kernel.h 23 KB

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  1. #ifndef _LINUX_KERNEL_H
  2. #define _LINUX_KERNEL_H
  3. #include <linux/sysinfo.h>
  4. /*
  5. * 'kernel.h' contains some often-used function prototypes etc
  6. */
  7. #define __ALIGN_KERNEL(x, a) __ALIGN_KERNEL_MASK(x, (typeof(x))(a) - 1)
  8. #define __ALIGN_KERNEL_MASK(x, mask) (((x) + (mask)) & ~(mask))
  9. #ifdef __KERNEL__
  10. #include <stdarg.h>
  11. #include <linux/linkage.h>
  12. #include <linux/stddef.h>
  13. #include <linux/types.h>
  14. #include <linux/compiler.h>
  15. #include <linux/bitops.h>
  16. #include <linux/log2.h>
  17. #include <linux/typecheck.h>
  18. #include <linux/printk.h>
  19. #include <linux/dynamic_debug.h>
  20. #include <asm/byteorder.h>
  21. #include <asm/bug.h>
  22. #define USHRT_MAX ((u16)(~0U))
  23. #define SHRT_MAX ((s16)(USHRT_MAX>>1))
  24. #define SHRT_MIN ((s16)(-SHRT_MAX - 1))
  25. #define INT_MAX ((int)(~0U>>1))
  26. #define INT_MIN (-INT_MAX - 1)
  27. #define UINT_MAX (~0U)
  28. #define LONG_MAX ((long)(~0UL>>1))
  29. #define LONG_MIN (-LONG_MAX - 1)
  30. #define ULONG_MAX (~0UL)
  31. #define LLONG_MAX ((long long)(~0ULL>>1))
  32. #define LLONG_MIN (-LLONG_MAX - 1)
  33. #define ULLONG_MAX (~0ULL)
  34. #define STACK_MAGIC 0xdeadbeef
  35. #define ALIGN(x, a) __ALIGN_KERNEL((x), (a))
  36. #define __ALIGN_MASK(x, mask) __ALIGN_KERNEL_MASK((x), (mask))
  37. #define PTR_ALIGN(p, a) ((typeof(p))ALIGN((unsigned long)(p), (a)))
  38. #define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0)
  39. #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
  40. /*
  41. * This looks more complex than it should be. But we need to
  42. * get the type for the ~ right in round_down (it needs to be
  43. * as wide as the result!), and we want to evaluate the macro
  44. * arguments just once each.
  45. */
  46. #define __round_mask(x, y) ((__typeof__(x))((y)-1))
  47. #define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
  48. #define round_down(x, y) ((x) & ~__round_mask(x, y))
  49. #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
  50. #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
  51. #define DIV_ROUND_UP_ULL(ll,d) \
  52. ({ unsigned long long _tmp = (ll)+(d)-1; do_div(_tmp, d); _tmp; })
  53. #if BITS_PER_LONG == 32
  54. # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d)
  55. #else
  56. # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d)
  57. #endif
  58. /* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */
  59. #define roundup(x, y) ( \
  60. { \
  61. const typeof(y) __y = y; \
  62. (((x) + (__y - 1)) / __y) * __y; \
  63. } \
  64. )
  65. #define rounddown(x, y) ( \
  66. { \
  67. typeof(x) __x = (x); \
  68. __x - (__x % (y)); \
  69. } \
  70. )
  71. #define DIV_ROUND_CLOSEST(x, divisor)( \
  72. { \
  73. typeof(divisor) __divisor = divisor; \
  74. (((x) + ((__divisor) / 2)) / (__divisor)); \
  75. } \
  76. )
  77. #define _RET_IP_ (unsigned long)__builtin_return_address(0)
  78. #define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; })
  79. #ifdef CONFIG_LBDAF
  80. # include <asm/div64.h>
  81. # define sector_div(a, b) do_div(a, b)
  82. #else
  83. # define sector_div(n, b)( \
  84. { \
  85. int _res; \
  86. _res = (n) % (b); \
  87. (n) /= (b); \
  88. _res; \
  89. } \
  90. )
  91. #endif
  92. /**
  93. * upper_32_bits - return bits 32-63 of a number
  94. * @n: the number we're accessing
  95. *
  96. * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress
  97. * the "right shift count >= width of type" warning when that quantity is
  98. * 32-bits.
