x86: unify fault_32|64.c

Unify includes in moved fault.c.

Modify Makefiles to pick up unified file.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/mm/Makefile_32

@@ -2,7 +2,7 @@
 # Makefile for the linux i386-specific parts of the memory manager.
 #
 
-obj-y	:= init_32.o pgtable_32.o fault_32.o ioremap.o extable.o pageattr.o mmap.o
+obj-y	:= init_32.o pgtable_32.o fault.o ioremap.o extable.o pageattr.o mmap.o
 
 obj-$(CONFIG_NUMA) += discontig_32.o
 obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o

arch/x86/mm/Makefile_64

@@ -2,7 +2,7 @@
 # Makefile for the linux x86_64-specific parts of the memory manager.
 #
 
-obj-y	 := init_64.o fault_64.o ioremap.o extable.o pageattr.o mmap.o
+obj-y	 := init_64.o fault.o ioremap.o extable.o pageattr.o mmap.o
 obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
 obj-$(CONFIG_NUMA) += numa_64.o
 obj-$(CONFIG_K8_NUMA) += k8topology_64.o

arch/x86/mm/fault_64.c → arch/x86/mm/fault.c

@@ -18,6 +18,8 @@
 #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>
@@ -25,6 +27,8 @@
 #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>
@@ -88,16 +92,15 @@ static int is_prefetch(struct pt_regs *regs, unsigned long addr,
 	unsigned char *max_instr;
 
 #ifdef CONFIG_X86_32
-	if (unlikely(boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
-		     boot_cpu_data.x86 >= 6)) {
-		/* Catch an obscure case of prefetch inside an NX page. */
-		if (nx_enabled && (error_code & PF_INSTR))
-			return 0;
-	} else {
+# ifdef CONFIG_X86_PAE
+	/* If it was a exec fault on NX page, ignore */
+	if (nx_enabled && (error_code & PF_INSTR))
 		return 0;
-	}
-#else
-	/* If it was a exec fault ignore */
+# else
+	return 0;
+# endif
+#else /* CONFIG_X86_64 */
+	/* If it was a exec fault on NX page, ignore */
 	if (error_code & PF_INSTR)
 		return 0;
 #endif

