[deliverable/linux.git] / 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 /* CONFIG_SPARSE_RCU_POINTER */
# define __rcu
#endif /* CONFIG_SPARSE_RCU_POINTER */
# 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__ */
# 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
# 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__

#ifdef __GNUC__
#include <linux/compiler-gcc.h>
#endif

#if defined(CC_USING_HOTPATCH) && !defined(__CHECKER__)
#define notrace __attribute__((hotpatch(0,0)))
#else
#define notrace __attribute__((no_instrument_function))
#endif

/* Intel compiler defines __GNUC__. So we will overwrite implementations
 * coming from above header files here
 */
#ifdef __INTEL_COMPILER
# include <linux/compiler-intel.h>
#endif

/* Clang compiler defines __GNUC__. So we will overwrite implementations
 * coming from above header files here
 */
#ifdef __clang__
#include <linux/compiler-clang.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

#ifndef barrier_data
# define barrier_data(ptr) 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

#include <uapi/linux/types.h>

#define __READ_ONCE_SIZE						\
({									\
	switch (size) {							\
	case 1: *(__u8 *)res = *(volatile __u8 *)p; break;		\
	case 2: *(__u16 *)res = *(volatile __u16 *)p; break;		\
	case 4: *(__u32 *)res = *(volatile __u32 *)p; break;		\
	case 8: *(__u64 *)res = *(volatile __u64 *)p; break;		\
	default:							\
		barrier();						\
		__builtin_memcpy((void *)res, (const void *)p, size);	\
		barrier();						\
	}								\
})

static __always_inline
void __read_once_size(const volatile void *p, void *res, int size)
{
	__READ_ONCE_SIZE;
}

#ifdef CONFIG_KASAN
/*
 * This function is not 'inline' because __no_sanitize_address confilcts
 * with inlining. Attempt to inline it may cause a build failure.
 * 	https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368
 * '__maybe_unused' allows us to avoid defined-but-not-used warnings.
 */
static __no_sanitize_address __maybe_unused
void __read_once_size_nocheck(const volatile void *p, void *res, int size)
{
	__READ_ONCE_SIZE;
}
#else
static __always_inline
void __read_once_size_nocheck(const volatile void *p, void *res, int size)
{
	__READ_ONCE_SIZE;
}
#endif

static __always_inline void __write_once_size(volatile void *p, void *res, int size)
{
	switch (size) {
	case 1: *(volatile __u8 *)p = *(__u8 *)res; break;
	case 2: *(volatile __u16 *)p = *(__u16 *)res; break;
	case 4: *(volatile __u32 *)p = *(__u32 *)res; break;
	case 8: *(volatile __u64 *)p = *(__u64 *)res; break;
	default:
		barrier();
		__builtin_memcpy((void *)p, (const void *)res, size);
		barrier();
	}
}

/*
 * Prevent the compiler from merging or refetching reads or writes. The
 * compiler is also forbidden from reordering successive instances of
 * READ_ONCE, WRITE_ONCE and ACCESS_ONCE (see below), 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 READ_ONCE,
 * WRITE_ONCE or ACCESS_ONCE() in different C statements.
 *
 * In contrast to ACCESS_ONCE these two macros will also work on aggregate
 * data types like structs or unions. If the size of the accessed data
 * type exceeds the word size of the machine (e.g., 32 bits or 64 bits)
 * READ_ONCE() and WRITE_ONCE() will fall back to memcpy(). There's at
 * least two memcpy()s: one for the __builtin_memcpy() and then one for
 * the macro doing the copy of variable - '__u' allocated on the stack.
 *
 * Their two major use cases are: (1) Mediating communication between
 * process-level code and irq/NMI handlers, all running on the same CPU,
 * and (2) Ensuring that the compiler does not  fold, spindle, or otherwise
 * mutilate accesses that either do not require ordering or that interact
 * with an explicit memory barrier or atomic instruction that provides the
 * required ordering.
 */

