Version:  2.0.40 2.2.26 2.4.37 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10

Linux/include/linux/kernel.h

  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/dynamic_debug.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 STACK_MAGIC     0xdeadbeef
 33 
 34 #define REPEAT_BYTE(x)  ((~0ul / 0xff) * (x))
 35 
 36 #define ALIGN(x, a)             __ALIGN_KERNEL((x), (a))
 37 #define __ALIGN_MASK(x, mask)   __ALIGN_KERNEL_MASK((x), (mask))
 38 #define PTR_ALIGN(p, a)         ((typeof(p))ALIGN((unsigned long)(p), (a)))
 39 #define IS_ALIGNED(x, a)                (((x) & ((typeof(x))(a) - 1)) == 0)
 40 
 41 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
 42 
 43 /*
 44  * This looks more complex than it should be. But we need to
 45  * get the type for the ~ right in round_down (it needs to be
 46  * as wide as the result!), and we want to evaluate the macro
 47  * arguments just once each.
 48  */
 49 #define __round_mask(x, y) ((__typeof__(x))((y)-1))
 50 #define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
 51 #define round_down(x, y) ((x) & ~__round_mask(x, y))
 52 
 53 #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
 54 #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
 55 #define DIV_ROUND_UP_ULL(ll,d) \
 56         ({ unsigned long long _tmp = (ll)+(d)-1; do_div(_tmp, d); _tmp; })
 57 
 58 #if BITS_PER_LONG == 32
 59 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d)
 60 #else
 61 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d)
 62 #endif
 63 
 64 /* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */
 65 #define roundup(x, y) (                                 \
 66 {                                                       \
 67         const typeof(y) __y = y;                        \
 68         (((x) + (__y - 1)) / __y) * __y;                \
 69 }                                                       \
 70 )
 71 #define rounddown(x, y) (                               \
 72 {                                                       \
 73         typeof(x) __x = (x);                            \
 74         __x - (__x % (y));                              \
 75 }                                                       \
 76 )
 77 
 78 /*
 79  * Divide positive or negative dividend by positive divisor and round
 80  * to closest integer. Result is undefined for negative divisors and
 81  * for negative dividends if the divisor variable type is unsigned.
 82  */
 83 #define DIV_ROUND_CLOSEST(x, divisor)(                  \
 84 {                                                       \
 85         typeof(x) __x = x;                              \
 86         typeof(divisor) __d = divisor;                  \
 87         (((typeof(x))-1) > 0 ||                         \
 88          ((typeof(divisor))-1) > 0 || (__x) > 0) ?      \
 89                 (((__x) + ((__d) / 2)) / (__d)) :       \
 90                 (((__x) - ((__d) / 2)) / (__d));        \
 91 }                                                       \
 92 )
 93 
 94 /*
 95  * Multiplies an integer by a fraction, while avoiding unnecessary
 96  * overflow or loss of precision.
 97  */
 98 #define mult_frac(x, numer, denom)(                     \
 99 {                                                       \
100         typeof(x) quot = (x) / (denom);                 \
101         typeof(x) rem  = (x) % (denom);                 \
102         (quot * (numer)) + ((rem * (numer)) / (denom)); \
103 }                                                       \
104 )
105 
106 
107 #define _RET_IP_                (unsigned long)__builtin_return_address(0)
108 #define _THIS_IP_  ({ __label__ __here; __here: (unsigned long)&&__here; })
109 
110 #ifdef CONFIG_LBDAF
111 # include <asm/div64.h>
112 # define sector_div(a, b) do_div(a, b)
113 #else
114 # define sector_div(n, b)( \
115 { \
116         int _res; \
117         _res = (n) % (b); \
118         (n) /= (b); \
119         _res; \
120 } \
121 )
122 #endif
123 
124 /**
125  * upper_32_bits - return bits 32-63 of a number
126  * @n: the number we're accessing
127  *
128  * A basic shift-right of a 64- or 32-bit quantity.  Use this to suppress
129  * the "right shift count >= width of type" warning when that quantity is
130  * 32-bits.
