Re: [Qemu-devel] [PATCHv2] linux-user: Add getcpu() support

[Laurent Vivier]

Le 11/01/2018 à 01:17, Samuel Thibault a écrit :
> Signed-off-by: Samuel Thibault <address@hidden>
> 
> ---
> Difference from v1: handle failure of put_user_u32 with goto efault;
> ---
>  linux-user/syscall.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 11c9116c4a..89d78b7b48 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -296,6 +296,8 @@ _syscall3(int, sys_sched_getaffinity, pid_t, pid, 
> unsigned int, len,
>  #define __NR_sys_sched_setaffinity __NR_sched_setaffinity
>  _syscall3(int, sys_sched_setaffinity, pid_t, pid, unsigned int, len,
>            unsigned long *, user_mask_ptr);
> +#define __NR_sys_getcpu __NR_getcpu
> +_syscall3(int, sys_getcpu, unsigned *, cpu, unsigned *, node, void *, 
> tcache);
>  _syscall4(int, reboot, int, magic1, int, magic2, unsigned int, cmd,
>            void *, arg);
>  _syscall2(int, capget, struct __user_cap_header_struct *, header,
> @@ -10403,6 +10405,20 @@ abi_long do_syscall(void *cpu_env, int num, abi_long 
> arg1,
>              ret = get_errno(sys_sched_setaffinity(arg1, mask_size, mask));
>          }
>          break;
> +    case TARGET_NR_getcpu:
> +        {
> +            unsigned cpu, node;
> +            ret = get_errno(sys_getcpu(arg1 ? &cpu : NULL,
> +                                       arg2 ? &node : NULL,
> +                                       NULL));

you must check for return status to avoid setting the values if there is
an error:

           if (!is_error(ret)) {

> +            if (arg1 && put_user_u32(cpu, arg1)) {
> +                goto efault;
> +            }
> +            if (arg2 && put_user_u32(node, arg2)) {
> +                goto efault;
> +            }

           }

> +        }
> +        break;
>      case TARGET_NR_sched_setparam:
>          {
>              struct sched_param *target_schp;
> 

Thanks,
Laurent