  99. */
  100. #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
  101. /**
  102. * lower_32_bits - return bits 0-31 of a number
  103. * @n: the number we're accessing
  104. */
  105. #define lower_32_bits(n) ((u32)(n))
  106. struct completion;
  107. struct pt_regs;
  108. struct user;
  109. #ifdef CONFIG_PREEMPT_VOLUNTARY
  110. extern int _cond_resched(void);
  111. # define might_resched() _cond_resched()
  112. #else
  113. # define might_resched() do { } while (0)
  114. #endif
  115. #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
  116. void __might_sleep(const char *file, int line, int preempt_offset);
  117. /**
  118. * might_sleep - annotation for functions that can sleep
  119. *
  120. * this macro will print a stack trace if it is executed in an atomic
  121. * context (spinlock, irq-handler, ...).
  122. *
  123. * This is a useful debugging help to be able to catch problems early and not
  124. * be bitten later when the calling function happens to sleep when it is not
  125. * supposed to.
  126. */
  127. # define might_sleep() \
  128. do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
  129. #else
  130. static inline void __might_sleep(const char *file, int line,
  131. int preempt_offset) { }
  132. # define might_sleep() do { might_resched(); } while (0)
  133. #endif
  134. #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
  135. /*
  136. * abs() handles unsigned and signed longs, ints, shorts and chars. For all
  137. * input types abs() returns a signed long.
  138. * abs() should not be used for 64-bit types (s64, u64, long long) - use abs64()
  139. * for those.
  140. */
  141. #define abs(x) ({ \
  142. long ret; \
  143. if (sizeof(x) == sizeof(long)) { \
  144. long __x = (x); \
  145. ret = (__x < 0) ? -__x : __x; \
  146. } else { \
  147. int __x = (x); \
  148. ret = (__x < 0) ? -__x : __x; \
  149. } \
  150. ret; \
  151. })
  152. #define abs64(x) ({ \
  153. s64 __x = (x); \
  154. (__x < 0) ? -__x : __x; \
  155. })
  156. #ifdef CONFIG_PROVE_LOCKING
  157. void might_fault(void);
  158. #else
  159. static inline void might_fault(void)
  160. {
  161. might_sleep();
  162. }
  163. #endif
  164. extern struct atomic_notifier_head panic_notifier_list;
  165. extern long (*panic_blink)(int state);
  166. __printf(1, 2)
  167. void panic(const char *fmt, ...)
  168. __noreturn __cold;
  169. extern void oops_enter(void);
  170. extern void oops_exit(void);
  171. void print_oops_end_marker(void);
  172. extern int oops_may_print(void);
  173. void do_exit(long error_code)
  174. __noreturn;
  175. void complete_and_exit(struct completion *, long)
  176. __noreturn;
  177. /* Internal, do not use. */
  178. int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
  179. int __must_check _kstrtol(const char *s, unsigned int base, long *res);
  180. int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
  181. int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
  182. static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
  183. {
  184. /*
  185. * We want to shortcut function call, but
  186. * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
  187. */
  188. if (sizeof(unsigned long) == sizeof(unsigned long long) &&
  189. __alignof__(unsigned long) == __alignof__(unsigned long long))
  190. return kstrtoull(s, base, (unsigned long long *)res);
  191. else
  192. return _kstrtoul(s, base, res);
  193. }
  194. static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
  195. {
  196. /*
  197. * We want to shortcut function call, but
  198. * __builtin_types_compatible_p(long, long long) = 0.
