1 /*
2 * linux/percpu-defs.h - basic definitions for percpu areas
3 *
4 * DO NOT INCLUDE DIRECTLY OUTSIDE PERCPU IMPLEMENTATION PROPER.
5 *
6 * This file is separate from linux/percpu.h to avoid cyclic inclusion
7 * dependency from arch header files. Only to be included from
8 * asm/percpu.h.
9 *
10 * This file includes macros necessary to declare percpu sections and
11 * variables, and definitions of percpu accessors and operations. It
12 * should provide enough percpu features to arch header files even when
13 * they can only include asm/percpu.h to avoid cyclic inclusion dependency.
14 */
15
16 #ifndef _LINUX_PERCPU_DEFS_H
17 #define _LINUX_PERCPU_DEFS_H
18
19 #ifdef CONFIG_SMP
20
21 #ifdef MODULE
22 #define PER_CPU_SHARED_ALIGNED_SECTION ""
23 #define PER_CPU_ALIGNED_SECTION ""
24 #else
25 #define PER_CPU_SHARED_ALIGNED_SECTION "..shared_aligned"
26 #define PER_CPU_ALIGNED_SECTION "..shared_aligned"
27 #endif
28 #define PER_CPU_FIRST_SECTION "..first"
29
30 #else
31
32 #define PER_CPU_SHARED_ALIGNED_SECTION ""
33 #define PER_CPU_ALIGNED_SECTION "..shared_aligned"
34 #define PER_CPU_FIRST_SECTION ""
35
36 #endif
37
38 #ifdef CONFIG_PAGE_TABLE_ISOLATION
39 #define USER_MAPPED_SECTION "..user_mapped"
40 #else
41 #define USER_MAPPED_SECTION ""
42 #endif
43
44 /*
45 * Base implementations of per-CPU variable declarations and definitions, where
46 * the section in which the variable is to be placed is provided by the
47 * 'sec' argument. This may be used to affect the parameters governing the
48 * variable's storage.
49 *
50 * NOTE! The sections for the DECLARE and for the DEFINE must match, lest
51 * linkage errors occur due the compiler generating the wrong code to access
52 * that section.
53 */
54 #define __PCPU_ATTRS(sec) \
55 __percpu __attribute__((section(PER_CPU_BASE_SECTION sec))) \
56 PER_CPU_ATTRIBUTES
57
58 #define __PCPU_DUMMY_ATTRS \
59 __attribute__((section(".discard"), unused))
60
61 /*
62 * s390 and alpha modules require percpu variables to be defined as
63 * weak to force the compiler to generate GOT based external
64 * references for them. This is necessary because percpu sections
65 * will be located outside of the usually addressable area.
66 *
67 * This definition puts the following two extra restrictions when
68 * defining percpu variables.
69 *
70 * 1. The symbol must be globally unique, even the static ones.
71 * 2. Static percpu variables cannot be defined inside a function.
72 *
73 * Archs which need weak percpu definitions should define
74 * ARCH_NEEDS_WEAK_PER_CPU in asm/percpu.h when necessary.
75 *
76 * To ensure that the generic code observes the above two
77 * restrictions, if CONFIG_DEBUG_FORCE_WEAK_PER_CPU is set weak
78 * definition is used for all cases.
79 */
80 #if defined(ARCH_NEEDS_WEAK_PER_CPU) || defined(CONFIG_DEBUG_FORCE_WEAK_PER_CPU)
81 /*
82 * __pcpu_scope_* dummy variable is used to enforce scope. It
83 * receives the static modifier when it's used in front of
84 * DEFINE_PER_CPU() and will trigger build failure if
85 * DECLARE_PER_CPU() is used for the same variable.
86 *
87 * __pcpu_unique_* dummy variable is used to enforce symbol uniqueness
88 * such that hidden weak symbol collision, which will cause unrelated
89 * variables to share the same address, can be detected during build.
