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author | Steven Whitehouse <swhiteho@redhat.com> | 2006-03-31 15:34:58 -0500 |
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committer | Steven Whitehouse <swhiteho@redhat.com> | 2006-03-31 15:34:58 -0500 |
commit | 86579dd06deecfa6ac88d5e84e4d63c397cd6f6d (patch) | |
tree | b4475d3ccde53015ad84a06e4e55e64591171b75 /arch/i386/mm/fault.c | |
parent | 7ea9ea832212c4a755650f7c7cc1ff0b63292a41 (diff) | |
parent | a0f067802576d4eb4c65d40b8ee7d6ea3c81dd61 (diff) | |
download | linux-stable-86579dd06deecfa6ac88d5e84e4d63c397cd6f6d.tar.gz linux-stable-86579dd06deecfa6ac88d5e84e4d63c397cd6f6d.tar.bz2 linux-stable-86579dd06deecfa6ac88d5e84e4d63c397cd6f6d.zip |
Merge branch 'master'
Diffstat (limited to 'arch/i386/mm/fault.c')
-rw-r--r-- | arch/i386/mm/fault.c | 210 |
1 files changed, 138 insertions, 72 deletions
diff --git a/arch/i386/mm/fault.c b/arch/i386/mm/fault.c index cf572d9a3b6e..7f0fcf219a26 100644 --- a/arch/i386/mm/fault.c +++ b/arch/i386/mm/fault.c @@ -214,6 +214,68 @@ static noinline void force_sig_info_fault(int si_signo, int si_code, fastcall void do_invalid_op(struct pt_regs *, unsigned long); +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; + + /* + * set_pgd(pgd, *pgd_k); here would be useless on PAE + * and redundant with the set_pmd() on non-PAE. As would + * set_pud. + */ + + 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 + BUG_ON(pmd_page(*pmd) != pmd_page(*pmd_k)); + return pmd_k; +} + +/* + * Handle a fault on the vmalloc or module mapping area + * + * This assumes no large pages in there. + */ +static inline int vmalloc_fault(unsigned long address) +{ + unsigned long pgd_paddr; + pmd_t *pmd_k; + pte_t *pte_k; + /* + * 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_paddr = read_cr3(); + pmd_k = vmalloc_sync_one(__va(pgd_paddr), address); + if (!pmd_k) + return -1; + pte_k = pte_offset_kernel(pmd_k, address); + if (!pte_present(*pte_k)) + return -1; + return 0; +} + /* * This routine handles page faults. It determines the address, * and the problem, and then passes it off to one of the appropriate @@ -223,6 +285,8 @@ fastcall void do_invalid_op(struct pt_regs *, unsigned long); * bit 0 == 0 means no page found, 1 means protection fault * bit 1 == 0 means read, 1 means write * bit 2 == 0 means kernel, 1 means user-mode + * bit 3 == 1 means use of reserved bit detected + * bit 4 == 1 means fault was an instruction fetch */ fastcall void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code) @@ -237,13 +301,6 @@ fastcall void __kprobes do_page_fault(struct pt_regs *regs, /* get the address */ address = read_cr2(); - if (notify_die(DIE_PAGE_FAULT, "page fault", regs, error_code, 14, - SIGSEGV) == NOTIFY_STOP) - return; - /* It's safe to allow irq's after cr2 has been saved */ - if (regs->eflags & (X86_EFLAGS_IF|VM_MASK)) - local_irq_enable(); - tsk = current; si_code = SEGV_MAPERR; @@ -259,17 +316,29 @@ fastcall void __kprobes do_page_fault(struct pt_regs *regs, * * This verifies that the fault happens in kernel space * (error_code & 4) == 0, and that the fault was not a - * protection error (error_code & 1) == 0. + * protection error (error_code & 9) == 0. */ - if (unlikely(address >= TASK_SIZE)) { - if (!(error_code & 5)) - goto vmalloc_fault; - /* + if (unlikely(address >= TASK_SIZE)) { + if (!