kernel.h 21 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 <linux/dynamic_debug.h>
  13. #include <asm/byteorder.h>
  14. #include <uapi/linux/kernel.h>
  15. #define USHRT_MAX ((u16)(~0U))
  16. #define SHRT_MAX ((s16)(USHRT_MAX>>1))
  17. #define SHRT_MIN ((s16)(-SHRT_MAX - 1))
  18. #define INT_MAX ((int)(~0U>>1))
  19. #define INT_MIN (-INT_MAX - 1)
  20. #define UINT_MAX (~0U)
  21. #define LONG_MAX ((long)(~0UL>>1))
  22. #define LONG_MIN (-LONG_MAX - 1)
  23. #define ULONG_MAX (~0UL)
  24. #define LLONG_MAX ((long long)(~0ULL>>1))
  25. #define LLONG_MIN (-LLONG_MAX - 1)
  26. #define ULLONG_MAX (~0ULL)
  27. #define SIZE_MAX (~(size_t)0)
  28. #define STACK_MAGIC 0xdeadbeef
  29. #define REPEAT_BYTE(x) ((~0ul / 0xff) * (x))
  30. #define ALIGN(x, a) __ALIGN_KERNEL((x), (a))
  31. #define __ALIGN_MASK(x, mask) __ALIGN_KERNEL_MASK((x), (mask))
  32. #define PTR_ALIGN(p, a) ((typeof(p))ALIGN((unsigned long)(p), (a)))
  33. #define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0)
  34. #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
  35. /*
  36. * This looks more complex than it should be. But we need to
  37. * get the type for the ~ right in round_down (it needs to be
  38. * as wide as the result!), and we want to evaluate the macro
  39. * arguments just once each.
  40. */
  41. #define __round_mask(x, y) ((__typeof__(x))((y)-1))
  42. #define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
  43. #define round_down(x, y) ((x) & ~__round_mask(x, y))
  44. #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
  45. #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
  46. #define DIV_ROUND_UP_ULL(ll,d) \
  47. ({ unsigned long long _tmp = (ll)+(d)-1; do_div(_tmp, d); _tmp; })
  48. #if BITS_PER_LONG == 32
  49. # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d)
  50. #else
  51. # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d)
  52. #endif
  53. /* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */
  54. #define roundup(x, y) ( \
  55. { \
  56. const typeof(y) __y = y; \
  57. (((x) + (__y - 1)) / __y) * __y; \
  58. } \
  59. )
  60. #define rounddown(x, y) ( \
  61. { \
  62. typeof(x) __x = (x); \
  63. __x - (__x % (y)); \
  64. } \
  65. )
  66. /*
  67. * Divide positive or negative dividend by positive divisor and round
  68. * to closest integer. Result is undefined for negative divisors.
  69. */
  70. #define DIV_ROUND_CLOSEST(x, divisor)( \
  71. { \
  72. typeof(x) __x = x; \
  73. typeof(divisor) __d = divisor; \
  74. (((typeof(x))-1) > 0 || (__x) > 0) ? \
  75. (((__x) + ((__d) / 2)) / (__d)) : \
  76. (((__x) - ((__d) / 2)) / (__d)); \
  77. } \
  78. )
  79. /*
  80. * Multiplies an integer by a fraction, while avoiding unnecessary
  81. * overflow or loss of precision.
  82. */
  83. #define mult_frac(x, numer, denom)( \
  84. { \
  85. typeof(x) quot = (x) / (denom); \
  86. typeof(x) rem = (x) % (denom); \
  87. (quot * (numer)) + ((rem * (numer)) / (denom)); \
  88. } \
  89. )
  90. #define _RET_IP_ (unsigned long)__builtin_return_address(0)
  91. #define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; })
  92. #ifdef CONFIG_LBDAF
  93. # include <asm/div64.h>
  94. # define sector_div(a, b) do_div(a, b)
  95. #else
  96. # define sector_div(n, b)( \
  97. { \
  98. int _res; \
  99. _res = (n) % (b); \
  100. (n) /= (b); \
  101. _res; \
  102. } \
  103. )
  104. #endif
  105. /**
  106. * upper_32_bits - return bits 32-63 of a number
  107. * @n: the number we're accessing
  108. *
  109. * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress
  110. * the "right shift count >= width of type" warning when that quantity is
  111. * 32-bits.
