4 files changed, 123 insertions, 57 deletions

diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c
index f20797b8da1d..d510de7e4f2a 100644
--- a/arch/i386/kernel/traps.c
+++ b/arch/i386/kernel/traps.c
@@ -99,6 +99,8 @@ int register_die_notifier(struct notifier_block *nb)
 {
         int err = 0;
         unsigned long flags;
+
+        vmalloc_sync_all();
         spin_lock_irqsave(&die_notifier_lock, flags);
         err = notifier_chain_register(&i386die_chain, nb);
         spin_unlock_irqrestore(&die_notifier_lock, flags);
@@ -713,6 +715,7 @@ fastcall void do_nmi(struct pt_regs * regs, long error_code)
 
 void set_nmi_callback(nmi_callback_t callback)
 {
+        vmalloc_sync_all();
         rcu_assign_pointer(nmi_callback, callback);
 }
 EXPORT_SYMBOL_GPL(set_nmi_callback);
diff --git a/arch/i386/mm/fault.c b/arch/i386/mm/fault.c
index cf572d9a3b6e..bbb24af5d860 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;
 
@@ -510,51 +579,41 @@ 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
diff --git a/include/asm-i386/pgtable-2level.h b/include/asm-i386/pgtable-2level.h
index 74ef721b534d..27bde973abc7 100644
--- a/include/asm-i386/pgtable-2level.h
+++ b/include/asm-i386/pgtable-2level.h
@@ -61,4 +61,6 @@ static inline int pte_exec_kernel(pte_t pte)
 #define __pte_to_swp_entry(pte)         ((swp_entry_t) { (pte).pte_low })
 #define __swp_entry_to_pte(x)           ((pte_t) { (x).val })
 
+void vmalloc_sync_all(void);
+
 #endif /* _I386_PGTABLE_2LEVEL_H */
diff --git a/include/asm-i386/pgtable-3level.h b/include/asm-i386/pgtable-3level.h
index f1a8b454920a..36a5aa63cbbf 100644
--- a/include/asm-i386/pgtable-3level.h
+++ b/include/asm-i386/pgtable-3level.h
@@ -152,4 +152,6 @@ static inline pmd_t pfn_pmd(unsigned long page_nr, pgprot_t pgprot)
 
 #define __pmd_free_tlb(tlb, x)          do { } while (0)
 
+#define vmalloc_sync_all() ((void)0)
+
 #endif /* _I386_PGTABLE_3LEVEL_H */