diff options
Diffstat (limited to 'arch/sparc64/mm/fault.c')
| -rw-r--r-- | arch/sparc64/mm/fault.c | 527 |
1 files changed, 527 insertions, 0 deletions
diff --git a/arch/sparc64/mm/fault.c b/arch/sparc64/mm/fault.c new file mode 100644 index 000000000000..3ffee7b51aed --- /dev/null +++ b/arch/sparc64/mm/fault.c @@ -0,0 +1,527 @@ +/* $Id: fault.c,v 1.59 2002/02/09 19:49:31 davem Exp $ + * arch/sparc64/mm/fault.c: Page fault handlers for the 64-bit Sparc. + * + * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu) + * Copyright (C) 1997, 1999 Jakub Jelinek (jj@ultra.linux.cz) + */ + +#include <asm/head.h> + +#include <linux/string.h> +#include <linux/types.h> +#include <linux/sched.h> +#include <linux/ptrace.h> +#include <linux/mman.h> +#include <linux/signal.h> +#include <linux/mm.h> +#include <linux/module.h> +#include <linux/smp_lock.h> +#include <linux/init.h> +#include <linux/interrupt.h> + +#include <asm/page.h> +#include <asm/pgtable.h> +#include <asm/openprom.h> +#include <asm/oplib.h> +#include <asm/uaccess.h> +#include <asm/asi.h> +#include <asm/lsu.h> +#include <asm/sections.h> +#include <asm/kdebug.h> + +#define ELEMENTS(arr) (sizeof (arr)/sizeof (arr[0])) + +extern struct sparc_phys_banks sp_banks[SPARC_PHYS_BANKS]; + +/* + * To debug kernel during syscall entry. + */ +void syscall_trace_entry(struct pt_regs *regs) +{ + printk("scall entry: %s[%d]/cpu%d: %d\n", current->comm, current->pid, smp_processor_id(), (int) regs->u_regs[UREG_G1]); +} + +/* + * To debug kernel during syscall exit. + */ +void syscall_trace_exit(struct pt_regs *regs) +{ + printk("scall exit: %s[%d]/cpu%d: %d\n", current->comm, current->pid, smp_processor_id(), (int) regs->u_regs[UREG_G1]); +} + +/* + * To debug kernel to catch accesses to certain virtual/physical addresses. + * Mode = 0 selects physical watchpoints, mode = 1 selects virtual watchpoints. + * flags = VM_READ watches memread accesses, flags = VM_WRITE watches memwrite accesses. + * Caller passes in a 64bit aligned addr, with mask set to the bytes that need to be + * watched. This is only useful on a single cpu machine for now. After the watchpoint + * is detected, the process causing it will be killed, thus preventing an infinite loop. + */ +void set_brkpt(unsigned long addr, unsigned char mask, int flags, int mode) +{ + unsigned long lsubits; + + __asm__ __volatile__("ldxa [%%g0] %1, %0" + : "=r" (lsubits) + : "i" (ASI_LSU_CONTROL)); + lsubits &= ~(LSU_CONTROL_PM | LSU_CONTROL_VM | + LSU_CONTROL_PR | LSU_CONTROL_VR | + LSU_CONTROL_PW | LSU_CONTROL_VW); + + __asm__ __volatile__("stxa %0, [%1] %2\n\t" + "membar #Sync" + : /* no outputs */ + : "r" (addr), "r" (mode ? VIRT_WATCHPOINT : PHYS_WATCHPOINT), + "i" (ASI_DMMU)); + + lsubits |= ((unsigned long)mask << (mode ? 25 : 33)); + if (flags & VM_READ) + lsubits |= (mode ? LSU_CONTROL_VR : LSU_CONTROL_PR); + if (flags & VM_WRITE) + lsubits |= (mode ? LSU_CONTROL_VW : LSU_CONTROL_PW); + __asm__ __volatile__("stxa %0, [%%g0] %1\n\t" + "membar #Sync" + : /* no outputs */ + : "r" (lsubits), "i" (ASI_LSU_CONTROL) + : "memory"); +} + +/* Nice, simple, prom library does all the sweating for us. ;) */ +unsigned long __init prom_probe_memory (void) +{ + register struct linux_mlist_p1275 *mlist; + register unsigned long bytes, base_paddr, tally; + register int i; + + i = 0; + mlist = *prom_meminfo()->p1275_available; + bytes = tally = mlist->num_bytes; + base_paddr = mlist->start_adr; + + sp_banks[0].base_addr = base_paddr; + sp_banks[0].num_bytes = bytes; + + while (mlist->theres_more != (void *) 0) { + i++; + mlist = mlist->theres_more; + bytes = mlist->num_bytes; + tally += bytes; + if (i >= SPARC_PHYS_BANKS-1) { + printk ("The machine has more banks than " + "this kernel can support\n" + "Increase the SPARC_PHYS_BANKS " + "setting (currently %d)\n", + SPARC_PHYS_BANKS); + i = SPARC_PHYS_BANKS-1; + break; + } + + sp_banks[i].base_addr = mlist->start_adr; + sp_banks[i].num_bytes = mlist->num_bytes; + } + + i++; + sp_banks[i].base_addr = 0xdeadbeefbeefdeadUL; + sp_banks[i].num_bytes = 0; + + /* Now mask all bank sizes on a page boundary, it is all we can + * use anyways. + */ + for (i = 0; sp_banks[i].num_bytes != 0; i++) + sp_banks[i].num_bytes &= PAGE_MASK; + + return tally; +} + +static void unhandled_fault(unsigned long address, struct task_struct *tsk, + struct pt_regs *regs) +{ + if ((unsigned long) address < PAGE_SIZE) { + printk(KERN_ALERT "Unable to handle kernel NULL " + "pointer dereference\n"); + } else { + printk(KERN_ALERT "Unable to handle kernel paging request " + "at virtual address %016lx\n", (unsigned long)address); + } + printk(KERN_ALERT "tsk->{mm,active_mm}->context = %016lx\n", + (tsk->mm ? + CTX_HWBITS(tsk->mm->context) : + CTX_HWBITS(tsk->active_mm->context))); + printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %016lx\n", + (tsk->mm ? (unsigned long) tsk->mm->pgd : + (unsigned long) tsk->active_mm->pgd)); + if (notify_die(DIE_GPF, "general protection fault", regs, + 0, 0, SIGSEGV) == NOTIFY_STOP) + return; + die_if_kernel("Oops", regs); +} + +static void bad_kernel_pc(struct pt_regs *regs) +{ + unsigned long *ksp; + + printk(KERN_CRIT "OOPS: Bogus kernel PC [%016lx] in fault handler\n", + regs->tpc); + __asm__("mov %%sp, %0" : "=r" (ksp)); + show_stack(current, ksp); + unhandled_fault(regs->tpc, current, regs); +} + +/* + * We now make sure that mmap_sem is held in all paths that call + * this. Additionally, to prevent kswapd from ripping ptes from + * under us, raise interrupts around the time that we look at the + * pte, kswapd will have to wait to get his smp ipi response from + * us. This saves us having to get page_table_lock. + */ +static unsigned int get_user_insn(unsigned long tpc) +{ + pgd_t *pgdp = pgd_offset(current->mm, tpc); + pud_t *pudp; + pmd_t *pmdp; + pte_t *ptep, pte; + unsigned long pa; + u32 insn = 0; + unsigned long pstate; + + if (pgd_none(*pgdp)) + goto outret; + pudp = pud_offset(pgdp, tpc); + if (pud_none(*pudp)) + goto outret; + pmdp = pmd_offset(pudp, tpc); + if (pmd_none(*pmdp)) + goto outret; + + /* This disables preemption for us as well. */ + __asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate)); + __asm__ __volatile__("wrpr %0, %1, %%pstate" + : : "r" (pstate), "i" (PSTATE_IE)); + ptep = pte_offset_map(pmdp, tpc); + pte = *ptep; + if (!pte_present(pte)) + goto out; + + pa = (pte_val(pte) & _PAGE_PADDR); + pa += (tpc & ~PAGE_MASK); + + /* Use phys bypass so we don't pollute dtlb/dcache. */ + __asm__ __volatile__("lduwa [%1] %2, %0" + : "=r" (insn) + : "r" (pa), "i" (ASI_PHYS_USE_EC)); + +out: + pte_unmap(ptep); + __asm__ __volatile__("wrpr %0, 0x0, %%pstate" : : "r" (pstate)); +outret: + return insn; +} + +extern unsigned long compute_effective_address(struct pt_regs *, unsigned int, unsigned int); + +static void do_fault_siginfo(int code, int sig, struct pt_regs *regs, + unsigned int insn, int fault_code) +{ + siginfo_t info; + + info.si_code = code; + info.si_signo = sig; + info.si_errno = 0; + if (fault_code & FAULT_CODE_ITLB) + info.si_addr = (void __user *) regs->tpc; + else + info.si_addr = (void __user *) + compute_effective_address(regs, insn, 0); + info.si_trapno = 0; + force_sig_info(sig, &info, current); +} + +extern int handle_ldf_stq(u32, struct pt_regs *); +extern int handle_ld_nf(u32, struct pt_regs *); + +static unsigned int get_fault_insn(struct pt_regs *regs, unsigned int insn) +{ + if (!insn) { + if (!regs->tpc || (regs->tpc & 0x3)) + return 0; + if (regs->tstate & TSTATE_PRIV) { + insn = *(unsigned int *) regs->tpc; + } else { + insn = get_user_insn(regs->tpc); + } + } + return insn; +} + +static void do_kernel_fault(struct pt_regs *regs, int si_code, int fault_code, + unsigned int insn, unsigned long address) +{ + unsigned long g2; + unsigned char asi = ASI_P; + + if ((!insn) && (regs->tstate & TSTATE_PRIV)) + goto cannot_handle; + + /* If user insn could be read (thus insn is zero), that + * is fine. We will just gun down the process with a signal + * in that case. + */ + + if (!(fault_code & (FAULT_CODE_WRITE|FAULT_CODE_ITLB)) && + (insn & 0xc0800000) == 0xc0800000) { + if (insn & 0x2000) + asi = (regs->tstate >> 24); + else + asi = (insn >> 5); + if ((asi & 0xf2) == 0x82) { + if (insn & 0x1000000) { + handle_ldf_stq(insn, regs); + } else { + /* This was a non-faulting load. Just clear the + * destination register(s) and continue with the next + * instruction. -jj + */ + handle_ld_nf(insn, regs); + } + return; + } + } + + g2 = regs->u_regs[UREG_G2]; + + /* Is this in ex_table? */ + if (regs->tstate & TSTATE_PRIV) { + unsigned long fixup; + + if (asi == ASI_P && (insn & 0xc0800000) == 0xc0800000) { + if (insn & 0x2000) + asi = (regs->tstate >> 24); + else + asi = (insn >> 5); + } + + /* Look in asi.h: All _S asis have LS bit set */ + if ((asi & 0x1) && + (fixup = search_extables_range(regs->tpc, &g2))) { + regs->tpc = fixup; + regs->tnpc = regs->tpc + 4; + regs->u_regs[UREG_G2] = g2; + return; + } + } else { + /* The si_code was set to make clear whether + * this was a SEGV_MAPERR or SEGV_ACCERR fault. + */ + do_fault_siginfo(si_code, SIGSEGV, regs, insn, fault_code); + return; + } + +cannot_handle: + unhandled_fault (address, current, regs); +} + +asmlinkage void do_sparc64_fault(struct pt_regs *regs) +{ + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma; + unsigned int insn = 0; + int si_code, fault_code; + unsigned long address; + + fault_code = get_thread_fault_code(); + + if (notify_die(DIE_PAGE_FAULT, "page_fault", regs, + fault_code, 0, SIGSEGV) == NOTIFY_STOP) + return; + + si_code = SEGV_MAPERR; + address = current_thread_info()->fault_address; + + if ((fault_code & FAULT_CODE_ITLB) && + (fault_code & FAULT_CODE_DTLB)) + BUG(); + + if (regs->tstate & TSTATE_PRIV) { + unsigned long tpc = regs->tpc; + + /* Sanity check the PC. */ + if ((tpc >= KERNBASE && tpc < (unsigned long) _etext) || + (tpc >= MODULES_VADDR && tpc < MODULES_END)) { + /* Valid, no problems... */ + } else { + bad_kernel_pc(regs); + return; + } + } + + /* + * If we're in an interrupt or have no user + * context, we must not take the fault.. + */ + if (in_atomic() || !mm) + goto intr_or_no_mm; + + if (test_thread_flag(TIF_32BIT)) { + if (!(regs->tstate & TSTATE_PRIV)) + regs->tpc &= 0xffffffff; + address &= 0xffffffff; + } + + if (!down_read_trylock(&mm->mmap_sem)) { + if ((regs->tstate & TSTATE_PRIV) && + !search_exception_tables(regs->tpc)) { + insn = get_fault_insn(regs, insn); + goto handle_kernel_fault; + } + down_read(&mm->mmap_sem); + } + + vma = find_vma(mm, address); + if (!vma) + goto bad_area; + + /* Pure DTLB misses do not tell us whether the fault causing + * load/store/atomic was a write or not, it only says that there + * was no match. So in such a case we (carefully) read