diff options
Diffstat (limited to 'arch/sparc/mm/fault.c')
| -rw-r--r-- | arch/sparc/mm/fault.c | 596 |
1 files changed, 596 insertions, 0 deletions
diff --git a/arch/sparc/mm/fault.c b/arch/sparc/mm/fault.c new file mode 100644 index 0000000..37f4107 --- /dev/null +++ b/arch/sparc/mm/fault.c @@ -0,0 +1,596 @@ +/* $Id: fault.c,v 1.122 2001/11/17 07:19:26 davem Exp $ + * fault.c: Page fault handlers for the Sparc. + * + * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu) + * Copyright (C) 1996 Eddie C. Dost (ecd@skynet.be) + * Copyright (C) 1997 Jakub Jelinek (jj@sunsite.mff.cuni.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/threads.h> +#include <linux/kernel.h> +#include <linux/signal.h> +#include <linux/mm.h> +#include <linux/smp.h> +#include <linux/smp_lock.h> +#include <linux/interrupt.h> +#include <linux/module.h> + +#include <asm/system.h> +#include <asm/segment.h> +#include <asm/page.h> +#include <asm/pgtable.h> +#include <asm/memreg.h> +#include <asm/openprom.h> +#include <asm/oplib.h> +#include <asm/smp.h> +#include <asm/traps.h> +#include <asm/kdebug.h> +#include <asm/uaccess.h> + +#define ELEMENTS(arr) (sizeof (arr)/sizeof (arr[0])) + +extern int prom_node_root; + +/* At boot time we determine these two values necessary for setting + * up the segment maps and page table entries (pte's). + */ + +int num_segmaps, num_contexts; +int invalid_segment; + +/* various Virtual Address Cache parameters we find at boot time... */ + +int vac_size, vac_linesize, vac_do_hw_vac_flushes; +int vac_entries_per_context, vac_entries_per_segment; +int vac_entries_per_page; + +/* Nice, simple, prom library does all the sweating for us. ;) */ +int prom_probe_memory (void) +{ + register struct linux_mlist_v0 *mlist; + register unsigned long bytes, base_paddr, tally; + register int i; + + i = 0; + mlist= *prom_meminfo()->v0_available; + bytes = tally = mlist->num_bytes; + base_paddr = (unsigned long) 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 = (unsigned long) mlist->start_adr; + sp_banks[i].num_bytes = mlist->num_bytes; + } + + i++; + sp_banks[i].base_addr = 0xdeadbeef; + 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; +} + +/* Traverse the memory lists in the prom to see how much physical we + * have. + */ +unsigned long +probe_memory(void) +{ + int total; + + total = prom_probe_memory(); + + /* Oh man, much nicer, keep the dirt in promlib. */ + return total; +} + +extern void sun4c_complete_all_stores(void); + +/* Whee, a level 15 NMI interrupt memory error. Let's have fun... */ +asmlinkage void sparc_lvl15_nmi(struct pt_regs *regs, unsigned long serr, + unsigned long svaddr, unsigned long aerr, + unsigned long avaddr) +{ + sun4c_complete_all_stores(); + printk("FAULT: NMI received\n"); + printk("SREGS: Synchronous Error %08lx\n", serr); + printk(" Synchronous Vaddr %08lx\n", svaddr); + printk(" Asynchronous Error %08lx\n", aerr); + printk(" Asynchronous Vaddr %08lx\n", avaddr); + if (sun4c_memerr_reg) + printk(" Memory Parity Error %08lx\n", *sun4c_memerr_reg); + printk("REGISTER DUMP:\n"); + show_regs(regs); + prom_halt(); +} + +static void unhandled_fault(unsigned long, struct task_struct *, + struct pt_regs *) __attribute__ ((noreturn)); + +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 %08lx\n", address); + } + printk(KERN_ALERT "tsk->{mm,active_mm}->context = %08lx\n", + (tsk->mm ? tsk->mm->context : tsk->active_mm->context)); + printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %08lx\n", + (tsk->mm ? (unsigned long) tsk->mm->pgd : + (unsigned long) tsk->active_mm->pgd)); + die_if_kernel("Oops", regs); +} + +asmlinkage int lookup_fault(unsigned long pc, unsigned long ret_pc, + unsigned long address) +{ + struct pt_regs regs; + unsigned long g2; + unsigned int insn; + int i; + + i = search_extables_range(ret_pc, &g2); + switch (i) { + case 3: + /* load & store will be handled by fixup */ + return 3; + + case 1: + /* store will be handled by fixup, load will bump out */ + /* for _to_ macros */ + insn = *((unsigned int *) pc); + if ((insn >> 21) & 1) + return 1; + break; + + case 2: + /* load will be handled by fixup, store will bump out */ + /* for _from_ macros */ + insn = *((unsigned int *) pc); + if (!((insn >> 21) & 1) || ((insn>>19)&0x3f) == 15) + return 2; + break; + + default: + break; + }; + + memset(®s, 0, sizeof (regs)); + regs.pc = pc; + regs.npc = pc + 4; + __asm__ __volatile__( + "rd %%psr, %0\n\t" + "nop\n\t" + "nop\n\t" + "nop\n" : "=r" (regs.psr)); + unhandled_fault(address, current, ®s); + + /* Not reached */ + return 0; +} + +extern unsigned long safe_compute_effective_address(struct pt_regs *, + unsigned int); + +static unsigned long compute_si_addr(struct pt_regs *regs, int text_fault) +{ + unsigned int insn; + + if (text_fault) + return regs->pc; + + if (regs->psr & PSR_PS) { + insn = *(unsigned int *) regs->pc; + } else { + __get_user(insn, (unsigned int *) regs->pc); + } + + return safe_compute_effective_address(regs, insn); +} + +asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write, + unsigned long address) +{ + struct vm_area_struct *vma; + struct task_struct *tsk = current; + struct mm_struct *mm = tsk->mm; + unsigned int fixup; + unsigned long g2; + siginfo_t info; + int from_user = !(regs->psr & PSR_PS); + + if(text_fault) + address = regs->pc; + + /* + * We fault-in kernel-space virtual memory on-demand. The + * 'reference' page table is init_mm.pgd. + * + * NOTE! We MUST NOT take any locks for this case. We may + * be in an interrupt or a critical region, and should + * only copy the information from the master page table, + * nothing more. + */ + if (!ARCH_SUN4C_SUN4 && address >= TASK_SIZE) + goto vmalloc_fault; + + info.si_code = SEGV_MAPERR; + + /* + * If we're in an interrupt or have no user + * context, we must not take the fault.. + */ + if (in_atomic() || !mm) + goto no_context; + + down_read(&mm->mmap_sem); + + /* + * The kernel referencing a bad kernel pointer can lock up + * a sun4c machine completely, so we must attempt recovery. + */ + if(!from_user && address >= PAGE_OFFSET) + goto bad_area; + + vma = find_vma(mm, address); + if(!vma) + goto bad_area; + 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: + info.si_code = SEGV_ACCERR; + if(write) { + if(!(vma->vm_flags & VM_WRITE)) + goto bad_area; + } else { + /* Allow reads even for write-only mappings */ + if(!(vma->vm_flags & (VM_READ | VM_EXEC))) + goto bad_area; + } + + /* + * If for any reason at all we couldn't handle the fault, + * make sure we exit gracefully rather than endlessly redo + * the fault. + */ + switch (handle_mm_fault(mm, vma, address, write)) { + case VM_FAULT_SIGBUS: + goto do_sigbus; + case VM_FAULT_OOM: + goto out_of_memory; + case VM_FAULT_MAJOR: + current->maj_flt++; + break; + case VM_FAULT_MINOR: + default: + current->min_flt++; + break; + } + up_read(&mm->mmap_sem); + return; + + /* + * 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); + +bad_area_nosemaphore: + /* User mode