msm-4.14/include/linux/linkage.h
Will Deacon a9772285a7 linux/compiler.h: Split into compiler.h and compiler_types.h
commit d15155824c5014803d91b829736d249c500bdda6 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-25 14:26:33 +01:00

114 lines
2.6 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_LINKAGE_H
#define _LINUX_LINKAGE_H
#include <linux/compiler_types.h>
#include <linux/stringify.h>
#include <linux/export.h>
#include <asm/linkage.h>
/* Some toolchains use other characters (e.g. '`') to mark new line in macro */
#ifndef ASM_NL
#define ASM_NL ;
#endif
#ifdef __cplusplus
#define CPP_ASMLINKAGE extern "C"
#else
#define CPP_ASMLINKAGE
#endif
#ifndef asmlinkage
#define asmlinkage CPP_ASMLINKAGE
#endif
#ifndef cond_syscall
#define cond_syscall(x) asm( \
".weak " VMLINUX_SYMBOL_STR(x) "\n\t" \
".set " VMLINUX_SYMBOL_STR(x) "," \
VMLINUX_SYMBOL_STR(sys_ni_syscall))
#endif
#ifndef SYSCALL_ALIAS
#define SYSCALL_ALIAS(alias, name) asm( \
".globl " VMLINUX_SYMBOL_STR(alias) "\n\t" \
".set " VMLINUX_SYMBOL_STR(alias) "," \
VMLINUX_SYMBOL_STR(name))
#endif
#define __page_aligned_data __section(.data..page_aligned) __aligned(PAGE_SIZE)
#define __page_aligned_bss __section(.bss..page_aligned) __aligned(PAGE_SIZE)
/*
* For assembly routines.
*
* Note when using these that you must specify the appropriate
* alignment directives yourself
*/
#define __PAGE_ALIGNED_DATA .section ".data..page_aligned", "aw"
#define __PAGE_ALIGNED_BSS .section ".bss..page_aligned", "aw"
/*
* This is used by architectures to keep arguments on the stack
* untouched by the compiler by keeping them live until the end.
* The argument stack may be owned by the assembly-language
* caller, not the callee, and gcc doesn't always understand
* that.
*
* We have the return value, and a maximum of six arguments.
*
* This should always be followed by a "return ret" for the
* protection to work (ie no more work that the compiler might
* end up needing stack temporaries for).
*/
/* Assembly files may be compiled with -traditional .. */
#ifndef __ASSEMBLY__
#ifndef asmlinkage_protect
# define asmlinkage_protect(n, ret, args...) do { } while (0)
#endif
#endif
#ifndef __ALIGN
#define __ALIGN .align 4,0x90
#define __ALIGN_STR ".align 4,0x90"
#endif
#ifdef __ASSEMBLY__
#ifndef LINKER_SCRIPT
#define ALIGN __ALIGN
#define ALIGN_STR __ALIGN_STR
#ifndef ENTRY
#define ENTRY(name) \
.globl name ASM_NL \
ALIGN ASM_NL \
name:
#endif
#endif /* LINKER_SCRIPT */
#ifndef WEAK
#define WEAK(name) \
.weak name ASM_NL \
name:
#endif
#ifndef END
#define END(name) \
.size name, .-name
#endif
/* If symbol 'name' is treated as a subroutine (gets called, and returns)
* then please use ENDPROC to mark 'name' as STT_FUNC for the benefit of
* static analysis tools such as stack depth analyzer.
*/
#ifndef ENDPROC
#define ENDPROC(name) \
.type name, @function ASM_NL \
END(name)
#endif
#endif
#endif