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