[Qemu-devel] [PATCH v2] target-arm: Fix non-CPU breakpoint handling in arm_debug_excp_handler()

[Sergey Fedorov <serge.fdrv@gmail.com>]

Do not raise a CPU exception if no CPU breakpoint has fired, since
singlestep is also done by generating a debug internal exception. This
fixes a bug with singlestepping in gdbstub.

Signed-off-by: Sergey Fedorov <serge.fdrv@gmail.com>
---
This is a v2 of 'target-arm: Fix arm_debug_excp_handler() for singlestep
enabled.'

Changes in v2:
 * Commit subject and body changed
 * Instead of checking for singlestep enabled, CPU breakpoint match checked

 target-arm/op_helper.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/target-arm/op_helper.c b/target-arm/op_helper.c
index b5db345..6cd54c8 100644
--- a/target-arm/op_helper.c
+++ b/target-arm/op_helper.c
@@ -917,7 +917,13 @@ void arm_debug_excp_handler(CPUState *cs)
         uint64_t pc = is_a64(env) ? env->pc : env->regs[15];
         bool same_el = (arm_debug_target_el(env) == arm_current_el(env));
 
-        if (cpu_breakpoint_test(cs, pc, BP_GDB)) {
+        /* (1) GDB breakpoints should be handled first.
+         * (2) Do not raise a CPU exception if no CPU breakpoint has fired,
+         * since singlestep is also done by generating a debug internal
+         * exception.
+         */
+        if (cpu_breakpoint_test(cs, pc, BP_GDB)
+            || !cpu_breakpoint_test(cs, pc, BP_CPU)) {
             return;
         }
 
-- 
1.9.1