linux-brain/include/linux/compiler_types.h

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/* SPDX-License-Identifier: GPL-2.0 */
linux/compiler.h: Split into compiler.h and compiler_types.h linux/compiler.h is included indirectly by linux/types.h via uapi/linux/types.h -> uapi/linux/posix_types.h -> linux/stddef.h -> uapi/linux/stddef.h and is needed to provide a proper definition of offsetof. Unfortunately, compiler.h requires a definition of smp_read_barrier_depends() for defining lockless_dereference() and soon for defining READ_ONCE(), which means that all users of READ_ONCE() will need to include asm/barrier.h to avoid splats such as: In file included from include/uapi/linux/stddef.h:1:0, from include/linux/stddef.h:4, from arch/h8300/kernel/asm-offsets.c:11: include/linux/list.h: In function 'list_empty': >> include/linux/compiler.h:343:2: error: implicit declaration of function 'smp_read_barrier_depends' [-Werror=implicit-function-declaration] smp_read_barrier_depends(); /* Enforce dependency ordering from x */ \ ^ A better alternative is to include asm/barrier.h in linux/compiler.h, but this requires a type definition for "bool" on some architectures (e.g. x86), which is defined later by linux/types.h. Type "bool" is also used directly in linux/compiler.h, so the whole thing is pretty fragile. This patch splits compiler.h in two: compiler_types.h contains type annotations, definitions and the compiler-specific parts, whereas compiler.h #includes compiler-types.h and additionally defines macros such as {READ,WRITE.ACCESS}_ONCE(). uapi/linux/stddef.h and linux/linkage.h are then moved over to include linux/compiler_types.h, which fixes the build for h8 and blackfin. Signed-off-by: Will Deacon <will.deacon@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1508840570-22169-2-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-24 19:22:46 +09:00
#ifndef __LINUX_COMPILER_TYPES_H
#define __LINUX_COMPILER_TYPES_H
#ifndef __ASSEMBLY__
#ifdef __CHECKER__
# define __user __attribute__((noderef, address_space(1)))
# define __kernel __attribute__((address_space(0)))
# define __safe __attribute__((safe))
# define __force __attribute__((force))
# define __nocast __attribute__((nocast))
# define __iomem __attribute__((noderef, address_space(2)))
# define __must_hold(x) __attribute__((context(x,1,1)))
# define __acquires(x) __attribute__((context(x,0,1)))
# define __releases(x) __attribute__((context(x,1,0)))
# define __acquire(x) __context__(x,1)
# define __release(x) __context__(x,-1)
# define __cond_lock(x,c) ((c) ? ({ __acquire(x); 1; }) : 0)
# define __percpu __attribute__((noderef, address_space(3)))
# define __rcu __attribute__((noderef, address_space(4)))
# define __private __attribute__((noderef))
extern void __chk_user_ptr(const volatile void __user *);
extern void __chk_io_ptr(const volatile void __iomem *);
# define ACCESS_PRIVATE(p, member) (*((typeof((p)->member) __force *) &(p)->member))
#else /* __CHECKER__ */
# ifdef STRUCTLEAK_PLUGIN
# define __user __attribute__((user))
# else
# define __user
# endif
# define __kernel
# define __safe
# define __force
# define __nocast
# define __iomem
# define __chk_user_ptr(x) (void)0
# define __chk_io_ptr(x) (void)0
# define __builtin_warning(x, y...) (1)
# define __must_hold(x)
# define __acquires(x)
# define __releases(x)
# define __acquire(x) (void)0
# define __release(x) (void)0
# define __cond_lock(x,c) (c)
# define __percpu
# define __rcu
# define __private
# define ACCESS_PRIVATE(p, member) ((p)->member)
#endif /* __CHECKER__ */
/* Indirect macros required for expanded argument pasting, eg. __LINE__. */
#define ___PASTE(a,b) a##b
#define __PASTE(a,b) ___PASTE(a,b)
#ifdef __KERNEL__
/* Attributes */
#include <linux/compiler_attributes.h>
/* Compiler specific macros. */
linux/compiler.h: Split into compiler.h and compiler_types.h linux/compiler.h is included indirectly by linux/types.h via uapi/linux/types.h -> uapi/linux/posix_types.h -> linux/stddef.h -> uapi/linux/stddef.h and is needed to provide a proper definition of offsetof. Unfortunately, compiler.h requires a definition of smp_read_barrier_depends() for defining lockless_dereference() and soon for defining READ_ONCE(), which means that all users of READ_ONCE() will need to include asm/barrier.h to avoid splats such as: In file included from include/uapi/linux/stddef.h:1:0, from include/linux/stddef.h:4, from arch/h8300/kernel/asm-offsets.c:11: include/linux/list.h: In function 'list_empty': >> include/linux/compiler.h:343:2: error: implicit declaration of function 'smp_read_barrier_depends' [-Werror=implicit-function-declaration] smp_read_barrier_depends(); /* Enforce dependency ordering from x */ \ ^ A better alternative is to include asm/barrier.h in linux/compiler.h, but this requires a type definition for "bool" on some architectures (e.g. x86), which is defined later by linux/types.h. Type "bool" is also used directly in linux/compiler.h, so the whole thing is pretty fragile. This patch splits compiler.h in two: compiler_types.h contains type annotations, definitions and the compiler-specific parts, whereas compiler.h #includes compiler-types.h and additionally defines macros such as {READ,WRITE.ACCESS}_ONCE(). uapi/linux/stddef.h and linux/linkage.h are then moved over to include linux/compiler_types.h, which fixes the build for h8 and blackfin. Signed-off-by: Will Deacon <will.deacon@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1508840570-22169-2-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-24 19:22:46 +09:00
#ifdef __clang__
#include <linux/compiler-clang.h>
