kernel.h 29 KB

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