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glibc/sysdeps/unix/sysv/linux/kernel-features.h
Joseph Myers 646ce7e0be Remove __ASSUME_ST_INO_64_BIT. 
kernel-features.h has a macro __ASSUME_ST_INO_64_BIT, with a comment
"However, SH is lame, and still does not have a 64-bit inode field.".

The macro is, in fact, defined to 0 by Alpha as well as SH.  The Alpha
case is, however, trivially useless: none of the files that test
__ASSUME_ST_INO_64_BIT are built for Alpha (which gained kernel
support for stat64 syscalls, with a 64-bit st_ino field, in Linux
2.6.4; the define to 0 for Alpha in glibc predates that).

The SH kernel gained support for a 64-bit st_ino in struct stat64 in
commit 760bcb1deec13c50e20399c84cb6a8ea41cc2820 ("sh: Fix fstatat64()
syscall."), which is in Linux 2.6.22 and later.  So the redefinition
of __ASSUME_ST_INO_64_BIT to 0 is of no use for SH either; three of
the files testing it do so immediately after a stat64-family syscall
has been used, which will always have set the 64-bit st_ino correctly
(in addition to the 32-bit __st_ino), while the relevant code
__xstat32_conv executes only after such a syscall in the function
calling __xstat32_conv.

Thus this patch removes __ASSUME_ST_INO_64_BIT and code testing it.
Removing the useless [!__ASSUME_ST_INO_64_BIT] code in __xstat32_conv
renders the [_HAVE_STAT64___ST_INO] and [!_HAVE_STAT64___ST_INO] cases
around it identical, so that conditional is also removed.

Tested compilation with build-many-glibcs.py for its Alpha and SH
configurations; also ran the glibc testsuite for x86_64 and x86.

	* sysdeps/unix/sysv/linux/kernel-features.h
	(__ASSUME_ST_INO_64_BIT): Remove macro definition.
	* sysdeps/unix/sysv/linux/alpha/kernel-features.h
	(__ASSUME_ST_INO_64_BIT): Do not undefine and define.
	* sysdeps/unix/sysv/linux/sh/kernel-features.h
	(__ASSUME_ST_INO_64_BIT): Likewise.
	* sysdeps/unix/sysv/linux/fxstat64.c: Do not include
	<kernel-features.h>.
	(___fxstat64) [_HAVE_STAT64___ST_INO && !__ASSUME_ST_INO_64_BIT]:
	Remove conditional code.
	* sysdeps/unix/sysv/linux/lxstat64.c: Do not include
	<kernel-features.h>.
	(___lxstat64) [_HAVE_STAT64___ST_INO && !__ASSUME_ST_INO_64_BIT]:
	Remove conditional code.
	* sysdeps/unix/sysv/linux/xstat64.c: Do not include
	<kernel-features.h>.
	(___xstat64) [_HAVE_STAT64___ST_INO && !__ASSUME_ST_INO_64_BIT]:
	Remove conditional code.
	* sysdeps/unix/sysv/linux/xstatconv.c: Do not include
	<kernel-features.h>.
	(__xstat32_conv) [_HAVE_STAT64___ST_INO]: Remove conditional code.
	[!_HAVE_STAT64___ST_INO]: Make code unconditional.
2018-12-18 13:35:39 +00:00

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/* Set flags signalling availability of kernel features based on given
kernel version number.
Copyright (C) 1999-2018 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
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
<http://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_VERSION
/* We assume the worst; all kernels should be supported. */
# define __LINUX_KERNEL_VERSION 0
#endif
/* We assume for __LINUX_KERNEL_VERSION the same encoding used in
linux/version.h. I.e., the major, minor, and subminor all get a
byte with the major number being in the highest byte. This means
we can do numeric comparisons.
In the following we will define certain symbols depending on
whether the describes kernel feature is available in the kernel
version given by __LINUX_KERNEL_VERSION. We are not always exactly
recording the correct versions in which the features were
introduced. If somebody cares these values can afterwards be
corrected. */
/* The statfs64 syscalls are available in 2.5.74 (but not for alpha). */
#define __ASSUME_STATFS64 1
/* 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
/* 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). */
#define __ASSUME_SET_ROBUST_LIST 1
/* Support for various CLOEXEC and NONBLOCK flags was added in
2.6.27. */
#define __ASSUME_IN_NONBLOCK 1
/* Support for the FUTEX_CLOCK_REALTIME flag was added in 2.6.29. */
#define __ASSUME_FUTEX_CLOCK_REALTIME 1
/* Support for preadv and pwritev was added in 2.6.30. */
#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
/* 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
#if __LINUX_KERNEL_VERSION >= 0x040500
# define __ASSUME_COPY_FILE_RANGE 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
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