include/linux/percpu-defs.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * linux/percpu-defs.h - basic definitions for percpu areas
   4  *
   5  * DO NOT INCLUDE DIRECTLY OUTSIDE PERCPU IMPLEMENTATION PROPER.
   6  *
   7  * This file is separate from linux/percpu.h to avoid cyclic inclusion
   8  * dependency from arch header files.  Only to be included from
   9  * asm/percpu.h.
  10  *
  11  * This file includes macros necessary to declare percpu sections and
  12  * variables, and definitions of percpu accessors and operations.  It
  13  * should provide enough percpu features to arch header files even when
  14  * they can only include asm/percpu.h to avoid cyclic inclusion dependency.
  15  */
  16
  17 #ifndef _LINUX_PERCPU_DEFS_H
  18 #define _LINUX_PERCPU_DEFS_H
  19
  20 #ifdef CONFIG_SMP
  21
  22 #ifdef MODULE
  23 #define PER_CPU_SHARED_ALIGNED_SECTION ""
  24 #define PER_CPU_ALIGNED_SECTION ""
  25 #else
  26 #define PER_CPU_SHARED_ALIGNED_SECTION "..shared_aligned"
  27 #define PER_CPU_ALIGNED_SECTION "..shared_aligned"
  28 #endif
  29 #define PER_CPU_FIRST_SECTION "..first"
  30
  31 #else
  32
  33 #define PER_CPU_SHARED_ALIGNED_SECTION ""
  34 #define PER_CPU_ALIGNED_SECTION "..shared_aligned"
  35 #define PER_CPU_FIRST_SECTION ""
  36
  37 #endif
  38
  39 /*
  40  * Base implementations of per-CPU variable declarations and definitions, where
  41  * the section in which the variable is to be placed is provided by the
  42  * 'sec' argument.  This may be used to affect the parameters governing the
  43  * variable's storage.
  44  *
  45  * NOTE!  The sections for the DECLARE and for the DEFINE must match, lest
  46  * linkage errors occur due the compiler generating the wrong code to access
  47  * that section.
  48  */
  49 #define __PCPU_ATTRS(sec)                                               \
  50         __percpu __attribute__((section(PER_CPU_BASE_SECTION sec)))     \
  51         PER_CPU_ATTRIBUTES
  52
  53 #define __PCPU_DUMMY_ATTRS                                              \
  54         __section(".discard") __attribute__((unused))
  55
  56 /*
  57  * s390 and alpha modules require percpu variables to be defined as
  58  * weak to force the compiler to generate GOT based external
  59  * references for them.  This is necessary because percpu sections
  60  * will be located outside of the usually addressable area.
  61  *
  62  * This definition puts the following two extra restrictions when
  63  * defining percpu variables.
  64  *
  65  * 1. The symbol must be globally unique, even the static ones.
  66  * 2. Static percpu variables cannot be defined inside a function.
  67  *
  68  * Archs which need weak percpu definitions should define
  69  * ARCH_NEEDS_WEAK_PER_CPU in asm/percpu.h when necessary.
  70  *
  71  * To ensure that the generic code observes the above two
  72  * restrictions, if CONFIG_DEBUG_FORCE_WEAK_PER_CPU is set weak
  73  * definition is used for all cases.
  74  */
  75 #if defined(ARCH_NEEDS_WEAK_PER_CPU) || defined(CONFIG_DEBUG_FORCE_WEAK_PER_CPU)
  76 /*
  77  * __pcpu_scope_* dummy variable is used to enforce scope.  It
  78  * receives the static modifier when it's used in front of
  79  * DEFINE_PER_CPU() and will trigger build failure if
  80  * DECLARE_PER_CPU() is used for the same variable.
  81  *
  82  * __pcpu_unique_* dummy variable is used to enforce symbol uniqueness
  83  * such that hidden weak symbol collision, which will cause unrelated
  84  * variables to share the same address, can be detected during build.