  112. */
  113. #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
  114. /**
  115. * lower_32_bits - return bits 0-31 of a number
  116. * @n: the number we're accessing
  117. */
  118. #define lower_32_bits(n) ((u32)(n))
  119. struct completion;
  120. struct pt_regs;
  121. struct user;
  122. #ifdef CONFIG_PREEMPT_VOLUNTARY
  123. extern int _cond_resched(void);
  124. # define might_resched() _cond_resched()
  125. #else
  126. # define might_resched() do { } while (0)
  127. #endif
  128. #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
  129. void __might_sleep(const char *file, int line, int preempt_offset);
  130. /**
  131. * might_sleep - annotation for functions that can sleep
  132. *
  133. * this macro will print a stack trace if it is executed in an atomic
  134. * context (spinlock, irq-handler, ...).
  135. *
  136. * This is a useful debugging help to be able to catch problems early and not
  137. * be bitten later when the calling function happens to sleep when it is not
  138. * supposed to.
  139. */
  140. # define might_sleep() \
  141. do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
  142. #else
  143. static inline void __might_sleep(const char *file, int line,
  144. int preempt_offset) { }
  145. # define might_sleep() do { might_resched(); } while (0)
  146. #endif
  147. #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
  148. /*
  149. * abs() handles unsigned and signed longs, ints, shorts and chars. For all
  150. * input types abs() returns a signed long.
  151. * abs() should not be used for 64-bit types (s64, u64, long long) - use abs64()
  152. * for those.
  153. */
  154. #define abs(x) ({ \
  155. long ret; \
  156. if (sizeof(x) == sizeof(long)) { \
  157. long __x = (x); \
  158. ret = (__x < 0) ? -__x : __x; \
  159. } else { \
  160. int __x = (x); \
  161. ret = (__x < 0) ? -__x : __x; \
  162. } \
  163. ret; \
  164. })
  165. #define abs64(x) ({ \
  166. s64 __x = (x); \
  167. (__x < 0) ? -__x : __x; \
  168. })
  169. #ifdef CONFIG_PROVE_LOCKING
  170. void might_fault(void);
  171. #else
  172. static inline void might_fault(void)
  173. {
  174. might_sleep();
  175. }
  176. #endif
  177. extern struct atomic_notifier_head panic_notifier_list;
  178. extern long (*panic_blink)(int state);
  179. __printf(1, 2)
  180. void panic(const char *fmt, ...)
  181. __noreturn __cold;
  182. extern void oops_enter(void);
  183. extern void oops_exit(void);
  184. void print_oops_end_marker(void);
  185. extern int oops_may_print(void);
  186. void do_exit(long error_code)
  187. __noreturn;
  188. void complete_and_exit(struct completion *, long)
  189. __noreturn;
  190. /* Internal, do not use. */
  191. int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
  192. int __must_check _kstrtol(const char *s, unsigned int base, long *res);
  193. int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
  194. int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
  195. static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
  196. {
  197. /*
  198. * We want to shortcut function call, but
  199. * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
  200. */
  201. if (sizeof(unsigned long) == sizeof(unsigned long long) &&
  202. __alignof__(unsigned long) == __alignof__(unsigned long long))
  203. return kstrtoull(s, base, (unsigned long long *)res);
  204. else
  205. return _kstrtoul(s, base, res);
  206. }
  207. static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
  208. {
  209. /*
  210. * We want to shortcut function call, but
  211. * __builtin_types_compatible_p(long, long long) = 0.
