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Re: [Qemu-devel] [PATCH] target-arm: Fix arm_debug_excp_handler() for si
From: |
Sergey Fedorov |
Subject: |
Re: [Qemu-devel] [PATCH] target-arm: Fix arm_debug_excp_handler() for singlestep enabled |
Date: |
Tue, 3 Nov 2015 12:02:22 +0300 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 |
On 02.11.2015 21:28, Peter Maydell wrote:
> On 2 November 2015 at 17:51, Sergey Fedorov <address@hidden> wrote:
>> CPU singlestep is done by generating a debug internal exception. Do not
>> raise a real CPU exception in case of singlestepping.
>>
>> Signed-off-by: Sergey Fedorov <address@hidden>
>> ---
>> target-arm/op_helper.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/target-arm/op_helper.c b/target-arm/op_helper.c
>> index 7929c71..67d9ffb 100644
>> --- a/target-arm/op_helper.c
>> +++ b/target-arm/op_helper.c
>> @@ -909,7 +909,7 @@ 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)) {
>> + if (cs->singlestep_enabled || cpu_breakpoint_test(cs, pc, BP_GDB)) {
>> return;
>> }
> So I think this will mean that if we're gdbstub-single-stepping then
> an architectural breakpoint on the insn we're stepping won't fire.
>
> Does using a test
>
> if (!cpu_breakpoint_test(cs, pc, BP_CPU)) {
> return;
> }
>
> fix the singlestep bug too? If so I think it would probably be
> preferable.
Actually, it is supposed that gdbstub breakpoints should be handled
before CPU breakpoints. So I think we should rather do this way:
if (cpu_breakpoint_test(cs, pc, BP_GDB) || !cpu_breakpoint_test(cs, pc,
BP_CPU)) {
return;
}
Thanks,
Sergey