Re: [Qemu-devel] [RFC v6 08/14] target-arm: Add atomic_clear helper for CLREX insn

[Alex Bennée]

Alvise Rigo <address@hidden> writes:

> Add a simple helper function to emulate the CLREX instruction.

And now I see ;-)

I suspect this should be merged with the other helpers as a generic helper.

>
> Suggested-by: Jani Kokkonen <address@hidden>
> Suggested-by: Claudio Fontana <address@hidden>
> Signed-off-by: Alvise Rigo <address@hidden>
> ---
>  target-arm/helper.h    | 2 ++
>  target-arm/op_helper.c | 6 ++++++
>  target-arm/translate.c | 1 +
>  3 files changed, 9 insertions(+)
>
> diff --git a/target-arm/helper.h b/target-arm/helper.h
> index c2a85c7..37cec49 100644
> --- a/target-arm/helper.h
> +++ b/target-arm/helper.h
> @@ -532,6 +532,8 @@ DEF_HELPER_2(dc_zva, void, env, i64)
>  DEF_HELPER_FLAGS_2(neon_pmull_64_lo, TCG_CALL_NO_RWG_SE, i64, i64, i64)
>  DEF_HELPER_FLAGS_2(neon_pmull_64_hi, TCG_CALL_NO_RWG_SE, i64, i64, i64)
>
> +DEF_HELPER_1(atomic_clear, void, env)
> +
>  #ifdef TARGET_AARCH64
>  #include "helper-a64.h"
>  #endif
> diff --git a/target-arm/op_helper.c b/target-arm/op_helper.c
> index 6cd54c8..5a67557 100644
> --- a/target-arm/op_helper.c
> +++ b/target-arm/op_helper.c
> @@ -50,6 +50,12 @@ static int exception_target_el(CPUARMState *env)
>      return target_el;
>  }
>
> +void HELPER(atomic_clear)(CPUARMState *env)
> +{
> +    ENV_GET_CPU(env)->excl_protected_range.begin = -1;

Is there not a defined reset value EXCLUSIVE_RESET_ADDR we should use here?

> +    ENV_GET_CPU(env)->ll_sc_context = false;
> +}
> +
>  uint32_t HELPER(neon_tbl)(CPUARMState *env, uint32_t ireg, uint32_t def,
>                            uint32_t rn, uint32_t maxindex)
>  {
> diff --git a/target-arm/translate.c b/target-arm/translate.c
> index e88d8a3..e0362e0 100644
> --- a/target-arm/translate.c
> +++ b/target-arm/translate.c
> @@ -7514,6 +7514,7 @@ static void gen_load_exclusive(DisasContext *s, int rt, 
> int rt2,
>  static void gen_clrex(DisasContext *s)
>  {
>  #ifdef CONFIG_TCG_USE_LDST_EXCL
> +    gen_helper_atomic_clear(cpu_env);
>  #else
>      tcg_gen_movi_i64(cpu_exclusive_addr, -1);
>  #endif


--
Alex Bennée