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1 office 1 From 9b2c282b348dfe966bbba967dc7a45ce817cce50 Mon Sep 17 00:00:00 2001
2 From: Tom Rini <trini@konsulko.com>
3 Date: Mon, 29 Feb 2016 11:34:15 -0500
4 Subject: [PATCH] compiler*.h: sync include/linux/compiler*.h with Linux
5 4.5-rc6
6  
7 Copy these from Linux v4.5-rc6 tag.
8  
9 This is needed so that we can keep up with newer gcc versions. Note
10 that we don't have the uapi/ hierarchy from the kernel so continue to
11 use <linux/types.h>
12  
13 Signed-off-by: Tom Rini <trini@konsulko.com>
14 ---
15 include/linux/compiler-gcc.h | 266 ++++++++++++++++++++++++++++++++++------
16 include/linux/compiler-gcc3.h | 21 ----
17 include/linux/compiler-gcc4.h | 63 ----------
18 include/linux/compiler-intel.h | 45 +++++++
19 include/linux/compiler.h | 270 +++++++++++++++++++++++++++++++++++++++--
20 5 files changed, 534 insertions(+), 131 deletions(-)
21 delete mode 100644 include/linux/compiler-gcc3.h
22 delete mode 100644 include/linux/compiler-gcc4.h
23 create mode 100644 include/linux/compiler-intel.h
24  
25 diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
26 index 9896e54..22ab246 100644
27 --- a/include/linux/compiler-gcc.h
28 +++ b/include/linux/compiler-gcc.h
29 @@ -5,11 +5,28 @@
30 /*
31 * Common definitions for all gcc versions go here.
32 */
33 -
34 +#define GCC_VERSION (__GNUC__ * 10000 \
35 + + __GNUC_MINOR__ * 100 \
36 + + __GNUC_PATCHLEVEL__)
37  
38 /* Optimization barrier */
39 +
40 /* The "volatile" is due to gcc bugs */
41 #define barrier() __asm__ __volatile__("": : :"memory")
42 +/*
43 + * This version is i.e. to prevent dead stores elimination on @ptr
44 + * where gcc and llvm may behave differently when otherwise using
45 + * normal barrier(): while gcc behavior gets along with a normal
46 + * barrier(), llvm needs an explicit input variable to be assumed
47 + * clobbered. The issue is as follows: while the inline asm might
48 + * access any memory it wants, the compiler could have fit all of
49 + * @ptr into memory registers instead, and since @ptr never escaped
50 + * from that, it proofed that the inline asm wasn't touching any of
51 + * it. This version works well with both compilers, i.e. we're telling
52 + * the compiler that the inline asm absolutely may see the contents
53 + * of @ptr. See also: https://llvm.org/bugs/show_bug.cgi?id=15495
54 + */
55 +#define barrier_data(ptr) __asm__ __volatile__("": :"r"(ptr) :"memory")
56  
57 /*
58 * This macro obfuscates arithmetic on a variable address so that gcc
59 @@ -29,41 +46,63 @@
60 * the inline assembly constraint from =g to =r, in this particular
61 * case either is valid.
62 */
63 -#define RELOC_HIDE(ptr, off) \
64 - ({ unsigned long __ptr; \
65 - __asm__ ("" : "=r"(__ptr) : "0"(ptr)); \
66 - (typeof(ptr)) (__ptr + (off)); })
67 +#define RELOC_HIDE(ptr, off) \
68 +({ \
69 + unsigned long __ptr; \
70 + __asm__ ("" : "=r"(__ptr) : "0"(ptr)); \
71 + (typeof(ptr)) (__ptr + (off)); \
72 +})
73 +
74 +/* Make the optimizer believe the variable can be manipulated arbitrarily. */
75 +#define OPTIMIZER_HIDE_VAR(var) \
76 + __asm__ ("" : "=r" (var) : "0" (var))
77  
78 +#ifdef __CHECKER__
79 +#define __must_be_array(a) 0
80 +#else
81 /* &a[0] degrades to a pointer: a different type from an array */
82 -#define __must_be_array(a) \
83 - BUILD_BUG_ON_ZERO(__builtin_types_compatible_p(typeof(a), typeof(&a[0])))
84 +#define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
85 +#endif
86  
87 /*
88 * Force always-inline if the user requests it so via the .config,
89 * or if gcc is too old:
90 */
