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glibc/sysdeps/unix/sysv/linux/microblaze/pselect32.c

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misc: Set generic pselect as ENOSYS The generic pselect implementation has the very specific race condition that motived the creation of the pselect syscall (no atomicity in signal mask set/reset). Using it as generic implementation is counterproductive Also currently only microblaze uses it as fallback when used on kernel prior 3.15. This patch moves the generic implementation to a microblaze specific one, sets the generic internal as a ENOSYS, and cleanups the Linux generic implementation. The microblaze implementation mimics the previous Linux generic one, where it either uses pselect6 directly if __ASSUME_PSELECT or a first try pselect6 then the fallback otherwise. Checked on x86_64-linux-gnu and microblaze-linux-gnu.
2019-11-14 21:18:24 +00:00
/* Synchronous I/O multiplexing. Linux/microblaze version.
Update copyright dates with scripts/update-copyrights
2023-01-06 21:08:04 +00:00
Copyright (C) 2019-2023 Free Software Foundation, Inc.
misc: Set generic pselect as ENOSYS The generic pselect implementation has the very specific race condition that motived the creation of the pselect syscall (no atomicity in signal mask set/reset). Using it as generic implementation is counterproductive Also currently only microblaze uses it as fallback when used on kernel prior 3.15. This patch moves the generic implementation to a microblaze specific one, sets the generic internal as a ENOSYS, and cleanups the Linux generic implementation. The microblaze implementation mimics the previous Linux generic one, where it either uses pselect6 directly if __ASSUME_PSELECT or a first try pselect6 then the fallback otherwise. Checked on x86_64-linux-gnu and microblaze-linux-gnu.
2019-11-14 21:18:24 +00:00
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 <errno.h>
#include <signal.h>
#include <time.h>
#include <sys/poll.h>
#include <sysdep-cancel.h>
microblaze: Add missing implementation when !__ASSUME_TIME64_SYSCALLS In commit a92f4e6299fe0e3cb6f77e79de00817aece501ce ("linux: Add time64 pselect support"), a Microblaze specific implementation of __pselect32() was added to cover the case of kernels < 3.15 which lack the pselect6 system call. This new file sysdeps/unix/sysv/linux/microblaze/pselect32.c takes precedence over the default implementation sysdeps/unix/sysv/linux/pselect32.c. However sysdeps/unix/sysv/linux/pselect32.c provides an implementation of __pselect32() which is needed when __ASSUME_TIME64_SYSCALLS is not defined. On Microblaze, which is a 32-bit architecture, __ASSUME_TIME64_SYSCALLS is only true for kernels >= 5.1. Due to sysdeps/unix/sysv/linux/microblaze/pselect32.c taking precedence over sysdeps/unix/sysv/linux/pselect32.c, it means that when we are with a kernel >= 3.15 but < 5.1, we need a __pselect32() implementation, but sysdeps/unix/sysv/linux/microblaze/pselect32.c doesn't provide it, and sysdeps/unix/sysv/linux/pselect32.c which would provide it is not compiled in. This causes the following build failure on Microblaze with for example Linux kernel headers 4.9: [...]/build/libc_pic.os: in function `__pselect64': (.text+0x120b44): undefined reference to `__pselect32' collect2: error: ld returned 1 exit status Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2021-12-28 12:09:49 +00:00
#ifndef __ASSUME_TIME64_SYSCALL
#include <sysdeps/unix/sysv/linux/pselect32.c>
#elif !defined __ASSUME_PSELECT
misc: Set generic pselect as ENOSYS The generic pselect implementation has the very specific race condition that motived the creation of the pselect syscall (no atomicity in signal mask set/reset). Using it as generic implementation is counterproductive Also currently only microblaze uses it as fallback when used on kernel prior 3.15. This patch moves the generic implementation to a microblaze specific one, sets the generic internal as a ENOSYS, and cleanups the Linux generic implementation. The microblaze implementation mimics the previous Linux generic one, where it either uses pselect6 directly if __ASSUME_PSELECT or a first try pselect6 then the fallback otherwise. Checked on x86_64-linux-gnu and microblaze-linux-gnu.
2019-11-14 21:18:24 +00:00
int
linux: Add time64 pselect support 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). Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
2020-07-06 16:27:12 +00:00
__pselect32 (int nfds, fd_set *readfds, fd_set *writefds,
fd_set *exceptfds, const struct __timespec64 *timeout,
const sigset_t *sigmask)
misc: Set generic pselect as ENOSYS The generic pselect implementation has the very specific race condition that motived the creation of the pselect syscall (no atomicity in signal mask set/reset). Using it as generic implementation is counterproductive Also currently only microblaze uses it as fallback when used on kernel prior 3.15. This patch moves the generic implementation to a microblaze specific one, sets the generic internal as a ENOSYS, and cleanups the Linux generic implementation. The microblaze implementation mimics the previous Linux generic one, where it either uses pselect6 directly if __ASSUME_PSELECT or a first try pselect6 then the fallback otherwise. Checked on x86_64-linux-gnu and microblaze-linux-gnu.
