Re: [PATCH v2 02/41] accel/tcg: Move clear_helper_retaddr to cpu loop

[Warner Losh]

> On Sep 18, 2021, at 12:44 PM, Richard Henderson 
> <richard.henderson@linaro.org> wrote:
> 
> Currently there are only two places that require we reset this
> value before exiting to the main loop, but that will change.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
> accel/tcg/cpu-exec.c  | 3 ++-
> accel/tcg/user-exec.c | 2 --
> 2 files changed, 2 insertions(+), 3 deletions(-)

Reviewed-by: Warner Losh <imp@bsdimp.com>

> diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
> index 5fd1ed3422..410588d08a 100644
> --- a/accel/tcg/cpu-exec.c
> +++ b/accel/tcg/cpu-exec.c
> @@ -451,6 +451,7 @@ void cpu_exec_step_atomic(CPUState *cpu)
>          * memory.
>          */
> #ifndef CONFIG_SOFTMMU
> +        clear_helper_retaddr();
>         tcg_debug_assert(!have_mmap_lock());
> #endif
>         if (qemu_mutex_iothread_locked()) {
> @@ -460,7 +461,6 @@ void cpu_exec_step_atomic(CPUState *cpu)
>         qemu_plugin_disable_mem_helpers(cpu);
>     }
> 
> -
>     /*
>      * As we start the exclusive region before codegen we must still
>      * be in the region if we longjump out of either the codegen or
> @@ -905,6 +905,7 @@ int cpu_exec(CPUState *cpu)
> #endif
> 
> #ifndef CONFIG_SOFTMMU
> +        clear_helper_retaddr();
>         tcg_debug_assert(!have_mmap_lock());
> #endif
>         if (qemu_mutex_iothread_locked()) {
> diff --git a/accel/tcg/user-exec.c b/accel/tcg/user-exec.c
> index cef025d001..e94f1fed00 100644
> --- a/accel/tcg/user-exec.c
> +++ b/accel/tcg/user-exec.c
> @@ -175,7 +175,6 @@ static inline int handle_cpu_signal(uintptr_t pc, 
> siginfo_t *info,
>              * currently executing TB was modified and must be exited
>              * immediately.  Clear helper_retaddr for next execution.
>              */
> -            clear_helper_retaddr();
>             cpu_exit_tb_from_sighandler(cpu, old_set);
>             /* NORETURN */
> 
> @@ -193,7 +192,6 @@ static inline int handle_cpu_signal(uintptr_t pc, 
> siginfo_t *info,
>      * an exception.  Undo signal and retaddr state prior to longjmp.
>      */
>     sigprocmask(SIG_SETMASK, old_set, NULL);
> -    clear_helper_retaddr();
> 
>     cc = CPU_GET_CLASS(cpu);
>     cc->tcg_ops->tlb_fill(cpu, address, 0, access_type,
> -- 
> 2.25.1
> 
>