90 */
91 #define DECLARE_PER_CPU_SECTION(type, name, sec) \
92 extern __PCPU_DUMMY_ATTRS char __pcpu_scope_##name; \
93 extern __PCPU_ATTRS(sec) __typeof__(type) name
94
95 #define DEFINE_PER_CPU_SECTION(type, name, sec) \
96 __PCPU_DUMMY_ATTRS char __pcpu_scope_##name; \
97 extern __PCPU_DUMMY_ATTRS char __pcpu_unique_##name; \
98 __PCPU_DUMMY_ATTRS char __pcpu_unique_##name; \
99 extern __PCPU_ATTRS(sec) __typeof__(type) name; \
100 __PCPU_ATTRS(sec) PER_CPU_DEF_ATTRIBUTES __weak \
101 __typeof__(type) name
102 #else
103 /*
104 * Normal declaration and definition macros.
105 */
106 #define DECLARE_PER_CPU_SECTION(type, name, sec) \
107 extern __PCPU_ATTRS(sec) __typeof__(type) name
108
109 #define DEFINE_PER_CPU_SECTION(type, name, sec) \
110 __PCPU_ATTRS(sec) PER_CPU_DEF_ATTRIBUTES \
111 __typeof__(type) name
112 #endif
113
114 /*
115 * Variant on the per-CPU variable declaration/definition theme used for
116 * ordinary per-CPU variables.
117 */
118 #define DECLARE_PER_CPU(type, name) \
119 DECLARE_PER_CPU_SECTION(type, name, "")
120
121 #define DEFINE_PER_CPU(type, name) \
122 DEFINE_PER_CPU_SECTION(type, name, "")
123
124 #define DECLARE_PER_CPU_USER_MAPPED(type, name) \
125 DECLARE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION)
126
127 #define DEFINE_PER_CPU_USER_MAPPED(type, name) \
128 DEFINE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION)
129
130 /*
131 * Declaration/definition used for per-CPU variables that must come first in
132 * the set of variables.
133 */
134 #define DECLARE_PER_CPU_FIRST(type, name) \
135 DECLARE_PER_CPU_SECTION(type, name, PER_CPU_FIRST_SECTION)
136
137 #define DEFINE_PER_CPU_FIRST(type, name) \
138 DEFINE_PER_CPU_SECTION(type, name, PER_CPU_FIRST_SECTION)
139
140 /*
141 * Declaration/definition used for per-CPU variables that must be cacheline
142 * aligned under SMP conditions so that, whilst a particular instance of the
143 * data corresponds to a particular CPU, inefficiencies due to direct access by
144 * other CPUs are reduced by preventing the data from unnecessarily spanning
145 * cachelines.
146 *
147 * An example of this would be statistical data, where each CPU's set of data
148 * is updated by that CPU alone, but the data from across all CPUs is collated
149 * by a CPU processing a read from a proc file.
150 */
151 #define DECLARE_PER_CPU_SHARED_ALIGNED(type, name) \
152 DECLARE_PER_CPU_SECTION(type, name, PER_CPU_SHARED_ALIGNED_SECTION) \
153 ____cacheline_aligned_in_smp
154
155 #define DEFINE_PER_CPU_SHARED_ALIGNED(type, name) \
156 DEFINE_PER_CPU_SECTION(type, name, PER_CPU_SHARED_ALIGNED_SECTION) \
157 ____cacheline_aligned_in_smp
158
159 #define DECLARE_PER_CPU_SHARED_ALIGNED_USER_MAPPED(type, name) \
160 DECLARE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION PER_CPU_SHARED_ALIGNED_SECTION) \
161 ____cacheline_aligned_in_smp
162
163 #define DEFINE_PER_CPU_SHARED_ALIGNED_USER_MAPPED(type, name) \
164 DEFINE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION PER_CPU_SHARED_ALIGNED_SECTION) \
165 ____cacheline_aligned_in_smp
166
167 #define DECLARE_PER_CPU_ALIGNED(type, name) \
168 DECLARE_PER_CPU_SECTION(type, name, PER_CPU_ALIGNED_SECTION) \
169 ____cacheline_aligned
170
171 #define DEFINE_PER_CPU_ALIGNED(type, name) \
172 DEFINE_PER_CPU_SECTION(type, name, PER_CPU_ALIGNED_SECTION) \
173 ____cacheline_aligned
174
175 /*
176 * Declaration/definition used for per-CPU variables that must be page aligned.
