1 files changed, 37 insertions, 12 deletions

diff --git a/arch/i386/mm/fault.c b/arch/i386/mm/fault.c
index bd6fe96cc16..2581575786c 100644
--- a/arch/i386/mm/fault.c
+++ b/arch/i386/mm/fault.c
@@ -27,9 +27,38 @@
 #include <asm/uaccess.h>
 #include <asm/desc.h>
 #include <asm/kdebug.h>
+#include <asm/segment.h>
 
 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)
+{
+	vmalloc_sync_all();
+	return atomic_notifier_chain_register(&notify_page_fault_chain, nb);
+}
+EXPORT_SYMBOL_GPL(register_page_fault_notifier);
+
+int unregister_page_fault_notifier(struct notifier_block *nb)
+{
+	return atomic_notifier_chain_unregister(&notify_page_fault_chain, nb);
+}
+EXPORT_SYMBOL_GPL(unregister_page_fault_notifier);
+
+static inline int notify_page_fault(enum die_val val, const char *str,
+			struct pt_regs *regs, long err, int trap, int sig)
+{
+	struct die_args args = {
+		.regs = regs,
+		.str = str,
+		.err = err,
+		.trapnr = trap,
+		.signr = sig
+	};
+	return atomic_notifier_call_chain(&notify_page_fault_chain, val, &args);
+}
+
 /*
  * Unlock any spinlocks which will prevent us from getting the
  * message out 
@@ -85,10 +114,10 @@ static inline unsigned long get_segment_eip(struct pt_regs *regs,
 	}
 
 	/* The standard kernel/user address space limit. */
-	*eip_limit = (seg & 3) ? USER_DS.seg : KERNEL_DS.seg;
+	*eip_limit = user_mode(regs) ? USER_DS.seg : KERNEL_DS.seg;
 	
 	/* By far the most common cases. */
-	if (likely(seg == __USER_CS || seg == __KERNEL_CS))
+	if (likely(SEGMENT_IS_FLAT_CODE(seg)))
 		return eip;
 
 	/* Check the segment exists, is within the current LDT/GDT size,
@@ -324,7 +353,7 @@ 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_die(DIE_PAGE_FAULT, "page fault", regs, error_code, 14,
+		if (notify_page_fault(DIE_PAGE_FAULT, "page fault", regs, error_code, 14,
 						SIGSEGV) == NOTIFY_STOP)
 			return;
 		/*
@@ -334,7 +363,7 @@ fastcall void __kprobes do_page_fault(struct pt_regs *regs,
 		goto bad_area_nosemaphore;
 	}
 
-	if (notify_die(DIE_PAGE_FAULT, "page fault", regs, error_code, 14,
+	if (notify_page_fault(DIE_PAGE_FAULT, "page fault", regs, error_code, 14,
 					SIGSEGV) == NOTIFY_STOP)
 		return;
 
@@ -355,7 +384,7 @@ fastcall void __kprobes do_page_fault(struct pt_regs *regs,
 	/* 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
-	 * erroneous fault occuring in a code path which already holds mmap_sem
+	 * 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
@@ -402,11 +431,7 @@ good_area:
 	write = 0;
 	switch (error_code & 3) {
 		default:	/* 3: write, present */
-#ifdef TEST_VERIFY_AREA
-			if (regs->cs == KERNEL_CS)
-				printk("WP fault at %08lx\n", regs->eip);
-#endif
-			/* fall through */
+				/* fall through */
 		case 2:		/* write, not present */
 			if (!(vma->vm_flags & VM_WRITE))
 				goto bad_area;
@@ -415,7 +440,7 @@ good_area:
 		case 1:		/* read, present */
 			goto bad_area;
 		case 0:		/* read, not present */
-			if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
+			if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
 				goto bad_area;
 	}
 
@@ -564,7 +589,7 @@ no_context:
  */
 out_of_memory:
 	up_read(&mm->mmap_sem);
-	if (tsk->pid == 1) {
+	if (is_init(tsk)) {
 		yield();
 		down_read(&mm->mmap_sem);
 		goto survive;