#define __READ_ONCE(x, check)						\
({									\
	union { typeof(x) __val; char __c[1]; } __u;			\
	if (check)							\
		__read_once_size(&(x), __u.__c, sizeof(x));		\
	else								\
		__read_once_size_nocheck(&(x), __u.__c, sizeof(x));	\
	__u.__val;							\
})
#define READ_ONCE(x) __READ_ONCE(x, 1)

/*
 * Use READ_ONCE_NOCHECK() instead of READ_ONCE() if you need
 * to hide memory access from KASAN.
 */
#define READ_ONCE_NOCHECK(x) __READ_ONCE(x, 0)

#define WRITE_ONCE(x, val) \
({							\
	union { typeof(x) __val; char __c[1]; } __u =	\
		{ .__val = (__force typeof(x)) (val) }; \
	__write_once_size(&(x), __u.__c, sizeof(x));	\
	__u.__val;					\
})

#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

#ifndef __malloc
#define __malloc
#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

/*
 * Assume alignment of return value.
 */
#ifndef __assume_aligned
#define __assume_aligned(a, ...)
#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(char) || sizeof(t) == sizeof(short) || 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)
/*
 * Sparse complains of variable sized arrays due to the temporary variable in
 * __compiletime_assert. Unfortunately we can't just expand it out to make
 * sparse see a constant array size without breaking compiletime_assert on old
 * versions of GCC (e.g. 4.2.4), so hide the array from sparse altogether.
 */
# ifndef __CHECKER__
#  define __compiletime_error_fallback(condition) \
	do { ((void)sizeof(char[1 - 2 * condition])); } while (0)
# endif
#endif
#ifndef __compiletime_error_fallback
# 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.
 *
 * ACCESS_ONCE will only work on scalar types. For union types, ACCESS_ONCE
 * on a union member will work as long as the size of the member matches the
 * size of the union and the size is smaller than word size.
 *
 * The major use cases of ACCESS_ONCE used to be (1) Mediating communication
 * between process-level code and irq/NMI handlers, all running on the same CPU,
 * and (2) Ensuring that the compiler does not  fold, spindle, or otherwise
 * mutilate accesses that either do not require ordering or that interact
 * with an explicit memory barrier or atomic instruction that provides the
 * required ordering.
 *
 * If possible use READ_ONCE()/WRITE_ONCE() instead.
 */
#define __ACCESS_ONCE(x) ({ \
	 __maybe_unused typeof(x) __var = (__force typeof(x)) 0; \
	(volatile typeof(x) *)&(x); })
#define ACCESS_ONCE(x) (*__ACCESS_ONCE(x))

/**
 * lockless_dereference() - safely load a pointer for later dereference
 * @p: The pointer to load
 *
 * Similar to rcu_dereference(), but for situations where the pointed-to
 * object's lifetime is managed by something other than RCU.  That
 * "something other" might be reference counting or simple immortality.
 *
 * The seemingly unused variable ___typecheck_p validates that @p is
 * indeed a pointer type by using a pointer to typeof(*p) as the type.
 * Taking a pointer to typeof(*p) again is needed in case p is void *.
 */
#define lockless_dereference(p) \
({ \
	typeof(p) _________p1 = READ_ONCE(p); \
	typeof(*(p)) *___typecheck_p __maybe_unused; \
	smp_read_barrier_depends(); /* Dependency order vs. p above. */ \
	(_________p1); \
})

