/* Set flags signalling availability of kernel features based on given
kernel version number.
- Copyright (C) 1999-2014 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
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
introduced. If somebody cares these values can afterwards be
corrected. */
-/* The sendfile syscall was introduced in 2.2.0. */
-#define __ASSUME_SENDFILE 1
-
-/* Linux 2.3.39 introduced IPC64. Except for powerpc. Linux 2.4.0 on
- PPC introduced a correct IPC64. But PowerPC64 does not support a
- separate 64-bit syscall, already 64-bit. */
-#ifndef __powerpc64__
-# define __ASSUME_IPC64 1
-#endif
-
-/* The changed st_ino field appeared in 2.4.0-test6. However, SH is lame,
- and still does not have a 64-bit inode field. */
-#ifndef __sh__
-# define __ASSUME_ST_INO_64_BIT 1
-#endif
-
-/* The getdents64 syscall was introduced in 2.4.0-test7 (but later for
- MIPS n32). */
-#define __ASSUME_GETDENTS64_SYSCALL 1
-
/* The statfs64 syscalls are available in 2.5.74 (but not for alpha). */
#define __ASSUME_STATFS64 1
-/* The utimes syscall has been available for some architectures
- forever. For x86 it was introduced after 2.5.75, for x86-64,
- ppc, and ppc64 it was introduced in 2.6.0-test3, for s390 it was
- introduced in 2.6.21-rc5. */
-#if defined __sparc__ \
- || defined __i386__ \
- || defined __x86_64__ \
- || defined __powerpc__ \
- || defined __sh__ \
- || (defined __s390__ && __LINUX_KERNEL_VERSION >= 0x020616)
-# define __ASSUME_UTIMES 1
-#endif
-
-/* pselect/ppoll were introduced just after 2.6.16-rc1. Due to the way
- the kernel versions are advertised we can only rely on 2.6.17 to have
- the code. On x86_64 and SH this appeared first in 2.6.19-rc1,
- on ia64 in 2.6.22-rc1. */
-#if __LINUX_KERNEL_VERSION >= 0x020611 \
- && ((!defined __x86_64__ && !defined __sh__) \
- || (__LINUX_KERNEL_VERSION >= 0x020613 \
- && (defined __x86_64__ || defined __sh__)))
-# define __ASSUME_PSELECT 1
-# define __ASSUME_PPOLL 1
-#endif
-
-/* The *at syscalls were introduced just after 2.6.16-rc1. Due to the way the
- kernel versions are advertised we can only rely on 2.6.17 to have
- the code. On PPC they were introduced in 2.6.17-rc1,
- on SH in 2.6.19-rc1. */
-#if __LINUX_KERNEL_VERSION >= 0x020611 \
- && (!defined __sh__ || __LINUX_KERNEL_VERSION >= 0x020613)
-# define __ASSUME_ATFCTS 1
-#endif
-
-/* Support for inter-process robust mutexes was added in 2.6.17. */
-#if __LINUX_KERNEL_VERSION >= 0x020611 \
- && (!defined __sh__ || __LINUX_KERNEL_VERSION >= 0x020613)
-# define __ASSUME_SET_ROBUST_LIST 1
-#endif
-
-/* Pessimistically assume that 2.6.18 introduced real handling of
- large numbers of requests to readv and writev and that we don't
- need a fallback. It likely worked for much longer. */
-#if __LINUX_KERNEL_VERSION >= 0x020612
-# define __ASSUME_COMPLETE_READV_WRITEV 1
-#endif
-
-/* Support for PI futexes was added in 2.6.18. */
-#if __LINUX_KERNEL_VERSION >= 0x020612
-# define __ASSUME_FUTEX_LOCK_PI 1
-#endif
-
-/* Support for utimensat syscall was added in 2.6.22, on SH
- only after 2.6.22-rc1. */
-#if __LINUX_KERNEL_VERSION >= 0x020616 \
- && (!defined __sh__ || __LINUX_KERNEL_VERSION >= 0x020617)
-# define __ASSUME_UTIMENSAT 1
-#endif
-
-/* Support for private futexes was added in 2.6.22. */
-#if __LINUX_KERNEL_VERSION >= 0x020616
-# define __ASSUME_PRIVATE_FUTEX 1
-#endif
-
-/* Support for fallocate was added in 2.6.23, on s390
- only after 2.6.23-rc1. */
