diff options
Diffstat (limited to 'arch/sh/mm/fault_32.c')
| -rw-r--r-- | arch/sh/mm/fault_32.c | 164 |
1 files changed, 105 insertions, 59 deletions
diff --git a/arch/sh/mm/fault_32.c b/arch/sh/mm/fault_32.c index 71925946f1e1..dbbdeba2cee5 100644 --- a/arch/sh/mm/fault_32.c +++ b/arch/sh/mm/fault_32.c @@ -2,7 +2,7 @@ * Page fault handler for SH with an MMU. * * Copyright (C) 1999 Niibe Yutaka - * Copyright (C) 2003 - 2008 Paul Mundt + * Copyright (C) 2003 - 2009 Paul Mundt * * Based on linux/arch/i386/mm/fault.c: * Copyright (C) 1995 Linus Torvalds @@ -25,18 +25,91 @@ static inline int notify_page_fault(struct pt_regs *regs, int trap) { int ret = 0; -#ifdef CONFIG_KPROBES - if (!user_mode(regs)) { + if (kprobes_built_in() && !user_mode(regs)) { preempt_disable(); if (kprobe_running() && kprobe_fault_handler(regs, trap)) ret = 1; preempt_enable(); } -#endif return ret; } +static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address) +{ + unsigned index = pgd_index(address); + pgd_t *pgd_k; + pud_t *pud, *pud_k; + pmd_t *pmd, *pmd_k; + + pgd += index; + pgd_k = init_mm.pgd + index; + + if (!pgd_present(*pgd_k)) + return NULL; + + pud = pud_offset(pgd, address); + pud_k = pud_offset(pgd_k, address); + if (!pud_present(*pud_k)) + return NULL; + + pmd = pmd_offset(pud, address); + pmd_k = pmd_offset(pud_k, address); + if (!pmd_present(*pmd_k)) + return NULL; + + if (!pmd_present(*pmd)) + set_pmd(pmd, *pmd_k); + else { + /* + * The page tables are fully synchronised so there must + * be another reason for the fault. Return NULL here to + * signal that we have not taken care of the fault. + */ + BUG_ON(pmd_page(*pmd) != pmd_page(*pmd_k)); + return NULL; + } + + return pmd_k; +} + +/* + * Handle a fault on the vmalloc or module mapping area + */ +static noinline int vmalloc_fault(unsigned long address) +{ + pgd_t *pgd_k; + pmd_t *pmd_k; + pte_t *pte_k; + + /* Make sure we are in vmalloc area: */ + if (!(address >= VMALLOC_START && address < VMALLOC_END)) + return -1; + + /* + * Synchronize this task's top level page-table + * with the 'reference' page table. + * + * Do _not_ use "current" here. We might be inside + * an interrupt in the middle of a task switch.. + */ + pgd_k = get_TTB(); + pmd_k = vmalloc_sync_one(pgd_k, address); + if (!pmd_k) + return -1; + + pte_k = pte_offset_kernel(pmd_k, address); + if (!pte_present(*pte_k)) + return -1; + + return 0; +} + +static int fault_in_kernel_space(unsigned long address) +{ + return address >= TASK_SIZE; +} + /* * This routine handles page faults. It determines the address, * and the problem, and then passes it off to one of the appropriate @@ -46,6 +119,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, unsigned long writeaccess, unsigned long address) { + unsigned long vec; struct task_struct *tsk; struct mm_struct *mm; struct vm_area_struct * vma; @@ -53,59 +127,30 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, int fault; siginfo_t info; - /* - * We don't bother with any notifier callbacks here, as they are - * all handled through the __do_page_fault() fast-path. - */ - tsk = current; + mm = tsk->mm; si_code = SEGV_MAPERR; + vec = lookup_exception_vector(); - if (unlikely(address >= TASK_SIZE)) { - /* - * Synchronize this task's top level page-table - * with the 'reference' page table. - * - * Do _not_ use "tsk" here. We might be inside - * an interrupt in the middle of a task switch.. - */ - int offset = pgd_index(address); - pgd_t *pgd, *pgd_k; - pud_t *pud, *pud_k; - pmd_t *pmd, *pmd_k; - - pgd = get_TTB() + offset; - pgd_k = swapper_pg_dir + offset; - - if (!pgd_present(*pgd)) { - if (!pgd_present(*pgd_k)) - goto bad_area_nosemaphore; - set_pgd(pgd, *pgd_k); + /* + * 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 (unlikely(fault_in_kernel_space(address))) { + if (vmalloc_fault(address) >= 0) return; - } - - pud = pud_offset(pgd, address); - pud_k = pud_offset(pgd_k, address); - - if (!pud_present(*pud)) { - if (!pud_present(*pud_k)) - goto bad_area_nosemaphore; - set_pud(pud, *pud_k); + if (notify_page_fault(regs, vec)) return; - } - pmd = pmd_offset(pud, address); - pmd_k = pmd_offset(pud_k, address); - if (pmd_present(*pmd) || !pmd_present(*pmd_k)) - goto bad_area_nosemaphore; - set_pmd(pmd, *pmd_k); - - return; + goto bad_area_nosemaphore; } - mm = tsk->mm; - - if (unlikely(notify_page_fault(regs, lookup_exception_vector()))) + if (unlikely(notify_page_fault(regs, vec))) return; /* Only enable interrupts if they were on before the fault */ @@ -115,8 +160,8 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, perf_swcounter_event(PERF_COUNT_SW_PAGE_FAULTS, 1, 0, regs, address); /* - * If we're in an interrupt or have no user - * context, we must not take the fault.. + * If we're in an interrupt, have no user context or are running + * in an atomic region then we must not take the fault: */ if (in_atomic() || !mm) goto no_context; @@ -132,10 +177,11 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, 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.. - */ + + /* + * Ok, we have a good vm_area for this memory access, so + * we can handle it.. + */ good_area: si_code = SEGV_ACCERR; if (writeaccess) { @@ -173,10 +219,10 @@ survive: 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.. - */ + /* + * 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); |