the CPU to trap (interrupt 7) if - * the floating point unit is used. Which allows us to restore FPU state - * lazily after a task switch if we wanted to, but wouldn't a name like - * "FPUTRAP bit" be a little less cryptic? - * - * Fortunately, Linux keeps it simple and doesn't use TS, so we can ignore - * cr0. - */ -static void lguest_write_cr0(unsigned long val) -{ -} - -static unsigned long lguest_read_cr0(void) -{ - return 0; -} - -/* - * cr2 is the virtual address of the last page fault, which the Guest only ever - * reads. The Host kindly writes this into our "struct lguest_data", so we - * just read it out of there. - */ -static unsigned long lguest_read_cr2(void) -{ - return lguest_data.cr2; -} - -/* See lguest_set_pte() below. */ -static bool cr3_changed = false; -static unsigned long current_cr3; - -/* - * cr3 is the current toplevel pagetable page: the principle is the same as - * cr0. Keep a local copy, and tell the Host when it changes. - */ -static void lguest_write_cr3(unsigned long cr3) -{ - lazy_hcall1(LHCALL_NEW_PGTABLE, cr3); - current_cr3 = cr3; - - /* These two page tables are simple, linear, and used during boot */ - if (cr3 != __pa_symbol(swapper_pg_dir) && - cr3 != __pa_symbol(initial_page_table)) - cr3_changed = true; -} - -static unsigned long lguest_read_cr3(void) -{ - return current_cr3; -} - -/* cr4 is used to enable and disable PGE, but we don't care. */ -static unsigned long lguest_read_cr4(void) -{ - return 0; -} - -static void lguest_write_cr4(unsigned long val) -{ -} - -/* - * Page Table Handling. - * - * Now would be a good time to take a rest and grab a coffee or similarly - * relaxing stimulant. The easy parts are behind us, and the trek gradually - * winds uphill from here. - * - * Quick refresher: memory is divided into "pages" of 4096 bytes each. The CPU - * maps virtual addresses to physical addresses using "page tables". We could - * use one huge index of 1 million entries: each address is 4 bytes, so that's - * 1024 pages just to hold the page tables. But since most virtual addresses - * are unused, we use a two level index which saves space. The cr3 register - * contains the physical address of the top level "page directory" page, which - * contains physical addresses of up to 1024 second-level pages. Each of these - * second level pages contains up to 1024 physical addresses of actual pages, - * or Page Table Entries (PTEs). - * - * Here's a diagram, where arrows indicate physical addresses: - * - * cr3 ---> +---------+ - * | --------->+---------+ - * | | | PADDR1 | - * Mid-level | | PADDR2 | - * (PMD) page | | | - * | | Lower-level | - * | | (PTE) page | - * | | | | - * .... .... - * - * So to convert a virtual address to a physical address, we look up the top - * level, which points us to the second level, which gives us the physical - * address of that page. If the top level entry was not present, or the second - * level entry was not present, then the virtual address is invalid (we - * say "the page was not mapped"). - * - * Put another way, a 32-bit virtual address is divided up like so: - * - * 1 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 - * |<---- 10 bits ---->|<---- 10 bits ---->|<------ 12 bits ------>| - * Index into top Index into second Offset within page - * page directory page pagetable page - * - * Now, unfortunately, this isn't the whole story: Intel added Physical Address - * Extension (PAE) to allow 32 bit systems to use 64GB of memory (ie. 36 bits). - * These are held in 64-bit page table entries, so we can now only fit 512 - * entries in a page, and the neat three-level tree breaks down. - * - * The result is a four level page table: - * - * cr3 --> [ 4 Upper ] - * [ Level ] - * [ Entries ] - * [(PUD Page)]---> +---------+ - * | --------->+---------+ - * | | | PADDR1 | - * Mid-level | | PADDR2 | - * (PMD) page | | | - * | | Lower-level | - * | | (PTE) page | - * | | | | - * .... .... - * - * - * And the virtual address is decoded as: - * - * 1 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 - * |<-2->|<--- 9 bits ---->|<---- 9 bits --->|<------ 12 bits ------>| - * Index into Index into mid Index into lower Offset within page - * top entries directory page pagetable page - * - * It's too hard to switch between these two formats at runtime, so Linux only - * supports one or the other depending on whether CONFIG_X86_PAE is set. Many - * distributions turn it on, and not just for people with silly amounts of - * memory: the larger PTE entries allow room for the NX bit, which lets the - * kernel disable execution of pages and increase security. - * - * This was a problem for lguest, which couldn't run on these distributions; - * then Matias Zabaljauregui figured it all out and implemented it, and only a - * handful of puppies were crushed in the process! - * - * Back to our point: the kernel spends a lot of time changing both the - * top-level page directory and lower-level pagetable pages. The Guest doesn't - * know physical addresses, so while it maintains these page tables exactly - * like normal, it also needs to keep the Host informed whenever it makes a - * change: the Host will create the real page tables based on the Guests'. - */ - -/* - * The Guest calls this after it has set a second-level entry (pte), ie. to map - * a page into a process' address space. We tell the Host the toplevel and - * address this corresponds to. The Guest uses one pagetable per process, so - * we need to tell the Host which one we're changing (mm->pgd). - */ -static void lguest_pte_update(struct mm_struct *mm, unsigned long addr, - pte_t *ptep) -{ -#ifdef CONFIG_X86_PAE - /* PAE needs to hand a 64 bit page table entry, so it uses two args. */ - lazy_hcall4(LHCALL_SET_PTE, __pa(mm->pgd), addr, - ptep->pte_low, ptep->pte_high); -#else - lazy_hcall3(LHCALL_SET_PTE, __pa(mm->pgd), addr, ptep->pte_low); -#endif -} - -/* This is the "set and update" combo-meal-deal version. */ -static void lguest_set_pte_at(struct mm_struct *mm, unsigned long addr, - pte_t *ptep, pte_t pteval) -{ - native_set_pte(ptep, pteval); - lguest_pte_update(mm, addr, ptep); -} - -/* - * The Guest calls lguest_set_pud to set a top-level entry and lguest_set_pmd - * to set a middle-level entry when PAE is activated. - * - * Again, we set the entry then tell the Host which page we changed, - * and the index of the entry we changed. - */ -#ifdef CONFIG_X86_PAE -static void lguest_set_pud(pud_t *pudp, pud_t pudval) -{ - native_set_pud(pudp, pudval); - - /* 32 bytes aligned pdpt address and the index. */ - lazy_hcall2(LHCALL_SET_PGD, __pa(pudp) & 0xFFFFFFE0, - (__pa(pudp) & 0x1F) / sizeof(pud_t)); -} - -static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval) -{ - native_set_pmd(pmdp, pmdval); - lazy_hcall2(LHCALL_SET_PMD, __pa(pmdp) & PAGE_MASK, - (__pa(pmdp) & (PAGE_SIZE - 1)) / sizeof(pmd_t)); -} -#else - -/* The Guest calls lguest_set_pmd to set a top-level entry when !PAE. */ -static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval) -{ - native_set_pmd(pmdp, pmdval); - lazy_hcall2(LHCALL_SET_PGD, __pa(pmdp) & PAGE_MASK, - (__pa(pmdp) & (PAGE_SIZE - 1)) / sizeof(pmd_t)); -} -#endif - -/* - * There are a couple of legacy places where the kernel sets a PTE, but we - * don't know the top level any more. This is useless for us, since we don't - * know which pagetable is changing or what address, so we just tell the Host - * to forget all of them. Fortunately, this is very rare. - * - * ... except in early boot when the kernel sets up the initial pagetables, - * which makes booting astonishingly slow: 48 seconds! So we don't even tell - * the Host anything changed until we've done the first real page table switch, - * which brings boot back to 4.3 seconds. - */ -static void lguest_set_pte(pte_t *ptep, pte_t pteval) -{ - native_set_pte(ptep, pteval); - if (cr3_changed) - lazy_hcall1(LHCALL_FLUSH_TLB, 1); -} - -#ifdef CONFIG_X86_PAE -/* - * With 64-bit PTE values, we need to be careful setting them: if we set 32 - * bits at a time, the hardware could see a weird half-set entry. These - * versions ensure we update all 64 bits at once. - */ -static void lguest_set_pte_atomic(pte_t *ptep, pte_t pte) -{ - native_set_pte_atomic(ptep, pte); - if (cr3_changed) - lazy_hcall1(LHCALL_FLUSH_TLB, 1); -} - -static void lguest_pte_clear(struct mm_struct *mm, unsigned long addr, - pte_t *ptep) -{ - native_pte_clear(mm, addr, ptep); - lguest_pte_update(mm, addr, ptep); -} - -static void lguest_pmd_clear(pmd_t *pmdp) -{ - lguest_set_pmd(pmdp, __pmd(0)); -} -#endif - -/* - * Unfortunately for Lguest, the pv_mmu_ops for page tables were based on - * native page table operations. On native hardware you can set a new page - * table entry whenever you want, but if you want to remove one you have to do - * a TLB flush (a TLB is a little cache of page table entries kept by the CPU). - * - * So the lguest_set_pte_at() and lguest_set_pmd() functions above are only - * called when a valid entry is written, not when it's removed (ie. marked not - * present). Instead, this is where we come when the Guest wants to remove a - * page table entry: we tell the Host to set that entry to 0 (ie. the present - * bit is zero). - */ -static void lguest_flush_tlb_single(unsigned long addr) -{ - /* Simply set it to zero: if it was not, it will fault back in. */ - lazy_hcall3(LHCALL_SET_PTE, current_cr3, addr, 0); -} - -/* - * This is what happens after the Guest has removed a large number of entries. - * This tells the Host that any of the page table entries for userspace might - * have changed, ie. virtual addresses below PAGE_OFFSET. - */ -static void lguest_flush_tlb_user(void) -{ - lazy_hcall1(LHCALL_FLUSH_TLB, 0); -} - -/* - * This is called when the kernel page tables have changed. That's not very - * common (unless the Guest is using highmem, which makes the Guest extremely - * slow), so it's worth separating this from the user flushing above. - */ -static void lguest_flush_tlb_kernel(void) -{ - lazy_hcall1(LHCALL_FLUSH_TLB, 1); -} - -/* - * The Unadvanced Programmable Interrupt Controller. - * - * This is an attempt to implement the simplest possible interrupt controller. - * I spent some time looking though routines like set_irq_chip_and_handler, - * set_irq_chip_and_handler_name, set_irq_chip_data and set_phasers_to_stun and - * I *think* this is as simple as it gets. - * - * We can tell the Host what interrupts we want blocked ready for using the - * lguest_data.interrupts bitmap, so disabling (aka "masking") them is as - * simple as setting a bit. We don't actually "ack" interrupts as such, we - * just mask and unmask them. I wonder if we should be cleverer? - */ -static void disable_lguest_irq(struct irq_data *data) -{ - set_bit(data->irq, lguest_data.blocked_interrupts); -} - -static void enable_lguest_irq(struct irq_data *data) -{ - clear_bit(data->irq, lguest_data.blocked_interrupts); -} - -/* This structure describes the lguest IRQ controller. */ -static struct irq_chip lguest_irq_controller = { - .name = "lguest", - .irq_mask = disable_lguest_irq, - .irq_mask_ack = disable_lguest_irq, - .irq_unmask = enable_lguest_irq, -}; - -/* - * Interrupt descriptors are allocated as-needed, but low-numbered ones are - * reserved by the generic x86 code. So we ignore irq_alloc_desc_at if it - * tells us the irq is already used: other errors (ie. ENOMEM) we take - * seriously. - */ -static int lguest_setup_irq(unsigned int irq) -{ - struct irq_desc *desc; - int err; - - /* Returns -ve error or vector number. */ - err = irq_alloc_desc_at(irq, 0); - if (err < 0 && err != -EEXIST) - return err; - - /* - * Tell the Linux infrastructure that the interrupt is - * controlled by our level-based lguest interrupt controller. - */ - irq_set_chip_and_handler_name(irq, &lguest_irq_controller, - handle_level_irq, "level"); - - /* Some systems map "vectors" to interrupts weirdly. Not us! */ - desc = irq_to_desc(irq); - __this_cpu_write(vector_irq[FIRST_EXTERNAL_VECTOR + irq], desc); - return 0; -} - -static int lguest_enable_irq(struct pci_dev *dev) -{ - int err; - u8 line = 0; - - /* We literally use the PCI interrupt line as the irq number. */ - pci_read_config_byte(dev, PCI_INTERRUPT_LINE, &line); - err = lguest_setup_irq(line); - if (!err) - dev->irq = line; - return err; -} - -/* We don't do hotplug PCI, so this shouldn't be called. */ -static void lguest_disable_irq(struct pci_dev *dev) -{ - WARN_ON(1); -} - -/* - * This sets up the Interrupt Descriptor Table (IDT) entry for each hardware - * interrupt (except 128, which is used for system calls). - */ -static void __init lguest_init_IRQ(void) -{ - unsigned int i; - - for (i = FIRST_EXTERNAL_VECTOR; i < FIRST_SYSTEM_VECTOR; i++) { - if (i != IA32_SYSCALL_VECTOR) - set_intr_gate(i, irq_entries_start + - 8 * (i - FIRST_EXTERNAL_VECTOR)); - } - - /* - * This call is required to set up for 4k stacks, where we have - * separate stacks for hard and soft interrupts. - */ - irq_ctx_init(smp_processor_id()); -} - -/* - * Time. - * - * It would be far better for everyone if the Guest had its own clock, but - * until then the Host gives us the time on every interrupt. - */ -static void lguest_get_wallclock(struct timespec *now) -{ - *now = lguest_data.time; -} - -/* - * The TSC is an Intel thing called the Time Stamp Counter. The Host tells us - * what speed it runs at, or 0 if it's unusable as a reliable clock source. - * This matches what we want here: if we return 0 from this function, the x86 - * TSC clock will give up and not register itself. - */ -static unsigned long lguest_tsc_khz(void) -{ - return lguest_data.tsc_khz; -} - -/* - * If we can't use the TSC, the kernel falls back to our lower-priority - * "lguest_clock", where we read the time value given to us by the Host. - */ -static u64 lguest_clock_read(struct clocksource *cs) -{ - unsigned long sec, nsec; - - /* - * Since the time is in two parts (seconds and nanoseconds), we risk - * reading it just as it's changing from 99 & 0.999999999 to 100 and 0, - * and getting 99 and 0. As Linux tends to come apart under the stress - * of time travel, we must be careful: - */ - do { - /* First we read the seconds part. */ - sec = lguest_data.time.tv_sec; - /* - * This read memory barrier tells the compiler and the CPU that - * this can't be