Merge branch 'x86-xen-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-2.6.git] / arch / x86 / mm / fault.c
index 3fff490..5ec7ae3 100644 (file)
@@ -1,65 +1,55 @@
 /*
  *  Copyright (C) 1995  Linus Torvalds
- *  Copyright (C) 2001,2002 Andi Kleen, SuSE Labs.
+ *  Copyright (C) 2001, 2002 Andi Kleen, SuSE Labs.
+ *  Copyright (C) 2008-2009, Red Hat Inc., Ingo Molnar
  */
+#include <linux/magic.h>               /* STACK_END_MAGIC              */
+#include <linux/sched.h>               /* test_thread_flag(), ...      */
+#include <linux/kdebug.h>              /* oops_begin/end, ...          */
+#include <linux/module.h>              /* search_exception_table       */
+#include <linux/bootmem.h>             /* max_low_pfn                  */
+#include <linux/kprobes.h>             /* __kprobes, ...               */
+#include <linux/mmiotrace.h>           /* kmmio_handler, ...           */
 
-#include <linux/signal.h>
-#include <linux/sched.h>
-#include <linux/kernel.h>
-#include <linux/errno.h>
-#include <linux/string.h>
-#include <linux/types.h>
-#include <linux/ptrace.h>
-#include <linux/mman.h>
-#include <linux/mm.h>
-#include <linux/smp.h>
-#include <linux/interrupt.h>
-#include <linux/init.h>
-#include <linux/tty.h>
-#include <linux/vt_kern.h>             /* For unblank_screen() */
-#include <linux/compiler.h>
-#include <linux/highmem.h>
-#include <linux/bootmem.h>             /* for max_low_pfn */
-#include <linux/vmalloc.h>
-#include <linux/module.h>
-#include <linux/kprobes.h>
-#include <linux/uaccess.h>
-#include <linux/kdebug.h>
-
-#include <asm/system.h>
-#include <asm/desc.h>
-#include <asm/segment.h>
-#include <asm/pgalloc.h>
-#include <asm/smp.h>
-#include <asm/tlbflush.h>
-#include <asm/proto.h>
-#include <asm-generic/sections.h>
+#include <asm/traps.h>                 /* dotraplinkage, ...           */
+#include <asm/pgalloc.h>               /* pgd_*(), ...                 */
 
 /*
- * Page fault error code bits
- *     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
+ * Page fault error code bits:
+ *
+ *   bit 0 ==   0: no page found       1: protection fault
+ *   bit 1 ==   0: read access         1: write access
+ *   bit 2 ==   0: kernel-mode access  1: user-mode access
+ *   bit 3 ==                          1: use of reserved bit detected
+ *   bit 4 ==                          1: fault was an instruction fetch
  */
-#define PF_PROT                (1<<0)
-#define PF_WRITE       (1<<1)
-#define PF_USER                (1<<2)
-#define PF_RSVD                (1<<3)
-#define PF_INSTR       (1<<4)
+enum x86_pf_error_code {
+
+       PF_PROT         =               1 << 0,
+       PF_WRITE        =               1 << 1,
+       PF_USER         =               1 << 2,
+       PF_RSVD         =               1 << 3,
+       PF_INSTR        =               1 << 4,
+};
+
+/*
+ * Returns 0 if mmiotrace is disabled, or if the fault is not
+ * handled by mmiotrace:
+ */
+static inline int kmmio_fault(struct pt_regs *regs, unsigned long addr)
+{
+       if (unlikely(is_kmmio_active()))
+               if (kmmio_handler(regs, addr) == 1)
+                       return -1;
+       return 0;
+}
 
 static inline int notify_page_fault(struct pt_regs *regs)
 {
-#ifdef CONFIG_KPROBES
        int ret = 0;
 
        /* kprobe_running() needs smp_processor_id() */
-#ifdef CONFIG_X86_32
-       if (!user_mode_vm(regs)) {
-#else
-       if (!user_mode(regs)) {
-#endif
+       if (kprobes_built_in() && !user_mode_vm(regs)) {
                preempt_disable();
                if (kprobe_running() && kprobe_fault_handler(regs, 14))
                        ret = 1;
@@ -67,139 +57,246 @@ static inline int notify_page_fault(struct pt_regs *regs)
        }
 
        return ret;
-#else
-       return 0;
-#endif
 }
 
 /*
- * X86_32
- * Sometimes AMD Athlon/Opteron CPUs report invalid exceptions on prefetch.
- * Check that here and ignore it.
+ * Prefetch quirks:
+ *
+ * 32-bit mode:
+ *
+ *   Sometimes AMD Athlon/Opteron CPUs report invalid exceptions on prefetch.
+ *   Check that here and ignore it.
+ *
+ * 64-bit mode:
  *
- * X86_64
- * Sometimes the CPU reports invalid exceptions on prefetch.
- * Check that here and ignore it.
+ *   Sometimes the CPU reports invalid exceptions on prefetch.
+ *   Check that here and ignore it.
  *
- * Opcode checker based on code by Richard Brunner
+ * Opcode checker based on code by Richard Brunner.
  */
-static int is_prefetch(struct pt_regs *regs, unsigned long addr,
-                      unsigned long error_code)
+static inline int
+check_prefetch_opcode(struct pt_regs *regs, unsigned char *instr,
+                     unsigned char opcode, int *prefetch)
 {
-       unsigned char *instr;
-       int scan_more = 1;
-       int prefetch = 0;
-       unsigned char *max_instr;
+       unsigned char instr_hi = opcode & 0xf0;
+       unsigned char instr_lo = opcode & 0x0f;
 
-#ifdef CONFIG_X86_32
-       if (!(__supported_pte_mask & _PAGE_NX))
-               return 0;
+       switch (instr_hi) {
+       case 0x20:
+       case 0x30:
+               /*
+                * Values 0x26,0x2E,0x36,0x3E are valid x86 prefixes.
+                * In X86_64 long mode, the CPU will signal invalid
+                * opcode if some of these prefixes are present so
+                * X86_64 will never get here anyway
+                */
+               return ((instr_lo & 7) == 0x6);
+#ifdef CONFIG_X86_64
+       case 0x40:
+               /*
+                * In AMD64 long mode 0x40..0x4F are valid REX prefixes
+                * Need to figure out under what instruction mode the
+                * instruction was issued. Could check the LDT for lm,
+                * but for now it's good enough to assume that long
+                * mode only uses well known segments or kernel.
+                */
+               return (!user_mode(regs)) || (regs->cs == __USER_CS);
 #endif
+       case 0x60:
+               /* 0x64 thru 0x67 are valid prefixes in all modes. */
+               return (instr_lo & 0xC) == 0x4;
+       case 0xF0:
+               /* 0xF0, 0xF2, 0xF3 are valid prefixes in all modes. */
+               return !instr_lo || (instr_lo>>1) == 1;
+       case 0x00:
+               /* Prefetch instruction is 0x0F0D or 0x0F18 */
+               if (probe_kernel_address(instr, opcode))
+                       return 0;
+
+               *prefetch = (instr_lo == 0xF) &&
+                       (opcode == 0x0D || opcode == 0x18);
+               return 0;
+       default:
+               return 0;
+       }
+}
 
