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authorK.Prasad <prasad@linux.vnet.ibm.com>2009-06-01 23:47:06 +0530
committerFrederic Weisbecker <fweisbec@gmail.com>2009-06-02 22:47:00 +0200
commit62edab9056a6cf0c9207339c8892c923a5217e45 (patch)
tree2becd775fdc2a25df3daacf69d80685b251fbed9 /arch/x86/kernel/kprobes.c
parenthw-breakpoints: ftrace plugin for kernel symbol tracing using HW Breakpoint interfaces (diff)
downloadlinux-dev-62edab9056a6cf0c9207339c8892c923a5217e45.tar.xz
linux-dev-62edab9056a6cf0c9207339c8892c923a5217e45.zip
hw-breakpoints: reset bits in dr6 after the corresponding exception is handled
This patch resets the bit in dr6 after the corresponding exception is handled in code, so that we keep a clean track of the current virtual debug status register. [ Impact: keep track of breakpoints triggering completion ] Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Diffstat (limited to 'arch/x86/kernel/kprobes.c')
-rw-r--r--arch/x86/kernel/kprobes.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c
index 7b5169d2b000..b5b1848c5336 100644
--- a/arch/x86/kernel/kprobes.c
+++ b/arch/x86/kernel/kprobes.c
@@ -54,6 +54,7 @@
#include <asm/pgtable.h>
#include <asm/uaccess.h>
#include <asm/alternative.h>
+#include <asm/debugreg.h>
void jprobe_return_end(void);
@@ -967,8 +968,14 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
ret = NOTIFY_STOP;
break;
case DIE_DEBUG:
- if (post_kprobe_handler(args->regs))
+ if (post_kprobe_handler(args->regs)) {
+ /*
+ * Reset the BS bit in dr6 (pointed by args->err) to
+ * denote completion of processing
+ */
+ (*(unsigned long *)ERR_PTR(args->err)) &= ~DR_STEP;
ret = NOTIFY_STOP;
+ }
break;
case DIE_GPF:
/*