Re: [Qemu-devel] [PATCH v3 14/18] target/s390x: Tidy SRST

[Aurelien Jarno]

On 2017-06-19 17:04, Richard Henderson wrote:
> Since we require all registers saved on input, read R0 from ENV instead
> of passing it manually.  Recognize the specification exception when R0
> contains incorrect data.
> 
> Signed-off-by: Richard Henderson <address@hidden>
> ---
>  target/s390x/helper.h     |  2 +-
>  target/s390x/mem_helper.c | 11 ++++++++---
>  target/s390x/translate.c  |  2 +-
>  3 files changed, 10 insertions(+), 5 deletions(-)
> 
> diff --git a/target/s390x/helper.h b/target/s390x/helper.h
> index c014820..cd51b89 100644
> --- a/target/s390x/helper.h
> +++ b/target/s390x/helper.h
> @@ -12,7 +12,7 @@ DEF_HELPER_FLAGS_3(divs32, TCG_CALL_NO_WG, s64, env, s64, 
> s64)
>  DEF_HELPER_FLAGS_3(divu32, TCG_CALL_NO_WG, i64, env, i64, i64)
>  DEF_HELPER_FLAGS_3(divs64, TCG_CALL_NO_WG, s64, env, s64, s64)
>  DEF_HELPER_FLAGS_4(divu64, TCG_CALL_NO_WG, i64, env, i64, i64, i64)
> -DEF_HELPER_4(srst, i64, env, i64, i64, i64)
> +DEF_HELPER_3(srst, i64, env, i64, i64)
>  DEF_HELPER_4(clst, i64, env, i64, i64, i64)
>  DEF_HELPER_FLAGS_4(mvn, TCG_CALL_NO_WG, void, env, i32, i64, i64)
>  DEF_HELPER_FLAGS_4(mvo, TCG_CALL_NO_WG, void, env, i32, i64, i64)
> diff --git a/target/s390x/mem_helper.c b/target/s390x/mem_helper.c
> index df082f5..990858e 100644
> --- a/target/s390x/mem_helper.c
> +++ b/target/s390x/mem_helper.c
> @@ -538,12 +538,17 @@ static inline void set_length(CPUS390XState *env, int 
> reg, uint64_t length)
>  }
>  
>  /* search string (c is byte to search, r2 is string, r1 end of string) */
> -uint64_t HELPER(srst)(CPUS390XState *env, uint64_t r0, uint64_t end,
> -                      uint64_t str)
> +uint64_t HELPER(srst)(CPUS390XState *env, uint64_t end, uint64_t str)
>  {
>      uintptr_t ra = GETPC();
>      uint32_t len;
> -    uint8_t v, c = r0;
> +    uint8_t v, c = env->regs[0];
> +
> +    /* Bits 32-55 must contain all 0.  */
> +    if (env->regs[0] & 0xffffff00u) {
> +        cpu_restore_state(ENV_GET_CPU(env), ra);
> +        program_interrupt(env, PGM_SPECIFICATION, 6);
> +    }
>  
>      str = wrap_address(env, str);
>      end = wrap_address(env, end);
> diff --git a/target/s390x/translate.c b/target/s390x/translate.c
> index f8989ec..4a860f1 100644
> --- a/target/s390x/translate.c
> +++ b/target/s390x/translate.c
> @@ -4256,7 +4256,7 @@ static ExitStatus op_stpq(DisasContext *s, DisasOps *o)
>  
>  static ExitStatus op_srst(DisasContext *s, DisasOps *o)
>  {
> -    gen_helper_srst(o->in1, cpu_env, regs[0], o->in1, o->in2);
> +    gen_helper_srst(o->in1, cpu_env, o->in1, o->in2);
>      set_cc_static(s);
>      return_low128(o->in2);
>      return NO_EXIT;

The cleanup is a good step, but I guess that should also be the moment
to improve the address masking/wrapping (see comment on next patch).

Anyway:

Reviewed-by: Aurelien Jarno <address@hidden>

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
address@hidden                 http://www.aurel32.net