LXR linux/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) PER_CPU_DEF_ATTRIBUTES __weak                 \
  95        __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) PER_CPU_DEF_ATTRIBUTES                        \
 105        __typeof__(type) name
 106#endif
 107
 108/*
 109 * Variant on the per-CPU variable declaration/definition theme used for
 110 * ordinary per-CPU variables.
 111 */
 112#define DECLARE_PER_CPU(type, name)                                     \
 113        DECLARE_PER_CPU_SECTION(type, name, "")
 114
 115#define DEFINE_PER_CPU(type, name)                                      \
 116        DEFINE_PER_CPU_SECTION(type, name, "")
 117
 118/*
 119 * Declaration/definition used for per-CPU variables that must come first in
 120 * the set of variables.
 121 */
 122#define DECLARE_PER_CPU_FIRST(type, name)                               \
 123        DECLARE_PER_CPU_SECTION(type, name, PER_CPU_FIRST_SECTION)
 124
 125#define DEFINE_PER_CPU_FIRST(type, name)                                \
 126        DEFINE_PER_CPU_SECTION(type, name, PER_CPU_FIRST_SECTION)
 127
 128/*
 129 * Declaration/definition used for per-CPU variables that must be cacheline
 130 * aligned under SMP conditions so that, whilst a particular instance of the
 131 * data corresponds to a particular CPU, inefficiencies due to direct access by
 132 * other CPUs are reduced by preventing the data from unnecessarily spanning
 133 * cachelines.
 134 *
 135 * An example of this would be statistical data, where each CPU's set of data
 136 * is updated by that CPU alone, but the data from across all CPUs is collated
 137 * by a CPU processing a read from a proc file.
 138 */
 139#define DECLARE_PER_CPU_SHARED_ALIGNED(type, name)                      \
 140        DECLARE_PER_CPU_SECTION(type, name, PER_CPU_SHARED_ALIGNED_SECTION) \
 141        ____cacheline_aligned_in_smp
 142
 143#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)                       \
 144        DEFINE_PER_CPU_SECTION(type, name, PER_CPU_SHARED_ALIGNED_SECTION) \
 145        ____cacheline_aligned_in_smp
 146
 147#define DECLARE_PER_CPU_ALIGNED(type, name)                             \
 148        DECLARE_PER_CPU_SECTION(type, name, PER_CPU_ALIGNED_SECTION)    \
 149        ____cacheline_aligned
 150
 151#define DEFINE_PER_CPU_ALIGNED(type, name)                              \
 152        DEFINE_PER_CPU_SECTION(type, name, PER_CPU_ALIGNED_SECTION)     \
 153        ____cacheline_aligned
 154
 155/*
 156 * Declaration/definition used for per-CPU variables that must be page aligned.
 157 */
 158#define DECLARE_PER_CPU_PAGE_ALIGNED(type, name)                        \
 159        DECLARE_PER_CPU_SECTION(type, name, "..page_aligned")           \
 160        __aligned(PAGE_SIZE)
 161
 162#define DEFINE_PER_CPU_PAGE_ALIGNED(type, name)                         \
 163        DEFINE_PER_CPU_SECTION(type, name, "..page_aligned")            \
 164        __aligned(PAGE_SIZE)
 165
 166/*
 167 * Declaration/definition used for per-CPU variables that must be read mostly.
 168 */
 169#define DECLARE_PER_CPU_READ_MOSTLY(type, name)                 \
 170        DECLARE_PER_CPU_SECTION(type, name, "..read_mostly")
 171
 172#define DEFINE_PER_CPU_READ_MOSTLY(type, name)                          \
 173        DEFINE_PER_CPU_SECTION(type, name, "..read_mostly")
 174
 175/*
 176 * Intermodule exports for per-CPU variables.  sparse forgets about
 177 * address space across EXPORT_SYMBOL(), change EXPORT_SYMBOL() to
 178 * noop if __CHECKER__.
 179 */
 180#ifndef __CHECKER__
 181#define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(var)
 182#define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(var)
 183#else
 184#define EXPORT_PER_CPU_SYMBOL(var)
 185#define EXPORT_PER_CPU_SYMBOL_GPL(var)
 186#endif
 187
 188/*
 189 * Accessors and operations.