91 -#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \
92 +#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \
93 !defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4)
94 -# define inline inline __attribute__((always_inline))
95 -# define __inline__ __inline__ __attribute__((always_inline))
96 -# define __inline __inline __attribute__((always_inline))
97 +#define inline inline __attribute__((always_inline)) notrace
98 +#define __inline__ __inline__ __attribute__((always_inline)) notrace
99 +#define __inline __inline __attribute__((always_inline)) notrace
100 +#else
101 +/* A lot of inline functions can cause havoc with function tracing */
102 +#define inline inline notrace
103 +#define __inline__ __inline__ notrace
104 +#define __inline __inline notrace
105 #endif
106  
107 -#define __deprecated __attribute__((deprecated))
108 -#ifndef __packed
109 -# define __packed __attribute__((packed))
110 -#endif
111 -#define __weak __attribute__((weak))
112 +#define __always_inline inline __attribute__((always_inline))
113 +#define noinline __attribute__((noinline))
114 +
115 +#define __deprecated __attribute__((deprecated))
116 +#define __packed __attribute__((packed))
117 +#define __weak __attribute__((weak))
118 +#define __alias(symbol) __attribute__((alias(#symbol)))
119  
120 /*
121 - * it doesn't make sense on ARM (currently the only user of __naked) to trace
122 - * naked functions because then mcount is called without stack and frame pointer
123 - * being set up and there is no chance to restore the lr register to the value
124 - * before mcount was called.
125 + * it doesn't make sense on ARM (currently the only user of __naked)
126 + * to trace naked functions because then mcount is called without
127 + * stack and frame pointer being set up and there is no chance to
128 + * restore the lr register to the value before mcount was called.
129 + *
130 + * The asm() bodies of naked functions often depend on standard calling
131 + * conventions, therefore they must be noinline and noclone.
132 + *
133 + * GCC 4.[56] currently fail to enforce this, so we must do so ourselves.
134 + * See GCC PR44290.
135 */
136 -#define __naked __attribute__((naked)) notrace
137 +#define __naked __attribute__((naked)) noinline __noclone notrace
138  
139 -#define __noreturn __attribute__((noreturn))
140 +#define __noreturn __attribute__((noreturn))
141  
142 /*
143 * From the GCC manual:
144 @@ -75,19 +114,170 @@
145 * would be.
146 * [...]
147 */
148 -#ifndef __pure
149 -# define __pure __attribute__((pure))
150 -#endif
151 -#ifndef __aligned
152 -# define __aligned(x) __attribute__((aligned(x)))
153 -#endif
154 -#define __printf(a,b) __attribute__((format(printf,a,b)))
155 -#define noinline __attribute__((noinline))
156 -#define __attribute_const__ __attribute__((__const__))
157 -#define __maybe_unused __attribute__((unused))
158 -#define __always_unused __attribute__((unused))
159 -
160 -#define __gcc_header(x) #x
161 -#define _gcc_header(x) __gcc_header(linux/compiler-gcc##x.h)
162 -#define gcc_header(x) _gcc_header(x)
163 -#include gcc_header(__GNUC__)
164 +#define __pure __attribute__((pure))
165 +#define __aligned(x) __attribute__((aligned(x)))
166 +#define __printf(a, b) __attribute__((format(printf, a, b)))
167 +#define __scanf(a, b) __attribute__((format(scanf, a, b)))
168 +#define __attribute_const__ __attribute__((__const__))
169 +#define __maybe_unused __attribute__((unused))
170 +#define __always_unused __attribute__((unused))
171 +
172 +/* gcc version specific checks */
173 +
174 +#if GCC_VERSION < 30200
175 +# error Sorry, your compiler is too old - please upgrade it.