  199. */
  200. if (sizeof(long) == sizeof(long long) &&
  201. __alignof__(long) == __alignof__(long long))
  202. return kstrtoll(s, base, (long long *)res);
  203. else
  204. return _kstrtol(s, base, res);
  205. }
  206. int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
  207. int __must_check kstrtoint(const char *s, unsigned int base, int *res);
  208. static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
  209. {
  210. return kstrtoull(s, base, res);
  211. }
  212. static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
  213. {
  214. return kstrtoll(s, base, res);
  215. }
  216. static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
  217. {
  218. return kstrtouint(s, base, res);
  219. }
  220. static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
  221. {
  222. return kstrtoint(s, base, res);
  223. }
  224. int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
  225. int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
  226. int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
  227. int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
  228. int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
  229. int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
  230. int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
  231. int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
  232. int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
  233. int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
  234. int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
  235. int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
  236. int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
  237. int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
  238. static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
  239. {
  240. return kstrtoull_from_user(s, count, base, res);
  241. }
  242. static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
  243. {
  244. return kstrtoll_from_user(s, count, base, res);
  245. }
  246. static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
  247. {
  248. return kstrtouint_from_user(s, count, base, res);
  249. }
  250. static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
  251. {
  252. return kstrtoint_from_user(s, count, base, res);
  253. }
  254. /* Obsolete, do not use. Use kstrto<foo> instead */
  255. extern unsigned long simple_strtoul(const char *,char **,unsigned int);
  256. extern long simple_strtol(const char *,char **,unsigned int);
  257. extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
  258. extern long long simple_strtoll(const char *,char **,unsigned int);
  259. #define strict_strtoul kstrtoul
  260. #define strict_strtol kstrtol
  261. #define strict_strtoull kstrtoull
  262. #define strict_strtoll kstrtoll
  263. /* lib/printf utilities */
  264. extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
  265. extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
  266. extern __printf(3, 4)
  267. int snprintf(char *buf, size_t size, const char *fmt, ...);
  268. extern __printf(3, 0)
  269. int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
  270. extern __printf(3, 4)
  271. int scnprintf(char *buf, size_t size, const char *fmt, ...);
  272. extern __printf(3, 0)
  273. int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
  274. extern __printf(2, 3)
  275. char *kasprintf(gfp_t gfp, const char *fmt, ...);
  276. extern char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
  277. extern int sscanf(const char *, const char *, ...)
  278. __attribute__ ((format (scanf, 2, 3)));
  279. extern int vsscanf(const char *, const char *, va_list)
  280. __attribute__ ((format (scanf, 2, 0)));
  281. extern int get_option(char **str, int *pint);
  282. extern char *get_options(const char *str, int nints, int *ints);
  283. extern unsigned long long memparse(const char *ptr, char **retptr);
  284. extern int core_kernel_text(unsigned long addr);
  285. extern int core_kernel_data(unsigned long addr);
  286. extern int __kernel_text_address(unsigned long addr);
  287. extern int kernel_text_address(unsigned long addr);
  288. extern int func_ptr_is_kernel_text(void *ptr);
  289. struct pid;
  290. extern struct pid *session_of_pgrp(struct pid *pgrp);
  291. unsigned long int_sqrt(unsigned long);
  292. extern void bust_spinlocks(int yes);
  293. extern void wake_up_klogd(void);
  294. extern int oops_in_progress; /* If set, an oops, panic(), BUG() or die() is in progress */
  295. extern int panic_timeout;
  296. extern int panic_on_oops;
  297. extern int panic_on_unrecovered_nmi;
  298. extern int panic_on_io_nmi;
  299. extern int sysctl_panic_on_stackoverflow;
  300. extern const char *print_tainted(void);
  301. extern void add_taint(unsigned flag);
  302. extern int test_taint(unsigned flag);
  303. extern unsigned long get_taint(void);
  304. extern int root_mountflags;
  305. extern bool early_boot_irqs_disabled;
  306. /* Values used for system_state */
  307. extern enum system_states {
  308. SYSTEM_BOOTING,
  309. SYSTEM_RUNNING,
  310. SYSTEM_HALT,
  311. SYSTEM_POWER_OFF,
  312. SYSTEM_RESTART,
  313. SYSTEM_SUSPEND_DISK,
  314. } system_state;
  315. #define TAINT_PROPRIETARY_MODULE 0
  316. #define TAINT_FORCED_MODULE 1
  317. #define TAINT_UNSAFE_SMP 2
  318. #define TAINT_FORCED_RMMOD 3
  319. #define TAINT_MACHINE_CHECK 4
  320. #define TAINT_BAD_PAGE 5
  321. #define TAINT_USER 6
  322. #define TAINT_DIE 7
  323. #define TAINT_OVERRIDDEN_ACPI_TABLE 8
  324. #define TAINT_WARN 9
  325. #define TAINT_CRAP 10
  326. #define TAINT_FIRMWARE_WORKAROUND 11
  327. #define TAINT_OOT_MODULE 12
  328. extern const char hex_asc[];
  329. #define hex_asc_lo(x) hex_asc[((x) & 0x0f)]
  330. #define hex_asc_hi(x) hex_asc[((x) & 0xf0) >> 4]
  331. static inline char *hex_byte_pack(char *buf, u8 byte)
  332. {
  333. *buf++ = hex_asc_hi(byte);
  334. *buf++ = hex_asc_lo(byte);
  335. return buf;
  336. }
  337. static inline char * __deprecated pack_hex_byte(char *buf, u8 byte)
  338. {
  339. return hex_byte_pack(buf, byte);
  340. }
  341. extern int hex_to_bin(char ch);
  342. extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
  343. /*
  344. * General tracing related utility functions - trace_printk(),
  345. * tracing_on/tracing_off and tracing_start()/tracing_stop
  346. *
  347. * Use tracing_on/tracing_off when you want to quickly turn on or off
  348. * tracing. It simply enables or disables the recording of the trace events.