-#if __LINUX_KERNEL_VERSION >= 0x020617 \
- && (!defined __s390__ || __LINUX_KERNEL_VERSION >= 0x020618)
-# define __ASSUME_FALLOCATE 1
-#endif
-
-/* Support for various CLOEXEC and NONBLOCK flags was added for x86,
- x86-64, PPC, IA-64, SPARC< and S390 in 2.6.23. */
-#if __LINUX_KERNEL_VERSION >= 0x020617 \
- && (defined __i386__ || defined __x86_64__ || defined __powerpc__ \
- || defined __sparc__ || defined __s390__)
-# define __ASSUME_O_CLOEXEC 1
-#endif
-
-/* From 2.6.23 onwards the value of ARG_MAX depends on the stack
- size. */
-#define __LINUX_ARG_MAX_STACK_BASED_MIN_KERNEL 0x020617
-#if __LINUX_KERNEL_VERSION >= __LINUX_ARG_MAX_STACK_BASED_MIN_KERNEL
-# define __ASSUME_ARG_MAX_STACK_BASED 1
-#endif
-
-/* Support for ADJ_OFFSET_SS_READ was added in 2.6.24. */
-#if __LINUX_KERNEL_VERSION >= 0x020618
-# define __ASSUME_ADJ_OFFSET_SS_READ 1
-#endif
-
-/* Support for various CLOEXEC and NONBLOCK flags was added for x86,
- x86-64, PPC, IA-64, and SPARC in 2.6.27. */
-#if __LINUX_KERNEL_VERSION >= 0x02061b \
- && (defined __i386__ || defined __x86_64__ || defined __powerpc__ \
- || defined __sparc__ || defined __s390__)
-# define __ASSUME_SOCK_CLOEXEC 1
-# define __ASSUME_IN_NONBLOCK 1
-# define __ASSUME_PIPE2 1
-# define __ASSUME_EVENTFD2 1
-# define __ASSUME_SIGNALFD4 1
-# define __ASSUME_DUP3 1
-#endif
+/* pselect/ppoll were introduced just after 2.6.16-rc1. On x86_64 and
+ SH this appeared first in 2.6.19-rc1, on ia64 in 2.6.22-rc1. */
+#define __ASSUME_PSELECT 1
-/* Support for the accept4 syscall was added in 2.6.28. */
-#if __LINUX_KERNEL_VERSION >= 0x02061c \
- && (defined __i386__ || defined __x86_64__ || defined __powerpc__ \
- || defined __sparc__ || defined __s390__)
-# define __ASSUME_ACCEPT4 1
-#endif
-
-/* Support for the FUTEX_CLOCK_REALTIME flag was added in 2.6.29. */
-#if __LINUX_KERNEL_VERSION >= 0x02061d
-# define __ASSUME_FUTEX_CLOCK_REALTIME 1
-#endif
+/* Support for inter-process robust mutexes was added in 2.6.17 (but
+ some architectures lack futex_atomic_cmpxchg_inatomic in some
+ configurations). */
+#define __ASSUME_SET_ROBUST_LIST 1
-/* Support for the AT_RANDOM auxiliary vector entry was added in 2.6.29. */
-#if __LINUX_KERNEL_VERSION >= 0x02061d
-# define __ASSUME_AT_RANDOM 1
-#endif
+/* Support for various CLOEXEC and NONBLOCK flags was added in
+ 2.6.27. */
+#define __ASSUME_IN_NONBLOCK 1
/* Support for preadv and pwritev was added in 2.6.30. */
-#if __LINUX_KERNEL_VERSION >= 0x02061e
-# define __ASSUME_PREADV 1
-# define __ASSUME_PWRITEV 1
-#endif
+#define __ASSUME_PREADV 1
+#define __ASSUME_PWRITEV 1
+
+/* Support for sendmmsg functionality was added in 3.0. */
+#define __ASSUME_SENDMMSG 1
+
+/* On most architectures, most socket syscalls are supported for all
+ supported kernel versions, but on some socketcall architectures
+ separate syscalls were only added later. */
+#define __ASSUME_SENDMSG_SYSCALL 1
+#define __ASSUME_RECVMSG_SYSCALL 1
+#define __ASSUME_ACCEPT_SYSCALL 1
+#define __ASSUME_CONNECT_SYSCALL 1
+#define __ASSUME_RECVFROM_SYSCALL 1
+#define __ASSUME_SENDTO_SYSCALL 1
+#define __ASSUME_ACCEPT4_SYSCALL 1
+#define __ASSUME_RECVMMSG_SYSCALL 1
+#define __ASSUME_SENDMMSG_SYSCALL 1
+
+/* 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
+ implementation based on p{read,write}v and returning an error for
+ non supported flags. */
+
+/* Support for the renameat2 system call was added in kernel 3.15. */
