- 根目录:
- include
- linux
- compiler.h
#ifndef __LINUX_COMPILER_H
#define __LINUX_COMPILER_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)))
#ifdef CONFIG_SPARSE_RCU_POINTER
# define __rcu __attribute__((noderef, address_space(4)))
#else
# define __rcu
#endif
extern void __chk_user_ptr(const volatile void __user *);
extern void __chk_io_ptr(const volatile void __iomem *);
#else
# define __user
# 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
#endif
/* Indirect macros required for expanded argument pasting, eg. __LINE__. */
#define ___PASTE(a,b) a##b
#define __PASTE(a,b) ___PASTE(a,b)
#ifdef __KERNEL__
#ifdef __GNUC__
#include <linux/compiler-gcc.h>
#endif
#define notrace __attribute__((no_instrument_function))
/* Intel compiler defines __GNUC__. So we will overwrite implementations
* coming from above header files here
*/
#ifdef __INTEL_COMPILER
# include <linux/compiler-intel.h>
#endif
/*
* Generic compiler-dependent macros required for kernel
* build go below this comment. Actual compiler/compiler version
* specific implementations come from the above header files
*/
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];
};
};
/*
* Note: DISABLE_BRANCH_PROFILING can be used by special lowlevel code
* to disable branch tracing on a per file basis.
*/
#if defined(CONFIG_TRACE_BRANCH_PROFILING) \
&& !defined(DISABLE_BRANCH_PROFILING) && !defined(__CHECKER__)
void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
#define likely_notrace(x) __builtin_expect(!!(x), 1)
#define unlikely_notrace(x) __builtin_expect(!!(x), 0)
#define __branch_check__(x, expect) ({ \
int ______r; \
static struct ftrace_branch_data \
__attribute__((__aligned__(4))) \
__attribute__((section("_ftrace_annotated_branch"))) \
______f = { \
.func = __func__, \
.file = __FILE__, \
.line = __LINE__, \
}; \
______r = likely_notrace(x); \
ftrace_likely_update(&______f, ______r, expect); \
______r; \
})
/*
* Using __builtin_constant_p(x) to ignore cases where the return
* value is always the same. This idea is taken from a similar patch
* written by Daniel Walker.
*/
# ifndef likely
# define likely(x) (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 1))
# endif
# ifndef unlikely
# define unlikely(x) (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 0))
# endif
#ifdef CONFIG_PROFILE_ALL_BRANCHES
/*
* "Define 'is'", Bill Clinton
* "Define 'if'", Steven Rostedt
*/
#define if(cond, ...) __trace_if( (cond , ## __VA_ARGS__) )
#define __trace_if(cond) \
if (__builtin_constant_p((cond)) ? !!(cond) : \
({ \
int ______r; \
static struct ftrace_branch_data \
__attribute__((__aligned__(4))) \
__attribute__((section("_ftrace_branch"))) \
______f = { \
.func = __func__, \
.file = __FILE__, \
.line = __LINE__, \
}; \
______r = !!(cond); \
______f.miss_hit[______r]++; \
______r; \
}))
#endif /* CONFIG_PROFILE_ALL_BRANCHES */
#else
# define likely(x) __builtin_expect(!!(x), 1)
# define unlikely(x) __builtin_expect(!!(x), 0)
#endif
/* Optimization barrier */
#ifndef barrier
# define barrier() __memory_barrier()
#endif
/* Unreachable code */
#ifndef unreachable
# define unreachable() do { } while (1)
#endif
#ifndef RELOC_HIDE
# define RELOC_HIDE(ptr, off) \
({ unsigned long __ptr; \
__ptr = (unsigned long) (ptr); \
(typeof(ptr)) (__ptr + (off)); })
#endif
#ifndef OPTIMIZER_HIDE_VAR
#define OPTIMIZER_HIDE_VAR(var) barrier()
#endif
/* Not-quite-unique ID. */
#ifndef __UNIQUE_ID
# define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __LINE__)
#endif
#endif /* __KERNEL__ */
#endif /* __ASSEMBLY__ */
#ifdef __KERNEL__
/*
* Allow us to mark functions as 'deprecated' and have gcc emit a nice
* warning for each use, in hopes of speeding the functions removal.
* Usage is:
* int __deprecated foo(void)
*/
#ifndef __deprecated
# define __deprecated /* unimplemented */
#endif
#ifdef MODULE
#define __deprecated_for_modules __deprecated
#else
#define __deprecated_for_modules
#endif
#ifndef __must_check
#define __must_check
#endif
#ifndef CONFIG_ENABLE_MUST_CHECK
#undef __must_check
#define __must_check
#endif
#ifndef CONFIG_ENABLE_WARN_DEPRECATED
#undef __deprecated
#undef __deprecated_for_modules
#define __deprecated
#define __deprecated_for_modules
#endif
/*
* Allow us to avoid 'defined but not used' warnings on functions and data,
* as well as force them to be emitted to the assembly file.
