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
63 * Note: DISABLE_UNLIKELY_PROFILE can be used by special lowlevel code
64 * to disable branch tracing on a per file basis.
66 #if defined(CONFIG_TRACE_UNLIKELY_PROFILE) && !defined(DISABLE_UNLIKELY_PROFILE)
67 struct ftrace_likely_data {
71 unsigned long correct;
72 unsigned long incorrect;
74 void ftrace_likely_update(struct ftrace_likely_data *f, int val, int expect);
76 #define likely_notrace(x) __builtin_expect(!!(x), 1)
77 #define unlikely_notrace(x) __builtin_expect(!!(x), 0)
79 #define likely_check(x) ({ \
81 static struct ftrace_likely_data \
82 __attribute__((__aligned__(4))) \
83 __attribute__((section("_ftrace_likely"))) \
89 ______f.line = __LINE__; \
90 ______r = likely_notrace(x); \
91 ftrace_likely_update(&______f, ______r, 1); \
94 #define unlikely_check(x) ({ \
96 static struct ftrace_likely_data \
97 __attribute__((__aligned__(4))) \
98 __attribute__((section("_ftrace_unlikely"))) \
104 ______f.line = __LINE__; \
105 ______r = unlikely_notrace(x); \
106 ftrace_likely_update(&______f, ______r, 0); \
111 * Using __builtin_constant_p(x) to ignore cases where the return
112 * value is always the same. This idea is taken from a similar patch
113 * written by Daniel Walker.
116 # define likely(x) (__builtin_constant_p(x) ? !!(x) : likely_check(x))
119 # define unlikely(x) (__builtin_constant_p(x) ? !!(x) : unlikely_check(x))
122 # define likely(x) __builtin_expect(!!(x), 1)
123 # define unlikely(x) __builtin_expect(!!(x), 0)
126 /* Optimization barrier */
128 # define barrier() __memory_barrier()
132 # define RELOC_HIDE(ptr, off) \
133 ({ unsigned long __ptr; \
134 __ptr = (unsigned long) (ptr); \
135 (typeof(ptr)) (__ptr + (off)); })
138 #endif /* __KERNEL__ */
140 #endif /* __ASSEMBLY__ */
144 * Allow us to mark functions as 'deprecated' and have gcc emit a nice
145 * warning for each use, in hopes of speeding the functions removal.
147 * int __deprecated foo(void)
150 # define __deprecated /* unimplemented */
154 #define __deprecated_for_modules __deprecated
156 #define __deprecated_for_modules
163 #ifndef CONFIG_ENABLE_MUST_CHECK
167 #ifndef CONFIG_ENABLE_WARN_DEPRECATED
169 #undef __deprecated_for_modules
171 #define __deprecated_for_modules
175 * Allow us to avoid 'defined but not used' warnings on functions and data,
176 * as well as force them to be emitted to the assembly file.
178 * As of gcc 3.4, static functions that are not marked with attribute((used))
179 * may be elided from the assembly file. As of gcc 3.4, static data not so
180 * marked will not be elided, but this may change in a future gcc version.
182 * NOTE: Because distributions shipped with a backported unit-at-a-time
183 * compiler in gcc 3.3, we must define __used to be __attribute__((used))
184 * for gcc >=3.3 instead of 3.4.
186 * In prior versions of gcc, such functions and data would be emitted, but
187 * would be warned about except with attribute((unused)).
189 * Mark functions that are referenced only in inline assembly as __used so
190 * the code is emitted even though it appears to be unreferenced.
193 # define __used /* unimplemented */
196 #ifndef __maybe_unused
197 # define __maybe_unused /* unimplemented */
205 * Rather then using noinline to prevent stack consumption, use
206 * noinline_for_stack instead. For documentaiton reasons.
208 #define noinline_for_stack noinline
210 #ifndef __always_inline
211 #define __always_inline inline
214 #endif /* __KERNEL__ */
217 * From the GCC manual:
219 * Many functions do not examine any values except their arguments,
220 * and have no effects except the return value. Basically this is
221 * just slightly more strict class than the `pure' attribute above,
222 * since function is not allowed to read global memory.
224 * Note that a function that has pointer arguments and examines the
225 * data pointed to must _not_ be declared `const'. Likewise, a
226 * function that calls a non-`const' function usually must not be
227 * `const'. It does not make sense for a `const' function to return
230 #ifndef __attribute_const__
231 # define __attribute_const__ /* unimplemented */
235 * Tell gcc if a function is cold. The compiler will assume any path
236 * directly leading to the call is unlikely.
243 /* Simple shorthand for a section definition */
245 # define __section(S) __attribute__ ((__section__(#S)))
249 * Prevent the compiler from merging or refetching accesses. The compiler
250 * is also forbidden from reordering successive instances of ACCESS_ONCE(),
251 * but only when the compiler is aware of some particular ordering. One way
252 * to make the compiler aware of ordering is to put the two invocations of
253 * ACCESS_ONCE() in different C statements.
255 * This macro does absolutely -nothing- to prevent the CPU from reordering,
256 * merging, or refetching absolutely anything at any time. Its main intended
257 * use is to mediate communication between process-level code and irq/NMI
258 * handlers, all running on the same CPU.
260 #define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
262 #endif /* __LINUX_COMPILER_H */