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 struct ftrace_branch_data {
66 unsigned long correct;
67 unsigned long incorrect;
71 * Note: DISABLE_BRANCH_PROFILING can be used by special lowlevel code
72 * to disable branch tracing on a per file basis.
74 #if defined(CONFIG_TRACE_BRANCH_PROFILING) && !defined(DISABLE_BRANCH_PROFILING)
75 void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
77 #define likely_notrace(x) __builtin_expect(!!(x), 1)
78 #define unlikely_notrace(x) __builtin_expect(!!(x), 0)
80 #define likely_check(x) ({ \
82 static struct ftrace_branch_data \
83 __attribute__((__aligned__(4))) \
84 __attribute__((section("_ftrace_likely"))) \
90 ______r = likely_notrace(x); \
91 ftrace_likely_update(&______f, ______r, 1); \
94 #define unlikely_check(x) ({ \
96 static struct ftrace_branch_data \
97 __attribute__((__aligned__(4))) \
98 __attribute__((section("_ftrace_unlikely"))) \
104 ______r = unlikely_notrace(x); \
105 ftrace_likely_update(&______f, ______r, 0); \
110 * Using __builtin_constant_p(x) to ignore cases where the return
111 * value is always the same. This idea is taken from a similar patch
112 * written by Daniel Walker.
115 # define likely(x) (__builtin_constant_p(x) ? !!(x) : likely_check(x))
118 # define unlikely(x) (__builtin_constant_p(x) ? !!(x) : unlikely_check(x))
121 # define likely(x) __builtin_expect(!!(x), 1)
122 # define unlikely(x) __builtin_expect(!!(x), 0)
125 /* Optimization barrier */
127 # define barrier() __memory_barrier()
131 # define RELOC_HIDE(ptr, off) \
132 ({ unsigned long __ptr; \
133 __ptr = (unsigned long) (ptr); \
134 (typeof(ptr)) (__ptr + (off)); })
137 #endif /* __KERNEL__ */
139 #endif /* __ASSEMBLY__ */
143 * Allow us to mark functions as 'deprecated' and have gcc emit a nice
144 * warning for each use, in hopes of speeding the functions removal.
146 * int __deprecated foo(void)
149 # define __deprecated /* unimplemented */
153 #define __deprecated_for_modules __deprecated
155 #define __deprecated_for_modules
162 #ifndef CONFIG_ENABLE_MUST_CHECK
166 #ifndef CONFIG_ENABLE_WARN_DEPRECATED
168 #undef __deprecated_for_modules
170 #define __deprecated_for_modules
174 * Allow us to avoid 'defined but not used' warnings on functions and data,
175 * as well as force them to be emitted to the assembly file.
177 * As of gcc 3.4, static functions that are not marked with attribute((used))
178 * may be elided from the assembly file. As of gcc 3.4, static data not so
179 * marked will not be elided, but this may change in a future gcc version.
181 * NOTE: Because distributions shipped with a backported unit-at-a-time
182 * compiler in gcc 3.3, we must define __used to be __attribute__((used))
183 * for gcc >=3.3 instead of 3.4.
185 * In prior versions of gcc, such functions and data would be emitted, but
186 * would be warned about except with attribute((unused)).
188 * Mark functions that are referenced only in inline assembly as __used so
189 * the code is emitted even though it appears to be unreferenced.
192 # define __used /* unimplemented */
195 #ifndef __maybe_unused
196 # define __maybe_unused /* unimplemented */
204 * Rather then using noinline to prevent stack consumption, use
205 * noinline_for_stack instead. For documentaiton reasons.
207 #define noinline_for_stack noinline
209 #ifndef __always_inline
210 #define __always_inline inline
213 #endif /* __KERNEL__ */
216 * From the GCC manual:
218 * Many functions do not examine any values except their arguments,
219 * and have no effects except the return value. Basically this is
220 * just slightly more strict class than the `pure' attribute above,
221 * since function is not allowed to read global memory.
223 * Note that a function that has pointer arguments and examines the
224 * data pointed to must _not_ be declared `const'. Likewise, a
225 * function that calls a non-`const' function usually must not be
226 * `const'. It does not make sense for a `const' function to return
229 #ifndef __attribute_const__
230 # define __attribute_const__ /* unimplemented */
234 * Tell gcc if a function is cold. The compiler will assume any path
235 * directly leading to the call is unlikely.
242 /* Simple shorthand for a section definition */
244 # define __section(S) __attribute__ ((__section__(#S)))
248 * Prevent the compiler from merging or refetching accesses. The compiler
249 * is also forbidden from reordering successive instances of ACCESS_ONCE(),
250 * but only when the compiler is aware of some particular ordering. One way
251 * to make the compiler aware of ordering is to put the two invocations of
252 * ACCESS_ONCE() in different C statements.
254 * This macro does absolutely -nothing- to prevent the CPU from reordering,
255 * merging, or refetching absolutely anything at any time. Its main intended
256 * use is to mediate communication between process-level code and irq/NMI
257 * handlers, all running on the same CPU.
259 #define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
261 #endif /* __LINUX_COMPILER_H */