From: Alistair Francis <alistair23@gmail.com>
To: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Cc: GNU C Library <libc-alpha@sourceware.org>
Subject: Re: [PATCH v2 04/14] linux: Add time64 pselect support
Date: Thu, 10 Sep 2020 12:35:58 -0700 [thread overview]
Message-ID: <CAKmqyKN0iPEpsto=unSiRw746FSkgoR2SBSeGz7NMA_=poXL4g@mail.gmail.com> (raw)
In-Reply-To: <20200908145738.640039-4-adhemerval.zanella@linaro.org>
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
>
next prev parent reply other threads:[~2020-09-10 19:47 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-08 14:57 [PATCH v2 01/14] linux: Simplify clock_getres Adhemerval Zanella
2020-09-08 14:57 ` [PATCH v2 02/14] linux: Add ppoll time64 optimization Adhemerval Zanella
2020-09-10 19:21 ` Alistair Francis
2020-09-08 14:57 ` [PATCH v2 03/14] linux: Add time64 semtimedop support Adhemerval Zanella
2020-09-10 19:23 ` Alistair Francis
2020-09-08 14:57 ` [PATCH v2 04/14] linux: Add time64 pselect support Adhemerval Zanella
2020-09-10 19:35 ` Alistair Francis [this message]
2020-09-12 1:22 ` H.J. Lu
2020-09-08 14:57 ` [PATCH v2 05/14] linux: Add time64 select support Adhemerval Zanella
2020-09-11 20:44 ` Alistair Francis
2020-09-08 14:57 ` [PATCH v2 06/14] linux: Add time64 sigtimedwait support Adhemerval Zanella
2020-09-11 20:56 ` Alistair Francis
2020-09-08 14:57 ` [PATCH v2 07/14] linux: Use 64-bit time_t syscall on clock_getcputclockid Adhemerval Zanella
2020-09-16 15:26 ` Alistair Francis
2020-09-08 14:57 ` [PATCH v2 08/14] linux: Consolidate utimes Adhemerval Zanella
2020-09-16 15:30 ` Alistair Francis
2020-09-08 14:57 ` [PATCH v2 09/14] linux: Fix time64 support for futimesat Adhemerval Zanella
2020-09-08 14:57 ` [PATCH v2 10/14] linux: Add time64 support for nanosleep Adhemerval Zanella
2020-09-16 17:16 ` Alistair Francis
2020-09-08 14:57 ` [PATCH v2 11/14] linux: Add time64 recvmmsg support Adhemerval Zanella
2020-09-25 21:18 ` Alistair Francis
2020-09-08 14:57 ` [RFC 12/14] linux: Add fallback for 64-bit time_t SO_{RCV,SND}TIMEO Adhemerval Zanella
2020-09-08 14:57 ` [RFC 13/14] linux: Add fallback for 64-bit time_t SO_TIMESTAMP{NS} Adhemerval Zanella
2020-09-08 14:57 ` [RFC 14/14] linux: Add recvvmsg " Adhemerval Zanella
2020-09-10 19:20 ` [PATCH v2 01/14] linux: Simplify clock_getres Alistair Francis
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