  349. * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
  350. * file, which gives a means for the kernel and userspace to interact.
  351. * Place a tracing_off() in the kernel where you want tracing to end.
  352. * From user space, examine the trace, and then echo 1 > tracing_on
  353. * to continue tracing.
  354. *
  355. * tracing_stop/tracing_start has slightly more overhead. It is used
  356. * by things like suspend to ram where disabling the recording of the
  357. * trace is not enough, but tracing must actually stop because things
  358. * like calling smp_processor_id() may crash the system.
  359. *
  360. * Most likely, you want to use tracing_on/tracing_off.
  361. */
  362. #ifdef CONFIG_RING_BUFFER
  363. void tracing_on(void);
  364. void tracing_off(void);
  365. /* trace_off_permanent stops recording with no way to bring it back */
  366. void tracing_off_permanent(void);
  367. int tracing_is_on(void);
  368. #else
  369. static inline void tracing_on(void) { }
  370. static inline void tracing_off(void) { }
  371. static inline void tracing_off_permanent(void) { }
  372. static inline int tracing_is_on(void) { return 0; }
  373. #endif
  374. enum ftrace_dump_mode {
  375. DUMP_NONE,
  376. DUMP_ALL,
  377. DUMP_ORIG,
  378. };
  379. #ifdef CONFIG_TRACING
  380. extern void tracing_start(void);
  381. extern void tracing_stop(void);
  382. extern void ftrace_off_permanent(void);
  383. static inline __printf(1, 2)
  384. void ____trace_printk_check_format(const char *fmt, ...)
  385. {
  386. }
  387. #define __trace_printk_check_format(fmt, args...) \
  388. do { \
  389. if (0) \
  390. ____trace_printk_check_format(fmt, ##args); \
  391. } while (0)
  392. /**
  393. * trace_printk - printf formatting in the ftrace buffer
  394. * @fmt: the printf format for printing
  395. *
  396. * Note: __trace_printk is an internal function for trace_printk and
  397. * the @ip is passed in via the trace_printk macro.
  398. *
  399. * This function allows a kernel developer to debug fast path sections
  400. * that printk is not appropriate for. By scattering in various
  401. * printk like tracing in the code, a developer can quickly see
  402. * where problems are occurring.
  403. *
  404. * This is intended as a debugging tool for the developer only.
  405. * Please refrain from leaving trace_printks scattered around in
  406. * your code.
  407. */
  408. #define trace_printk(fmt, args...) \
  409. do { \
  410. __trace_printk_check_format(fmt, ##args); \
  411. if (__builtin_constant_p(fmt)) { \
  412. static const char *trace_printk_fmt \
  413. __attribute__((section("__trace_printk_fmt"))) = \
  414. __builtin_constant_p(fmt) ? fmt : NULL; \
  415. \
  416. __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \
  417. } else \
  418. __trace_printk(_THIS_IP_, fmt, ##args); \
  419. } while (0)
  420. extern __printf(2, 3)
  421. int __trace_bprintk(unsigned long ip, const char *fmt, ...);
  422. extern __printf(2, 3)
  423. int __trace_printk(unsigned long ip, const char *fmt, ...);
  424. extern void trace_dump_stack(void);
  425. /*
  426. * The double __builtin_constant_p is because gcc will give us an error
  427. * if we try to allocate the static variable to fmt if it is not a
  428. * constant. Even with the outer if statement.
  429. */
  430. #define ftrace_vprintk(fmt, vargs) \
  431. do { \
  432. if (__builtin_constant_p(fmt)) { \
  433. static const char *trace_printk_fmt \
  434. __attribute__((section("__trace_printk_fmt"))) = \
  435. __builtin_constant_p(fmt) ? fmt : NULL; \
  436. \
  437. __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs); \
  438. } else \
  439. __ftrace_vprintk(_THIS_IP_, fmt, vargs); \
  440. } while (0)
  441. extern int
  442. __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
  443. extern int
  444. __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
  445. extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
  446. #else
  447. static inline __printf(1, 2)
  448. int trace_printk(const char *fmt, ...);
  449. static inline void tracing_start(void) { }
  450. static inline void tracing_stop(void) { }
  451. static inline void ftrace_off_permanent(void) { }
  452. static inline void trace_dump_stack(void) { }
  453. static inline int
  454. trace_printk(const char *fmt, ...)
