/* $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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define ELEMENTS(arr) (sizeof (arr)/sizeof (arr[0])) extern struct sparc_phys_banks sp_banks[SPARC_PHYS_BANKS]; /* * 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 __kprobes 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 __kprobes 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; }