/* Ignore/forbid kprobes attach on very low level functions marked by this attribute: */
#ifdef CONFIG_KPROBES
# define __kprobes	__attribute__((__section__(".kprobes.text")))
# define nokprobe_inline	__always_inline
#else
# define __kprobes
# define nokprobe_inline	inline
#endif
#endif /* __LINUX_COMPILER_H */
Commit	Line	Data
1da177e4 LT	1	#ifndef __LINUX_COMPILER_H
	2	#define __LINUX_COMPILER_H
	3
	4	#ifndef __ASSEMBLY__
	5
	6	#ifdef __CHECKER__
	7	# define __user __attribute__((noderef, address_space(1)))
e0fdb0e0	8	# define __kernel __attribute__((address_space(0)))
1da177e4 LT	9	# define __safe __attribute__((safe))
	10	# define __force __attribute__((force))
	11	# define __nocast __attribute__((nocast))
	12	# define __iomem __attribute__((noderef, address_space(2)))
8529091e	13	# define __must_hold(x) __attribute__((context(x,1,1)))
c902e0a0 JT	14	# define __acquires(x) __attribute__((context(x,0,1)))
	15	# define __releases(x) __attribute__((context(x,1,0)))
	16	# define __acquire(x) __context__(x,1)
	17	# define __release(x) __context__(x,-1)
dcc8e559	18	# define __cond_lock(x,c) ((c) ? ({ __acquire(x); 1; }) : 0)
e0fdb0e0	19	# define __percpu __attribute__((noderef, address_space(3)))
ca5ecddf PM	20	#ifdef CONFIG_SPARSE_RCU_POINTER
ca5ecddf PM	21	# define __rcu __attribute__((noderef, address_space(4)))
ad315455	22	#else /* CONFIG_SPARSE_RCU_POINTER */
71d1d5c7	23	# define __rcu
ad315455 BF	24	#endif /* CONFIG_SPARSE_RCU_POINTER */
ad315455 BF	25	# define __private __attribute__((noderef))
c47ffe3d AV	26	extern void __chk_user_ptr(const volatile void __user *);
c47ffe3d AV	27	extern void __chk_io_ptr(const volatile void __iomem *);
ad315455 BF	28	# define ACCESS_PRIVATE(p, member) (((typeof((p)->member) __force ) &(p)->member))
ad315455 BF	29	#else /* __CHECKER__ */
1da177e4 LT	30	# define __user
	31	# define __kernel
	32	# define __safe
	33	# define __force
	34	# define __nocast
	35	# define __iomem
	36	# define __chk_user_ptr(x) (void)0
	37	# define __chk_io_ptr(x) (void)0
	38	# define __builtin_warning(x, y...) (1)
8529091e	39	# define __must_hold(x)
1da177e4 LT	40	# define __acquires(x)
	41	# define __releases(x)
	42	# define __acquire(x) (void)0
	43	# define __release(x) (void)0
dcc8e559	44	# define __cond_lock(x,c) (c)
e0fdb0e0	45	# define __percpu
71d1d5c7	46	# define __rcu
ad315455 BF	47	# define __private
	48	# define ACCESS_PRIVATE(p, member) ((p)->member)
	49	#endif /* __CHECKER__ */
1da177e4	50
6f33d587 RR	51	/* Indirect macros required for expanded argument pasting, eg. __LINE__. */
	52	#define ___PASTE(a,b) a##b
	53	#define __PASTE(a,b) ___PASTE(a,b)
	54
1da177e4 LT	55	#ifdef __KERNEL__
1da177e4 LT	56
f153b821 LT	57	#ifdef __GNUC__
f153b821 LT	58	#include <linux/compiler-gcc.h>
1da177e4 LT	59	#endif
1da177e4 LT	60
0c5a69f4	61	#if defined(CC_USING_HOTPATCH) && !defined(__CHECKER__)
61f55214 HC	62	#define notrace __attribute__((hotpatch(0,0)))
61f55214 HC	63	#else
28614889	64	#define notrace __attribute__((no_instrument_function))
61f55214	65	#endif
28614889	66
1da177e4 LT	67	/* Intel compiler defines __GNUC__. So we will overwrite implementations
	68	* coming from above header files here
	69	*/
	70	#ifdef __INTEL_COMPILER
	71	# include <linux/compiler-intel.h>
	72	#endif
	73
565cbdc2 MC	74	/* Clang compiler defines __GNUC__. So we will overwrite implementations
	75	* coming from above header files here
	76	*/
	77	#ifdef __clang__
	78	#include <linux/compiler-clang.h>
	79	#endif
	80
