blob: 020ad16a0493e0348608d7f98c529d249cb6d609 [file] [log] [blame]
Graeme Russ95ffaba2010-04-24 00:05:49 +10001#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)))
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +09008# define __kernel __attribute__((address_space(0)))
Graeme Russ95ffaba2010-04-24 00:05:49 +10009# define __safe __attribute__((safe))
10# define __force __attribute__((force))
11# define __nocast __attribute__((nocast))
12# define __iomem __attribute__((noderef, address_space(2)))
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +090013# define __must_hold(x) __attribute__((context(x,1,1)))
Graeme Russ95ffaba2010-04-24 00:05:49 +100014# 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)
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +090019# define __percpu __attribute__((noderef, address_space(3)))
Tom Rini9b2c2822016-02-29 11:34:15 -050020# define __pmem __attribute__((noderef, address_space(5)))
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +090021#ifdef CONFIG_SPARSE_RCU_POINTER
22# define __rcu __attribute__((noderef, address_space(4)))
23#else
24# define __rcu
25#endif
Graeme Russ95ffaba2010-04-24 00:05:49 +100026extern void __chk_user_ptr(const volatile void __user *);
27extern 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)
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +090038# define __must_hold(x)
Graeme Russ95ffaba2010-04-24 00:05:49 +100039# 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)
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +090044# define __percpu
45# define __rcu
Tom Rini9b2c2822016-02-29 11:34:15 -050046# define __pmem
Graeme Russ95ffaba2010-04-24 00:05:49 +100047#endif
48
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +090049/* 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
Graeme Russ95ffaba2010-04-24 00:05:49 +100053#ifdef __KERNEL__
54
55#ifdef __GNUC__
56#include <linux/compiler-gcc.h>
57#endif
58
Tom Rini9b2c2822016-02-29 11:34:15 -050059#if defined(CC_USING_HOTPATCH) && !defined(__CHECKER__)
60#define notrace __attribute__((hotpatch(0,0)))
61#else
Graeme Russ95ffaba2010-04-24 00:05:49 +100062#define notrace __attribute__((no_instrument_function))
Tom Rini9b2c2822016-02-29 11:34:15 -050063#endif
Graeme Russ95ffaba2010-04-24 00:05:49 +100064
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
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +090072/* 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
Graeme Russ95ffaba2010-04-24 00:05:49 +100079/*
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
85struct 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__)
108void 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) \
Tom Rini9b2c2822016-02-29 11:34:15 -0500147 if (__builtin_constant_p(!!(cond)) ? !!(cond) : \
Graeme Russ95ffaba2010-04-24 00:05:49 +1000148 ({ \
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
Tom Rini9b2c2822016-02-29 11:34:15 -0500174#ifndef barrier_data
175# define barrier_data(ptr) barrier()
176#endif
177
Graeme Russ95ffaba2010-04-24 00:05:49 +1000178/* 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
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +0900190#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
Tom Rini9b2c2822016-02-29 11:34:15 -0500199#include <linux/types.h>
200
201#define __READ_ONCE_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
215static __always_inline
216void __read_once_size(const volatile void *p, void *res, int size)
217{
218 __READ_ONCE_SIZE;
219}
220
221#ifdef CONFIG_KASAN
222/*
223 * This function is not 'inline' because __no_sanitize_address confilcts
224 * with inlining. Attempt to inline it may cause a build failure.
225 * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368
226 * '__maybe_unused' allows us to avoid defined-but-not-used warnings.