-       /* If it was a exec fault on NX page, ignore */
+static int
+is_prefetch(struct pt_regs *regs, unsigned long error_code, unsigned long addr)
+{
+       unsigned char *max_instr;
+       unsigned char *instr;
+       int prefetch = 0;
+
+       /*
+        * If it was a exec (instruction fetch) fault on NX page, then
+        * do not ignore the fault:
+        */
        if (error_code & PF_INSTR)
                return 0;
 
-       instr = (unsigned char *)convert_ip_to_linear(current, regs);
+       instr = (void *)convert_ip_to_linear(current, regs);
        max_instr = instr + 15;
 
        if (user_mode(regs) && instr >= (unsigned char *)TASK_SIZE)
                return 0;
 
-       while (scan_more && instr < max_instr) {
+       while (instr < max_instr) {
                unsigned char opcode;
-               unsigned char instr_hi;
-               unsigned char instr_lo;
 
                if (probe_kernel_address(instr, opcode))
                        break;
 
-               instr_hi = opcode & 0xf0;
-               instr_lo = opcode & 0x0f;
                instr++;
 
-               switch (instr_hi) {
-               case 0x20:
-               case 0x30:
-                       /*
-                        * Values 0x26,0x2E,0x36,0x3E are valid x86 prefixes.
-                        * In X86_64 long mode, the CPU will signal invalid
-                        * opcode if some of these prefixes are present so
-                        * X86_64 will never get here anyway
-                        */
-                       scan_more = ((instr_lo & 7) == 0x6);
-                       break;
-#ifdef CONFIG_X86_64
-               case 0x40:
-                       /*
-                        * In AMD64 long mode 0x40..0x4F are valid REX prefixes
-                        * Need to figure out under what instruction mode the
-                        * instruction was issued. Could check the LDT for lm,
-                        * but for now it's good enough to assume that long
-                        * mode only uses well known segments or kernel.
-                        */
-                       scan_more = (!user_mode(regs)) || (regs->cs == __USER_CS);
-                       break;
-#endif
-               case 0x60:
-                       /* 0x64 thru 0x67 are valid prefixes in all modes. */
-                       scan_more = (instr_lo & 0xC) == 0x4;
-                       break;
-               case 0xF0:
-                       /* 0xF0, 0xF2, 0xF3 are valid prefixes in all modes. */
-                       scan_more = !instr_lo || (instr_lo>>1) == 1;
-                       break;
-               case 0x00:
-                       /* Prefetch instruction is 0x0F0D or 0x0F18 */
-                       scan_more = 0;
-
-                       if (probe_kernel_address(instr, opcode))
-                               break;
-                       prefetch = (instr_lo == 0xF) &&
-                               (opcode == 0x0D || opcode == 0x18);
-                       break;
-               default:
-                       scan_more = 0;
+               if (!check_prefetch_opcode(regs, instr, opcode, &prefetch))
                        break;
-               }
        }
        return prefetch;
 }
 
-static void force_sig_info_fault(int si_signo, int si_code,
-       unsigned long address, struct task_struct *tsk)
+static void
+force_sig_info_fault(int si_signo, int si_code, unsigned long address,
+                    struct task_struct *tsk)
 {
        siginfo_t info;
 
-       info.si_signo = si_signo;
-       info.si_errno = 0;
-       info.si_code = si_code;
-       info.si_addr = (void __user *)address;
+       info.si_signo   = si_signo;
+       info.si_errno   = 0;
+       info.si_code    = si_code;
+       info.si_addr    = (void __user *)address;
+
        force_sig_info(si_signo, &info, tsk);
 }
 
-#ifdef CONFIG_X86_64
-static int bad_address(void *p)
+DEFINE_SPINLOCK(pgd_lock);
+LIST_HEAD(pgd_list);
+
+#ifdef CONFIG_X86_32
+static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address)
 {
-       unsigned long dummy;
-       return probe_kernel_address((unsigned long *)p, dummy);
+       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;
 }
-#endif
 
-void dump_pagetable(unsigned long address)
+void vmalloc_sync_all(void)
+{
+       unsigned long address;
+
+       if (SHARED_KERNEL_PMD)
+               return;
+
+       for (address = VMALLOC_START & PMD_MASK;
+            address >= TASK_SIZE && address < FIXADDR_TOP;
+            address += PMD_SIZE) {
+
+               unsigned long flags;
+               struct page *page;
+
+               spin_lock_irqsave(&pgd_lock, flags);
+               list_for_each_entry(page, &pgd_list, lru) {
+                       if (!vmalloc_sync_one(page_address(page), address))
+                               break;
+               }
+               spin_unlock_irqrestore(&pgd_lock, flags);
+       }
+}
+
+/*
+ * 32-bit:
+ *
+ *   Handle a fault on the vmalloc or module mapping area
+ */
+static noinline int vmalloc_fault(unsigned long address)
+{
+       unsigned long pgd_paddr;
+       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_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;
+}
+
+/*
+ * Did it hit the DOS screen memory VA from vm86 mode?
+ */
+static inline void
+check_v8086_mode(struct pt_regs *regs, unsigned long address,
+                struct task_struct *tsk)
+{
+       unsigned long bit;
+
+       if (!v8086_mode(regs))
+               return;
+
+       bit = (address - 0xA0000) >> PAGE_SHIFT;
+       if (bit < 32)
+               tsk->thread.screen_bitmap |= 1 << bit;
+}
+
+static void dump_pagetable(unsigned long address)
 {
-#ifdef CONFIG_X86_32
        __typeof__(pte_val(__pte(0))) page;
 