176 +#endif
177 +
178 +#if GCC_VERSION < 30300
179 +# define __used __attribute__((__unused__))
180 +#else
181 +# define __used __attribute__((__used__))
182 +#endif
183 +
184 +#ifdef CONFIG_GCOV_KERNEL
185 +# if GCC_VERSION < 30400
186 +# error "GCOV profiling support for gcc versions below 3.4 not included"
187 +# endif /* __GNUC_MINOR__ */
188 +#endif /* CONFIG_GCOV_KERNEL */
189 +
190 +#if GCC_VERSION >= 30400
191 +#define __must_check __attribute__((warn_unused_result))
192 +#endif
193 +
194 +#if GCC_VERSION >= 40000
195 +
196 +/* GCC 4.1.[01] miscompiles __weak */
197 +#ifdef __KERNEL__
198 +# if GCC_VERSION >= 40100 && GCC_VERSION <= 40101
199 +# error Your version of gcc miscompiles the __weak directive
200 +# endif
201 +#endif
202 +
203 +#define __used __attribute__((__used__))
204 +#define __compiler_offsetof(a, b) \
205 + __builtin_offsetof(a, b)
206 +
207 +#if GCC_VERSION >= 40100 && GCC_VERSION < 40600
208 +# define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
209 +#endif
210 +
211 +#if GCC_VERSION >= 40300
212 +/* Mark functions as cold. gcc will assume any path leading to a call
213 + * to them will be unlikely. This means a lot of manual unlikely()s
214 + * are unnecessary now for any paths leading to the usual suspects
215 + * like BUG(), printk(), panic() etc. [but let's keep them for now for
216 + * older compilers]
217 + *
218 + * Early snapshots of gcc 4.3 don't support this and we can't detect this
219 + * in the preprocessor, but we can live with this because they're unreleased.
220 + * Maketime probing would be overkill here.
221 + *
222 + * gcc also has a __attribute__((__hot__)) to move hot functions into
223 + * a special section, but I don't see any sense in this right now in
224 + * the kernel context
225 + */
226 +#define __cold __attribute__((__cold__))
227 +
228 +#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
229 +
230 +#ifndef __CHECKER__
231 +# define __compiletime_warning(message) __attribute__((warning(message)))
232 +# define __compiletime_error(message) __attribute__((error(message)))
233 +#endif /* __CHECKER__ */
234 +#endif /* GCC_VERSION >= 40300 */
235 +
236 +#if GCC_VERSION >= 40500
237 +/*
238 + * Mark a position in code as unreachable. This can be used to
239 + * suppress control flow warnings after asm blocks that transfer
240 + * control elsewhere.
241 + *
242 + * Early snapshots of gcc 4.5 don't support this and we can't detect
243 + * this in the preprocessor, but we can live with this because they're
244 + * unreleased. Really, we need to have autoconf for the kernel.
245 + */
246 +#define unreachable() __builtin_unreachable()
247 +
248 +/* Mark a function definition as prohibited from being cloned. */
249 +#define __noclone __attribute__((__noclone__))
250 +
251 +#endif /* GCC_VERSION >= 40500 */
252 +
253 +#if GCC_VERSION >= 40600
254 +/*
255 + * When used with Link Time Optimization, gcc can optimize away C functions or
256 + * variables which are referenced only from assembly code. __visible tells the
257 + * optimizer that something else uses this function or variable, thus preventing
258 + * this.
259 + */
260 +#define __visible __attribute__((externally_visible))
261 +#endif
262 +
263 +
264 +#if GCC_VERSION >= 40900 && !defined(__CHECKER__)
265 +/*
266 + * __assume_aligned(n, k): Tell the optimizer that the returned
267 + * pointer can be assumed to be k modulo n. The second argument is
268 + * optional (default 0), so we use a variadic macro to make the
269 + * shorthand.
270 + *
271 + * Beware: Do not apply this to functions which may return
272 + * ERR_PTRs. Also, it is probably unwise to apply it to functions
273 + * returning extra information in the low bits (but in that case the
274 + * compiler should see some alignment anyway, when the return value is
275 + * massaged by 'flags = ptr & 3; ptr &= ~3;').
276 + */
277 +#define __assume_aligned(a, ...) __attribute__((__assume_aligned__(a, ## __VA_ARGS__)))
278 +#endif
279 +
280 +/*
281 + * GCC 'asm goto' miscompiles certain code sequences:
282 + *
283 + * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
284 + *
285 + * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
286 + *
287 + * (asm goto is automatically volatile - the naming reflects this.)
288 + */
289 +#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
290 +
291 +#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP
292 +#if GCC_VERSION >= 40400
293 +#define __HAVE_BUILTIN_BSWAP32__
294 +#define __HAVE_BUILTIN_BSWAP64__
295 +#endif
296 +#if GCC_VERSION >= 40800 || (defined(__powerpc__) && GCC_VERSION >= 40600)
297 +#define __HAVE_BUILTIN_BSWAP16__
298 +#endif
299 +#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */
300 +
301 +#if GCC_VERSION >= 50000
302 +#define KASAN_ABI_VERSION 4
303 +#elif GCC_VERSION >= 40902
304 +#define KASAN_ABI_VERSION 3
305 +#endif
306 +
307 +#if GCC_VERSION >= 40902
308 +/*
309 + * Tell the compiler that address safety instrumentation (KASAN)
310 + * should not be applied to that function.
