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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 | # define __pmem __attribute__((noderef, address_space(5))) | |
21 | #ifdef CONFIG_SPARSE_RCU_POINTER | |
22 | # define __rcu __attribute__((noderef, address_space(4))) | |
23 | #else | |
24 | # define __rcu | |
25 | #endif | |
26 | extern void __chk_user_ptr(const volatile void __user *); | |
27 | extern void __chk_io_ptr(const volatile void __iomem *); | |
28 | #else | |
29 | # define __user | |
30 | # define __kernel | |
31 | # define __safe | |
32 | # define __force | |
33 | # define __nocast | |
34 | # define __iomem | |
35 | # define __chk_user_ptr(x) (void)0 | |
36 | # define __chk_io_ptr(x) (void)0 | |
37 | # define __builtin_warning(x, y...) (1) | |
38 | # define __must_hold(x) | |
39 | # define __acquires(x) | |
40 | # define __releases(x) | |
41 | # define __acquire(x) (void)0 | |
42 | # define __release(x) (void)0 | |
43 | # define __cond_lock(x,c) (c) | |
44 | # define __percpu | |
45 | # define __rcu | |
46 | # define __pmem | |
47 | #endif | |
48 | ||
49 | /* Indirect macros required for expanded argument pasting, eg. __LINE__. */ | |
50 | #define ___PASTE(a,b) a##b | |
51 | #define __PASTE(a,b) ___PASTE(a,b) | |
52 | ||
53 | #ifdef __KERNEL__ | |
54 | ||
55 | #ifdef __GNUC__ | |
56 | #include <linux/compiler-gcc.h> | |
57 | #endif | |
58 | ||
59 | #ifdef CC_USING_HOTPATCH | |
60 | #define notrace __attribute__((hotpatch(0,0))) | |
61 | #else | |
62 | #define notrace __attribute__((no_instrument_function)) | |
63 | #endif | |
64 | ||
65 | /* Intel compiler defines __GNUC__. So we will overwrite implementations | |
66 | * coming from above header files here | |
67 | */ | |
68 | #ifdef __INTEL_COMPILER | |
69 | # include <linux/compiler-intel.h> | |
70 | #endif | |
71 | ||
72 | /* Clang compiler defines __GNUC__. So we will overwrite implementations | |
73 | * coming from above header files here | |
74 | */ | |
75 | #ifdef __clang__ | |
76 | #include <linux/compiler-clang.h> | |
77 | #endif | |
78 | ||
79 | /* | |
80 | * Generic compiler-dependent macros required for kernel | |
81 | * build go below this comment. Actual compiler/compiler version | |
82 | * specific implementations come from the above header files | |
83 | */ | |
84 | ||
85 | struct ftrace_branch_data { | |
86 | const char *func; | |
87 | const char *file; | |
88 | unsigned line; | |
89 | union { | |
90 | struct { | |
91 | unsigned long correct; | |
92 | unsigned long incorrect; | |
93 | }; | |
94 | struct { | |
95 | unsigned long miss; | |
96 | unsigned long hit; | |
97 | }; | |
98 | unsigned long miss_hit[2]; | |
99 | }; | |
100 | }; | |
101 | ||
102 | /* | |
103 | * Note: DISABLE_BRANCH_PROFILING can be used by special lowlevel code | |
104 | * to disable branch tracing on a per file basis. | |
105 | */ | |
106 | #if defined(CONFIG_TRACE_BRANCH_PROFILING) \ | |
107 | && !defined(DISABLE_BRANCH_PROFILING) && !defined(__CHECKER__) | |
108 | void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect); | |
109 | ||
110 | #define likely_notrace(x) __builtin_expect(!!(x), 1) | |
111 | #define unlikely_notrace(x) __builtin_expect(!!(x), 0) | |
112 | ||
113 | #define __branch_check__(x, expect) ({ \ | |
114 | int ______r; \ | |
115 | static struct ftrace_branch_data \ | |
116 | __attribute__((__aligned__(4))) \ | |
117 | __attribute__((section("_ftrace_annotated_branch"))) \ | |
118 | ______f = { \ | |
119 | .func = __func__, \ | |
120 | .file = __FILE__, \ | |
121 | .line = __LINE__, \ | |
122 | }; \ | |
123 | ______r = likely_notrace(x); \ | |
124 | ftrace_likely_update(&______f, ______r, expect); \ | |
125 | ______r; \ | |
126 | }) | |
127 | ||
128 | /* | |
129 | * Using __builtin_constant_p(x) to ignore cases where the return | |