  85  */
  86 #define DECLARE_PER_CPU_SECTION(type, name, sec)                        \
  87         extern __PCPU_DUMMY_ATTRS char __pcpu_scope_##name;             \
  88         extern __PCPU_ATTRS(sec) __typeof__(type) name
  89
  90 #define DEFINE_PER_CPU_SECTION(type, name, sec)                         \
  91         __PCPU_DUMMY_ATTRS char __pcpu_scope_##name;                    \
  92         extern __PCPU_DUMMY_ATTRS char __pcpu_unique_##name;            \
  93         __PCPU_DUMMY_ATTRS char __pcpu_unique_##name;                   \
  94         extern __PCPU_ATTRS(sec) __typeof__(type) name;                 \
  95         __PCPU_ATTRS(sec) __weak __typeof__(type) name
  96 #else
  97 /*
  98  * Normal declaration and definition macros.
  99  */
 100 #define DECLARE_PER_CPU_SECTION(type, name, sec)                        \
 101         extern __PCPU_ATTRS(sec) __typeof__(type) name
 102
 103 #define DEFINE_PER_CPU_SECTION(type, name, sec)                         \
 104         __PCPU_ATTRS(sec) __typeof__(type) name
 105 #endif
 106
 107 /*
 108  * Variant on the per-CPU variable declaration/definition theme used for
 109  * ordinary per-CPU variables.
 110  */
 111 #define DECLARE_PER_CPU(type, name)                                     \
 112         DECLARE_PER_CPU_SECTION(type, name, "")
 113
 114 #define DEFINE_PER_CPU(type, name)                                      \
 115         DEFINE_PER_CPU_SECTION(type, name, "")
 116
 117 /*
 118  * Declaration/definition used for per-CPU variables that must come first in
 119  * the set of variables.
 120  */
 121 #define DECLARE_PER_CPU_FIRST(type, name)                               \
 122         DECLARE_PER_CPU_SECTION(type, name, PER_CPU_FIRST_SECTION)
 123
 124 #define DEFINE_PER_CPU_FIRST(type, name)                                \
 125         DEFINE_PER_CPU_SECTION(type, name, PER_CPU_FIRST_SECTION)
 126
 127 /*
 128  * Declaration/definition used for per-CPU variables that must be cacheline
 129  * aligned under SMP conditions so that, whilst a particular instance of the
 130  * data corresponds to a particular CPU, inefficiencies due to direct access by
 131  * other CPUs are reduced by preventing the data from unnecessarily spanning
 132  * cachelines.
 133  *
 134  * An example of this would be statistical data, where each CPU's set of data
 135  * is updated by that CPU alone, but the data from across all CPUs is collated
 136  * by a CPU processing a read from a proc file.
 137  */
 138 #define DECLARE_PER_CPU_SHARED_ALIGNED(type, name)                      \
 139         DECLARE_PER_CPU_SECTION(type, name, PER_CPU_SHARED_ALIGNED_SECTION) \
 140         ____cacheline_aligned_in_smp
 141
 142 #define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)                       \
 143         DEFINE_PER_CPU_SECTION(type, name, PER_CPU_SHARED_ALIGNED_SECTION) \
 144         ____cacheline_aligned_in_smp
 145
 146 #define DECLARE_PER_CPU_ALIGNED(type, name)                             \
 147         DECLARE_PER_CPU_SECTION(type, name, PER_CPU_ALIGNED_SECTION)    \
 148         ____cacheline_aligned
 149
 150 #define DEFINE_PER_CPU_ALIGNED(type, name)                              \
 151         DEFINE_PER_CPU_SECTION(type, name, PER_CPU_ALIGNED_SECTION)     \
 152         ____cacheline_aligned
 153
 154 /*
 155  * Declaration/definition used for per-CPU variables that must be page aligned.
 156  */
 157 #define DECLARE_PER_CPU_PAGE_ALIGNED(type, name)                        \
 158         DECLARE_PER_CPU_SECTION(type, name, "..page_aligned")           \
 159         __aligned(PAGE_SIZE)
 160
 161 #define DEFINE_PER_CPU_PAGE_ALIGNED(type, name)                         \
 162         DEFINE_PER_CPU_SECTION(type, name, "..page_aligned")            \
 163         __aligned(PAGE_SIZE)
 164
 165 /*
 166  * Declaration/definition used for per-CPU variables that must be read mostly.
