1 #ifndef _LINUX_KERNEL_H 2 #define _LINUX_KERNEL_H 3 4 5 #include <stdarg.h> 6 #include <linux/linkage.h> 7 #include <linux/stddef.h> 8 #include <linux/types.h> 9 #include <linux/compiler.h> 10 #include <linux/bitops.h> 11 #include <linux/log2.h> 12 #include <linux/typecheck.h> 13 #include <linux/printk.h> 14 #include <linux/build_bug.h> 15 #include <asm/byteorder.h> 16 #include <uapi/linux/kernel.h> 17 18 #define USHRT_MAX ((u16)(~0U)) 19 #define SHRT_MAX ((s16)(USHRT_MAX>>1)) 20 #define SHRT_MIN ((s16)(-SHRT_MAX - 1)) 21 #define INT_MAX ((int)(~0U>>1)) 22 #define INT_MIN (-INT_MAX - 1) 23 #define UINT_MAX (~0U) 24 #define LONG_MAX ((long)(~0UL>>1)) 25 #define LONG_MIN (-LONG_MAX - 1) 26 #define ULONG_MAX (~0UL) 27 #define LLONG_MAX ((long long)(~0ULL>>1)) 28 #define LLONG_MIN (-LLONG_MAX - 1) 29 #define ULLONG_MAX (~0ULL) 30 #define SIZE_MAX (~(size_t)0) 31 32 #define U8_MAX ((u8)~0U) 33 #define S8_MAX ((s8)(U8_MAX>>1)) 34 #define S8_MIN ((s8)(-S8_MAX - 1)) 35 #define U16_MAX ((u16)~0U) 36 #define S16_MAX ((s16)(U16_MAX>>1)) 37 #define S16_MIN ((s16)(-S16_MAX - 1)) 38 #define U32_MAX ((u32)~0U) 39 #define S32_MAX ((s32)(U32_MAX>>1)) 40 #define S32_MIN ((s32)(-S32_MAX - 1)) 41 #define U64_MAX ((u64)~0ULL) 42 #define S64_MAX ((s64)(U64_MAX>>1)) 43 #define S64_MIN ((s64)(-S64_MAX - 1)) 44 45 #define STACK_MAGIC 0xdeadbeef 46 47 #define REPEAT_BYTE(x) ((~0ul / 0xff) * (x)) 48 49 /* @a is a power of 2 value */ 50 #define ALIGN(x, a) __ALIGN_KERNEL((x), (a)) 51 #define ALIGN_DOWN(x, a) __ALIGN_KERNEL((x) - ((a) - 1), (a)) 52 #define __ALIGN_MASK(x, mask) __ALIGN_KERNEL_MASK((x), (mask)) 53 #define PTR_ALIGN(p, a) ((typeof(p))ALIGN((unsigned long)(p), (a))) 54 #define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0) 55 56 /* generic data direction definitions */ 57 #define READ 0 58 #define WRITE 1 59 60 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr)) 61 62 #define u64_to_user_ptr(x) ( \ 63 { \ 64 typecheck(u64, x); \ 65 (void __user *)(uintptr_t)x; \ 66 } \ 67 ) 68 69 /* 70 * This looks more complex than it should be. But we need to 71 * get the type for the ~ right in round_down (it needs to be 72 * as wide as the result!), and we want to evaluate the macro 73 * arguments just once each. 74 */ 75 #define __round_mask(x, y) ((__typeof__(x))((y)-1)) 76 #define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1) 77 #define round_down(x, y) ((x) & ~__round_mask(x, y)) 78 79 #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f)) 80 #define DIV_ROUND_UP __KERNEL_DIV_ROUND_UP 81 82 #define DIV_ROUND_DOWN_ULL(ll, d) \ 83 ({ unsigned long long _tmp = (ll); do_div(_tmp, d); _tmp; }) 84 85 #define DIV_ROUND_UP_ULL(ll, d) DIV_ROUND_DOWN_ULL((ll) + (d) - 1, (d)) 86 87 #if BITS_PER_LONG == 32 88 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d) 89 #else 90 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d) 91 #endif 92 93 /* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */ 94 #define roundup(x, y) ( \ 95 { \ 96 const typeof(y) __y = y; \ 97 (((x) + (__y - 1)) / __y) * __y; \ 98 } \ 99 ) 100 #define rounddown(x, y) ( \ 101 { \ 102 typeof(x) __x = (x); \ 103 __x - (__x % (y)); \ 104 } \ 105 ) 106 107 /* 108 * Divide positive or negative dividend by positive or negative divisor 109 * and round to closest integer. Result is undefined for negative 110 * divisors if he dividend variable type is unsigned and for negative 111 * dividends if the divisor variable type is unsigned. 112 */ 113 #define DIV_ROUND_CLOSEST(x, divisor)( \ 114 { \ 115 typeof(x) __x = x; \ 116 typeof(divisor) __d = divisor; \ 117 (((typeof(x))-1) > 0 || \ 118 ((typeof(divisor))-1) > 0 || \ 119 (((__x) > 0) == ((__d) > 0))) ? \ 120 (((__x) + ((__d) / 2)) / (__d)) : \ 121 (((__x) - ((__d) / 2)) / (__d)); \ 122 } \ 123 ) 124 /* 125 * Same as above but for u64 dividends. divisor must be a 32-bit 126 * number. 