1da177e4 LT	81	/*
	82	* Generic compiler-dependent macros required for kernel
	83	* build go below this comment. Actual compiler/compiler version
	84	* specific implementations come from the above header files
	85	*/
	86
2ed84eeb	87	struct ftrace_branch_data {
1f0d69a9 SR	88	const char *func;
	89	const char *file;
	90	unsigned line;
2bcd521a SR	91	union {
	92	struct {
	93	unsigned long correct;
	94	unsigned long incorrect;
	95	};
	96	struct {
	97	unsigned long miss;
	98	unsigned long hit;
	99	};
97e7e4f3	100	unsigned long miss_hit[2];
2bcd521a	101	};
1f0d69a9	102	};
2ed84eeb SR	103
	104	/*
	105	* Note: DISABLE_BRANCH_PROFILING can be used by special lowlevel code
	106	* to disable branch tracing on a per file basis.
	107	*/
d9ad8bc0 BVA	108	#if defined(CONFIG_TRACE_BRANCH_PROFILING) \
d9ad8bc0 BVA	109	&& !defined(DISABLE_BRANCH_PROFILING) && !defined(__CHECKER__)
2ed84eeb	110	void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
1f0d69a9 SR	111
	112	#define likely_notrace(x) __builtin_expect(!!(x), 1)
	113	#define unlikely_notrace(x) __builtin_expect(!!(x), 0)
	114
45b79749	115	#define __branch_check__(x, expect) ({ \
1f0d69a9	116	int ______r; \
2ed84eeb	117	static struct ftrace_branch_data \
1f0d69a9	118	__attribute__((__aligned__(4))) \
45b79749	119	__attribute__((section("_ftrace_annotated_branch"))) \
1f0d69a9 SR	120	______f = { \
	121	.func = __func__, \
	122	.file = __FILE__, \
	123	.line = __LINE__, \
	124	}; \
1f0d69a9	125	______r = likely_notrace(x); \
45b79749	126	ftrace_likely_update(&______f, ______r, expect); \
1f0d69a9 SR	127	______r; \
	128	})
	129
	130	/*
	131	* Using __builtin_constant_p(x) to ignore cases where the return
	132	* value is always the same. This idea is taken from a similar patch
	133	* written by Daniel Walker.
	134	*/
	135	# ifndef likely
45b79749	136	# define likely(x) (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 1))
1f0d69a9 SR	137	# endif
1f0d69a9 SR	138	# ifndef unlikely
45b79749	139	# define unlikely(x) (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 0))
1f0d69a9	140	# endif
2bcd521a SR	141
	142	#ifdef CONFIG_PROFILE_ALL_BRANCHES
	143	/*
	144	* "Define 'is'", Bill Clinton
	145	* "Define 'if'", Steven Rostedt
	146	*/
ab3c9c68 LT	147	#define if(cond, ...) __trace_if( (cond , ## __VA_ARGS__) )
ab3c9c68 LT	148	#define __trace_if(cond) \
b33c8ff4	149	if (__builtin_constant_p(!!(cond)) ? !!(cond) : \
2bcd521a SR	150	({ \
	151	int ______r; \
	152	static struct ftrace_branch_data \
	153	__attribute__((__aligned__(4))) \
	154	__attribute__((section("_ftrace_branch"))) \
	155	______f = { \
	156	.func = __func__, \
	157	.file = __FILE__, \
	158	.line = __LINE__, \
	159	}; \
	160	______r = !!(cond); \
97e7e4f3	161	______f.miss_hit[______r]++; \
2bcd521a SR	162	______r; \
	163	}))
	164	#endif /* CONFIG_PROFILE_ALL_BRANCHES */
	165
1f0d69a9 SR	166	#else
	167	# define likely(x) __builtin_expect(!!(x), 1)
	168	# define unlikely(x) __builtin_expect(!!(x), 0)
	169	#endif
1da177e4 LT	170
	171	/* Optimization barrier */
	172	#ifndef barrier
	173	# define barrier() __memory_barrier()
	174	#endif
	175
7829fb09 DB	176	#ifndef barrier_data
	177	# define barrier_data(ptr) barrier()
	178	#endif
	179
38938c87 DD	180	/* Unreachable code */
	181	#ifndef unreachable
	182	# define unreachable() do { } while (1)
	183	#endif
	184
1da177e4 LT	185	#ifndef RELOC_HIDE
	186	# define RELOC_HIDE(ptr, off) \
	187	({ unsigned long __ptr; \
	188	__ptr = (unsigned long) (ptr); \
