Pull bugzilla-9153 into release branch

[linux-2.6] / arch / x86 / mm / fault_64.c

diff --git a/arch/x86/mm/fault_64.c b/arch/x86/mm/fault_64.c
index 54816adb8e933c8c09e41afcf3008331afb5adc6..0e26230669ca21aabb92a60f134100d8f453f5fc 100644 (file)
--- a/arch/x86/mm/fault_64.c
+++ b/arch/x86/mm/fault_64.c
@@ -25,6 +25,7 @@
 #include <linux/kprobes.h>
 #include <linux/uaccess.h>
 #include <linux/kdebug.h>
+#include <linux/kprobes.h>
 
 #include <asm/system.h>
 #include <asm/pgalloc.h>
@@ -40,34 +41,27 @@
 #define PF_RSVD        (1<<3)
 #define PF_INSTR       (1<<4)
 
-static ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain);
-
-/* Hook to register for page fault notifications */
-int register_page_fault_notifier(struct notifier_block *nb)
+#ifdef CONFIG_KPROBES
+static inline int notify_page_fault(struct pt_regs *regs)
 {
-       vmalloc_sync_all();
-       return atomic_notifier_chain_register(&notify_page_fault_chain, nb);
-}
-EXPORT_SYMBOL_GPL(register_page_fault_notifier);
+       int ret = 0;
+
+       /* kprobe_running() needs smp_processor_id() */
+       if (!user_mode(regs)) {
+               preempt_disable();
+               if (kprobe_running() && kprobe_fault_handler(regs, 14))
+                       ret = 1;
+               preempt_enable();
+       }
 
-int unregister_page_fault_notifier(struct notifier_block *nb)
-{
-       return atomic_notifier_chain_unregister(&notify_page_fault_chain, nb);
+       return ret;
 }
-EXPORT_SYMBOL_GPL(unregister_page_fault_notifier);
-
-static inline int notify_page_fault(struct pt_regs *regs, long err)
+#else
+static inline int notify_page_fault(struct pt_regs *regs)
 {
-       struct die_args args = {
-               .regs = regs,
-               .str = "page fault",
-               .err = err,
-               .trapnr = 14,
-               .signr = SIGSEGV
-       };
-       return atomic_notifier_call_chain(&notify_page_fault_chain,
-                                         DIE_PAGE_FAULT, &args);
+       return 0;
 }
+#endif
 
 /* Sometimes the CPU reports invalid exceptions on prefetch.
    Check that here and ignore.
@@ -175,7 +169,7 @@ void dump_pagetable(unsigned long address)
        pmd = pmd_offset(pud, address);
        if (bad_address(pmd)) goto bad;
        printk("PMD %lx ", pmd_val(*pmd));
-       if (!pmd_present(*pmd)) goto ret;        
+       if (!pmd_present(*pmd) || pmd_large(*pmd)) goto ret;
 
        pte = pte_offset_kernel(pmd, address);
        if (bad_address(pte)) goto bad;
@@ -291,7 +285,6 @@ static int vmalloc_fault(unsigned long address)
        return 0;
 }
 
-static int page_fault_trace;
 int show_unhandled_signals = 1;
 
 /*
@@ -311,6 +304,11 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
        unsigned long flags;
        siginfo_t info;
 
+       /*
+        * We can fault from pretty much anywhere, with unknown IRQ state.
+        */
+       trace_hardirqs_fixup();
+
        tsk = current;
        mm = tsk->mm;
        prefetchw(&mm->mmap_sem);
@@ -345,7 +343,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
                        if (vmalloc_fault(address) >= 0)
                                return;
                }
-               if (notify_page_fault(regs, error_code) == NOTIFY_STOP)
+               if (notify_page_fault(regs))
                        return;
                /*
                 * Don't take the mm semaphore here. If we fixup a prefetch
@@ -354,16 +352,12 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
                goto bad_area_nosemaphore;
        }
 
-       if (notify_page_fault(regs, error_code) == NOTIFY_STOP)
+       if (notify_page_fault(regs))
                return;
 
        if (likely(regs->eflags & X86_EFLAGS_IF))
                local_irq_enable();
 
-       if (unlikely(page_fault_trace))
-               printk("pagefault rip:%lx rsp:%lx cs:%lu ss:%lu address %lx error %lx\n",
-                      regs->rip,regs->rsp,regs->cs,regs->ss,address,error_code); 
-
        if (unlikely(error_code & PF_RSVD))
                pgtable_bad(address, regs, error_code);
 
@@ -384,7 +378,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
  again:
        /* When running in the kernel we expect faults to occur only to
         * addresses in user space.  All other faults represent errors in the
-        * kernel and should generate an OOPS.  Unfortunatly, in the case of an
+        * 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
@@ -392,7 +386,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
         * exceptions table.
         *
         * As the vast majority of faults will be valid we will only perform
-        * the source reference check when there is a possibilty of a 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.
@@ -494,7 +488,7 @@ bad_area_nosemaphore:
                if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
                    printk_ratelimit()) {
                        printk(
-                      "%s%s[%d]: segfault at %016lx rip %016lx rsp %016lx error %lx\n",
+                      "%s%s[%d]: segfault at %lx rip %lx rsp %lx error %lx\n",
                                        tsk->pid > 1 ? KERN_INFO : KERN_EMERG,
                                        tsk->comm, tsk->pid, address, regs->rip,
                                        regs->rsp, error_code);
@@ -560,7 +554,7 @@ no_context:
  */
 out_of_memory:
        up_read(&mm->mmap_sem);
-       if (is_init(current)) {
+       if (is_global_init(current)) {
                yield();
                goto again;
        }
@@ -627,10 +621,3 @@ void vmalloc_sync_all(void)
        BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) == 
                                (__START_KERNEL & PGDIR_MASK)));
 }
-
-static int __init enable_pagefaulttrace(char *str)
-{
-       page_fault_trace = 1;
-       return 1;
-}
-__setup("pagefaulttrace", enable_pagefaulttrace);