 167  */
 168 #define DECLARE_PER_CPU_READ_MOSTLY(type, name)                 \
 169         DECLARE_PER_CPU_SECTION(type, name, "..read_mostly")
 170
 171 #define DEFINE_PER_CPU_READ_MOSTLY(type, name)                          \
 172         DEFINE_PER_CPU_SECTION(type, name, "..read_mostly")
 173
 174 /*
 175  * Declaration/definition used for per-CPU variables that should be accessed
 176  * as decrypted when memory encryption is enabled in the guest.
 177  */
 178 #ifdef CONFIG_AMD_MEM_ENCRYPT
 179 #define DECLARE_PER_CPU_DECRYPTED(type, name)                           \
 180         DECLARE_PER_CPU_SECTION(type, name, "..decrypted")
 181
 182 #define DEFINE_PER_CPU_DECRYPTED(type, name)                            \
 183         DEFINE_PER_CPU_SECTION(type, name, "..decrypted")
 184 #else
 185 #define DEFINE_PER_CPU_DECRYPTED(type, name)    DEFINE_PER_CPU(type, name)
 186 #endif
 187
 188 /*
 189  * Intermodule exports for per-CPU variables.  sparse forgets about
 190  * address space across EXPORT_SYMBOL(), change EXPORT_SYMBOL() to
 191  * noop if __CHECKER__.
 192  */
 193 #ifndef __CHECKER__
 194 #define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(var)
 195 #define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(var)
 196 #else
 197 #define EXPORT_PER_CPU_SYMBOL(var)
 198 #define EXPORT_PER_CPU_SYMBOL_GPL(var)
 199 #endif
 200
 201 /*
 202  * Accessors and operations.
 203  */
 204 #ifndef __ASSEMBLY__
 205
 206 /*
 207  * __verify_pcpu_ptr() verifies @ptr is a percpu pointer without evaluating
 208  * @ptr and is invoked once before a percpu area is accessed by all
 209  * accessors and operations.  This is performed in the generic part of
 210  * percpu and arch overrides don't need to worry about it; however, if an
 211  * arch wants to implement an arch-specific percpu accessor or operation,
 212  * it may use __verify_pcpu_ptr() to verify the parameters.
 213  *
 214  * + 0 is required in order to convert the pointer type from a
 215  * potential array type to a pointer to a single item of the array.
 216  */
 217 #define __verify_pcpu_ptr(ptr)                                          \
 218 do {                                                                    \
 219         const void __percpu *__vpp_verify = (typeof((ptr) + 0))NULL;    \
 220         (void)__vpp_verify;                                             \
 221 } while (0)
 222
 223 #define PERCPU_PTR(__p)                                                 \
 224         (typeof(*(__p)) __force __kernel *)((__force unsigned long)(__p))
 225
 226 #ifdef CONFIG_SMP
 227
 228 /*
 229  * Add an offset to a pointer.  Use RELOC_HIDE() to prevent the compiler
 230  * from making incorrect assumptions about the pointer value.
 231  */
 232 #define SHIFT_PERCPU_PTR(__p, __offset)                                 \
 233         RELOC_HIDE(PERCPU_PTR(__p), (__offset))
 234
 235 #define per_cpu_ptr(ptr, cpu)                                           \
 236 ({                                                                      \
 237         __verify_pcpu_ptr(ptr);                                         \
 238         SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu)));                 \
 239 })
 240
 241 #define raw_cpu_ptr(ptr)                                                \
 242 ({                                                                      \
 243         __verify_pcpu_ptr(ptr);                                         \
 244         arch_raw_cpu_ptr(ptr);                                          \
 245 })
 246
 247 #ifdef CONFIG_DEBUG_PREEMPT
 248 #define this_cpu_ptr(ptr)                                               \
 249 ({                                                                      \
 250         __verify_pcpu_ptr(ptr);                                         \
 251         SHIFT_PERCPU_PTR(ptr, my_cpu_offset);                           \
 252 })
 253 #else
 254 #define this_cpu_ptr(ptr) raw_cpu_ptr(ptr)
 255 #endif
 256
 257 #else   /* CONFIG_SMP */
 258
 259 #define per_cpu_ptr(ptr, cpu)                                           \
 260 ({                                                                      \
 261         (void)(cpu);                                                    \
 262         __verify_pcpu_ptr(ptr);                                         \
 263         PERCPU_PTR(ptr);                                                \
 264 })
 265
 266 #define raw_cpu_ptr(ptr)        per_cpu_ptr(ptr, 0)
 267 #define this_cpu_ptr(ptr)       raw_cpu_ptr(ptr)
 268
 269 #endif  /* CONFIG_SMP */
 270
 271 #define per_cpu(var, cpu)       (*per_cpu_ptr(&(var), cpu))
 272
 273 /*
 274  * Must be an lvalue. Since @var must be a simple identifier,
 275  * we force a syntax error here if it isn't.