#elif defined(__INTEL_COMPILER)
#include <linux/compiler-intel.h>
#elif defined(__GNUC__)
/* The above compilers also define __GNUC__, so order is important here. */
#include <linux/compiler-gcc.h>
#else
#error "Unknown compiler"
linux/compiler.h: Split into compiler.h and compiler_types.h linux/compiler.h is included indirectly by linux/types.h via uapi/linux/types.h -> uapi/linux/posix_types.h -> linux/stddef.h -> uapi/linux/stddef.h and is needed to provide a proper definition of offsetof. Unfortunately, compiler.h requires a definition of smp_read_barrier_depends() for defining lockless_dereference() and soon for defining READ_ONCE(), which means that all users of READ_ONCE() will need to include asm/barrier.h to avoid splats such as: In file included from include/uapi/linux/stddef.h:1:0, from include/linux/stddef.h:4, from arch/h8300/kernel/asm-offsets.c:11: include/linux/list.h: In function 'list_empty': >> include/linux/compiler.h:343:2: error: implicit declaration of function 'smp_read_barrier_depends' [-Werror=implicit-function-declaration] smp_read_barrier_depends(); /* Enforce dependency ordering from x */ \ ^ A better alternative is to include asm/barrier.h in linux/compiler.h, but this requires a type definition for "bool" on some architectures (e.g. x86), which is defined later by linux/types.h. Type "bool" is also used directly in linux/compiler.h, so the whole thing is pretty fragile. This patch splits compiler.h in two: compiler_types.h contains type annotations, definitions and the compiler-specific parts, whereas compiler.h #includes compiler-types.h and additionally defines macros such as {READ,WRITE.ACCESS}_ONCE(). uapi/linux/stddef.h and linux/linkage.h are then moved over to include linux/compiler_types.h, which fixes the build for h8 and blackfin. Signed-off-by: Will Deacon <will.deacon@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1508840570-22169-2-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-24 19:22:46 +09:00
#endif
compiler.h: Allow arch-specific asm/compiler.h We have a need to override the definition of barrier_before_unreachable() for MIPS, which means we either need to add architecture-specific code into linux/compiler-gcc.h or we need to allow the architecture to provide a header that can define the macro before the generic definition. The latter seems like the better approach. A straightforward approach to the per-arch header is to make use of asm-generic to provide a default empty header & adjust architectures which don't need anything specific to make use of that by adding the header to generic-y. Unfortunately this doesn't work so well due to commit 28128c61e08e ("kconfig.h: Include compiler types to avoid missed struct attributes") which caused linux/compiler_types.h to be included in the compilation of every C file via the -include linux/kconfig.h flag in c_flags. Because the -include flag is present for all C files we compile, we need the architecture-provided header to be present before any C files are compiled. If any C files can be compiled prior to the asm-generic header wrappers being generated then we hit a build failure due to missing header. Such cases do exist - one pointed out by the kbuild test robot is the compilation of arch/ia64/kernel/nr-irqs.c, which occurs as part of the archprepare target [1]. This leaves us with a few options: 1) Use generic-y & fix any build failures we find by enforcing ordering such that the asm-generic target occurs before any C compilation, such that linux/compiler_types.h can always include the generated asm-generic wrapper which in turn includes the empty asm-generic header. This would rely on us finding all the problematic cases - I don't know for sure that the ia64 issue is the only one. 2) Add an actual empty header to each architecture, so that we don't need the generated asm-generic wrapper. This seems messy. 3) Give up & add #ifdef CONFIG_MIPS or similar to linux/compiler_types.h. This seems messy too. 4) Include the arch header only when it's actually needed, removing the need for the asm-generic wrapper for all other architectures. This patch allows us to use approach 4, by including an asm/compiler.h header from linux/compiler_types.h after the inclusion of the compiler-specific linux/compiler-*.h header(s). We do this conditionally, only when CONFIG_HAVE_ARCH_COMPILER_H is selected, in order to avoid the need for asm-generic wrappers & the associated build ordering issue described above. The asm/compiler.h header is included after the generic linux/compiler-*.h header(s) for consistency with the way linux/compiler-intel.h & linux/compiler-clang.h are included after the linux/compiler-gcc.h header that they override. [1] https://lists.01.org/pipermail/kbuild-all/2018-August/051175.html Signed-off-by: Paul Burton <paul.burton@mips.com> Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com> Patchwork: https://patchwork.linux-mips.org/patch/20269/ Cc: Arnd Bergmann <arnd@arndb.de> Cc: James Hogan <jhogan@kernel.org> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-arch@vger.kernel.org Cc: linux-kbuild@vger.kernel.org Cc: linux-mips@linux-mips.org
2018-08-21 07:36:17 +09:00
/*
* Some architectures need to provide custom definitions of macros provided
* by linux/compiler-*.h, and can do so using asm/compiler.h. We include that
* conditionally rather than using an asm-generic wrapper in order to avoid
* build failures if any C compilation, which will include this file via an
* -include argument in c_flags, occurs prior to the asm-generic wrappers being
* generated.