177 */
178 #define DECLARE_PER_CPU_PAGE_ALIGNED(type, name) \
179 DECLARE_PER_CPU_SECTION(type, name, "..page_aligned") \
180 __aligned(PAGE_SIZE)
181
182 #define DEFINE_PER_CPU_PAGE_ALIGNED(type, name) \
183 DEFINE_PER_CPU_SECTION(type, name, "..page_aligned") \
184 __aligned(PAGE_SIZE)
185 /*
186 * Declaration/definition used for per-CPU variables that must be page aligned and need to be mapped in user mode.
187 */
188 #define DECLARE_PER_CPU_PAGE_ALIGNED_USER_MAPPED(type, name) \
189 DECLARE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION"..page_aligned") \
190 __aligned(PAGE_SIZE)
191
192 #define DEFINE_PER_CPU_PAGE_ALIGNED_USER_MAPPED(type, name) \
193 DEFINE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION"..page_aligned") \
194 __aligned(PAGE_SIZE)
195
196 /*
197 * Declaration/definition used for per-CPU variables that must be read mostly.
198 */
199 #define DECLARE_PER_CPU_READ_MOSTLY(type, name) \
200 DECLARE_PER_CPU_SECTION(type, name, "..read_mostly")
201
202 #define DEFINE_PER_CPU_READ_MOSTLY(type, name) \
203 DEFINE_PER_CPU_SECTION(type, name, "..read_mostly")
204
205 /*
206 * Intermodule exports for per-CPU variables. sparse forgets about
207 * address space across EXPORT_SYMBOL(), change EXPORT_SYMBOL() to
208 * noop if __CHECKER__.
209 */
210 #ifndef __CHECKER__
211 #define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(var)
212 #define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(var)
213 #else
214 #define EXPORT_PER_CPU_SYMBOL(var)
215 #define EXPORT_PER_CPU_SYMBOL_GPL(var)
216 #endif
217
218 /*
219 * Accessors and operations.
220 */
221 #ifndef __ASSEMBLY__
222
223 /*
224 * __verify_pcpu_ptr() verifies @ptr is a percpu pointer without evaluating
225 * @ptr and is invoked once before a percpu area is accessed by all
226 * accessors and operations. This is performed in the generic part of
227 * percpu and arch overrides don't need to worry about it; however, if an
228 * arch wants to implement an arch-specific percpu accessor or operation,
229 * it may use __verify_pcpu_ptr() to verify the parameters.
230 *
231 * + 0 is required in order to convert the pointer type from a
232 * potential array type to a pointer to a single item of the array.
233 */
234 #define __verify_pcpu_ptr(ptr) \
235 do { \
236 const void __percpu *__vpp_verify = (typeof((ptr) + 0))NULL; \
237 (void)__vpp_verify; \
238 } while (0)
239
240 #ifdef CONFIG_SMP
241
242 /*
243 * Add an offset to a pointer but keep the pointer as-is. Use RELOC_HIDE()
244 * to prevent the compiler from making incorrect assumptions about the
245 * pointer value. The weird cast keeps both GCC and sparse happy.
246 */
247 #define SHIFT_PERCPU_PTR(__p, __offset) \
248 RELOC_HIDE((typeof(*(__p)) __kernel __force *)(__p), (__offset))
249
250 #define per_cpu_ptr(ptr, cpu) \
251 ({ \
252 __verify_pcpu_ptr(ptr); \
253 SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu))); \
254 })
255
256 #define raw_cpu_ptr(ptr) \
257 ({ \
258 __verify_pcpu_ptr(ptr); \
259 arch_raw_cpu_ptr(ptr); \
260 })
261
262 #ifdef CONFIG_DEBUG_PREEMPT
263 #define this_cpu_ptr(ptr) \
264 ({ \
265 __verify_pcpu_ptr(ptr); \
266 SHIFT_PERCPU_PTR(ptr, my_cpu_offset); \
267 })
268 #else
269 #define this_cpu_ptr(ptr) raw_cpu_ptr(ptr)
270 #endif
271
272 #else /* CONFIG_SMP */
273
274 #define VERIFY_PERCPU_PTR(__p) \
275 ({ \
276 __verify_pcpu_ptr(__p); \
277 (typeof(*(__p)) __kernel __force *)(__p); \
278 })
279
280 #define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); VERIFY_PERCPU_PTR(ptr); })
281 #define raw_cpu_ptr(ptr) per_cpu_ptr(ptr, 0)
282 #define this_cpu_ptr(ptr) raw_cpu_ptr(ptr)
283
284 #endif /* CONFIG_SMP */
285
286 #define per_cpu(var, cpu) (*per_cpu_ptr(&(var), cpu))
287
288 /*
289 * Must be an lvalue. Since @var must be a simple identifier,
290 * we force a syntax error here if it isn't.