130 | * value is always the same. This idea is taken from a similar patch | |
131 | * written by Daniel Walker. | |
132 | */ | |
133 | # ifndef likely | |
134 | # define likely(x) (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 1)) | |
135 | # endif | |
136 | # ifndef unlikely | |
137 | # define unlikely(x) (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 0)) | |
138 | # endif | |
139 | ||
140 | #ifdef CONFIG_PROFILE_ALL_BRANCHES | |
141 | /* | |
142 | * "Define 'is'", Bill Clinton | |
143 | * "Define 'if'", Steven Rostedt | |
144 | */ | |
145 | #define if(cond, ...) __trace_if( (cond , ## __VA_ARGS__) ) | |
146 | #define __trace_if(cond) \ | |
147 | if (__builtin_constant_p((cond)) ? !!(cond) : \ | |
148 | ({ \ | |
149 | int ______r; \ | |
150 | static struct ftrace_branch_data \ | |
151 | __attribute__((__aligned__(4))) \ | |
152 | __attribute__((section("_ftrace_branch"))) \ | |
153 | ______f = { \ | |
154 | .func = __func__, \ | |
155 | .file = __FILE__, \ | |
156 | .line = __LINE__, \ | |
157 | }; \ | |
158 | ______r = !!(cond); \ | |
159 | ______f.miss_hit[______r]++; \ | |
160 | ______r; \ | |
161 | })) | |
162 | #endif /* CONFIG_PROFILE_ALL_BRANCHES */ | |
163 | ||
164 | #else | |
165 | # define likely(x) __builtin_expect(!!(x), 1) | |
166 | # define unlikely(x) __builtin_expect(!!(x), 0) | |
167 | #endif | |
168 | ||
169 | /* Optimization barrier */ | |
170 | #ifndef barrier | |
171 | # define barrier() __memory_barrier() | |
172 | #endif | |
173 | ||
174 | #ifndef barrier_data | |
175 | # define barrier_data(ptr) barrier() | |
176 | #endif | |
177 | ||
178 | /* Unreachable code */ | |
179 | #ifndef unreachable | |
180 | # define unreachable() do { } while (1) | |
181 | #endif | |
182 | ||
183 | #ifndef RELOC_HIDE | |
184 | # define RELOC_HIDE(ptr, off) \ | |
185 | ({ unsigned long __ptr; \ | |
186 | __ptr = (unsigned long) (ptr); \ | |
187 | (typeof(ptr)) (__ptr + (off)); }) | |
188 | #endif | |
189 | ||
190 | #ifndef OPTIMIZER_HIDE_VAR | |
191 | #define OPTIMIZER_HIDE_VAR(var) barrier() | |
192 | #endif | |
193 | ||
194 | /* Not-quite-unique ID. */ | |
195 | #ifndef __UNIQUE_ID | |
196 | # define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __LINE__) | |
197 | #endif | |
198 | ||
199 | #include <uapi/linux/types.h> | |
200 | ||
201 | static __always_inline void __read_once_size(const volatile void *p, void *res, int size) | |
202 | { | |
203 | switch (size) { | |
204 | case 1: *(__u8 *)res = *(volatile __u8 *)p; break; | |
205 | case 2: *(__u16 *)res = *(volatile __u16 *)p; break; | |
206 | case 4: *(__u32 *)res = *(volatile __u32 *)p; break; | |
207 | case 8: *(__u64 *)res = *(volatile __u64 *)p; break; | |
208 | default: | |
209 | barrier(); | |
210 | __builtin_memcpy((void *)res, (const void *)p, size); | |
211 | barrier(); | |
212 | } | |
213 | } | |
214 | ||
215 | static __always_inline void __write_once_size(volatile void *p, void *res, int size) | |
216 | { | |
217 | switch (size) { | |
218 | case 1: *(volatile __u8 *)p = *(__u8 *)res; break; | |
219 | case 2: *(volatile __u16 *)p = *(__u16 *)res; break; | |
220 | case 4: *(volatile __u32 *)p = *(__u32 *)res; break; | |
221 | case 8: *(volatile __u64 *)p = *(__u64 *)res; break; | |
222 | default: | |
223 | barrier(); | |
224 | __builtin_memcpy((void *)p, (const void *)res, size); | |
225 | barrier(); | |
226 | } | |
227 | } | |
228 | ||
229 | /* | |
230 | * Prevent the compiler from merging or refetching reads or writes. The | |
231 | * compiler is also forbidden from reordering successive instances of | |
232 | * READ_ONCE, WRITE_ONCE and ACCESS_ONCE (see below), but only when the | |
233 | * compiler is aware of some particular ordering. One way to make the | |
234 | * compiler aware of ordering is to put the two invocations of READ_ONCE, | |
235 | * WRITE_ONCE or ACCESS_ONCE() in different C statements. | |
