diff options
| author | K.Prasad <prasad@linux.vnet.ibm.com> | 2009-06-01 20:17:06 +0200 |
|---|---|---|
| committer | Frederic Weisbecker <fweisbec@gmail.com> | 2009-06-02 22:47:00 +0200 |
| commit | 62edab9056a6cf0c9207339c8892c923a5217e45 (patch) | |
| tree | 2becd775fdc2a25df3daacf69d80685b251fbed9 /arch/x86/kernel/hw_breakpoint.c | |
| parent | hw-breakpoints: ftrace plugin for kernel symbol tracing using HW Breakpoint i... (diff) | |
| download | linux-62edab9056a6cf0c9207339c8892c923a5217e45.tar.xz linux-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/hw_breakpoint.c')
| -rw-r--r-- | arch/x86/kernel/hw_breakpoint.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoint.c index 4867c9f3b5fb..69451473dbd2 100644 --- a/arch/x86/kernel/hw_breakpoint.c +++ b/arch/x86/kernel/hw_breakpoint.c @@ -314,8 +314,12 @@ int __kprobes hw_breakpoint_handler(struct die_args *args) { int i, cpu, rc = NOTIFY_STOP; struct hw_breakpoint *bp; - /* The DR6 value is stored in args->err */ - unsigned long dr7, dr6 = args->err; + unsigned long dr7, dr6; + unsigned long *dr6_p; + + /* The DR6 value is pointed by args->err */ + dr6_p = (unsigned long *)ERR_PTR(args->err); + dr6 = *dr6_p; /* Do an early return if no trap bits are set in DR6 */ if ((dr6 & DR_TRAP_BITS) == 0) @@ -352,6 +356,11 @@ int __kprobes hw_breakpoint_handler(struct die_args *args) rc = NOTIFY_DONE; } /* + * Reset the 'i'th TRAP bit in dr6 to denote completion of + * exception handling + */ + (*dr6_p) &= ~(DR_TRAP0 << i); + /* * bp can be NULL due to lazy debug register switching * or due to the delay between updates of hbp_kernel_pos * and this_hbp_kernel. |