[v2,04/14] linux: Add time64 pselect support

  Changes from previous version:

  * Move the 32-bit fallback implementation to pselect32.c.  It simplifies
    the required microblaze override.

---

The syscall __NR_pselect6_time64 (32-bit) or __NR_pselect6 (64-bit)
is used as default.  For architectures with __ASSUME_TIME64_SYSCALLS
the 32-bit fallback uses __NR_pselec6.

To accomodate microblaze missing pselect6 support on kernel older
than 3.15 the fallback is moved to its own function to the microblaze
specific implementation can override it.

Checked on x86_64-linux-gnu and i686-linux-gnu (on 5.4 and on 4.15
kernel).
---
 include/sys/select.h                          | 16 ++++++
 sysdeps/unix/sysv/linux/Makefile              |  2 +-
 .../microblaze/{pselect.c => pselect32.c}     | 34 ++++--------
 sysdeps/unix/sysv/linux/pselect.c             | 53 ++++++++++++++-----
 sysdeps/unix/sysv/linux/pselect32.c           | 47 ++++++++++++++++
 5 files changed, 116 insertions(+), 36 deletions(-)
 rename sysdeps/unix/sysv/linux/microblaze/{pselect.c => pselect32.c} (66%)
 create mode 100644 sysdeps/unix/sysv/linux/pselect32.c
  

On Tue, Sep 8, 2020 at 7:59 AM Adhemerval Zanella via Libc-alpha
<libc-alpha@sourceware.org> wrote:
>
> Changes from previous version:
>
>   * Move the 32-bit fallback implementation to pselect32.c.  It simplifies
>     the required microblaze override.