        page = read_cr3();
        page = ((__typeof__(page) *) __va(page))[address >> PGDIR_SHIFT];
+
 #ifdef CONFIG_X86_PAE
        printk("*pdpt = %016Lx ", page);
        if ((page >> PAGE_SHIFT) < max_low_pfn
            && page & _PAGE_PRESENT) {
                page &= PAGE_MASK;
                page = ((__typeof__(page) *) __va(page))[(address >> PMD_SHIFT)
-                                                        & (PTRS_PER_PMD - 1)];
+                                                       & (PTRS_PER_PMD - 1)];
                printk(KERN_CONT "*pde = %016Lx ", page);
                page &= ~_PAGE_NX;
        }
@@ -211,19 +308,145 @@ void dump_pagetable(unsigned long address)
         * We must not directly access the pte in the highpte
         * case if the page table is located in highmem.
         * And let's rather not kmap-atomic the pte, just in case
-        * it's allocated already.
+        * it's allocated already:
         */
        if ((page >> PAGE_SHIFT) < max_low_pfn
            && (page & _PAGE_PRESENT)
            && !(page & _PAGE_PSE)) {
+
                page &= PAGE_MASK;
                page = ((__typeof__(page) *) __va(page))[(address >> PAGE_SHIFT)
-                                                        & (PTRS_PER_PTE - 1)];
+                                                       & (PTRS_PER_PTE - 1)];
                printk("*pte = %0*Lx ", sizeof(page)*2, (u64)page);
        }
 
        printk("\n");
-#else /* CONFIG_X86_64 */
+}
+
+#else /* CONFIG_X86_64: */
+
+void vmalloc_sync_all(void)
+{
+       unsigned long address;
+
+       for (address = VMALLOC_START & PGDIR_MASK; address <= VMALLOC_END;
+            address += PGDIR_SIZE) {
+
+               const pgd_t *pgd_ref = pgd_offset_k(address);
+               unsigned long flags;
+               struct page *page;
+
+               if (pgd_none(*pgd_ref))
+                       continue;
+
+               spin_lock_irqsave(&pgd_lock, flags);
+               list_for_each_entry(page, &pgd_list, lru) {
+                       pgd_t *pgd;
+                       pgd = (pgd_t *)page_address(page) + pgd_index(address);
+                       if (pgd_none(*pgd))
+                               set_pgd(pgd, *pgd_ref);
+                       else
+                               BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref));
+               }
+               spin_unlock_irqrestore(&pgd_lock, flags);
+       }
+}
+
+/*
+ * 64-bit:
+ *
+ *   Handle a fault on the vmalloc area
+ *
+ * This assumes no large pages in there.
+ */
+static noinline int vmalloc_fault(unsigned long address)
+{
+       pgd_t *pgd, *pgd_ref;
+       pud_t *pud, *pud_ref;
+       pmd_t *pmd, *pmd_ref;
+       pte_t *pte, *pte_ref;
+
+       /* Make sure we are in vmalloc area: */
+       if (!(address >= VMALLOC_START && address < VMALLOC_END))
+               return -1;
+
+       /*
+        * Copy kernel mappings over when needed. This can also
+        * happen within a race in page table update. In the later
+        * case just flush:
+        */
+       pgd = pgd_offset(current->active_mm, address);
+       pgd_ref = pgd_offset_k(address);
+       if (pgd_none(*pgd_ref))
+               return -1;
+
+       if (pgd_none(*pgd))
+               set_pgd(pgd, *pgd_ref);
+       else
+               BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref));
+
+       /*
+        * Below here mismatches are bugs because these lower tables
+        * are shared:
+        */
+
+       pud = pud_offset(pgd, address);
+       pud_ref = pud_offset(pgd_ref, address);
+       if (pud_none(*pud_ref))
+               return -1;
+
+       if (pud_none(*pud) || pud_page_vaddr(*pud) != pud_page_vaddr(*pud_ref))
+               BUG();
+
+       pmd = pmd_offset(pud, address);
+       pmd_ref = pmd_offset(pud_ref, address);
+       if (pmd_none(*pmd_ref))
+               return -1;
+
+       if (pmd_none(*pmd) || pmd_page(*pmd) != pmd_page(*pmd_ref))
+               BUG();
+
+       pte_ref = pte_offset_kernel(pmd_ref, address);
+       if (!pte_present(*pte_ref))
+               return -1;
+
+       pte = pte_offset_kernel(pmd, address);
+
+       /*
+        * Don't use pte_page here, because the mappings can point
+        * outside mem_map, and the NUMA hash lookup cannot handle
+        * that:
+        */
+       if (!pte_present(*pte) || pte_pfn(*pte) != pte_pfn(*pte_ref))
+               BUG();
+
+       return 0;
+}
+
+static const char errata93_warning[] =
+KERN_ERR "******* Your BIOS seems to not contain a fix for K8 errata #93\n"
+KERN_ERR "******* Working around it, but it may cause SEGVs or burn power.\n"
+KERN_ERR "******* Please consider a BIOS update.\n"
+KERN_ERR "******* Disabling USB legacy in the BIOS may also help.\n";
+
+/*
+ * No vm86 mode in 64-bit mode:
+ */
+static inline void
+check_v8086_mode(struct pt_regs *regs, unsigned long address,
+                struct task_struct *tsk)
+{
+}
+
+static int bad_address(void *p)
+{
+       unsigned long dummy;
+
+       return probe_kernel_address((unsigned long *)p, dummy);
+}
+
+static void dump_pagetable(unsigned long address)
+{
        pgd_t *pgd;
        pud_t *pud;
        pmd_t *pmd;
@@ -232,102 +455,73 @@ void dump_pagetable(unsigned long address)
        pgd = (pgd_t *)read_cr3();
 
        pgd = __va((unsigned long)pgd & PHYSICAL_PAGE_MASK);
+
        pgd += pgd_index(address);
-       if (bad_address(pgd)) goto bad;
+       if (bad_address(pgd))
+               goto bad;
+
        printk("PGD %lx ", pgd_val(*pgd));
-       if (!pgd_present(*pgd)) goto ret;
+
+       if (!pgd_present(*pgd))
+               goto out;
 
        pud = pud_offset(pgd, address);
-       if (bad_address(pud)) goto bad;
+       if (bad_address(pud))
+               goto bad;
+
        printk("PUD %lx ", pud_val(*pud));
-       if (!pud_present(*pud)) goto ret;
+       if (!pud_present(*pud) || pud_large(*pud))
+               goto out;
 
        pmd = pmd_offset(pud, address);
-       if (bad_address(pmd)) goto bad;
+       if (bad_address(pmd))
+               goto bad;
+
        printk("PMD %lx ", pmd_val(*pmd));
-       if (!pmd_present(*pmd) || pmd_large(*pmd)) goto ret;
+       if (!pmd_present(*pmd) || pmd_large(*pmd))
+               goto out;
 
        pte = pte_offset_kernel(pmd, address);
-       if (bad_address(pte)) goto bad;
+       if (bad_address(pte))
+               goto bad;
+
        printk("PTE %lx", pte_val(*pte));
-ret:
+out:
        printk("\n");
        return;
 bad:
        printk("BAD\n");
-#endif
 }
 