127 */ 128 #define DIV_ROUND_CLOSEST_ULL(x, divisor)( \ 129 { \ 130 typeof(divisor) __d = divisor; \ 131 unsigned long long _tmp = (x) + (__d) / 2; \ 132 do_div(_tmp, __d); \ 133 _tmp; \ 134 } \ 135 ) 136 137 /* 138 * Multiplies an integer by a fraction, while avoiding unnecessary 139 * overflow or loss of precision. 140 */ 141 #define mult_frac(x, numer, denom)( \ 142 { \ 143 typeof(x) quot = (x) / (denom); \ 144 typeof(x) rem = (x) % (denom); \ 145 (quot * (numer)) + ((rem * (numer)) / (denom)); \ 146 } \ 147 ) 148 149 150 #define _RET_IP_ (unsigned long)__builtin_return_address(0) 151 #define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; }) 152 153 #ifdef CONFIG_LBDAF 154 # include <asm/div64.h> 155 # define sector_div(a, b) do_div(a, b) 156 #else 157 # define sector_div(n, b)( \ 158 { \ 159 int _res; \ 160 _res = (n) % (b); \ 161 (n) /= (b); \ 162 _res; \ 163 } \ 164 ) 165 #endif 166 167 /** 168 * upper_32_bits - return bits 32-63 of a number 169 * @n: the number we're accessing 170 * 171 * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress 172 * the "right shift count >= width of type" warning when that quantity is 173 * 32-bits. 174 */ 175 #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16)) 176 177 /** 178 * lower_32_bits - return bits 0-31 of a number 179 * @n: the number we're accessing 180 */ 181 #define lower_32_bits(n) ((u32)(n)) 182 183 struct completion; 184 struct pt_regs; 185 struct user; 186 187 #ifdef CONFIG_PREEMPT_VOLUNTARY 188 extern int _cond_resched(void); 189 # define might_resched() _cond_resched() 190 #else 191 # define might_resched() do { } while (0) 192 #endif 193 194 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP 195 void ___might_sleep(const char *file, int line, int preempt_offset); 196 void __might_sleep(const char *file, int line, int preempt_offset); 197 /** 198 * might_sleep - annotation for functions that can sleep 199 * 200 * this macro will print a stack trace if it is executed in an atomic 201 * context (spinlock, irq-handler, ...). 202 * 203 * This is a useful debugging help to be able to catch problems early and not 204 * be bitten later when the calling function happens to sleep when it is not 205 * supposed to. 206 */ 207 # define might_sleep() \ 208 do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0) 209 # define sched_annotate_sleep() (current->task_state_change = 0) 210 #else 211 static inline void ___might_sleep(const char *file, int line, 212 int preempt_offset) { } 213 static inline void __might_sleep(const char *file, int line, 214 int preempt_offset) { } 215 # define might_sleep() do { might_resched(); } while (0) 216 # define sched_annotate_sleep() do { } while (0) 217 #endif 218 219 #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0) 220 221 /** 222 * abs - return absolute value of an argument 223 * @x: the value. If it is unsigned type, it is converted to signed type first. 224 * char is treated as if it was signed (regardless of whether it really is) 225 * but the macro's return type is preserved as char. 226 * 227 * Return: an absolute value of x. 228 */ 229 #define abs(x) __abs_choose_expr(x, long long, \ 230 __abs_choose_expr(x, long, \ 231 __abs_choose_expr(x, int, \ 232 __abs_choose_expr(x, short, \ 233 __abs_choose_expr(x, char, \ 234 __builtin_choose_expr( \ 235 __builtin_types_compatible_p(typeof(x), char), \ 236 (char)({ signed char __x = (x); __x<0?-__x:__x; }), \ 237 ((void)0))))))) 238 239 #define __abs_choose_expr(x, type, other) __builtin_choose_expr( \ 240 __builtin_types_compatible_p(typeof(x), signed type) || \ 241 __builtin_types_compatible_p(typeof(x), unsigned type), \ 242 ({ signed type __x = (x); __x < 0 ? -__x : __x; }), other) 243 244 /** 245 * reciprocal_scale - "scale" a value into range [0, ep_ro) 246 * @val: value 247 * @ep_ro: right open interval endpoint 248 * 249 * Perform a "reciprocal multiplication" in order to "scale" a value into 250 * range [0, ep_ro), where the upper interval endpoint is right-open. 251 * This is useful, e.g. for accessing a index of an array containing 252 * ep_ro elements, for example. Think of it as sort of modulus, only that 253 * the result isn't that of modulo. ;) Note that if initial input is a 254 * small value, then result will return 0. 