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authorArnd Bergmann <arnd@arndb.de>2018-02-21 14:45:20 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-02-28 10:19:41 +0100
commit0b82d316fa5b199125a22559fd457cf3100c34fc (patch)
tree7981f7c0df08e5b353628822970eaa9b27eb461a
parent6315213f0a788c7f08b02f88d1224e93f37d13f4 (diff)
Kbuild: always define endianess in kconfig.h
commit 101110f6271ce956a049250c907bc960030577f8 upstream. 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 e0d02285f16e ("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 4c97a0c8fee3 ("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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--include/linux/kconfig.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/kconfig.h b/include/linux/kconfig.h
index c5fd4ee776ba..dcde9471897d 100644
--- a/include/linux/kconfig.h
+++ b/include/linux/kconfig.h
@@ -4,6 +4,12 @@
#include <generated/autoconf.h>
+#ifdef CONFIG_CPU_BIG_ENDIAN
+#define __BIG_ENDIAN 4321
+#else
+#define __LITTLE_ENDIAN 1234
+#endif
+
#define __ARG_PLACEHOLDER_1 0,
#define __take_second_arg(__ignored, val, ...) val