Re: [PATCH v2] linux-user: support of semtimedop syscall

[Laurent Vivier <laurent@vivier.eu>]

Le 28/05/2020 à 19:10, Laurent Vivier a écrit :
> Le 12/05/2020 à 09:45, Matus Kysel a écrit :
>> We should add support of semtimedop syscall as new version of
>> glibc 2.31 uses semop based on semtimedop (commit: https://gitlab.com/freedesktop-sdk/mirrors/sourceware/glibc/-/commit/765cdd0bffd77960ae852104fc4ea5edcdb8aed3 ).
>>
>> Signed-off-by: Matus Kysel <mkysel@tachyum.com>
>> ---
>>  linux-user/syscall.c | 34 ++++++++++++++++++++++++++++------
>>  1 file changed, 28 insertions(+), 6 deletions(-)
>>
>> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
>> index 05f03919ff..7c6f9439e0 100644
>> --- a/linux-user/syscall.c
>> +++ b/linux-user/syscall.c
>> @@ -1227,7 +1227,8 @@ static inline abi_long copy_to_user_timeval64(abi_ulong target_tv_addr,
>>      defined(TARGET_NR_pselect6) || defined(TARGET_NR_pselect6) || \
>>      defined(TARGET_NR_nanosleep) || defined(TARGET_NR_clock_settime) || \
>>      defined(TARGET_NR_utimensat) || defined(TARGET_NR_mq_timedsend) || \
>> -    defined(TARGET_NR_mq_timedreceive)
>> +    defined(TARGET_NR_mq_timedreceive) || defined(TARGET_NR_ipc) || \
>> +    defined(TARGET_NR_semop) || defined(TARGET_NR_semtimedop)
>>  static inline abi_long target_to_host_timespec(struct timespec *host_ts,
>>                                                 abi_ulong target_addr)
>>  {
>> @@ -3875,25 +3876,39 @@ static inline abi_long target_to_host_sembuf(struct sembuf *host_sembuf,
>>      return 0;
>>  }
>>
>> -static inline abi_long do_semop(int semid, abi_long ptr, unsigned nsops)
>> +#if defined(TARGET_NR_ipc) || defined(TARGET_NR_semop) || \
>> +    defined(TARGET_NR_semtimedop)
>> +static inline abi_long do_semtimedop(int semid,
>> +                                     abi_long ptr,
>> +                                     unsigned nsops,
>> +                                     abi_long timeout)
>>  {
>>      struct sembuf sops[nsops];
>> +    struct timespec ts, *pts = NULL;
>>      abi_long ret;
>>
>> +    if (timeout) {
>> +        pts = &ts;
>> +        if (target_to_host_timespec(pts, timeout)) {
>> +            return -TARGET_EFAULT;
>> +        }
>> +    }
>> +
>>      if (target_to_host_sembuf(sops, ptr, nsops))
>>          return -TARGET_EFAULT;
>>
>>      ret = -TARGET_ENOSYS;
>>  #ifdef __NR_semtimedop
>> -    ret = get_errno(safe_semtimedop(semid, sops, nsops, NULL));
>> +    ret = get_errno(safe_semtimedop(semid, sops, nsops, pts));
>>  #endif
>>  #ifdef __NR_ipc
>>      if (ret == -TARGET_ENOSYS) {
>> -        ret = get_errno(safe_ipc(IPCOP_semtimedop, semid, nsops, 0, sops, 0));
>> +        ret = get_errno(safe_ipc(IPCOP_semtimedop, semid, nsops, 0, sops, pts));
>>      }
>>  #endif
>>      return ret;
>>  }
>> +#endif
>>
>>  struct target_msqid_ds
>>  {
>> @@ -4369,7 +4384,10 @@ static abi_long do_ipc(CPUArchState *cpu_env,
>>
>>      switch (call) {
>>      case IPCOP_semop:
>> -        ret = do_semop(first, ptr, second);
>> +        ret = do_semtimedop(first, ptr, second, 0);
>> +        break;
>> +    case IPCOP_semtimedop:
>> +        ret = do_semtimedop(first, ptr, second, third);
>>          break;
>>
>>      case IPCOP_semget:
>> @@ -9594,7 +9612,11 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
>>  #endif
>>  #ifdef TARGET_NR_semop
>>      case TARGET_NR_semop:
>> -        return do_semop(arg1, arg2, arg3);
>> +        return do_semtimedop(arg1, arg2, arg3, 0);
>> +#endif
>> +#ifdef TARGET_NR_semtimedop
>> +    case TARGET_NR_semtimedop:
>> +        return do_semtimedop(arg1, arg2, arg3, arg4);
>>  #endif
>>  #ifdef TARGET_NR_semctl
>>      case TARGET_NR_semctl:
>> --
>> 2.17.1
>>
>>
> 
> Applied to my linux-user branch.

I'm sorry I have to remove this patch from my queue as it fails to build
on ppc64 and s390x:

ppc64: https://travis-ci.com/github/vivier/qemu/jobs/342816606
s390x: https://travis-ci.com/github/vivier/qemu/jobs/342816607

For ppc64 (and other targets in fact), I think we just need a (long)
cast on pts.

For s390x, it is clearly because ipc() has arguments in a different
order. In glibc we have:

sysdeps/unix/sysv/linux/semtimedop.c:

  return INLINE_SYSCALL_CALL (ipc, IPCOP_semtimedop, semid,
                              SEMTIMEDOP_IPC_ARGS (nsops, sops, timeout));

sysdeps/unix/sysv/linux/ipc_priv.h:

/* This macro is required to handle the s390 variants, which passes the
   arguments in a different order than default.  */
#define SEMTIMEDOP_IPC_ARGS(__nsops, __sops, __timeout) \
  (__nsops), 0, (__sops), (__timeout)

sysdeps/unix/sysv/linux/s390/ipc_priv.h:

/* The s390 sys_ipc variant has only five parameters instead of six
   (as for default variant).  The difference is the handling of
   SEMTIMEDOP where on s390 the third parameter is used as a pointer
   to a struct timespec where the generic variant uses fifth parameter.  */
#undef SEMTIMEDOP_IPC_ARGS
#define SEMTIMEDOP_IPC_ARGS(__nsops, __sops, __timeout) \
  (__nsops), (__timeout), (__sops)

To be really clean the do_ipc() function should be also updated for the
s390x target side.

Thanks,
Laurent