diff mbox series

target/arm: Don't read r4 from v8M exception stackframe twice

Message ID 20181002150304.2287-1-peter.maydell@linaro.org
State Superseded
Headers show
Series target/arm: Don't read r4 from v8M exception stackframe twice | expand

Commit Message

Peter Maydell Oct. 2, 2018, 3:03 p.m. UTC
A cut-and-paste error meant we were reading r4 from the v8M
callee-saves exception stack frame twice. This is harmless
since it just meant we did two memory accesses to the same
location, but it's unnecessary. Delete it.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

---
 target/arm/helper.c | 1 -
 1 file changed, 1 deletion(-)

-- 
2.19.0

Comments

Philippe Mathieu-Daudé Oct. 2, 2018, 3:14 p.m. UTC | #1
On 02/10/2018 17:03, Peter Maydell wrote:
> A cut-and-paste error meant we were reading r4 from the v8M

> callee-saves exception stack frame twice. This is harmless

> since it just meant we did two memory accesses to the same

> location, but it's unnecessary. Delete it.

> 

> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>


Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>


> ---

>  target/arm/helper.c | 1 -

>  1 file changed, 1 deletion(-)

> 

> diff --git a/target/arm/helper.c b/target/arm/helper.c

> index 073fb3c5cb0..5e721a65272 100644

> --- a/target/arm/helper.c

> +++ b/target/arm/helper.c

> @@ -7303,7 +7303,6 @@ static void do_v7m_exception_exit(ARMCPU *cpu)

>              }

>  

>              pop_ok = pop_ok &&

> -                v7m_stack_read(cpu, &env->regs[4], frameptr + 0x8, mmu_idx) &&

>                  v7m_stack_read(cpu, &env->regs[4], frameptr + 0x8, mmu_idx) &&

>                  v7m_stack_read(cpu, &env->regs[5], frameptr + 0xc, mmu_idx) &&

>                  v7m_stack_read(cpu, &env->regs[6], frameptr + 0x10, mmu_idx) &&

>
Richard Henderson Oct. 3, 2018, 7:47 p.m. UTC | #2
On 10/2/18 10:03 AM, Peter Maydell wrote:
> A cut-and-paste error meant we were reading r4 from the v8M

> callee-saves exception stack frame twice. This is harmless

> since it just meant we did two memory accesses to the same

> location, but it's unnecessary. Delete it.

> 

> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

> ---

>  target/arm/helper.c | 1 -

>  1 file changed, 1 deletion(-)


Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~
diff mbox series

Patch

diff --git a/target/arm/helper.c b/target/arm/helper.c
index 073fb3c5cb0..5e721a65272 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -7303,7 +7303,6 @@  static void do_v7m_exception_exit(ARMCPU *cpu)
             }
 
             pop_ok = pop_ok &&
-                v7m_stack_read(cpu, &env->regs[4], frameptr + 0x8, mmu_idx) &&
                 v7m_stack_read(cpu, &env->regs[4], frameptr + 0x8, mmu_idx) &&
                 v7m_stack_read(cpu, &env->regs[5], frameptr + 0xc, mmu_idx) &&
                 v7m_stack_read(cpu, &env->regs[6], frameptr + 0x10, mmu_idx) &&