-#ifdef CONFIG_X86_32
-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;
+#endif /* CONFIG_X86_64 */
 
-       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);
-               arch_flush_lazy_mmu_mode();
-       } else
-               BUG_ON(pmd_page(*pmd) != pmd_page(*pmd_k));
-       return pmd_k;
-}
-#endif
-
-#ifdef CONFIG_X86_64
-static const char errata93_warning[] =
-KERN_ERR "******* Your BIOS seems to not contain a fix for K8 errata #93\n"
-KERN_ERR "******* Working around it, but it may cause SEGVs or burn power.\n"
-KERN_ERR "******* Please consider a BIOS update.\n"
-KERN_ERR "******* Disabling USB legacy in the BIOS may also help.\n";
-#endif
-
-/* Workaround for K8 erratum #93 & buggy BIOS.
-   BIOS SMM functions are required to use a specific workaround
-   to avoid corruption of the 64bit RIP register on C stepping K8.
-   A lot of BIOS that didn't get tested properly miss this.
-   The OS sees this as a page fault with the upper 32bits of RIP cleared.
-   Try to work around it here.
-   Note we only handle faults in kernel here.
-   Does nothing for X86_32
+/*
+ * Workaround for K8 erratum #93 & buggy BIOS.
+ *
+ * BIOS SMM functions are required to use a specific workaround
+ * to avoid corruption of the 64bit RIP register on C stepping K8.
+ *
+ * A lot of BIOS that didn't get tested properly miss this.
+ *
+ * The OS sees this as a page fault with the upper 32bits of RIP cleared.
+ * Try to work around it here.
+ *
+ * Note we only handle faults in kernel here.
+ * Does nothing on 32-bit.
  */
 static int is_errata93(struct pt_regs *regs, unsigned long address)
 {
 #ifdef CONFIG_X86_64
-       static int warned;
        if (address != regs->ip)
                return 0;
+
        if ((address >> 32) != 0)
                return 0;
+
        address |= 0xffffffffUL << 32;
        if ((address >= (u64)_stext && address <= (u64)_etext) ||
            (address >= MODULES_VADDR && address <= MODULES_END)) {
-               if (!warned) {
-                       printk(errata93_warning);
-                       warned = 1;
-               }
+               printk_once(errata93_warning);
                regs->ip = address;
                return 1;
        }
@@ -336,29 +530,29 @@ static int is_errata93(struct pt_regs *regs, unsigned long address)
 }
 
 /*
- * Work around K8 erratum #100 K8 in compat mode occasionally jumps to illegal
- * addresses >4GB.  We catch this in the page fault handler because these
- * addresses are not reachable. Just detect this case and return.  Any code
+ * Work around K8 erratum #100 K8 in compat mode occasionally jumps
+ * to illegal addresses >4GB.
+ *
+ * We catch this in the page fault handler because these addresses
+ * are not reachable. Just detect this case and return.  Any code
  * segment in LDT is compatibility mode.
  */
 static int is_errata100(struct pt_regs *regs, unsigned long address)
 {
 #ifdef CONFIG_X86_64
-       if ((regs->cs == __USER32_CS || (regs->cs & (1<<2))) &&
-           (address >> 32))
+       if ((regs->cs == __USER32_CS || (regs->cs & (1<<2))) && (address >> 32))
                return 1;
 #endif
        return 0;
 }
 
-void do_invalid_op(struct pt_regs *, unsigned long);
-
 static int is_f00f_bug(struct pt_regs *regs, unsigned long address)
 {
 #ifdef CONFIG_X86_F00F_BUG
        unsigned long nr;
+
        /*
-        * Pentium F0 0F C7 C8 bug workaround.
+        * Pentium F0 0F C7 C8 bug workaround:
         */
        if (boot_cpu_data.f00f_bug) {
                nr = (address - idt_descr.address) >> 3;
@@ -372,77 +566,303 @@ static int is_f00f_bug(struct pt_regs *regs, unsigned long address)
        return 0;
 }
 
-static void show_fault_oops(struct pt_regs *regs, unsigned long error_code,
-                           unsigned long address)
+static const char nx_warning[] = KERN_CRIT
+"kernel tried to execute NX-protected page - exploit attempt? (uid: %d)\n";
+
+static void
+show_fault_oops(struct pt_regs *regs, unsigned long error_code,
+               unsigned long address)
 {
-#ifdef CONFIG_X86_32
        if (!oops_may_print())
                return;
-#endif
 
-#ifdef CONFIG_X86_PAE
        if (error_code & PF_INSTR) {
                unsigned int level;
+
                pte_t *pte = lookup_address(address, &level);
 
                if (pte && pte_present(*pte) && !pte_exec(*pte))
-                       printk(KERN_CRIT "kernel tried to execute "
-                               "NX-protected page - exploit attempt? "
-                               "(uid: %d)\n", current->uid);
+                       printk(nx_warning, current_uid());
        }
-#endif
 
        printk(KERN_ALERT "BUG: unable to handle kernel ");
        if (address < PAGE_SIZE)
                printk(KERN_CONT "NULL pointer dereference");
        else
                printk(KERN_CONT "paging request");
-#ifdef CONFIG_X86_32
-       printk(KERN_CONT " at %08lx\n", address);
-#else
-       printk(KERN_CONT " at %016lx\n", address);
-#endif
+
+       printk(KERN_CONT " at %p\n", (void *) address);
        printk(KERN_ALERT "IP:");
        printk_address(regs->ip, 1);
+
        dump_pagetable(address);
 }
 