311 + * Conflicts with inlining: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368
312 + */
313 +#define __no_sanitize_address __attribute__((no_sanitize_address))
314 +#endif
315 +
316 +#endif /* gcc version >= 40000 specific checks */
317 +
318 +#if !defined(__noclone)
319 +#define __noclone /* not needed */
320 +#endif
321 +
322 +#if !defined(__no_sanitize_address)
323 +#define __no_sanitize_address
324 +#endif
325 +
326 +/*
327 + * A trick to suppress uninitialized variable warning without generating any
328 + * code
329 + */
330 +#define uninitialized_var(x) x = x
331 diff --git a/include/linux/compiler-gcc3.h b/include/linux/compiler-gcc3.h
332 deleted file mode 100644
333 index 2befe65..0000000
334 --- a/include/linux/compiler-gcc3.h
335 +++ /dev/null
336 @@ -1,21 +0,0 @@
337 -#ifndef __LINUX_COMPILER_H
338 -#error "Please don't include <linux/compiler-gcc3.h> directly, include <linux/compiler.h> instead."
339 -#endif
340 -
341 -#if __GNUC_MINOR__ >= 3
342 -# define __used __attribute__((__used__))
343 -#else
344 -# define __used __attribute__((__unused__))
345 -#endif
346 -
347 -#if __GNUC_MINOR__ >= 4
348 -#define __must_check __attribute__((warn_unused_result))
349 -#endif
350 -
351 -/*
352 - * A trick to suppress uninitialized variable warning without generating any
353 - * code
354 - */
355 -#define uninitialized_var(x) x = x
356 -
357 -#define __always_inline inline __attribute__((always_inline))
358 diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h
359 deleted file mode 100644
360 index 27d11ca..0000000
361 --- a/include/linux/compiler-gcc4.h
362 +++ /dev/null
363 @@ -1,63 +0,0 @@
364 -#ifndef __LINUX_COMPILER_H
365 -#error "Please don't include <linux/compiler-gcc4.h> directly, include <linux/compiler.h> instead."
366 -#endif
367 -
368 -/* GCC 4.1.[01] miscompiles __weak */
369 -#ifdef __KERNEL__
370 -# if __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ <= 1
371 -# error Your version of gcc miscompiles the __weak directive
372 -# endif
373 -#endif
374 -
375 -#define __used __attribute__((__used__))
376 -#define __must_check __attribute__((warn_unused_result))
377 -#define __compiler_offsetof(a,b) __builtin_offsetof(a,b)
378 -#ifndef __always_inline
379 -# define __always_inline inline __attribute__((always_inline))
380 -#endif
381 -
382 -/*
383 - * A trick to suppress uninitialized variable warning without generating any
384 - * code
385 - */
386 -#define uninitialized_var(x) x = x
387 -
388 -#if __GNUC_MINOR__ >= 3
389 -/* Mark functions as cold. gcc will assume any path leading to a call
390 - to them will be unlikely. This means a lot of manual unlikely()s
391 - are unnecessary now for any paths leading to the usual suspects
392 - like BUG(), printk(), panic() etc. [but let's keep them for now for
393 - older compilers]
394 -
395 - Early snapshots of gcc 4.3 don't support this and we can't detect this
396 - in the preprocessor, but we can live with this because they're unreleased.
397 - Maketime probing would be overkill here.
398 -
399 - gcc also has a __attribute__((__hot__)) to move hot functions into
400 - a special section, but I don't see any sense in this right now in
401 - the kernel context */
402 -#define __cold __attribute__((__cold__))
403 -
404 -
405 -#if __GNUC_MINOR__ >= 5
406 -/*
407 - * Mark a position in code as unreachable. This can be used to
408 - * suppress control flow warnings after asm blocks that transfer
409 - * control elsewhere.
410 - *
411 - * Early snapshots of gcc 4.5 don't support this and we can't detect
412 - * this in the preprocessor, but we can live with this because they're
413 - * unreleased. Really, we need to have autoconf for the kernel.
