| 1 | #ifndef __LINUX_COMPILER_H
|
| 2 | #define __LINUX_COMPILER_H
|
| 3 |
|
| 4 | #ifndef __ASSEMBLY__
|
| 5 |
|
| 6 | #ifdef __CHECKER__
|
| 7 | # define __user __attribute__((noderef, address_space(1)))
|
| 8 | # define __kernel __attribute__((address_space(0)))
|
| 9 | # define __safe __attribute__((safe))
|
| 10 | # define __force __attribute__((force))
|
| 11 | # define __nocast __attribute__((nocast))
|
| 12 | # define __iomem __attribute__((noderef, address_space(2)))
|
| 13 | # define __must_hold(x) __attribute__((context(x,1,1)))
|
| 14 | # define __acquires(x) __attribute__((context(x,0,1)))
|
| 15 | # define __releases(x) __attribute__((context(x,1,0)))
|
| 16 | # define __acquire(x) __context__(x,1)
|
| 17 | # define __release(x) __context__(x,-1)
|
| 18 | # define __cond_lock(x,c) ((c) ? ({ __acquire(x); 1; }) : 0)
|
| 19 | # define __percpu __attribute__((noderef, address_space(3)))
|
| 20 | # define __pmem __attribute__((noderef, address_space(5)))
|
| 21 | #ifdef CONFIG_SPARSE_RCU_POINTER
|
| 22 | # define __rcu __attribute__((noderef, address_space(4)))
|
| 23 | #else
|
| 24 | # define __rcu
|
| 25 | #endif
|
| 26 | # define __private __attribute__((noderef))
|
| 27 | extern void __chk_user_ptr(const volatile void __user *);
|
| 28 | extern void __chk_io_ptr(const volatile void __iomem *);
|
| 29 | # define ACCESS_PRIVATE(p, member) (*((typeof((p)->member) __force *) &(p)->member))
|
| 30 | #else
|
| 31 | # define __user
|
| 32 | # define __kernel
|
| 33 | # define __safe
|
| 34 | # define __force
|
| 35 | # define __nocast
|
| 36 | # define __iomem
|
| 37 | # define __chk_user_ptr(x) (void)0
|
| 38 | # define __chk_io_ptr(x) (void)0
|
| 39 | # define __builtin_warning(x, y...) (1)
|
| 40 | # define __must_hold(x)
|
| 41 | # define __acquires(x)
|
| 42 | # define __releases(x)
|
| 43 | # define __acquire(x) (void)0
|
| 44 | # define __release(x) (void)0
|
| 45 | # define __cond_lock(x,c) (c)
|
| 46 | # define __percpu
|
| 47 | # define __rcu
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| 48 | # define __pmem
|
| 49 | # define __private
|
| 50 | # define ACCESS_PRIVATE(p, member) ((p)->member)
|
| 51 | #endif
|
| 52 |
|
| 53 |
|
| 54 | #define ___PASTE(a,b) a##b
|
| 55 | #define __PASTE(a,b) ___PASTE(a,b)
|
| 56 |
|
| 57 | #ifdef __KERNEL__
|
| 58 |
|
| 59 | #ifdef __GNUC__
|
| 60 | #include <linux/compiler-gcc.h>
|
| 61 | #endif
|
| 62 |
|
| 63 | #if defined(CC_USING_HOTPATCH) && !defined(__CHECKER__)
|
| 64 | #define notrace __attribute__((hotpatch(0,0)))
|
| 65 | #else
|
| 66 | #define notrace __attribute__((no_instrument_function))
|
| 67 | #endif
|
| 68 |
|
| 69 | |
| 70 | * coming from above header files here
|
| 71 |
|
| 72 | #ifdef __INTEL_COMPILER
|
| 73 | # include <linux/compiler-intel.h>
|
| 74 | #endif
|
| 75 |
|
| 76 | |
| 77 | * coming from above header files here
|
| 78 |
|
| 79 | #ifdef __clang__
|
| 80 | #include <linux/compiler-clang.h>
|
| 81 | #endif
|
| 82 |
|
| 83 | |
| 84 | * Generic compiler-dependent macros required for kernel
|
| 85 | * build go below this comment. Actual compiler/compiler version
|
| 86 | * specific implementations come from the above header files
|
| 87 |
|
| 88 |
|
| 89 | struct ftrace_branch_data {
|
| 90 | const char *func;
|
| 91 | const char *file;
|
| 92 | unsigned line;
|
| 93 | union {
|
| 94 | struct {
|
| 95 | unsigned long correct;
|
| 96 | unsigned long incorrect;
|
| 97 | };
|
| 98 | struct {
|
| 99 | unsigned long miss;
|
| 100 | unsigned long hit;
|
| 101 | };
|
| 102 | unsigned long miss_hit[2];
|
| 103 | };
|
| 104 | };
|
| 105 |
|
| 106 | |
| 107 | * Note: DISABLE_BRANCH_PROFILING can be used by special lowlevel code
|
| 108 | * to disable branch tracing on a per file basis.