  455. {
  456. return 0;
  457. }
  458. static inline int
  459. ftrace_vprintk(const char *fmt, va_list ap)
  460. {
  461. return 0;
  462. }
  463. static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
  464. #endif /* CONFIG_TRACING */
  465. /*
  466. * min()/max()/clamp() macros that also do
  467. * strict type-checking.. See the
  468. * "unnecessary" pointer comparison.
  469. */
  470. #define min(x, y) ({ \
  471. typeof(x) _min1 = (x); \
  472. typeof(y) _min2 = (y); \
  473. (void) (&_min1 == &_min2); \
  474. _min1 < _min2 ? _min1 : _min2; })
  475. #define max(x, y) ({ \
  476. typeof(x) _max1 = (x); \
  477. typeof(y) _max2 = (y); \
  478. (void) (&_max1 == &_max2); \
  479. _max1 > _max2 ? _max1 : _max2; })
  480. #define min3(x, y, z) ({ \
  481. typeof(x) _min1 = (x); \
  482. typeof(y) _min2 = (y); \
  483. typeof(z) _min3 = (z); \
  484. (void) (&_min1 == &_min2); \
  485. (void) (&_min1 == &_min3); \
  486. _min1 < _min2 ? (_min1 < _min3 ? _min1 : _min3) : \
  487. (_min2 < _min3 ? _min2 : _min3); })
  488. #define max3(x, y, z) ({ \
  489. typeof(x) _max1 = (x); \
  490. typeof(y) _max2 = (y); \
  491. typeof(z) _max3 = (z); \
  492. (void) (&_max1 == &_max2); \
  493. (void) (&_max1 == &_max3); \
  494. _max1 > _max2 ? (_max1 > _max3 ? _max1 : _max3) : \
  495. (_max2 > _max3 ? _max2 : _max3); })
  496. /**
  497. * min_not_zero - return the minimum that is _not_ zero, unless both are zero
  498. * @x: value1
  499. * @y: value2
  500. */
  501. #define min_not_zero(x, y) ({ \
  502. typeof(x) __x = (x); \
  503. typeof(y) __y = (y); \
  504. __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
  505. /**
  506. * clamp - return a value clamped to a given range with strict typechecking
  507. * @val: current value
  508. * @min: minimum allowable value
  509. * @max: maximum allowable value
  510. *
  511. * This macro does strict typechecking of min/max to make sure they are of the
  512. * same type as val. See the unnecessary pointer comparisons.
  513. */
  514. #define clamp(val, min, max) ({ \
  515. typeof(val) __val = (val); \
  516. typeof(min) __min = (min); \
  517. typeof(max) __max = (max); \
  518. (void) (&__val == &__min); \
  519. (void) (&__val == &__max); \
  520. __val = __val < __min ? __min: __val; \
  521. __val > __max ? __max: __val; })
  522. /*
  523. * ..and if you can't take the strict
  524. * types, you can specify one yourself.
  525. *
  526. * Or not use min/max/clamp at all, of course.
  527. */
  528. #define min_t(type, x, y) ({ \
  529. type __min1 = (x); \
  530. type __min2 = (y); \
  531. __min1 < __min2 ? __min1: __min2; })
  532. #define max_t(type, x, y) ({ \
  533. type __max1 = (x); \
  534. type __max2 = (y); \
  535. __max1 > __max2 ? __max1: __max2; })
  536. /**
  537. * clamp_t - return a value clamped to a given range using a given type
  538. * @type: the type of variable to use
  539. * @val: current value
  540. * @min: minimum allowable value
  541. * @max: maximum allowable value
  542. *
  543. * This macro does no typechecking and uses temporary variables of type
  544. * 'type' to make all the comparisons.
  545. */
  546. #define clamp_t(type, val, min, max) ({ \
  547. type __val = (val); \
  548. type __min = (min); \
  549. type __max = (max); \
  550. __val = __val < __min ? __min: __val; \
  551. __val > __max ? __max: __val; })
  552. /**
  553. * clamp_val - return a value clamped to a given range using val's type
  554. * @val: current value
  555. * @min: minimum allowable value
  556. * @max: maximum allowable value
  557. *
  558. * This macro does no typechecking and uses temporary variables of whatever
  559. * type the input argument 'val' is. This is useful when val is an unsigned
  560. * type and min and max are literals that will otherwise be assigned a signed
  561. * integer type.
