Le 12/03/2020 à 23:13, Alistair Francis a écrit :
> Add support for host and target futex_time64. If futex_time64 exists on
> the host we try that first before falling back to the standard futux
> syscall.
>
> Signed-off-by: Alistair Francis <alistair.fran...@wdc.com>
> ---
> linux-user/syscall.c | 144 +++++++++++++++++++++++++++++++++++++++----
> 1 file changed, 131 insertions(+), 13 deletions(-)
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 60fd775d9c..9ae7a05e38 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
...
> @@ -6890,6 +6905,55 @@ static inline abi_long host_to_target_statx(struct
> target_statx *host_stx,
> }
> #endif
>
> +static int do_sys_futex(int *uaddr, int op, int val,
> + const struct timespec *timeout, int *uaddr2,
> + int val3)
> +{
> +#if HOST_LONG_BITS == 64
> +#if defined(__NR_futex)
> + /* always a 64-bit time_t, it doesn't define _time64 version */
> + return sys_futex(uaddr, op, val, timeout, uaddr2, val3);
> +
> +#endif
> +#else /* HOST_LONG_BITS == 64 */
> +#if defined(__NR_futex_time64)
> + if (sizeof(timeout->tv_sec) == 8) {
> + /* _time64 function on 32bit arch */
> + return sys_futex_time64(uaddr, op, val, timeout, uaddr2, val3);
> + }
> +#endif
> +#if defined(__NR_futex)
> + /* old function on 32bit arch */
> + return sys_futex(uaddr, op, val, timeout, uaddr2, val3);
> +#endif
> +#endif /* HOST_LONG_BITS == 64 */
> + return -TARGET_ENOSYS;
You cannot return -TARGET_ENOSYS because return value is supposed to be
a host value as you have direct value from sys_futex().
...
> @@ -7505,7 +7619,7 @@ static abi_long do_syscall1(void *cpu_env, int num,
> abi_long arg1,
> ts = cpu->opaque;
> if (ts->child_tidptr) {
> put_user_u32(0, ts->child_tidptr);
> - sys_futex(g2h(ts->child_tidptr), FUTEX_WAKE, INT_MAX,
> + do_sys_futex(g2h(ts->child_tidptr), FUTEX_WAKE, INT_MAX,
> NULL, NULL, 0);
And return value is ignored. Anyway at this point we can't do anything
if it doesn't work, but it should not happen. So I think the best to do
is to add a g_assert_not_reached() in place of "return -TARGET_ENOSYS"
in do_sys_futex() (or "#error" if no futex function is available).
Thanks,
Laurent