  212. */
  213. if (sizeof(long) == sizeof(long long) &&
  214. __alignof__(long) == __alignof__(long long))
  215. return kstrtoll(s, base, (long long *)res);
  216. else
  217. return _kstrtol(s, base, res);
  218. }
  219. int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
  220. int __must_check kstrtoint(const char *s, unsigned int base, int *res);
  221. static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
  222. {
  223. return kstrtoull(s, base, res);
  224. }
  225. static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
  226. {
  227. return kstrtoll(s, base, res);
  228. }
  229. static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
  230. {
  231. return kstrtouint(s, base, res);
  232. }
  233. static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
  234. {
  235. return kstrtoint(s, base, res);
  236. }
  237. int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
  238. int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
  239. int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
  240. int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
  241. int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
  242. int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
  243. int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
  244. int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
  245. int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
  246. int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
  247. int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
  248. int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
  249. int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
  250. int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
  251. static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
  252. {
  253. return kstrtoull_from_user(s, count, base, res);
  254. }
  255. static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
  256. {
  257. return kstrtoll_from_user(s, count, base, res);
  258. }
  259. static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
  260. {
  261. return kstrtouint_from_user(s, count, base, res);
  262. }
  263. static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
  264. {
  265. return kstrtoint_from_user(s, count, base, res);
  266. }
  267. /* Obsolete, do not use. Use kstrto<foo> instead */
  268. extern unsigned long simple_strtoul(const char *,char **,unsigned int);
  269. extern long simple_strtol(const char *,char **,unsigned int);
  270. extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
  271. extern long long simple_strtoll(const char *,char **,unsigned int);
  272. #define strict_strtoul kstrtoul
  273. #define strict_strtol kstrtol
  274. #define strict_strtoull kstrtoull
  275. #define strict_strtoll kstrtoll
  276. extern int num_to_str(char *buf, int size, unsigned long long num);
  277. /* lib/printf utilities */
  278. extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
  279. extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
  280. extern __printf(3, 4)
  281. int snprintf(char *buf, size_t size, const char *fmt, ...);
  282. extern __printf(3, 0)
  283. int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
  284. extern __printf(3, 4)
  285. int scnprintf(char *buf, size_t size, const char *fmt, ...);
  286. extern __printf(3, 0)
  287. int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
  288. extern __printf(2, 3)
  289. char *kasprintf(gfp_t gfp, const char *fmt, ...);
  290. extern char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
  291. extern __scanf(2, 3)
  292. int sscanf(const char *, const char *, ...);
  293. extern __scanf(2, 0)
  294. int vsscanf(const char *, const char *, va_list);
  295. extern int get_option(char **str, int *pint);
  296. extern char *get_options(const char *str, int nints, int *ints);
  297. extern unsigned long long memparse(const char *ptr, char **retptr);
  298. extern int core_kernel_text(unsigned long addr);
  299. extern int core_kernel_data(unsigned long addr);
  300. extern int __kernel_text_address(unsigned long addr);
  301. extern int kernel_text_address(unsigned long addr);
  302. extern int func_ptr_is_kernel_text(void *ptr);
  303. struct pid;
  304. extern struct pid *session_of_pgrp(struct pid *pgrp);
  305. unsigned long int_sqrt(unsigned long);
  306. extern void bust_spinlocks(int yes);
