1 #ifndef __LINUX_COMPILER_H
2 #define __LINUX_COMPILER_H
7 # define __user __attribute__((noderef, address_space(1)))
8 # define __kernel /* default address space */
9 # define __safe __attribute__((safe))
10 # define __force __attribute__((force))
11 # define __nocast __attribute__((nocast))
12 # define __iomem __attribute__((noderef, address_space(2)))
13 # define __acquires(x) __attribute__((context(x,0,1)))
14 # define __releases(x) __attribute__((context(x,1,0)))
15 # define __acquire(x) __context__(x,1)
16 # define __release(x) __context__(x,-1)
17 # define __cond_lock(x,c) ((c) ? ({ __acquire(x); 1; }) : 0)
18 extern void __chk_user_ptr(const volatile void __user *);
19 extern void __chk_io_ptr(const volatile void __iomem *);
27 # define __chk_user_ptr(x) (void)0
28 # define __chk_io_ptr(x) (void)0
29 # define __builtin_warning(x, y...) (1)
30 # define __acquires(x)
31 # define __releases(x)
32 # define __acquire(x) (void)0
33 # define __release(x) (void)0
34 # define __cond_lock(x,c) (c)
40 # include <linux/compiler-gcc4.h>
41 #elif __GNUC__ == 3 && __GNUC_MINOR__ >= 2
42 # include <linux/compiler-gcc3.h>
44 # error Sorry, your compiler is too old/not recognized.
47 #define notrace __attribute__((no_instrument_function))
49 /* Intel compiler defines __GNUC__. So we will overwrite implementations
50 * coming from above header files here
52 #ifdef __INTEL_COMPILER
53 # include <linux/compiler-intel.h>
57 * Generic compiler-dependent macros required for kernel
58 * build go below this comment. Actual compiler/compiler version
59 * specific implementations come from the above header files
62 #ifdef CONFIG_TRACE_UNLIKELY_PROFILE
63 struct ftrace_likely_data {
67 unsigned long correct;
68 unsigned long incorrect;
70 void ftrace_likely_update(struct ftrace_likely_data *f, int val, int expect);
72 #define likely_notrace(x) __builtin_expect(!!(x), 1)
73 #define unlikely_notrace(x) __builtin_expect(!!(x), 0)
75 #define likely_check(x) ({ \
77 static struct ftrace_likely_data \
78 __attribute__((__aligned__(4))) \
79 __attribute__((section("_ftrace_likely"))) \
85 ______f.line = __LINE__; \
86 ______r = likely_notrace(x); \
87 ftrace_likely_update(&______f, ______r, 1); \
90 #define unlikely_check(x) ({ \
92 static struct ftrace_likely_data \
93 __attribute__((__aligned__(4))) \
94 __attribute__((section("_ftrace_unlikely"))) \
100 ______f.line = __LINE__; \
101 ______r = unlikely_notrace(x); \
102 ftrace_likely_update(&______f, ______r, 0); \
107 * Using __builtin_constant_p(x) to ignore cases where the return
108 * value is always the same. This idea is taken from a similar patch
109 * written by Daniel Walker.
112 # define likely(x) (__builtin_constant_p(x) ? !!(x) : likely_check(x))
115 # define unlikely(x) (__builtin_constant_p(x) ? !!(x) : unlikely_check(x))
118 # define likely(x) __builtin_expect(!!(x), 1)
119 # define unlikely(x) __builtin_expect(!!(x), 0)
122 /* Optimization barrier */
124 # define barrier() __memory_barrier()
128 # define RELOC_HIDE(ptr, off) \
129 ({ unsigned long __ptr; \
130 __ptr = (unsigned long) (ptr); \
131 (typeof(ptr)) (__ptr + (off)); })
134 #endif /* __KERNEL__ */
136 #endif /* __ASSEMBLY__ */
140 * Allow us to mark functions as 'deprecated' and have gcc emit a nice
141 * warning for each use, in hopes of speeding the functions removal.
143 * int __deprecated foo(void)
146 # define __deprecated /* unimplemented */
150 #define __deprecated_for_modules __deprecated
152 #define __deprecated_for_modules
159 #ifndef CONFIG_ENABLE_MUST_CHECK
163 #ifndef CONFIG_ENABLE_WARN_DEPRECATED
165 #undef __deprecated_for_modules
167 #define __deprecated_for_modules
171 * Allow us to avoid 'defined but not used' warnings on functions and data,
172 * as well as force them to be emitted to the assembly file.
174 * As of gcc 3.4, static functions that are not marked with attribute((used))
175 * may be elided from the assembly file. As of gcc 3.4, static data not so
176 * marked will not be elided, but this may change in a future gcc version.
178 * NOTE: Because distributions shipped with a backported unit-at-a-time
179 * compiler in gcc 3.3, we must define __used to be __attribute__((used))
180 * for gcc >=3.3 instead of 3.4.
182 * In prior versions of gcc, such functions and data would be emitted, but
183 * would be warned about except with attribute((unused)).
185 * Mark functions that are referenced only in inline assembly as __used so
186 * the code is emitted even though it appears to be unreferenced.
189 # define __used /* unimplemented */
192 #ifndef __maybe_unused
193 # define __maybe_unused /* unimplemented */
201 * Rather then using noinline to prevent stack consumption, use
202 * noinline_for_stack instead. For documentaiton reasons.
204 #define noinline_for_stack noinline
206 #ifndef __always_inline
207 #define __always_inline inline
210 #endif /* __KERNEL__ */
213 * From the GCC manual:
215 * Many functions do not examine any values except their arguments,
216 * and have no effects except the return value. Basically this is
217 * just slightly more strict class than the `pure' attribute above,
218 * since function is not allowed to read global memory.
220 * Note that a function that has pointer arguments and examines the
221 * data pointed to must _not_ be declared `const'. Likewise, a
222 * function that calls a non-`const' function usually must not be
223 * `const'. It does not make sense for a `const' function to return
226 #ifndef __attribute_const__
227 # define __attribute_const__ /* unimplemented */
231 * Tell gcc if a function is cold. The compiler will assume any path
232 * directly leading to the call is unlikely.
239 /* Simple shorthand for a section definition */
241 # define __section(S) __attribute__ ((__section__(#S)))
245 * Prevent the compiler from merging or refetching accesses. The compiler
246 * is also forbidden from reordering successive instances of ACCESS_ONCE(),
247 * but only when the compiler is aware of some particular ordering. One way
248 * to make the compiler aware of ordering is to put the two invocations of
249 * ACCESS_ONCE() in different C statements.
251 * This macro does absolutely -nothing- to prevent the CPU from reordering,
252 * merging, or refetching absolutely anything at any time. Its main intended
253 * use is to mediate communication between process-level code and irq/NMI
254 * handlers, all running on the same CPU.
256 #define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
258 #endif /* __LINUX_COMPILER_H */