|
| 109 |
|
| 110 | #if defined(CONFIG_TRACE_BRANCH_PROFILING) \
|
| 111 | && !defined(DISABLE_BRANCH_PROFILING) && !defined(__CHECKER__)
|
| 112 | void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
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| 113 |
|
| 114 | #define likely_notrace(x) __builtin_expect(!!(x), 1)
|
| 115 | #define unlikely_notrace(x) __builtin_expect(!!(x), 0)
|
| 116 |
|
| 117 | #define __branch_check__(x, expect) ({ \
|
| 118 | int ______r; \
|
| 119 | static struct ftrace_branch_data \
|
| 120 | __attribute__((__aligned__(4))) \
|
| 121 | __attribute__((section("_ftrace_annotated_branch"))) \
|
| 122 | ______f = { \
|
| 123 | .func = __func__, \
|
| 124 | .file = __FILE__, \
|
| 125 | .line = __LINE__, \
|
| 126 | }; \
|
| 127 | ______r = likely_notrace(x); \
|
| 128 | ftrace_likely_update(&______f, ______r, expect); \
|
| 129 | ______r; \
|
| 130 | })
|
| 131 |
|
| 132 | |
| 133 | * Using __builtin_constant_p(x) to ignore cases where the return
|
| 134 | * value is always the same. This idea is taken from a similar patch
|
| 135 | * written by Daniel Walker.
|
| 136 |
|
| 137 | # ifndef likely
|
| 138 | # define likely(x) (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 1))
|
| 139 | # endif
|
| 140 | # ifndef unlikely
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| 141 | # define unlikely(x) (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 0))
|
| 142 | # endif
|
| 143 |
|
| 144 | #ifdef CONFIG_PROFILE_ALL_BRANCHES
|
| 145 | |
| 146 | * "Define 'is'", Bill Clinton
|
| 147 | * "Define 'if'", Steven Rostedt
|
| 148 |
|
| 149 | #define if(cond, ...) __trace_if( (cond , ## __VA_ARGS__) )
|
| 150 | #define __trace_if(cond) \
|
| 151 | if (__builtin_constant_p(!!(cond)) ? !!(cond) : \
|
| 152 | ({ \
|
| 153 | int ______r; \
|
| 154 | static struct ftrace_branch_data \
|
| 155 | __attribute__((__aligned__(4))) \
|
| 156 | __attribute__((section("_ftrace_branch"))) \
|
| 157 | ______f = { \
|
| 158 | .func = __func__, \
|
| 159 | .file = __FILE__, \
|
| 160 | .line = __LINE__, \
|
| 161 | }; \
|
| 162 | ______r = !!(cond); \
|
| 163 | ______f.miss_hit[______r]++; \
|
| 164 | ______r; \
|
| 165 | }))
|
| 166 | #endif
|
| 167 |
|
| 168 | #else
|
| 169 | # define likely(x) __builtin_expect(!!(x), 1)
|
| 170 | # define unlikely(x) __builtin_expect(!!(x), 0)
|
| 171 | #endif
|
| 172 |
|
| 173 |
|
| 174 | #ifndef barrier
|
| 175 | # define barrier() __memory_barrier()
|
| 176 | #endif
|
| 177 |
|
| 178 | #ifndef barrier_data
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| 179 | # define barrier_data(ptr) barrier()
|
| 180 | #endif
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| 181 |
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| 182 |
|
| 183 | #ifndef unreachable
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| 184 | # define unreachable() do { } while (1)
|
| 185 | #endif
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| 186 |
|
| 187 | #ifndef RELOC_HIDE
|
| 188 | # define RELOC_HIDE(ptr, off) \
|
| 189 | ({ unsigned long __ptr; \
|
| 190 | __ptr = (unsigned long) (ptr); \
|
| 191 | (typeof(ptr)) (__ptr + (off)); })
|
| 192 | #endif
|
| 193 |
|
| 194 | #ifndef OPTIMIZER_HIDE_VAR
|
| 195 | #define OPTIMIZER_HIDE_VAR(var) barrier()
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| 196 | #endif
|
| 197 |
|
| 198 |
|
| 199 | #ifndef __UNIQUE_ID
|
| 200 | # define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __LINE__)
|
| 201 | #endif
|
| 202 |
|
| 203 | #include <uapi/linux/types.h>
|
| 204 |
|
| 205 | #define __READ_ONCE_SIZE \
|