*/
#ifdef CONFIG_HAVE_ARCH_COMPILER_H
#include <asm/compiler.h>
#endif
linux/compiler.h: Split into compiler.h and compiler_types.h linux/compiler.h is included indirectly by linux/types.h via uapi/linux/types.h -> uapi/linux/posix_types.h -> linux/stddef.h -> uapi/linux/stddef.h and is needed to provide a proper definition of offsetof. Unfortunately, compiler.h requires a definition of smp_read_barrier_depends() for defining lockless_dereference() and soon for defining READ_ONCE(), which means that all users of READ_ONCE() will need to include asm/barrier.h to avoid splats such as: In file included from include/uapi/linux/stddef.h:1:0, from include/linux/stddef.h:4, from arch/h8300/kernel/asm-offsets.c:11: include/linux/list.h: In function 'list_empty': >> include/linux/compiler.h:343:2: error: implicit declaration of function 'smp_read_barrier_depends' [-Werror=implicit-function-declaration] smp_read_barrier_depends(); /* Enforce dependency ordering from x */ \ ^ A better alternative is to include asm/barrier.h in linux/compiler.h, but this requires a type definition for "bool" on some architectures (e.g. x86), which is defined later by linux/types.h. Type "bool" is also used directly in linux/compiler.h, so the whole thing is pretty fragile. This patch splits compiler.h in two: compiler_types.h contains type annotations, definitions and the compiler-specific parts, whereas compiler.h #includes compiler-types.h and additionally defines macros such as {READ,WRITE.ACCESS}_ONCE(). uapi/linux/stddef.h and linux/linkage.h are then moved over to include linux/compiler_types.h, which fixes the build for h8 and blackfin. Signed-off-by: Will Deacon <will.deacon@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1508840570-22169-2-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-24 19:22:46 +09:00
struct ftrace_branch_data {
const char *func;
const char *file;
unsigned line;
union {
struct {
unsigned long correct;
unsigned long incorrect;
};
struct {
unsigned long miss;
unsigned long hit;
};
unsigned long miss_hit[2];
};
};
struct ftrace_likely_data {
struct ftrace_branch_data data;
unsigned long constant;
};
#ifdef CONFIG_ENABLE_MUST_CHECK
#define __must_check __attribute__((__warn_unused_result__))
#else
#define __must_check
#endif
#if defined(CC_USING_HOTPATCH)
#define notrace __attribute__((hotpatch(0, 0)))
#elif defined(CC_USING_PATCHABLE_FUNCTION_ENTRY)
#define notrace __attribute__((patchable_function_entry(0, 0)))
#else
#define notrace __attribute__((__no_instrument_function__))
#endif
/* Section for code which can't be instrumented at all */
#define noinstr \
noinline notrace __attribute((__section__(".noinstr.text")))
/*
* it doesn't make sense on ARM (currently the only user of __naked)
* to trace naked functions because then mcount is called without
* stack and frame pointer being set up and there is no chance to
* restore the lr register to the value before mcount was called.
*/
#define __naked __attribute__((__naked__)) notrace
#define __compiler_offsetof(a, b) __builtin_offsetof(a, b)
/*
* Force always-inline if the user requests it so via the .config.
* Prefer gnu_inline, so that extern inline functions do not emit an
* externally visible function. This makes extern inline behave as per gnu89
* semantics rather than c99. This prevents multiple symbol definition errors
* of extern inline functions at link time.
* A lot of inline functions can cause havoc with function tracing.
* Do not use __always_inline here, since currently it expands to inline again
* (which would break users of __always_inline).
