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CommitLineData
1da177e4
LT
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)))
e0fdb0e0 8# define __kernel __attribute__((address_space(0)))
1da177e4
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9# define __safe __attribute__((safe))
10# define __force __attribute__((force))
11# define __nocast __attribute__((nocast))
12# define __iomem __attribute__((noderef, address_space(2)))
8529091e 13# define __must_hold(x) __attribute__((context(x,1,1)))
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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)
dcc8e559 18# define __cond_lock(x,c) ((c) ? ({ __acquire(x); 1; }) : 0)
e0fdb0e0 19# define __percpu __attribute__((noderef, address_space(3)))
31f02455 20# define __pmem __attribute__((noderef, address_space(5)))
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21#ifdef CONFIG_SPARSE_RCU_POINTER
22# define __rcu __attribute__((noderef, address_space(4)))
23#else
71d1d5c7 24# define __rcu
ca5ecddf 25#endif
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AV
26extern void __chk_user_ptr(const volatile void __user *);
27extern void __chk_io_ptr(const volatile void __iomem *);
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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)
8529091e 38# define __must_hold(x)
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39# define __acquires(x)
40# define __releases(x)
41# define __acquire(x) (void)0
42# define __release(x) (void)0
dcc8e559 43# define __cond_lock(x,c) (c)
e0fdb0e0 44# define __percpu
71d1d5c7 45# define __rcu
61031952 46# define __pmem
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47#endif
48
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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
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53#ifdef __KERNEL__
54
f153b821
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55#ifdef __GNUC__
56#include <linux/compiler-gcc.h>
1da177e4
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57#endif
58
61f55214
HC
59#ifdef CC_USING_HOTPATCH
60#define notrace __attribute__((hotpatch(0,0)))
61#else
28614889 62#define notrace __attribute__((no_instrument_function))
61f55214 63#endif
28614889 64
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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
565cbdc2
MC
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
1da177e4
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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
2ed84eeb 85struct ftrace_branch_data {
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86 const char *func;
87 const char *file;
88 unsigned line;
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SR
89 union {
90 struct {
91 unsigned long correct;
92 unsigned long incorrect;
93 };
94 struct {
95 unsigned long miss;
96 unsigned long hit;
97 };
97e7e4f3 98 unsigned long miss_hit[2];
2bcd521a 99 };
1f0d69a9 100};
2ed84eeb
SR
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 */
d9ad8bc0
BVA
106#if defined(CONFIG_TRACE_BRANCH_PROFILING) \
107 && !defined(DISABLE_BRANCH_PROFILING) && !defined(__CHECKER__)
2ed84eeb 108void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
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SR
109
110#define likely_notrace(x) __builtin_expect(!!(x), 1)
111#define unlikely_notrace(x) __builtin_expect(!!(x), 0)
112
45b79749 113#define __branch_check__(x, expect) ({ \
1f0d69a9 114 int ______r; \
2ed84eeb 115 static struct ftrace_branch_data \
1f0d69a9 116 __attribute__((__aligned__(4))) \
45b79749 117 __attribute__((section("_ftrace_annotated_branch"))) \
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118 ______f = { \
119 .func = __func__, \
120 .file = __FILE__, \
121 .line = __LINE__, \
122 }; \
1f0d69a9 123 ______r = likely_notrace(x); \
45b79749 124 ftrace_likely_update(&______f, ______r, expect); \
1f0d69a9
SR
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
45b79749 134# define likely(x) (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 1))
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135# endif
136# ifndef unlikely
45b79749 137# define unlikely(x) (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 0))
1f0d69a9 138# endif
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139
140#ifdef CONFIG_PROFILE_ALL_BRANCHES
141/*
142 * "Define 'is'", Bill Clinton
143 * "Define 'if'", Steven Rostedt
144 */
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LT
145#define if(cond, ...) __trace_if( (cond , ## __VA_ARGS__) )
146#define __trace_if(cond) \
147 if (__builtin_constant_p((cond)) ? !!(cond) : \
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SR
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); \
97e7e4f3 159 ______f.miss_hit[______r]++; \
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160 ______r; \
161 }))
162#endif /* CONFIG_PROFILE_ALL_BRANCHES */
163
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164#else
165# define likely(x) __builtin_expect(!!(x), 1)
166# define unlikely(x) __builtin_expect(!!(x), 0)
167#endif
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168
169/* Optimization barrier */
170#ifndef barrier
171# define barrier() __memory_barrier()
172#endif
173
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174#ifndef barrier_data
175# define barrier_data(ptr) barrier()
176#endif
177
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178/* Unreachable code */
179#ifndef unreachable
180# define unreachable() do { } while (1)
181#endif
182
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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
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190#ifndef OPTIMIZER_HIDE_VAR
191#define OPTIMIZER_HIDE_VAR(var) barrier()
192#endif
193
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194/* Not-quite-unique ID. */
195#ifndef __UNIQUE_ID
196# define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __LINE__)
197#endif
198
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199#include <uapi/linux/types.h>
200
dd369297 201static __always_inline void __read_once_size(const volatile void *p, void *res, int size)
230fa253
CB
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;
230fa253 207 case 8: *(__u64 *)res = *(volatile __u64 *)p; break;
230fa253
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208 default:
209 barrier();
210 __builtin_memcpy((void *)res, (const void *)p, size);
230fa253
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211 barrier();
212 }
213}
214
43239cbe 215static __always_inline void __write_once_size(volatile void *p, void *res, int size)
230fa253
CB
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;
230fa253 221 case 8: *(volatile __u64 *)p = *(__u64 *)res; break;
230fa253
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222 default:
223 barrier();
224 __builtin_memcpy((void *)p, (const void *)res, size);
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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
43239cbe 232 * READ_ONCE, WRITE_ONCE and ACCESS_ONCE (see below), but only when the
230fa253
CB
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,
43239cbe 235 * WRITE_ONCE or ACCESS_ONCE() in different C statements.