arch/x86/mm/fault_32.c

@@ -1,949 +0,0 @@
-/*
- *  Copyright (C) 1995  Linus Torvalds
- */
-
-#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/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>
-
-/*
- * 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
- */
-#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)
-
-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
-		preempt_disable();
-		if (kprobe_running() && kprobe_fault_handler(regs, 14))
-			ret = 1;
-		preempt_enable();
-	}
-
-	return ret;
-#else
-	return 0;
-#endif
-}
-
-/*
- * X86_32
- * Sometimes AMD Athlon/Opteron CPUs report invalid exceptions on prefetch.
- * Check that here and ignore it.
- *
- * X86_64
- * Sometimes the CPU reports invalid exceptions on prefetch.
- * Check that here and ignore it.
- *
- * Opcode checker based on code by Richard Brunner
- */
-static int is_prefetch(struct pt_regs *regs, unsigned long addr,
-		       unsigned long error_code)
-{
-	unsigned char *instr;
-	int scan_more = 1;
-	int prefetch = 0;
-	unsigned char *max_instr;
-
-#ifdef CONFIG_X86_32
-	if (unlikely(boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
-		     boot_cpu_data.x86 >= 6)) {
-		/* Catch an obscure case of prefetch inside an NX page. */
-		if (nx_enabled && (error_code & PF_INSTR))
-			return 0;
-	} else {
-		return 0;
-	}
-#else
-	/* If it was a exec fault ignore */
-	if (error_code & PF_INSTR)
-		return 0;
-#endif
-
-	instr = (unsigned char *)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) {
-		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;
-			break;
-		}
-	}
-	return prefetch;
-}
-
-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;
-	force_sig_info(si_signo, &info, tsk);
-}
-
-#ifdef CONFIG_X86_64
-static int bad_address(void *p)
-{
-	unsigned long dummy;
-	return probe_kernel_address((unsigned long *)p, dummy);
-}
-#endif
-
-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)];
-		printk(KERN_CONT "*pde = %016Lx ", page);
-		page &= ~_PAGE_NX;
-	}
-#else
-	printk("*pde = %08lx ", page);
-#endif
-
-	/*
-	 * 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.
-	 */
-	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)];
-		printk("*pte = %0*Lx ", sizeof(page)*2, (u64)page);
-	}
-
-	printk("\n");
-#else /* CONFIG_X86_64 */
-	pgd_t *pgd;
-	pud_t *pud;
-	pmd_t *pmd;
-	pte_t *pte;
-
-	pgd = (pgd_t *)read_cr3();
-
-	pgd = __va((unsigned long)pgd & PHYSICAL_PAGE_MASK);
-	pgd += pgd_index(address);
-	if (bad_address(pgd)) goto bad;
-	printk("PGD %lx ", pgd_val(*pgd));
-	if (!pgd_present(*pgd)) goto ret;
-
-	pud = pud_offset(pgd, address);
-	if (bad_address(pud)) goto bad;
-	printk("PUD %lx ", pud_val(*pud));
-	if (!pud_present(*pud))	goto ret;
-
-	pmd = pmd_offset(pud, address);
-	if (bad_address(pmd)) goto bad;
-	printk("PMD %lx ", pmd_val(*pmd));
-	if (!pmd_present(*pmd) || pmd_large(*pmd)) goto ret;
-
-	pte = pte_offset_kernel(pmd, address);
-	if (bad_address(pte)) goto bad;
-	printk("PTE %lx", pte_val(*pte));
-ret:
-	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;
-
-	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
- */
-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;
-		}
-		regs->ip = address;
-		return 1;
-	}
-#endif
-	return 0;
-}
-
-/*
- * 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))
-		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.
-	 */
-	if (boot_cpu_data.f00f_bug) {
-		nr = (address - idt_descr.address) >> 3;
-
-		if (nr == 6) {
-			do_invalid_op(regs, 0);
-			return 1;
-		}
-	}
-#endif
-	return 0;
-}
-
-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;
-
-#ifdef CONFIG_X86_PAE
-	if (error_code & PF_INSTR) {
-		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);
-	}
-#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");
-	printk(KERN_CONT " at %08lx\n", address);
-
-	printk(KERN_ALERT "IP:");
-	printk_address(regs->ip, 1);
-	dump_pagetable(address);
-#else /* CONFIG_X86_64 */
-	printk(KERN_ALERT "BUG: unable to handle kernel ");
-	if (address < PAGE_SIZE)
-		printk(KERN_CONT "NULL pointer dereference");
-	else
-		printk(KERN_CONT "paging request");
-	printk(KERN_CONT " at %016lx\n", address);
-
-	printk(KERN_ALERT "IP:");
-	printk_address(regs->ip, 1);
-	dump_pagetable(address);
-#endif
-}
-
-#ifdef CONFIG_X86_64
-static noinline void pgtable_bad(unsigned long address, struct pt_regs *regs,
-				 unsigned long error_code)
-{
-	unsigned long flags = oops_begin();
-	struct task_struct *tsk;
-
-	printk(KERN_ALERT "%s: Corrupted page table at address %lx\n",
-	       current->comm, address);
-	dump_pagetable(address);
