diff options
Diffstat (limited to 'arch/x86/mm/fault.c')
| -rw-r--r-- | arch/x86/mm/fault.c | 81 |
1 files changed, 30 insertions, 51 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 46df4c6aae46..6c46095cd0d9 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -46,23 +46,6 @@ kmmio_fault(struct pt_regs *regs, unsigned long addr) return 0; } -static nokprobe_inline int kprobes_fault(struct pt_regs *regs) -{ - if (!kprobes_built_in()) - return 0; - if (user_mode(regs)) - return 0; - /* - * To be potentially processing a kprobe fault and to be allowed to call - * kprobe_running(), we have to be non-preemptible. - */ - if (preemptible()) - return 0; - if (!kprobe_running()) - return 0; - return kprobe_fault_handler(regs, X86_TRAP_PF); -} - /* * Prefetch quirks: * @@ -710,6 +693,10 @@ static void set_signal_archinfo(unsigned long address, * To avoid leaking information about the kernel page * table layout, pretend that user-mode accesses to * kernel addresses are always protection faults. + * + * NB: This means that failed vsyscalls with vsyscall=none + * will have the PROT bit. This doesn't leak any + * information and does not appear to cause any problems. */ if (address >= TASK_SIZE_MAX) error_code |= X86_PF_PROT; @@ -756,8 +743,7 @@ no_context(struct pt_regs *regs, unsigned long error_code, set_signal_archinfo(address, error_code); /* XXX: hwpoison faults will set the wrong code. */ - force_sig_fault(signal, si_code, (void __user *)address, - tsk); + force_sig_fault(signal, si_code, (void __user *)address); } /* @@ -918,7 +904,7 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code, if (si_code == SEGV_PKUERR) force_sig_pkuerr((void __user *)address, pkey); - force_sig_fault(SIGSEGV, si_code, (void __user *)address, tsk); + force_sig_fault(SIGSEGV, si_code, (void __user *)address); return; } @@ -1015,8 +1001,6 @@ static void do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address, vm_fault_t fault) { - struct task_struct *tsk = current; - /* Kernel mode? Handle exceptions or die: */ if (!(error_code & X86_PF_USER)) { no_context(regs, error_code, address, SIGBUS, BUS_ADRERR); @@ -1031,6 +1015,7 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address, #ifdef CONFIG_MEMORY_FAILURE if (fault & (VM_FAULT_HWPOISON|VM_FAULT_HWPOISON_LARGE)) { + struct task_struct *tsk = current; unsigned lsb = 0; pr_err( @@ -1040,11 +1025,11 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address, lsb = hstate_index_to_shift(VM_FAULT_GET_HINDEX(fault)); if (fault & VM_FAULT_HWPOISON) lsb = PAGE_SHIFT; - force_sig_mceerr(BUS_MCEERR_AR, (void __user *)address, lsb, tsk); + force_sig_mceerr(BUS_MCEERR_AR, (void __user *)address, lsb); return; } #endif - force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)address, tsk); + force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)address); } static noinline void @@ -1280,7 +1265,7 @@ do_kern_addr_fault(struct pt_regs *regs, unsigned long hw_error_code, return; /* kprobes don't want to hook the spurious faults: */ - if (kprobes_fault(regs)) + if (kprobe_page_fault(regs, X86_TRAP_PF)) return; /* @@ -1311,7 +1296,7 @@ void do_user_addr_fault(struct pt_regs *regs, mm = tsk->mm; /* kprobes don't want to hook the spurious faults: */ - if (unlikely(kprobes_fault(regs))) + if (unlikely(kprobe_page_fault(regs, X86_TRAP_PF))) return; /* @@ -1369,16 +1354,18 @@ void do_user_addr_fault(struct pt_regs *regs, #ifdef CONFIG_X86_64 /* - * Instruction fetch faults in the vsyscall page might need - * emulation. The vsyscall page is at a high address - * (>PAGE_OFFSET), but is considered to be part of the user - * address space. + * Faults in the vsyscall page might need emulation. The + * vsyscall page is at a high address (>PAGE_OFFSET), but is + * considered to be part of the user address space. * * The vsyscall page does not have a "real" VMA, so do this * emulation before we go searching for VMAs. + * + * PKRU never rejects instruction fetches, so we don't need + * to consider the PF_PK bit. */ - if ((hw_error_code & X86_PF_INSTR) && is_vsyscall_vaddr(address)) { - if (emulate_vsyscall(regs, address)) + if (is_vsyscall_vaddr(address)) { + if (emulate_vsyscall(hw_error_code, regs, address)) return; } #endif @@ -1503,9 +1490,8 @@ good_area: NOKPROBE_SYMBOL(do_user_addr_fault); /* - * This routine handles page faults. It determines the address, - * and the problem, and then passes it off to one of the appropriate - * routines. + * Explicitly marked noinline such that the function tracer sees this as the + * page_fault entry point. */ static noinline void __do_page_fault(struct pt_regs *regs, unsigned long hw_error_code, @@ -1524,33 +1510,26 @@ __do_page_fault(struct pt_regs *regs, unsigned long hw_error_code, } NOKPROBE_SYMBOL(__do_page_fault); -static nokprobe_inline void -trace_page_fault_entries(unsigned long address, struct pt_regs *regs, - unsigned long error_code) +static __always_inline void +trace_page_fault_entries(struct pt_regs *regs, unsigned long error_code, + unsigned long address) { + if (!trace_pagefault_enabled()) + return; + if (user_mode(regs)) trace_page_fault_user(address, regs, error_code); else trace_page_fault_kernel(address, regs, error_code); } -/* - * We must have this function blacklisted from kprobes, tagged with notrace - * and call read_cr2() before calling anything else. To avoid calling any - * kind of tracing machinery before we've observed the CR2 value. - * - * exception_{enter,exit}() contains all sorts of tracepoints. - */ -dotraplinkage void notrace -do_page_fault(struct pt_regs *regs, unsigned long error_code) +dotraplinkage void +do_page_fault(struct pt_regs *regs, unsigned long error_code, unsigned long address) { - unsigned long address = read_cr2(); /* Get the faulting address */ enum ctx_state prev_state; prev_state = exception_enter(); - if (trace_pagefault_enabled()) - trace_page_fault_entries(address, regs, error_code); - + trace_page_fault_entries(regs, error_code, address); __do_page_fault(regs, error_code, address); exception_exit(prev_state); } |