255 * 256 * Return: a result based on val in interval [0, ep_ro). 257 */ 258 static inline u32 reciprocal_scale(u32 val, u32 ep_ro) 259 { 260 return (u32)(((u64) val * ep_ro) >> 32); 261 } 262 263 #if defined(CONFIG_MMU) && \ 264 (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP)) 265 #define might_fault() __might_fault(__FILE__, __LINE__) 266 void __might_fault(const char *file, int line); 267 #else 268 static inline void might_fault(void) { } 269 #endif 270 271 extern struct atomic_notifier_head panic_notifier_list; 272 extern long (*panic_blink)(int state); 273 __printf(1, 2) 274 void panic(const char *fmt, ...) __noreturn __cold; 275 void nmi_panic(struct pt_regs *regs, const char *msg); 276 extern void oops_enter(void); 277 extern void oops_exit(void); 278 void print_oops_end_marker(void); 279 extern int oops_may_print(void); 280 void do_exit(long error_code) __noreturn; 281 void complete_and_exit(struct completion *, long) __noreturn; 282 283 #ifdef CONFIG_ARCH_HAS_REFCOUNT 284 void refcount_error_report(struct pt_regs *regs, const char *err); 285 #else 286 static inline void refcount_error_report(struct pt_regs *regs, const char *err) 287 { } 288 #endif 289 290 /* Internal, do not use. */ 291 int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res); 292 int __must_check _kstrtol(const char *s, unsigned int base, long *res); 293 294 int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res); 295 int __must_check kstrtoll(const char *s, unsigned int base, long long *res); 296 297 /** 298 * kstrtoul - convert a string to an unsigned long 299 * @s: The start of the string. The string must be null-terminated, and may also 300 * include a single newline before its terminating null. The first character 301 * may also be a plus sign, but not a minus sign. 302 * @base: The number base to use. The maximum supported base is 16. If base is 303 * given as 0, then the base of the string is automatically detected with the 304 * conventional semantics - If it begins with 0x the number will be parsed as a 305 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be 306 * parsed as an octal number. Otherwise it will be parsed as a decimal. 307 * @res: Where to write the result of the conversion on success. 308 * 309 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error. 310 * Used as a replacement for the obsolete simple_strtoull. Return code must 311 * be checked. 312 */ 313 static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res) 314 { 315 /* 316 * We want to shortcut function call, but 317 * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0. 318 */ 319 if (sizeof(unsigned long) == sizeof(unsigned long long) && 320 __alignof__(unsigned long) == __alignof__(unsigned long long)) 321 return kstrtoull(s, base, (unsigned long long *)res); 322 else 323 return _kstrtoul(s, base, res); 324 } 325 326 /** 327 * kstrtol - convert a string to a long 328 * @s: The start of the string. The string must be null-terminated, and may also 329 * include a single newline before its terminating null. The first character 330 * may also be a plus sign or a minus sign. 331 * @base: The number base to use. The maximum supported base is 16. If base is 332 * given as 0, then the base of the string is automatically detected with the 333 * conventional semantics - If it begins with 0x the number will be parsed as a 334 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be 335 * parsed as an octal number. Otherwise it will be parsed as a decimal. 336 * @res: Where to write the result of the conversion on success. 337 * 338 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error. 