accesses just cause a SIGSEGV */ + if(from_user) { +#if 0 + printk("Fault whee %s [%d]: segfaults at %08lx pc=%08lx\n", + tsk->comm, tsk->pid, address, regs->pc); +#endif + info.si_signo = SIGSEGV; + info.si_errno = 0; + /* info.si_code set above to make clear whether + this was a SEGV_MAPERR or SEGV_ACCERR fault. */ + info.si_addr = (void __user *)compute_si_addr(regs, text_fault); + info.si_trapno = 0; + force_sig_info (SIGSEGV, &info, tsk); + return; + } + + /* Is this in ex_table? */ +no_context: + g2 = regs->u_regs[UREG_G2]; + if (!from_user && (fixup = search_extables_range(regs->pc, &g2))) { + if (fixup > 10) { /* Values below are reserved for other things */ + extern const unsigned __memset_start[]; + extern const unsigned __memset_end[]; + extern const unsigned __csum_partial_copy_start[]; + extern const unsigned __csum_partial_copy_end[]; + +#ifdef DEBUG_EXCEPTIONS + printk("Exception: PC<%08lx> faddr<%08lx>\n", regs->pc, address); + printk("EX_TABLE: insn<%08lx> fixup<%08x> g2<%08lx>\n", + regs->pc, fixup, g2); +#endif + if ((regs->pc >= (unsigned long)__memset_start && + regs->pc < (unsigned long)__memset_end) || + (regs->pc >= (unsigned long)__csum_partial_copy_start && + regs->pc < (unsigned long)__csum_partial_copy_end)) { + regs->u_regs[UREG_I4] = address; + regs->u_regs[UREG_I5] = regs->pc; + } + regs->u_regs[UREG_G2] = g2; + regs->pc = fixup; + regs->npc = regs->pc + 4; + return; + } + } + + unhandled_fault (address, tsk, regs); + do_exit(SIGKILL); + +/* + * 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", tsk->comm); + if (from_user) + do_exit(SIGKILL); + goto no_context; + +do_sigbus: + up_read(&mm->mmap_sem); + info.si_signo = SIGBUS; + info.si_errno = 0; + info.si_code = BUS_ADRERR; + info.si_addr = (void __user *) compute_si_addr(regs, text_fault); + info.si_trapno = 0; + force_sig_info (SIGBUS, &info, tsk); + if (!from_user) + goto no_context; + +vmalloc_fault: + { + /* + * Synchronize this task's top level page-table + * with the 'reference' page table. + */ + int offset = pgd_index(address); + pgd_t *pgd, *pgd_k; + pmd_t *pmd, *pmd_k; + + pgd = tsk->active_mm->pgd + offset; + pgd_k = init_mm.pgd + offset; + + if (!pgd_present(*pgd)) { + if (!pgd_present(*pgd_k)) + goto bad_area_nosemaphore; + pgd_val(*pgd) = pgd_val(*pgd_k); + return; + } + + pmd = pmd_offset(pgd, address); + pmd_k = pmd_offset(pgd_k, address); + + if (pmd_present(*pmd) || !pmd_present(*pmd_k)) + goto bad_area_nosemaphore; + *pmd = *pmd_k; + return; + } +} + +asmlinkage void do_sun4c_fault(struct pt_regs *regs, int text_fault, int write, + unsigned long address) +{ + extern void sun4c_update_mmu_cache(struct vm_area_struct *, + unsigned long,pte_t); + extern pte_t *sun4c_pte_offset_kernel(pmd_t *,unsigned long); + struct task_struct *tsk = current; + struct mm_struct *mm = tsk->mm; + pgd_t *pgdp; + pte_t *ptep; + + if (text_fault) { + address = regs->pc; + } else if (!write && + !(regs->psr & PSR_PS)) { + unsigned int insn, __user *ip; + + ip = (unsigned int __user *)regs->pc; + if (!get_user(insn, ip)) { + if ((insn & 0xc1680000) == 0xc0680000) + write = 1; + } + } + + if (!mm) { + /* We are oopsing. */ + do_sparc_fault(regs, text_fault, write, address); + BUG(); /* P3 Oops already, you bitch */ + } + + pgdp = pgd_offset(mm, address); + ptep = sun4c_pte_offset_kernel((pmd_t *) pgdp, address); + + if (pgd_val(*pgdp)) { + if (write) { + if ((pte_val(*ptep) & (_SUN4C_PAGE_WRITE|_SUN4C_PAGE_PRESENT)) + == (_SUN4C_PAGE_WRITE|_SUN4C_PAGE_PRESENT)) { + unsigned