236 | * | |
237 | * In contrast to ACCESS_ONCE these two macros will also work on aggregate | |
238 | * data types like structs or unions. If the size of the accessed data | |
239 | * type exceeds the word size of the machine (e.g., 32 bits or 64 bits) | |
240 | * READ_ONCE() and WRITE_ONCE() will fall back to memcpy and print a | |
241 | * compile-time warning. | |
242 | * | |
243 | * Their two major use cases are: (1) Mediating communication between | |
244 | * process-level code and irq/NMI handlers, all running on the same CPU, | |
245 | * and (2) Ensuring that the compiler does not fold, spindle, or otherwise | |
246 | * mutilate accesses that either do not require ordering or that interact | |
247 | * with an explicit memory barrier or atomic instruction that provides the | |
248 | * required ordering. | |
249 | */ | |
250 | ||
251 | #define READ_ONCE(x) \ | |
252 | ({ union { typeof(x) __val; char __c[1]; } __u; __read_once_size(&(x), __u.__c, sizeof(x)); __u.__val; }) | |
253 | ||
254 | #define WRITE_ONCE(x, val) \ | |
255 | ({ \ | |
256 | union { typeof(x) __val; char __c[1]; } __u = \ | |
257 | { .__val = (__force typeof(x)) (val) }; \ | |
258 | __write_once_size(&(x), __u.__c, sizeof(x)); \ | |
259 | __u.__val; \ | |
260 | }) | |
261 | ||
262 | /** | |
263 | * READ_ONCE_CTRL - Read a value heading a control dependency | |
264 | * @x: The value to be read, heading the control dependency | |
265 | * | |
266 | * Control dependencies are tricky. See Documentation/memory-barriers.txt | |
267 | * for important information on how to use them. Note that in many cases, | |
268 | * use of smp_load_acquire() will be much simpler. Control dependencies | |
269 | * should be avoided except on the hottest of hotpaths. | |
270 | */ | |
271 | #define READ_ONCE_CTRL(x) \ | |
272 | ({ \ | |
273 | typeof(x) __val = READ_ONCE(x); \ | |
274 | smp_read_barrier_depends(); /* Enforce control dependency. */ \ | |
275 | __val; \ | |
276 | }) | |
277 | ||
278 | #endif /* __KERNEL__ */ | |
279 | ||
280 | #endif /* __ASSEMBLY__ */ | |
281 | ||
282 | #ifdef __KERNEL__ | |
283 | /* | |
284 | * Allow us to mark functions as 'deprecated' and have gcc emit a nice | |
285 | * warning for each use, in hopes of speeding the functions removal. | |
286 | * Usage is: | |
287 | * int __deprecated foo(void) | |
288 | */ | |
289 | #ifndef __deprecated | |
290 | # define __deprecated /* unimplemented */ | |
291 | #endif | |
292 | ||
293 | #ifdef MODULE | |
294 | #define __deprecated_for_modules __deprecated | |
295 | #else | |
296 | #define __deprecated_for_modules | |
297 | #endif | |
298 | ||
299 | #ifndef __must_check | |
300 | #define __must_check | |
301 | #endif | |
302 | ||
303 | #ifndef CONFIG_ENABLE_MUST_CHECK | |
304 | #undef __must_check | |
305 | #define __must_check | |
306 | #endif | |
307 | #ifndef CONFIG_ENABLE_WARN_DEPRECATED | |
308 | #undef __deprecated | |
309 | #undef __deprecated_for_modules | |
310 | #define __deprecated | |
311 | #define __deprecated_for_modules | |
312 | #endif | |
313 | ||
314 | /* | |
315 | * Allow us to avoid 'defined but not used' warnings on functions and data, | |
316 | * as well as force them to be emitted to the assembly file. | |
317 | * | |
318 | * As of gcc 3.4, static functions that are not marked with attribute((used)) | |
319 | * may be elided from the assembly file. As of gcc 3.4, static data not so | |
320 | * marked will not be elided, but this may change in a future gcc version. | |
321 | * | |
322 | * NOTE: Because distributions shipped with a backported unit-at-a-time | |
323 | * compiler in gcc 3.3, we must define __used to be __attribute__((used)) | |
324 | * for gcc >=3.3 instead of 3.4. | |
325 | * | |
326 | * In prior versions of gcc, such functions and data would be emitted, but | |