339 * Used as a replacement for the obsolete simple_strtoull. Return code must 340 * be checked. 341 */ 342 static inline int __must_check kstrtol(const char *s, unsigned int base, long *res) 343 { 344 /* 345 * We want to shortcut function call, but 346 * __builtin_types_compatible_p(long, long long) = 0. 347 */ 348 if (sizeof(long) == sizeof(long long) && 349 __alignof__(long) == __alignof__(long long)) 350 return kstrtoll(s, base, (long long *)res); 351 else 352 return _kstrtol(s, base, res); 353 } 354 355 int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res); 356 int __must_check kstrtoint(const char *s, unsigned int base, int *res); 357 358 static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res) 359 { 360 return kstrtoull(s, base, res); 361 } 362 363 static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res) 364 { 365 return kstrtoll(s, base, res); 366 } 367 368 static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res) 369 { 370 return kstrtouint(s, base, res); 371 } 372 373 static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res) 374 { 375 return kstrtoint(s, base, res); 376 } 377 378 int __must_check kstrtou16(const char *s, unsigned int base, u16 *res); 379 int __must_check kstrtos16(const char *s, unsigned int base, s16 *res); 380 int __must_check kstrtou8(const char *s, unsigned int base, u8 *res); 381 int __must_check kstrtos8(const char *s, unsigned int base, s8 *res); 382 int __must_check kstrtobool(const char *s, bool *res); 383 384 int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res); 385 int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res); 386 int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res); 387 int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res); 388 int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res); 389 int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res); 390 int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res); 391 int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res); 392 int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res); 393 int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res); 394 int __must_check kstrtobool_from_user(const char __user *s, size_t count, bool *res); 395 396 static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res) 397 { 398 return kstrtoull_from_user(s, count, base, res); 399 } 400 401 static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res) 402 { 403 return kstrtoll_from_user(s, count, base, res); 404 } 405 406 static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res) 407 { 408 return kstrtouint_from_user(s, count, base, res); 409 } 410 411 static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res) 412 { 413 return kstrtoint_from_user(s, count, base, res); 414 } 415 416 /* Obsolete, do not use. Use kstrto<foo> instead */ 417 418 extern unsigned long simple_strtoul(const char *,char **,unsigned int); 419 extern long simple_strtol(const char *,char **,unsigned int); 420 extern unsigned long long simple_strtoull(const char *,char **,unsigned int); 421 extern long long simple_strtoll(const char *,char **,unsigned int); 422 423 extern int num_to_str(char *buf, int size, unsigned long long num); 424 425 /* lib/printf utilities */ 426 427 extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...); 428 extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list); 429 extern __printf(3, 4) 430 int snprintf(char *buf, size_t size, const char *fmt, ...); 431 extern __printf(3, 0) 432 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args); 433 extern __printf(3, 4) 434 int scnprintf(char *buf, size_t size, const char *fmt, ...); 435 extern __printf(3, 0) 436 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args); 437 extern __printf(2, 3) __malloc 438 char *kasprintf(gfp_t gfp, const char *fmt, ...); 439 extern __printf(2, 0) __malloc 440 char *kvasprintf(gfp_t gfp, const char *fmt, va_list args); 441 extern __printf(2, 0) 442 