  307. extern void wake_up_klogd(void);
  308. extern int oops_in_progress; /* If set, an oops, panic(), BUG() or die() is in progress */
  309. extern int panic_timeout;
  310. extern int panic_on_oops;
  311. extern int panic_on_unrecovered_nmi;
  312. extern int panic_on_io_nmi;
  313. extern int sysctl_panic_on_stackoverflow;
  314. extern const char *print_tainted(void);
  315. extern void add_taint(unsigned flag);
  316. extern int test_taint(unsigned flag);
  317. extern unsigned long get_taint(void);
  318. extern int root_mountflags;
  319. extern bool early_boot_irqs_disabled;
  320. /* Values used for system_state */
  321. extern enum system_states {
  322. SYSTEM_BOOTING,
  323. SYSTEM_RUNNING,
  324. SYSTEM_HALT,
  325. SYSTEM_POWER_OFF,
  326. SYSTEM_RESTART,
  327. } system_state;
  328. #define TAINT_PROPRIETARY_MODULE 0
  329. #define TAINT_FORCED_MODULE 1
  330. #define TAINT_UNSAFE_SMP 2
  331. #define TAINT_FORCED_RMMOD 3
  332. #define TAINT_MACHINE_CHECK 4
  333. #define TAINT_BAD_PAGE 5
  334. #define TAINT_USER 6
  335. #define TAINT_DIE 7
  336. #define TAINT_OVERRIDDEN_ACPI_TABLE 8
  337. #define TAINT_WARN 9
  338. #define TAINT_CRAP 10
  339. #define TAINT_FIRMWARE_WORKAROUND 11
  340. #define TAINT_OOT_MODULE 12
  341. extern const char hex_asc[];
  342. #define hex_asc_lo(x) hex_asc[((x) & 0x0f)]
  343. #define hex_asc_hi(x) hex_asc[((x) & 0xf0) >> 4]
  344. static inline char *hex_byte_pack(char *buf, u8 byte)
  345. {
  346. *buf++ = hex_asc_hi(byte);
  347. *buf++ = hex_asc_lo(byte);
  348. return buf;
  349. }
  350. static inline char * __deprecated pack_hex_byte(char *buf, u8 byte)
  351. {
  352. return hex_byte_pack(buf, byte);
  353. }
  354. extern int hex_to_bin(char ch);
  355. extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
  356. /*
  357. * General tracing related utility functions - trace_printk(),
  358. * tracing_on/tracing_off and tracing_start()/tracing_stop
  359. *
  360. * Use tracing_on/tracing_off when you want to quickly turn on or off
  361. * tracing. It simply enables or disables the recording of the trace events.
  362. * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
  363. * file, which gives a means for the kernel and userspace to interact.
  364. * Place a tracing_off() in the kernel where you want tracing to end.
  365. * From user space, examine the trace, and then echo 1 > tracing_on
  366. * to continue tracing.
  367. *
  368. * tracing_stop/tracing_start has slightly more overhead. It is used
  369. * by things like suspend to ram where disabling the recording of the
  370. * trace is not enough, but tracing must actually stop because things
  371. * like calling smp_processor_id() may crash the system.
  372. *
  373. * Most likely, you want to use tracing_on/tracing_off.
  374. */
  375. #ifdef CONFIG_RING_BUFFER
  376. /* trace_off_permanent stops recording with no way to bring it back */
  377. void tracing_off_permanent(void);
  378. #else
  379. static inline void tracing_off_permanent(void) { }
  380. #endif
  381. enum ftrace_dump_mode {
  382. DUMP_NONE,
  383. DUMP_ALL,
  384. DUMP_ORIG,
  385. };
  386. #ifdef CONFIG_TRACING
  387. void tracing_on(void);
  388. void tracing_off(void);
  389. int tracing_is_on(void);
  390. extern void tracing_start(void);
  391. extern void tracing_stop(void);
  392. extern void ftrace_off_permanent(void);
  393. static inline __printf(1, 2)
  394. void ____trace_printk_check_format(const char *fmt, ...)
  395. {
  396. }
  397. #define __trace_printk_check_format(fmt, args...) \
  398. do { \
  399. if (0) \
  400. ____trace_printk_check_format(fmt, ##args); \
  401. } while (0)
  402. /**
  403. * trace_printk - printf formatting in the ftrace buffer
  404. * @fmt: the printf format for printing
  405. *
  406. * Note: __trace_printk is an internal function for trace_printk and
  407. * the @ip is passed in via the trace_printk macro.
  408. *
  409. * This function allows a kernel developer to debug fast path sections
  410. * that printk is not appropriate for. By scattering in various
  411. * printk like tracing in the code, a developer can quickly see
  412. * where problems are occurring.
  413. *
  414. * This is intended as a debugging tool for the developer only.
  415. * Please refrain from leaving trace_printks scattered around in
  416. * your code.