 276  */
 277 #define get_cpu_var(var)                                                \
 278 (*({                                                                    \
 279         preempt_disable();                                              \
 280         this_cpu_ptr(&var);                                             \
 281 }))
 282
 283 /*
 284  * The weird & is necessary because sparse considers (void)(var) to be
 285  * a direct dereference of percpu variable (var).
 286  */
 287 #define put_cpu_var(var)                                                \
 288 do {                                                                    \
 289         (void)&(var);                                                   \
 290         preempt_enable();                                               \
 291 } while (0)
 292
 293 #define get_cpu_ptr(var)                                                \
 294 ({                                                                      \
 295         preempt_disable();                                              \
 296         this_cpu_ptr(var);                                              \
 297 })
 298
 299 #define put_cpu_ptr(var)                                                \
 300 do {                                                                    \
 301         (void)(var);                                                    \
 302         preempt_enable();                                               \
 303 } while (0)
 304
 305 /*
 306  * Branching function to split up a function into a set of functions that
 307  * are called for different scalar sizes of the objects handled.
 308  */
 309
 310 extern void __bad_size_call_parameter(void);
 311
 312 #ifdef CONFIG_DEBUG_PREEMPT
 313 extern void __this_cpu_preempt_check(const char *op);
 314 #else
 315 static __always_inline void __this_cpu_preempt_check(const char *op) { }
 316 #endif
 317
 318 #define __pcpu_size_call_return(stem, variable)                         \
 319 ({                                                                      \
 320         typeof(variable) pscr_ret__;                                    \
 321         __verify_pcpu_ptr(&(variable));                                 \
 322         switch(sizeof(variable)) {                                      \
 323         case 1: pscr_ret__ = stem##1(variable); break;                  \
 324         case 2: pscr_ret__ = stem##2(variable); break;                  \
 325         case 4: pscr_ret__ = stem##4(variable); break;                  \
 326         case 8: pscr_ret__ = stem##8(variable); break;                  \
 327         default:                                                        \
 328                 __bad_size_call_parameter(); break;                     \
 329         }                                                               \
 330         pscr_ret__;                                                     \
 331 })
 332
 333 #define __pcpu_size_call_return2(stem, variable, ...)                   \
 334 ({                                                                      \
 335         typeof(variable) pscr2_ret__;                                   \
 336         __verify_pcpu_ptr(&(variable));                                 \
 337         switch(sizeof(variable)) {                                      \
 338         case 1: pscr2_ret__ = stem##1(variable, __VA_ARGS__); break;    \
 339         case 2: pscr2_ret__ = stem##2(variable, __VA_ARGS__); break;    \
 340         case 4: pscr2_ret__ = stem##4(variable, __VA_ARGS__); break;    \
 341         case 8: pscr2_ret__ = stem##8(variable, __VA_ARGS__); break;    \
 342         default:                                                        \
 343                 __bad_size_call_parameter(); break;                     \
 344         }                                                               \
 345         pscr2_ret__;                                                    \
 346 })
 347
 348 #define __pcpu_size_call_return2bool(stem, variable, ...)               \
 349 ({                                                                      \
 350         bool 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 #define __pcpu_size_call(stem, variable, ...)                           \
 364 do {                                                                    \
 365         __verify_pcpu_ptr(&(variable));                                 \
 366         switch(sizeof(variable)) {                                      \
 367                 case 1: stem##1(variable, __VA_ARGS__);break;           \
 368                 case 2: stem##2(variable, __VA_ARGS__);break;           \
 369                 case 4: stem##4(variable, __VA_ARGS__);break;           \
 370                 case 8: stem##8(variable, __VA_ARGS__);break;           \
 371                 default:                                                \
 372                         __bad_size_call_parameter();break;              \
 373         }                                                               \
 374 } while (0)
 375
 376 /*
 377  * this_cpu operations (C) 2008-2013 Christoph Lameter <[email protected]>
 378  *
 379  * Optimized manipulation for memory allocated through the per cpu
 380  * allocator or for addresses of per cpu variables.