*/
compiler: allow all arches to enable CONFIG_OPTIMIZE_INLINING Commit 60a3cdd06394 ("x86: add optimized inlining") introduced CONFIG_OPTIMIZE_INLINING, but it has been available only for x86. The idea is obviously arch-agnostic. This commit moves the config entry from arch/x86/Kconfig.debug to lib/Kconfig.debug so that all architectures can benefit from it. This can make a huge difference in kernel image size especially when CONFIG_OPTIMIZE_FOR_SIZE is enabled. For example, I got 3.5% smaller arm64 kernel for v5.1-rc1. dec file 18983424 arch/arm64/boot/Image.before 18321920 arch/arm64/boot/Image.after This also slightly improves the "Kernel hacking" Kconfig menu as e61aca5158a8 ("Merge branch 'kconfig-diet' from Dave Hansen') suggested; this config option would be a good fit in the "compiler option" menu. Link: http://lkml.kernel.org/r/20190423034959.13525-12-yamada.masahiro@socionext.com Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Borislav Petkov <bp@suse.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Boris Brezillon <bbrezillon@kernel.org> Cc: Brian Norris <computersforpeace@gmail.com> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Marek Vasut <marek.vasut@gmail.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Malaterre <malat@debian.org> Cc: Miquel Raynal <miquel.raynal@bootlin.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Richard Weinberger <richard@nod.at> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: Stefan Agner <stefan@agner.ch> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-15 07:42:25 +09:00
#if !defined(CONFIG_OPTIMIZE_INLINING)
#define inline inline __attribute__((__always_inline__)) __gnu_inline \
kbuild: allow Clang to find unused static inline functions for W=1 build GCC and Clang have different policy for -Wunused-function; GCC does not warn unused static inline functions at all whereas Clang does if they are defined in source files instead of included headers although it has been suppressed since commit abb2ea7dfd82 ("compiler, clang: suppress warning for unused static inline functions"). We often miss to delete unused functions where 'static inline' is used in *.c files since there is no tool to detect them. Unused code remains until somebody notices. For example, commit 075ddd75680f ("regulator: core: remove unused rdev_get_supply()"). Let's remove __maybe_unused from the inline macro to allow Clang to start finding unused static inline functions. For now, we do this only for W=1 build since it is not a good idea to sprinkle warnings for the normal build (e.g. 35 warnings for arch/x86/configs/x86_64_defconfig). My initial attempt was to add -Wno-unused-function for no W= build (https://lore.kernel.org/patchwork/patch/1120594/) Nathan Chancellor pointed out that would weaken Clang's checks since we would no longer get -Wunused-function without W=1. It is true GCC would catch unused static non-inline functions, but it would weaken Clang as a standalone compiler, at least. Hence, here is a counter implementation. The current problem is, W=... only controls compiler flags, which are globally effective. There is no way to address only 'static inline' functions. This commit defines KBUILD_EXTRA_WARN[123] corresponding to W=[123]. When KBUILD_EXTRA_WARN1 is defined, __maybe_unused is omitted from the 'inline' macro. The new macro __inline_maybe_unused makes the code a bit uglier, so I hope we can remove it entirely after fixing most of the warnings. If you contribute to code clean-up, please run "make CC=clang W=1" and check -Wunused-function warnings. You will find lots of unused functions. Some of them are false-positives because the call-sites are disabled by #ifdef. I do not like to abuse the inline keyword for suppressing unused-function warnings because it is intended to be a hint for the compiler optimization. I prefer #ifdef around the definition, or __maybe_unused if #ifdef would make the code too ugly. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Tested-by: Nathan Chancellor <natechancellor@gmail.com>
2019-09-07 11:52:36 +09:00
__inline_maybe_unused notrace
#else
#define inline inline __gnu_inline \
kbuild: allow Clang to find unused static inline functions for W=1 build GCC and Clang have different policy for -Wunused-function; GCC does not warn unused static inline functions at all whereas Clang does if they are defined in source files instead of included headers although it has been suppressed since commit abb2ea7dfd82 ("compiler, clang: suppress warning for unused static inline functions"). We often miss to delete unused functions where 'static inline' is used in *.c files since there is no tool to detect them. Unused code remains until somebody notices. For example, commit 075ddd75680f ("regulator: core: remove unused rdev_get_supply()"). Let's remove __maybe_unused from the inline macro to allow Clang to start finding unused static inline functions. For now, we do this only for W=1 build since it is not a good idea to sprinkle warnings for the normal build (e.g. 35 warnings for arch/x86/configs/x86_64_defconfig). My initial attempt was to add -Wno-unused-function for no W= build (https://lore.kernel.org/patchwork/patch/1120594/) Nathan Chancellor pointed out that would weaken Clang's checks since we would no longer get -Wunused-function without W=1. It is true GCC would catch unused static non-inline functions, but it would weaken Clang as a standalone compiler, at least. Hence, here is a counter implementation. The current problem is, W=... only controls compiler flags, which are globally effective. There is no way to address only 'static inline' functions. This commit defines KBUILD_EXTRA_WARN[123] corresponding to W=[123]. When KBUILD_EXTRA_WARN1 is defined, __maybe_unused is omitted from the 'inline' macro. The new macro __inline_maybe_unused makes the code a bit uglier, so I hope we can remove it entirely after fixing most of the warnings. If you contribute to code clean-up, please run "make CC=clang W=1" and check -Wunused-function warnings. You will find lots of unused functions. Some of them are false-positives because the call-sites are disabled by #ifdef. I do not like to abuse the inline keyword for suppressing unused-function warnings because it is intended to be a hint for the compiler optimization. I prefer #ifdef around the definition, or __maybe_unused if #ifdef would make the code too ugly. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Tested-by: Nathan Chancellor <natechancellor@gmail.com>
2019-09-07 11:52:36 +09:00
__inline_maybe_unused notrace
#endif
/*
* gcc provides both __inline__ and __inline as alternate spellings of
* the inline keyword, though the latter is undocumented. New kernel
* code should only use the inline spelling, but some existing code
* uses __inline__. Since we #define inline above, to ensure
* __inline__ has the same semantics, we need this #define.
