In this portion of the patch we hook up the watch trap handler. When the
trap occurs, we copy the register contents into the thread_struct and
send SIGTRAP. If the current thread was not expecting the trap, the
watch register values must have been left over from a different context and
we just clear the registers and return.
Also I turn off the message the prints on each trap, as these traps are now
expected.
Signed-off-by: David Daney <ddaney@xxxxxxxxxx>
---
arch/mips/kernel/genex.S | 4 ++++
arch/mips/kernel/traps.c | 13 +++++++++++++
2 files changed, 17 insertions(+), 0 deletions(-)
diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S
index c6ada98..15a9bde 100644
--- a/arch/mips/kernel/genex.S
+++ b/arch/mips/kernel/genex.S
@@ -416,7 +416,11 @@ NESTED(nmi_handler, PT_SIZE, sp)
BUILD_HANDLER tr tr sti silent /* #13 */
BUILD_HANDLER fpe fpe fpe silent /* #15 */
BUILD_HANDLER mdmx mdmx sti silent /* #22 */
+#ifdef CONFIG_HARDWARE_WATCHPOINTS
+ BUILD_HANDLER watch watch sti silent /* #23 */
+#else
BUILD_HANDLER watch watch sti verbose /* #23 */
+#endif
BUILD_HANDLER mcheck mcheck cli verbose /* #24 */
BUILD_HANDLER mt mt sti silent /* #25 */
BUILD_HANDLER dsp dsp sti silent /* #26 */
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 984c0d0..6a5f3f0 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -887,6 +887,18 @@ asmlinkage void do_mdmx(struct pt_regs *regs)
asmlinkage void do_watch(struct pt_regs *regs)
{
+#ifdef CONFIG_HARDWARE_WATCHPOINTS
+ /*
+ * If the current thread has the watch registers loaded, save
+ * their values and send SIGTRAP. Otherwise another thread
+ * left the registers set, clear them and continue.
+ */
+ if (test_tsk_thread_flag(current, TIF_LOAD_WATCH)) {
+ mips_read_watch_registers();
+ force_sig(SIGTRAP, current);
+ } else
+ mips_clear_watch_registers();
+#else
if (board_watchpoint_handler) {
(*board_watchpoint_handler)(regs);
return;
@@ -899,6 +911,7 @@ asmlinkage void do_watch(struct pt_regs *regs)
dump_tlb_all();
show_regs(regs);
panic("Caught WATCH exception - probably caused by stack overflow.");
+#endif
}
asmlinkage void do_mcheck(struct pt_regs *regs)
--
1.5.5
