Update copyright dates with scripts/update-copyrights

[thirdparty/glibc.git] / sysdeps / unix / sysv / linux / kernel-features.h

diff --git a/sysdeps/unix/sysv/linux/kernel-features.h b/sysdeps/unix/sysv/linux/kernel-features.h
index 1518bb522878bc251dc99121a23ba55e8a714443..1680b10ca1b6e9df096498fa196af4694def5d6e 100644 (file)
--- a/sysdeps/unix/sysv/linux/kernel-features.h
+++ b/sysdeps/unix/sysv/linux/kernel-features.h
@@ -1,6 +1,6 @@
 /* Set flags signalling availability of kernel features based on given
    kernel version number.
-   Copyright (C) 1999-2019 Free Software Foundation, Inc.
+   Copyright (C) 1999-2021 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
@@ -15,11 +15,16 @@
 
    You should have received a copy of the GNU Lesser General Public
    License along with the GNU C Library; if not, see
-   <http://www.gnu.org/licenses/>.  */
+   <https://www.gnu.org/licenses/>.  */
 
 /* This file must not contain any C code.  At least it must be protected
    to allow using the file also in assembler files.  */
 
+#ifndef _LINUX_KERNEL_FEATURES_H
+#define _LINUX_KERNEL_FEATURES_H 1
+
+#include <bits/wordsize.h>
+
 #ifndef __LINUX_KERNEL_VERSION
 /* We assume the worst; all kernels should be supported.  */
 # define __LINUX_KERNEL_VERSION        0
@@ -44,10 +49,6 @@
    SH this appeared first in 2.6.19-rc1, on ia64 in 2.6.22-rc1.  */
 #define __ASSUME_PSELECT       1
 
-/* The *at syscalls were introduced just after 2.6.16-rc1.  On PPC
-   they were introduced in 2.6.17-rc1, on SH in 2.6.19-rc1.  */
-#define __ASSUME_ATFCTS        1
-
 /* Support for inter-process robust mutexes was added in 2.6.17 (but
    some architectures lack futex_atomic_cmpxchg_inatomic in some
    configurations).  */
@@ -80,6 +81,17 @@
 /* Support for SysV IPC through wired syscalls.  All supported architectures
    either support ipc syscall and/or all the ipc correspondent syscalls.  */
 #define __ASSUME_DIRECT_SYSVIPC_SYSCALLS       1
+/* The generic default __IPC_64 value is 0x0, however some architectures
+   require a different value of 0x100.  */
+#define __ASSUME_SYSVIPC_DEFAULT_IPC_64                1
+
+/* All supported architectures reserve a 32-bit for MODE field in sysvipc
+   ipc_perm.  However, some kernel ABI interfaces still expect a 16-bit
+   field.  This is only an issue if arch-defined IPC_PERM padding is on a
+   wrong position regarding endianness.  In this case, the IPC control
+   routines (msgctl, semctl, and semtctl) requires to shift the value to
+   correct place.
+   The ABIs that requires it define __ASSUME_SYSVIPC_BROKEN_MODE_T.  */
 
 /* Support for p{read,write}v2 was added in 4.6.  However Linux default
    implementation does not assume the __ASSUME_* and instead use a fallback
@@ -139,3 +151,71 @@
    */
 
 #define __ASSUME_CLONE_DEFAULT 1
+
+/* Support for 64-bit time_t in the system call interface.  When this
+   flag is set, the kernel provides a version of each of these system
+   calls that accepts 64-bit time_t:
+
+     clock_adjtime(64)
+     clock_gettime(64)
+     clock_settime(64)
+     clock_getres(_time64)
+     clock_nanosleep(_time64)
+     futex(_time64)
+     mq_timedreceive(_time64)
+     mq_timedsend(_time64)
+     ppoll(_time64)
+     pselect6(_time64)
+     rt_sigtimedwait(_time64)
+     sched_rr_get_interval(_time64)
+     timer_gettime(64)
+     timer_settime(64)
+     timerfd_gettime(64)
+     timerfd_settime(64)
+     utimensat(_time64)
+
+   On architectures where time_t has historically been 64 bits,
+   only the 64-bit version of each system call exists, and there
+   are no suffixes on the __NR_ constants.
+
+   On architectures where time_t has historically been 32 bits,
+   both 32-bit and 64-bit versions of each system call may exist,
+   depending on the kernel version.  When the 64-bit version exists,
+   there is a '64' or '_time64' suffix on the name of its __NR_
+   constant, as shown above.
+
+   This flag is always set for Linux 5.1 and later.  Prior to that
+   version, it is set only for some CPU architectures and ABIs:
+
+   - __WORDSIZE == 64 - all supported architectures where pointers
+     are 64 bits also have always had 64-bit time_t.
+
+   - __WORDSIZE == 32 && __SYSCALL_WORDSIZE == 64 - this describes
+     only one supported configuration, x86's 'x32' subarchitecture,
+     where pointers are 32 bits but time_t has always been 64 bits.
+
+   __ASSUME_TIME64_SYSCALLS being set does not mean __TIMESIZE is 64,
+   and __TIMESIZE equal to 64 does not mean __ASSUME_TIME64_SYSCALLS
+   is set.  All four cases are possible.  */
+
+#if __LINUX_KERNEL_VERSION >= 0x050100                          \
+  || __WORDSIZE == 64                                           \
+  || (defined __SYSCALL_WORDSIZE && __SYSCALL_WORDSIZE == 64)
+# define __ASSUME_TIME64_SYSCALLS 1
+#endif
+
+/* Linux waitid prior kernel 5.4 does not support waiting for the current
+   process group.  */
+#if __LINUX_KERNEL_VERSION >= 0x050400
+# define __ASSUME_WAITID_PID0_P_PGID
+#endif
+
+/* The faccessat2 system call was introduced across all architectures
+   in Linux 5.8.  */
+#if __LINUX_KERNEL_VERSION >= 0x050800
+# define __ASSUME_FACCESSAT2 1
+#else
+# define __ASSUME_FACCESSAT2 0
+#endif
+
+#endif /* kernel-features.h */