*
* However, the spelling __inline is strictly reserved for referring
* to the bare keyword.
*/
#define __inline__ inline
kbuild: allow Clang to find unused static inline functions for W=1 build GCC and Clang have different policy for -Wunused-function; GCC does not warn unused static inline functions at all whereas Clang does if they are defined in source files instead of included headers although it has been suppressed since commit abb2ea7dfd82 ("compiler, clang: suppress warning for unused static inline functions"). We often miss to delete unused functions where 'static inline' is used in *.c files since there is no tool to detect them. Unused code remains until somebody notices. For example, commit 075ddd75680f ("regulator: core: remove unused rdev_get_supply()"). Let's remove __maybe_unused from the inline macro to allow Clang to start finding unused static inline functions. For now, we do this only for W=1 build since it is not a good idea to sprinkle warnings for the normal build (e.g. 35 warnings for arch/x86/configs/x86_64_defconfig). My initial attempt was to add -Wno-unused-function for no W= build (https://lore.kernel.org/patchwork/patch/1120594/) Nathan Chancellor pointed out that would weaken Clang's checks since we would no longer get -Wunused-function without W=1. It is true GCC would catch unused static non-inline functions, but it would weaken Clang as a standalone compiler, at least. Hence, here is a counter implementation. The current problem is, W=... only controls compiler flags, which are globally effective. There is no way to address only 'static inline' functions. This commit defines KBUILD_EXTRA_WARN[123] corresponding to W=[123]. When KBUILD_EXTRA_WARN1 is defined, __maybe_unused is omitted from the 'inline' macro. The new macro __inline_maybe_unused makes the code a bit uglier, so I hope we can remove it entirely after fixing most of the warnings. If you contribute to code clean-up, please run "make CC=clang W=1" and check -Wunused-function warnings. You will find lots of unused functions. Some of them are false-positives because the call-sites are disabled by #ifdef. I do not like to abuse the inline keyword for suppressing unused-function warnings because it is intended to be a hint for the compiler optimization. I prefer #ifdef around the definition, or __maybe_unused if #ifdef would make the code too ugly. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Tested-by: Nathan Chancellor <natechancellor@gmail.com>
2019-09-07 11:52:36 +09:00
/*
* GCC does not warn about unused static inline functions for -Wunused-function.
* Suppress the warning in clang as well by using __maybe_unused, but enable it
* for W=1 build. This will allow clang to find unused functions. Remove the
* __inline_maybe_unused entirely after fixing most of -Wunused-function warnings.
*/
#ifdef KBUILD_EXTRA_WARN1
#define __inline_maybe_unused
#else
#define __inline_maybe_unused __maybe_unused
#endif
/*
* Rather then using noinline to prevent stack consumption, use
* noinline_for_stack instead. For documentation reasons.