414 - */
415 -#define unreachable() __builtin_unreachable()
416 -#endif
417 -
418 -#endif
419 -
420 -#if __GNUC_MINOR__ > 0
421 -#define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
422 -#endif
423 -#if __GNUC_MINOR__ >= 4
424 -#define __compiletime_warning(message) __attribute__((warning(message)))
425 -#define __compiletime_error(message) __attribute__((error(message)))
426 -#endif
427 diff --git a/include/linux/compiler-intel.h b/include/linux/compiler-intel.h
428 new file mode 100644
429 index 0000000..d4c7113
430 --- /dev/null
431 +++ b/include/linux/compiler-intel.h
432 @@ -0,0 +1,45 @@
433 +#ifndef __LINUX_COMPILER_H
434 +#error "Please don't include <linux/compiler-intel.h> directly, include <linux/compiler.h> instead."
435 +#endif
436 +
437 +#ifdef __ECC
438 +
439 +/* Some compiler specific definitions are overwritten here
440 + * for Intel ECC compiler
441 + */
442 +
443 +#include <asm/intrinsics.h>
444 +
445 +/* Intel ECC compiler doesn't support gcc specific asm stmts.
446 + * It uses intrinsics to do the equivalent things.
447 + */
448 +#undef barrier
449 +#undef barrier_data
450 +#undef RELOC_HIDE
451 +#undef OPTIMIZER_HIDE_VAR
452 +
453 +#define barrier() __memory_barrier()
454 +#define barrier_data(ptr) barrier()
455 +
456 +#define RELOC_HIDE(ptr, off) \
457 + ({ unsigned long __ptr; \
458 + __ptr = (unsigned long) (ptr); \
459 + (typeof(ptr)) (__ptr + (off)); })
460 +
461 +/* This should act as an optimization barrier on var.
462 + * Given that this compiler does not have inline assembly, a compiler barrier
463 + * is the best we can do.
464 + */
465 +#define OPTIMIZER_HIDE_VAR(var) barrier()
466 +
467 +/* Intel ECC compiler doesn't support __builtin_types_compatible_p() */
468 +#define __must_be_array(a) 0
469 +
470 +#endif
471 +
472 +#ifndef __HAVE_BUILTIN_BSWAP16__
473 +/* icc has this, but it's called _bswap16 */
474 +#define __HAVE_BUILTIN_BSWAP16__
475 +#define __builtin_bswap16 _bswap16
476 +#endif
477 +
478 diff --git a/include/linux/compiler.h b/include/linux/compiler.h
479 index 5be3dab..020ad16 100644
480 --- a/include/linux/compiler.h
481 +++ b/include/linux/compiler.h
482 @@ -5,16 +5,24 @@
483  
484 #ifdef __CHECKER__
485 # define __user __attribute__((noderef, address_space(1)))
486 -# define __kernel /* default address space */
487 +# define __kernel __attribute__((address_space(0)))
488 # define __safe __attribute__((safe))
489 # define __force __attribute__((force))
490 # define __nocast __attribute__((nocast))
491 # define __iomem __attribute__((noderef, address_space(2)))
492 +# define __must_hold(x) __attribute__((context(x,1,1)))
493 # define __acquires(x) __attribute__((context(x,0,1)))
494 # define __releases(x) __attribute__((context(x,1,0)))
495 # define __acquire(x) __context__(x,1)
496 # define __release(x) __context__(x,-1)
497 # define __cond_lock(x,c) ((c) ? ({ __acquire(x); 1; }) : 0)
498 +# define __percpu __attribute__((noderef, address_space(3)))
499 +# define __pmem __attribute__((noderef, address_space(5)))
500 +#ifdef CONFIG_SPARSE_RCU_POINTER
501 +# define __rcu __attribute__((noderef, address_space(4)))
502 +#else
503 +# define __rcu
504 +#endif
505 extern void __chk_user_ptr(const volatile void __user *);
506 extern void __chk_io_ptr(const volatile void __iomem *);
507 #else
508 @@ -27,20 +35,32 @@ extern void __chk_io_ptr(const volatile void __iomem *);
509 # define __chk_user_ptr(x) (void)0
510 # define __chk_io_ptr(x) (void)0
511 # define __builtin_warning(x, y...) (1)
512 +# define __must_hold(x)
513 # define __acquires(x)
514 # define __releases(x)
515 # define __acquire(x) (void)0
516 # define __release(x) (void)0
517 # define __cond_lock(x,c) (c)
518 +# define __percpu
519 +# define __rcu
520 +# define __pmem
521 #endif
522  
523 +/* Indirect macros required for expanded argument pasting, eg. __LINE__. */
524 +#define ___PASTE(a,b) a##b
525 +#define __PASTE(a,b) ___PASTE(a,b)
526 +
527 #ifdef __KERNEL__
528  
529 #ifdef __GNUC__
530 #include <linux/compiler-gcc.h>
531 #endif
532  
533 +#if defined(CC_USING_HOTPATCH) && !defined(__CHECKER__)