reordered: we have to complete the above - * before going on. - */ - rmb(); - /* Now we read the nanoseconds part. */ - nsec = lguest_data.time.tv_nsec; - /* Make sure we've done that. */ - rmb(); - /* Now if the seconds part has changed, try again. */ - } while (unlikely(lguest_data.time.tv_sec != sec)); - - /* Our lguest clock is in real nanoseconds. */ - return sec*1000000000ULL + nsec; -} - -/* This is the fallback clocksource: lower priority than the TSC clocksource. */ -static struct clocksource lguest_clock = { - .name = "lguest", - .rating = 200, - .read = lguest_clock_read, - .mask = CLOCKSOURCE_MASK(64), - .flags = CLOCK_SOURCE_IS_CONTINUOUS, -}; - -/* - * We also need a "struct clock_event_device": Linux asks us to set it to go - * off some time in the future. Actually, James Morris figured all this out, I - * just applied the patch. - */ -static int lguest_clockevent_set_next_event(unsigned long delta, - struct clock_event_device *evt) -{ - /* FIXME: I don't think this can ever happen, but James tells me he had - * to put this code in. Maybe we should remove it now. Anyone? */ - if (delta < LG_CLOCK_MIN_DELTA) { - if (printk_ratelimit()) - printk(KERN_DEBUG "%s: small delta %lu ns\n", - __func__, delta); - return -ETIME; - } - - /* Please wake us this far in the future. */ - hcall(LHCALL_SET_CLOCKEVENT, delta, 0, 0, 0); - return 0; -} - -static int lguest_clockevent_shutdown(struct clock_event_device *evt) -{ - /* A 0 argument shuts the clock down. */ - hcall(LHCALL_SET_CLOCKEVENT, 0, 0, 0, 0); - return 0; -} - -/* This describes our primitive timer chip. */ -static struct clock_event_device lguest_clockevent = { - .name = "lguest", - .features = CLOCK_EVT_FEAT_ONESHOT, - .set_next_event = lguest_clockevent_set_next_event, - .set_state_shutdown = lguest_clockevent_shutdown, - .rating = INT_MAX, - .mult = 1, - .shift = 0, - .min_delta_ns = LG_CLOCK_MIN_DELTA, - .min_delta_ticks = LG_CLOCK_MIN_DELTA, - .max_delta_ns = LG_CLOCK_MAX_DELTA, - .max_delta_ticks = LG_CLOCK_MAX_DELTA, -}; - -/* - * This is the Guest timer interrupt handler (hardware interrupt 0). We just - * call the clockevent infrastructure and it does whatever needs doing. - */ -static void lguest_time_irq(struct irq_desc *desc) -{ - unsigned long flags; - - /* Don't interrupt us while this is running. */ - local_irq_save(flags); - lguest_clockevent.event_handler(&lguest_clockevent); - local_irq_restore(flags); -} - -/* - * At some point in the boot process, we get asked to set up our timing - * infrastructure. The kernel doesn't expect timer interrupts before this, but - * we cleverly initialized the "blocked_interrupts" field of "struct - * lguest_data" so that timer interrupts were blocked until now. - */ -static void lguest_time_init(void) -{ - /* Set up the timer interrupt (0) to go to our simple timer routine */ - if (lguest_setup_irq(0) != 0) - panic("Could not set up timer irq"); - irq_set_handler(0, lguest_time_irq); - - clocksource_register_hz(&lguest_clock, NSEC_PER_SEC); - - /* We can't set cpumask in the initializer: damn C limitations! Set it - * here and register our timer device. */ - lguest_clockevent.cpumask = cpumask_of(0); - clockevents_register_device(&lguest_clockevent); - - /* Finally, we unblock the timer interrupt. */ - clear_bit(0, lguest_data.blocked_interrupts); -} - -/* - * Miscellaneous bits and pieces. - * - * Here is an oddball collection of functions which the Guest needs for things - * to work. They're pretty simple. - */ - -/* - * The Guest needs to tell the Host what stack it expects traps to use. For - * native hardware, this is part of the Task State Segment mentioned above in - * lguest_load_tr_desc(), but to help hypervisors there's this special call. - * - * We tell the Host the segment we want to use (__KERNEL_DS is the kernel data - * segment), the privilege level (we're privilege level 1, the Host is 0 and - * will not tolerate us trying to use that), the stack pointer, and the number - * of pages in the stack. - */ -static void lguest_load_sp0(struct tss_struct *tss, - struct thread_struct *thread) -{ - lazy_hcall3(LHCALL_SET_STACK, __KERNEL_DS | 0x1, thread->sp0, - THREAD_SIZE / PAGE_SIZE); - tss->x86_tss.sp0 = thread->sp0; -} - -/* Let's just say, I wouldn't do debugging under a Guest. */ -static unsigned long lguest_get_debugreg(int regno) -{ - /* FIXME: Implement */ - return 0; -} - -static void lguest_set_debugreg(int regno, unsigned long value) -{ - /* FIXME: Implement */ -} - -/* - * There are times when the kernel wants to make sure that no memory writes are - * caught in the cache (that they've all reached real hardware devices). This - * doesn't matter for the Guest which has virtual hardware. - * - * On the Pentium 4 and above, cpuid() indicates that the Cache Line Flush - * (clflush) instruction is available and the kernel uses that. Otherwise, it - * uses the older "Write Back and Invalidate Cache" (wbinvd) instruction. - * Unlike clflush, wbinvd can only be run at privilege level 0. So we can - * ignore clflush, but replace wbinvd. - */ -static void lguest_wbinvd(void) -{ -} - -/* - * If the Guest expects to have an Advanced Programmable Interrupt Controller, - * we play dumb by ignoring writes and returning 0 for reads. So it's no - * longer Programmable nor Controlling anything, and I don't think 8 lines of - * code qualifies for Advanced. It will also never interrupt anything. It - * does, however, allow us to get through the Linux boot code. - */ -#ifdef CONFIG_X86_LOCAL_APIC -static void lguest_apic_write(u32 reg, u32 v) -{ -} - -static u32 lguest_apic_read(u32 reg) -{ - return 0; -} - -static u64 lguest_apic_icr_read(void) -{ - return 0; -} - -static void lguest_apic_icr_write(u32 low, u32 id) -{ - /* Warn to see if there's any stray references */ - WARN_ON(1); -} - -static void lguest_apic_wait_icr_idle(void) -{ - return; -} - -static u32 lguest_apic_safe_wait_icr_idle(void) -{ - return 0; -} - -static void set_lguest_basic_apic_ops(void) -{ - apic->read = lguest_apic_read; - apic->write = lguest_apic_write; - apic->icr_read = lguest_apic_icr_read; - apic->icr_write = lguest_apic_icr_write; - apic->wait_icr_idle = lguest_apic_wait_icr_idle; - apic->safe_wait_icr_idle = lguest_apic_safe_wait_icr_idle; -}; -#endif - -/* STOP! Until an interrupt comes in. */ -static void lguest_safe_halt(void) -{ - hcall(LHCALL_HALT, 0, 0, 0, 0); -} - -/* - * The SHUTDOWN hypercall takes a string to describe what's happening, and - * an argument which says whether this to restart (reboot) the Guest or not. - * - * Note that the Host always prefers that the Guest speak in physical addresses - * rather than virtual addresses, so we use __pa() here. - */ -static void lguest_power_off(void) -{ - hcall(LHCALL_SHUTDOWN, __pa("Power down"), - LGUEST_SHUTDOWN_POWEROFF, 0, 0); -} - -/* - * Panicing. - * - * Don't. But if you did, this is what happens. - */ -static int lguest_panic(struct notifier_block *nb, unsigned long l, void *p) -{ - hcall(LHCALL_SHUTDOWN, __pa(p), LGUEST_SHUTDOWN_POWEROFF, 0, 0); - /* The hcall won't return, but to keep gcc happy, we're "done". */ - return NOTIFY_DONE; -} - -static struct