const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list args); 443 444 extern __scanf(2, 3) 445 int sscanf(const char *, const char *, ...); 446 extern __scanf(2, 0) 447 int vsscanf(const char *, const char *, va_list); 448 449 extern int get_option(char **str, int *pint); 450 extern char *get_options(const char *str, int nints, int *ints); 451 extern unsigned long long memparse(const char *ptr, char **retptr); 452 extern bool parse_option_str(const char *str, const char *option); 453 extern char *next_arg(char *args, char **param, char **val); 454 455 extern int core_kernel_text(unsigned long addr); 456 extern int core_kernel_data(unsigned long addr); 457 extern int __kernel_text_address(unsigned long addr); 458 extern int kernel_text_address(unsigned long addr); 459 extern int func_ptr_is_kernel_text(void *ptr); 460 461 unsigned long int_sqrt(unsigned long); 462 463 extern void bust_spinlocks(int yes); 464 extern int oops_in_progress; /* If set, an oops, panic(), BUG() or die() is in progress */ 465 extern int panic_timeout; 466 extern int panic_on_oops; 467 extern int panic_on_unrecovered_nmi; 468 extern int panic_on_io_nmi; 469 extern int panic_on_warn; 470 extern int sysctl_panic_on_rcu_stall; 471 extern int sysctl_panic_on_stackoverflow; 472 473 extern bool crash_kexec_post_notifiers; 474 475 /* 476 * panic_cpu is used for synchronizing panic() and crash_kexec() execution. It 477 * holds a CPU number which is executing panic() currently. A value of 478 * PANIC_CPU_INVALID means no CPU has entered panic() or crash_kexec(). 479 */ 480 extern atomic_t panic_cpu; 481 #define PANIC_CPU_INVALID -1 482 483 /* 484 * Only to be used by arch init code. If the user over-wrote the default 485 * CONFIG_PANIC_TIMEOUT, honor it. 486 */ 487 static inline void set_arch_panic_timeout(int timeout, int arch_default_timeout) 488 { 489 if (panic_timeout == arch_default_timeout) 490 panic_timeout = timeout; 491 } 492 extern const char *print_tainted(void); 493 enum lockdep_ok { 494 LOCKDEP_STILL_OK, 495 LOCKDEP_NOW_UNRELIABLE 496 }; 497 extern void add_taint(unsigned flag, enum lockdep_ok); 498 extern int test_taint(unsigned flag); 499 extern unsigned long get_taint(void); 500 extern int root_mountflags; 501 502 extern bool early_boot_irqs_disabled; 503 504 /* 505 * Values used for system_state. Ordering of the states must not be changed 506 * as code checks for <, <=, >, >= STATE. 507 */ 508 extern enum system_states { 509 SYSTEM_BOOTING, 510 SYSTEM_SCHEDULING, 511 SYSTEM_RUNNING, 512 SYSTEM_HALT, 513 SYSTEM_POWER_OFF, 514 SYSTEM_RESTART, 515 } system_state; 516 517 #define TAINT_PROPRIETARY_MODULE 0 518 #define TAINT_FORCED_MODULE 1 519 #define TAINT_CPU_OUT_OF_SPEC 2 520 #define TAINT_FORCED_RMMOD 3 521 #define TAINT_MACHINE_CHECK 4 522 #define TAINT_BAD_PAGE 5 523 #define TAINT_USER 6 524 #define TAINT_DIE 7 525 #define TAINT_OVERRIDDEN_ACPI_TABLE 8 526 #define TAINT_WARN 9 527 #define TAINT_CRAP 10 528 #define TAINT_FIRMWARE_WORKAROUND 11 529 #define TAINT_OOT_MODULE 12 530 #define TAINT_UNSIGNED_MODULE 13 531 #define TAINT_SOFTLOCKUP 14 532 #define TAINT_LIVEPATCH 15 533 #define TAINT_FLAGS_COUNT 16 534 535 struct taint_flag { 536 char c_true; /* character printed when tainted */ 537 char c_false; /* character printed when not tainted */ 538 bool module; /* also show as a per-module taint flag */ 539 }; 540 541 extern const struct taint_flag taint_flags[TAINT_FLAGS_COUNT]; 542 543 extern const char hex_asc[]; 544 #define hex_asc_lo(x) hex_asc[((x) & 0x0f)] 545 #define hex_asc_hi(x) hex_asc[((x) & 0xf0) >> 4] 546 547 static inline char *hex_byte_pack(char *buf, u8 byte) 548 { 549 *buf++ = hex_asc_hi(byte); 550 *buf++ = hex_asc_lo(byte); 551 return buf; 552 } 553 554 extern const char hex_asc_upper[]; 555 #define hex_asc_upper_lo(x) hex_asc_upper[((x) & 0x0f)] 556 #define hex_asc_upper_hi(x) hex_asc_upper[((x) & 0xf0) >> 4] 557 558 static inline char *hex_byte_pack_upper(char *buf, u8 byte) 559 { 560 *buf++ = hex_asc_upper_hi(byte); 561 *buf++ = hex_asc_upper_lo(byte); 562 return buf; 563 } 564 565 extern int hex_to_bin(char ch); 566 extern int __must_check hex2bin(u8 *dst, const char *src, size_t count); 567 extern char *bin2hex(char *dst, const void *src, size_t count); 568 569 bool mac_pton(const char *s, u8 *mac); 570 571 /* 572 * General tracing related utility functions - trace_printk(), 573 * tracing_on/tracing_off and tracing_start()/tracing_stop 574 * 575 * Use tracing_on/tracing_off when you want to quickly turn on or off 576 * tracing. It simply enables or disables the recording of the trace events. 577 * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on 578 * file, which gives a means for the kernel and userspace to interact. 579 * Place a tracing_off() in the kernel where you want tracing to end. 580 * From user space, examine the trace, and then echo 1 > tracing_on 581 * to continue tracing. 582 * 583 * tracing_stop/tracing_start has slightly more overhead. It is used 584 * by things like suspend to ram where disabling the recording of the 585 * trace is not enough, but tracing must actually stop because things 586 * like calling smp_processor_id() may crash the system. 587 * 588 * Most likely, you want to use tracing_on/tracing_off. 589 */ 590 591 enum ftrace_dump_mode { 592 DUMP_NONE, 593 DUMP_ALL, 594 DUMP_ORIG, 595 }; 596 597 #ifdef CONFIG_TRACING 598 void tracing_on(void); 599 void tracing_off(void); 600 int tracing_is_on(void); 601 void tracing_snapshot(void); 602 void tracing_snapshot_alloc(void); 603 604 extern void tracing_start(void); 605 extern void tracing_stop(void); 606 607 static inline __printf(1, 2) 608 void ____trace_printk_check_format(const char *fmt, ...) 609 { 610 } 611 #define __trace_printk_check_format(fmt, args...) \ 612 do { \ 613 if (0) \ 614 ____trace_printk_check_format(fmt, ##args); \ 615 } while (0) 616 617 /** 618 * trace_printk - printf formatting in the ftrace buffer 619 * @fmt: the printf format for printing 620 * 621 * Note: __trace_printk is an internal function for trace_printk and 622 * the @ip is passed in via the trace_printk macro. 623 * 624 * This function allows a kernel developer to debug fast path sections 625 * that printk is not appropriate for. By scattering in various 626 * printk like tracing in the code, a developer can quickly see 627 * where problems are occurring. 628 * 629 * This is intended as a debugging tool for the developer only. 630 * Please refrain from leaving trace_printks scattered around in 631 * your code. (Extra memory is used for special buffers that are 632 * allocated when trace_printk() is used) 633 * 634 * A little optization trick is done here. If there's only one 635 * argument, there's no need to scan the string for printf formats. 636 * The trace_puts() will suffice. But how can we take advantage of 637 * using trace_puts() when trace_printk() has only one argument? 638 * By stringifying the args and checking the size we can tell 639 * whether or not there are args. __stringify((__VA_ARGS__)) will 640 * turn into "()\0" with a size of 3 when there are no args, anything 641 * else will be bigger. All we need to do is define a string to this, 642 * and then take its size and compare to 3. If it's bigger, use 643 * do_trace_printk() otherwise, optimize it to trace_puts(). Then just 644 * let gcc optimize the rest. 645 */ 646 647 #define trace_printk(fmt, ...) \ 648 do { \ 649 char _______STR[] = __stringify((__VA_ARGS__)); \ 650 if (sizeof(_______STR) > 3) \ 651 do_trace_printk(fmt, ##__VA_ARGS__); \ 652 else \ 653 trace_puts(fmt); \ 654 } while (0) 655 656 #define do_trace_printk(fmt, args...) \ 657 do { \ 658 static const char *trace_printk_fmt __used \ 659 __attribute__((section("__trace_printk_fmt"))) = \ 660 __builtin_constant_p(fmt) ? fmt : NULL; \ 661 \ 662 __trace_printk_check_format(fmt, ##args); \ 663 \ 664 if (__builtin_constant_p(fmt)) \ 665 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \ 666 else \ 667 __trace_printk(_THIS_IP_, fmt, ##args); \ 668 } while (0) 669 670 extern __printf(2, 3) 671 int __trace_bprintk(unsigned long ip, const char *fmt, ...); 672 673 extern __printf(2, 3) 674 int __trace_printk(unsigned long ip, const char *fmt, ...); 675 676 /** 677 * trace_puts - write a string into the ftrace buffer 678 * @str: the string to record 679 * 680 * Note: __trace_bputs is an internal function for trace_puts and 681 * the @ip is passed in via the trace_puts macro. 