(error_code & 0x0000000d) && vmalloc_fault(address) >= 0) + return; + if (notify_die(DIE_PAGE_FAULT, "page fault", regs, error_code, 14, + SIGSEGV) == NOTIFY_STOP) + return; + /* * Don't take the mm semaphore here. If we fixup a prefetch * fault we could otherwise deadlock. */ goto bad_area_nosemaphore; - } + } + + if (notify_die(DIE_PAGE_FAULT, "page fault", regs, error_code, 14, + SIGSEGV) == NOTIFY_STOP) + return; + + /* It's safe to allow irq's after cr2 has been saved and the vmalloc + fault has been handled. */ + if (regs->eflags & (X86_EFLAGS_IF|VM_MASK)) + local_irq_enable(); mm = tsk->mm; @@ -440,24 +509,31 @@ no_context: bust_spinlocks(1); -#ifdef CONFIG_X86_PAE - if (error_code & 16) { - pte_t *pte = lookup_address(address); + if (oops_may_print()) { + #ifdef CONFIG_X86_PAE + if (error_code & 16) { + pte_t *pte = lookup_address(address); - if (pte && pte_present(*pte) && !pte_exec_kernel(*pte)) - printk(KERN_CRIT "kernel tried to execute NX-protected page - exploit attempt? (uid: %d)\n", current->uid); + if (pte && pte_present(*pte) && !pte_exec_kernel(*pte)) + printk(KERN_CRIT "kernel tried to execute " + "NX-protected page - exploit attempt? " + "(uid: %d)\n", current->uid); + } + #endif + if (address < PAGE_SIZE) + printk(KERN_ALERT "BUG: unable to handle kernel NULL " + "pointer dereference"); + else + printk(KERN_ALERT "BUG: unable to handle kernel paging" + " request"); + printk(" at virtual address %08lx\n",address); + printk(KERN_ALERT " printing eip:\n"); + printk("%08lx\n", regs->eip); } -#endif - if (address < PAGE_SIZE) - printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference"); - else - printk(KERN_ALERT "Unable to handle kernel paging request"); - printk(" at virtual address %08lx\n",address); - printk(KERN_ALERT " printing eip:\n"); - printk("%08lx\n", regs->eip); page = read_cr3(); page = ((unsigned long *) __va(page))[address >> 22]; - printk(KERN_ALERT "*pde = %08lx\n", page); + if (oops_may_print()) + printk(KERN_ALERT "*pde = %08lx\n", page); /* * We must not directly access the pte in the highpte * case, the page table might be allocated in highmem. @@ -465,7 +541,7 @@ no_context: * it's allocated already. */ #ifndef CONFIG_HIGHPTE - if (page & 1) { + if ((page & 1) && oops_may_print()) { page &= PAGE_MASK; address &= 0x003ff000; page = ((unsigned long *) __va(page))[address >> PAGE_SHIFT]; @@ -510,51 +586,41 @@ do_sigbus: tsk->thread.error_code = error_code; tsk->thread.trap_no = 14; force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk); - return; - -vmalloc_fault: - { - /* - * 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 index = pgd_index(address); - unsigned long pgd_paddr; - pgd_t *pgd, *pgd_k; - pud_t *pud, *pud_k; - pmd_t *pmd, *pmd_k; - pte_t *pte_k; - - pgd_paddr = read_cr3(); - pgd = index + (pgd_t *)__va(pgd_paddr); - pgd_k = init_mm.pgd + index; - - if (!pgd_present(*pgd_k)) - goto no_context; - - /* - * set_pgd(pgd, *pgd_k); here would be useless on PAE - * and redundant with the set_pmd() on non-PAE. As would - * set_pud. - */ +} - pud = pud_offset(pgd, address); - pud_k = pud_offset(pgd_k, address); - if (!pud_present(*pud_k)) - goto no_context; - - pmd = pmd_offset(pud, address); - pmd_k = pmd_offset(pud_k, address); - if (!pmd_present(*pmd_k)) - goto no_context; - set_pmd(pmd, *pmd_k); +#ifndef CONFIG_X86_PAE +void vmalloc_sync_all(void) +{ + /* + * Note that races in the updates of insync and start aren't + * problematic: insync can only get set bits added, and updates to + * start are only improving performance (without affecting correctness + * if undone). + */ + static DECLARE_BITMAP(insync, PTRS_PER_PGD); + static unsigned long start = TASK_SIZE; + unsigned long address; - pte_k = pte_offset_kernel(pmd_k, address); - if (!pte_present(*pte_k)) - goto no_context; - return; + BUILD_BUG_ON(TASK_SIZE & ~PGDIR_MASK); + for (address = start; address >= TASK_SIZE; address += PGDIR_SIZE) { + if (!test_bit(pgd_index(address), insync)) { + unsigned long flags; + struct page *page; + + spin_lock_irqsave(&pgd_lock, flags); + for (page = pgd_list; page; page = + (struct page *)page->index) + if (!vmalloc_sync_one(page_address(page), + address)) { + BUG_ON(page != pgd_list); + break; + } + spin_unlock_irqrestore(&pgd_lock, flags); + if (!page) + set_bit(pgd_index(address), insync); + } + if (address == start && test_bit(pgd_index(address), insync)) + start = address + PGDIR_SIZE; } } +#endif |