291 */
292 #define get_cpu_var(var) \
293 (*({ \
294 preempt_disable(); \
295 this_cpu_ptr(&var); \
296 }))
297
298 /*
299 * The weird & is necessary because sparse considers (void)(var) to be
300 * a direct dereference of percpu variable (var).
301 */
302 #define put_cpu_var(var) \
303 do { \
304 (void)&(var); \
305 preempt_enable(); \
306 } while (0)
307
308 #define get_cpu_ptr(var) \
309 ({ \
310 preempt_disable(); \
311 this_cpu_ptr(var); \
312 })
313
314 #define put_cpu_ptr(var) \
315 do { \
316 (void)(var); \
317 preempt_enable(); \
318 } while (0)
319
320 /*
321 * Branching function to split up a function into a set of functions that
322 * are called for different scalar sizes of the objects handled.
323 */
324
325 extern void __bad_size_call_parameter(void);
326
327 #ifdef CONFIG_DEBUG_PREEMPT
328 extern void __this_cpu_preempt_check(const char *op);
329 #else
__this_cpu_preempt_check(const char * op)330 static inline void __this_cpu_preempt_check(const char *op) { }
331 #endif
332
333 #define __pcpu_size_call_return(stem, variable) \
334 ({ \
335 typeof(variable) pscr_ret__; \
336 __verify_pcpu_ptr(&(variable)); \
337 switch(sizeof(variable)) { \
338 case 1: pscr_ret__ = stem##1(variable); break; \
339 case 2: pscr_ret__ = stem##2(variable); break; \
340 case 4: pscr_ret__ = stem##4(variable); break; \
341 case 8: pscr_ret__ = stem##8(variable); break; \
342 default: \
343 __bad_size_call_parameter(); break; \
344 } \
345 pscr_ret__; \
346 })
347
348 #define __pcpu_size_call_return2(stem, variable, ...) \
349 ({ \
350 typeof(variable) pscr2_ret__; \
351 __verify_pcpu_ptr(&(variable)); \
352 switch(sizeof(variable)) { \
353 case 1: pscr2_ret__ = stem##1(variable, __VA_ARGS__); break; \
354 case 2: pscr2_ret__ = stem##2(variable, __VA_ARGS__); break; \
355 case 4: pscr2_ret__ = stem##4(variable, __VA_ARGS__); break; \
356 case 8: pscr2_ret__ = stem##8(variable, __VA_ARGS__); break; \
357 default: \
358 __bad_size_call_parameter(); break; \
359 } \
360 pscr2_ret__; \
361 })
362
363 /*
364 * Special handling for cmpxchg_double. cmpxchg_double is passed two
365 * percpu variables. The first has to be aligned to a double word
366 * boundary and the second has to follow directly thereafter.
367 * We enforce this on all architectures even if they don't support
368 * a double cmpxchg instruction, since it's a cheap requirement, and it
369 * avoids breaking the requirement for architectures with the instruction.
370 */
371 #define __pcpu_double_call_return_bool(stem, pcp1, pcp2, ...) \
372 ({ \
373 bool pdcrb_ret__; \
374 __verify_pcpu_ptr(&(pcp1)); \
375 BUILD_BUG_ON(sizeof(pcp1) != sizeof(pcp2)); \
376 VM_BUG_ON((unsigned long)(&(pcp1)) % (2 * sizeof(pcp1))); \
377 VM_BUG_ON((unsigned long)(&(pcp2)) != \
378 (unsigned long)(&(pcp1)) + sizeof(pcp1)); \
379 switch(sizeof(pcp1)) { \
380 case 1: pdcrb_ret__ = stem##1(pcp1, pcp2, __VA_ARGS__); break; \
381 case 2: pdcrb_ret__ = stem##2(pcp1, pcp2, __VA_ARGS__); break; \
382 case 4: pdcrb_ret__ = stem##4(pcp1, pcp2, __VA_ARGS__); break; \
383 case 8: pdcrb_ret__ = stem##8(pcp1, pcp2, __VA_ARGS__); break; \
384 default: \
385 __bad_size_call_parameter(); break; \
386 } \
387 pdcrb_ret__; \
388 })
389
390 #define __pcpu_size_call(stem, variable, ...) \
391 do { \
392 __verify_pcpu_ptr(&(variable)); \
393 switch(sizeof(variable)) { \
394 case 1: stem##1(variable, __VA_ARGS__);break; \
395 case 2: stem##2(variable, __VA_ARGS__);break; \
396 case 4: stem##4(variable, __VA_ARGS__);break; \
397 case 8: stem##8(variable, __VA_ARGS__);break; \
398 default: \
399 __bad_size_call_parameter();break; \
400 } \
401 } while (0)
402
403 /*
404 * this_cpu operations (C) 2008-2013 Christoph Lameter <cl@linux.com>
405 *
406 * Optimized manipulation for memory allocated through the per cpu
407 * allocator or for addresses of per cpu variables.