| 206 | ({ \
|
| 207 | switch (size) { \
|
| 208 | case 1: *(__u8 *)res = *(volatile __u8 *)p; break; \
|
| 209 | case 2: *(__u16 *)res = *(volatile __u16 *)p; break; \
|
| 210 | case 4: *(__u32 *)res = *(volatile __u32 *)p; break; \
|
| 211 | case 8: *(__u64 *)res = *(volatile __u64 *)p; break; \
|
| 212 | default: \
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| 213 | barrier(); \
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| 214 | __builtin_memcpy((void *)res, (const void *)p, size); \
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| 215 | barrier(); \
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| 216 | } \
|
| 217 | })
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| 218 |
|
| 219 | static __always_inline
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| 220 | void __read_once_size(const volatile void *p, void *res, int size)
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| 221 | {
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| 222 | __READ_ONCE_SIZE;
|
| 223 | }
|
| 224 |
|
| 225 | #ifdef CONFIG_KASAN
|
| 226 | |
| 227 | * This function is not 'inline' because __no_sanitize_address confilcts
|
| 228 | * with inlining. Attempt to inline it may cause a build failure.
|
| 229 | * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368
|
| 230 | * '__maybe_unused' allows us to avoid defined-but-not-used warnings.
|
| 231 |
|
| 232 | static __no_sanitize_address __maybe_unused
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| 233 | void __read_once_size_nocheck(const volatile void *p, void *res, int size)
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| 234 | {
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| 235 | __READ_ONCE_SIZE;
|
| 236 | }
|
| 237 | #else
|
| 238 | static __always_inline
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| 239 | void __read_once_size_nocheck(const volatile void *p, void *res, int size)
|
| 240 | {
|
| 241 | __READ_ONCE_SIZE;
|
| 242 | }
|
| 243 | #endif
|
| 244 |
|
| 245 | static __always_inline void __write_once_size(volatile void *p, void *res, int size)
|
| 246 | {
|
| 247 | switch (size) {
|
| 248 | case 1: *(volatile __u8 *)p = *(__u8 *)res; break;
|
| 249 | case 2: *(volatile __u16 *)p = *(__u16 *)res; break;
|
| 250 | case 4: *(volatile __u32 *)p = *(__u32 *)res; break;
|
| 251 | case 8: *(volatile __u64 *)p = *(__u64 *)res; break;
|
| 252 | default:
|
| 253 | barrier();
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| 254 | __builtin_memcpy((void *)p, (const void *)res, size);
|
| 255 | barrier();
|
| 256 | }
|
| 257 | }
|
| 258 |
|
| 259 | |
| 260 | * Prevent the compiler from merging or refetching reads or writes. The
|
| 261 | * compiler is also forbidden from reordering successive instances of
|
| 262 | * READ_ONCE, WRITE_ONCE and ACCESS_ONCE (see below), but only when the
|
| 263 | * compiler is aware of some particular ordering. One way to make the
|
| 264 | * compiler aware of ordering is to put the two invocations of READ_ONCE,
|
| 265 | * WRITE_ONCE or ACCESS_ONCE() in different C statements.
|
| 266 | *
|
| 267 | * In contrast to ACCESS_ONCE these two macros will also work on aggregate
|
| 268 | * data types like structs or unions. If the size of the accessed data
|
| 269 | * type exceeds the word size of the machine (e.g., 32 bits or 64 bits)
|
| 270 | * READ_ONCE() and WRITE_ONCE() will fall back to memcpy(). There's at
|
| 271 | * least two memcpy()s: one for the __builtin_memcpy() and then one for
|
| 272 | * the macro doing the copy of variable - '__u' allocated on the stack.
