compiler.h 8.8 KB

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  1. #ifndef __LINUX_COMPILER_H
  2. #define __LINUX_COMPILER_H
  3. #ifndef __ASSEMBLY__
  4. #ifdef __CHECKER__
  5. # define __user __attribute__((noderef, address_space(1)))
  6. # define __kernel __attribute__((address_space(0)))
  7. # define __safe __attribute__((safe))
  8. # define __force __attribute__((force))
  9. # define __nocast __attribute__((nocast))
  10. # define __iomem __attribute__((noderef, address_space(2)))
  11. # define __acquires(x) __attribute__((context(x,0,1)))
  12. # define __releases(x) __attribute__((context(x,1,0)))
  13. # define __acquire(x) __context__(x,1)
  14. # define __release(x) __context__(x,-1)
  15. # define __cond_lock(x,c) ((c) ? ({ __acquire(x); 1; }) : 0)
  16. # define __percpu __attribute__((noderef, address_space(3)))
  17. #ifdef CONFIG_SPARSE_RCU_POINTER
  18. # define __rcu __attribute__((noderef, address_space(4)))
  19. #else
  20. # define __rcu
  21. #endif
  22. extern void __chk_user_ptr(const volatile void __user *);
  23. extern void __chk_io_ptr(const volatile void __iomem *);
  24. #else
  25. # define __user
  26. # define __kernel
  27. # define __safe
  28. # define __force
  29. # define __nocast
  30. # define __iomem
  31. # define __chk_user_ptr(x) (void)0
  32. # define __chk_io_ptr(x) (void)0
  33. # define __builtin_warning(x, y...) (1)
  34. # define __acquires(x)
  35. # define __releases(x)
  36. # define __acquire(x) (void)0
  37. # define __release(x) (void)0
  38. # define __cond_lock(x,c) (c)
  39. # define __percpu
  40. # define __rcu
  41. #endif
  42. /* Indirect macros required for expanded argument pasting, eg. __LINE__. */
  43. #define ___PASTE(a,b) a##b
  44. #define __PASTE(a,b) ___PASTE(a,b)
  45. #ifdef __KERNEL__
  46. #ifdef __GNUC__
  47. #include <linux/compiler-gcc.h>
  48. #endif
  49. #define notrace __attribute__((no_instrument_function))
  50. /* Intel compiler defines __GNUC__. So we will overwrite implementations
  51. * coming from above header files here
  52. */
  53. #ifdef __INTEL_COMPILER
  54. # include <linux/compiler-intel.h>
  55. #endif
  56. /*
  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
  60. */
  61. struct ftrace_branch_data {
  62. const char *func;
  63. const char *file;
  64. unsigned line;
  65. union {
  66. struct {
  67. unsigned long correct;
  68. unsigned long incorrect;
  69. };
  70. struct {
  71. unsigned long miss;
  72. unsigned long hit;
  73. };
  74. unsigned long miss_hit[2];
  75. };
  76. };
  77. /*
  78. * Note: DISABLE_BRANCH_PROFILING can be used by special lowlevel code
  79. * to disable branch tracing on a per file basis.
  80. */
  81. #if defined(CONFIG_TRACE_BRANCH_PROFILING) \
  82. && !defined(DISABLE_BRANCH_PROFILING) && !defined(__CHECKER__)
  83. void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
  84. #define likely_notrace(x) __builtin_expect(!!(x), 1)
  85. #define unlikely_notrace(x) __builtin_expect(!!(x), 0)
  86. #define __branch_check__(x, expect) ({ \
  87. int ______r; \
  88. static struct ftrace_branch_data \
  89. __attribute__((__aligned__(4))) \
  90. __attribute__((section("_ftrace_annotated_branch"))) \
  91. ______f = { \
  92. .func = __func__, \
  93. .file = __FILE__, \
  94. .line = __LINE__, \
  95. }; \
  96. ______r = likely_notrace(x); \
  97. ftrace_likely_update(&______f, ______r, expect); \
  98. ______r; \
  99. })
  100. /*
  101. * Using __builtin_constant_p(x) to ignore cases where the return
  102. * value is always the same. This idea is taken from a similar patch
  103. * written by Daniel Walker.
  104. */
  105. # ifndef likely
  106. # define likely(x) (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 1))
  107. # endif
  108. # ifndef unlikely
  109. # define unlikely(x) (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 0))
  110. # endif
  111. #ifdef CONFIG_PROFILE_ALL_BRANCHES
  112. /*
  113. * "Define 'is'", Bill Clinton
  114. * "Define 'if'", Steven Rostedt
  115. */
  116. #define if(cond, ...) __trace_if( (cond , ## __VA_ARGS__) )
  117. #define __trace_if(cond) \
  118. if (__builtin_constant_p((cond)) ? !!(cond) : \
  119. ({ \
  120. int ______r; \
  121. static struct ftrace_branch_data \
  122. __attribute__((__aligned__(4))) \
  123. __attribute__((section("_ftrace_branch"))) \
  124. ______f = { \
  125. .func = __func__, \
  126. .file = __FILE__, \
  127. .line = __LINE__, \
  128. }; \
  129. ______r = !!(cond); \
  130. ______f.miss_hit[______r]++; \
  131. ______r; \
  132. }))
  133. #endif /* CONFIG_PROFILE_ALL_BRANCHES */
  134. #else
  135. # define likely(x) __builtin_expect(!!(x), 1)
  136. # define unlikely(x) __builtin_expect(!!(x), 0)
  137. #endif
  138. /* Optimization barrier */
  139. #ifndef barrier
  140. # define barrier() __memory_barrier()
  141. #endif
  142. /* Unreachable code */
  143. #ifndef unreachable
  144. # define unreachable() do { } while (1)
  145. #endif
  146. #ifndef RELOC_HIDE
  147. # define RELOC_HIDE(ptr, off) \
  148. ({ unsigned long __ptr; \
  149. __ptr = (unsigned long) (ptr); \
  150. (typeof(ptr)) (__ptr + (off)); })
  151. #endif
  152. /* Not-quite-unique ID. */
  153. #ifndef __UNIQUE_ID
  154. # define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __LINE__)
  155. #endif
  156. #endif /* __KERNEL__ */
  157. #endif /* __ASSEMBLY__ */
  158. #ifdef __KERNEL__
  159. /*
  160. * Allow us to mark functions as 'deprecated' and have gcc emit a nice
  161. * warning for each use, in hopes of speeding the functions removal.
