/* $Id: fault.c,v 1.54 2001/03/24 09:36:11 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 #define ELEMENTS(arr) (sizeof (arr)/sizeof (arr[0])) extern struct sparc_phys_banks sp_banks[SPARC_PHYS_BANKS]; /* 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; } 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 ? tsk->mm->context : 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)); die_if_kernel("Oops", regs); } static unsigned int get_user_insn(unsigned long tpc) { pgd_t *pgdp = pgd_offset(current->mm, tpc); pmd_t *pmdp; pte_t *ptep, pte; unsigned long pa; u32 insn = 0; if (pgd_none(*pgdp)) goto out; pmdp = pmd_offset(pgdp, tpc); if (pmd_none(*pmdp)) goto out; ptep = pte_offset(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: return insn; } static void do_fault_siginfo(int code, int sig, unsigned long address) { siginfo_t info; info.si_code = code; info.si_signo = sig; info.si_errno = 0; info.si_addr = (void *) address; 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 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) { if (regs->tstate & TSTATE_PRIV) { if (!regs->tpc || (regs->tpc & 0x3)) goto cannot_handle; insn = *(unsigned int *)regs->tpc; } else { insn = get_user_insn(regs->tpc); } } /* 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) && (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_exception_table (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, address); 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; si_code = SEGV_MAPERR; fault_code = current->thread.fault_code; address = current->thread.fault_address; if ((fault_code & FAULT_CODE_ITLB) && (fault_code & FAULT_CODE_DTLB)) BUG(); /* * If we're in an interrupt or have no user * context, we must not take the fault.. */ if (in_interrupt() || !mm) goto handle_kernel_fault; if ((current->thread.flags & SPARC_FLAG_32BIT) != 0) { regs->tpc &= 0xffffffff; address &= 0xffffffff; } 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) { unsigned long tpc = regs->tpc; if (tpc & 0x3) goto continue_fault; if (regs->tstate & TSTATE_PRIV) insn = *(unsigned int *)tpc; else insn = get_user_insn(tpc); 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 (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 (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) current->thread.use_blkcommit = 1; } 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 1: current->min_flt++; break; case 2: current->maj_flt++; break; case 0: goto do_sigbus; default: goto out_of_memory; } 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: 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: 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; do_sigbus: up_read(&mm->mmap_sem); /* * Send a sigbus, regardless of whether we were in kernel * or user mode. */ do_fault_siginfo(BUS_ADRERR, SIGBUS, address); /* 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. */ current->thread.fault_code = 0; current->thread.use_blkcommit = 0; current->thread.fault_address = 0; }