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