408 *
409 * These operation guarantee exclusivity of access for other operations
410 * on the *same* processor. The assumption is that per cpu data is only
411 * accessed by a single processor instance (the current one).
412 *
413 * The arch code can provide optimized implementation by defining macros
414 * for certain scalar sizes. F.e. provide this_cpu_add_2() to provide per
415 * cpu atomic operations for 2 byte sized RMW actions. If arch code does
416 * not provide operations for a scalar size then the fallback in the
417 * generic code will be used.
418 *
419 * cmpxchg_double replaces two adjacent scalars at once. The first two
420 * parameters are per cpu variables which have to be of the same size. A
421 * truth value is returned to indicate success or failure (since a double
422 * register result is difficult to handle). There is very limited hardware
423 * support for these operations, so only certain sizes may work.
424 */
425
426 /*
427 * Operations for contexts where we do not want to do any checks for
428 * preemptions. Unless strictly necessary, always use [__]this_cpu_*()
429 * instead.
430 *
431 * If there is no other protection through preempt disable and/or disabling
432 * interupts then one of these RMW operations can show unexpected behavior
433 * because the execution thread was rescheduled on another processor or an
434 * interrupt occurred and the same percpu variable was modified from the
435 * interrupt context.
436 */
437 #define raw_cpu_read(pcp) __pcpu_size_call_return(raw_cpu_read_, pcp)
438 #define raw_cpu_write(pcp, val) __pcpu_size_call(raw_cpu_write_, pcp, val)
439 #define raw_cpu_add(pcp, val) __pcpu_size_call(raw_cpu_add_, pcp, val)
440 #define raw_cpu_and(pcp, val) __pcpu_size_call(raw_cpu_and_, pcp, val)
441 #define raw_cpu_or(pcp, val) __pcpu_size_call(raw_cpu_or_, pcp, val)
442 #define raw_cpu_add_return(pcp, val) __pcpu_size_call_return2(raw_cpu_add_return_, pcp, val)
443 #define raw_cpu_xchg(pcp, nval) __pcpu_size_call_return2(raw_cpu_xchg_, pcp, nval)
444 #define raw_cpu_cmpxchg(pcp, oval, nval) \
445 __pcpu_size_call_return2(raw_cpu_cmpxchg_, pcp, oval, nval)
446 #define raw_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) \
447 __pcpu_double_call_return_bool(raw_cpu_cmpxchg_double_, pcp1, pcp2, oval1, oval2, nval1, nval2)
448
449 #define raw_cpu_sub(pcp, val) raw_cpu_add(pcp, -(val))
450 #define raw_cpu_inc(pcp) raw_cpu_add(pcp, 1)
451 #define raw_cpu_dec(pcp) raw_cpu_sub(pcp, 1)
452 #define raw_cpu_sub_return(pcp, val) raw_cpu_add_return(pcp, -(typeof(pcp))(val))
453 #define raw_cpu_inc_return(pcp) raw_cpu_add_return(pcp, 1)
454 #define raw_cpu_dec_return(pcp) raw_cpu_add_return(pcp, -1)
455
456 /*
457 * Operations for contexts that are safe from preemption/interrupts. These
458 * operations verify that preemption is disabled.