the + * instruction to try and figure this out. It's an optimization + * so it's ok if we can't do this. + * + * Special hack, window spill/fill knows the exact fault type. + */ + if (((fault_code & + (FAULT_CODE_DTLB | FAULT_CODE_WRITE | FAULT_CODE_WINFIXUP)) == FAULT_CODE_DTLB) && + (vma->vm_flags & VM_WRITE) != 0) { + insn = get_fault_insn(regs, 0); + if (!insn) + goto continue_fault; + if ((insn & 0xc0200000) == 0xc0200000 && + (insn & 0x1780000) != 0x1680000) { + /* Don't bother updating thread struct value, + * because update_mmu_cache only cares which tlb + * the access came from. + */ + fault_code |= FAULT_CODE_WRITE; + } + } +continue_fault: + + if (vma->vm_start <= address) + goto good_area; + if (!(vma->vm_flags & VM_GROWSDOWN)) + goto bad_area; + if (!(fault_code & FAULT_CODE_WRITE)) { + /* Non-faulting loads shouldn't expand stack. */ + insn = get_fault_insn(regs, insn); + if ((insn & 0xc0800000) == 0xc0800000) { + unsigned char asi; + + if (insn & 0x2000) + asi = (regs->tstate >> 24); + else + asi = (insn >> 5); + if ((asi & 0xf2) == 0x82) + goto bad_area; + } + } + if (expand_stack(vma, address)) + goto bad_area; + /* + * Ok, we have a good vm_area for this memory access, so + * we can handle it.. + */ +good_area: + si_code = SEGV_ACCERR; + + /* If we took a ITLB miss on a non-executable page, catch + * that here. + */ + if ((fault_code & FAULT_CODE_ITLB) && !(vma->vm_flags & VM_EXEC)) { + BUG_ON(address != regs->tpc); + BUG_ON(regs->tstate & TSTATE_PRIV); + goto bad_area; + } + + if (fault_code & FAULT_CODE_WRITE) { + if (!(vma->vm_flags & VM_WRITE)) + goto bad_area; + + /* Spitfire has an icache which does not snoop + * processor stores. Later processors do... + */ + if (tlb_type == spitfire && + (vma->vm_flags & VM_EXEC) != 0 && + vma->vm_file != NULL) + set_thread_fault_code(fault_code | + FAULT_CODE_BLKCOMMIT); + } else { + /* Allow reads even for write-only mappings */ + if (!(vma->vm_flags & (VM_READ | VM_EXEC))) + goto bad_area; + } + + switch (handle_mm_fault(mm, vma, address, (fault_code & FAULT_CODE_WRITE))) { + case VM_FAULT_MINOR: + current->min_flt++; + break; + case VM_FAULT_MAJOR: + current->maj_flt++; + break; + case VM_FAULT_SIGBUS: + goto do_sigbus; + case VM_FAULT_OOM: + goto out_of_memory; + default: + BUG(); + } + + up_read(&mm->mmap_sem); + goto fault_done; + + /* + * Something tried to access memory that isn't in our memory map.. + * Fix it, but check if it's kernel or user first.. + */ +bad_area: + insn = get_fault_insn(regs, insn); + up_read(&mm->mmap_sem); + +handle_kernel_fault: + do_kernel_fault(regs, si_code, fault_code, insn, address); + + goto fault_done; + +/* + * We ran out of memory, or some other thing happened to us that made + * us unable to handle the page fault gracefully. + */ +out_of_memory: + insn = get_fault_insn(regs, insn); + up_read(&mm->mmap_sem); + printk("VM: killing process %s\n", current->comm); + if (!(regs->tstate & TSTATE_PRIV)) + do_exit(SIGKILL); + goto handle_kernel_fault; + +intr_or_no_mm: + insn = get_fault_insn(regs, 0); + goto handle_kernel_fault; + +do_sigbus: + insn = get_fault_insn(regs, insn); + up_read(&mm->mmap_sem); + + /* + * Send a sigbus, regardless of whether we were in kernel + * or user mode. + */ + do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, insn, fault_code); + + /* Kernel mode? Handle exceptions or die */ + if (regs->tstate & TSTATE_PRIV) + goto handle_kernel_fault; + +fault_done: + /* These values are no longer needed, clear them. */ + set_thread_fault_code(0); + current_thread_info()->fault_address = 0; +} |