Re: [PATCH v3 03/33] target/alpha: Fix SWCR_TRAP_ENABLE_MASK

[Philippe Mathieu-Daudé]

On 9/24/19 11:00 PM, Alex Bennée wrote:
> From: Richard Henderson <address@hidden>
> 
> The CONFIG_USER_ONLY adjustment blindly mashed the swcr
> exception enable bits into the fpcr exception disable bits.
> 
> However, fpcr_exc_enable has already converted the exception
> disable bits into the exception status bits in order to make
> it easier to mask status bits at runtime.
> 
> Instead, merge the swcr enable bits with the fpcr before we
> convert to status bits.
> 
> Signed-off-by: Richard Henderson <address@hidden>
> Signed-off-by: Alex Bennée <address@hidden>
> Message-Id: <address@hidden>

Reviewed-by: Philippe Mathieu-Daudé <address@hidden>

> ---
>  target/alpha/helper.c | 23 ++++++++++++++---------
>  1 file changed, 14 insertions(+), 9 deletions(-)
> 
> diff --git a/target/alpha/helper.c b/target/alpha/helper.c
> index 10602fb3394..e21c488aa32 100644
> --- a/target/alpha/helper.c
> +++ b/target/alpha/helper.c
> @@ -46,34 +46,39 @@ void cpu_alpha_store_fpcr(CPUAlphaState *env, uint64_t 
> val)
>      uint32_t fpcr = val >> 32;
>      uint32_t t = 0;
>  
> +    /* Record the raw value before adjusting for linux-user.  */
> +    env->fpcr = fpcr;
> +
> +#ifdef CONFIG_USER_ONLY
> +    /*
> +     * Override some of these bits with the contents of ENV->SWCR.
> +     * In system mode, some of these would trap to the kernel, at
> +     * which point the kernel's handler would emulate and apply
> +     * the software exception mask.
> +     */
> +    uint32_t soft_fpcr = alpha_ieee_swcr_to_fpcr(env->swcr) >> 32;
> +    fpcr |= soft_fpcr & FPCR_STATUS_MASK;
> +#endif
> +
>      t |= CONVERT_BIT(fpcr, FPCR_INED, FPCR_INE);
>      t |= CONVERT_BIT(fpcr, FPCR_UNFD, FPCR_UNF);
>      t |= CONVERT_BIT(fpcr, FPCR_OVFD, FPCR_OVF);
>      t |= CONVERT_BIT(fpcr, FPCR_DZED, FPCR_DZE);
>      t |= CONVERT_BIT(fpcr, FPCR_INVD, FPCR_INV);
>  
> -    env->fpcr = fpcr;
>      env->fpcr_exc_enable = ~t & FPCR_STATUS_MASK;
>  
>      env->fpcr_dyn_round = rm_map[(fpcr & FPCR_DYN_MASK) >> FPCR_DYN_SHIFT];
>  
>      env->fpcr_flush_to_zero = (fpcr & FPCR_UNFD) && (fpcr & FPCR_UNDZ);
>      env->fp_status.flush_inputs_to_zero = (fpcr & FPCR_DNZ) != 0;
> -
>  #ifdef CONFIG_USER_ONLY
> -    /*
> -     * Override some of these bits with the contents of ENV->SWCR.
> -     * In system mode, some of these would trap to the kernel, at
> -     * which point the kernel's handler would emulate and apply
> -     * the software exception mask.
> -     */
>      if (env->swcr & SWCR_MAP_DMZ) {
>          env->fp_status.flush_inputs_to_zero = 1;
>      }
>      if (env->swcr & SWCR_MAP_UMZ) {
>          env->fpcr_flush_to_zero = 1;
>      }
> -    env->fpcr_exc_enable &= ~(alpha_ieee_swcr_to_fpcr(env->swcr) >> 32);
>  #endif
>  }
>  
>