-#ifdef CONFIG_X86_64
-static noinline void pgtable_bad(unsigned long address, struct pt_regs *regs,
-                                unsigned long error_code)
+static noinline void
+pgtable_bad(struct pt_regs *regs, unsigned long error_code,
+           unsigned long address)
 {
-       unsigned long flags = oops_begin();
        struct task_struct *tsk;
+       unsigned long flags;
+       int sig;
+
+       flags = oops_begin();
+       tsk = current;
+       sig = SIGKILL;
 
        printk(KERN_ALERT "%s: Corrupted page table at address %lx\n",
-              current->comm, address);
+              tsk->comm, address);
        dump_pagetable(address);
-       tsk = current;
-       tsk->thread.cr2 = address;
-       tsk->thread.trap_no = 14;
-       tsk->thread.error_code = error_code;
+
+       tsk->thread.cr2         = address;
+       tsk->thread.trap_no     = 14;
+       tsk->thread.error_code  = error_code;
+
        if (__die("Bad pagetable", regs, error_code))
-               regs = NULL;
-       oops_end(flags, regs, SIGKILL);
+               sig = 0;
+
+       oops_end(flags, regs, sig);
+}
+
+static noinline void
+no_context(struct pt_regs *regs, unsigned long error_code,
+          unsigned long address)
+{
+       struct task_struct *tsk = current;
+       unsigned long *stackend;
+       unsigned long flags;
+       int sig;
+
+       /* Are we prepared to handle this kernel fault? */
+       if (fixup_exception(regs))
+               return;
+
+       /*
+        * 32-bit:
+        *
+        *   Valid to do another page fault here, because if this fault
+        *   had been triggered by is_prefetch fixup_exception would have
+        *   handled it.
+        *
+        * 64-bit:
+        *
+        *   Hall of shame of CPU/BIOS bugs.
+        */
+       if (is_prefetch(regs, error_code, address))
+               return;
+
+       if (is_errata93(regs, address))
+               return;
+
+       /*
+        * Oops. The kernel tried to access some bad page. We'll have to
+        * terminate things with extreme prejudice:
+        */
+       flags = oops_begin();
+
+       show_fault_oops(regs, error_code, address);
+
+       stackend = end_of_stack(tsk);
+       if (*stackend != STACK_END_MAGIC)
+               printk(KERN_ALERT "Thread overran stack, or stack corrupted\n");
+
+       tsk->thread.cr2         = address;
+       tsk->thread.trap_no     = 14;
+       tsk->thread.error_code  = error_code;
+
+       sig = SIGKILL;
+       if (__die("Oops", regs, error_code))
+               sig = 0;
+
+       /* Executive summary in case the body of the oops scrolled away */
+       printk(KERN_EMERG "CR2: %016lx\n", address);
+
+       oops_end(flags, regs, sig);
 }
-#endif
 
 /*
- * Handle a spurious fault caused by a stale TLB entry.  This allows
- * us to lazily refresh the TLB when increasing the permissions of a
- * kernel page (RO -> RW or NX -> X).  Doing it eagerly is very
- * expensive since that implies doing a full cross-processor TLB
- * flush, even if no stale TLB entries exist on other processors.
+ * Print out info about fatal segfaults, if the show_unhandled_signals
+ * sysctl is set:
+ */
+static inline void
+show_signal_msg(struct pt_regs *regs, unsigned long error_code,
+               unsigned long address, struct task_struct *tsk)
+{
+       if (!unhandled_signal(tsk, SIGSEGV))
+               return;
+
+       if (!printk_ratelimit())
+               return;
+
+       printk(KERN_CONT "%s%s[%d]: segfault at %lx ip %p sp %p error %lx",
+               task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
+               tsk->comm, task_pid_nr(tsk), address,
+               (void *)regs->ip, (void *)regs->sp, error_code);
+
+       print_vma_addr(KERN_CONT " in ", regs->ip);
+
+       printk(KERN_CONT "\n");
+}
+
+static void
+__bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
+                      unsigned long address, int si_code)
+{
+       struct task_struct *tsk = current;
+
+       /* User mode accesses just cause a SIGSEGV */
+       if (error_code & PF_USER) {
+               /*
+                * It's possible to have interrupts off here:
+                */
+               local_irq_enable();
+
+               /*
+                * Valid to do another page fault here because this one came
+                * from user space:
+                */
+               if (is_prefetch(regs, error_code, address))
+                       return;
+
+               if (is_errata100(regs, address))
+                       return;
+
+               if (unlikely(show_unhandled_signals))
+                       show_signal_msg(regs, error_code, address, tsk);
+
+               /* Kernel addresses are always protection faults: */
+               tsk->thread.cr2         = address;
+               tsk->thread.error_code  = error_code | (address >= TASK_SIZE);
+               tsk->thread.trap_no     = 14;
+
+               force_sig_info_fault(SIGSEGV, si_code, address, tsk);
+
+               return;
+       }
+
+       if (is_f00f_bug(regs, address))
+               return;
+
+       no_context(regs, error_code, address);
+}
+
+static noinline void
+bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
+                    unsigned long address)
+{
+       __bad_area_nosemaphore(regs, error_code, address, SEGV_MAPERR);
+}
+
+static void
+__bad_area(struct pt_regs *regs, unsigned long error_code,
+          unsigned long address, int si_code)
+{
+       struct mm_struct *mm = current->mm;
+
+       /*
+        * Something tried to access memory that isn't in our memory map..
+        * Fix it, but check if it's kernel or user first..
+        */
+       up_read(&mm->mmap_sem);
+
+       __bad_area_nosemaphore(regs, error_code, address, si_code);
+}
+
+static noinline void
+bad_area(struct pt_regs *regs, unsigned long error_code, unsigned long address)
+{
+       __bad_area(regs, error_code, address, SEGV_MAPERR);
+}
+
+static noinline void
+bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
+                     unsigned long address)
+{
+       __bad_area(regs, error_code, address, SEGV_ACCERR);
+}
+
+/* TODO: fixup for "mm-invoke-oom-killer-from-page-fault.patch" */
+static void
+out_of_memory(struct pt_regs *regs, unsigned long error_code,
+             unsigned long address)
+{
+       /*
+        * We ran out of memory, call the OOM killer, and return the userspace
+        * (which will retry the fault, or kill us if we got oom-killed):
+        */
+       up_read(&current->mm->mmap_sem);
+
+       pagefault_out_of_memory();
+}
+
+static void
+do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address)
+{
+       struct task_struct *tsk = current;
+       struct mm_struct *mm = tsk->mm;
+
+       up_read(&mm->mmap_sem);
+
+       /* Kernel mode? Handle exceptions or die: */
+       if (!(error_code & PF_USER))
+               no_context(regs, error_code, address);
+
+       /* User-space => ok to do another page fault: */
+       if (is_prefetch(regs, error_code, address))
+               return;
+
+       tsk->thread.cr2         = address;
+       tsk->thread.error_code  = error_code;
+       tsk->thread.trap_no     = 14;
+
+       force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk);
+}
+
+static noinline void
+mm_fault_error(struct pt_regs *regs, unsigned long error_code,
+              unsigned long address, unsigned int fault)
+{
+       if (fault & VM_FAULT_OOM) {
+               out_of_memory(regs, error_code, address);
+       } else {
+               if (fault & VM_FAULT_SIGBUS)
+                       do_sigbus(regs, error_code, address);
+               else
+                       BUG();
+       }
+}
+
+static int spurious_fault_check(unsigned long error_code, pte_t *pte)
+{
+       if ((error_code & PF_WRITE) && !pte_write(*pte))
+               return 0;
+
+       if ((error_code & PF_INSTR) && !pte_exec(*pte))
+               return 0;
+
+       return 1;
+}
+
+/*
+ * Handle a spurious fault caused by a stale TLB entry.
+ *
+ * This allows us to lazily refresh the TLB when increasing the
+ * permissions of a kernel page (RO -> RW or NX -> X).  Doing it
+ * eagerly is very expensive since that implies doing a full
+ * cross-processor TLB flush, even if no stale TLB entries exist
+ * on other processors.
+ *
  * There are no security implications to leaving a stale TLB when
  * increasing the permissions on a page.
  */
-static int spurious_fault(unsigned long address,
-                         unsigned long error_code)
+static noinline int
+spurious_fault(unsigned long error_code, unsigned long address)
 {
        pgd_t *pgd;
        pud_t *pud;
        pmd_t *pmd;
        pte_t *pte;
+       int ret;
 