 190 */
 191#ifndef __ASSEMBLY__
 192
 193/*
 194 * __verify_pcpu_ptr() verifies @ptr is a percpu pointer without evaluating
 195 * @ptr and is invoked once before a percpu area is accessed by all
 196 * accessors and operations.  This is performed in the generic part of
 197 * percpu and arch overrides don't need to worry about it; however, if an
 198 * arch wants to implement an arch-specific percpu accessor or operation,
 199 * it may use __verify_pcpu_ptr() to verify the parameters.
 200 *
 201 * + 0 is required in order to convert the pointer type from a
 202 * potential array type to a pointer to a single item of the array.
 203 */
 204#define __verify_pcpu_ptr(ptr)                                          \
 205do {                                                                    \
 206        const void __percpu *__vpp_verify = (typeof((ptr) + 0))NULL;    \
 207        (void)__vpp_verify;                                             \
 208} while (0)
 209
 210#ifdef CONFIG_SMP
 211
 212/*
 213 * Add an offset to a pointer but keep the pointer as-is.  Use RELOC_HIDE()
 214 * to prevent the compiler from making incorrect assumptions about the
 215 * pointer value.  The weird cast keeps both GCC and sparse happy.
 216 */
 217#define SHIFT_PERCPU_PTR(__p, __offset)                                 \
 218        RELOC_HIDE((typeof(*(__p)) __kernel __force *)(__p), (__offset))
 219
 220#define per_cpu_ptr(ptr, cpu)                                           \
 221({                                                                      \
 222        __verify_pcpu_ptr(ptr);                                         \
 223        SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu)));                 \
 224})
 225
 226#define raw_cpu_ptr(ptr)                                                \
 227({                                                                      \
 228        __verify_pcpu_ptr(ptr);                                         \
 229        arch_raw_cpu_ptr(ptr);                                          \
 230})
 231
 232#ifdef CONFIG_DEBUG_PREEMPT
 233#define this_cpu_ptr(ptr)                                               \
 234({                                                                      \
 235        __verify_pcpu_ptr(ptr);                                         \
 236        SHIFT_PERCPU_PTR(ptr, my_cpu_offset);                           \
 237})
 238#else
 239#define this_cpu_ptr(ptr) raw_cpu_ptr(ptr)
 240#endif
 241
 242#else   /* CONFIG_SMP */
 243
 244#define VERIFY_PERCPU_PTR(__p)                                          \
 245({                                                                      \
 246        __verify_pcpu_ptr(__p);                                         \
 247        (typeof(*(__p)) __kernel __force *)(__p);                       \
 248})
 249
 250#define per_cpu_ptr(ptr, cpu)   ({ (void)(cpu); VERIFY_PERCPU_PTR(ptr); })
 251#define raw_cpu_ptr(ptr)        per_cpu_ptr(ptr, 0)
 252#define this_cpu_ptr(ptr)       raw_cpu_ptr(ptr)
 253
 254#endif  /* CONFIG_SMP */
 255
 256#define per_cpu(var, cpu)       (*per_cpu_ptr(&(var), cpu))
 257
 258/*
 259 * Must be an lvalue. Since @var must be a simple identifier,
 260 * we force a syntax error here if it isn't.
 261 */
 262#define get_cpu_var(var)                                                \
 263(*({                                                                    \
 264        preempt_disable();                                              \
 265        this_cpu_ptr(&var);                                             \
 266}))
 267
 268/*
 269 * The weird & is necessary because sparse considers (void)(var) to be
 270 * a direct dereference of percpu variable (var).
 271 */
 272#define put_cpu_var(var)                                                \
 273do {                                                                    \
 274        (void)&(var);                                                   \
 275        preempt_enable();                                               \
 276} while (0)
 277
 278#define get_cpu_ptr(var)                                                \
 279({                                                                      \
 280        preempt_disable();                                              \
 281        this_cpu_ptr(var);                                              \
 282})
 283
 284#define put_cpu_ptr(var)                                                \
 285do {                                                                    \
 286        (void)(var);                                                    \
 287        preempt_enable();                                               \
 288} while (0)
 289
 290/*
 291 * Branching function to split up a function into a set of functions that
 292 * are called for different scalar sizes of the objects handled.