notifier_block paniced = { - .notifier_call = lguest_panic -}; - -/* Setting up memory is fairly easy. */ -static __init char *lguest_memory_setup(void) -{ - /* - * The Linux bootloader header contains an "e820" memory map: the - * Launcher populated the first entry with our memory limit. - */ - e820__range_add(boot_params.e820_table[0].addr, - boot_params.e820_table[0].size, - boot_params.e820_table[0].type); - - /* This string is for the boot messages. */ - return "LGUEST"; -} - -/* Offset within PCI config space of BAR access capability. */ -static int console_cfg_offset = 0; -static int console_access_cap; - -/* Set up so that we access off in bar0 (on bus 0, device 1, function 0) */ -static void set_cfg_window(u32 cfg_offset, u32 off) -{ - write_pci_config_byte(0, 1, 0, - cfg_offset + offsetof(struct virtio_pci_cap, bar), - 0); - write_pci_config(0, 1, 0, - cfg_offset + offsetof(struct virtio_pci_cap, length), - 4); - write_pci_config(0, 1, 0, - cfg_offset + offsetof(struct virtio_pci_cap, offset), - off); -} - -static void write_bar_via_cfg(u32 cfg_offset, u32 off, u32 val) -{ - /* - * We could set this up once, then leave it; nothing else in the * - * kernel should touch these registers. But if it went wrong, that - * would be a horrible bug to find. - */ - set_cfg_window(cfg_offset, off); - write_pci_config(0, 1, 0, - cfg_offset + sizeof(struct virtio_pci_cap), val); -} - -static void probe_pci_console(void) -{ - u8 cap, common_cap = 0, device_cap = 0; - u32 device_len; - - /* Avoid recursive printk into here. */ - console_cfg_offset = -1; - - if (!early_pci_allowed()) { - printk(KERN_ERR "lguest: early PCI access not allowed!\n"); - return; - } - - /* We expect a console PCI device at BUS0, slot 1. */ - if (read_pci_config(0, 1, 0, 0) != 0x10431AF4) { - printk(KERN_ERR "lguest: PCI device is %#x!\n", - read_pci_config(0, 1, 0, 0)); - return; - } - - /* Find the capabilities we need (must be in bar0) */ - cap = read_pci_config_byte(0, 1, 0, PCI_CAPABILITY_LIST); - while (cap) { - u8 vndr = read_pci_config_byte(0, 1, 0, cap); - if (vndr == PCI_CAP_ID_VNDR) { - u8 type, bar; - - type = read_pci_config_byte(0, 1, 0, - cap + offsetof(struct virtio_pci_cap, cfg_type)); - bar = read_pci_config_byte(0, 1, 0, - cap + offsetof(struct virtio_pci_cap, bar)); - - switch (type) { - case VIRTIO_PCI_CAP_DEVICE_CFG: - if (bar == 0) - device_cap = cap; - break; - case VIRTIO_PCI_CAP_PCI_CFG: - console_access_cap = cap; - break; - } - } - cap = read_pci_config_byte(0, 1, 0, cap + PCI_CAP_LIST_NEXT); - } - if (!device_cap || !console_access_cap) { - printk(KERN_ERR "lguest: No caps (%u/%u/%u) in console!\n", - common_cap, device_cap, console_access_cap); - return; - } - - /* - * Note that we can't check features, until we've set the DRIVER - * status bit. We don't want to do that until we have a real driver, - * so we just check that the device-specific config has room for - * emerg_wr. If it doesn't support VIRTIO_CONSOLE_F_EMERG_WRITE - * it should ignore the access. - */ - device_len = read_pci_config(0, 1, 0, - device_cap + offsetof(struct virtio_pci_cap, length)); - if (device_len < (offsetof(struct virtio_console_config, emerg_wr) - + sizeof(u32))) { - printk(KERN_ERR "lguest: console missing emerg_wr field\n"); - return; - } - - console_cfg_offset = read_pci_config(0, 1, 0, - device_cap + offsetof(struct virtio_pci_cap, offset)); - printk(KERN_INFO "lguest: Console via virtio-pci emerg_wr\n"); -} - -/* - * We will eventually use the virtio console device to produce console output, - * but before that is set up we use the virtio PCI console's backdoor mmio - * access and the "emergency" write facility (which is legal even before the - * device is configured). - */ -static __init int early_put_chars(u32 vtermno, const char *buf, int count) -{ - /* If we couldn't find PCI console, forget it. */ - if (console_cfg_offset < 0) - return count; - - if (unlikely(!console_cfg_offset)) { - probe_pci_console(); - if (console_cfg_offset < 0) - return count; - } - - write_bar_via_cfg(console_access_cap, - console_cfg_offset - + offsetof(struct virtio_console_config, emerg_wr), - buf[0]); - return 1; -} - -/* - * Rebooting also tells the Host we're finished, but the RESTART flag tells the - * Launcher to reboot us. - */ -static void lguest_restart(char *reason) -{ - hcall(LHCALL_SHUTDOWN, __pa(reason), LGUEST_SHUTDOWN_RESTART, 0, 0); -} - -/*G:050 - * Patching (Powerfully Placating Performance Pedants) - * - * We have already seen that pv_ops structures let us replace simple native - * instructions with calls to the appropriate back end all throughout the - * kernel. This allows the same kernel to run as a Guest and as a native - * kernel, but it's slow because of all the indirect branches. - * - * Remember that David Wheeler quote about "Any problem in computer science can - * be solved with another layer of indirection"? The rest of that quote is - * "... But that usually will create another problem." This is the first of - * those problems. - * - * Our current solution is to allow the paravirt back end to optionally patch - * over the indirect calls to replace them with something more efficient. We - * patch two of the simplest of the most commonly called functions: disable - * interrupts and save interrupts. We usually have 6 or 10 bytes to patch - * into: the Guest versions of these operations are small enough that we can - * fit comfortably. - * - * First we need assembly templates of each of the patchable Guest operations, - * and these are in head_32.S. - */ - -/*G:060 We construct a table from the assembler templates: */ -static const struct lguest_insns -{ - const char *start, *end; -} lguest_insns[] = { - [PARAVIRT_PATCH(pv_irq_ops.irq_disable)] = { lgstart_cli, lgend_cli }, - [PARAVIRT_PATCH(pv_irq_ops.save_fl)] = { lgstart_pushf, lgend_pushf }, -}; - -/* - * Now our patch routine is fairly simple (based on the native one in - * paravirt.c). If we have a replacement, we copy it in and return how much of - * the available space we used. - */ -static unsigned lguest_patch(u8 type, u16 clobber, void *ibuf, - unsigned long addr, unsigned len) -{ - unsigned int insn_len; - - /* Don't do anything special if we don't have a replacement */ - if (type >= ARRAY_SIZE(lguest_insns) || !lguest_insns[type].start) - return paravirt_patch_default(type, clobber, ibuf, addr, len); - - insn_len = lguest_insns[type].end - lguest_insns[type].start; - - /* Similarly if it can't fit (doesn't happen, but let's be thorough). */ - if (len < insn_len) - return paravirt_patch_default(type, clobber, ibuf, addr, len); - - /* Copy in our instructions. */ - memcpy(ibuf, lguest_insns[type].start, insn_len); - return insn_len; -} - -/*G:029 - * Once we get to lguest_init(), we know we're a Guest. The various - * pv_ops structures in the kernel provide points for (almost) every routine we - * have to override to avoid privileged instructions. - */ -__init void lguest_init(void) -{ - /* We're under lguest. */ - pv_info.name = "lguest"; - /* We're running at privilege level 1, not 0 as normal. */ - pv_info.kernel_rpl = 1; - /* Everyone except Xen runs with this