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))) 8 # define __kernel __attribute__((address_space(0))) 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 __must_hold(x) __attribute__((context(x,1,1))) 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) 18 # define __cond_lock(x,c) ((c) ? ({ __acquire(x); 1; }) : 0) 19 # define __percpu __attribute__((noderef, address_space(3))) 20 #ifdef CONFIG_SPARSE_RCU_POINTER 21 # define __rcu __attribute__((noderef, address_space(4))) 22 #else 23 # define __rcu 24 #endif 25 extern void __chk_user_ptr(const volatile void __user *); 26 extern void __chk_io_ptr(const volatile void __iomem *); 27 #else 28 # define __user 29 # define __kernel 30 # define __safe 31 # define __force 32 # define __nocast 33 # define __iomem 34 # define __chk_user_ptr(x) (void)0 35 # define __chk_io_ptr(x) (void)0 36 # define __builtin_warning(x, y...) (1) 37 # define __must_hold(x) 38 # define __acquires(x) 39 # define __releases(x) 40 # define __acquire(x) (void)0 41 # define __release(x) (void)0 42 # define __cond_lock(x,c) (c) 43 # define __percpu 44 # define __rcu 45 #endif 46 47 /* Indirect macros required for expanded argument pasting, eg. __LINE__. */ 48 #define ___PASTE(a,b) a##b 49 #define __PASTE(a,b) ___PASTE(a,b) 50 51 #ifdef __KERNEL__ 52 53 #ifdef __GNUC__ 54 #include <linux/compiler-gcc.h> 55 #endif 56 57 #define notrace __attribute__((no_instrument_function)) 58 59 /* Intel compiler defines __GNUC__. So we will overwrite implementations 60 * coming from above header files here 61 */ 62 #ifdef __INTEL_COMPILER 63 # include <linux/compiler-intel.h> 64 #endif 65 66 /* Clang compiler defines __GNUC__. So we will overwrite implementations 67 * coming from above header files here 68 */ 69 #ifdef __clang__ 70 #include <linux/compiler-clang.h> 71 #endif 72 73 /* 74 * Generic compiler-dependent macros required for kernel 75 * build go below this comment. Actual compiler/compiler version 76 * specific implementations come from the above header files 77 */ 78 79 struct ftrace_branch_data { 80 const char *func; 81 const char *file; 82 unsigned line; 83 union { 84 struct { 85 unsigned long correct; 86 unsigned long incorrect; 87 }; 88 struct { 89 unsigned long miss; 90 unsigned long hit; 91 }; 92 unsigned long miss_hit[2]; 93 }; 94 }; 95 96 /* 97 * Note: DISABLE_BRANCH_PROFILING can be used by special lowlevel code 98 * to disable branch tracing on a per file basis. 99 */ 100 #if defined(CONFIG_TRACE_BRANCH_PROFILING) \ 101 && !defined(DISABLE_BRANCH_PROFILING) && !defined(__CHECKER__) 102 void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect); 103 104 #define likely_notrace(x) __builtin_expect(!!(x), 1) 105 #define unlikely_notrace(x) __builtin_expect(!!(x), 0) 106 107 #define __branch_check__(x, expect) ({ \ 108 int ______r; \ 109 static struct ftrace_branch_data \ 110 __attribute__((__aligned__(4))) \ 111 __attribute__((section("_ftrace_annotated_branch"))) \ 112 ______f = { \ 113 .func = __func__, \ 114 .file = __FILE__, \ 115 .line = __LINE__, \ 116 }; \ 117 ______r = likely_notrace(x); \ 118 ftrace_likely_update(&______f, ______r, expect); \ 119 ______r; \ 120 }) 121 122 /* 123 * Using __builtin_constant_p(x) to ignore cases where the return 124 * value is always the same. This idea is taken from a similar patch 125 * written by Daniel Walker. 126 */ 127 # ifndef likely 128 # define likely(x) (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 1)) 129 # endif 130 # ifndef unlikely 131 # define unlikely(x) (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 0)) 132 # endif 133 134 #ifdef CONFIG_PROFILE_ALL_BRANCHES 135 /* 136 * "Define 'is'", Bill Clinton 137 * "Define 'if'", Steven Rostedt 138 */ 139 #define if(cond, ...) __trace_if( (cond , ## __VA_ARGS__) ) 140 #define __trace_if(cond) \ 141 if (__builtin_constant_p((cond)) ? !!