 381  *
 382  * These operation guarantee exclusivity of access for other operations
 383  * on the *same* processor. The assumption is that per cpu data is only
 384  * accessed by a single processor instance (the current one).
 385  *
 386  * The arch code can provide optimized implementation by defining macros
 387  * for certain scalar sizes. F.e. provide this_cpu_add_2() to provide per
 388  * cpu atomic operations for 2 byte sized RMW actions. If arch code does
 389  * not provide operations for a scalar size then the fallback in the
 390  * generic code will be used.
 391  *
 392  * cmpxchg_double replaces two adjacent scalars at once.  The first two
 393  * parameters are per cpu variables which have to be of the same size.  A
 394  * truth value is returned to indicate success or failure (since a double
 395  * register result is difficult to handle).  There is very limited hardware
 396  * support for these operations, so only certain sizes may work.
 397  */
 398
 399 /*
 400  * Operations for contexts where we do not want to do any checks for
 401  * preemptions.  Unless strictly necessary, always use [__]this_cpu_*()
 402  * instead.
 403  *
 404  * If there is no other protection through preempt disable and/or disabling
 405  * interrupts then one of these RMW operations can show unexpected behavior
 406  * because the execution thread was rescheduled on another processor or an
 407  * interrupt occurred and the same percpu variable was modified from the
 408  * interrupt context.
 409  */
 410 #define raw_cpu_read(pcp)               __pcpu_size_call_return(raw_cpu_read_, pcp)
 411 #define raw_cpu_write(pcp, val)         __pcpu_size_call(raw_cpu_write_, pcp, val)
 412 #define raw_cpu_add(pcp, val)           __pcpu_size_call(raw_cpu_add_, pcp, val)
 413 #define raw_cpu_and(pcp, val)           __pcpu_size_call(raw_cpu_and_, pcp, val)
 414 #define raw_cpu_or(pcp, val)            __pcpu_size_call(raw_cpu_or_, pcp, val)
 415 #define raw_cpu_add_return(pcp, val)    __pcpu_size_call_return2(raw_cpu_add_return_, pcp, val)
 416 #define raw_cpu_xchg(pcp, nval)         __pcpu_size_call_return2(raw_cpu_xchg_, pcp, nval)
 417 #define raw_cpu_cmpxchg(pcp, oval, nval) \
 418         __pcpu_size_call_return2(raw_cpu_cmpxchg_, pcp, oval, nval)
 419 #define raw_cpu_try_cmpxchg(pcp, ovalp, nval) \
 420         __pcpu_size_call_return2bool(raw_cpu_try_cmpxchg_, pcp, ovalp, nval)
 421 #define raw_cpu_sub(pcp, val)           raw_cpu_add(pcp, -(val))
 422 #define raw_cpu_inc(pcp)                raw_cpu_add(pcp, 1)
 423 #define raw_cpu_dec(pcp)                raw_cpu_sub(pcp, 1)
 424 #define raw_cpu_sub_return(pcp, val)    raw_cpu_add_return(pcp, -(typeof(pcp))(val))
 425 #define raw_cpu_inc_return(pcp)         raw_cpu_add_return(pcp, 1)
 426 #define raw_cpu_dec_return(pcp)         raw_cpu_add_return(pcp, -1)
 427
 428 /*
 429  * Operations for contexts that are safe from preemption/interrupts.  These
 430  * operations verify that preemption is disabled.