534 +#define notrace __attribute__((hotpatch(0,0)))
535 +#else
536 #define notrace __attribute__((no_instrument_function))
537 +#endif
538  
539 /* Intel compiler defines __GNUC__. So we will overwrite implementations
540 * coming from above header files here
541 @@ -49,6 +69,13 @@ extern void __chk_io_ptr(const volatile void __iomem *);
542 # include <linux/compiler-intel.h>
543 #endif
544  
545 +/* Clang compiler defines __GNUC__. So we will overwrite implementations
546 + * coming from above header files here
547 + */
548 +#ifdef __clang__
549 +#include <linux/compiler-clang.h>
550 +#endif
551 +
552 /*
553 * Generic compiler-dependent macros required for kernel
554 * build go below this comment. Actual compiler/compiler version
555 @@ -117,7 +144,7 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
556 */
557 #define if(cond, ...) __trace_if( (cond , ## __VA_ARGS__) )
558 #define __trace_if(cond) \
559 - if (__builtin_constant_p((cond)) ? !!(cond) : \
560 + if (__builtin_constant_p(!!(cond)) ? !!(cond) : \
561 ({ \
562 int ______r; \
563 static struct ftrace_branch_data \
564 @@ -144,6 +171,10 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
565 # define barrier() __memory_barrier()
566 #endif
567  
568 +#ifndef barrier_data
569 +# define barrier_data(ptr) barrier()
570 +#endif
571 +
572 /* Unreachable code */
573 #ifndef unreachable
574 # define unreachable() do { } while (1)
575 @@ -156,6 +187,135 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
576 (typeof(ptr)) (__ptr + (off)); })
577 #endif
578  
579 +#ifndef OPTIMIZER_HIDE_VAR
580 +#define OPTIMIZER_HIDE_VAR(var) barrier()
581 +#endif
582 +
583 +/* Not-quite-unique ID. */
584 +#ifndef __UNIQUE_ID
585 +# define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __LINE__)
586 +#endif
587 +
588 +#include <linux/types.h>
589 +
590 +#define __READ_ONCE_SIZE \
591 +({ \
592 + switch (size) { \
593 + case 1: *(__u8 *)res = *(volatile __u8 *)p; break; \
594 + case 2: *(__u16 *)res = *(volatile __u16 *)p; break; \
595 + case 4: *(__u32 *)res = *(volatile __u32 *)p; break; \
596 + case 8: *(__u64 *)res = *(volatile __u64 *)p; break; \
597 + default: \
598 + barrier(); \
599 + __builtin_memcpy((void *)res, (const void *)p, size); \
600 + barrier(); \
601 + } \
602 +})
603 +
604 +static __always_inline
605 +void __read_once_size(const volatile void *p, void *res, int size)
606 +{
607 + __READ_ONCE_SIZE;
608 +}
609 +
610 +#ifdef CONFIG_KASAN
611 +/*
612 + * This function is not 'inline' because __no_sanitize_address confilcts
613 + * with inlining. Attempt to inline it may cause a build failure.
614 + * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368
615 + * '__maybe_unused' allows us to avoid defined-but-not-used warnings.
616 + */
617 +static __no_sanitize_address __maybe_unused
618 +void __read_once_size_nocheck(const volatile void *p, void *res, int size)
619 +{
620 + __READ_ONCE_SIZE;
621 +}
622 +#else
623 +static __always_inline
624 +void __read_once_size_nocheck(const volatile void *p, void *res, int size)
625 +{
626 + __READ_ONCE_SIZE;
627 +}
628 +#endif
629 +
630 +static __always_inline void __write_once_size(volatile void *p, void *res, int size)
631 +{
632 + switch (size) {
633 + case 1: *(volatile __u8 *)p = *(__u8 *)res; break;
634 + case 2: *(volatile __u16 *)p = *(__u16 *)res; break;
635 + case 4: *(volatile __u32 *)p = *(__u32 *)res; break;
636 + case 8: *(volatile __u64 *)p = *(__u64 *)res; break;
637 + default:
638 + barrier();
639 + __builtin_memcpy((void *)p, (const void *)res, size);
640 + barrier();
641 + }
642 +}
643 +
644 +/*
645 + * Prevent the compiler from merging or refetching reads or writes. The
646 + * compiler is also forbidden from reordering successive instances of
647 + * READ_ONCE, WRITE_ONCE and ACCESS_ONCE (see below), but only when the
648 + * compiler is aware of some particular ordering. One way to make the
649 + * compiler aware of ordering is to put the two invocations of READ_ONCE,
650 + * WRITE_ONCE or ACCESS_ONCE() in different C statements.
