sysdeps/unix/sysv/linux/kernel-features.h

   1 /* Set flags signalling availability of kernel features based on given
   2    kernel version number.
   3    Copyright (C) 1999-2018 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 /* This file must not contain any C code.  At least it must be protected
  21    to allow using the file also in assembler files.  */
  22
  23 #ifndef __LINUX_KERNEL_VERSION
  24 /* We assume the worst; all kernels should be supported.  */
  25 # define __LINUX_KERNEL_VERSION 0
  26 #endif
  27
  28 /* We assume for __LINUX_KERNEL_VERSION the same encoding used in
  29    linux/version.h.  I.e., the major, minor, and subminor all get a
  30    byte with the major number being in the highest byte.  This means
  31    we can do numeric comparisons.
  32
  33    In the following we will define certain symbols depending on
  34    whether the describes kernel feature is available in the kernel
  35    version given by __LINUX_KERNEL_VERSION.  We are not always exactly
  36    recording the correct versions in which the features were
  37    introduced.  If somebody cares these values can afterwards be
  38    corrected.  */
  39
  40 /* Some architectures use the socketcall multiplexer for some or all
  41    socket-related operations instead of separate syscalls.
  42    __ASSUME_SOCKETCALL is defined for such architectures.  */
  43
  44 /* The changed st_ino field appeared in 2.4.0-test6.  However, SH is lame,
  45    and still does not have a 64-bit inode field.  */
  46 #define __ASSUME_ST_INO_64_BIT          1
  47
  48 /* The statfs64 syscalls are available in 2.5.74 (but not for alpha).  */
  49 #define __ASSUME_STATFS64       1
  50
  51 /* pselect/ppoll were introduced just after 2.6.16-rc1.  On x86_64 and
  52    SH this appeared first in 2.6.19-rc1, on ia64 in 2.6.22-rc1.  */
  53 #define __ASSUME_PSELECT        1
  54
  55 /* The *at syscalls were introduced just after 2.6.16-rc1.  On PPC
  56    they were introduced in 2.6.17-rc1, on SH in 2.6.19-rc1.  */
  57 #define __ASSUME_ATFCTS 1
  58
  59 /* Support for inter-process robust mutexes was added in 2.6.17 (but
  60    some architectures lack futex_atomic_cmpxchg_inatomic in some
  61    configurations).  */
  62 #define __ASSUME_SET_ROBUST_LIST        1
  63
  64 /* Support for private futexes was added in 2.6.22.  */
  65 #define __ASSUME_PRIVATE_FUTEX  1
  66
  67 /* Support for various CLOEXEC and NONBLOCK flags was added in
  68    2.6.27.  */
  69 #define __ASSUME_IN_NONBLOCK    1
  70
  71 /* Support for the FUTEX_CLOCK_REALTIME flag was added in 2.6.29.  */
  72 #define __ASSUME_FUTEX_CLOCK_REALTIME   1
  73
  74 /* Support for preadv and pwritev was added in 2.6.30.  */
  75 #define __ASSUME_PREADV 1
  76 #define __ASSUME_PWRITEV        1
  77
  78 /* Support for sendmmsg functionality was added in 3.0.  */
  79 #define __ASSUME_SENDMMSG       1
  80
  81 /* On most architectures, most socket syscalls are supported for all
  82    supported kernel versions, but on some socketcall architectures
  83    separate syscalls were only added later.  */
  84 #define __ASSUME_SENDMSG_SYSCALL        1
  85 #define __ASSUME_RECVMSG_SYSCALL        1
  86 #define __ASSUME_ACCEPT_SYSCALL         1
  87 #define __ASSUME_CONNECT_SYSCALL        1
  88 #define __ASSUME_RECVFROM_SYSCALL       1
  89 #define __ASSUME_SENDTO_SYSCALL         1
  90 #define __ASSUME_ACCEPT4_SYSCALL        1
  91 #define __ASSUME_RECVMMSG_SYSCALL       1
  92 #define __ASSUME_SENDMMSG_SYSCALL       1
  93
  94 /* Support for SysV IPC through wired syscalls.  All supported architectures
  95    either support ipc syscall and/or all the ipc correspondent syscalls.  */
  96 #define __ASSUME_DIRECT_SYSVIPC_SYSCALLS        1
  97
  98 /* Support for p{read,write}v2 was added in 4.6.  However Linux default
  99    implementation does not assume the __ASSUME_* and instead use a fallback
 100    implementation based on p{read,write}v and returning an error for
 101    non supported flags.  */
 102
 103 /* Support for the execveat syscall was added in 3.19.  */
 104 #if __LINUX_KERNEL_VERSION >= 0x031300
 105 # define __ASSUME_EXECVEAT      1
 106 #endif
 107
 108 #if __LINUX_KERNEL_VERSION >= 0x040400
 109 # define __ASSUME_MLOCK2 1
 110 #endif
 111
 112 #if __LINUX_KERNEL_VERSION >= 0x040500
 113 # define __ASSUME_COPY_FILE_RANGE 1
 114 #endif
 115
 116 /* Support for clone call used on fork.  The signature varies across the
 117    architectures with current 4 different variants:
 118
 119    1. long int clone (unsigned long flags, unsigned long newsp,
 120                       int *parent_tidptr, unsigned long tls,
 121                       int *child_tidptr)
 122
 123    2. long int clone (unsigned long newsp, unsigned long clone_flags,
 124                       int *parent_tidptr, int * child_tidptr,
 125                       unsigned long tls)
 126
 127    3. long int clone (unsigned long flags, unsigned long newsp,
 128                       int stack_size, int *parent_tidptr,
 129                       int *child_tidptr, unsigned long tls)
 130
 131    4. long int clone (unsigned long flags, unsigned long newsp,
 132                       int *parent_tidptr, int *child_tidptr,
 133                       unsigned long tls)
 134
 135    The fourth variant is intended to be used as the default for newer ports,
 136    Also IA64 uses the third variant but with __NR_clone2 instead of
 137    __NR_clone.
 138
 139    The macros names to define the variant used for the architecture is
 140    similar to kernel:
 141
 142    - __ASSUME_CLONE_BACKWARDS: for variant 1.
 143    - __ASSUME_CLONE_BACKWARDS2: for variant 2 (s390).
 144    - __ASSUME_CLONE_BACKWARDS3: for variant 3 (microblaze).
 145    - __ASSUME_CLONE_DEFAULT: for variant 4.
 146    - __ASSUME_CLONE2: for clone2 with variant 3 (ia64).
 147    */
 148
 149 #define __ASSUME_CLONE_DEFAULT 1