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* sysdeps/unix/sysv/linux/kernel-features.h (__ASSUME_VFORK_SYSCALL): Define for 2.4+ kernels. * sysdeps/unix/sysv/linux/i386/vfork.S: Optimize for kernels which are known to have the vfork syscall. Don't confuse the CPUs branch prediction unit by jumping to the return address.
235 lines
8.2 KiB
C
235 lines
8.2 KiB
C
/* Set flags signalling availability of kernel features based on given
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kernel version number.
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Copyright (C) 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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/* This file must not contain any C code. At least it must be protected
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to allow using the file also in assembler files. */
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#ifndef __LINUX_KERNEL_VERSION
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/* We assume the worst; all kernels should be supported. */
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# define __LINUX_KERNEL_VERSION 0
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#endif
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/* We assume for __LINUX_KERNEL_VERSION the same encoding used in
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linux/version.h. I.e., the major, minor, and subminor all get a
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byte with the major number being in the highest byte. This means
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we can do numeric comparisons.
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In the following we will define certain symbols depending on
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whether the describes kernel feature is available in the kernel
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version given by __LINUX_KERNEL_VERSION. We are not always exactly
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recording the correct versions in which the features were
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introduced. If somebody cares these values can afterwards be
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corrected. Most of the numbers here are set corresponding to
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2.2.0. */
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/* `getcwd' system call. */
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#if __LINUX_KERNEL_VERSION >= 131584
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# define __ASSUME_GETCWD_SYSCALL 1
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#endif
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/* Real-time signal became usable in 2.1.70. */
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#if __LINUX_KERNEL_VERSION >= 131398
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# define __ASSUME_REALTIME_SIGNALS 1
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#endif
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/* When were the `pread'/`pwrite' syscalls introduced? */
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#if __LINUX_KERNEL_VERSION >= 131584
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# define __ASSUME_PREAD_SYSCALL 1
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# define __ASSUME_PWRITE_SYSCALL 1
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#endif
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/* When was `poll' introduced? */
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#if __LINUX_KERNEL_VERSION >= 131584
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# define __ASSUME_POLL_SYSCALL 1
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#endif
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/* The `lchown' syscall was introduced in 2.1.80. */
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#if __LINUX_KERNEL_VERSION >= 131408
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# define __ASSUME_LCHOWN_SYSCALL 1
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#endif
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/* When did the `setresuid' sysall became available? */
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#if __LINUX_KERNEL_VERSION >= 131584 && !defined __sparc__
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# define __ASSUME_SETRESUID_SYSCALL 1
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#endif
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/* The SIOCGIFNAME ioctl is available starting with 2.1.50. */
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#if __LINUX_KERNEL_VERSION >= 131408
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# define __ASSUME_SIOCGIFNAME 1
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#endif
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/* On x86 another `getrlimit' syscall was added in 2.3.25. */
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#if __LINUX_KERNEL_VERSION >= 131865 && defined __i386__
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# define __ASSUME_NEW_GETRLIMIT_SYSCALL 1
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#endif
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/* On x86 the truncate64/ftruncate64 syscalls were introduced in 2.3.31. */
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#if __LINUX_KERNEL_VERSION >= 131871 && defined __i386__
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# define __ASSUME_TRUNCATE64_SYSCALL 1
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#endif
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/* On x86 the mmap2 syscall was introduced in 2.3.31. */
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#if __LINUX_KERNEL_VERSION >= 131871 && defined __i386__
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# define __ASSUME_MMAP2_SYSCALL 1
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#endif
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/* On x86 the stat64/lstat64/fstat64 syscalls were introduced in 2.3.34. */
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#if __LINUX_KERNEL_VERSION >= 131874 && defined __i386__
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# define __ASSUME_STAT64_SYSCALL 1
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#endif
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/* On sparc and ARM the truncate64/ftruncate64/mmap2/stat64/lstat64/fstat64
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syscalls were introduced in 2.3.35. */
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#if __LINUX_KERNEL_VERSION >= 131875 && (defined __sparc__ || defined __arm__)
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# define __ASSUME_TRUNCATE64_SYSCALL 1
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# define __ASSUME_MMAP2_SYSCALL 1
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# define __ASSUME_STAT64_SYSCALL 1
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#endif
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/* I know for sure that getrlimit are in 2.3.35 on powerpc. */
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#if __LINUX_KERNEL_VERSION >= 131875 && defined __powerpc__
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# define __ASSUME_NEW_GETRLIMIT_SYSCALL 1
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#endif
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/* I know for sure that these are in 2.3.35 on powerpc. But PowerPC64 does not
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support separate 64-bit syscalls, already 64-bit */
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#if __LINUX_KERNEL_VERSION >= 131875 && defined __powerpc__ \
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&& !defined __powerpc64__
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# define __ASSUME_TRUNCATE64_SYSCALL 1
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# define __ASSUME_STAT64_SYSCALL 1
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#endif
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/* Linux 2.3.39 introduced 32bit UID/GIDs. Some platforms had 32
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bit type all along. */
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#if __LINUX_KERNEL_VERSION >= 131879 || defined __powerpc__ || defined __mips__
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# define __ASSUME_32BITUIDS 1
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#endif
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/* Linux 2.3.39 sparc added setresuid. */