	189	(typeof(ptr)) (__ptr + (off)); })
	190	#endif
	191
fe8c8a12 CEB	192	#ifndef OPTIMIZER_HIDE_VAR
	193	#define OPTIMIZER_HIDE_VAR(var) barrier()
	194	#endif
	195
6f33d587 RR	196	/* Not-quite-unique ID. */
	197	#ifndef __UNIQUE_ID
	198	# define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __LINE__)
	199	#endif
	200
230fa253 CB	201	#include <uapi/linux/types.h>
230fa253 CB	202
d976441f AR	203	#define __READ_ONCE_SIZE \
	204	({ \
	205	switch (size) { \
	206	case 1: (__u8 )res = (volatile __u8 )p; break; \
	207	case 2: (__u16 )res = (volatile __u16 )p; break; \
	208	case 4: (__u32 )res = (volatile __u32 )p; break; \
	209	case 8: (__u64 )res = (volatile __u64 )p; break; \
	210	default: \
	211	barrier(); \
	212	__builtin_memcpy((void )res, (const void )p, size); \
	213	barrier(); \
	214	} \
	215	})
	216
	217	static __always_inline
	218	void __read_once_size(const volatile void p, void res, int size)
230fa253	219	{
d976441f AR	220	__READ_ONCE_SIZE;
	221	}
	222
	223	#ifdef CONFIG_KASAN
	224	/*
	225	* This function is not 'inline' because __no_sanitize_address confilcts
	226	* with inlining. Attempt to inline it may cause a build failure.
	227	* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368
	228	* '__maybe_unused' allows us to avoid defined-but-not-used warnings.
	229	*/
	230	static __no_sanitize_address __maybe_unused
	231	void __read_once_size_nocheck(const volatile void p, void res, int size)
	232	{
	233	__READ_ONCE_SIZE;
	234	}
	235	#else
	236	static __always_inline
	237	void __read_once_size_nocheck(const volatile void p, void res, int size)
	238	{
	239	__READ_ONCE_SIZE;
230fa253	240	}
d976441f	241	#endif
230fa253	242
43239cbe	243	static __always_inline void __write_once_size(volatile void p, void res, int size)
230fa253 CB	244	{
	245	switch (size) {
	246	case 1: (volatile __u8 )p = (__u8 )res; break;
	247	case 2: (volatile __u16 )p = (__u16 )res; break;
	248	case 4: (volatile __u32 )p = (__u32 )res; break;
230fa253	249	case 8: (volatile __u64 )p = (__u64 )res; break;
230fa253 CB	250	default:
	251	barrier();
	252	__builtin_memcpy((void )p, (const void )res, size);
230fa253 CB	253	barrier();
	254	}
	255	}
	256
	257	/*
	258	* Prevent the compiler from merging or refetching reads or writes. The
	259	* compiler is also forbidden from reordering successive instances of
43239cbe	260	* READ_ONCE, WRITE_ONCE and ACCESS_ONCE (see below), but only when the
230fa253 CB	261	* compiler is aware of some particular ordering. One way to make the
230fa253 CB	262	* compiler aware of ordering is to put the two invocations of READ_ONCE,
43239cbe	263	* WRITE_ONCE or ACCESS_ONCE() in different C statements.
230fa253 CB	264	*
	265	* In contrast to ACCESS_ONCE these two macros will also work on aggregate
	266	* data types like structs or unions. If the size of the accessed data
	267	* type exceeds the word size of the machine (e.g., 32 bits or 64 bits)
fed0764f KRW	268	* READ_ONCE() and WRITE_ONCE() will fall back to memcpy(). There's at
	269	* least two memcpy()s: one for the __builtin_memcpy() and then one for
	270	* the macro doing the copy of variable - '__u' allocated on the stack.
230fa253 CB	271	*
	272	* Their two major use cases are: (1) Mediating communication between
	273	* process-level code and irq/NMI handlers, all running on the same CPU,
	274	* and (2) Ensuring that the compiler does not fold, spindle, or otherwise
	275	* mutilate accesses that either do not require ordering or that interact