227 */
228static __no_sanitize_address __maybe_unused
229void __read_once_size_nocheck(const volatile void *p, void *res, int size)
230{
231 __READ_ONCE_SIZE;
232}
233#else
234static __always_inline
235void __read_once_size_nocheck(const volatile void *p, void *res, int size)
236{
237 __READ_ONCE_SIZE;
238}
239#endif
240
241static __always_inline void __write_once_size(volatile void *p, void *res, int size)
242{
243 switch (size) {
244 case 1: *(volatile __u8 *)p = *(__u8 *)res; break;
245 case 2: *(volatile __u16 *)p = *(__u16 *)res; break;
246 case 4: *(volatile __u32 *)p = *(__u32 *)res; break;
247 case 8: *(volatile __u64 *)p = *(__u64 *)res; break;
248 default:
249 barrier();
250 __builtin_memcpy((void *)p, (const void *)res, size);
251 barrier();
252 }
253}
254
255/*
256 * Prevent the compiler from merging or refetching reads or writes. The
257 * compiler is also forbidden from reordering successive instances of
258 * READ_ONCE, WRITE_ONCE and ACCESS_ONCE (see below), but only when the
259 * compiler is aware of some particular ordering. One way to make the
260 * compiler aware of ordering is to put the two invocations of READ_ONCE,
261 * WRITE_ONCE or ACCESS_ONCE() in different C statements.
262 *
263 * In contrast to ACCESS_ONCE these two macros will also work on aggregate
264 * data types like structs or unions. If the size of the accessed data
265 * type exceeds the word size of the machine (e.g., 32 bits or 64 bits)
266 * READ_ONCE() and WRITE_ONCE() will fall back to memcpy and print a
267 * compile-time warning.
268 *
269 * Their two major use cases are: (1) Mediating communication between
270 * process-level code and irq/NMI handlers, all running on the same CPU,
271 * and (2) Ensuring that the compiler does not fold, spindle, or otherwise
272 * mutilate accesses that either do not require ordering or that interact
273 * with an explicit memory barrier or atomic instruction that provides the
274 * required ordering.
275 */
276
277#define __READ_ONCE(x, check) \
278({ \
279 union { typeof(x) __val; char __c[1]; } __u; \
280 if (check) \
281 __read_once_size(&(x), __u.__c, sizeof(x)); \
282 else \
283 __read_once_size_nocheck(&(x), __u.__c, sizeof(x)); \
284 __u.__val; \
285})
286#define READ_ONCE(x) __READ_ONCE(x, 1)
287
288/*
289 * Use READ_ONCE_NOCHECK() instead of READ_ONCE() if you need
290 * to hide memory access from KASAN.
291 */
292#define READ_ONCE_NOCHECK(x) __READ_ONCE(x, 0)
293
294#define WRITE_ONCE(x, val) \
295({ \
296 union { typeof(x) __val; char __c[1]; } __u = \
297 { .__val = (__force typeof(x)) (val) }; \
298 __write_once_size(&(x), __u.__c, sizeof(x)); \
299 __u.__val; \
300})
301
302/**
303 * smp_cond_acquire() - Spin wait for cond with ACQUIRE ordering
304 * @cond: boolean expression to wait for
305 *
306 * Equivalent to using smp_load_acquire() on the condition variable but employs
307 * the control dependency of the wait to reduce the barrier on many platforms.
308 *
309 * The control dependency provides a LOAD->STORE order, the additional RMB
310 * provides LOAD->LOAD order, together they provide LOAD->{LOAD,STORE} order,
311 * aka. ACQUIRE.
312 */
313#define smp_cond_acquire(cond) do { \
314 while (!(cond)) \
315 cpu_relax(); \
316 smp_rmb(); /* ctrl + rmb := acquire */ \
317} while (0)
318
Graeme Russ95ffaba2010-04-24 00:05:49 +1000319#endif /* __KERNEL__ */
320
321#endif /* __ASSEMBLY__ */
322
323#ifdef __KERNEL__
324/*
325 * Allow us to mark functions as 'deprecated' and have gcc emit a nice
326 * warning for each use, in hopes of speeding the functions removal.
327 * Usage is:
328 * int __deprecated foo(void)
329 */
330#ifndef __deprecated
331# define __deprecated /* unimplemented */
332#endif
333
334#ifdef MODULE
335#define __deprecated_for_modules __deprecated
336#else
337#define __deprecated_for_modules
338#endif
339
340#ifndef __must_check
341#define __must_check
342#endif
343
344#ifndef CONFIG_ENABLE_MUST_CHECK
345#undef __must_check
346#define __must_check
347#endif
348#ifndef CONFIG_ENABLE_WARN_DEPRECATED
349#undef __deprecated
350#undef __deprecated_for_modules
351#define __deprecated
352#define __deprecated_for_modules
353#endif
354
355/*
356 * Allow us to avoid 'defined but not used' warnings on functions and data,
357 * as well as force them to be emitted to the assembly file.