*/
#define noinline_for_stack noinline
linux/compiler.h: Split into compiler.h and compiler_types.h linux/compiler.h is included indirectly by linux/types.h via uapi/linux/types.h -> uapi/linux/posix_types.h -> linux/stddef.h -> uapi/linux/stddef.h and is needed to provide a proper definition of offsetof. Unfortunately, compiler.h requires a definition of smp_read_barrier_depends() for defining lockless_dereference() and soon for defining READ_ONCE(), which means that all users of READ_ONCE() will need to include asm/barrier.h to avoid splats such as: In file included from include/uapi/linux/stddef.h:1:0, from include/linux/stddef.h:4, from arch/h8300/kernel/asm-offsets.c:11: include/linux/list.h: In function 'list_empty': >> include/linux/compiler.h:343:2: error: implicit declaration of function 'smp_read_barrier_depends' [-Werror=implicit-function-declaration] smp_read_barrier_depends(); /* Enforce dependency ordering from x */ \ ^ A better alternative is to include asm/barrier.h in linux/compiler.h, but this requires a type definition for "bool" on some architectures (e.g. x86), which is defined later by linux/types.h. Type "bool" is also used directly in linux/compiler.h, so the whole thing is pretty fragile. This patch splits compiler.h in two: compiler_types.h contains type annotations, definitions and the compiler-specific parts, whereas compiler.h #includes compiler-types.h and additionally defines macros such as {READ,WRITE.ACCESS}_ONCE(). uapi/linux/stddef.h and linux/linkage.h are then moved over to include linux/compiler_types.h, which fixes the build for h8 and blackfin. Signed-off-by: Will Deacon <will.deacon@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1508840570-22169-2-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-24 19:22:46 +09:00
#endif /* __KERNEL__ */
#endif /* __ASSEMBLY__ */
linux/compiler.h: Split into compiler.h and compiler_types.h linux/compiler.h is included indirectly by linux/types.h via uapi/linux/types.h -> uapi/linux/posix_types.h -> linux/stddef.h -> uapi/linux/stddef.h and is needed to provide a proper definition of offsetof. Unfortunately, compiler.h requires a definition of smp_read_barrier_depends() for defining lockless_dereference() and soon for defining READ_ONCE(), which means that all users of READ_ONCE() will need to include asm/barrier.h to avoid splats such as: In file included from include/uapi/linux/stddef.h:1:0, from include/linux/stddef.h:4, from arch/h8300/kernel/asm-offsets.c:11: include/linux/list.h: In function 'list_empty': >> include/linux/compiler.h:343:2: error: implicit declaration of function 'smp_read_barrier_depends' [-Werror=implicit-function-declaration] smp_read_barrier_depends(); /* Enforce dependency ordering from x */ \ ^ A better alternative is to include asm/barrier.h in linux/compiler.h, but this requires a type definition for "bool" on some architectures (e.g. x86), which is defined later by linux/types.h. Type "bool" is also used directly in linux/compiler.h, so the whole thing is pretty fragile. This patch splits compiler.h in two: compiler_types.h contains type annotations, definitions and the compiler-specific parts, whereas compiler.h #includes compiler-types.h and additionally defines macros such as {READ,WRITE.ACCESS}_ONCE(). uapi/linux/stddef.h and linux/linkage.h are then moved over to include linux/compiler_types.h, which fixes the build for h8 and blackfin. Signed-off-by: Will Deacon <will.deacon@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1508840570-22169-2-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-24 19:22:46 +09:00
/*
* The below symbols may be defined for one or more, but not ALL, of the above
* compilers. We don't consider that to be an error, so set them to nothing.
* For example, some of them are for compiler specific plugins.
linux/compiler.h: Split into compiler.h and compiler_types.h linux/compiler.h is included indirectly by linux/types.h via uapi/linux/types.h -> uapi/linux/posix_types.h -> linux/stddef.h -> uapi/linux/stddef.h and is needed to provide a proper definition of offsetof. Unfortunately, compiler.h requires a definition of smp_read_barrier_depends() for defining lockless_dereference() and soon for defining READ_ONCE(), which means that all users of READ_ONCE() will need to include asm/barrier.h to avoid splats such as: In file included from include/uapi/linux/stddef.h:1:0, from include/linux/stddef.h:4, from arch/h8300/kernel/asm-offsets.c:11: include/linux/list.h: In function 'list_empty': >> include/linux/compiler.h:343:2: error: implicit declaration of function 'smp_read_barrier_depends' [-Werror=implicit-function-declaration] smp_read_barrier_depends(); /* Enforce dependency ordering from x */ \ ^ A better alternative is to include asm/barrier.h in linux/compiler.h, but this requires a type definition for "bool" on some architectures (e.g. x86), which is defined later by linux/types.h. Type "bool" is also used directly in linux/compiler.h, so the whole thing is pretty fragile. This patch splits compiler.h in two: compiler_types.h contains type annotations, definitions and the compiler-specific parts, whereas compiler.h #includes compiler-types.h and additionally defines macros such as {READ,WRITE.ACCESS}_ONCE(). uapi/linux/stddef.h and linux/linkage.h are then moved over to include linux/compiler_types.h, which fixes the build for h8 and blackfin. Signed-off-by: Will Deacon <will.deacon@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1508840570-22169-2-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-24 19:22:46 +09:00