  162. * Usage is:
  163. * int __deprecated foo(void)
  164. */
  165. #ifndef __deprecated
  166. # define __deprecated /* unimplemented */
  167. #endif
  168. #ifdef MODULE
  169. #define __deprecated_for_modules __deprecated
  170. #else
  171. #define __deprecated_for_modules
  172. #endif
  173. #ifndef __must_check
  174. #define __must_check
  175. #endif
  176. #ifndef CONFIG_ENABLE_MUST_CHECK
  177. #undef __must_check
  178. #define __must_check
  179. #endif
  180. #ifndef CONFIG_ENABLE_WARN_DEPRECATED
  181. #undef __deprecated
  182. #undef __deprecated_for_modules
  183. #define __deprecated
  184. #define __deprecated_for_modules
  185. #endif
  186. /*
  187. * Allow us to avoid 'defined but not used' warnings on functions and data,
  188. * as well as force them to be emitted to the assembly file.
  189. *
  190. * As of gcc 3.4, static functions that are not marked with attribute((used))
  191. * may be elided from the assembly file. As of gcc 3.4, static data not so
  192. * marked will not be elided, but this may change in a future gcc version.
  193. *
  194. * NOTE: Because distributions shipped with a backported unit-at-a-time
  195. * compiler in gcc 3.3, we must define __used to be __attribute__((used))
  196. * for gcc >=3.3 instead of 3.4.
  197. *
  198. * In prior versions of gcc, such functions and data would be emitted, but
  199. * would be warned about except with attribute((unused)).
  200. *
  201. * Mark functions that are referenced only in inline assembly as __used so
  202. * the code is emitted even though it appears to be unreferenced.
  203. */
  204. #ifndef __used
  205. # define __used /* unimplemented */
  206. #endif
  207. #ifndef __maybe_unused
  208. # define __maybe_unused /* unimplemented */
  209. #endif
  210. #ifndef __always_unused
  211. # define __always_unused /* unimplemented */
  212. #endif
  213. #ifndef noinline
  214. #define noinline
  215. #endif
  216. /*
  217. * Rather then using noinline to prevent stack consumption, use
  218. * noinline_for_stack instead. For documentation reasons.
  219. */
  220. #define noinline_for_stack noinline
  221. #ifndef __always_inline
  222. #define __always_inline inline
  223. #endif
  224. #endif /* __KERNEL__ */
  225. /*
  226. * From the GCC manual:
  227. *
  228. * Many functions do not examine any values except their arguments,
  229. * and have no effects except the return value. Basically this is
  230. * just slightly more strict class than the `pure' attribute above,
  231. * since function is not allowed to read global memory.
  232. *
  233. * Note that a function that has pointer arguments and examines the
  234. * data pointed to must _not_ be declared `const'. Likewise, a
  235. * function that calls a non-`const' function usually must not be
  236. * `const'. It does not make sense for a `const' function to return
  237. * `void'.
  238. */
  239. #ifndef __attribute_const__
  240. # define __attribute_const__ /* unimplemented */
  241. #endif
  242. /*
  243. * Tell gcc if a function is cold. The compiler will assume any path
  244. * directly leading to the call is unlikely.
  245. */
  246. #ifndef __cold
  247. #define __cold
  248. #endif
  249. /* Simple shorthand for a section definition */
  250. #ifndef __section
  251. # define __section(S) __attribute__ ((__section__(#S)))
  252. #endif
  253. #ifndef __visible
  254. #define __visible
  255. #endif
  256. /* Are two types/vars the same type (ignoring qualifiers)? */
  257. #ifndef __same_type
  258. # define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
  259. #endif
  260. /* Compile time object size, -1 for unknown */
  261. #ifndef __compiletime_object_size
  262. # define __compiletime_object_size(obj) -1
  263. #endif
  264. #ifndef __compiletime_warning
  265. # define __compiletime_warning(message)
  266. #endif
  267. #ifndef __compiletime_error
  268. # define __compiletime_error(message)
  269. #endif
  270. #ifndef __linktime_error
  271. # define __linktime_error(message)
  272. #endif
  273. /*
  274. * Prevent the compiler from merging or refetching accesses. The compiler
  275. * is also forbidden from reordering successive instances of ACCESS_ONCE(),
  276. * but only when the compiler is aware of some particular ordering. One way
  277. * to make the compiler aware of ordering is to put the two invocations of
  278. * ACCESS_ONCE() in different C statements.
  279. *
  280. * This macro does absolutely -nothing- to prevent the CPU from reordering,
  281. * merging, or refetching absolutely anything at any time. Its main intended
  282. * use is to mediate communication between process-level code and irq/NMI
  283. * handlers, all running on the same CPU.
  284. */
  285. #define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
  286. #endif /* __LINUX_COMPILER_H */