diff options
Diffstat (limited to 'arch/ppc/mm/fault.c')
| -rw-r--r-- | arch/ppc/mm/fault.c | 93 |
1 files changed, 73 insertions, 20 deletions
diff --git a/arch/ppc/mm/fault.c b/arch/ppc/mm/fault.c index 076ee56e5..7a899252f 100644 --- a/arch/ppc/mm/fault.c +++ b/arch/ppc/mm/fault.c @@ -62,10 +62,21 @@ void do_page_fault(struct pt_regs *regs, unsigned long address, { struct vm_area_struct * vma; struct mm_struct *mm = current->mm; + siginfo_t info; + int code = SEGV_MAPERR; #if defined(CONFIG_4xx) int is_write = error_code & ESR_DST; #else int is_write = error_code & 0x02000000; + + /* + * Fortunately the bit assignments in SRR1 for an instruction + * fault and DSISR for a data fault are mostly the same for the + * bits we are interested in. But there are some bits which + * indicate errors in DSISR but can validly be set in SRR1. + */ + if (regs->trap == 0x400) + error_code &= 0x48200000; #endif /* CONFIG_4xx */ #if defined(CONFIG_XMON) || defined(CONFIG_KGDB) @@ -82,16 +93,7 @@ void do_page_fault(struct pt_regs *regs, unsigned long address, #endif /* !CONFIG_4xx */ #endif /* CONFIG_XMON || CONFIG_KGDB */ - if (in_interrupt()) { - static int complained; - if (complained < 20) { - ++complained; - printk("page fault in interrupt handler, addr=%lx\n", - address); - show_regs(regs); - } - } - if (current == NULL || mm == NULL) { + if (in_interrupt() || mm == NULL) { bad_page_fault(regs, address); return; } @@ -107,10 +109,12 @@ void do_page_fault(struct pt_regs *regs, unsigned long address, goto bad_area; good_area: + code = SEGV_ACCERR; #if defined(CONFIG_6xx) if (error_code & 0x95700000) /* an error such as lwarx to I/O controller space, address matching DABR, eciwx, etc. */ + goto bad_area; #endif /* CONFIG_6xx */ #if defined(CONFIG_8xx) /* The MPC8xx seems to always set 0x80000000, which is @@ -119,9 +123,8 @@ good_area: */ if (error_code & 0x10000000) /* Guarded storage error. */ -#endif /* CONFIG_8xx */ goto bad_area; - +#endif /* CONFIG_8xx */ /* a write */ if (is_write) { @@ -135,8 +138,25 @@ good_area: if (!(vma->vm_flags & (VM_READ | VM_EXEC))) goto bad_area; } - if (!handle_mm_fault(mm, vma, address, is_write)) - 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, is_write)) { + case 1: + current->min_flt++; + break; + case 2: + current->maj_flt++; + break; + case 0: + goto do_sigbus; + default: + goto out_of_memory; + } + up(&mm->mmap_sem); /* * keep track of tlb+htab misses that are good addrs but @@ -147,22 +167,55 @@ good_area: return; bad_area: - up(&mm->mmap_sem); pte_errors++; + + /* User mode accesses cause a SIGSEGV */ + if (user_mode(regs)) { + info.si_signo = SIGSEGV; + info.si_errno = 0; + info.si_code = code; + info.si_addr = (void *) address; + force_sig_info(SIGSEGV, &info, current); + return; + } + + bad_page_fault(regs, address); + return; + +/* + * 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(&mm->mmap_sem); + printk("VM: killing process %s\n", current->comm); + if (user_mode(regs)) + do_exit(SIGKILL); bad_page_fault(regs, address); + return; + +do_sigbus: + up(&mm->mmap_sem); + info.si_signo = SIGBUS; + info.si_errno = 0; + info.si_code = BUS_ADRERR; + info.si_addr = (void *)address; + force_sig_info (SIGBUS, &info, current); + if (!user_mode(regs)) + bad_page_fault(regs, address); } +/* + * bad_page_fault is called when we have a bad access from the kernel. + * It is called from do_page_fault above and from some of the procedures + * in traps.c. + */ void bad_page_fault(struct pt_regs *regs, unsigned long address) { unsigned long fixup; - if (user_mode(regs)) { - force_sig(SIGSEGV, current); - return; - } - /* Are we prepared to handle this fault? */ if ((fixup = search_exception_table(regs->nip)) != 0) { regs->nip = fixup; |