  417. */
  418. #define trace_printk(fmt, args...) \
  419. do { \
  420. static const char *trace_printk_fmt \
  421. __attribute__((section("__trace_printk_fmt"))) = \
  422. __builtin_constant_p(fmt) ? fmt : NULL; \
  423. \
  424. __trace_printk_check_format(fmt, ##args); \
  425. \
  426. if (__builtin_constant_p(fmt)) \
  427. __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \
  428. else \
  429. __trace_printk(_THIS_IP_, fmt, ##args); \
  430. } while (0)
  431. extern __printf(2, 3)
  432. int __trace_bprintk(unsigned long ip, const char *fmt, ...);
  433. extern __printf(2, 3)
  434. int __trace_printk(unsigned long ip, const char *fmt, ...);
  435. extern void trace_dump_stack(void);
  436. /*
  437. * The double __builtin_constant_p is because gcc will give us an error
  438. * if we try to allocate the static variable to fmt if it is not a
  439. * constant. Even with the outer if statement.
  440. */
  441. #define ftrace_vprintk(fmt, vargs) \
  442. do { \
  443. if (__builtin_constant_p(fmt)) { \
  444. static const char *trace_printk_fmt \
  445. __attribute__((section("__trace_printk_fmt"))) = \
  446. __builtin_constant_p(fmt) ? fmt : NULL; \
  447. \
  448. __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs); \
  449. } else \
  450. __ftrace_vprintk(_THIS_IP_, fmt, vargs); \
  451. } while (0)
  452. extern int
  453. __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
  454. extern int
  455. __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
  456. extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
  457. #else
  458. static inline __printf(1, 2)
  459. int trace_printk(const char *fmt, ...);
  460. static inline void tracing_start(void) { }
  461. static inline void tracing_stop(void) { }
  462. static inline void ftrace_off_permanent(void) { }
  463. static inline void trace_dump_stack(void) { }
  464. static inline void tracing_on(void) { }
  465. static inline void tracing_off(void) { }
  466. static inline int tracing_is_on(void) { return 0; }
  467. static inline int
  468. trace_printk(const char *fmt, ...)
  469. {
  470. return 0;
  471. }
  472. static inline int
  473. ftrace_vprintk(const char *fmt, va_list ap)
  474. {
  475. return 0;
  476. }
  477. static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
  478. #endif /* CONFIG_TRACING */
  479. /*
  480. * min()/max()/clamp() macros that also do
  481. * strict type-checking.. See the
  482. * "unnecessary" pointer comparison.
  483. */
  484. #define min(x, y) ({ \
  485. typeof(x) _min1 = (x); \
  486. typeof(y) _min2 = (y); \
  487. (void) (&_min1 == &_min2); \
  488. _min1 < _min2 ? _min1 : _min2; })
  489. #define max(x, y) ({ \
  490. typeof(x) _max1 = (x); \
  491. typeof(y) _max2 = (y); \
  492. (void) (&_max1 == &_max2); \
  493. _max1 > _max2 ? _max1 : _max2; })
  494. #define min3(x, y, z) ({ \
  495. typeof(x) _min1 = (x); \
  496. typeof(y) _min2 = (y); \
  497. typeof(z) _min3 = (z); \
  498. (void) (&_min1 == &_min2); \
  499. (void) (&_min1 == &_min3); \
  500. _min1 < _min2 ? (_min1 < _min3 ? _min1 : _min3) : \
  501. (_min2 < _min3 ? _min2 : _min3); })
  502. #define max3(x, y, z) ({ \
  503. typeof(x) _max1 = (x); \
  504. typeof(y) _max2 = (y); \
  505. typeof(z) _max3 = (z); \
  506. (void) (&_max1 == &_max2); \
  507. (void) (&_max1 == &_max3); \
  508. _max1 > _max2 ? (_max1 > _max3 ? _max1 : _max3) : \
  509. (_max2 > _max3 ? _max2 : _max3); })
  510. /**
  511. * min_not_zero - return the minimum that is _not_ zero, unless both are zero
  512. * @x: value1
  513. * @y: value2
  514. */
  515. #define min_not_zero(x, y) ({ \
  516. typeof(x) __x = (x); \
  517. typeof(y) __y = (y); \
  518. __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
  519. /**
  520. * clamp - return a value clamped to a given range with strict typechecking
  521. * @val: current value
  522. * @min: minimum allowable value
  523. * @max: maximum allowable value
  524. *
  525. * This macro does strict typechecking of min/max to make sure they are of the
  526. * same type as val. See the unnecessary pointer comparisons.
