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

[Laurent Vivier <laurent@vivier.eu>]

Le 28/12/2017 à 16:00, Samuel Thibault a écrit :
> Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
> ---
>  linux-user/syscall.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 8ec7de96ce..bb8cb726f5 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,
> @@ -10443,6 +10445,20 @@ 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));
> +            if (arg1) {
> +                put_user(cpu, arg1, abi_uint);
> +            }
> +            if (arg2) {
> +                put_user(node, arg2, abi_uint);
> +            }

You must check for EFAULT.

    if (arg1 && put_user_u32(cpu, arg1)) {
        goto efault;
    }
...

I don't think you need to use the abi_uint type as we are using
put_user_u32() for all the other syscalls for unsigned int.

Thanks,
Laurent