Re: [PATCH v2] linux-user/syscall: xtensa: fix ipc_perm conversion

[Richard Henderson <richard.henderson@linaro.org>]

On 3/29/24 12:33, Max Filippov wrote:
> target_ipc_perm::mode and target_ipc_perm::__seq fields are 32-bit wide
> on xtensa and thus need to use tswap32.
> The issue is spotted by the libc-test http://nsz.repo.hu/git/?p=libc-test
> on big-endian xtensa core.
> 
> Cc: qemu-stable@nongnu.org
> Fixes: a3da8be5126b ("target/xtensa: linux-user: fix sysv IPC structures")
> Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
> ---
> Changes v1->v2:
> - split into a separate patch
> 
>   linux-user/syscall.c | 10 ++++++----
>   1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index e384e1424890..d9bfd31c1cad 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -3758,12 +3758,13 @@ static inline abi_long target_to_host_ipc_perm(struct ipc_perm *host_ip,
>       host_ip->gid = tswap32(target_ip->gid);
>       host_ip->cuid = tswap32(target_ip->cuid);
>       host_ip->cgid = tswap32(target_ip->cgid);
> -#if defined(TARGET_ALPHA) || defined(TARGET_MIPS) || defined(TARGET_PPC)
> +#if defined(TARGET_ALPHA) || defined(TARGET_MIPS) || defined(TARGET_PPC) || \
> +    defined(TARGET_XTENSA)
>       host_ip->mode = tswap32(target_ip->mode);
>   #else
>       host_ip->mode = tswap16(target_ip->mode);
>   #endif

Oof.  I think we should rewrite these along the lines of __get_user_e, using 
__builtin_choose_expr and sizeof to choose the correct routine.


r~