(cond) : \ 142 ({ \ 143 int ______r; \ 144 static struct ftrace_branch_data \ 145 __attribute__((__aligned__(4))) \ 146 __attribute__((section("_ftrace_branch"))) \ 147 ______f = { \ 148 .func = __func__, \ 149 .file = __FILE__, \ 150 .line = __LINE__, \ 151 }; \ 152 ______r = !!(cond); \ 153 ______f.miss_hit[______r]++; \ 154 ______r; \ 155 })) 156 #endif /* CONFIG_PROFILE_ALL_BRANCHES */ 157 158 #else 159 # define likely(x) __builtin_expect(!!(x), 1) 160 # define unlikely(x) __builtin_expect(!!(x), 0) 161 #endif 162 163 /* Optimization barrier */ 164 #ifndef barrier 165 # define barrier() __memory_barrier() 166 #endif 167 168 /* Unreachable code */ 169 #ifndef unreachable 170 # define unreachable() do { } while (1) 171 #endif 172 173 #ifndef RELOC_HIDE 174 # define RELOC_HIDE(ptr, off) \ 175 ({ unsigned long __ptr; \ 176 __ptr = (unsigned long) (ptr); \ 177 (typeof(ptr)) (__ptr + (off)); }) 178 #endif 179 180 #ifndef OPTIMIZER_HIDE_VAR 181 #define OPTIMIZER_HIDE_VAR(var) barrier() 182 #endif 183 184 /* Not-quite-unique ID. */ 185 #ifndef __UNIQUE_ID 186 # define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __LINE__) 187 #endif 188 189 #endif /* __KERNEL__ */ 190 191 #endif /* __ASSEMBLY__ */ 192 193 #ifdef __KERNEL__ 194 /* 195 * Allow us to mark functions as 'deprecated' and have gcc emit a nice 196 * warning for each use, in hopes of speeding the functions removal. 197 * Usage is: 198 * int __deprecated foo(void) 199 */ 200 #ifndef __deprecated 201 # define __deprecated /* unimplemented */ 202 #endif 203 204 #ifdef MODULE 205 #define __deprecated_for_modules __deprecated 206 #else 207 #define __deprecated_for_modules 208 #endif 209 210 #ifndef __must_check 211 #define __must_check 212 #endif 213 214 #ifndef CONFIG_ENABLE_MUST_CHECK 215 #undef __must_check 216 #define __must_check 217 #endif 218 #ifndef CONFIG_ENABLE_WARN_DEPRECATED 219 #undef __deprecated 220 #undef __deprecated_for_modules 221 #define __deprecated 222 #define __deprecated_for_modules 223 #endif 224 225 /* 226 * Allow us to avoid 'defined but not used' warnings on functions and data, 227 * as well as force them to be emitted to the assembly file. 228 * 229 * As of gcc 3.4, static functions that are not marked with attribute((used)) 230 * may be elided from the assembly file. As of gcc 3.4, static data not so 231 * marked will not be elided, but this may change in a future gcc version. 232 * 233 * NOTE: Because distributions shipped with a backported unit-at-a-time 234 * compiler in gcc 3.3, we must define __used to be __attribute__((used)) 235 * for gcc >=3.3 instead of 3.4. 236 * 237 * In prior versions of gcc, such functions and data would be emitted, but 238 * would be warned about except with attribute((unused)). 239 * 240 * Mark functions that are referenced only in inline assembly as __used so 241 * the code is emitted even though it appears to be unreferenced. 242 */ 243 #ifndef __used 244 # define __used /* unimplemented */ 245 #endif 246 247 #ifndef __maybe_unused 248 # define __maybe_unused /* unimplemented */ 249 #endif 250 251 #ifndef __always_unused 252 # define __always_unused /* unimplemented */ 253 #endif 254 255 #ifndef noinline 256 #define noinline 257 #endif 258 259 /* 260 * Rather then using noinline to prevent stack consumption, use 261 * noinline_for_stack instead. For documentation reasons. 262 */ 263 #define noinline_for_stack noinline 264 265 #ifndef __always_inline 266 #define __always_inline inline 267 #endif 268 269 #endif /* __KERNEL__ */ 270 271 /* 272 * From the GCC manual: 273 * 274 * Many functions do not examine any values except their arguments, 275 * and have no effects except the return value. Basically this is 276 * just slightly more strict class than the `pure' attribute above, 277 * since function is not allowed to read global memory. 278 * 279 * Note that a function that has pointer arguments and examines the 280 * data pointed to must _not_ be declared `const'. Likewise, a 281 * function that calls a non-`const' function usually must not be 282 * `const'. It does not make sense for a `const' function to return 283 * `void'. 