+#if __LINUX_KERNEL_VERSION >= 0x030F00
+# define __ASSUME_RENAMEAT2
+#endif
+
+/* Support for the execveat syscall was added in 3.19. */
+#if __LINUX_KERNEL_VERSION >= 0x031300
+# define __ASSUME_EXECVEAT 1
+#endif
+
+#if __LINUX_KERNEL_VERSION >= 0x040400
+# define __ASSUME_MLOCK2 1
+#endif
+
+/* Support for statx was added in kernel 4.11. */
+#if __LINUX_KERNEL_VERSION >= 0x040B00
+# define __ASSUME_STATX 1
+#endif
+
+/* Support for clone call used on fork. The signature varies across the
+ architectures with current 4 different variants:
+
+ 1. long int clone (unsigned long flags, unsigned long newsp,
+ int *parent_tidptr, unsigned long tls,
+ int *child_tidptr)
+
+ 2. long int clone (unsigned long newsp, unsigned long clone_flags,
+ int *parent_tidptr, int * child_tidptr,
+ unsigned long tls)
+
+ 3. long int clone (unsigned long flags, unsigned long newsp,
+ int stack_size, int *parent_tidptr,
+ int *child_tidptr, unsigned long tls)
+
+ 4. long int clone (unsigned long flags, unsigned long newsp,
+ int *parent_tidptr, int *child_tidptr,
+ unsigned long tls)
+
+ The fourth variant is intended to be used as the default for newer ports,
+ Also IA64 uses the third variant but with __NR_clone2 instead of
+ __NR_clone.
+
+ The macros names to define the variant used for the architecture is
+ similar to kernel:
+
+ - __ASSUME_CLONE_BACKWARDS: for variant 1.
+ - __ASSUME_CLONE_BACKWARDS2: for variant 2 (s390).
+ - __ASSUME_CLONE_BACKWARDS3: for variant 3 (microblaze).
+ - __ASSUME_CLONE_DEFAULT: for variant 4.
+ - __ASSUME_CLONE2: for clone2 with variant 3 (ia64).
+ */
+
+#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.
-/* Support for FUTEX_*_REQUEUE_PI was added in 2.6.31. */
-#if __LINUX_KERNEL_VERSION >= 0x02061f
-# define __ASSUME_REQUEUE_PI 1
-#endif
+ 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.
-/* Support for F_GETOWN_EX was introduced in 2.6.32. */
-#if __LINUX_KERNEL_VERSION >= 0x020620
-# define __ASSUME_F_GETOWN_EX 1
-#endif
+ 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:
-/* Support for the recvmmsg syscall was added in 2.6.33. */
-#if __LINUX_KERNEL_VERSION >= 0x020621
-# define __ASSUME_RECVMMSG 1
-#endif
+ - __WORDSIZE == 64 - all supported architectures where pointers
+ are 64 bits also have always had 64-bit time_t.
-/* statfs fills in f_flags since 2.6.36. */
-#if __LINUX_KERNEL_VERSION >= 0x020624
-# define __ASSUME_STATFS_F_FLAGS 1
-#endif
+ - __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.
-/* prlimit64 is available in 2.6.36. */
-#if __LINUX_KERNEL_VERSION >= 0x020624
-# define __ASSUME_PRLIMIT64 1
-#endif
+ __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. */
-/* sendmmsg is available in 2.6.39. */
-#if __LINUX_KERNEL_VERSION >= 0x020627
-# define __ASSUME_SENDMMSG 1
+#if __LINUX_KERNEL_VERSION >= 0x050100 \
+ || __WORDSIZE == 64 \
+ || (defined __SYSCALL_WORDSIZE && __SYSCALL_WORDSIZE == 64)
+# define __ASSUME_TIME64_SYSCALLS 1
#endif
-/* getcpu is a syscall for x86-64 since 3.1. */
-#if defined __x86_64__ && __LINUX_KERNEL_VERSION >= 0x030100
-# define __ASSUME_GETCPU_SYSCALL 1
+/* 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
-/* 2.6.29 removed the XFS restricted_chown sysctl, so it is pointless looking
- for it in newer kernels. */
-#if __LINUX_KERNEL_VERSION >= 0x02061d
-# define __ASSUME_XFS_RESTRICTED_CHOWN 1
-#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 */
projects / thirdparty / glibc.git / blobdiff