358 *
359 * As of gcc 3.4, static functions that are not marked with attribute((used))
360 * may be elided from the assembly file. As of gcc 3.4, static data not so
361 * marked will not be elided, but this may change in a future gcc version.
362 *
363 * NOTE: Because distributions shipped with a backported unit-at-a-time
364 * compiler in gcc 3.3, we must define __used to be __attribute__((used))
365 * for gcc >=3.3 instead of 3.4.
366 *
367 * In prior versions of gcc, such functions and data would be emitted, but
368 * would be warned about except with attribute((unused)).
369 *
370 * Mark functions that are referenced only in inline assembly as __used so
371 * the code is emitted even though it appears to be unreferenced.
372 */
373#ifndef __used
374# define __used /* unimplemented */
375#endif
376
377#ifndef __maybe_unused
378# define __maybe_unused /* unimplemented */
379#endif
380
381#ifndef __always_unused
382# define __always_unused /* unimplemented */
383#endif
384
385#ifndef noinline
386#define noinline
387#endif
388
389/*
390 * Rather then using noinline to prevent stack consumption, use
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +0900391 * noinline_for_stack instead. For documentation reasons.
Graeme Russ95ffaba2010-04-24 00:05:49 +1000392 */
393#define noinline_for_stack noinline
394
395#ifndef __always_inline
396#define __always_inline inline
397#endif
398
399#endif /* __KERNEL__ */
400
401/*
402 * From the GCC manual:
403 *
404 * Many functions do not examine any values except their arguments,
405 * and have no effects except the return value. Basically this is
406 * just slightly more strict class than the `pure' attribute above,
407 * since function is not allowed to read global memory.
408 *
409 * Note that a function that has pointer arguments and examines the
410 * data pointed to must _not_ be declared `const'. Likewise, a
411 * function that calls a non-`const' function usually must not be
412 * `const'. It does not make sense for a `const' function to return
413 * `void'.
414 */
415#ifndef __attribute_const__
416# define __attribute_const__ /* unimplemented */
417#endif
418
419/*
420 * Tell gcc if a function is cold. The compiler will assume any path
421 * directly leading to the call is unlikely.
422 */
423
424#ifndef __cold
425#define __cold
426#endif
427
428/* Simple shorthand for a section definition */
429#ifndef __section
430# define __section(S) __attribute__ ((__section__(#S)))
431#endif
432
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +0900433#ifndef __visible
434#define __visible
435#endif
436
Tom Rini9b2c2822016-02-29 11:34:15 -0500437/*
438 * Assume alignment of return value.
439 */
440#ifndef __assume_aligned
441#define __assume_aligned(a, ...)
442#endif
443
444
Graeme Russ95ffaba2010-04-24 00:05:49 +1000445/* Are two types/vars the same type (ignoring qualifiers)? */
446#ifndef __same_type
447# define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
448#endif
449
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +0900450/* Is this type a native word size -- useful for atomic operations */
451#ifndef __native_word
Tom Rini9b2c2822016-02-29 11:34:15 -0500452# define __native_word(t) (sizeof(t) == sizeof(char) || sizeof(t) == sizeof(short) || sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long))
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +0900453#endif
454
Graeme Russ95ffaba2010-04-24 00:05:49 +1000455/* Compile time object size, -1 for unknown */
456#ifndef __compiletime_object_size
457# define __compiletime_object_size(obj) -1
458#endif
459#ifndef __compiletime_warning
460# define __compiletime_warning(message)
461#endif
462#ifndef __compiletime_error
463# define __compiletime_error(message)
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +0900464/*
465 * Sparse complains of variable sized arrays due to the temporary variable in
466 * __compiletime_assert. Unfortunately we can't just expand it out to make
467 * sparse see a constant array size without breaking compiletime_assert on old
468 * versions of GCC (e.g. 4.2.4), so hide the array from sparse altogether.