|
| 273 | *
|
| 274 | * Their two major use cases are: (1) Mediating communication between
|
| 275 | * process-level code and irq/NMI handlers, all running on the same CPU,
|
| 276 | * and (2) Ensuring that the compiler does not fold, spindle, or otherwise
|
| 277 | * mutilate accesses that either do not require ordering or that interact
|
| 278 | * with an explicit memory barrier or atomic instruction that provides the
|
| 279 | * required ordering.
|
| 280 |
|
| 281 |
|
| 282 | #define __READ_ONCE(x, check) \
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| 283 | ({ \
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| 284 | union { typeof(x) __val; char __c[1]; } __u; \
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| 285 | if (check) \
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| 286 | __read_once_size(&(x), __u.__c, sizeof(x)); \
|
| 287 | else \
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| 288 | __read_once_size_nocheck(&(x), __u.__c, sizeof(x)); \
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| 289 | __u.__val; \
|
| 290 | })
|
| 291 | #define READ_ONCE(x) __READ_ONCE(x, 1)
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| 292 |
|
| 293 | |
| 294 | * Use READ_ONCE_NOCHECK() instead of READ_ONCE() if you need
|
| 295 | * to hide memory access from KASAN.
|
| 296 |
|
| 297 | #define READ_ONCE_NOCHECK(x) __READ_ONCE(x, 0)
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| 298 |
|
| 299 | #define WRITE_ONCE(x, val) \
|
| 300 | ({ \
|
| 301 | union { typeof(x) __val; char __c[1]; } __u = \
|
| 302 | { .__val = (__force typeof(x)) (val) }; \
|
| 303 | __write_once_size(&(x), __u.__c, sizeof(x)); \
|
| 304 | __u.__val; \
|
| 305 | })
|
| 306 |
|
| 307 | |
| 308 | * smp_cond_acquire() - Spin wait for cond with ACQUIRE ordering
|
| 309 | * @cond: boolean expression to wait for
|
| 310 | *
|
| 311 | * Equivalent to using smp_load_acquire() on the condition variable but employs
|
| 312 | * the control dependency of the wait to reduce the barrier on many platforms.
|
| 313 | *
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| 314 | * The control dependency provides a LOAD->STORE order, the additional RMB
|
| 315 | * provides LOAD->LOAD order, together they provide LOAD->{LOAD,STORE} order,
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| 316 | * aka. ACQUIRE.
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| 317 |
|
| 318 | #define smp_cond_acquire(cond) do { \
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| 319 | while (!(cond)) \
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| 320 | cpu_relax(); \
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| 321 | smp_rmb(); \
|
| 322 | } while (0)
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| 323 |
|
| 324 | #endif
|
| 325 |
|
| 326 | #endif
|
| 327 |
|
| 328 | #ifdef __KERNEL__
|
| 329 | |
| 330 | * Allow us to mark functions as 'deprecated' and have gcc emit a nice
|
| 331 | * warning for each use, in hopes of speeding the functions removal.
|
| 332 | * Usage is:
|
| 333 | * int __deprecated foo(void)
|
| 334 |
|
| 335 | #ifndef __deprecated
|
| 336 | # define __deprecated
|
| 337 | #endif
|
| 338 |
|
| 339 | #ifdef MODULE
|
| 340 | #define __deprecated_for_modules __deprecated
|
| 341 | #else
|
| 342 | #define __deprecated_for_modules
|
| 343 | #endif
|
| 344 |
|
| 345 | #ifndef __must_check
|
| 346 | #define __must_check
|
| 347 | #endif
|
| 348 |
|
| 349 | #ifndef CONFIG_ENABLE_MUST_CHECK
|
| 350 | #undef __must_check
|
| 351 | #define __must_check
|
| 352 | #endif
|
| 353 | #ifndef CONFIG_ENABLE_WARN_DEPRECATED
|
| 354 | #undef __deprecated
|
| 355 | #undef __deprecated_for_modules
|
| 356 | #define __deprecated
|
| 357 | #define __deprecated_for_modules
|
| 358 | #endif
|
| 359 |
|
| 360 | #ifndef __malloc
|
| 361 | #define __malloc
|
| 362 | #endif
|
| 363 |
|
| 364 | |
| 365 | * Allow us to avoid 'defined but not used' warnings on functions and data,
|
| 366 | * as well as force them to be emitted to the assembly file.
|
| 367 | *
|
| 368 | * As of gcc 3.4, static functions that are not marked with attribute((used))
|
| 369 | * may be elided from the assembly file. As of gcc 3.4, static data not so
|
| 370 | * marked will not be elided, but this may change in a future gcc version.