	276	* with an explicit memory barrier or atomic instruction that provides the
	277	* required ordering.
	278	*/
	279
d976441f AR	280	#define __READ_ONCE(x, check) \
	281	({ \
	282	union { typeof(x) __val; char __c[1]; } __u; \
	283	if (check) \
	284	__read_once_size(&(x), __u.__c, sizeof(x)); \
	285	else \
	286	__read_once_size_nocheck(&(x), __u.__c, sizeof(x)); \
	287	__u.__val; \
	288	})
	289	#define READ_ONCE(x) __READ_ONCE(x, 1)
	290
	291	/*
	292	* Use READ_ONCE_NOCHECK() instead of READ_ONCE() if you need
	293	* to hide memory access from KASAN.
	294	*/
	295	#define READ_ONCE_NOCHECK(x) __READ_ONCE(x, 0)
230fa253	296
43239cbe	297	#define WRITE_ONCE(x, val) \
ba33034f CB	298	({ \
	299	union { typeof(x) __val; char __c[1]; } __u = \
	300	{ .__val = (__force typeof(x)) (val) }; \
	301	__write_once_size(&(x), __u.__c, sizeof(x)); \
	302	__u.__val; \
	303	})
230fa253	304
1da177e4 LT	305	#endif /* __KERNEL__ */
	306
	307	#endif /* __ASSEMBLY__ */
	308
4f79c3ff	309	#ifdef __KERNEL__
1da177e4 LT	310	/*
	311	* Allow us to mark functions as 'deprecated' and have gcc emit a nice
	312	* warning for each use, in hopes of speeding the functions removal.
	313	* Usage is:
	314	* int __deprecated foo(void)
	315	*/
	316	#ifndef __deprecated
	317	# define __deprecated /* unimplemented */
	318	#endif
	319
512345be PM	320	#ifdef MODULE
	321	#define __deprecated_for_modules __deprecated
	322	#else
	323	#define __deprecated_for_modules
	324	#endif
	325
1da177e4 LT	326	#ifndef __must_check
	327	#define __must_check
	328	#endif
	329
cebc04ba AM	330	#ifndef CONFIG_ENABLE_MUST_CHECK
	331	#undef __must_check
	332	#define __must_check
	333	#endif
de488443 JG	334	#ifndef CONFIG_ENABLE_WARN_DEPRECATED
	335	#undef __deprecated
	336	#undef __deprecated_for_modules
	337	#define __deprecated
	338	#define __deprecated_for_modules
	339	#endif
cebc04ba	340
d64e85d3 RV	341	#ifndef __malloc
	342	#define __malloc
	343	#endif
	344
1da177e4 LT	345	/*
	346	* Allow us to avoid 'defined but not used' warnings on functions and data,
	347	* as well as force them to be emitted to the assembly file.
	348	*
0d7ebbbc DR	349	* As of gcc 3.4, static functions that are not marked with attribute((used))
0d7ebbbc DR	350	* may be elided from the assembly file. As of gcc 3.4, static data not so
1da177e4 LT	351	* marked will not be elided, but this may change in a future gcc version.
1da177e4 LT	352	*
0d7ebbbc DR	353	* NOTE: Because distributions shipped with a backported unit-at-a-time
	354	* compiler in gcc 3.3, we must define __used to be __attribute__((used))
	355	* for gcc >=3.3 instead of 3.4.
	356	*
1da177e4 LT	357	* In prior versions of gcc, such functions and data would be emitted, but
1da177e4 LT	358	* would be warned about except with attribute((unused)).
0d7ebbbc DR	359	*
	360	* Mark functions that are referenced only in inline assembly as __used so
	361	* the code is emitted even though it appears to be unreferenced.
1da177e4	362	*/
0d7ebbbc DR	363	#ifndef __used
	364	# define __used /* unimplemented */
	365	#endif
	366
	367	#ifndef __maybe_unused
	368	# define __maybe_unused /* unimplemented */
1da177e4 LT	369	#endif
1da177e4 LT	370
7b2a3513 LZ	371	#ifndef __always_unused
	372	# define __always_unused /* unimplemented */
	373	#endif
	374
423bc7b2 DW	375	#ifndef noinline
	376	#define noinline
	377	#endif
	378
735c4fb9 AM	379	/*
735c4fb9 AM	380	* Rather then using noinline to prevent stack consumption, use
e6be0c9e	381	* noinline_for_stack instead. For documentation reasons.
