extern void die(const char *,struct pt_regs *,long);
-#ifdef CONFIG_KPROBES
-ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain);
-int register_page_fault_notifier(struct notifier_block *nb)
-{
- vmalloc_sync_all();
- return atomic_notifier_chain_register(¬ify_page_fault_chain, nb);
-}
-
-int unregister_page_fault_notifier(struct notifier_block *nb)
-{
- return atomic_notifier_chain_unregister(¬ify_page_fault_chain, nb);
-}
-
-static inline int notify_page_fault(enum die_val val, const char *str,
- struct pt_regs *regs, long err, int trap, int sig)
-{
- struct die_args args = {
- .regs = regs,
- .str = str,
- .err = err,
- .trapnr = trap,
- .signr = sig
- };
- return atomic_notifier_call_chain(¬ify_page_fault_chain, val, &args);
-}
-#else
-static inline int notify_page_fault(enum die_val val, const char *str,
- struct pt_regs *regs, long err, int trap, int sig)
-{
- return NOTIFY_DONE;
-}
-#endif
-
-
/*
* Unlock any spinlocks which will prevent us from getting the
* message out
unsigned seg = regs->xcs & 0xffff;
u32 seg_ar, seg_limit, base, *desc;
- /* Unlikely, but must come before segment checks. */
- if (unlikely(regs->eflags & VM_MASK)) {
- base = seg << 4;
- *eip_limit = base + 0xffff;
- return base + (eip & 0xffff);
- }
-
/* The standard kernel/user address space limit. */
*eip_limit = (seg & 3) ? USER_DS.seg : KERNEL_DS.seg;
+
+ /* Unlikely, but must come before segment checks. */
+ if (unlikely((regs->eflags & VM_MASK) != 0))
+ return eip + (seg << 4);
/* By far the most common cases. */
if (likely(seg == __USER_CS || seg == __KERNEL_CS))
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
* 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)
/* 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;
*
* This verifies that the fault happens in kernel space
* (error_code & 4) == 0, and that the fault was not a
- * protection error (error_code & 9) == 0.
+ * protection error (error_code & 1) == 0.
*/
- if (unlikely(address >= TASK_SIZE)) {
- if (!(error_code & 0x0000000d) && vmalloc_fault(address) >= 0)
- return;
- if (notify_page_fault(DIE_PAGE_FAULT, "page fault", regs, error_code, 14,
- SIGSEGV) == NOTIFY_STOP)
- return;
- /*
+ if (unlikely(address >= TASK_SIZE)) {
+ if (!(error_code & 5))
+ goto vmalloc_fault;
+ /*
* Don't take the mm semaphore here. If we fixup a prefetch
* fault we could otherwise deadlock.
*/
goto bad_area_nosemaphore;
- }
-
- if (notify_page_fault(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;
/* When running in the kernel we expect faults to occur only to
* addresses in user space. All other faults represent errors in the
* kernel and should generate an OOPS. Unfortunatly, in the case of an
- * erroneous fault occurring in a code path which already holds mmap_sem
+ * erroneous fault occuring in a code path which already holds mmap_sem
* we will deadlock attempting to validate the fault against the
* address space. Luckily the kernel only validly references user
* space from well defined areas of code, which are listed in the
goto bad_area;
if (error_code & 4) {
/*
- * Accessing the stack below %esp is always a bug.
- * The large cushion allows instructions like enter
- * and pusha to work. ("enter $65535,$31" pushes
- * 32 pointers and then decrements %esp by 65535.)
+ * accessing the stack below %esp is always a bug.
+ * The "+ 32" is there due to some instructions (like
+ * pusha) doing post-decrement on the stack and that
+ * doesn't show up until later..
*/
- if (address + 65536 + 32 * sizeof(unsigned long) < regs->esp)
+ if (address + 32 < regs->esp)
goto bad_area;
}
if (expand_stack(vma, address))
bust_spinlocks(1);
- if (oops_may_print()) {
- #ifdef CONFIG_X86_PAE
- if (error_code & 16) {
- pte_t *pte = lookup_address(address);
+#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);
- }
- #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);
+ 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 "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];
- if (oops_may_print())
- printk(KERN_ALERT "*pde = %08lx\n", page);
+ 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.
* it's allocated already.
*/
#ifndef CONFIG_HIGHPTE
- if ((page & 1) && oops_may_print()) {
+ if (page & 1) {
page &= PAGE_MASK;
address &= 0x003ff000;
page = ((unsigned long *) __va(page))[address >> PAGE_SHIFT];
tsk->thread.error_code = error_code;
tsk->thread.trap_no = 14;
force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk);
-}
+ return;
-#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;
+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;
- 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;
+ 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);
+
+ pte_k = pte_offset_kernel(pmd_k, address);
+ if (!pte_present(*pte_k))
+ goto no_context;
+ return;
}
}
-#endif
git://git.onelab.eu / linux-2.6.git / blobdiff