284 */ 285 #ifndef __attribute_const__ 286 # define __attribute_const__ /* unimplemented */ 287 #endif 288 289 /* 290 * Tell gcc if a function is cold. The compiler will assume any path 291 * directly leading to the call is unlikely. 292 */ 293 294 #ifndef __cold 295 #define __cold 296 #endif 297 298 /* Simple shorthand for a section definition */ 299 #ifndef __section 300 # define __section(S) __attribute__ ((__section__(#S))) 301 #endif 302 303 #ifndef __visible 304 #define __visible 305 #endif 306 307 /* Are two types/vars the same type (ignoring qualifiers)? */ 308 #ifndef __same_type 309 # define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b)) 310 #endif 311 312 /* Is this type a native word size -- useful for atomic operations */ 313 #ifndef __native_word 314 # define __native_word(t) (sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long)) 315 #endif 316 317 /* Compile time object size, -1 for unknown */ 318 #ifndef __compiletime_object_size 319 # define __compiletime_object_size(obj) -1 320 #endif 321 #ifndef __compiletime_warning 322 # define __compiletime_warning(message) 323 #endif 324 #ifndef __compiletime_error 325 # define __compiletime_error(message) 326 /* 327 * Sparse complains of variable sized arrays due to the temporary variable in 328 * __compiletime_assert. Unfortunately we can't just expand it out to make 329 * sparse see a constant array size without breaking compiletime_assert on old 330 * versions of GCC (e.g. 4.2.4), so hide the array from sparse altogether. 331 */ 332 # ifndef __CHECKER__ 333 # define __compiletime_error_fallback(condition) \ 334 do { ((void)sizeof(char[1 - 2 * condition])); } while (0) 335 # endif 336 #endif 337 #ifndef __compiletime_error_fallback 338 # define __compiletime_error_fallback(condition) do { } while (0) 339 #endif 340 341 #define __compiletime_assert(condition, msg, prefix, suffix) \ 342 do { \ 343 bool __cond = !(condition); \ 344 extern void prefix ## suffix(void) __compiletime_error(msg); \ 345 if (__cond) \ 346 prefix ## suffix(); \ 347 __compiletime_error_fallback(__cond); \ 348 } while (0) 349 350 #define _compiletime_assert(condition, msg, prefix, suffix) \ 351 __compiletime_assert(condition, msg, prefix, suffix) 352 353 /** 354 * compiletime_assert - break build and emit msg if condition is false 355 * @condition: a compile-time constant condition to check 356 * @msg: a message to emit if condition is false 357 * 358 * In tradition of POSIX assert, this macro will break the build if the 359 * supplied condition is *false*, emitting the supplied error message if the 360 * compiler has support to do so. 361 */ 362 #define compiletime_assert(condition, msg) \ 363 _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) 364 365 #define compiletime_assert_atomic_type(t) \ 366 compiletime_assert(__native_word(t), \ 367 "Need native word sized stores/loads for atomicity.") 368 369 /* 370 * Prevent the compiler from merging or refetching accesses. The compiler 371 * is also forbidden from reordering successive instances of ACCESS_ONCE(), 372 * but only when the compiler is aware of some particular ordering. One way 373 * to make the compiler aware of ordering is to put the two invocations of 374 * ACCESS_ONCE() in different C statements. 375 * 376 * This macro does absolutely -nothing- to prevent the CPU from reordering, 377 * merging, or refetching absolutely anything at any time. Its main intended 378 * use is to mediate communication between process-level code and irq/NMI 379 * handlers, all running on the same CPU. 380 */ 381 #define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x)) 382 383 /* Ignore/forbid kprobes attach on very low level functions marked by this attribute: */ 384 #ifdef CONFIG_KPROBES 385 # define __kprobes __attribute__((__section__(".kprobes.text"))) 386 # define nokprobe_inline __always_inline 387 #else 388 # define __kprobes 389 # define nokprobe_inline inline 390 #endif 391 #endif /* __LINUX_COMPILER_H */ 392