set. */ - pv_info.shared_kernel_pmd = 1; - - /* - * We set up all the lguest overrides for sensitive operations. These - * are detailed with the operations themselves. - */ - - /* Interrupt-related operations */ - pv_irq_ops.save_fl = PV_CALLEE_SAVE(lguest_save_fl); - pv_irq_ops.restore_fl = __PV_IS_CALLEE_SAVE(lg_restore_fl); - pv_irq_ops.irq_disable = PV_CALLEE_SAVE(lguest_irq_disable); - pv_irq_ops.irq_enable = __PV_IS_CALLEE_SAVE(lg_irq_enable); - pv_irq_ops.safe_halt = lguest_safe_halt; - - /* Setup operations */ - pv_init_ops.patch = lguest_patch; - - /* Intercepts of various CPU instructions */ - pv_cpu_ops.load_gdt = lguest_load_gdt; - pv_cpu_ops.cpuid = lguest_cpuid; - pv_cpu_ops.load_idt = lguest_load_idt; - pv_cpu_ops.iret = lguest_iret; - pv_cpu_ops.load_sp0 = lguest_load_sp0; - pv_cpu_ops.load_tr_desc = lguest_load_tr_desc; - pv_cpu_ops.set_ldt = lguest_set_ldt; - pv_cpu_ops.load_tls = lguest_load_tls; - pv_cpu_ops.get_debugreg = lguest_get_debugreg; - pv_cpu_ops.set_debugreg = lguest_set_debugreg; - pv_cpu_ops.read_cr0 = lguest_read_cr0; - pv_cpu_ops.write_cr0 = lguest_write_cr0; - pv_cpu_ops.read_cr4 = lguest_read_cr4; - pv_cpu_ops.write_cr4 = lguest_write_cr4; - pv_cpu_ops.write_gdt_entry = lguest_write_gdt_entry; - pv_cpu_ops.write_idt_entry = lguest_write_idt_entry; - pv_cpu_ops.wbinvd = lguest_wbinvd; - pv_cpu_ops.start_context_switch = paravirt_start_context_switch; - pv_cpu_ops.end_context_switch = lguest_end_context_switch; - - /* Pagetable management */ - pv_mmu_ops.write_cr3 = lguest_write_cr3; - pv_mmu_ops.flush_tlb_user = lguest_flush_tlb_user; - pv_mmu_ops.flush_tlb_single = lguest_flush_tlb_single; - pv_mmu_ops.flush_tlb_kernel = lguest_flush_tlb_kernel; - pv_mmu_ops.set_pte = lguest_set_pte; - pv_mmu_ops.set_pte_at = lguest_set_pte_at; - pv_mmu_ops.set_pmd = lguest_set_pmd; -#ifdef CONFIG_X86_PAE - pv_mmu_ops.set_pte_atomic = lguest_set_pte_atomic; - pv_mmu_ops.pte_clear = lguest_pte_clear; - pv_mmu_ops.pmd_clear = lguest_pmd_clear; - pv_mmu_ops.set_pud = lguest_set_pud; -#endif - pv_mmu_ops.read_cr2 = lguest_read_cr2; - pv_mmu_ops.read_cr3 = lguest_read_cr3; - pv_mmu_ops.lazy_mode.enter = paravirt_enter_lazy_mmu; - pv_mmu_ops.lazy_mode.leave = lguest_leave_lazy_mmu_mode; - pv_mmu_ops.lazy_mode.flush = paravirt_flush_lazy_mmu; - pv_mmu_ops.pte_update = lguest_pte_update; - -#ifdef CONFIG_X86_LOCAL_APIC - /* APIC read/write intercepts */ - set_lguest_basic_apic_ops(); -#endif - - x86_init.resources.memory_setup = lguest_memory_setup; - x86_init.irqs.intr_init = lguest_init_IRQ; - x86_init.timers.timer_init = lguest_time_init; - x86_platform.calibrate_tsc = lguest_tsc_khz; - x86_platform.get_wallclock = lguest_get_wallclock; - - /* - * Now is a good time to look at the implementations of these functions - * before returning to the rest of lguest_init(). - */ - - /*G:070 - * Now we've seen all the paravirt_ops, we return to - * lguest_init() where the rest of the fairly chaotic boot setup - * occurs. - */ - - /* - * The stack protector is a weird thing where gcc places a canary - * value on the stack and then checks it on return. This file is - * compiled with -fno-stack-protector it, so we got this far without - * problems. The value of the canary is kept at offset 20 from the - * %gs register, so we need to set that up before calling C functions - * in other files. - */ - setup_stack_canary_segment(0); - - /* - * We could just call load_stack_canary_segment(), but we might as well - * call switch_to_new_gdt() which loads the whole table and sets up the - * per-cpu segment descriptor register %fs as well. - */ - switch_to_new_gdt(0); - - /* - * The Host<->Guest Switcher lives at the top of our address space, and - * the Host told us how big it is when we made LGUEST_INIT hypercall: - * it put the answer in lguest_data.reserve_mem - */ - reserve_top_address(lguest_data.reserve_mem); - - /* Hook in our special panic hypercall code. */ - atomic_notifier_chain_register(&panic_notifier_list, &paniced); - - /* - * This is messy CPU setup stuff which the native boot code does before - * start_kernel, so we have to do, too: - */ - cpu_detect(&new_cpu_data); - /* head.S usually sets up the first capability word, so do it here. */ - new_cpu_data.x86_capability[CPUID_1_EDX] = cpuid_edx(1); - - /* Math is always hard! */ - set_cpu_cap(&new_cpu_data, X86_FEATURE_FPU); - - /* We don't have features. We have puppies! Puppies! */ -#ifdef CONFIG_X86_MCE - mca_cfg.disabled = true; -#endif -#ifdef CONFIG_ACPI - acpi_disabled = 1; -#endif - - /* - * We set the preferred console to "hvc". This is the "hypervisor - * virtual console" driver written by the PowerPC people, which we also - * adapted for lguest's use. - */ - add_preferred_console("hvc", 0, NULL); - - /* Register our very early console. */ - virtio_cons_early_init(early_put_chars); - - /* Don't let ACPI try to control our PCI interrupts. */ - disable_acpi(); - - /* We control them ourselves, by overriding these two hooks. */ - pcibios_enable_irq = lguest_enable_irq; - pcibios_disable_irq = lguest_disable_irq; - - /* - * Last of all, we set the power management poweroff hook to point to - * the Guest routine to power off, and the reboot hook to our restart - * routine. - */ - pm_power_off = lguest_power_off; - machine_ops.restart = lguest_restart; - - /* - * Now we're set up, call i386_start_kernel() in head32.c and we proceed - * to boot as normal. It never returns. - */ - i386_start_kernel(); -} -/* - * This marks the end of stage II of our journey, The Guest. - * - * It is now time for us to explore the layer of virtual drivers and complete - * our understanding of the Guest in "make Drivers". - */ diff --git a/arch/x86/lguest/head_32.S b/arch/x86/lguest/head_32.S deleted file mode 100644 index d5ae63f5ec5d..000000000000 --- a/arch/x86/lguest/head_32.S +++ /dev/null @@ -1,192 +0,0 @@ -#include <linux/linkage.h> -#include <linux/lguest.h> -#include <asm/lguest_hcall.h> -#include <asm/asm-offsets.h> -#include <asm/thread_info.h> -#include <asm/processor-flags.h> - -/*G:020 - - * Our story starts with the bzImage: booting starts at startup_32 in - * arch/x86/boot/compressed/head_32.S. This merely uncompresses the real - * kernel in place and then jumps into it: startup_32 in - * arch/x86/kernel/head_32.S. Both routines expects a boot header in the %esi - * register, which is created by the bootloader (the Launcher in our case). - * - * The startup_32 function does very little: it clears the uninitialized global - * C variables which we expect to be zero (ie. BSS) and then copies the boot - * header and kernel command line somewhere safe, and populates some initial - * page tables. Finally it checks the 'hardware_subarch' field. This was - * introduced in 2.6.24 for lguest and Xen: if it's set to '1' (lguest's - * assigned number), then it calls us here. - * - * WARNING: be very careful here! We're running at addresses equal to physical - * addresses (around 0), not above PAGE_OFFSET as most code expects - * (eg. 0xC0000000). Jumps are relative, so they're OK, but we can't touch any - * data without remembering to subtract __PAGE_OFFSET! - * - * The .section line puts this code in .init.text so it will be discarded after - * boot. - */ -.section .init.text, "ax", @progbits -ENTRY(lguest_entry) - /* - * We make the "initialization" hypercall now to tell the Host where - * our lguest_data struct is. - */ - movl $LHCALL_LGUEST_INIT, %eax - movl $lguest_data - __PAGE_OFFSET, %ebx - int $LGUEST_TRAP_ENTRY - - /* Now turn our pagetables on; setup by arch/x86/kernel/head_32.S. */ - movl $LHCALL_NEW_PGTABLE, %eax - movl $(initial_page_table - __PAGE_OFFSET), %ebx - int $LGUEST_TRAP_ENTRY - - /* Set up the initial stack so we can run C code. */ - movl $(init_thread_union+THREAD_SIZE),%esp - - /* Jumps are relative: we're running __PAGE_OFFSET too low. */ - jmp lguest_init+__PAGE_OFFSET - -/*G:055 - * We create a macro which puts the assembler code between lgstart_ and lgend_ - * markers. These templates are put in the .text section: they can't be - * discarded after boot as we may need to patch modules, too. - */ -.text -#define LGUEST_PATCH(name, insns...) \ - lgstart_##name: insns; lgend_##name:; \ - .globl lgstart_##name; .globl lgend_##name - -LGUEST_PATCH(cli, movl $0, lguest_data+LGUEST_DATA_irq_enabled) -LGUEST_PATCH(pushf, movl lguest_data+LGUEST_DATA_irq_enabled, %eax) - -/*G:033 - * But using those wrappers is inefficient (we'll see why that doesn't matter - * for save_fl and irq_disable later). If we write our routines carefully in - * assembler, we can avoid clobbering any registers and avoid jumping through - * the wrapper functions. - * - * I skipped over our first piece of assembler, but this one is worth studying - * in a bit more detail so I'll describe in easy stages. First, the routine to - * enable interrupts: - */ -ENTRY(lg_irq_enable) - /* - * The reverse of irq_disable, this sets lguest_data.irq_enabled to - * X86_EFLAGS_IF (ie. "Interrupts enabled"). - */ - movl $X86_EFLAGS_IF, lguest_data+LGUEST_DATA_irq_enabled - /* - * But now we need to check if the Host wants to know: there might have - * been interrupts waiting to be delivered, in which case it will have - * set lguest_data.irq_pending to X86_EFLAGS_IF. If it's not zero, we - * jump to send_interrupts, otherwise we're done. - */ - cmpl $0, lguest_data+LGUEST_DATA_irq_pending - jnz send_interrupts - /* - * One cool thing about x86 is that you can do many things without using - * a register. In this case, the normal path hasn't needed to save or - * restore any registers at all! - */ - ret -send_interrupts: - /* - * OK, now we need a register: eax is used for the hypercall number, - * which is LHCALL_SEND_INTERRUPTS. - * - * We used not to bother with this pending detection at all, which was - * much simpler. Sooner or later the Host would realize it had to - * send us an interrupt. But that turns out to make performance 7 - * times worse on a simple tcp benchmark. So now we do this the hard - * way. - */ - pushl %eax - movl $LHCALL_SEND_INTERRUPTS, %eax - /* This is the actual hypercall trap. */ - int $LGUEST_TRAP_ENTRY - /* Put eax back the way we found it. */ - popl %eax - ret - -/* - * Finally, the "popf" or "restore flags" routine. The %eax register holds the - * flags (in practice, either X86_EFLAGS_IF or 0): if it's X86_EFLAGS_IF we're - * enabling interrupts again, if it's 0 we're leaving them off. - */ -ENTRY(lg_restore_fl) - /* This is just "lguest_data.irq_enabled = flags;" */ - movl %eax, lguest_data+LGUEST_DATA_irq_enabled - /* - * Now, if the %eax value has enabled interrupts and - * lguest_data.irq_pending is set, we want to tell the Host so it can - * deliver any outstanding interrupts. Fortunately, both values will - * be X86_EFLAGS_IF (ie. 512) in that case, and the "testl" - * instruction will AND them together for us. If both are set, we - * jump to send_interrupts. - */ - testl lguest_data+LGUEST_DATA_irq_pending, %eax - jnz send_interrupts - /* Again, the normal path has used no extra registers. Clever, huh? */ - ret -/*:*/ - -/* These demark the EIP where host should never deliver interrupts. */ -.global lguest_noirq_iret - -/*M:004 - * When the Host reflects a trap or injects an interrupt into the Guest, it - * sets the eflags interrupt bit on the stack based on lguest_data.irq_enabled, - * so the Guest iret logic does the right thing when restoring it. However, - * when the Host sets the Guest up for direct traps, such as system calls, the - * processor is the one to push eflags onto the stack, and the interrupt bit - * will be 1 (in reality, interrupts are always enabled in the Guest). - * - * This turns out to be harmless: the only trap which should happen under Linux - * with interrupts disabled is Page Fault (due to our lazy mapping of vmalloc - * regions), which has to be reflected through the Host anyway. If another - * trap *does* go off when interrupts are disabled, the Guest will panic, and - * we'll never get to this iret! -:*/ - -/*G:045 - * There is one final paravirt_op that the Guest implements, and glancing at it - * you can see why I left it to last. It's *cool*! It's in *assembler*! - * - * The "iret" instruction is used to return from an interrupt or trap. The - * stack looks like this: - * old address - * old code segment & privilege level - * old processor flags ("eflags") - * - * The "iret" instruction pops those values off the stack and restores them all - * at once. The only problem is that eflags includes the Interrupt Flag which - * the Guest can't change: the CPU will simply ignore it when we do an "iret". - * So we have to copy eflags from the stack to lguest_data.irq_enabled before - * we do the "iret". - * - * There are two problems with this: firstly, we can't clobber any registers - * and secondly, the whole thing needs to be atomic. The first problem - * is solved by using "push memory"/"pop memory" instruction pair for copying. - * - * The second is harder: copying eflags to lguest_data.irq_enabled will turn - * interrupts on before we're finished, so we could be interrupted before we - * return to userspace or wherever. Our solution to this is to tell the - * Host that it is *never* to interrupt us there, even if interrupts seem to be - * enabled. (It's not necessary to protect pop instruction, since - * data gets updated only after it completes, so we only need to protect - * one instruction, iret). - */ -ENTRY(lguest_iret) - pushl 2*4(%esp) - /* - * Note the %ss: segment prefix here. Normal data accesses use the - * "ds" segment, but that will have already been restored for whatever - * we're returning to (such as userspace): we can't trust it. The %ss: - * prefix makes sure we use the stack segment, which is still valid. - */ - popl %ss:lguest_data+LGUEST_DATA_irq_enabled -lguest_noirq_iret: - iret diff --git a/arch/x86/math-emu/div_Xsig.S b/arch/x86/math-emu/div_Xsig.S index f77ba3058b31..066996dba6a2 100644 --- a/arch/x86/math-emu/div_Xsig.S +++ b/arch/x86/math-emu/div_Xsig.S @@ -363,3 +363,4 @@ L_bugged_2: pop %ebx jmp L_exit #endif /* PARANOID */ +ENDPROC(div_Xsig) diff --git a/arch/x86/math-emu/div_small.S b/arch/x86/math-emu/div_small.S index 47099628fa4c..2c71527bd917 100644 --- a/arch/x86/math-emu/div_small.S +++ b/arch/x86/math-emu/div_small.S @@ -44,4 +44,4 @@ ENTRY(FPU_div_small) leave ret - +ENDPROC(FPU_div_small) diff --git a/arch/x86/math-emu/mul_Xsig.S b/arch/x86/math-emu/mul_Xsig.S index 717785a53eb4..22e0631bb85a 100644 --- a/arch/x86/math-emu/mul_Xsig.S +++ b/arch/x86/math-emu/mul_Xsig.S @@ -62,6 +62,7 @@ ENTRY(mul32_Xsig) popl %esi leave ret +ENDPROC(mul32_Xsig) ENTRY(mul64_Xsig) @@ -114,6 +115,7 @@ ENTRY(mul64_Xsig) popl %esi leave ret +ENDPROC(mul64_Xsig) @@ -173,4 +175,4 @@ ENTRY(mul_Xsig_Xsig) popl %esi leave ret - +ENDPROC(mul_Xsig_Xsig) diff --git a/arch/x86/math-emu/polynom_Xsig.S b/arch/x86/math-emu/polynom_Xsig.S index 17315c89ff3d..a9aaf414135d 100644 --- a/arch/x86/math-emu/polynom_Xsig.S +++ b/arch/x86/math-emu/polynom_Xsig.S @@ -133,3 +133,4 @@ L_accum_done: popl %esi leave ret +ENDPROC(polynomial_Xsig) diff --git a/arch/x86/math-emu/reg_norm.S b/arch/x86/math-emu/reg_norm.S index 8b6352efceef..53ac1a343c69 100644 --- a/arch/x86/math-emu/reg_norm.S +++ b/arch/x86/math-emu/reg_norm.S @@ -94,6 +94,7 @@ L_overflow: call arith_overflow pop %ebx jmp L_exit +ENDPROC(FPU_normalize) @@ -145,3 +146,4 @@ L_exit_nuo_zero: popl %ebx leave ret +ENDPROC(FPU_normalize_nuo) diff --git a/arch/x86/math-emu/reg_round.S b/arch/x86/math-emu/reg_round.S index d1d4e48b4f67..41af5b208d88 100644 --- a/arch/x86/math-emu/reg_round.S +++ b/arch/x86/math-emu/reg_round.S @@ -706,3 +706,5 @@ L_exception_exit: mov $-1,%eax jmp fpu_reg_round_special_exit #endif /* PARANOID */ + +ENDPROC(FPU_round) diff --git a/arch/x86/math-emu/reg_u_add.S b/arch/x86/math-emu/reg_u_add.S index 47c4c2434d85..3b1bc5e9b2f6 100644 --- a/arch/x86/math-emu/reg_u_add.S +++ b/arch/x86/math-emu/reg_u_add.S @@ -165,3 +165,4 @@ L_exit: leave ret #endif /* PARANOID */ +ENDPROC(FPU_u_add) diff --git a/arch/x86/math-emu/reg_u_div.S b/arch/x86/math-emu/reg_u_div.S index cc00654b6f9a..796eb5ab921b 100644 --- a/arch/x86/math-emu/reg_u_div.S +++ b/arch/x86/math-emu/reg_u_div.S @@ -469,3 +469,5 @@ L_exit: leave ret #endif /* PARANOID */ + +ENDPROC(FPU_u_div) diff --git a/arch/x86/math-emu/reg_u_mul.S b/arch/x86/math-emu/reg_u_mul.S index 973f12af97df..6196f68cf3c1 100644 --- a/arch/x86/math-emu/reg_u_mul.S +++ b/arch/x86/math-emu/reg_u_mul.S @@ -146,3 +146,4 @@ L_exit: ret #endif /* PARANOID */ +ENDPROC(FPU_u_mul) diff --git a/arch/x86/math-emu/reg_u_sub.S b/arch/x86/math-emu/reg_u_sub.S index 1b6c24801d22..d115b900919a 100644 --- a/arch/x86/math-emu/reg_u_sub.S +++ b/arch/x86/math-emu/reg_u_sub.S @@ -270,3 +270,4 @@ L_exit: popl %esi leave ret +ENDPROC(FPU_u_sub) diff --git a/arch/x86/math-emu/round_Xsig.S b/arch/x86/math-emu/round_Xsig.S index bbe0e87718e4..87c99749a495 100644 --- a/arch/x86/math-emu/round_Xsig.S +++ b/arch/x86/math-emu/round_Xsig.S @@ -78,7 +78,7 @@ L_exit: popl %ebx leave ret - +ENDPROC(round_Xsig) @@ -138,4 +138,4 @@ L_n_exit: popl %ebx leave ret - +ENDPROC(norm_Xsig) diff --git a/arch/x86/math-emu/shr_Xsig.S b/arch/x86/math-emu/shr_Xsig.S index 31cdd118e918..c8552edeec75 100644 --- a/arch/x86/math-emu/shr_Xsig.S +++ b/arch/x86/math-emu/shr_Xsig.S @@ -85,3 +85,4 @@ L_more_than_95: popl %esi leave ret +ENDPROC(shr_Xsig) diff --git a/arch/x86/math-emu/wm_shrx.S b/arch/x86/math-emu/wm_shrx.S index 518428317985..340dd6897f85 100644 --- a/arch/x86/math-emu/wm_shrx.S +++ b/arch/x86/math-emu/wm_shrx.S @@ -92,6 +92,7 @@ L_more_than_95: popl %esi leave ret +ENDPROC(FPU_shrx) /*---------------------------------------------------------------------------+ @@ -202,3 +203,4 @@ Ls_more_than_95: popl %esi leave ret +ENDPROC(FPU_shrxs) diff --git a/arch/x86/math-emu/wm_sqrt.S b/arch/x86/math-emu/wm_sqrt.S index d258f59564e1..695afae38fdf 100644 --- a/arch/x86/math-emu/wm_sqrt.S +++ b/arch/x86/math-emu/wm_sqrt.S @@ -468,3 +468,4 @@ sqrt_more_prec_large: /* Our estimate is too large */ movl $0x7fffff00,%eax jmp sqrt_round_result +ENDPROC(wm_sqrt) diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c index 0ea8afcb929c..fb2ddcdf7c73 100644 --- a/arch/x86/mm/extable.c +++ b/arch/x86/mm/extable.c @@ -142,7 +142,7 @@ void __init early_fixup_exception(struct pt_regs *regs, int trapnr) * undefined. I'm not sure which CPUs do this, but at least * the 486 DX works this way. */ - if ((regs->cs & 0xFFFF) != __KERNEL_CS) + if (regs->cs != __KERNEL_CS) goto fail; /* diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c index 811e4ddb3f37..98491521bb43 100644 --- a/arch/x86/xen/enlighten_pv.c +++ b/arch/x86/xen/enlighten_pv.c @@ -981,59 +981,6 @@ void __ref xen_setup_vcpu_info_placement(void) } } -static unsigned xen_patch(u8 type, u16 clobbers, void *insnbuf, - unsigned long addr, unsigned len) -{ - char *start, *end, *reloc; - unsigned ret; - - start = end = reloc = NULL; - -#define SITE(op, x) \ - case PARAVIRT_PATCH(op.x): \ - if (xen_have_vcpu_info_placement) { \ - start = (char *)xen_##x##_direct; \ - end = xen_##x##_direct_end; \ - reloc = xen_##x##_direct_reloc; \ - } \ - goto patch_site - - switch (type) { - SITE(pv_irq_ops, irq_enable); - SITE(pv_irq_ops, irq_disable); - SITE(pv_irq_ops, save_fl); - SITE(pv_irq_ops, restore_fl); -#undef SITE - - patch_site: - if (start == NULL || (end-start) > len) - goto default_patch; - - ret = paravirt_patch_insns(insnbuf, len, start, end); - - /* Note: because reloc is assigned from something that - appears to be an array, gcc assumes it's non-null, - but doesn't know its relationship with start and - end. */ - if (reloc > start && reloc < end) { - int reloc_off = reloc - start; - long *relocp = (long *)(insnbuf + reloc_off); - long delta = start - (char *)addr; - - *relocp += delta; - } - break; - - default_patch: - default: - ret = paravirt_patch_default(type, clobbers, insnbuf, - addr, len); - break; - } - - return ret; -} - static const struct pv_info xen_info __initconst = { .shared_kernel_pmd = 0, @@ -1043,10 +990,6 @@ static const struct pv_info xen_info __initconst = { .name = "Xen", }; -static const struct pv_init_ops xen_init_ops __initconst = { - .patch = xen_patch, -}; - static const struct pv_cpu_ops xen_cpu_ops __initconst = { .cpuid = xen_cpuid, @@ -1244,7 +1187,7 @@ asmlinkage __visible void __init xen_start_kernel(void) /* Install Xen paravirt ops */ pv_info = xen_info; - pv_init_ops = xen_init_ops; + pv_init_ops.patch = paravirt_patch_default; pv_cpu_ops = xen_cpu_ops; x86_platform.get_nmi_reason = xen_get_nmi_reason; diff --git a/arch/x86/xen/xen-asm.S b/arch/x86/xen/xen-asm.S index eff224df813f..dcd31fa39b5d 100644 --- a/arch/x86/xen/xen-asm.S +++ b/arch/x86/xen/xen-asm.S @@ -1,14 +1,8 @@ /* - * Asm versions of Xen pv-ops, suitable for either direct use or - * inlining. The inline versions are the same as the direct-use - * versions, with the pre- and post-amble chopped off. - * - * This code is encoded for size rather than absolute efficiency, with - * a view to being able to inline as much as possible. + * Asm versions of Xen pv-ops, suitable for direct use. * * We only bother with direct forms (ie, vcpu in percpu data) of the - * operations here; the indirect forms are better handled in C, since - * they're generally too large to inline anyway. + * operations here; the indirect forms are better handled in C. */ #include <asm/asm-offsets.h> @@ -16,7 +10,7 @@ #include <asm/processor-flags.h> #include <asm/frame.h> -#include "xen-asm.h" +#include <linux/linkage.h> /* * Enable events. This clears the event mask and tests the pending @@ -38,13 +32,11 @@ ENTRY(xen_irq_enable_direct) testb $0xff, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_pending jz 1f -2: call check_events + call check_events 1: -ENDPATCH(xen_irq_enable_direct) FRAME_END ret ENDPROC(xen_irq_enable_direct) - RELOC(xen_irq_enable_direct, 2b+1) /* @@ -53,10 +45,8 @@ ENDPATCH(xen_irq_enable_direct) */ ENTRY(xen_irq_disable_direct) movb $1, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask -ENDPATCH(xen_irq_disable_direct) ret - ENDPROC(xen_irq_disable_direct) - RELOC(xen_irq_disable_direct, 0) +ENDPROC(xen_irq_disable_direct) /* * (xen_)save_fl is used to get the current interrupt enable status. @@ -71,10 +61,8 @@ ENTRY(xen_save_fl_direct) testb $0xff, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask setz %ah addb %ah, %ah -ENDPATCH(xen_save_fl_direct) ret ENDPROC(xen_save_fl_direct) - RELOC(xen_save_fl_direct, 0) /* @@ -101,13 +89,11 @@ ENTRY(xen_restore_fl_direct) /* check for unmasked and pending */ cmpw $0x0001, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_pending jnz 1f -2: call check_events + call check_events 1: -ENDPATCH(xen_restore_fl_direct) FRAME_END ret ENDPROC(xen_restore_fl_direct) - RELOC(xen_restore_fl_direct, 2b+1) /* diff --git a/arch/x86/xen/xen-asm.h b/arch/x86/xen/xen-asm.h deleted file mode 100644 index 465276467a47..000000000000 --- a/arch/x86/xen/xen-asm.h +++ /dev/null @@ -1,12 +0,0 @@ -#ifndef _XEN_XEN_ASM_H -#define _XEN_XEN_ASM_H - -#include <linux/linkage.h> - -#define RELOC(x, v) .globl x##_reloc; x##_reloc=v -#define ENDPATCH(x) .globl x##_end; x##_end=. - -/* Pseudo-flag used for virtual NMI, which we don't implement yet */ -#define XEN_EFLAGS_NMI 0x80000000 - -#endif diff --git a/arch/x86/xen/xen-asm_32.S b/arch/x86/xen/xen-asm_32.S index feb6d40a0860..1200e262a116 100644 --- a/arch/x86/xen/xen-asm_32.S +++ b/arch/x86/xen/xen-asm_32.S @@ -1,14 +1,8 @@ /* - * Asm versions of Xen pv-ops, suitable for either direct use or - * inlining. The inline versions are the same as the direct-use - * versions, with the pre- and post-amble chopped off. - * - * This code is encoded for size rather than absolute efficiency, with - * a view to being able to inline as much as possible. + * Asm versions of Xen pv-ops, suitable for direct use. * * We only bother with direct forms (ie, vcpu in pda) of the - * operations here; the indirect forms are better handled in C, since - * they're generally too large to inline anyway. + * operations here; the indirect forms are better handled in C. */ #include <asm/thread_info.h> @@ -18,21 +12,10 @@ #include <xen/interface/xen.h> -#include "xen-asm.h" +#include <linux/linkage.h> -/* - * Force an event check by making a hypercall, but preserve regs - * before making the call. - */ -check_events: - push %eax - push %ecx - push %edx - call xen_force_evtchn_callback - pop %edx - pop %ecx - pop %eax - ret +/* Pseudo-flag used for virtual NMI, which we don't implement yet */ +#define XEN_EFLAGS_NMI 0x80000000 /* * This is run where a normal iret would be run, with the same stack setup: diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S index c3df43141e70..3a3b6a211584 100644 --- a/arch/x86/xen/xen-asm_64.S +++ b/arch/x86/xen/xen-asm_64.S @@ -1,14 +1,8 @@ /* - * Asm versions of Xen pv-ops, suitable for either direct use or - * inlining. The inline versions are the same as the direct-use - * versions, with the pre- and post-amble chopped off. - * - * This code is encoded for size rather than absolute efficiency, with - * a view to being able to inline as much as possible. + * Asm versions of Xen pv-ops, suitable for direct use. * * We only bother with direct forms (ie, vcpu in pda) of the - * operations here; the indirect forms are better handled in C, since - * they're generally too large to inline anyway. + * operations here; the indirect forms are better handled in C. */ #include <asm/errno.h> @@ -20,7 +14,7 @@ #include <xen/interface/xen.h> -#include "xen-asm.h" +#include <linux/linkage.h> ENTRY(xen_adjust_exception_frame) mov 8+0(%rsp), %rcx @@ -46,9 +40,7 @@ hypercall_iret = hypercall_page + __HYPERVISOR_iret * 32 */ ENTRY(xen_iret) pushq $0 -1: jmp hypercall_iret -ENDPATCH(xen_iret) -RELOC(xen_iret, 1b+1) + jmp hypercall_iret ENTRY(xen_sysret64) /* @@ -65,9 +57,7 @@ ENTRY(xen_sysret64) pushq %rcx pushq $VGCF_in_syscall -1: jmp hypercall_iret -ENDPATCH(xen_sysret64) -RELOC(xen_sysret64, 1b+1) + jmp hypercall_iret /* * Xen handles syscall callbacks much like ordinary exceptions, which @@ -82,34 +72,47 @@ RELOC(xen_sysret64, 1b+1) * rip * r11 * rsp->rcx - * - * In all the entrypoints, we undo all that to make it look like a - * CPU-generated syscall/sysenter and jump to the normal entrypoint. */ -.macro undo_xen_syscall - mov 0*8(%rsp), %rcx - mov 1*8(%rsp), %r11 - mov 5*8(%rsp), %rsp -.endm - /* Normal 64-bit system call target */ ENTRY(xen_syscall_target) - undo_xen_syscall - jmp entry_SYSCALL_64_after_swapgs + popq %rcx + popq %r11 + + /* + * Neither Xen nor the kernel really knows what the old SS and + * CS were. The kernel expects __USER_DS and __USER_CS, so + * report those values even though Xen will guess its own values. + */ + movq $__USER_DS, 4*8(%rsp) + movq $__USER_CS, 1*8(%rsp) + + jmp entry_SYSCALL_64_after_hwframe ENDPROC(xen_syscall_target) #ifdef CONFIG_IA32_EMULATION /* 32-bit compat syscall target */ ENTRY(xen_syscall32_target) - undo_xen_syscall - jmp entry_SYSCALL_compat + popq %rcx + popq %r11 + + /* + * Neither Xen nor the kernel really knows what the old SS and + * CS were. The kernel expects __USER32_DS and __USER32_CS, so + * report those values even though Xen will guess its own values. + */ + movq $__USER32_DS, 4*8(%rsp) + movq $__USER32_CS, 1*8(%rsp) + + jmp entry_SYSCALL_compat_after_hwframe ENDPROC(xen_syscall32_target) /* 32-bit compat sysenter target */ ENTRY(xen_sysenter_target) - undo_xen_syscall + mov 0*8(%rsp), %rcx + mov 1*8(%rsp), %r11 + mov 5*8(%rsp), %rsp jmp entry_SYSENTER_compat ENDPROC(xen_sysenter_target) diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h index 0d5004477db6..70301ac0d414 100644 --- a/arch/x86/xen/xen-ops.h +++ b/arch/x86/xen/xen-ops.h @@ -129,17 +129,10 @@ static inline void __init xen_efi_init(void) } #endif -/* Declare an asm function, along with symbols needed to make it - inlineable */ -#define DECL_ASM(ret, name, ...) \ - __visible ret name(__VA_ARGS__); \ - extern char name##_end[] __visible; \ - extern char name##_reloc[] __visible - -DECL_ASM(void, xen_irq_enable_direct, void); -DECL_ASM(void, xen_irq_disable_direct, void); -DECL_ASM(unsigned long, xen_save_fl_direct, void); -DECL_ASM(void, xen_restore_fl_direct, unsigned long); +__visible void xen_irq_enable_direct(void); +__visible void xen_irq_disable_direct(void); +__visible unsigned long xen_save_fl_direct(void); +__visible void xen_restore_fl_direct(unsigned long); /* These are not functions, and cannot be called normally */ __visible void xen_iret(void); |