From: "K.Prasad" <prasad@linux.vnet.ibm.com>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>,
Frederic Weisbecker <fweisbec@gmail.com>,
Roland McGrath <roland@redhat.com>,
Alan Stern <stern@rowland.harvard.edu>,
Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
Pekka Enberg <penberg@cs.helsinki.fi>,
Vegard Nossum <vegardno@ifi.uio.no>,
Oleg Nesterov <oleg@redhat.com>
Subject: [RFC Patch 1/2][Bugfix][x86][hw-breakpoint] Clear reserved bits of DR6 in do_debug()
Date: Sat, 26 Dec 2009 23:57:25 +0530 [thread overview]
Message-ID: <20091226182725.GB9494@in.ibm.com> (raw)
In-Reply-To: 20091226175533.149765731@linux.vnet.ibm.com
[-- Attachment #1: fix_dr6_reserved_01 --]
[-- Type: text/plain, Size: 1362 bytes --]
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/arch/x86/include/asm/debugreg.h
===================================================================
--- linux-2.6-tip.orig/arch/x86/include/asm/debugreg.h
+++ linux-2.6-tip/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/arch/x86/kernel/traps.c
===================================================================
--- linux-2.6-tip.orig/arch/x86/kernel/traps.c
+++ linux-2.6-tip/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;
next parent reply other threads:[~2009-12-26 18:27 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20091226175533.149765731@linux.vnet.ibm.com>
2009-12-26 18:27 ` K.Prasad [this message]
2009-12-30 23:45 ` [RFC Patch 1/2][Bugfix][x86][hw-breakpoint] Clear reserved bits of DR6 in do_debug() Frederic Weisbecker
2009-12-31 18:49 ` K.Prasad
2010-01-10 3:22 ` Frederic Weisbecker
2009-12-26 18:28 ` [RFC Patch 2/2][Bugfix][x86][hw-breakpoint] Fix return-code to notifier chain in hw_breakpoint_handler K.Prasad
2009-12-31 0:33 ` Frederic Weisbecker
2009-12-31 0:38 ` Frederic Weisbecker
2009-12-31 19:02 ` K.Prasad
2010-01-10 3:18 ` Frederic Weisbecker
2010-01-11 19:15 ` Jan Kiszka
2010-01-16 19:41 ` K.Prasad
2010-01-20 6:01 ` K.Prasad
2010-01-22 9:14 ` Jan Kiszka
2010-01-22 9:21 ` K.Prasad
2010-01-25 22:21 ` Frederic Weisbecker
2010-01-27 10:29 ` K.Prasad
2009-12-31 0:44 ` Frederic Weisbecker
2010-01-25 22:11 ` Frederic Weisbecker
2010-01-27 10:28 ` K.Prasad
2010-01-27 16:11 ` Frederic Weisbecker
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