 293 */
 294
 295extern void __bad_size_call_parameter(void);
 296
 297#ifdef CONFIG_DEBUG_PREEMPT
 298extern void __this_cpu_preempt_check(const char *op);
 299#else
 300static inline void __this_cpu_preempt_check(const char *op) { }
 301#endif
 302
 303#define __pcpu_size_call_return(stem, variable)                         \
 304({                                                                      \
 305        typeof(variable) pscr_ret__;                                    \
 306        __verify_pcpu_ptr(&(variable));                                 \
 307        switch(sizeof(variable)) {                                      \
 308        case 1: pscr_ret__ = stem##1(variable); break;                  \
 309        case 2: pscr_ret__ = stem##2(variable); break;                  \
 310        case 4: pscr_ret__ = stem##4(variable); break;                  \
 311        case 8: pscr_ret__ = stem##8(variable); break;                  \
 312        default:                                                        \
 313                __bad_size_call_parameter(); break;                     \
 314        }                                                               \
 315        pscr_ret__;                                                     \
 316})
 317
 318#define __pcpu_size_call_return2(stem, variable, ...)                   \
 319({                                                                      \
 320        typeof(variable) pscr2_ret__;                                   \
 321        __verify_pcpu_ptr(&(variable));                                 \
 322        switch(sizeof(variable)) {                                      \
 323        case 1: pscr2_ret__ = stem##1(variable, __VA_ARGS__); break;    \
 324        case 2: pscr2_ret__ = stem##2(variable, __VA_ARGS__); break;    \
 325        case 4: pscr2_ret__ = stem##4(variable, __VA_ARGS__); break;    \
 326        case 8: pscr2_ret__ = stem##8(variable, __VA_ARGS__); break;    \
 327        default:                                                        \
 328                __bad_size_call_parameter(); break;                     \
 329        }                                                               \
 330        pscr2_ret__;                                                    \
 331})
 332
 333/*
 334 * Special handling for cmpxchg_double.  cmpxchg_double is passed two
 335 * percpu variables.  The first has to be aligned to a double word
 336 * boundary and the second has to follow directly thereafter.
 337 * We enforce this on all architectures even if they don't support
 338 * a double cmpxchg instruction, since it's a cheap requirement, and it
 339 * avoids breaking the requirement for architectures with the instruction.
 340 */
 341#define __pcpu_double_call_return_bool(stem, pcp1, pcp2, ...)           \
 342({                                                                      \
 343        bool pdcrb_ret__;                                               \
 344        __verify_pcpu_ptr(&(pcp1));                                     \
 345        BUILD_BUG_ON(sizeof(pcp1) != sizeof(pcp2));                     \
 346        VM_BUG_ON((unsigned long)(&(pcp1)) % (2 * sizeof(pcp1)));       \
 347        VM_BUG_ON((unsigned long)(&(pcp2)) !=                           \
 348                  (unsigned long)(&(pcp1)) + sizeof(pcp1));             \
 349        switch(sizeof(pcp1)) {                                          \
 350        case 1: pdcrb_ret__ = stem##1(pcp1, pcp2, __VA_ARGS__); break;  \
 351        case 2: pdcrb_ret__ = stem##2(pcp1, pcp2, __VA_ARGS__); break;  \
 352        case 4: pdcrb_ret__ = stem##4(pcp1, pcp2, __VA_ARGS__); break;  \
 353        case 8: pdcrb_ret__ = stem##8(pcp1, pcp2, __VA_ARGS__); break;  \
 354        default:                                                        \
 355                __bad_size_call_parameter(); break;                     \
 356        }                                                               \
 357        pdcrb_ret__;                                                    \
 358})
 359
 360#define __pcpu_size_call(stem, variable, ...)                           \
 361do {                                                                    \
 362        __verify_pcpu_ptr(&(variable));                                 \
 363        switch(sizeof(variable)) {                                      \
 364                case 1: stem##1(variable, __VA_ARGS__);break;           \
 365                case 2: stem##2(variable, __VA_ARGS__);break;           \
 366                case 4: stem##4(variable, __VA_ARGS__);break;           \
 367                case 8: stem##8(variable, __VA_ARGS__);break;           \
 368                default:                                                \
 369                        __bad_size_call_parameter();break;              \
 370        }                                                               \
 371} while (0)
 372
 373/*
 374 * this_cpu operations (C) 2008-2013 Christoph Lameter <cl@linux.com>
 375 *
 376 * Optimized manipulation for memory allocated through the per cpu
 377 * allocator or for addresses of per cpu variables.