230fa253
CB
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)
43239cbe 240 * READ_ONCE() and WRITE_ONCE() will fall back to memcpy and print a
230fa253
CB
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) \
dd369297 252 ({ union { typeof(x) __val; char __c[1]; } __u; __read_once_size(&(x), __u.__c, sizeof(x)); __u.__val; })
230fa253 253
43239cbe 254#define WRITE_ONCE(x, val) \
ba33034f
CB
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})
230fa253 261
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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
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278#endif /* __KERNEL__ */
279
280#endif /* __ASSEMBLY__ */
281
4f79c3ff 282#ifdef __KERNEL__
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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
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293#ifdef MODULE
294#define __deprecated_for_modules __deprecated
295#else
296#define __deprecated_for_modules
297#endif
298
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299#ifndef __must_check
300#define __must_check
301#endif
302
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AM
303#ifndef CONFIG_ENABLE_MUST_CHECK
304#undef __must_check
305#define __must_check
306#endif
de488443
JG
307#ifndef CONFIG_ENABLE_WARN_DEPRECATED
308#undef __deprecated
309#undef __deprecated_for_modules
310#define __deprecated
311#define __deprecated_for_modules
312#endif
cebc04ba 313
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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 *
0d7ebbbc
DR
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
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320 * marked will not be elided, but this may change in a future gcc version.
321 *
0d7ebbbc
DR
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 *
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326 * In prior versions of gcc, such functions and data would be emitted, but
327 * would be warned about except with attribute((unused)).
0d7ebbbc
DR
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.
1da177e4 331 */
0d7ebbbc
DR
332#ifndef __used
333# define __used /* unimplemented */
334#endif
335
336#ifndef __maybe_unused
337# define __maybe_unused /* unimplemented */
1da177e4
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338#endif
339
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LZ
340#ifndef __always_unused
341# define __always_unused /* unimplemented */
342#endif
343
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DW
344#ifndef noinline
345#define noinline
346#endif
347
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AM
348/*
349 * Rather then using noinline to prevent stack consumption, use
e6be0c9e 350 * noinline_for_stack instead. For documentation reasons.
735c4fb9
AM
351 */
352#define noinline_for_stack noinline
353
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DW
354#ifndef __always_inline
355#define __always_inline inline
356#endif
357
358#endif /* __KERNEL__ */
359
1da177e4
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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
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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
f3fe866d
SR
387/* Simple shorthand for a section definition */
388#ifndef __section
389# define __section(S) __attribute__ ((__section__(#S)))
390#endif
391
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AK
392#ifndef __visible
393#define __visible
394#endif
395
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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
47933ad4
PZ
401/* Is this type a native word size -- useful for atomic operations */
402#ifndef __native_word
536fa402 403# define __native_word(t) (sizeof(t) == sizeof(char) || sizeof(t) == sizeof(short) || sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long))
47933ad4
PZ
404#endif
405
9f0cf4ad
AV
406/* Compile time object size, -1 for unknown */
407#ifndef __compiletime_object_size
408# define __compiletime_object_size(obj) -1
409#endif
4a312769
AV
410#ifndef __compiletime_warning
411# define __compiletime_warning(message)
412#endif
63312b6a
AV
413#ifndef __compiletime_error
414# define __compiletime_error(message)
2c0d259e
JH
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) \
9a8ab1c3 423 do { ((void)sizeof(char[1 - 2 * condition])); } while (0)
2c0d259e
JH
424# endif
425#endif
426#ifndef __compiletime_error_fallback
c361d3e5 427# define __compiletime_error_fallback(condition) do { } while (0)
63312b6a 428#endif
c361d3e5 429
9a8ab1c3
DS
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
47933ad4
PZ
454#define compiletime_assert_atomic_type(t) \
455 compiletime_assert(__native_word(t), \
456 "Need native word sized stores/loads for atomicity.")
457
9c3cdc1f
LT
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 *
927609d6
CB
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 *
663fdcbe 476 * If possible use READ_ONCE()/WRITE_ONCE() instead.
9c3cdc1f 477 */
927609d6 478#define __ACCESS_ONCE(x) ({ \
c5b19946 479 __maybe_unused typeof(x) __var = (__force typeof(x)) 0; \
927609d6
CB
480 (volatile typeof(x) *)&(x); })
481#define ACCESS_ONCE(x) (*__ACCESS_ONCE(x))
9c3cdc1f 482
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PZ
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({ \
38183b9c 493 typeof(p) _________p1 = READ_ONCE(p); \
0a04b016
PZ
494 smp_read_barrier_depends(); /* Dependency order vs. p above. */ \
495 (_________p1); \
496})
497
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MH
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")))
376e2424 501# define nokprobe_inline __always_inline
324670b6
MH
502#else
503# define __kprobes
376e2424 504# define nokprobe_inline inline
324670b6 505#endif
1da177e4 506#endif /* __LINUX_COMPILER_H */