        /* Reserved-bit violation or user access to kernel space? */
        if (error_code & (PF_USER | PF_RSVD))
@@ -456,140 +876,86 @@ static int spurious_fault(unsigned long address,
        if (!pud_present(*pud))
                return 0;
 
+       if (pud_large(*pud))
+               return spurious_fault_check(error_code, (pte_t *) pud);
+
        pmd = pmd_offset(pud, address);
        if (!pmd_present(*pmd))
                return 0;
 
+       if (pmd_large(*pmd))
+               return spurious_fault_check(error_code, (pte_t *) pmd);
+
        pte = pte_offset_kernel(pmd, address);
        if (!pte_present(*pte))
                return 0;
 
-       if ((error_code & PF_WRITE) && !pte_write(*pte))
+       ret = spurious_fault_check(error_code, pte);
+       if (!ret)
                return 0;
-       if ((error_code & PF_INSTR) && !pte_exec(*pte))
-               return 0;
-
-       return 1;
-}
 
-/*
- * X86_32
- * Handle a fault on the vmalloc or module mapping area
- *
- * X86_64
- * Handle a fault on the vmalloc area
- *
- * This assumes no large pages in there.
- */
-static int vmalloc_fault(unsigned long address)
-{
-#ifdef CONFIG_X86_32
-       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..
+        * Make sure we have permissions in PMD.
+        * If not, then there's a bug in the page tables:
         */
-       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;
-#else
-       pgd_t *pgd, *pgd_ref;
-       pud_t *pud, *pud_ref;
-       pmd_t *pmd, *pmd_ref;
-       pte_t *pte, *pte_ref;
+       ret = spurious_fault_check(error_code, (pte_t *) pmd);
+       WARN_ONCE(!ret, "PMD has incorrect permission bits\n");
 
-       /* Make sure we are in vmalloc area */
-       if (!(address >= VMALLOC_START && address < VMALLOC_END))
-               return -1;
+       return ret;
+}
 
-       /* Copy kernel mappings over when needed. This can also
-          happen within a race in page table update. In the later
-          case just flush. */
+int show_unhandled_signals = 1;
 
-       pgd = pgd_offset(current->mm ?: &init_mm, address);
-       pgd_ref = pgd_offset_k(address);
-       if (pgd_none(*pgd_ref))
-               return -1;
-       if (pgd_none(*pgd))
-               set_pgd(pgd, *pgd_ref);
-       else
-               BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref));
+static inline int
+access_error(unsigned long error_code, int write, struct vm_area_struct *vma)
+{
+       if (write) {
+               /* write, present and write, not present: */
+               if (unlikely(!(vma->vm_flags & VM_WRITE)))
+                       return 1;
+               return 0;
+       }
 
-       /* Below here mismatches are bugs because these lower tables
-          are shared */
+       /* read, present: */
+       if (unlikely(error_code & PF_PROT))
+               return 1;
+
+       /* read, not present: */
+       if (unlikely(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))))
+               return 1;
 
-       pud = pud_offset(pgd, address);
-       pud_ref = pud_offset(pgd_ref, address);
-       if (pud_none(*pud_ref))
-               return -1;
-       if (pud_none(*pud) || pud_page_vaddr(*pud) != pud_page_vaddr(*pud_ref))
-               BUG();
-       pmd = pmd_offset(pud, address);
-       pmd_ref = pmd_offset(pud_ref, address);
-       if (pmd_none(*pmd_ref))
-               return -1;
-       if (pmd_none(*pmd) || pmd_page(*pmd) != pmd_page(*pmd_ref))
-               BUG();
-       pte_ref = pte_offset_kernel(pmd_ref, address);
-       if (!pte_present(*pte_ref))
-               return -1;
-       pte = pte_offset_kernel(pmd, address);
-       /* Don't use pte_page here, because the mappings can point
-          outside mem_map, and the NUMA hash lookup cannot handle
-          that. */
-       if (!pte_present(*pte) || pte_pfn(*pte) != pte_pfn(*pte_ref))
-               BUG();
        return 0;
-#endif
 }
 
-int show_unhandled_signals = 1;
+static int fault_in_kernel_space(unsigned long address)
+{
+       return address >= TASK_SIZE_MAX;
+}
 
 /*
  * This routine handles page faults.  It determines the address,
  * and the problem, and then passes it off to one of the appropriate
  * routines.
  */
-#ifdef CONFIG_X86_64
-asmlinkage
-#endif
-void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
+dotraplinkage void __kprobes
+do_page_fault(struct pt_regs *regs, unsigned long error_code)
 {
-       struct task_struct *tsk;
-       struct mm_struct *mm;
        struct vm_area_struct *vma;
+       struct task_struct *tsk;
        unsigned long address;
-       int write, si_code;
+       struct mm_struct *mm;
+       int write;
        int fault;
-#ifdef CONFIG_X86_64
-       unsigned long flags;
-#endif
-
-       /*
-        * We can fault from pretty much anywhere, with unknown IRQ state.
-        */
-       trace_hardirqs_fixup();
 
        tsk = current;
        mm = tsk->mm;
+
        prefetchw(&mm->mmap_sem);
 
-       /* get the address */
+       /* Get the faulting address: */
        address = read_cr2();
 
-       si_code = SEGV_MAPERR;
-
-       if (notify_page_fault(regs))
+       if (unlikely(kmmio_fault(regs, address)))
                return;
 
