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101110f627
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>
73 lines
2.4 KiB
C
73 lines
2.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __LINUX_KCONFIG_H
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#define __LINUX_KCONFIG_H
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#include <generated/autoconf.h>
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#ifdef CONFIG_CPU_BIG_ENDIAN
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#define __BIG_ENDIAN 4321
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#else
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#define __LITTLE_ENDIAN 1234
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#endif
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#define __ARG_PLACEHOLDER_1 0,
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#define __take_second_arg(__ignored, val, ...) val
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/*
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* The use of "&&" / "||" is limited in certain expressions.
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* The following enable to calculate "and" / "or" with macro expansion only.
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*/
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#define __and(x, y) ___and(x, y)
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#define ___and(x, y) ____and(__ARG_PLACEHOLDER_##x, y)
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#define ____and(arg1_or_junk, y) __take_second_arg(arg1_or_junk y, 0)
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#define __or(x, y) ___or(x, y)
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#define ___or(x, y) ____or(__ARG_PLACEHOLDER_##x, y)
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#define ____or(arg1_or_junk, y) __take_second_arg(arg1_or_junk 1, y)
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/*
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* Helper macros to use CONFIG_ options in C/CPP expressions. Note that
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* these only work with boolean and tristate options.
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*/
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/*
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* Getting something that works in C and CPP for an arg that may or may
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* not be defined is tricky. Here, if we have "#define CONFIG_BOOGER 1"
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* we match on the placeholder define, insert the "0," for arg1 and generate
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* the triplet (0, 1, 0). Then the last step cherry picks the 2nd arg (a one).
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* When CONFIG_BOOGER is not defined, we generate a (... 1, 0) pair, and when
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* the last step cherry picks the 2nd arg, we get a zero.
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*/
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#define __is_defined(x) ___is_defined(x)
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#define ___is_defined(val) ____is_defined(__ARG_PLACEHOLDER_##val)
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#define ____is_defined(arg1_or_junk) __take_second_arg(arg1_or_junk 1, 0)
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/*
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* IS_BUILTIN(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y', 0
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* otherwise. For boolean options, this is equivalent to
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* IS_ENABLED(CONFIG_FOO).
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*/
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#define IS_BUILTIN(option) __is_defined(option)
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/*
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* IS_MODULE(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'm', 0
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* otherwise.
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*/
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#define IS_MODULE(option) __is_defined(option##_MODULE)
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/*
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* IS_REACHABLE(CONFIG_FOO) evaluates to 1 if the currently compiled
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* code can call a function defined in code compiled based on CONFIG_FOO.
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* This is similar to IS_ENABLED(), but returns false when invoked from
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* built-in code when CONFIG_FOO is set to 'm'.
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*/
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#define IS_REACHABLE(option) __or(IS_BUILTIN(option), \
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__and(IS_MODULE(option), __is_defined(MODULE)))
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/*
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* IS_ENABLED(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y' or 'm',
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* 0 otherwise.
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*/
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#define IS_ENABLED(option) __or(IS_BUILTIN(option), IS_MODULE(option))
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#endif /* __LINUX_KCONFIG_H */
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