4 files changed, 39 insertions, 52 deletions

diff --git a/arch/x86/kernel/kprobes_32.c b/arch/x86/kernel/kprobes_32.c
index e7d0d3c2ef64..06b86e5617f6 100644
--- a/arch/x86/kernel/kprobes_32.c
+++ b/arch/x86/kernel/kprobes_32.c
@@ -584,7 +584,7 @@ out:
         return 1;
 }
 
-static int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
+int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 {
         struct kprobe *cur = kprobe_running();
         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
@@ -666,7 +666,6 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
                         ret = NOTIFY_STOP;
                 break;
         case DIE_GPF:
-        case DIE_PAGE_FAULT:
                 /* kprobe_running() needs smp_processor_id() */
                 preempt_disable();
                 if (kprobe_running() &&
diff --git a/arch/x86/kernel/kprobes_64.c b/arch/x86/kernel/kprobes_64.c
index 62e28e52d784..7c16506d681f 100644
--- a/arch/x86/kernel/kprobes_64.c
+++ b/arch/x86/kernel/kprobes_64.c
@@ -657,7 +657,6 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
                         ret = NOTIFY_STOP;
                 break;
         case DIE_GPF:
-        case DIE_PAGE_FAULT:
                 /* kprobe_running() needs smp_processor_id() */
                 preempt_disable();
                 if (kprobe_running() &&
diff --git a/arch/x86/mm/fault_32.c b/arch/x86/mm/fault_32.c
index fcb38e7f3543..be72c2a5b03b 100644
--- a/arch/x86/mm/fault_32.c
+++ b/arch/x86/mm/fault_32.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/desc.h>
@@ -32,33 +33,27 @@
 
 extern void die(const char *,struct pt_regs *,long);
 
-static ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain);
-
-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_vm(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
 
 /*
  * Return EIP plus the CS segment base.  The segment limit is also
@@ -331,7 +326,7 @@ fastcall void __kprobes do_page_fault(struct pt_regs *regs,
         if (unlikely(address >= TASK_SIZE)) {
                 if (!(error_code & 0x0000000d) && 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
@@ -340,7 +335,7 @@ fastcall 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;
 
         /* It's safe to allow irq's after cr2 has been saved and the vmalloc
diff --git a/arch/x86/mm/fault_64.c b/arch/x86/mm/fault_64.c
index 54816adb8e93..5e0e54906c48 100644
--- 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.
@@ -345,7 +339,7 @@ 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
@@ -354,7 +348,7 @@ 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))