        /*
@@ -605,369 +971,147 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
         * (error_code & 4) == 0, and that the fault was not a
         * protection error (error_code & 9) == 0.
         */
-#ifdef CONFIG_X86_32
-       if (unlikely(address >= TASK_SIZE)) {
-#else
-       if (unlikely(address >= TASK_SIZE64)) {
-#endif
+       if (unlikely(fault_in_kernel_space(address))) {
                if (!(error_code & (PF_RSVD|PF_USER|PF_PROT)) &&
                    vmalloc_fault(address) >= 0)
                        return;
 
-               /* Can handle a stale RO->RW TLB */
-               if (spurious_fault(address, error_code))
+               /* Can handle a stale RO->RW TLB: */
+               if (spurious_fault(error_code, address))
                        return;
 
+               /* kprobes don't want to hook the spurious faults: */
+               if (notify_page_fault(regs))
+                       return;
                /*
                 * Don't take the mm semaphore here. If we fixup a prefetch
-                * fault we could otherwise deadlock.
+                * fault we could otherwise deadlock:
                 */
-               goto bad_area_nosemaphore;
-       }
+               bad_area_nosemaphore(regs, error_code, address);
 
+               return;
+       }
 
-#ifdef CONFIG_X86_32
-       /* It's safe to allow irq's after cr2 has been saved and the vmalloc
-          fault has been handled. */
-       if (regs->flags & (X86_EFLAGS_IF|VM_MASK))
-               local_irq_enable();
-
+       /* kprobes don't want to hook the spurious faults: */
+       if (unlikely(notify_page_fault(regs)))
+               return;
        /*
-        * If we're in an interrupt, have no user context or are running in an
-        * atomic region then we must not take the fault.
+        * It's safe to allow irq's after cr2 has been saved and the
+        * vmalloc fault has been handled.
+        *
+        * User-mode registers count as a user access even for any
+        * potential system fault or CPU buglet:
         */
-       if (in_atomic() || !mm)
-               goto bad_area_nosemaphore;
-#else /* CONFIG_X86_64 */
-       if (likely(regs->flags & X86_EFLAGS_IF))
+       if (user_mode_vm(regs)) {
                local_irq_enable();
+               error_code |= PF_USER;
+       } else {
+               if (regs->flags & X86_EFLAGS_IF)
+                       local_irq_enable();
+       }
 
        if (unlikely(error_code & PF_RSVD))
-               pgtable_bad(address, regs, error_code);
+               pgtable_bad(regs, error_code, address);
 
        /*
-        * 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 we're in an interrupt, have no user context or are running
+        * in an atomic region then we must not take the fault:
         */
-       if (unlikely(in_atomic() || !mm))
-               goto bad_area_nosemaphore;
+       if (unlikely(in_atomic() || !mm)) {
+               bad_area_nosemaphore(regs, error_code, address);
+               return;
+       }
 
        /*
-        * User-mode registers count as a user access even for any
-        * potential system fault or CPU buglet.
-        */
-       if (user_mode_vm(regs))
-               error_code |= PF_USER;
-again:
-#endif
-       /* 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.  Unfortunately, in the case of an
-        * erroneous fault occurring 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
-        * exceptions table.
+        * 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.  Unfortunately, in the
+        * case of an erroneous fault occurring 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 exceptions table.
         *
         * As the vast majority of faults will be valid we will only perform
-        * the source reference check when there is a possibility of a deadlock.
-        * Attempt to lock the address space, if we cannot we then validate the
-        * source.  If this is invalid we can skip the address space check,
-        * thus avoiding the deadlock.
+        * the source reference check when there is a possibility of a
+        * deadlock. Attempt to lock the address space, if we cannot we then
+        * validate the source. If this is invalid we can skip the address
+        * space check, thus avoiding the deadlock:
         */
-       if (!down_read_trylock(&mm->mmap_sem)) {
+       if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
                if ((error_code & PF_USER) == 0 &&
-                   !search_exception_tables(regs->ip))
-                       goto bad_area_nosemaphore;
+                   !search_exception_tables(regs->ip)) {
+                       bad_area_nosemaphore(regs, error_code, address);
+                       return;
+               }
                down_read(&mm->mmap_sem);
+       } else {
+               /*
+                * The above down_read_trylock() might have succeeded in
+                * which case we'll have missed the might_sleep() from
+                * down_read():
+                */
+               might_sleep();
        }
 
        vma = find_vma(mm, address);
-       if (!vma)
-               goto bad_area;
-       if (vma->vm_start <= address)
+       if (unlikely(!vma)) {
+               bad_area(regs, error_code, address);
+               return;
+       }
+       if (likely(vma->vm_start <= address))
                goto good_area;
-       if (!(vma->vm_flags & VM_GROWSDOWN))
-               goto bad_area;
+       if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
+               bad_area(regs, error_code, address);
+               return;
+       }
        if (error_code & PF_USER) {
                /*
                 * Accessing the stack below %sp is always a bug.
                 * The large cushion allows instructions like enter
-                * and pusha to work.  ("enter $65535,$31" pushes
+                * and pusha to work. ("enter $65535, $31" pushes
                 * 32 pointers and then decrements %sp by 65535.)
                 */
-               if (address + 65536 + 32 * sizeof(unsigned long) < regs->sp)
-                       goto bad_area;
+               if (unlikely(address + 65536 + 32 * sizeof(unsigned long) < regs->sp)) {
+                       bad_area(regs, error_code, address);
+                       return;
+               }
        }
-       if (expand_stack(vma, address))
-               goto bad_area;
-/*
- * Ok, we have a good vm_area for this memory access, so
- * we can handle it..
- */
+       if (unlikely(expand_stack(vma, address))) {
+               bad_area(regs, error_code, address);
+               return;
+       }
+
+       /*
+        * Ok, we have a good vm_area for this memory access, so
+        * we can handle it..
+        */
 good_area:
-       si_code = SEGV_ACCERR;
-       write = 0;
-       switch (error_code & (PF_PROT|PF_WRITE)) {
-       default:        /* 3: write, present */
-               /* fall through */
-       case PF_WRITE:          /* write, not present */
-               if (!(vma->vm_flags & VM_WRITE))
-                       goto bad_area;
-               write++;
-               break;
-       case PF_PROT:           /* read, present */
-               goto bad_area;
-       case 0:                 /* read, not present */
-               if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
-                       goto bad_area;
+       write = error_code & PF_WRITE;
+
+       if (unlikely(access_error(error_code, write, vma))) {
+               bad_area_access_error(regs, error_code, address);
+               return;
        }
 
