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Arnd Bergmann 101110f627 Kbuild: always define endianess in kconfig.h
Build testing with LTO found a couple of files that get compiled
differently depending on whether asm/byteorder.h gets included early
enough or not.  In particular, include/asm-generic/qrwlock_types.h is
affected by this, but there are probably others as well.

The symptom is a series of LTO link time warnings, including these:

    net/netlabel/netlabel_unlabeled.h:223: error: type of 'netlbl_unlhsh_add' does not match original declaration [-Werror=lto-type-mismatch]
     int netlbl_unlhsh_add(struct net *net,
    net/netlabel/netlabel_unlabeled.c:377: note: 'netlbl_unlhsh_add' was previously declared here

    include/net/ipv6.h:360: error: type of 'ipv6_renew_options_kern' does not match original declaration [-Werror=lto-type-mismatch]
     ipv6_renew_options_kern(struct sock *sk,
    net/ipv6/exthdrs.c:1162: note: 'ipv6_renew_options_kern' was previously declared here

    net/core/dev.c:761: note: 'dev_get_by_name_rcu' was previously declared here
     struct net_device *dev_get_by_name_rcu(struct net *net, const char *name)
    net/core/dev.c:761: note: code may be misoptimized unless -fno-strict-aliasing is used

    drivers/gpu/drm/i915/i915_drv.h:3377: error: type of 'i915_gem_object_set_to_wc_domain' does not match original declaration [-Werror=lto-type-mismatch]
     i915_gem_object_set_to_wc_domain(struct drm_i915_gem_object *obj, bool write);
    drivers/gpu/drm/i915/i915_gem.c:3639: note: 'i915_gem_object_set_to_wc_domain' was previously declared here

    include/linux/debugfs.h:92:9: error: type of 'debugfs_attr_read' does not match original declaration [-Werror=lto-type-mismatch]
     ssize_t debugfs_attr_read(struct file *file, char __user *buf,
    fs/debugfs/file.c:318: note: 'debugfs_attr_read' was previously declared here

    include/linux/rwlock_api_smp.h:30: error: type of '_raw_read_unlock' does not match original declaration [-Werror=lto-type-mismatch]
     void __lockfunc _raw_read_unlock(rwlock_t *lock) __releases(lock);
    kernel/locking/spinlock.c:246:26: note: '_raw_read_unlock' was previously declared here

    include/linux/fs.h:3308:5: error: type of 'simple_attr_open' does not match original declaration [-Werror=lto-type-mismatch]
     int simple_attr_open(struct inode *inode, struct file *file,
    fs/libfs.c:795: note: 'simple_attr_open' was previously declared here

All of the above are caused by include/asm-generic/qrwlock_types.h
failing to include asm/byteorder.h after commit e0d02285f1
("locking/qrwlock: Use 'struct qrwlock' instead of 'struct __qrwlock'")
in linux-4.15.

Similar bugs may or may not exist in older kernels as well, but there is
no easy way to test those with link-time optimizations, and kernels
before 4.14 are harder to fix because they don't have Babu's patch
series

We had similar issues with CONFIG_ symbols in the past and ended up
always including the configuration headers though linux/kconfig.h.  This
works around the issue through that same file, defining either
__BIG_ENDIAN or __LITTLE_ENDIAN depending on CONFIG_CPU_BIG_ENDIAN,
which is now always set on all architectures since commit 4c97a0c8fe
("arch: define CPU_BIG_ENDIAN for all fixed big endian archs").

Link: http://lkml.kernel.org/r/20180202154104.1522809-2-arnd@arndb.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Babu Moger <babu.moger@amd.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-21 15:35:42 -08:00
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-02-19 11:58:19 -08:00
LICENSES LICENSES: Add MPL-1.1 license 2018-01-06 10:59:44 -07:00
arch Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-02-18 12:56:41 -08:00
block blk: optimization for classic polling 2018-02-13 09:12:04 -07:00
certs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2018-02-12 08:57:21 -08:00
drivers Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-02-19 11:58:19 -08:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs for-4.16-rc1-tag 2018-02-16 09:26:18 -08:00
include Kbuild: always define endianess in kconfig.h 2018-02-21 15:35:42 -08:00
init membarrier: Provide core serializing command, *_SYNC_CORE 2018-02-05 21:35:03 +01:00
ipc vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
kernel include/linux/sched/mm.h: re-inline mmdrop() 2018-02-21 15:35:42 -08:00
lib dma-direct: comment the dma_direct_free calling convention 2018-02-12 15:59:07 +00:00
mm mm: hide a #warning for COMPILE_TEST 2018-02-16 09:41:36 -08:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-02-19 11:58:19 -08:00
samples sample/bpf: fix erspan metadata 2018-02-06 11:32:49 -05:00
scripts Kbuild updates for v4.16 (2nd) 2018-02-09 19:32:41 -08:00
security vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
sound ALSA: hda/realtek: PCI quirk for Fujitsu U7x7 2018-02-14 12:02:26 +01:00
tools tools: fix cross-compile var clobbering 2018-02-21 15:35:42 -08:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore scripts/package: snap-pkg target 2017-12-13 00:00:18 +09:00
.mailmap mailmap: update Mark Yao's email address 2018-01-04 16:45:09 -08:00
COPYING
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS MAINTAINERS: Remove Richard Purdie from LED maintainers 2018-02-19 20:23:49 +01:00
Makefile Linux 4.16-rc2 2018-02-18 17:29:42 -08:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

README

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.