327 | * would be warned about except with attribute((unused)). | |
328 | * | |
329 | * Mark functions that are referenced only in inline assembly as __used so | |
330 | * the code is emitted even though it appears to be unreferenced. | |
331 | */ | |
332 | #ifndef __used | |
333 | # define __used /* unimplemented */ | |
334 | #endif | |
335 | ||
336 | #ifndef __maybe_unused | |
337 | # define __maybe_unused /* unimplemented */ | |
338 | #endif | |
339 | ||
340 | #ifndef __always_unused | |
341 | # define __always_unused /* unimplemented */ | |
342 | #endif | |
343 | ||
344 | #ifndef noinline | |
345 | #define noinline | |
346 | #endif | |
347 | ||
348 | /* | |
349 | * Rather then using noinline to prevent stack consumption, use | |
350 | * noinline_for_stack instead. For documentation reasons. | |
351 | */ | |
352 | #define noinline_for_stack noinline | |
353 | ||
354 | #ifndef __always_inline | |
355 | #define __always_inline inline | |
356 | #endif | |
357 | ||
358 | #endif /* __KERNEL__ */ | |
359 | ||
360 | /* | |
361 | * From the GCC manual: | |
362 | * | |
363 | * Many functions do not examine any values except their arguments, | |
364 | * and have no effects except the return value. Basically this is | |
365 | * just slightly more strict class than the `pure' attribute above, | |
366 | * since function is not allowed to read global memory. | |
367 | * | |
368 | * Note that a function that has pointer arguments and examines the | |
369 | * data pointed to must _not_ be declared `const'. Likewise, a | |
370 | * function that calls a non-`const' function usually must not be | |
371 | * `const'. It does not make sense for a `const' function to return | |
372 | * `void'. | |
373 | */ | |
374 | #ifndef __attribute_const__ | |
375 | # define __attribute_const__ /* unimplemented */ | |
376 | #endif | |
377 | ||
378 | /* | |
379 | * Tell gcc if a function is cold. The compiler will assume any path | |
380 | * directly leading to the call is unlikely. | |
381 | */ | |
382 | ||
383 | #ifndef __cold | |
384 | #define __cold | |
385 | #endif | |
386 | ||
387 | /* Simple shorthand for a section definition */ | |
388 | #ifndef __section | |
389 | # define __section(S) __attribute__ ((__section__(#S))) | |
390 | #endif | |
391 | ||
392 | #ifndef __visible | |
393 | #define __visible | |
394 | #endif | |
395 | ||
396 | /* Are two types/vars the same type (ignoring qualifiers)? */ | |
397 | #ifndef __same_type | |
398 | # define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b)) | |
399 | #endif | |
400 | ||
401 | /* Is this type a native word size -- useful for atomic operations */ | |
402 | #ifndef __native_word | |
403 | # define __native_word(t) (sizeof(t) == sizeof(char) || sizeof(t) == sizeof(short) || sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long)) | |
404 | #endif | |
405 | ||
406 | /* Compile time object size, -1 for unknown */ | |
407 | #ifndef __compiletime_object_size | |
408 | # define __compiletime_object_size(obj) -1 | |
409 | #endif | |
410 | #ifndef __compiletime_warning | |
411 | # define __compiletime_warning(message) | |
412 | #endif | |
413 | #ifndef __compiletime_error | |
414 | # define __compiletime_error(message) | |
415 | /* | |
416 | * Sparse complains of variable sized arrays due to the temporary variable in | |
417 | * __compiletime_assert. Unfortunately we can't just expand it out to make | |
418 | * sparse see a constant array size without breaking compiletime_assert on old | |
419 | * versions of GCC (e.g. 4.2.4), so hide the array from sparse altogether. | |
420 | */ | |
421 | # ifndef __CHECKER__ | |
422 | # define __compiletime_error_fallback(condition) \ | |
423 | do { ((void)sizeof(char[1 - 2 * condition])); } while (0) | |
424 | # endif | |
425 | #endif | |
426 | #ifndef __compiletime_error_fallback | |