-#ifdef CONFIG_X86_32
-survive:
-#endif
        /*
         * If for any reason at all we couldn't handle the fault,
         * make sure we exit gracefully rather than endlessly redo
-        * the fault.
+        * the fault:
         */
        fault = handle_mm_fault(mm, vma, address, write);
+
        if (unlikely(fault & VM_FAULT_ERROR)) {
-               if (fault & VM_FAULT_OOM)
-                       goto out_of_memory;
-               else if (fault & VM_FAULT_SIGBUS)
-                       goto do_sigbus;
-               BUG();
+               mm_fault_error(regs, error_code, address, fault);
+               return;
        }
+
        if (fault & VM_FAULT_MAJOR)
                tsk->maj_flt++;
        else
                tsk->min_flt++;
 
-#ifdef CONFIG_X86_32
-       /*
-        * Did it hit the DOS screen memory VA from vm86 mode?
-        */
-       if (v8086_mode(regs)) {
-               unsigned long bit = (address - 0xA0000) >> PAGE_SHIFT;
-               if (bit < 32)
-                       tsk->thread.screen_bitmap |= 1 << bit;
-       }
-#endif
-       up_read(&mm->mmap_sem);
-       return;
+       check_v8086_mode(regs, address, tsk);
 
-/*
- * 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);
-
-bad_area_nosemaphore:
-       /* User mode accesses just cause a SIGSEGV */
-       if (error_code & PF_USER) {
-               /*
-                * It's possible to have interrupts off here.
-                */
-               local_irq_enable();
-
-               /*
-                * Valid to do another page fault here because this one came
-                * from user space.
-                */
-               if (is_prefetch(regs, address, error_code))
-                       return;
-
-               if (is_errata100(regs, address))
-                       return;
-
-               if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
-                   printk_ratelimit()) {
-                       printk(
-#ifdef CONFIG_X86_32
-                       "%s%s[%d]: segfault at %lx ip %08lx sp %08lx error %lx",
-#else
-                       "%s%s[%d]: segfault at %lx ip %lx sp %lx error %lx",
-#endif
-                       task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
-                       tsk->comm, task_pid_nr(tsk), address, regs->ip,
-                       regs->sp, error_code);
-                       print_vma_addr(" in ", regs->ip);
-                       printk("\n");
-               }
-
-               tsk->thread.cr2 = address;
-               /* Kernel addresses are always protection faults */
-               tsk->thread.error_code = error_code | (address >= TASK_SIZE);
-               tsk->thread.trap_no = 14;
-               force_sig_info_fault(SIGSEGV, si_code, address, tsk);
-               return;
-       }
-
-       if (is_f00f_bug(regs, address))
-               return;
-
-no_context:
-       /* Are we prepared to handle this kernel fault?  */
-       if (fixup_exception(regs))
-               return;
-
-       /*
-        * X86_32
-        * Valid to do another page fault here, because if this fault
-        * had been triggered by is_prefetch fixup_exception would have
-        * handled it.
-        *
-        * X86_64
-        * Hall of shame of CPU/BIOS bugs.
-        */
-       if (is_prefetch(regs, address, error_code))
-               return;
-
-       if (is_errata93(regs, address))
-               return;
-
-/*
- * Oops. The kernel tried to access some bad page. We'll have to
- * terminate things with extreme prejudice.
- */
-#ifdef CONFIG_X86_32
-       bust_spinlocks(1);
-#else
-       flags = oops_begin();
-#endif
-
-       show_fault_oops(regs, error_code, address);
-
-       tsk->thread.cr2 = address;
-       tsk->thread.trap_no = 14;
-       tsk->thread.error_code = error_code;
-
-#ifdef CONFIG_X86_32
-       die("Oops", regs, error_code);
-       bust_spinlocks(0);
-       do_exit(SIGKILL);
-#else
-       if (__die("Oops", regs, error_code))
-               regs = NULL;
-       /* Executive summary in case the body of the oops scrolled away */
-       printk(KERN_EMERG "CR2: %016lx\n", address);
-       oops_end(flags, regs, SIGKILL);
-#endif
-
-/*
- * We ran out of memory, or some other thing happened to us that made
- * us unable to handle the page fault gracefully.
- */
-out_of_memory:
-       up_read(&mm->mmap_sem);
-       if (is_global_init(tsk)) {
-               yield();
-#ifdef CONFIG_X86_32
-               down_read(&mm->mmap_sem);
-               goto survive;
-#else
-               goto again;
-#endif
-       }
-
-       printk("VM: killing process %s\n", tsk->comm);
-       if (error_code & PF_USER)
-               do_group_exit(SIGKILL);
-       goto no_context;
-
-do_sigbus:
-       up_read(&mm->mmap_sem);
-
-       /* Kernel mode? Handle exceptions or die */
-       if (!(error_code & PF_USER))
-               goto no_context;
-#ifdef CONFIG_X86_32
-       /* User space => ok to do another page fault */
-       if (is_prefetch(regs, address, error_code))
-               return;
-#endif
-       tsk->thread.cr2 = address;
-       tsk->thread.error_code = error_code;
-       tsk->thread.trap_no = 14;
-       force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk);
-}
-
-DEFINE_SPINLOCK(pgd_lock);
-LIST_HEAD(pgd_list);
-
-void vmalloc_sync_all(void)
-{
-#ifdef CONFIG_X86_32
-       /*
-        * 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;
-
-       if (SHARED_KERNEL_PMD)
-               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);
-                       list_for_each_entry(page, &pgd_list, lru) {
-                               if (!vmalloc_sync_one(page_address(page),
-                                                     address))
-                                       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;
-       }
-#else /* CONFIG_X86_64 */
-       /*
-        * 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 = VMALLOC_START & PGDIR_MASK;
-       unsigned long address;
-
-       for (address = start; address <= VMALLOC_END; address += PGDIR_SIZE) {
-               if (!test_bit(pgd_index(address), insync)) {
-                       const pgd_t *pgd_ref = pgd_offset_k(address);
-                       struct page *page;
-
-                       if (pgd_none(*pgd_ref))
-                               continue;
-                       spin_lock(&pgd_lock);
-                       list_for_each_entry(page, &pgd_list, lru) {
-                               pgd_t *pgd;
-                               pgd = (pgd_t *)page_address(page) + pgd_index(address);
-                               if (pgd_none(*pgd))
-                                       set_pgd(pgd, *pgd_ref);
-                               else
-                                       BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref));
-                       }
-                       spin_unlock(&pgd_lock);
-                       set_bit(pgd_index(address), insync);
-               }
-               if (address == start)
-                       start = address + PGDIR_SIZE;
-       }
-       /* Check that there is no need to do the same for the modules area. */
-       BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
-       BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
-                               (__START_KERNEL & PGDIR_MASK)));
-#endif
 }