651 + *
652 + * In contrast to ACCESS_ONCE these two macros will also work on aggregate
653 + * data types like structs or unions. If the size of the accessed data
654 + * type exceeds the word size of the machine (e.g., 32 bits or 64 bits)
655 + * READ_ONCE() and WRITE_ONCE() will fall back to memcpy and print a
656 + * compile-time warning.
657 + *
658 + * Their two major use cases are: (1) Mediating communication between
659 + * process-level code and irq/NMI handlers, all running on the same CPU,
660 + * and (2) Ensuring that the compiler does not fold, spindle, or otherwise
661 + * mutilate accesses that either do not require ordering or that interact
662 + * with an explicit memory barrier or atomic instruction that provides the
663 + * required ordering.
664 + */
665 +
666 +#define __READ_ONCE(x, check) \
667 +({ \
668 + union { typeof(x) __val; char __c[1]; } __u; \
669 + if (check) \
670 + __read_once_size(&(x), __u.__c, sizeof(x)); \
671 + else \
672 + __read_once_size_nocheck(&(x), __u.__c, sizeof(x)); \
673 + __u.__val; \
674 +})
675 +#define READ_ONCE(x) __READ_ONCE(x, 1)
676 +
677 +/*
678 + * Use READ_ONCE_NOCHECK() instead of READ_ONCE() if you need
679 + * to hide memory access from KASAN.
680 + */
681 +#define READ_ONCE_NOCHECK(x) __READ_ONCE(x, 0)
682 +
683 +#define WRITE_ONCE(x, val) \
684 +({ \
685 + union { typeof(x) __val; char __c[1]; } __u = \
686 + { .__val = (__force typeof(x)) (val) }; \
687 + __write_once_size(&(x), __u.__c, sizeof(x)); \
688 + __u.__val; \
689 +})
690 +
691 +/**
692 + * smp_cond_acquire() - Spin wait for cond with ACQUIRE ordering
693 + * @cond: boolean expression to wait for
694 + *
695 + * Equivalent to using smp_load_acquire() on the condition variable but employs
696 + * the control dependency of the wait to reduce the barrier on many platforms.
697 + *
698 + * The control dependency provides a LOAD->STORE order, the additional RMB
699 + * provides LOAD->LOAD order, together they provide LOAD->{LOAD,STORE} order,
700 + * aka. ACQUIRE.
701 + */
702 +#define smp_cond_acquire(cond) do { \
703 + while (!(cond)) \
704 + cpu_relax(); \
705 + smp_rmb(); /* ctrl + rmb := acquire */ \
706 +} while (0)
707 +
708 #endif /* __KERNEL__ */
709  
710 #endif /* __ASSEMBLY__ */
711 @@ -228,7 +388,7 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
712  
713 /*
714 * Rather then using noinline to prevent stack consumption, use
715 - * noinline_for_stack instead. For documentaiton reasons.
716 + * noinline_for_stack instead. For documentation reasons.
717 */
718 #define noinline_for_stack noinline
719  
720 @@ -270,11 +430,28 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
721 # define __section(S) __attribute__ ((__section__(#S)))
722 #endif
723  
724 +#ifndef __visible
725 +#define __visible
726 +#endif
727 +
728 +/*
729 + * Assume alignment of return value.
730 + */
731 +#ifndef __assume_aligned
732 +#define __assume_aligned(a, ...)
733 +#endif
734 +
735 +
736 /* Are two types/vars the same type (ignoring qualifiers)? */
737 #ifndef __same_type
738 # define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
739 #endif
740  
741 +/* Is this type a native word size -- useful for atomic operations */
742 +#ifndef __native_word
743 +# define __native_word(t) (sizeof(t) == sizeof(char) || sizeof(t) == sizeof(short) || sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long))
744 +#endif
745 +
746 /* Compile time object size, -1 for unknown */
747 #ifndef __compiletime_object_size
748 # define __compiletime_object_size(obj) -1
749 @@ -284,7 +461,48 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
750 #endif
751 #ifndef __compiletime_error
752 # define __compiletime_error(message)
753 +/*
754 + * Sparse complains of variable sized arrays due to the temporary variable in
755 + * __compiletime_assert. Unfortunately we can't just expand it out to make
756 + * sparse see a constant array size without breaking compiletime_assert on old
757 + * versions of GCC (e.g. 4.2.4), so hide the array from sparse altogether.
