Re: [PATCH v3] linux-user: Adjust child_tidptr on set_tid_address() syscall

[Laurent Vivier <laurent@vivier.eu>]

Le 28/05/2022 à 12:52, Helge Deller a écrit :
> Keep track of the new child tidptr given by a set_tid_address() syscall.
> 
> Do not call the host set_tid_address() syscall because we are emulating
> the behaviour of writing to child_tidptr in the exit() path.
> 
> Signed-off-by: Helge Deller<deller@gmx.de>
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> 
> --
> v3:
> - Respin of the patch because the v2 version was mungled in-between the
>    mail of the v1 version. Now it's possible to get correct patch with b4
> - Rephrased commit message
> - Added Richard's Reviewed-by
> v2:
> - was mungled in v1 mail thread
> 
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index f55cdebee5..1166e9f014 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -320,9 +320,6 @@ _syscall3(int,sys_syslog,int,type,char*,bufp,int,len)
>   #ifdef __NR_exit_group
>   _syscall1(int,exit_group,int,error_code)
>   #endif
> -#if defined(TARGET_NR_set_tid_address) && defined(__NR_set_tid_address)
> -_syscall1(int,set_tid_address,int *,tidptr)
> -#endif
>   #if defined(__NR_futex)
>   _syscall6(int,sys_futex,int *,uaddr,int,op,int,val,
>             const struct timespec *,timeout,int *,uaddr2,int,val3)
> @@ -12200,9 +12197,14 @@ static abi_long do_syscall1(CPUArchState *cpu_env, int num, abi_long arg1,
>       }
>   #endif
> 
> -#if defined(TARGET_NR_set_tid_address) && defined(__NR_set_tid_address)
> +#if defined(TARGET_NR_set_tid_address)
>       case TARGET_NR_set_tid_address:
> -        return get_errno(set_tid_address((int *)g2h(cpu, arg1)));
> +    {
> +        TaskState *ts = cpu->opaque;
> +        ts->child_tidptr = arg1;
> +        /* do not call host set_tid_address() syscall, instead return tid() */
> +        return get_errno(sys_gettid());
> +    }
>   #endif
> 
>       case TARGET_NR_tkill:
> 

Reviewed-by: Laurent Vivier <laurent@vivier.eu>