 378 *
 379 * These operation guarantee exclusivity of access for other operations
 380 * on the *same* processor. The assumption is that per cpu data is only
 381 * accessed by a single processor instance (the current one).
 382 *
 383 * The arch code can provide optimized implementation by defining macros
 384 * for certain scalar sizes. F.e. provide this_cpu_add_2() to provide per
 385 * cpu atomic operations for 2 byte sized RMW actions. If arch code does
 386 * not provide operations for a scalar size then the fallback in the
 387 * generic code will be used.
 388 *
 389 * cmpxchg_double replaces two adjacent scalars at once.  The first two
 390 * parameters are per cpu variables which have to be of the same size.  A
 391 * truth value is returned to indicate success or failure (since a double
 392 * register result is difficult to handle).  There is very limited hardware
 393 * support for these operations, so only certain sizes may work.
 394 */
 395
 396/*
 397 * Operations for contexts where we do not want to do any checks for
 398 * preemptions.  Unless strictly necessary, always use [__]this_cpu_*()
 399 * instead.
 400 *
 401 * If there is no other protection through preempt disable and/or disabling
 402 * interupts then one of these RMW operations can show unexpected behavior
 403 * because the execution thread was rescheduled on another processor or an
 404 * interrupt occurred and the same percpu variable was modified from the
 405 * interrupt context.
 406 */
 407#define raw_cpu_read(pcp)               __pcpu_size_call_return(raw_cpu_read_, pcp)
 408#define raw_cpu_write(pcp, val)         __pcpu_size_call(raw_cpu_write_, pcp, val)
 409#define raw_cpu_add(pcp, val)           __pcpu_size_call(raw_cpu_add_, pcp, val)
 410#define raw_cpu_and(pcp, val)           __pcpu_size_call(raw_cpu_and_, pcp, val)
 411#define raw_cpu_or(pcp, val)            __pcpu_size_call(raw_cpu_or_, pcp, val)
 412#define raw_cpu_add_return(pcp, val)    __pcpu_size_call_return2(raw_cpu_add_return_, pcp, val)
 413#define raw_cpu_xchg(pcp, nval)         __pcpu_size_call_return2(raw_cpu_xchg_, pcp, nval)
 414#define raw_cpu_cmpxchg(pcp, oval, nval) \
 415        __pcpu_size_call_return2(raw_cpu_cmpxchg_, pcp, oval, nval)
 416#define raw_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) \
 417        __pcpu_double_call_return_bool(raw_cpu_cmpxchg_double_, pcp1, pcp2, oval1, oval2, nval1, nval2)
 418
 419#define raw_cpu_sub(pcp, val)           raw_cpu_add(pcp, -(val))
 420#define raw_cpu_inc(pcp)                raw_cpu_add(pcp, 1)
 421#define raw_cpu_dec(pcp)                raw_cpu_sub(pcp, 1)
 422#define raw_cpu_sub_return(pcp, val)    raw_cpu_add_return(pcp, -(typeof(pcp))(val))
 423#define raw_cpu_inc_return(pcp)         raw_cpu_add_return(pcp, 1)
 424#define raw_cpu_dec_return(pcp)         raw_cpu_add_return(pcp, -1)
 425
 426/*
 427 * Operations for contexts that are safe from preemption/interrupts.  These
 428 * operations verify that preemption is disabled.