-	tsk = current;
-	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);
-}
-#endif
-
-/*
- * 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..
-	 */
-	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;
-
-	/* 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->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));
-
-	/* 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;
-#endif
-}
-
-int show_unhandled_signals = 1;
-
-/*
- * 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)
-{
-	struct task_struct *tsk;
-	struct mm_struct *mm;
-	struct vm_area_struct *vma;
-	unsigned long address;
-	int write, si_code;
-	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 */
-	address = read_cr2();
-
-	si_code = SEGV_MAPERR;
-
-	if (notify_page_fault(regs))
-		return;
-
-	/*
-	 * We fault-in kernel-space virtual memory on-demand. The
-	 * 'reference' page table is init_mm.pgd.
-	 *
-	 * NOTE! We MUST NOT take any locks for this case. We may
-	 * be in an interrupt or a critical region, and should
-	 * only copy the information from the master page table,
-	 * nothing more.
-	 *
-	 * 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.
-	 */
-#ifdef CONFIG_X86_32
-	if (unlikely(address >= TASK_SIZE)) {
-		if (!(error_code & (PF_RSVD|PF_USER|PF_PROT)) &&
-		    vmalloc_fault(address) >= 0)
-			return;
-		/*
-		 * Don't take the mm semaphore here. If we fixup a prefetch
-		 * fault we could otherwise deadlock.
-		 */
-		goto bad_area_nosemaphore;
-	}
-
-	/* 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();
-
-	/*
-	 * 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 (in_atomic() || !mm)
-		goto bad_area_nosemaphore;
-#else /* CONFIG_X86_64 */
-	if (unlikely(address >= TASK_SIZE64)) {
-		/*
-		 * Don't check for the module range here: its PML4
-		 * is always initialized because it's shared with the main
-		 * kernel text. Only vmalloc may need PML4 syncups.
-		 */
-		if (!(error_code & (PF_RSVD|PF_USER|PF_PROT)) &&
-		      ((address >= VMALLOC_START && address < VMALLOC_END))) {
-			if (vmalloc_fault(address) >= 0)
-				return;
-		}
-		/*
-		 * Don't take the mm semaphore here. If we fixup a prefetch
-		 * fault we could otherwise deadlock.
-		 */
-		goto bad_area_nosemaphore;
-	}
-	if (likely(regs->flags & X86_EFLAGS_IF))
-		local_irq_enable();
-
-	if (unlikely(error_code & PF_RSVD))
-		pgtable_bad(address, regs, error_code);
-
-	/*
-	 * 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;
-
-	/*
-	 * 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.
-	 *
-	 * 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.
-	 */
-	if (!down_read_trylock(&mm->mmap_sem)) {
-		if ((error_code & PF_USER) == 0 &&
-		    !search_exception_tables(regs->ip))
-			goto bad_area_nosemaphore;
-		down_read(&mm->mmap_sem);
-	}
-
-	vma = find_vma(mm, address);
-	if (!vma)
-		goto bad_area;
-#ifdef CONFIG_X86_32
-	if (vma->vm_start <= address)
-#else
-	if (likely(vma->vm_start <= address))
-#endif
-		goto good_area;
-	if (!(vma->vm_flags & VM_GROWSDOWN))
-		goto bad_area;
-	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
-		 * 32 pointers and then decrements %sp by 65535.)
-		 */
-		if (address + 65536 + 32 * sizeof(unsigned long) < regs->sp)
-			goto bad_area;
-	}
-	if (expand_stack(vma, address))
-		goto bad_area;
-/*
- * 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;
-	}
-
-#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.
-	 */
-	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();
-	}
-	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;
-
-/*
- * 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);
-
-	show_fault_oops(regs, error_code, address);
-
-	tsk->thread.cr2 = address;
-	tsk->thread.trap_no = 14;
-	tsk->thread.error_code = error_code;
-	die("Oops", regs, error_code);
-	bust_spinlocks(0);
-	do_exit(SIGKILL);
-#else /* CONFIG_X86_64 */
-	flags = oops_begin();
-
-	show_fault_oops(regs, error_code, address);
-
-	tsk->thread.cr2 = address;
-	tsk->thread.trap_no = 14;
-	tsk->thread.error_code = error_code;
-	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);
-#ifdef CONFIG_X86_32
-	if (is_global_init(tsk)) {
-		yield();
-		down_read(&mm->mmap_sem);
-		goto survive;
-	}
-#else
-	if (is_global_init(current)) {
-		yield();
-		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);
-}
-
-#ifdef CONFIG_X86_64
-DEFINE_SPINLOCK(pgd_lock);
-LIST_HEAD(pgd_list);
-#endif
-
-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);
-			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;
-	}
-#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
-}