2019-11-14 21:18:24 +00:00
{
/* 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). */
linux: Add time64 pselect support 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). Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
2020-07-06 16:27:12 +00:00
struct timeval tv32, *ptv32 = NULL;
misc: Set generic pselect as ENOSYS The generic pselect implementation has the very specific race condition that motived the creation of the pselect syscall (no atomicity in signal mask set/reset). Using it as generic implementation is counterproductive Also currently only microblaze uses it as fallback when used on kernel prior 3.15. This patch moves the generic implementation to a microblaze specific one, sets the generic internal as a ENOSYS, and cleanups the Linux generic implementation. The microblaze implementation mimics the previous Linux generic one, where it either uses pselect6 directly if __ASSUME_PSELECT or a first try pselect6 then the fallback otherwise. Checked on x86_64-linux-gnu and microblaze-linux-gnu.
2019-11-14 21:18:24 +00:00
if (timeout != NULL)
{
linux: Only use 64-bit syscall if required for pselect For !__ASSUME_TIME64_SYSCALLS there is no need to issue a 64-bit syscall if the provided timeout fits in a 32-bit one. The 64-bit usage should be rare since the timeout is a relative one. This also avoids the need to use supports_time64() (which breaks the usage case of live migration like CRIU or similar). Checked on i686-linux-gnu on a 4.15 kernel and on a 5.11 kernel (with and without --enable-kernel=5.1) and on x86_64-linux-gnu. Reviewed-by: Lukasz Majewski <lukma@denx.de>
2021-06-15 19:59:50 +00:00
if (! valid_nanoseconds (timeout->tv_nsec))
misc: Set generic pselect as ENOSYS The generic pselect implementation has the very specific race condition that motived the creation of the pselect syscall (no atomicity in signal mask set/reset). Using it as generic implementation is counterproductive Also currently only microblaze uses it as fallback when used on kernel prior 3.15. This patch moves the generic implementation to a microblaze specific one, sets the generic internal as a ENOSYS, and cleanups the Linux generic implementation. The microblaze implementation mimics the previous Linux generic one, where it either uses pselect6 directly if __ASSUME_PSELECT or a first try pselect6 then the fallback otherwise. Checked on x86_64-linux-gnu and microblaze-linux-gnu.
2019-11-14 21:18:24 +00:00
{
__set_errno (EINVAL);
return -1;
}
linux: Add time64 pselect support 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). Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
2020-07-06 16:27:12 +00:00
tv32 = valid_timespec64_to_timeval (*timeout);
ptv32 = &tv32;
misc: Set generic pselect as ENOSYS The generic pselect implementation has the very specific race condition that motived the creation of the pselect syscall (no atomicity in signal mask set/reset). Using it as generic implementation is counterproductive Also currently only microblaze uses it as fallback when used on kernel prior 3.15. This patch moves the generic implementation to a microblaze specific one, sets the generic internal as a ENOSYS, and cleanups the Linux generic implementation. The microblaze implementation mimics the previous Linux generic one, where it either uses pselect6 directly if __ASSUME_PSELECT or a first try pselect6 then the fallback otherwise. Checked on x86_64-linux-gnu and microblaze-linux-gnu.
2019-11-14 21:18:24 +00:00
}
sigset_t savemask;
if (sigmask != NULL)
__sigprocmask (SIG_SETMASK, sigmask, &savemask);
/* select itself is a cancellation entrypoint. */
linux: Add time64 pselect support 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). Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
2020-07-06 16:27:12 +00:00
int ret = __select (nfds, readfds, writefds, exceptfds, ptv32);
misc: Set generic pselect as ENOSYS The generic pselect implementation has the very specific race condition that motived the creation of the pselect syscall (no atomicity in signal mask set/reset). Using it as generic implementation is counterproductive Also currently only microblaze uses it as fallback when used on kernel prior 3.15. This patch moves the generic implementation to a microblaze specific one, sets the generic internal as a ENOSYS, and cleanups the Linux generic implementation. The microblaze implementation mimics the previous Linux generic one, where it either uses pselect6 directly if __ASSUME_PSELECT or a first try pselect6 then the fallback otherwise. Checked on x86_64-linux-gnu and microblaze-linux-gnu.
2019-11-14 21:18:24 +00:00
if (sigmask != NULL)
__sigprocmask (SIG_SETMASK, &savemask, NULL);
return ret;
}
linux: Add time64 pselect support 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). Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
2020-07-06 16:27:12 +00:00
#endif /* __ASSUME_PSELECT */
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