|
| 371 | *
|
| 372 | * NOTE: Because distributions shipped with a backported unit-at-a-time
|
| 373 | * compiler in gcc 3.3, we must define __used to be __attribute__((used))
|
| 374 | * for gcc >=3.3 instead of 3.4.
|
| 375 | *
|
| 376 | * In prior versions of gcc, such functions and data would be emitted, but
|
| 377 | * would be warned about except with attribute((unused)).
|
| 378 | *
|
| 379 | * Mark functions that are referenced only in inline assembly as __used so
|
| 380 | * the code is emitted even though it appears to be unreferenced.
|
| 381 |
|
| 382 | #ifndef __used
|
| 383 | # define __used
|
| 384 | #endif
|
| 385 |
|
| 386 | #ifndef __maybe_unused
|
| 387 | # define __maybe_unused
|
| 388 | #endif
|
| 389 |
|
| 390 | #ifndef __always_unused
|
| 391 | # define __always_unused
|
| 392 | #endif
|
| 393 |
|
| 394 | #ifndef noinline
|
| 395 | #define noinline
|
| 396 | #endif
|
| 397 |
|
| 398 | |
| 399 | * Rather then using noinline to prevent stack consumption, use
|
| 400 | * noinline_for_stack instead. For documentation reasons.
|
| 401 |
|
| 402 | #define noinline_for_stack noinline
|
| 403 |
|
| 404 | #ifndef __always_inline
|
| 405 | #define __always_inline inline
|
| 406 | #endif
|
| 407 |
|
| 408 | #endif
|
| 409 |
|
| 410 | |
| 411 | * From the GCC manual:
|
| 412 | *
|
| 413 | * Many functions do not examine any values except their arguments,
|
| 414 | * and have no effects except the return value. Basically this is
|
| 415 | * just slightly more strict class than the `pure' attribute above,
|
| 416 | * since function is not allowed to read global memory.
|
| 417 | *
|
| 418 | * Note that a function that has pointer arguments and examines the
|
| 419 | * data pointed to must _not_ be declared `const'. Likewise, a
|
| 420 | * function that calls a non-`const' function usually must not be
|
| 421 | * `const'. It does not make sense for a `const' function to return
|
| 422 | * `void'.
|
| 423 |
|
| 424 | #ifndef __attribute_const__
|
| 425 | # define __attribute_const__
|
| 426 | #endif
|
| 427 |
|
| 428 | |
| 429 | * Tell gcc if a function is cold. The compiler will assume any path
|
| 430 | * directly leading to the call is unlikely.
|
| 431 |
|
| 432 |
|
| 433 | #ifndef __cold
|
| 434 | #define __cold
|
| 435 | #endif
|
| 436 |
|
| 437 |
|
| 438 | #ifndef __section
|
| 439 | # define __section(S) __attribute__ ((__section__(#S)))
|
| 440 | #endif
|
| 441 |
|
| 442 | #ifndef __visible
|
| 443 | #define __visible
|
| 444 | #endif
|
| 445 |
|
| 446 | |
| 447 | * Assume alignment of return value.
|
| 448 |
|
| 449 | #ifndef __assume_aligned
|
| 450 | #define __assume_aligned(a, ...)
|
| 451 | #endif
|
| 452 |
|
| 453 |
|
| 454 |
|
| 455 | #ifndef __same_type
|
| 456 | # define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
|
| 457 | #endif
|
| 458 |
|
| 459 |
|
| 460 | #ifndef __native_word
|
| 461 | # define __native_word(t) (sizeof(t) == sizeof(char) || sizeof(t) == sizeof(short) || sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long))
|
| 462 | #endif
|
| 463 |
|
| 464 |
|
| 465 | #ifndef __compiletime_object_size
|
| 466 | # define __compiletime_object_size(obj) -1
|
| 467 | #endif
|
| 468 | #ifndef __compiletime_warning
|
| 469 | # define __compiletime_warning(message)
|
| 470 | #endif
|
| 471 | #ifndef __compiletime_error
|
| 472 | # define __compiletime_error(message)
|
| 473 | |
| 474 | * Sparse complains of variable sized arrays due to the temporary variable in
|
| 475 | * __compiletime_assert. Unfortunately we can't just expand it out to make
|
| 476 | * sparse see a constant array size without breaking compiletime_assert on old
|
| 477 | * versions of GCC (e.g. 4.2.4), so hide the array from sparse altogether.
