[RFC Patch 7/9] Modify signal handling code to refrain fromre-enabling HW Breakpoints

[K.Prasad]

This patch disables re-enabling of Hardware Breakpoint registers through the 
signal handling code. This is now during hw_breakpoint_handler().

Signed-off-by: K.Prasad <prasad@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
---
 arch/x86/kernel/signal_32.c |    9 ---------
 arch/x86/kernel/signal_64.c |    8 --------
 2 files changed, 17 deletions(-)

Index: linux-bkpt-lkml-27-rc9/arch/x86/kernel/signal_32.c
===================================================================
--- linux-bkpt-lkml-27-rc9.orig/arch/x86/kernel/signal_32.c
+++ linux-bkpt-lkml-27-rc9/arch/x86/kernel/signal_32.c
@@ -600,15 +600,6 @@ static void do_signal(struct pt_regs *re
 
 	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 	if (signr > 0) {
-		/*
-		 * Re-enable any watchpoints before delivering the
-		 * signal to user space. The processor register will
-		 * have been cleared if the watchpoint triggered
-		 * inside the kernel.
-		 */
-		if (current->thread.debugreg7)
-			set_debugreg(current->thread.debugreg7, 7);
-
 		/* Whee! Actually deliver the signal.  */
 		if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 			/*
Index: linux-bkpt-lkml-27-rc9/arch/x86/kernel/signal_64.c
===================================================================
--- linux-bkpt-lkml-27-rc9.orig/arch/x86/kernel/signal_64.c
+++ linux-bkpt-lkml-27-rc9/arch/x86/kernel/signal_64.c
@@ -496,14 +496,6 @@ static void do_signal(struct pt_regs *re
 
 	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 	if (signr > 0) {
-		/* Re-enable any watchpoints before delivering the
-		 * signal to user space. The processor register will
-		 * have been cleared if the watchpoint triggered
-		 * inside the kernel.
-		 */
-		if (current->thread.debugreg7)
-			set_debugreg(current->thread.debugreg7, 7);
-
 		/* Whee!  Actually deliver the signal.  */
 		if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 			/*
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/