*/
#ifndef __latent_entropy
# define __latent_entropy
#endif
#ifndef __randomize_layout
# define __randomize_layout __designated_init
#endif
#ifndef __no_randomize_layout
# define __no_randomize_layout
#endif
#ifndef randomized_struct_fields_start
# define randomized_struct_fields_start
# define randomized_struct_fields_end
#endif
#ifndef asm_volatile_goto
#define asm_volatile_goto(x...) asm goto(x)
#endif
#ifdef CONFIG_CC_HAS_ASM_INLINE
#define asm_inline asm __inline
#else
#define asm_inline asm
#endif
linux/compiler.h: Split into compiler.h and compiler_types.h linux/compiler.h is included indirectly by linux/types.h via uapi/linux/types.h -> uapi/linux/posix_types.h -> linux/stddef.h -> uapi/linux/stddef.h and is needed to provide a proper definition of offsetof. Unfortunately, compiler.h requires a definition of smp_read_barrier_depends() for defining lockless_dereference() and soon for defining READ_ONCE(), which means that all users of READ_ONCE() will need to include asm/barrier.h to avoid splats such as: In file included from include/uapi/linux/stddef.h:1:0, from include/linux/stddef.h:4, from arch/h8300/kernel/asm-offsets.c:11: include/linux/list.h: In function 'list_empty': >> include/linux/compiler.h:343:2: error: implicit declaration of function 'smp_read_barrier_depends' [-Werror=implicit-function-declaration] smp_read_barrier_depends(); /* Enforce dependency ordering from x */ \ ^ A better alternative is to include asm/barrier.h in linux/compiler.h, but this requires a type definition for "bool" on some architectures (e.g. x86), which is defined later by linux/types.h. Type "bool" is also used directly in linux/compiler.h, so the whole thing is pretty fragile. This patch splits compiler.h in two: compiler_types.h contains type annotations, definitions and the compiler-specific parts, whereas compiler.h #includes compiler-types.h and additionally defines macros such as {READ,WRITE.ACCESS}_ONCE(). uapi/linux/stddef.h and linux/linkage.h are then moved over to include linux/compiler_types.h, which fixes the build for h8 and blackfin. Signed-off-by: Will Deacon <will.deacon@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1508840570-22169-2-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-24 19:22:46 +09:00
/* Are two types/vars the same type (ignoring qualifiers)? */
#define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
linux/compiler.h: Split into compiler.h and compiler_types.h linux/compiler.h is included indirectly by linux/types.h via uapi/linux/types.h -> uapi/linux/posix_types.h -> linux/stddef.h -> uapi/linux/stddef.h and is needed to provide a proper definition of offsetof. Unfortunately, compiler.h requires a definition of smp_read_barrier_depends() for defining lockless_dereference() and soon for defining READ_ONCE(), which means that all users of READ_ONCE() will need to include asm/barrier.h to avoid splats such as: In file included from include/uapi/linux/stddef.h:1:0, from include/linux/stddef.h:4, from arch/h8300/kernel/asm-offsets.c:11: include/linux/list.h: In function 'list_empty': >> include/linux/compiler.h:343:2: error: implicit declaration of function 'smp_read_barrier_depends' [-Werror=implicit-function-declaration] smp_read_barrier_depends(); /* Enforce dependency ordering from x */ \ ^ A better alternative is to include asm/barrier.h in linux/compiler.h, but this requires a type definition for "bool" on some architectures (e.g. x86), which is defined later by linux/types.h. Type "bool" is also used directly in linux/compiler.h, so the whole thing is pretty fragile. This patch splits compiler.h in two: compiler_types.h contains type annotations, definitions and the compiler-specific parts, whereas compiler.h #includes compiler-types.h and additionally defines macros such as {READ,WRITE.ACCESS}_ONCE(). uapi/linux/stddef.h and linux/linkage.h are then moved over to include linux/compiler_types.h, which fixes the build for h8 and blackfin. Signed-off-by: Will Deacon <will.deacon@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1508840570-22169-2-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-24 19:22:46 +09:00
/* Is this type a native word size -- useful for atomic operations */
#define __native_word(t) \
(sizeof(t) == sizeof(char) || sizeof(t) == sizeof(short) || \
sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long))
/* Helpers for emitting diagnostics in pragmas. */