682 * 683 * This is similar to trace_printk() but is made for those really fast 684 * paths that a developer wants the least amount of "Heisenbug" affects, 685 * where the processing of the print format is still too much. 686 * 687 * This function allows a kernel developer to debug fast path sections 688 * that printk is not appropriate for. By scattering in various 689 * printk like tracing in the code, a developer can quickly see 690 * where problems are occurring. 691 * 692 * This is intended as a debugging tool for the developer only. 693 * Please refrain from leaving trace_puts scattered around in 694 * your code. (Extra memory is used for special buffers that are 695 * allocated when trace_puts() is used) 696 * 697 * Returns: 0 if nothing was written, positive # if string was. 698 * (1 when __trace_bputs is used, strlen(str) when __trace_puts is used) 699 */ 700 701 #define trace_puts(str) ({ \ 702 static const char *trace_printk_fmt __used \ 703 __attribute__((section("__trace_printk_fmt"))) = \ 704 __builtin_constant_p(str) ? str : NULL; \ 705 \ 706 if (__builtin_constant_p(str)) \ 707 __trace_bputs(_THIS_IP_, trace_printk_fmt); \ 708 else \ 709 __trace_puts(_THIS_IP_, str, strlen(str)); \ 710 }) 711 extern int __trace_bputs(unsigned long ip, const char *str); 712 extern int __trace_puts(unsigned long ip, const char *str, int size); 713 714 extern void trace_dump_stack(int skip); 715 716 /* 717 * The double __builtin_constant_p is because gcc will give us an error 718 * if we try to allocate the static variable to fmt if it is not a 719 * constant. Even with the outer if statement. 720 */ 721 #define ftrace_vprintk(fmt, vargs) \ 722 do { \ 723 if (__builtin_constant_p(fmt)) { \ 724 static const char *trace_printk_fmt __used \ 725 __attribute__((section("__trace_printk_fmt"))) = \ 726 __builtin_constant_p(fmt) ? fmt : NULL; \ 727 \ 728 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs); \ 729 } else \ 730 __ftrace_vprintk(_THIS_IP_, fmt, vargs); \ 731 } while (0) 732 733 extern __printf(2, 0) int 734 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap); 735 736 extern __printf(2, 0) int 737 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap); 738 739 extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode); 740 #else 741 static inline void tracing_start(void) { } 742 static inline void tracing_stop(void) { } 743 static inline void trace_dump_stack(int skip) { } 744 745 static inline void tracing_on(void) { } 746 static inline void tracing_off(void) { } 747 static inline int tracing_is_on(void) { return 0; } 748 static inline void tracing_snapshot(void) { } 749 static inline void tracing_snapshot_alloc(void) { } 750 751 static inline __printf(1, 2) 752 int trace_printk(const char *fmt, ...) 753 { 754 return 0; 755 } 756 static __printf(1, 0) inline int 757 ftrace_vprintk(const char *fmt, va_list ap) 758 { 759 return 0; 760 } 761 static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { } 762 #endif /* CONFIG_TRACING */ 763 764 /* 765 * min()/max()/clamp() macros that also do 766 * strict type-checking.. See the 767 * "unnecessary" pointer comparison. 