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

>
> ---
>
> The syscall __NR_pselect6_time64 (32-bit) or __NR_pselect6 (64-bit)
> is used as default.  For architectures with __ASSUME_TIME64_SYSCALLS
> the 32-bit fallback uses __NR_pselec6.
>
> To accomodate microblaze missing pselect6 support on kernel older
> than 3.15 the fallback is moved to its own function to the microblaze
> specific implementation can override it.
>
> Checked on x86_64-linux-gnu and i686-linux-gnu (on 5.4 and on 4.15
> kernel).
> ---
>  include/sys/select.h                          | 16 ++++++
>  sysdeps/unix/sysv/linux/Makefile              |  2 +-
>  .../microblaze/{pselect.c => pselect32.c}     | 34 ++++--------
>  sysdeps/unix/sysv/linux/pselect.c             | 53 ++++++++++++++-----
>  sysdeps/unix/sysv/linux/pselect32.c           | 47 ++++++++++++++++
>  5 files changed, 116 insertions(+), 36 deletions(-)
>  rename sysdeps/unix/sysv/linux/microblaze/{pselect.c => pselect32.c} (66%)
>  create mode 100644 sysdeps/unix/sysv/linux/pselect32.c
>
> diff --git a/include/sys/select.h b/include/sys/select.h
> index 07bb49b994..b5ae9af861 100644
> --- a/include/sys/select.h
> +++ b/include/sys/select.h
> @@ -3,6 +3,22 @@
>
>  #ifndef _ISOMAC
>  /* Now define the internal interfaces.  */
> +# if __TIMESIZE == 64
> +#  define __pselect64 __pselect
> +#else
> +# include <struct___timespec64.h>
> +extern int __pselect64 (int __nfds, fd_set *__readfds,
> +                       fd_set *__writefds, fd_set *__exceptfds,
> +                       const struct __timespec64 *__timeout,
> +                       const __sigset_t *__sigmask);
> +libc_hidden_proto (__pselect64)
> +
> +extern int __pselect32 (int __nfds, fd_set *__readfds,
> +                       fd_set *__writefds, fd_set *__exceptfds,
> +                       const struct __timespec64 *__timeout,
> +                       const __sigset_t *__sigmask)
> +  attribute_hidden;
> +#endif
>  extern int __pselect (int __nfds, fd_set *__readfds,
>                       fd_set *__writefds, fd_set *__exceptfds,
>                       const struct timespec *__timeout,
> diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
> index 5079f33655..03cb6e790d 100644
> --- a/sysdeps/unix/sysv/linux/Makefile
> +++ b/sysdeps/unix/sysv/linux/Makefile
> @@ -61,7 +61,7 @@ sysdep_routines += adjtimex clone umount umount2 readahead sysctl \
>                    open_by_handle_at mlock2 pkey_mprotect pkey_set pkey_get \
>                    timerfd_gettime timerfd_settime prctl \
>                    process_vm_readv process_vm_writev clock_adjtime \
> -                  time64-support
> +                  time64-support pselect32
>
>  CFLAGS-gethostid.c = -fexceptions
>  CFLAGS-tee.c = -fexceptions -fasynchronous-unwind-tables
> diff --git a/sysdeps/unix/sysv/linux/microblaze/pselect.c b/sysdeps/unix/sysv/linux/microblaze/pselect32.c
> similarity index 66%
> rename from sysdeps/unix/sysv/linux/microblaze/pselect.c
> rename to sysdeps/unix/sysv/linux/microblaze/pselect32.c
> index 1dfc3b8fc9..d7cfeaa0e9 100644
> --- a/sysdeps/unix/sysv/linux/microblaze/pselect.c
> +++ b/sysdeps/unix/sysv/linux/microblaze/pselect32.c
> @@ -23,38 +23,27 @@
>  #include <sysdep-cancel.h>
>
>  #ifndef __ASSUME_PSELECT
> -# define __pselect __pselect_syscall
> -#endif
> -
> -/* If pselect is supported, just use the Linux generic implementation.  */
> -#include <sysdeps/unix/sysv/linux/pselect.c>
> -
> -#ifndef __ASSUME_PSELECT
> -# undef __pselect
>  int
> -__pselect (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
> -          const struct timespec *timeout, const sigset_t *sigmask)
> +__pselect32 (int nfds, fd_set *readfds, fd_set *writefds,
> +            fd_set *exceptfds, const struct __timespec64 *timeout,
> +            const sigset_t *sigmask)
>  {
> -  int ret = __pselect_syscall (nfds, readfds, writefds, exceptfds, timeout,
> -                              sigmask);
> -  if (ret >= 0 || errno != ENOSYS)
> -    return ret;
> -
>    /* The fallback uses 'select' which shows the race condition regarding
>       signal mask set/restore, requires two additional syscalls, and has
>       a worse timeout precision (microseconds instead of nanoseconds).  */
>
> -  struct timeval tval, *ptval = NULL;
> +  struct timeval tv32, *ptv32 = NULL;
>    if (timeout != NULL)
>      {
> -      if (! valid_nanoseconds (timeout->tv_nsec))
> +      if (! in_time_t_range (timeout->tv_sec)
> +         || ! valid_nanoseconds (timeout->tv_nsec))
>         {
>           __set_errno (EINVAL);
>           return -1;
>         }
>
> -      TIMESPEC_TO_TIMEVAL (&tval, timeout);
> -      ptval = &tval;
> +      tv32 = valid_timespec64_to_timeval (*timeout);
> +      ptv32 = &tv32;
>      }
>
>    sigset_t savemask;
> @@ -62,12 +51,11 @@ __pselect (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
>      __sigprocmask (SIG_SETMASK, sigmask, &savemask);
>
>    /* select itself is a cancellation entrypoint.  */