735c4fb9 AM	382	*/
	383	#define noinline_for_stack noinline
	384
423bc7b2 DW	385	#ifndef __always_inline
	386	#define __always_inline inline
	387	#endif
	388
	389	#endif /* __KERNEL__ */
	390
1da177e4 LT	391	/*
	392	* From the GCC manual:
	393	*
	394	* Many functions do not examine any values except their arguments,
	395	* and have no effects except the return value. Basically this is
	396	* just slightly more strict class than the `pure' attribute above,
	397	* since function is not allowed to read global memory.
	398	*
	399	* Note that a function that has pointer arguments and examines the
	400	* data pointed to must _not_ be declared `const'. Likewise, a
	401	* function that calls a non-`const' function usually must not be
	402	* `const'. It does not make sense for a `const' function to return
	403	* `void'.
	404	*/
	405	#ifndef __attribute_const__
	406	# define __attribute_const__ /* unimplemented */
	407	#endif
	408
a586df06 AK	409	/*
	410	* Tell gcc if a function is cold. The compiler will assume any path
	411	* directly leading to the call is unlikely.
	412	*/
	413
	414	#ifndef __cold
	415	#define __cold
	416	#endif
	417
f3fe866d SR	418	/* Simple shorthand for a section definition */
	419	#ifndef __section
	420	# define __section(S) __attribute__ ((__section__(#S)))
	421	#endif
	422
9a858dc7 AK	423	#ifndef __visible
	424	#define __visible
	425	#endif
	426
a744fd17 RV	427	/*
	428	* Assume alignment of return value.
	429	*/
	430	#ifndef __assume_aligned
	431	#define __assume_aligned(a, ...)
	432	#endif
	433
	434
d2c123c2 RR	435	/* Are two types/vars the same type (ignoring qualifiers)? */
	436	#ifndef __same_type
	437	# define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
	438	#endif
	439
47933ad4 PZ	440	/* Is this type a native word size -- useful for atomic operations */
47933ad4 PZ	441	#ifndef __native_word
536fa402	442	# define __native_word(t) (sizeof(t) == sizeof(char) \|\| sizeof(t) == sizeof(short) \|\| sizeof(t) == sizeof(int) \|\| sizeof(t) == sizeof(long))
47933ad4 PZ	443	#endif
47933ad4 PZ	444
9f0cf4ad AV	445	/* Compile time object size, -1 for unknown */
	446	#ifndef __compiletime_object_size
	447	# define __compiletime_object_size(obj) -1
	448	#endif
4a312769 AV	449	#ifndef __compiletime_warning
	450	# define __compiletime_warning(message)
	451	#endif
63312b6a AV	452	#ifndef __compiletime_error
63312b6a AV	453	# define __compiletime_error(message)
2c0d259e JH	454	/*
	455	* Sparse complains of variable sized arrays due to the temporary variable in
	456	* __compiletime_assert. Unfortunately we can't just expand it out to make
	457	* sparse see a constant array size without breaking compiletime_assert on old
	458	* versions of GCC (e.g. 4.2.4), so hide the array from sparse altogether.
	459	*/
	460	# ifndef __CHECKER__
	461	# define __compiletime_error_fallback(condition) \
9a8ab1c3	462	do { ((void)sizeof(char[1 - 2 * condition])); } while (0)
2c0d259e JH	463	# endif
	464	#endif
	465	#ifndef __compiletime_error_fallback
c361d3e5	466	# define __compiletime_error_fallback(condition) do { } while (0)
63312b6a	467	#endif
c361d3e5	468
9a8ab1c3 DS	469	#define __compiletime_assert(condition, msg, prefix, suffix) \
	470	do { \
	471	bool __cond = !(condition); \
	472	extern void prefix ## suffix(void) __compiletime_error(msg); \
	473	if (__cond) \
	474	prefix ## suffix(); \
	475	__compiletime_error_fallback(__cond); \
	476	} while (0)
	477
	478	#define _compiletime_assert(condition, msg, prefix, suffix) \