long flags; + + *ptep = __pte(pte_val(*ptep) | _SUN4C_PAGE_ACCESSED | + _SUN4C_PAGE_MODIFIED | + _SUN4C_PAGE_VALID | + _SUN4C_PAGE_DIRTY); + + local_irq_save(flags); + if (sun4c_get_segmap(address) != invalid_segment) { + sun4c_put_pte(address, pte_val(*ptep)); + local_irq_restore(flags); + return; + } + local_irq_restore(flags); + } + } else { + if ((pte_val(*ptep) & (_SUN4C_PAGE_READ|_SUN4C_PAGE_PRESENT)) + == (_SUN4C_PAGE_READ|_SUN4C_PAGE_PRESENT)) { + unsigned long flags; + + *ptep = __pte(pte_val(*ptep) | _SUN4C_PAGE_ACCESSED | + _SUN4C_PAGE_VALID); + + local_irq_save(flags); + if (sun4c_get_segmap(address) != invalid_segment) { + sun4c_put_pte(address, pte_val(*ptep)); + local_irq_restore(flags); + return; + } + local_irq_restore(flags); + } + } + } + + /* This conditional is 'interesting'. */ + if (pgd_val(*pgdp) && !(write && !(pte_val(*ptep) & _SUN4C_PAGE_WRITE)) + && (pte_val(*ptep) & _SUN4C_PAGE_VALID)) + /* Note: It is safe to not grab the MMAP semaphore here because + * we know that update_mmu_cache() will not sleep for + * any reason (at least not in the current implementation) + * and therefore there is no danger of another thread getting + * on the CPU and doing a shrink_mmap() on this vma. + */ + sun4c_update_mmu_cache (find_vma(current->mm, address), address, + *ptep); + else + do_sparc_fault(regs, text_fault, write, address); +} + +/* This always deals with user addresses. */ +inline void force_user_fault(unsigned long address, int write) +{ + struct vm_area_struct *vma; + struct task_struct *tsk = current; + struct mm_struct *mm = tsk->mm; + siginfo_t info; + + info.si_code = SEGV_MAPERR; + +#if 0 + printk("wf<pid=%d,wr=%d,addr=%08lx>\n", + tsk->pid, write, address); +#endif + down_read(&mm->mmap_sem); + vma = find_vma(mm, address); + if(!vma) + goto bad_area; + 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; +good_area: + info.si_code = SEGV_ACCERR; + if(write) { + if(!(vma->vm_flags & VM_WRITE)) + goto bad_area; + } else { + if(!(vma->vm_flags & (VM_READ | VM_EXEC))) + goto bad_area; + } + switch (handle_mm_fault(mm, vma, address, write)) { + case VM_FAULT_SIGBUS: + case VM_FAULT_OOM: + goto do_sigbus; + } + up_read(&mm->mmap_sem); + return; +bad_area: + up_read(&mm->mmap_sem); +#if 0 + printk("Window whee %s [%d]: segfaults at %08lx\n", + tsk->comm, tsk->pid, address); +#endif + info.si_signo = SIGSEGV; + info.si_errno = 0; + /* info.si_code set above to make clear whether + this was a SEGV_MAPERR or SEGV_ACCERR fault. */ + info.si_addr = (void __user *) address; + info.si_trapno = 0; + force_sig_info (SIGSEGV, &info, tsk); + return; + +do_sigbus: + up_read(&mm->mmap_sem); + info.si_signo = SIGBUS; + info.si_errno = 0; + info.si_code = BUS_ADRERR; + info.si_addr = (void __user *) address; + info.si_trapno = 0; + force_sig_info (SIGBUS, &info, tsk); +} + +void window_overflow_fault(void) +{ + unsigned long sp; + + sp = current_thread_info()->rwbuf_stkptrs[0]; + if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK)) + force_user_fault(sp + 0x38, 1); + force_user_fault(sp, 1); +} + +void window_underflow_fault(unsigned long sp) +{ + if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK)) + force_user_fault(sp + 0x38, 0); + force_user_fault(sp, 0); +} + +void window_ret_fault(struct pt_regs *regs) +{ + unsigned long sp; + + sp = regs->u_regs[UREG_FP]; + if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK)) + force_user_fault(sp + 0x38, 0); + force_user_fault(sp, 0); +} |