include/linux/percpu-defs.h

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