	479	__compiletime_assert(condition, msg, prefix, suffix)
	480
	481	/**
	482	* compiletime_assert - break build and emit msg if condition is false
	483	* @condition: a compile-time constant condition to check
	484	* @msg: a message to emit if condition is false
	485	*
	486	* In tradition of POSIX assert, this macro will break the build if the
	487	* supplied condition is false, emitting the supplied error message if the
	488	* compiler has support to do so.
	489	*/
	490	#define compiletime_assert(condition, msg) \
	491	_compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
	492
47933ad4 PZ	493	#define compiletime_assert_atomic_type(t) \
	494	compiletime_assert(__native_word(t), \
	495	"Need native word sized stores/loads for atomicity.")
	496
9c3cdc1f LT	497	/*
	498	* Prevent the compiler from merging or refetching accesses. The compiler
	499	* is also forbidden from reordering successive instances of ACCESS_ONCE(),
	500	* but only when the compiler is aware of some particular ordering. One way
	501	* to make the compiler aware of ordering is to put the two invocations of
	502	* ACCESS_ONCE() in different C statements.
	503	*
927609d6 CB	504	* ACCESS_ONCE will only work on scalar types. For union types, ACCESS_ONCE
	505	* on a union member will work as long as the size of the member matches the
	506	* size of the union and the size is smaller than word size.
	507	*
	508	* The major use cases of ACCESS_ONCE used to be (1) Mediating communication
	509	* between process-level code and irq/NMI handlers, all running on the same CPU,
	510	* and (2) Ensuring that the compiler does not fold, spindle, or otherwise
	511	* mutilate accesses that either do not require ordering or that interact
	512	* with an explicit memory barrier or atomic instruction that provides the
	513	* required ordering.
	514	*
663fdcbe	515	* If possible use READ_ONCE()/WRITE_ONCE() instead.
9c3cdc1f	516	*/
927609d6	517	#define __ACCESS_ONCE(x) ({ \
c5b19946	518	__maybe_unused typeof(x) __var = (__force typeof(x)) 0; \
927609d6 CB	519	(volatile typeof(x) *)&(x); })
927609d6 CB	520	#define ACCESS_ONCE(x) (*__ACCESS_ONCE(x))
9c3cdc1f	521
0a04b016 PZ	522	/**
	523	* lockless_dereference() - safely load a pointer for later dereference
	524	* @p: The pointer to load
	525	*
	526	* Similar to rcu_dereference(), but for situations where the pointed-to
	527	* object's lifetime is managed by something other than RCU. That
	528	* "something other" might be reference counting or simple immortality.
331b6d8c	529	*
d7127b5e JB	530	* The seemingly unused variable ___typecheck_p validates that @p is
	531	* indeed a pointer type by using a pointer to typeof(*p) as the type.
	532	* Taking a pointer to typeof(p) again is needed in case p is void .
0a04b016 PZ	533	*/
	534	#define lockless_dereference(p) \
	535	({ \
38183b9c	536	typeof(p) _________p1 = READ_ONCE(p); \
d7127b5e	537	typeof((p)) ___typecheck_p __maybe_unused; \
0a04b016 PZ	538	smp_read_barrier_depends(); /* Dependency order vs. p above. */ \
	539	(_________p1); \
	540	})
	541
324670b6 MH	542	/* Ignore/forbid kprobes attach on very low level functions marked by this attribute: */
	543	#ifdef CONFIG_KPROBES
	544	# define __kprobes __attribute__((__section__(".kprobes.text")))
376e2424	545	# define nokprobe_inline __always_inline
324670b6 MH	546	#else
324670b6 MH	547	# define __kprobes
376e2424	548	# define nokprobe_inline inline
324670b6	549	#endif
1da177e4	550	#endif /* __LINUX_COMPILER_H */