lkml.org 
[lkml]   [2010]   [Jan]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[Patch 1/2 v2] Clear reserved bits of DR6 in do_debug()
Clear the reserved bits from the stored copy of debug status register (DR6).
This will help easy bitwise operations.

Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
---
arch/x86/include/asm/debugreg.h | 3 +++
arch/x86/kernel/traps.c | 3 +++
2 files changed, 6 insertions(+)
Index: linux-2.6-tip.bugfix_perf_hbkpt/arch/x86/include/asm/debugreg.h
===================================================================
--- linux-2.6-tip.bugfix_perf_hbkpt.orig/arch/x86/include/asm/debugreg.h
+++ linux-2.6-tip.bugfix_perf_hbkpt/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 */
Index: linux-2.6-tip.bugfix_perf_hbkpt/arch/x86/kernel/traps.c
===================================================================
--- linux-2.6-tip.bugfix_perf_hbkpt.orig/arch/x86/kernel/traps.c
+++ linux-2.6-tip.bugfix_perf_hbkpt/arch/x86/kernel/traps.c
@@ -534,6 +534,9 @@ dotraplinkage void __kprobes do_debug(st

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;


\
 
 \ /
  Last update: 2010-01-28 12:17    [from the cache]
©2003-2011 Jasper Spaans