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#if __LINUX_KERNEL_VERSION >= 131879 && defined __sparc__
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# define __ASSUME_SETRESUID_SYSCALL 1
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#endif
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/* Linux 2.3.39 introduced IPC64. Except for powerpc. */
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#if __LINUX_KERNEL_VERSION >= 131879 && !defined __powerpc__
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# define __ASSUME_IPC64 1
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#endif
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/* mips platforms had IPC64 all along. */
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#if defined __mips__
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# define __ASSUME_IPC64 1
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#endif
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/* Linux 2.4.0 on PPC introduced a correct IPC64. But PowerPC64 does not
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support a separate 64-bit sys call, already 64-bit */
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#if __LINUX_KERNEL_VERSION >= 132096 && defined __powerpc__ \
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&& !defined __powerpc64__
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# define __ASSUME_IPC64 1
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#endif
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/* We can use the LDTs for threading with Linux 2.3.99 and newer. */
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#if __LINUX_KERNEL_VERSION >= 131939
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# define __ASSUME_LDT_WORKS 1
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#endif
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/* The changed st_ino field appeared in 2.4.0-test6. But we cannot
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distinguish this version from other 2.4.0 releases. Therefore play
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save and assume it available is for 2.4.1 and up. */
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#if __LINUX_KERNEL_VERSION >= 132097
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# define __ASSUME_ST_INO_64_BIT 1
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#endif
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/* To support locking of large files a new fcntl() syscall was introduced
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in 2.4.0-test7. We test for 2.4.1 for the earliest version we know
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the syscall is available. */
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#if __LINUX_KERNEL_VERSION >= 132097 && (defined __i386__ || defined __sparc__)
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# define __ASSUME_FCNTL64 1
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#endif
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/* Arm got fcntl64 in 2.4.4, PowerPC and SH have it also in 2.4.4 (I
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don't know when it got introduced). But PowerPC64 does not support
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separate FCNTL64 call, FCNTL is already 64-bit */
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#if __LINUX_KERNEL_VERSION >= 132100 \
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&& (defined __arm__ || defined __powerpc__ || defined __sh__) \
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&& !defined __powerpc64__
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# define __ASSUME_FCNTL64 1
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#endif
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/* The getdents64 syscall was introduced in 2.4.0-test7. We test for
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2.4.1 for the earliest version we know the syscall is available. */
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#if __LINUX_KERNEL_VERSION >= 132097
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# define __ASSUME_GETDENTS64_SYSCALL 1
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#endif
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/* When did O_DIRECTORY became available? Early in 2.3 but when?
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Be safe, use 2.3.99. */
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#if __LINUX_KERNEL_VERSION >= 131939
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# define __ASSUME_O_DIRECTORY 1
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#endif
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/* Starting with one of the 2.4.0 pre-releases the Linux kernel passes
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up the page size information. */
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#if __LINUX_KERNEL_VERSION >= 132097
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# define __ASSUME_AT_PAGESIZE 1
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#endif
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/* Starting with at least 2.4.0 the kernel passes the uid/gid unconditionally
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up to the child. */
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#if __LINUX_KERNEL_VERSION >= 132097
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# define __ASSUME_AT_XID 1
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#endif
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/* Starting with 2.4.5 kernels PPC passes the AUXV in the standard way. */
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#if __LINUX_KERNEL_VERSION >= (132096+5) && defined __powerpc__
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# define __ASSUME_STD_AUXV 1
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#endif
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/* Starting with 2.4.5 kernels the mmap2 syscall made it into the official
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kernel. But PowerPC64 does not support a separate MMAP2 call. */
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#if __LINUX_KERNEL_VERSION >= (132096+5) && defined __powerpc__ \
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&& !defined __powerpc64__
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# define __ASSUME_MMAP2_SYSCALL 1
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#endif
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/* On x86, the set_thread_area syscall was introduced in 2.5.29, but its
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semantics was changed in 2.5.30, and again after 2.5.31. */
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#if __LINUX_KERNEL_VERSION >= 132384 && defined __i386__
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# define __ASSUME_SET_THREAD_AREA_SYSCALL 1
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#endif
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/* The vfork syscall on x86 was definitely available in 2.4. */
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#if __LINUX_KERNEL_VERSION >= 132097 && defined __i386__
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# define __ASSUME_VFORK_SYSCALL 1
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#endif
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/* There are an infinite number of PA-RISC kernel versions numbered
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2.4.0. But they've not really been released as such. We require
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and expect the final version here. */
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#ifdef __hppa__
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# define __ASSUME_32BITUIDS 1
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# define __ASSUME_TRUNCATE64_SYSCALL 1
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# define __ASSUME_MMAP2_SYSCALL 1
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# define __ASSUME_STAT64_SYSCALL 1
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# define __ASSUME_IPC64 1
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# define __ASSUME_ST_INO_64_BIT 1
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# define __ASSUME_FCNTL64 1
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# define __ASSUME_GETDENTS64_SYSCALL 1
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#endif
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