 429 */
 430#define __this_cpu_read(pcp)                                            \
 431({                                                                      \
 432        __this_cpu_preempt_check("read");                               \
 433        raw_cpu_read(pcp);                                              \
 434})
 435
 436#define __this_cpu_write(pcp, val)                                      \
 437({                                                                      \
 438        __this_cpu_preempt_check("write");                              \
 439        raw_cpu_write(pcp, val);                                        \
 440})
 441
 442#define __this_cpu_add(pcp, val)                                        \
 443({                                                                      \
 444        __this_cpu_preempt_check("add");                                \
 445        raw_cpu_add(pcp, val);                                          \
 446})
 447
 448#define __this_cpu_and(pcp, val)                                        \
 449({                                                                      \
 450        __this_cpu_preempt_check("and");                                \
 451        raw_cpu_and(pcp, val);                                          \
 452})
 453
 454#define __this_cpu_or(pcp, val)                                         \
 455({                                                                      \
 456        __this_cpu_preempt_check("or");                                 \
 457        raw_cpu_or(pcp, val);                                           \
 458})
 459
 460#define __this_cpu_add_return(pcp, val)                                 \
 461({                                                                      \
 462        __this_cpu_preempt_check("add_return");                         \
 463        raw_cpu_add_return(pcp, val);                                   \
 464})
 465
 466#define __this_cpu_xchg(pcp, nval)                                      \
 467({                                                                      \
 468        __this_cpu_preempt_check("xchg");                               \
 469        raw_cpu_xchg(pcp, nval);                                        \
 470})
 471
 472#define __this_cpu_cmpxchg(pcp, oval, nval)                             \
 473({                                                                      \
 474        __this_cpu_preempt_check("cmpxchg");                            \
 475        raw_cpu_cmpxchg(pcp, oval, nval);                               \
 476})
 477
 478#define __this_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) \
 479({      __this_cpu_preempt_check("cmpxchg_double");                     \
 480        raw_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2); \
 481})
 482
 483#define __this_cpu_sub(pcp, val)        __this_cpu_add(pcp, -(typeof(pcp))(val))
 484#define __this_cpu_inc(pcp)             __this_cpu_add(pcp, 1)
 485#define __this_cpu_dec(pcp)             __this_cpu_sub(pcp, 1)
 486#define __this_cpu_sub_return(pcp, val) __this_cpu_add_return(pcp, -(typeof(pcp))(val))
 487#define __this_cpu_inc_return(pcp)      __this_cpu_add_return(pcp, 1)
 488#define __this_cpu_dec_return(pcp)      __this_cpu_add_return(pcp, -1)
 489
 490/*
 491 * Operations with implied preemption/interrupt protection.  These
 492 * operations can be used without worrying about preemption or interrupt.
 493 */
 494#define this_cpu_read(pcp)              __pcpu_size_call_return(this_cpu_read_, pcp)
 495#define this_cpu_write(pcp, val)        __pcpu_size_call(this_cpu_write_, pcp, val)
 496#define this_cpu_add(pcp, val)          __pcpu_size_call(this_cpu_add_, pcp, val)
 497#define this_cpu_and(pcp, val)          __pcpu_size_call(this_cpu_and_, pcp, val)
 498#define this_cpu_or(pcp, val)           __pcpu_size_call(this_cpu_or_, pcp, val)
 499#define this_cpu_add_return(pcp, val)   __pcpu_size_call_return2(this_cpu_add_return_, pcp, val)
 500#define this_cpu_xchg(pcp, nval)        __pcpu_size_call_return2(this_cpu_xchg_, pcp, nval)
 501#define this_cpu_cmpxchg(pcp, oval, nval) \
 502        __pcpu_size_call_return2(this_cpu_cmpxchg_, pcp, oval, nval)
 503#define this_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) \
 504        __pcpu_double_call_return_bool(this_cpu_cmpxchg_double_, pcp1, pcp2, oval1, oval2, nval1, nval2)
 505
 506#define this_cpu_sub(pcp, val)          this_cpu_add(pcp, -(typeof(pcp))(val))
 507#define this_cpu_inc(pcp)               this_cpu_add(pcp, 1)
 508#define this_cpu_dec(pcp)               this_cpu_sub(pcp, 1)
 509#define this_cpu_sub_return(pcp, val)   this_cpu_add_return(pcp, -(typeof(pcp))(val))
 510#define this_cpu_inc_return(pcp)        this_cpu_add_return(pcp, 1)
 511#define this_cpu_dec_return(pcp)        this_cpu_add_return(pcp, -1)
 512
 513#endif /* __ASSEMBLY__ */
 514#endif /* _LINUX_PERCPU_DEFS_H */
 515