> -  ret = __select (nfds, readfds, writefds, exceptfds, ptval);
> +  int r = __select (nfds, readfds, writefds, exceptfds, ptv32);
>
>    if (sigmask != NULL)
>      __sigprocmask (SIG_SETMASK, &savemask, NULL);
>
> -  return ret;
> +  return r;
>  }
> -weak_alias (__pselect, pselect)
> -#endif
> +#endif /* __ASSUME_PSELECT  */
> diff --git a/sysdeps/unix/sysv/linux/pselect.c b/sysdeps/unix/sysv/linux/pselect.c
> index 304db03338..ed36121023 100644
> --- a/sysdeps/unix/sysv/linux/pselect.c
> +++ b/sysdeps/unix/sysv/linux/pselect.c
> @@ -18,14 +18,15 @@
>
>  #include <sys/select.h>
>  #include <sysdep-cancel.h>
> +#include <time64-support.h>
>
>  int
> -__pselect (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
> -          const struct timespec *timeout, const sigset_t *sigmask)
> +__pselect64 (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
> +            const struct __timespec64 *timeout, const sigset_t *sigmask)
>  {
>    /* The Linux kernel can in some situations update the timeout value.
>       We do not want that so use a local variable.  */
> -  struct timespec tval;
> +  struct __timespec64 tval;
>    if (timeout != NULL)
>      {
>        tval = *timeout;
> @@ -36,18 +37,46 @@ __pselect (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
>       we can only pass in 6 directly.  If there is an architecture with
>       support for more parameters a new version of this file needs to
>       be created.  */
> -  struct
> -  {
> -    __syscall_ulong_t ss;
> -    __syscall_ulong_t ss_len;
> -  } data;
>
> -  data.ss = (__syscall_ulong_t) (uintptr_t) sigmask;
> -  data.ss_len = __NSIG_BYTES;
> +#ifndef __NR_pselect6_time64
> +# define __NR_pselect6_time64 __NR_pselect6
> +#endif
> +  int r;
> +  if (supports_time64 ())
> +    {
> +      r = SYSCALL_CANCEL (pselect6_time64, nfds, readfds, writefds, exceptfds,
> +                         timeout,
> +                         ((__syscall_ulong_t[]){ (uintptr_t) sigmask,
> +                                                 __NSIG_BYTES }));
> +      if (r == 0 || errno != ENOSYS)
> +       return r;
> +
> +      mark_time64_unsupported ();
> +    }
>
> -  return SYSCALL_CANCEL (pselect6, nfds, readfds, writefds, exceptfds,
> -                         timeout, &data);
> +#ifndef __ASSUME_TIME64_SYSCALLS
> +  r = __pselect32 (nfds, readfds, writefds, exceptfds, timeout, sigmask);
> +#endif
> +  return r;
>  }
> +
> +#if __TIMESIZE != 64
> +libc_hidden_def (__pselect64)
> +
> +int
> +__pselect (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
> +          const struct timespec *timeout, const sigset_t *sigmask)
> +{
> +  struct __timespec64 ts64, *pts64 = NULL;
> +  if (timeout != NULL)
> +    {
> +      ts64 = valid_timespec_to_timespec64 (*timeout);
> +      pts64 = &ts64;
> +    }
> +  return __pselect64 (nfds, readfds, writefds, exceptfds, pts64, sigmask);
> +}
> +#endif
> +
>  #ifndef __pselect
>  weak_alias (__pselect, pselect)
>  #endif
> diff --git a/sysdeps/unix/sysv/linux/pselect32.c b/sysdeps/unix/sysv/linux/pselect32.c
> new file mode 100644
> index 0000000000..0a2a7ac752
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/pselect32.c
> @@ -0,0 +1,47 @@
> +/* Synchronous I/O multiplexing.  Linux 32-bit time fallback.
> +   Copyright (C) 2020 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#include <sys/select.h>
> +#include <sysdep-cancel.h>
> +
> +#ifndef __ASSUME_TIME64_SYSCALLS
> +
> +int
> +__pselect32 (int nfds, fd_set *readfds, fd_set *writefds,
> +            fd_set *exceptfds, const struct __timespec64 *timeout,
> +            const sigset_t *sigmask)
> +{
> +  struct timespec ts32, *pts32 = NULL;
> +  if (timeout != NULL)
> +    {
> +      if (! in_time_t_range (timeout->tv_sec))
> +       {
> +         __set_errno (EINVAL);
> +         return -1;
> +       }
> +
> +      ts32 = valid_timespec64_to_timespec (*timeout);
> +      pts32 = &ts32;
> +    }
> +
> +  return SYSCALL_CANCEL (pselect6, nfds, readfds, writefds, exceptfds,
> +                        pts32,
> +                        ((__syscall_ulong_t[]){ (uintptr_t) sigmask,
> +                                                __NSIG_BYTES }));
> +}
> +#endif
> --
> 2.25.1
>
  

On Tue, Sep 8, 2020 at 7:59 AM Adhemerval Zanella via Libc-alpha
<libc-alpha@sourceware.org> wrote:
>
> Changes from previous version:
>
>   * Move the 32-bit fallback implementation to pselect32.c.  It simplifies
>     the required microblaze override.
>
> ---
>
> The syscall __NR_pselect6_time64 (32-bit) or __NR_pselect6 (64-bit)
> is used as default.  For architectures with __ASSUME_TIME64_SYSCALLS
> the 32-bit fallback uses __NR_pselec6.
>
> To accomodate microblaze missing pselect6 support on kernel older
> than 3.15 the fallback is moved to its own function to the microblaze
> specific implementation can override it.
>
> Checked on x86_64-linux-gnu and i686-linux-gnu (on 5.4 and on 4.15
> kernel).

This breaks x32:

FAIL: misc/tst-pselect
FAIL: nptl/tst-cancelx4
FAIL: nptl/tst-cancelx5