kbuild: add macro for controlling warnings to linux/compiler.h I have occasionally run into a situation where it would make sense to control a compiler warning from a source file rather than doing so from a Makefile using the $(cc-disable-warning, ...) or $(cc-option, ...) helpers. The approach here is similar to what glibc uses, using __diag() and related macros to encapsulate a _Pragma("GCC diagnostic ...") statement that gets turned into the respective "#pragma GCC diagnostic ..." by the preprocessor when the macro gets expanded. Like glibc, I also have an argument to pass the affected compiler version, but decided to actually evaluate that one. For now, this supports GCC_4_6, GCC_4_7, GCC_4_8, GCC_4_9, GCC_5, GCC_6, GCC_7, GCC_8 and GCC_9. Adding support for CLANG_5 and other interesting versions is straightforward here. GNU compilers starting with gcc-4.2 could support it in principle, but "#pragma GCC diagnostic push" was only added in gcc-4.6, so it seems simpler to not deal with those at all. The same versions show a large number of warnings already, so it seems easier to just leave it at that and not do a more fine-grained control for them. The use cases I found so far include: - turning off the gcc-8 -Wattribute-alias warning inside of the SYSCALL_DEFINEx() macro without having to do it globally. - Reducing the build time for a simple re-make after a change, once we move the warnings from ./Makefile and ./scripts/Makefile.extrawarn into linux/compiler.h - More control over the warnings based on other configurations, using preprocessor syntax instead of Makefile syntax. This should make it easier for the average developer to understand and change things. - Adding an easy way to turn the W=1 option on unconditionally for a subdirectory or a specific file. This has been requested by several developers in the past that want to have their subsystems W=1 clean. - Integrating clang better into the build systems. Clang supports more warnings than GCC, and we probably want to classify them as default, W=1, W=2 etc, but there are cases in which the warnings should be classified differently due to excessive false positives from one or the other compiler. - Adding a way to turn the default warnings into errors (e.g. using a new "make E=0" tag) while not also turning the W=1 warnings into errors. This patch for now just adds the minimal infrastructure in order to do the first of the list above. As the #pragma GCC diagnostic takes precedence over command line options, the next step would be to convert a lot of the individual Makefiles that set nonstandard options to use __diag() instead. [paul.burton@mips.com: - Rebase atop current master. - Add __diag_GCC, or more generally __diag_<compiler>, abstraction to avoid code outside of linux/compiler-gcc.h needing to duplicate knowledge about different GCC versions. - Add a comment argument to __diag_{ignore,warn,error} which isn't used in the expansion of the macros but serves to push people to document the reason for using them - per feedback from Kees Cook. - Translate severity to GCC-specific pragmas in linux/compiler-gcc.h rather than using GCC-specific in linux/compiler_types.h. - Drop all but GCC 8 macros, since we only need to define macros for versions that we need to introduce pragmas for, and as of this series that's just GCC 8. - Capitalize comments in linux/compiler-gcc.h to match the style of the rest of the file. - Line up macro definitions with tabs in linux/compiler-gcc.h.] Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Paul Burton <paul.burton@mips.com> Tested-by: Christophe Leroy <christophe.leroy@c-s.fr> Tested-by: Stafford Horne <shorne@gmail.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-06-20 05:14:56 +09:00
#ifndef __diag
#define __diag(string)
#endif
#ifndef __diag_GCC
#define __diag_GCC(version, severity, string)
#endif
#define __diag_push() __diag(push)
#define __diag_pop() __diag(pop)
#define __diag_ignore(compiler, version, option, comment) \
__diag_ ## compiler(version, ignore, option)
#define __diag_warn(compiler, version, option, comment) \
__diag_ ## compiler(version, warn, option)
#define __diag_error(compiler, version, option, comment) \
__diag_ ## compiler(version, error, option)
linux/compiler.h: Split into compiler.h and compiler_types.h linux/compiler.h is included indirectly by linux/types.h via uapi/linux/types.h -> uapi/linux/posix_types.h -> linux/stddef.h -> uapi/linux/stddef.h and is needed to provide a proper definition of offsetof. Unfortunately, compiler.h requires a definition of smp_read_barrier_depends() for defining lockless_dereference() and soon for defining READ_ONCE(), which means that all users of READ_ONCE() will need to include asm/barrier.h to avoid splats such as: In file included from include/uapi/linux/stddef.h:1:0, from include/linux/stddef.h:4, from arch/h8300/kernel/asm-offsets.c:11: include/linux/list.h: In function 'list_empty': >> include/linux/compiler.h:343:2: error: implicit declaration of function 'smp_read_barrier_depends' [-Werror=implicit-function-declaration] smp_read_barrier_depends(); /* Enforce dependency ordering from x */ \ ^ A better alternative is to include asm/barrier.h in linux/compiler.h, but this requires a type definition for "bool" on some architectures (e.g. x86), which is defined later by linux/types.h. Type "bool" is also used directly in linux/compiler.h, so the whole thing is pretty fragile. This patch splits compiler.h in two: compiler_types.h contains type annotations, definitions and the compiler-specific parts, whereas compiler.h #includes compiler-types.h and additionally defines macros such as {READ,WRITE.ACCESS}_ONCE(). uapi/linux/stddef.h and linux/linkage.h are then moved over to include linux/compiler_types.h, which fixes the build for h8 and blackfin. Signed-off-by: Will Deacon <will.deacon@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1508840570-22169-2-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-24 19:22:46 +09:00
#endif /* __LINUX_COMPILER_TYPES_H */