Re: [PATCH 17/21] linux-user/s390x: Implement setup_sigtramp

[Philippe Mathieu-Daudé]

On 6/16/21 3:12 AM, Richard Henderson wrote:
> Create and record the two signal trampolines.
> Use them when the guest does not use SA_RESTORER.
> 
> Cc: qemu-s390x@nongnu.org
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  linux-user/s390x/target_signal.h |  2 ++
>  linux-user/s390x/signal.c        | 24 ++++++++++++++++--------
>  2 files changed, 18 insertions(+), 8 deletions(-)

> +void setup_sigtramp(abi_ulong sigtramp_page)
> +{
> +    uint16_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 4, 0);

4 -> 2 + 2 seems clearer (applies to some other targets in this series).

> +    assert(tramp != NULL);
> +
> +    default_sigreturn = sigtramp_page;
> +    __put_user(S390_SYSCALL_OPCODE | TARGET_NR_sigreturn, &tramp[0]);
> +
> +    default_rt_sigreturn = sigtramp_page + 2;
> +    __put_user(S390_SYSCALL_OPCODE | TARGET_NR_rt_sigreturn, &tramp[1]);
> +
> +    unlock_user(tramp, sigtramp_page, 4);

Ditto, otherwise:
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

> +}
>