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