From: Jan Beulich <jbeulich@novell.com>
Date: Sat, 25 Mar 2006 15:29:19 +0000 (+0100)
Subject: [PATCH] x86_64: disallow multi-byte hardware execution breakpoints
X-Git-Tag: v2.6.17-rc1~722
X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=893efca9279d7a78bae6532de0524e53370819d5;p=linux-2.6-omap-h63xx.git

[PATCH] x86_64: disallow multi-byte hardware execution breakpoints

While AMD formally permits multi-byte execution breakpoints, Intel
disallows 8-byte as much as 2- or 4-byte ones.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/arch/x86_64/kernel/ptrace.c b/arch/x86_64/kernel/ptrace.c
index 53205622351..d44b2c1e63a 100644
--- a/arch/x86_64/kernel/ptrace.c
+++ b/arch/x86_64/kernel/ptrace.c
@@ -420,9 +420,9 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 		case offsetof(struct user, u_debugreg[7]):
 			/* See arch/i386/kernel/ptrace.c for an explanation of
 			 * this awkward check.*/
-				  data &= ~DR_CONTROL_RESERVED;
-				  for(i=0; i<4; i++)
-					  if ((0x5454 >> ((data >> (16 + 4*i)) & 0xf)) & 1)
+			data &= ~DR_CONTROL_RESERVED;
+			for(i=0; i<4; i++)
+				if ((0x5554 >> ((data >> (16 + 4*i)) & 0xf)) & 1)
 					break;
 			if (i == 4) {
 				child->thread.debugreg7 = data;