From 731add86ee2de0468432678fc69baa9f52143b1c Mon Sep 17 00:00:00 2001
From: "K.Prasad" <prasad@linux.vnet.ibm.com>
Date: Thu, 28 Jan 2010 16:44:01 +0530
Subject: [PATCH] --- yaml --- r: 182406 b: refs/heads/master c:
 40f9249a73f6c251adea492b1c3d19d39e2a9bda h: refs/heads/master v: v3

---
 [refs]                                | 2 +-
 trunk/arch/x86/include/asm/debugreg.h | 3 +++
 trunk/arch/x86/kernel/traps.c         | 3 +++
 3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index ad7e842706a7..115e3fa03e2d 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 1e12a4a7a3a78bc9c3aaf3486dde3b8ab1cdf465
+refs/heads/master: 40f9249a73f6c251adea492b1c3d19d39e2a9bda
diff --git a/trunk/arch/x86/include/asm/debugreg.h b/trunk/arch/x86/include/asm/debugreg.h
index 8240f76b531e..b81002f23614 100644
--- a/trunk/arch/x86/include/asm/debugreg.h
+++ b/trunk/arch/x86/include/asm/debugreg.h
@@ -14,6 +14,9 @@
    which debugging register was responsible for the trap.  The other bits
    are either reserved or not of interest to us. */
 
+/* Define reserved bits in DR6 which are always set to 1 */
+#define DR6_RESERVED	(0xFFFF0FF0)
+
 #define DR_TRAP0	(0x1)		/* db0 */
 #define DR_TRAP1	(0x2)		/* db1 */
 #define DR_TRAP2	(0x4)		/* db2 */
diff --git a/trunk/arch/x86/kernel/traps.c b/trunk/arch/x86/kernel/traps.c
index 33399176512a..1168e4454188 100644
--- a/trunk/arch/x86/kernel/traps.c
+++ b/trunk/arch/x86/kernel/traps.c
@@ -534,6 +534,9 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
 
 	get_debugreg(dr6, 6);
 
+	/* Filter out all the reserved bits which are preset to 1 */
+	dr6 &= ~DR6_RESERVED;
+
 	/* Catch kmemcheck conditions first of all! */
 	if ((dr6 & DR_STEP) && kmemcheck_trap(regs))
 		return;