469 */
470# ifndef __CHECKER__
471# define __compiletime_error_fallback(condition) \
472 do { ((void)sizeof(char[1 - 2 * condition])); } while (0)
473# endif
Graeme Russ95ffaba2010-04-24 00:05:49 +1000474#endif
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +0900475#ifndef __compiletime_error_fallback
476# define __compiletime_error_fallback(condition) do { } while (0)
477#endif
478
479#define __compiletime_assert(condition, msg, prefix, suffix) \
480 do { \
481 bool __cond = !(condition); \
482 extern void prefix ## suffix(void) __compiletime_error(msg); \
483 if (__cond) \
484 prefix ## suffix(); \
485 __compiletime_error_fallback(__cond); \
486 } while (0)
487
488#define _compiletime_assert(condition, msg, prefix, suffix) \
489 __compiletime_assert(condition, msg, prefix, suffix)
490
491/**
492 * compiletime_assert - break build and emit msg if condition is false
493 * @condition: a compile-time constant condition to check
494 * @msg: a message to emit if condition is false
495 *
496 * In tradition of POSIX assert, this macro will break the build if the
497 * supplied condition is *false*, emitting the supplied error message if the
498 * compiler has support to do so.
499 */
500#define compiletime_assert(condition, msg) \
501 _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
502
503#define compiletime_assert_atomic_type(t) \
504 compiletime_assert(__native_word(t), \
505 "Need native word sized stores/loads for atomicity.")
Graeme Russ95ffaba2010-04-24 00:05:49 +1000506
507/*
508 * Prevent the compiler from merging or refetching accesses. The compiler
509 * is also forbidden from reordering successive instances of ACCESS_ONCE(),
510 * but only when the compiler is aware of some particular ordering. One way
511 * to make the compiler aware of ordering is to put the two invocations of
512 * ACCESS_ONCE() in different C statements.
513 *
Tom Rini9b2c2822016-02-29 11:34:15 -0500514 * ACCESS_ONCE will only work on scalar types. For union types, ACCESS_ONCE
515 * on a union member will work as long as the size of the member matches the
516 * size of the union and the size is smaller than word size.
517 *
518 * The major use cases of ACCESS_ONCE used to be (1) Mediating communication
519 * between process-level code and irq/NMI handlers, all running on the same CPU,
520 * and (2) Ensuring that the compiler does not fold, spindle, or otherwise
521 * mutilate accesses that either do not require ordering or that interact
522 * with an explicit memory barrier or atomic instruction that provides the
523 * required ordering.
524 *
525 * If possible use READ_ONCE()/WRITE_ONCE() instead.
Graeme Russ95ffaba2010-04-24 00:05:49 +1000526 */
Tom Rini9b2c2822016-02-29 11:34:15 -0500527#define __ACCESS_ONCE(x) ({ \
528 __maybe_unused typeof(x) __var = (__force typeof(x)) 0; \
529 (volatile typeof(x) *)&(x); })
530#define ACCESS_ONCE(x) (*__ACCESS_ONCE(x))
531
532/**
533 * lockless_dereference() - safely load a pointer for later dereference
534 * @p: The pointer to load
535 *
536 * Similar to rcu_dereference(), but for situations where the pointed-to
537 * object's lifetime is managed by something other than RCU. That
538 * "something other" might be reference counting or simple immortality.
539 */
540#define lockless_dereference(p) \
541({ \
542 typeof(p) _________p1 = READ_ONCE(p); \
543 smp_read_barrier_depends(); /* Dependency order vs. p above. */ \
544 (_________p1); \
545})
Graeme Russ95ffaba2010-04-24 00:05:49 +1000546
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +0900547/* Ignore/forbid kprobes attach on very low level functions marked by this attribute: */
548#ifdef CONFIG_KPROBES
549# define __kprobes __attribute__((__section__(".kprobes.text")))
550# define nokprobe_inline __always_inline
551#else
552# define __kprobes
553# define nokprobe_inline inline
554#endif
Graeme Russ95ffaba2010-04-24 00:05:49 +1000555#endif /* __LINUX_COMPILER_H */