 431  */
 432 #define __this_cpu_read(pcp)                                            \
 433 ({                                                                      \
 434         __this_cpu_preempt_check("read");                               \
 435         raw_cpu_read(pcp);                                              \
 436 })
 437
 438 #define __this_cpu_write(pcp, val)                                      \
 439 ({                                                                      \
 440         __this_cpu_preempt_check("write");                              \
 441         raw_cpu_write(pcp, val);                                        \
 442 })
 443
 444 #define __this_cpu_add(pcp, val)                                        \
 445 ({                                                                      \
 446         __this_cpu_preempt_check("add");                                \
 447         raw_cpu_add(pcp, val);                                          \
 448 })
 449
 450 #define __this_cpu_and(pcp, val)                                        \
 451 ({                                                                      \
 452         __this_cpu_preempt_check("and");                                \
 453         raw_cpu_and(pcp, val);                                          \
 454 })
 455
 456 #define __this_cpu_or(pcp, val)                                         \
 457 ({                                                                      \
 458         __this_cpu_preempt_check("or");                                 \
 459         raw_cpu_or(pcp, val);                                           \
 460 })
 461
 462 #define __this_cpu_add_return(pcp, val)                                 \
 463 ({                                                                      \
 464         __this_cpu_preempt_check("add_return");                         \
 465         raw_cpu_add_return(pcp, val);                                   \
 466 })
 467
 468 #define __this_cpu_xchg(pcp, nval)                                      \
 469 ({                                                                      \
 470         __this_cpu_preempt_check("xchg");                               \
 471         raw_cpu_xchg(pcp, nval);                                        \
 472 })
 473
 474 #define __this_cpu_cmpxchg(pcp, oval, nval)                             \
 475 ({                                                                      \
 476         __this_cpu_preempt_check("cmpxchg");                            \
 477         raw_cpu_cmpxchg(pcp, oval, nval);                               \
 478 })
 479
 480 #define __this_cpu_try_cmpxchg(pcp, ovalp, nval)                        \
 481 ({                                                                      \
 482         __this_cpu_preempt_check("try_cmpxchg");                        \
 483         raw_cpu_try_cmpxchg(pcp, ovalp, nval);                          \
 484 })
 485
 486 #define __this_cpu_sub(pcp, val)        __this_cpu_add(pcp, -(typeof(pcp))(val))
 487 #define __this_cpu_inc(pcp)             __this_cpu_add(pcp, 1)
 488 #define __this_cpu_dec(pcp)             __this_cpu_sub(pcp, 1)
 489 #define __this_cpu_sub_return(pcp, val) __this_cpu_add_return(pcp, -(typeof(pcp))(val))
 490 #define __this_cpu_inc_return(pcp)      __this_cpu_add_return(pcp, 1)
 491 #define __this_cpu_dec_return(pcp)      __this_cpu_add_return(pcp, -1)
 492
 493 /*
 494  * Operations with implied preemption/interrupt protection.  These
 495  * operations can be used without worrying about preemption or interrupt.
 496  */
 497 #define this_cpu_read(pcp)              __pcpu_size_call_return(this_cpu_read_, pcp)
 498 #define this_cpu_write(pcp, val)        __pcpu_size_call(this_cpu_write_, pcp, val)
 499 #define this_cpu_add(pcp, val)          __pcpu_size_call(this_cpu_add_, pcp, val)
 500 #define this_cpu_and(pcp, val)          __pcpu_size_call(this_cpu_and_, pcp, val)
 501 #define this_cpu_or(pcp, val)           __pcpu_size_call(this_cpu_or_, pcp, val)
 502 #define this_cpu_add_return(pcp, val)   __pcpu_size_call_return2(this_cpu_add_return_, pcp, val)
 503 #define this_cpu_xchg(pcp, nval)        __pcpu_size_call_return2(this_cpu_xchg_, pcp, nval)
 504 #define this_cpu_cmpxchg(pcp, oval, nval) \
 505         __pcpu_size_call_return2(this_cpu_cmpxchg_, pcp, oval, nval)
 506 #define this_cpu_try_cmpxchg(pcp, ovalp, nval) \
 507         __pcpu_size_call_return2bool(this_cpu_try_cmpxchg_, pcp, ovalp, nval)
 508 #define this_cpu_sub(pcp, val)          this_cpu_add(pcp, -(typeof(pcp))(val))
 509 #define this_cpu_inc(pcp)               this_cpu_add(pcp, 1)
 510 #define this_cpu_dec(pcp)               this_cpu_sub(pcp, 1)
 511 #define this_cpu_sub_return(pcp, val)   this_cpu_add_return(pcp, -(typeof(pcp))(val))
 512 #define this_cpu_inc_return(pcp)        this_cpu_add_return(pcp, 1)
 513 #define this_cpu_dec_return(pcp)        this_cpu_add_return(pcp, -1)
 514
 515 #endif /* __ASSEMBLY__ */
 516 #endif /* _LINUX_PERCPU_DEFS_H */