459 */
460 #define __this_cpu_read(pcp) \
461 ({ \
462 __this_cpu_preempt_check("read"); \
463 raw_cpu_read(pcp); \
464 })
465
466 #define __this_cpu_write(pcp, val) \
467 ({ \
468 __this_cpu_preempt_check("write"); \
469 raw_cpu_write(pcp, val); \
470 })
471
472 #define __this_cpu_add(pcp, val) \
473 ({ \
474 __this_cpu_preempt_check("add"); \
475 raw_cpu_add(pcp, val); \
476 })
477
478 #define __this_cpu_and(pcp, val) \
479 ({ \
480 __this_cpu_preempt_check("and"); \
481 raw_cpu_and(pcp, val); \
482 })
483
484 #define __this_cpu_or(pcp, val) \
485 ({ \
486 __this_cpu_preempt_check("or"); \
487 raw_cpu_or(pcp, val); \
488 })
489
490 #define __this_cpu_add_return(pcp, val) \
491 ({ \
492 __this_cpu_preempt_check("add_return"); \
493 raw_cpu_add_return(pcp, val); \
494 })
495
496 #define __this_cpu_xchg(pcp, nval) \
497 ({ \
498 __this_cpu_preempt_check("xchg"); \
499 raw_cpu_xchg(pcp, nval); \
500 })
501
502 #define __this_cpu_cmpxchg(pcp, oval, nval) \
503 ({ \
504 __this_cpu_preempt_check("cmpxchg"); \
505 raw_cpu_cmpxchg(pcp, oval, nval); \
506 })
507
508 #define __this_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) \
509 ({ __this_cpu_preempt_check("cmpxchg_double"); \
510 raw_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2); \
511 })
512
513 #define __this_cpu_sub(pcp, val) __this_cpu_add(pcp, -(typeof(pcp))(val))
514 #define __this_cpu_inc(pcp) __this_cpu_add(pcp, 1)
515 #define __this_cpu_dec(pcp) __this_cpu_sub(pcp, 1)
516 #define __this_cpu_sub_return(pcp, val) __this_cpu_add_return(pcp, -(typeof(pcp))(val))
517 #define __this_cpu_inc_return(pcp) __this_cpu_add_return(pcp, 1)
518 #define __this_cpu_dec_return(pcp) __this_cpu_add_return(pcp, -1)
519
520 /*
521 * Operations with implied preemption/interrupt protection. These
522 * operations can be used without worrying about preemption or interrupt.
523 */
524 #define this_cpu_read(pcp) __pcpu_size_call_return(this_cpu_read_, pcp)
525 #define this_cpu_write(pcp, val) __pcpu_size_call(this_cpu_write_, pcp, val)
526 #define this_cpu_add(pcp, val) __pcpu_size_call(this_cpu_add_, pcp, val)
527 #define this_cpu_and(pcp, val) __pcpu_size_call(this_cpu_and_, pcp, val)
528 #define this_cpu_or(pcp, val) __pcpu_size_call(this_cpu_or_, pcp, val)
529 #define this_cpu_add_return(pcp, val) __pcpu_size_call_return2(this_cpu_add_return_, pcp, val)
530 #define this_cpu_xchg(pcp, nval) __pcpu_size_call_return2(this_cpu_xchg_, pcp, nval)
531 #define this_cpu_cmpxchg(pcp, oval, nval) \
532 __pcpu_size_call_return2(this_cpu_cmpxchg_, pcp, oval, nval)
533 #define this_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) \
534 __pcpu_double_call_return_bool(this_cpu_cmpxchg_double_, pcp1, pcp2, oval1, oval2, nval1, nval2)
535
536 #define this_cpu_sub(pcp, val) this_cpu_add(pcp, -(typeof(pcp))(val))
537 #define this_cpu_inc(pcp) this_cpu_add(pcp, 1)
538 #define this_cpu_dec(pcp) this_cpu_sub(pcp, 1)
539 #define this_cpu_sub_return(pcp, val) this_cpu_add_return(pcp, -(typeof(pcp))(val))
540 #define this_cpu_inc_return(pcp) this_cpu_add_return(pcp, 1)
541 #define this_cpu_dec_return(pcp) this_cpu_add_return(pcp, -1)
542
543 #endif /* __ASSEMBLY__ */
544 #endif /* _LINUX_PERCPU_DEFS_H */
545