427 | # define __compiletime_error_fallback(condition) do { } while (0) | |
428 | #endif | |
429 | ||
430 | #define __compiletime_assert(condition, msg, prefix, suffix) \ | |
431 | do { \ | |
432 | bool __cond = !(condition); \ | |
433 | extern void prefix ## suffix(void) __compiletime_error(msg); \ | |
434 | if (__cond) \ | |
435 | prefix ## suffix(); \ | |
436 | __compiletime_error_fallback(__cond); \ | |
437 | } while (0) | |
438 | ||
439 | #define _compiletime_assert(condition, msg, prefix, suffix) \ | |
440 | __compiletime_assert(condition, msg, prefix, suffix) | |
441 | ||
442 | /** | |
443 | * compiletime_assert - break build and emit msg if condition is false | |
444 | * @condition: a compile-time constant condition to check | |
445 | * @msg: a message to emit if condition is false | |
446 | * | |
447 | * In tradition of POSIX assert, this macro will break the build if the | |
448 | * supplied condition is *false*, emitting the supplied error message if the | |
449 | * compiler has support to do so. | |
450 | */ | |
451 | #define compiletime_assert(condition, msg) \ | |
452 | _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) | |
453 | ||
454 | #define compiletime_assert_atomic_type(t) \ | |
455 | compiletime_assert(__native_word(t), \ | |
456 | "Need native word sized stores/loads for atomicity.") | |
457 | ||
458 | /* | |
459 | * Prevent the compiler from merging or refetching accesses. The compiler | |
460 | * is also forbidden from reordering successive instances of ACCESS_ONCE(), | |
461 | * but only when the compiler is aware of some particular ordering. One way | |
462 | * to make the compiler aware of ordering is to put the two invocations of | |
463 | * ACCESS_ONCE() in different C statements. | |
464 | * | |
465 | * ACCESS_ONCE will only work on scalar types. For union types, ACCESS_ONCE | |
466 | * on a union member will work as long as the size of the member matches the | |
467 | * size of the union and the size is smaller than word size. | |
468 | * | |
469 | * The major use cases of ACCESS_ONCE used to be (1) Mediating communication | |
470 | * between process-level code and irq/NMI handlers, all running on the same CPU, | |
471 | * and (2) Ensuring that the compiler does not fold, spindle, or otherwise | |
472 | * mutilate accesses that either do not require ordering or that interact | |
473 | * with an explicit memory barrier or atomic instruction that provides the | |
474 | * required ordering. | |
475 | * | |
476 | * If possible use READ_ONCE()/WRITE_ONCE() instead. | |
477 | */ | |
478 | #define __ACCESS_ONCE(x) ({ \ | |
479 | __maybe_unused typeof(x) __var = (__force typeof(x)) 0; \ | |
480 | (volatile typeof(x) *)&(x); }) | |
481 | #define ACCESS_ONCE(x) (*__ACCESS_ONCE(x)) | |
482 | ||
483 | /** | |
484 | * lockless_dereference() - safely load a pointer for later dereference | |
485 | * @p: The pointer to load | |
486 | * | |
487 | * Similar to rcu_dereference(), but for situations where the pointed-to | |
488 | * object's lifetime is managed by something other than RCU. That | |
489 | * "something other" might be reference counting or simple immortality. | |
490 | */ | |
491 | #define lockless_dereference(p) \ | |
492 | ({ \ | |
493 | typeof(p) _________p1 = READ_ONCE(p); \ | |
494 | smp_read_barrier_depends(); /* Dependency order vs. p above. */ \ | |
495 | (_________p1); \ | |
496 | }) | |
497 | ||
498 | /* Ignore/forbid kprobes attach on very low level functions marked by this attribute: */ | |
499 | #ifdef CONFIG_KPROBES | |
500 | # define __kprobes __attribute__((__section__(".kprobes.text"))) | |
501 | # define nokprobe_inline __always_inline | |
502 | #else | |
503 | # define __kprobes | |
504 | # define nokprobe_inline inline | |
505 | #endif | |
506 | #endif /* __LINUX_COMPILER_H */ |