*
* As of gcc 3.4, static functions that are not marked with attribute((used))
* may be elided from the assembly file. As of gcc 3.4, static data not so
* marked will not be elided, but this may change in a future gcc version.
*
* NOTE: Because distributions shipped with a backported unit-at-a-time
* compiler in gcc 3.3, we must define __used to be __attribute__((used))
* for gcc >=3.3 instead of 3.4.
*
* In prior versions of gcc, such functions and data would be emitted, but
* would be warned about except with attribute((unused)).
*
* Mark functions that are referenced only in inline assembly as __used so
* the code is emitted even though it appears to be unreferenced.
*/
#ifndef __used
# define __used /* unimplemented */
#endif
#ifndef __maybe_unused
# define __maybe_unused /* unimplemented */
#endif
#ifndef __always_unused
# define __always_unused /* unimplemented */
#endif
#ifndef noinline
#define noinline
#endif
/*
* Rather then using noinline to prevent stack consumption, use
* noinline_for_stack instead. For documentation reasons.
*/
#define noinline_for_stack noinline
#ifndef __always_inline
#define __always_inline inline
#endif
#endif /* __KERNEL__ */
/*
* From the GCC manual:
*
* Many functions do not examine any values except their arguments,
* and have no effects except the return value. Basically this is
* just slightly more strict class than the `pure' attribute above,
* since function is not allowed to read global memory.
*
* Note that a function that has pointer arguments and examines the
* data pointed to must _not_ be declared `const'. Likewise, a
* function that calls a non-`const' function usually must not be
* `const'. It does not make sense for a `const' function to return
* `void'.
*/
#ifndef __attribute_const__
# define __attribute_const__ /* unimplemented */
#endif
/*
* Tell gcc if a function is cold. The compiler will assume any path
* directly leading to the call is unlikely.
*/
#ifndef __cold
#define __cold
#endif
/* Simple shorthand for a section definition */
#ifndef __section
# define __section(S) __attribute__ ((__section__(#S)))
#endif
#ifndef __visible
#define __visible
#endif
/* Are two types/vars the same type (ignoring qualifiers)? */
#ifndef __same_type
# define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
#endif
/* Is this type a native word size -- useful for atomic operations */
#ifndef __native_word
# define __native_word(t) (sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long))
#endif
/* Compile time object size, -1 for unknown */
#ifndef __compiletime_object_size
# define __compiletime_object_size(obj) -1
#endif
#ifndef __compiletime_warning
# define __compiletime_warning(message)
#endif
#ifndef __compiletime_error
# define __compiletime_error(message)
# define __compiletime_error_fallback(condition) \
do { ((void)sizeof(char[1 - 2 * condition])); } while (0)
#else
# define __compiletime_error_fallback(condition) do { } while (0)
#endif
#define __compiletime_assert(condition, msg, prefix, suffix) \
do { \
bool __cond = !(condition); \
extern void prefix ## suffix(void) __compiletime_error(msg); \
if (__cond) \
prefix ## suffix(); \
__compiletime_error_fallback(__cond); \
} while (0)
#define _compiletime_assert(condition, msg, prefix, suffix) \
__compiletime_assert(condition, msg, prefix, suffix)
/**
* compiletime_assert - break build and emit msg if condition is false
* @condition: a compile-time constant condition to check
* @msg: a message to emit if condition is false
*
* In tradition of POSIX assert, this macro will break the build if the
* supplied condition is *false*, emitting the supplied error message if the
* compiler has support to do so.
*/
#define compiletime_assert(condition, msg) \
_compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
#define compiletime_assert_atomic_type(t) \
compiletime_assert(__native_word(t), \
"Need native word sized stores/loads for atomicity.")
/*
* Prevent the compiler from merging or refetching accesses. The compiler
* is also forbidden from reordering successive instances of ACCESS_ONCE(),
* but only when the compiler is aware of some particular ordering. One way
* to make the compiler aware of ordering is to put the two invocations of
* ACCESS_ONCE() in different C statements.
*
* This macro does absolutely -nothing- to prevent the CPU from reordering,
* merging, or refetching absolutely anything at any time. Its main intended
* use is to mediate communication between process-level code and irq/NMI
* handlers, all running on the same CPU.
*/
#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
/* Ignore/forbid kprobes attach on very low level functions marked by this attribute: */
#ifdef CONFIG_KPROBES
# define __kprobes __attribute__((__section__(".kprobes.text")))
#else
# define __kprobes
#endif
#endif /* __LINUX_COMPILER_H */