|
| 478 |
|
| 479 | # ifndef __CHECKER__
|
| 480 | # define __compiletime_error_fallback(condition) \
|
| 481 | do { ((void)sizeof(char[1 - 2 * condition])); } while (0)
|
| 482 | # endif
|
| 483 | #endif
|
| 484 | #ifndef __compiletime_error_fallback
|
| 485 | # define __compiletime_error_fallback(condition) do { } while (0)
|
| 486 | #endif
|
| 487 |
|
| 488 | #define __compiletime_assert(condition, msg, prefix, suffix) \
|
| 489 | do { \
|
| 490 | bool __cond = !(condition); \
|
| 491 | extern void prefix ## suffix(void) __compiletime_error(msg); \
|
| 492 | if (__cond) \
|
| 493 | prefix ## suffix(); \
|
| 494 | __compiletime_error_fallback(__cond); \
|
| 495 | } while (0)
|
| 496 |
|
| 497 | #define _compiletime_assert(condition, msg, prefix, suffix) \
|
| 498 | __compiletime_assert(condition, msg, prefix, suffix)
|
| 499 |
|
| 500 | |
| 501 | * compiletime_assert - break build and emit msg if condition is false
|
| 502 | * @condition: a compile-time constant condition to check
|
| 503 | * @msg: a message to emit if condition is false
|
| 504 | *
|
| 505 | * In tradition of POSIX assert, this macro will break the build if the
|
| 506 | * supplied condition is *false*, emitting the supplied error message if the
|
| 507 | * compiler has support to do so.
|
| 508 |
|
| 509 | #define compiletime_assert(condition, msg) \
|
| 510 | _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
|
| 511 |
|
| 512 | #define compiletime_assert_atomic_type(t) \
|
| 513 | compiletime_assert(__native_word(t), \
|
| 514 | "Need native word sized stores/loads for atomicity.")
|
| 515 |
|
| 516 | |
| 517 | * Prevent the compiler from merging or refetching accesses. The compiler
|
| 518 | * is also forbidden from reordering successive instances of ACCESS_ONCE(),
|
| 519 | * but only when the compiler is aware of some particular ordering. One way
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| 520 | * to make the compiler aware of ordering is to put the two invocations of
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| 521 | * ACCESS_ONCE() in different C statements.
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| 522 | *
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| 523 | * ACCESS_ONCE will only work on scalar types. For union types, ACCESS_ONCE
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| 524 | * on a union member will work as long as the size of the member matches the
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| 525 | * size of the union and the size is smaller than word size.
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| 526 | *
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| 527 | * The major use cases of ACCESS_ONCE used to be (1) Mediating communication
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| 528 | * between process-level code and irq/NMI handlers, all running on the same CPU,
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| 529 | * and (2) Ensuring that the compiler does not fold, spindle, or otherwise
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| 530 | * mutilate accesses that either do not require ordering or that interact
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| 531 | * with an explicit memory barrier or atomic instruction that provides the
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| 532 | * required ordering.
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| 533 | *
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| 534 | * If possible use READ_ONCE()/WRITE_ONCE() instead.
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| 535 |
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| 536 | #define __ACCESS_ONCE(x) ({ \
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| 537 | __maybe_unused typeof(x) __var = (__force typeof(x)) 0; \
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| 538 | (volatile typeof(x) *)&(x); })
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| 539 | #define ACCESS_ONCE(x) (*__ACCESS_ONCE(x))
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| 540 |
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| 541 | |
| 542 | * lockless_dereference() - safely load a pointer for later dereference
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| 543 | * @p: The pointer to load
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| 544 | *
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| 545 | * Similar to rcu_dereference(), but for situations where the pointed-to
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| 546 | * object's lifetime is managed by something other than RCU. That
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| 547 | * "something other" might be reference counting or simple immortality.
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| 548 |
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| 549 | #define lockless_dereference(p) \
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| 550 | ({ \
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| 551 | typeof(p) _________p1 = READ_ONCE(p); \
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| 552 | smp_read_barrier_depends(); \
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| 553 | (_________p1); \
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| 554 | })
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| 555 |
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| 556 |
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| 557 | #ifdef CONFIG_KPROBES
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| 558 | # define __kprobes __attribute__((__section__(".kprobes.text")))
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| 559 | # define nokprobe_inline __always_inline
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| 560 | #else
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| 561 | # define __kprobes
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| 562 | # define nokprobe_inline inline
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| 563 | #endif
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| 564 | #endif
|