758 + */
759 +# ifndef __CHECKER__
760 +# define __compiletime_error_fallback(condition) \
761 + do { ((void)sizeof(char[1 - 2 * condition])); } while (0)
762 +# endif
763 #endif
764 +#ifndef __compiletime_error_fallback
765 +# define __compiletime_error_fallback(condition) do { } while (0)
766 +#endif
767 +
768 +#define __compiletime_assert(condition, msg, prefix, suffix) \
769 + do { \
770 + bool __cond = !(condition); \
771 + extern void prefix ## suffix(void) __compiletime_error(msg); \
772 + if (__cond) \
773 + prefix ## suffix(); \
774 + __compiletime_error_fallback(__cond); \
775 + } while (0)
776 +
777 +#define _compiletime_assert(condition, msg, prefix, suffix) \
778 + __compiletime_assert(condition, msg, prefix, suffix)
779 +
780 +/**
781 + * compiletime_assert - break build and emit msg if condition is false
782 + * @condition: a compile-time constant condition to check
783 + * @msg: a message to emit if condition is false
784 + *
785 + * In tradition of POSIX assert, this macro will break the build if the
786 + * supplied condition is *false*, emitting the supplied error message if the
787 + * compiler has support to do so.
788 + */
789 +#define compiletime_assert(condition, msg) \
790 + _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
791 +
792 +#define compiletime_assert_atomic_type(t) \
793 + compiletime_assert(__native_word(t), \
794 + "Need native word sized stores/loads for atomicity.")
795  
796 /*
797 * Prevent the compiler from merging or refetching accesses. The compiler
798 @@ -293,11 +511,45 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
799 * to make the compiler aware of ordering is to put the two invocations of
800 * ACCESS_ONCE() in different C statements.
801 *
802 - * This macro does absolutely -nothing- to prevent the CPU from reordering,
803 - * merging, or refetching absolutely anything at any time. Its main intended
804 - * use is to mediate communication between process-level code and irq/NMI
805 - * handlers, all running on the same CPU.
806 + * ACCESS_ONCE will only work on scalar types. For union types, ACCESS_ONCE
807 + * on a union member will work as long as the size of the member matches the
808 + * size of the union and the size is smaller than word size.
809 + *
810 + * The major use cases of ACCESS_ONCE used to be (1) Mediating communication
811 + * between process-level code and irq/NMI handlers, all running on the same CPU,
812 + * and (2) Ensuring that the compiler does not fold, spindle, or otherwise
813 + * mutilate accesses that either do not require ordering or that interact
814 + * with an explicit memory barrier or atomic instruction that provides the
815 + * required ordering.
816 + *
817 + * If possible use READ_ONCE()/WRITE_ONCE() instead.
818 */
819 -#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
820 -
821 +#define __ACCESS_ONCE(x) ({ \
822 + __maybe_unused typeof(x) __var = (__force typeof(x)) 0; \
823 + (volatile typeof(x) *)&(x); })
824 +#define ACCESS_ONCE(x) (*__ACCESS_ONCE(x))
825 +
826 +/**
827 + * lockless_dereference() - safely load a pointer for later dereference
828 + * @p: The pointer to load
829 + *
830 + * Similar to rcu_dereference(), but for situations where the pointed-to
831 + * object's lifetime is managed by something other than RCU. That
832 + * "something other" might be reference counting or simple immortality.
833 + */
834 +#define lockless_dereference(p) \
835 +({ \
836 + typeof(p) _________p1 = READ_ONCE(p); \
837 + smp_read_barrier_depends(); /* Dependency order vs. p above. */ \
838 + (_________p1); \
839 +})
840 +
841 +/* Ignore/forbid kprobes attach on very low level functions marked by this attribute: */
842 +#ifdef CONFIG_KPROBES
843 +# define __kprobes __attribute__((__section__(".kprobes.text")))
844 +# define nokprobe_inline __always_inline
845 +#else
846 +# define __kprobes
847 +# define nokprobe_inline inline
848 +#endif
849 #endif /* __LINUX_COMPILER_H */
850 --
851 2.7.4
852