768 */ 769 #define __min(t1, t2, min1, min2, x, y) ({ \ 770 t1 min1 = (x); \ 771 t2 min2 = (y); \ 772 (void) (&min1 == &min2); \ 773 min1 < min2 ? min1 : min2; }) 774 #define min(x, y) \ 775 __min(typeof(x), typeof(y), \ 776 __UNIQUE_ID(min1_), __UNIQUE_ID(min2_), \ 777 x, y) 778 779 #define __max(t1, t2, max1, max2, x, y) ({ \ 780 t1 max1 = (x); \ 781 t2 max2 = (y); \ 782 (void) (&max1 == &max2); \ 783 max1 > max2 ? max1 : max2; }) 784 #define max(x, y) \ 785 __max(typeof(x), typeof(y), \ 786 __UNIQUE_ID(max1_), __UNIQUE_ID(max2_), \ 787 x, y) 788 789 #define min3(x, y, z) min((typeof(x))min(x, y), z) 790 #define max3(x, y, z) max((typeof(x))max(x, y), z) 791 792 /** 793 * min_not_zero - return the minimum that is _not_ zero, unless both are zero 794 * @x: value1 795 * @y: value2 796 */ 797 #define min_not_zero(x, y) ({ \ 798 typeof(x) __x = (x); \ 799 typeof(y) __y = (y); \ 800 __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); }) 801 802 /** 803 * clamp - return a value clamped to a given range with strict typechecking 804 * @val: current value 805 * @lo: lowest allowable value 806 * @hi: highest allowable value 807 * 808 * This macro does strict typechecking of lo/hi to make sure they are of the 809 * same type as val. See the unnecessary pointer comparisons. 810 */ 811 #define clamp(val, lo, hi) min((typeof(val))max(val, lo), hi) 812 813 /* 814 * ..and if you can't take the strict 815 * types, you can specify one yourself. 816 * 817 * Or not use min/max/clamp at all, of course. 818 */ 819 #define min_t(type, x, y) \ 820 __min(type, type, \ 821 __UNIQUE_ID(min1_), __UNIQUE_ID(min2_), \ 822 x, y) 823 824 #define max_t(type, x, y) \ 825 __max(type, type, \ 826 __UNIQUE_ID(min1_), __UNIQUE_ID(min2_), \ 827 x, y) 828 829 /** 830 * clamp_t - return a value clamped to a given range using a given type 831 * @type: the type of variable to use 832 * @val: current value 833 * @lo: minimum allowable value 834 * @hi: maximum allowable value 835 * 836 * This macro does no typechecking and uses temporary variables of type 837 * 'type' to make all the comparisons. 838 */ 839 #define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi) 840 841 /** 842 * clamp_val - return a value clamped to a given range using val's type 843 * @val: current value 844 * @lo: minimum allowable value 845 * @hi: maximum allowable value 846 * 847 * This macro does no typechecking and uses temporary variables of whatever 848 * type the input argument 'val' is. This is useful when val is an unsigned 849 * type and min and max are literals that will otherwise be assigned a signed 850 * integer type. 851 */ 852 #define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi) 853 854 855 /* 856 * swap - swap value of @a and @b 857 */ 858 #define swap(a, b) \ 859 do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0) 860 861 /** 862 * container_of - cast a member of a structure out to the containing structure 863 * @ptr: the pointer to the member. 864 * @type: the type of the container struct this is embedded in. 865 * @member: the name of the member within the struct. 866 * 867 */ 868 #define container_of(ptr, type, member) ({ \ 869 void *__mptr = (void *)(ptr); \ 870 BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \ 871 !__same_type(*(ptr), void), \ 872 "pointer type mismatch in container_of()"); \ 873 ((type *)(__mptr - offsetof(type, member))); }) 874 875 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */ 876 #ifdef CONFIG_FTRACE_MCOUNT_RECORD 877 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD 878 #endif 879 880 /* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */ 881 #define VERIFY_OCTAL_PERMISSIONS(perms) \ 882 (BUILD_BUG_ON_ZERO((perms) < 0) + \ 883 BUILD_BUG_ON_ZERO((perms) > 0777) + \ 884 /* USER_READABLE >= GROUP_READABLE >= OTHER_READABLE */ \ 885 BUILD_BUG_ON_ZERO((((perms) >> 6) & 4) < (((perms) >> 3) & 4)) + \ 886 BUILD_BUG_ON_ZERO((((perms) >> 3) & 4) < ((perms) & 4)) + \ 887 /* USER_WRITABLE >= GROUP_WRITABLE */ \ 888 BUILD_BUG_ON_ZERO((((perms) >> 6) & 2) < (((perms) >> 3) & 2)) + \ 889 /* OTHER_WRITABLE? Generally considered a bad idea. */ \ 890 BUILD_BUG_ON_ZERO((perms) & 2) + \ 891 (perms)) 892 #endif 893