Re: [PATCH] linux-user: signal: Support TARGET_SS_AUTODISARM

[Laurent Vivier]

Le 08/10/2020 à 06:25, chengang@emindsoft.com.cn a écrit :
> From: Chen Gang <chengang@emindsoft.com.cn>
> 
> Microsoft sqlserver 2017 x86_64 uses it. The implementation references
> from the linux kernel.
> 
> Signed-off-by: Chen Gang <chengang@emindsoft.com.cn>
> ---
>  linux-user/generic/signal.h |  6 ++++++
>  linux-user/signal.c         | 23 ++++++++++++++++++-----
>  2 files changed, 24 insertions(+), 5 deletions(-)
> 
> diff --git a/linux-user/generic/signal.h b/linux-user/generic/signal.h
> index e1083f8fba..943bc1a1e2 100644
> --- a/linux-user/generic/signal.h
> +++ b/linux-user/generic/signal.h
> @@ -54,4 +54,10 @@
>  #define TARGET_SIG_BLOCK          0    /* for blocking signals */
>  #define TARGET_SIG_UNBLOCK        1    /* for unblocking signals */
>  #define TARGET_SIG_SETMASK        2    /* for setting the signal mask */
> +
> +/* bit-flags */
> +#define TARGET_SS_AUTODISARM (1U << 31) /* disable sas during sighandling */
> +/* mask for all SS_xxx flags */
> +#define TARGET_SS_FLAG_BITS  TARGET_SS_AUTODISARM
> +
>  #endif

This part should be moved to the other patch:

  linux-user: target: signal: Support TARGET_SS_AUTODISARM

> diff --git a/linux-user/signal.c b/linux-user/signal.c
> index 8cf51ffecd..b5f04ae160 100644
> --- a/linux-user/signal.c
> +++ b/linux-user/signal.c
> @@ -263,6 +263,10 @@ int on_sig_stack(unsigned long sp)
>  {
>      TaskState *ts = (TaskState *)thread_cpu->opaque;
>  
> +    if (ts->sigaltstack_used.ss_flags & TARGET_SS_AUTODISARM) {
> +        return 0;
> +    }
> +
>      return (sp - ts->sigaltstack_used.ss_sp
>              < ts->sigaltstack_used.ss_size);
>  }
> @@ -293,8 +297,13 @@ void target_save_altstack(target_stack_t *uss, 
> CPUArchState *env)
>      TaskState *ts = (TaskState *)thread_cpu->opaque;
>  
>      __put_user(ts->sigaltstack_used.ss_sp, &uss->ss_sp);
> -    __put_user(sas_ss_flags(get_sp_from_cpustate(env)), &uss->ss_flags);
> +    __put_user(ts->sigaltstack_used.ss_flags, &uss->ss_flags);

Could you explain why you remove sas_ss_flags() and get_sp_from_cpustate(env)?

>      __put_user(ts->sigaltstack_used.ss_size, &uss->ss_size);
> +    if (ts->sigaltstack_used.ss_flags & TARGET_SS_AUTODISARM) {
> +        ts->sigaltstack_used.ss_sp = 0;
> +        ts->sigaltstack_used.ss_size = 0;
> +        ts->sigaltstack_used.ss_flags = TARGET_SS_DISABLE;
> +    }
>  }
>  
>  /* siginfo conversion */
> @@ -768,7 +777,7 @@ abi_long do_sigaltstack(abi_ulong uss_addr, abi_ulong 
> uoss_addr, abi_ulong sp)
>      {
>          __put_user(ts->sigaltstack_used.ss_sp, &oss.ss_sp);
>          __put_user(ts->sigaltstack_used.ss_size, &oss.ss_size);
> -        __put_user(sas_ss_flags(sp), &oss.ss_flags);
> +        __put_user(ts->sigaltstack_used.ss_flags, &oss.ss_flags);

Ditto

Thanks,
Laurent