  527. */
  528. #define clamp(val, min, max) ({ \
  529. typeof(val) __val = (val); \
  530. typeof(min) __min = (min); \
  531. typeof(max) __max = (max); \
  532. (void) (&__val == &__min); \
  533. (void) (&__val == &__max); \
  534. __val = __val < __min ? __min: __val; \
  535. __val > __max ? __max: __val; })
  536. /*
  537. * ..and if you can't take the strict
  538. * types, you can specify one yourself.
  539. *
  540. * Or not use min/max/clamp at all, of course.
  541. */
  542. #define min_t(type, x, y) ({ \
  543. type __min1 = (x); \
  544. type __min2 = (y); \
  545. __min1 < __min2 ? __min1: __min2; })
  546. #define max_t(type, x, y) ({ \
  547. type __max1 = (x); \
  548. type __max2 = (y); \
  549. __max1 > __max2 ? __max1: __max2; })
  550. /**
  551. * clamp_t - return a value clamped to a given range using a given type
  552. * @type: the type of variable to use
  553. * @val: current value
  554. * @min: minimum allowable value
  555. * @max: maximum allowable value
  556. *
  557. * This macro does no typechecking and uses temporary variables of type
  558. * 'type' to make all the comparisons.
  559. */
  560. #define clamp_t(type, val, min, max) ({ \
  561. type __val = (val); \
  562. type __min = (min); \
  563. type __max = (max); \
  564. __val = __val < __min ? __min: __val; \
  565. __val > __max ? __max: __val; })
  566. /**
  567. * clamp_val - return a value clamped to a given range using val's type
  568. * @val: current value
  569. * @min: minimum allowable value
  570. * @max: maximum allowable value
  571. *
  572. * This macro does no typechecking and uses temporary variables of whatever
  573. * type the input argument 'val' is. This is useful when val is an unsigned
  574. * type and min and max are literals that will otherwise be assigned a signed
  575. * integer type.
  576. */
  577. #define clamp_val(val, min, max) ({ \
  578. typeof(val) __val = (val); \
  579. typeof(val) __min = (min); \
  580. typeof(val) __max = (max); \
  581. __val = __val < __min ? __min: __val; \
  582. __val > __max ? __max: __val; })
  583. /*
  584. * swap - swap value of @a and @b
  585. */
  586. #define swap(a, b) \
  587. do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
  588. /**
  589. * container_of - cast a member of a structure out to the containing structure
  590. * @ptr: the pointer to the member.
  591. * @type: the type of the container struct this is embedded in.
  592. * @member: the name of the member within the struct.
  593. *
  594. */
  595. #define container_of(ptr, type, member) ({ \
  596. const typeof( ((type *)0)->member ) *__mptr = (ptr); \
  597. (type *)( (char *)__mptr - offsetof(type,member) );})
  598. /* Trap pasters of __FUNCTION__ at compile-time */
  599. #define __FUNCTION__ (__func__)
  600. /* This helps us to avoid #ifdef CONFIG_NUMA */
  601. #ifdef CONFIG_NUMA
  602. #define NUMA_BUILD 1
  603. #else
  604. #define NUMA_BUILD 0
  605. #endif
  606. /* This helps us avoid #ifdef CONFIG_COMPACTION */
  607. #ifdef CONFIG_COMPACTION
  608. #define COMPACTION_BUILD 1
  609. #else
  610. #define COMPACTION_BUILD 0
  611. #endif
  612. /* This helps us to avoid #ifdef CONFIG_SYMBOL_PREFIX */
  613. #ifdef CONFIG_SYMBOL_PREFIX
  614. #define SYMBOL_PREFIX CONFIG_SYMBOL_PREFIX
  615. #else
  616. #define SYMBOL_PREFIX ""
  617. #endif
  618. /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
  619. #ifdef CONFIG_FTRACE_MCOUNT_RECORD
  620. # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
  621. #endif
  622. extern int do_sysinfo(struct sysinfo *info);
  623. #endif