  562. */
  563. #define clamp_val(val, min, max) ({ \
  564. typeof(val) __val = (val); \
  565. typeof(val) __min = (min); \
  566. typeof(val) __max = (max); \
  567. __val = __val < __min ? __min: __val; \
  568. __val > __max ? __max: __val; })
  569. /*
  570. * swap - swap value of @a and @b
  571. */
  572. #define swap(a, b) \
  573. do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
  574. /**
  575. * container_of - cast a member of a structure out to the containing structure
  576. * @ptr: the pointer to the member.
  577. * @type: the type of the container struct this is embedded in.
  578. * @member: the name of the member within the struct.
  579. *
  580. */
  581. #define container_of(ptr, type, member) ({ \
  582. const typeof( ((type *)0)->member ) *__mptr = (ptr); \
  583. (type *)( (char *)__mptr - offsetof(type,member) );})
  584. #ifdef __CHECKER__
  585. #define BUILD_BUG_ON_NOT_POWER_OF_2(n)
  586. #define BUILD_BUG_ON_ZERO(e) (0)
  587. #define BUILD_BUG_ON_NULL(e) ((void*)0)
  588. #define BUILD_BUG_ON(condition)
  589. #define BUILD_BUG() (0)
  590. #else /* __CHECKER__ */
  591. /* Force a compilation error if a constant expression is not a power of 2 */
  592. #define BUILD_BUG_ON_NOT_POWER_OF_2(n) \
  593. BUILD_BUG_ON((n) == 0 || (((n) & ((n) - 1)) != 0))
  594. /* Force a compilation error if condition is true, but also produce a
  595. result (of value 0 and type size_t), so the expression can be used
  596. e.g. in a structure initializer (or where-ever else comma expressions
  597. aren't permitted). */
  598. #define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))
  599. #define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))
  600. /**
  601. * BUILD_BUG_ON - break compile if a condition is true.
  602. * @condition: the condition which the compiler should know is false.
  603. *
  604. * If you have some code which relies on certain constants being equal, or
  605. * other compile-time-evaluated condition, you should use BUILD_BUG_ON to
  606. * detect if someone changes it.
  607. *
  608. * The implementation uses gcc's reluctance to create a negative array, but
  609. * gcc (as of 4.4) only emits that error for obvious cases (eg. not arguments
  610. * to inline functions). So as a fallback we use the optimizer; if it can't
  611. * prove the condition is false, it will cause a link error on the undefined
  612. * "__build_bug_on_failed". This error message can be harder to track down
  613. * though, hence the two different methods.
  614. */
  615. #ifndef __OPTIMIZE__
  616. #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
  617. #else
  618. extern int __build_bug_on_failed;
  619. #define BUILD_BUG_ON(condition) \
  620. do { \
  621. ((void)sizeof(char[1 - 2*!!(condition)])); \
  622. if (condition) __build_bug_on_failed = 1; \
  623. } while(0)
  624. #endif
  625. /**
  626. * BUILD_BUG - break compile if used.
  627. *
  628. * If you have some code that you expect the compiler to eliminate at
  629. * build time, you should use BUILD_BUG to detect if it is
  630. * unexpectedly used.
  631. */
  632. #define BUILD_BUG() \
  633. do { \
  634. extern void __build_bug_failed(void) \
  635. __linktime_error("BUILD_BUG failed"); \
  636. __build_bug_failed(); \
  637. } while (0)
  638. #endif /* __CHECKER__ */
  639. /* Trap pasters of __FUNCTION__ at compile-time */
  640. #define __FUNCTION__ (__func__)
  641. /* This helps us to avoid #ifdef CONFIG_NUMA */
  642. #ifdef CONFIG_NUMA
  643. #define NUMA_BUILD 1
  644. #else
  645. #define NUMA_BUILD 0
  646. #endif
  647. /* This helps us avoid #ifdef CONFIG_COMPACTION */
  648. #ifdef CONFIG_COMPACTION
  649. #define COMPACTION_BUILD 1
  650. #else
  651. #define COMPACTION_BUILD 0
  652. #endif
  653. /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
  654. #ifdef CONFIG_FTRACE_MCOUNT_RECORD
  655. # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
  656. #endif
  657. extern int do_sysinfo(struct sysinfo *info);
  658. #endif /* __KERNEL__ */
  659. #endif