131  */
132 #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
133 
134 /**
135  * lower_32_bits - return bits 0-31 of a number
136  * @n: the number we're accessing
137  */
138 #define lower_32_bits(n) ((u32)(n))
139 
140 struct completion;
141 struct pt_regs;
142 struct user;
143 
144 #ifdef CONFIG_PREEMPT_VOLUNTARY
145 extern int _cond_resched(void);
146 # define might_resched() _cond_resched()
147 #else
148 # define might_resched() do { } while (0)
149 #endif
150 
151 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
152   void __might_sleep(const char *file, int line, int preempt_offset);
153 /**
154  * might_sleep - annotation for functions that can sleep
155  *
156  * this macro will print a stack trace if it is executed in an atomic
157  * context (spinlock, irq-handler, ...).
158  *
159  * This is a useful debugging help to be able to catch problems early and not
160  * be bitten later when the calling function happens to sleep when it is not
161  * supposed to.
162  */
163 # define might_sleep() \
164         do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
165 #else
166   static inline void __might_sleep(const char *file, int line,
167                                    int preempt_offset) { }
168 # define might_sleep() do { might_resched(); } while (0)
169 #endif
170 
171 #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
172 
173 /*
174  * abs() handles unsigned and signed longs, ints, shorts and chars.  For all
175  * input types abs() returns a signed long.
176  * abs() should not be used for 64-bit types (s64, u64, long long) - use abs64()
177  * for those.
178  */
179 #define abs(x) ({                                               \
180                 long ret;                                       \
181                 if (sizeof(x) == sizeof(long)) {                \
182                         long __x = (x);                         \
183                         ret = (__x < 0) ? -__x : __x;           \
184                 } else {                                        \
185                         int __x = (x);                          \
186                         ret = (__x < 0) ? -__x : __x;           \
187                 }                                               \
188                 ret;                                            \
189         })
190 
191 #define abs64(x) ({                             \
192                 s64 __x = (x);                  \
193                 (__x < 0) ? -__x : __x;         \
194         })
195 
196 #if defined(CONFIG_MMU) && \
197         (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP))
198 void might_fault(void);
199 #else
200 static inline void might_fault(void) { }
201 #endif
202 
203 extern struct atomic_notifier_head panic_notifier_list;
204 extern long (*panic_blink)(int state);
205 __printf(1, 2)
206 void panic(const char *fmt, ...)
207         __noreturn __cold;
208 extern void oops_enter(void);
209 extern void oops_exit(void);
210 void print_oops_end_marker(void);
211 extern int oops_may_print(void);
212 void do_exit(long error_code)
213         __noreturn;
214 void complete_and_exit(struct completion *, long)
215         __noreturn;
216 
217 /* Internal, do not use. */
218 int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
219 int __must_check _kstrtol(const char *s, unsigned int base, long *res);
220 
221 int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
222 int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
223 
224 /**
225  * kstrtoul - convert a string to an unsigned long
226  * @s: The start of the string. The string must be null-terminated, and may also
227  *  include a single newline before its terminating null. The first character
228  *  may also be a plus sign, but not a minus sign.
229  * @base: The number base to use. The maximum supported base is 16. If base is
230  *  given as 0, then the base of the string is automatically detected with the
231  *  conventional semantics - If it begins with 0x the number will be parsed as a
232  *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
233  *  parsed as an octal number. Otherwise it will be parsed as a decimal.
234  * @res: Where to write the result of the conversion on success.
235  *
236  * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
237  * Used as a replacement for the obsolete simple_strtoull. Return code must
238  * be checked.
239 */
240 static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
241 {
242         /*
243          * We want to shortcut function call, but
244          * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
245          */
246         if (sizeof(unsigned long) == sizeof(unsigned long long) &&
247             __alignof__(unsigned long) == __alignof__(unsigned long long))
248                 return kstrtoull(s, base, (unsigned long long *)res);
249         else
250                 return _kstrtoul(s, base, res);
251 }
252 
253 /**
254  * kstrtol - convert a string to a long
255  * @s: The start of the string. The string must be null-terminated, and may also
256  *  include a single newline before its terminating null. The first character
257  *  may also be a plus sign or a minus sign.
258  * @base: The number base to use. The maximum supported base is 16. If base is
259  *  given as 0, then the base of the string is automatically detected with the
260  *  conventional semantics - If it begins with 0x the number will be parsed as a
261  *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
262  *  parsed as an octal number. Otherwise it will be parsed as a decimal.
263  * @res: Where to write the result of the conversion on success.
264  *
265  * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
266  * Used as a replacement for the obsolete simple_strtoull. Return code must
267  * be checked.
268  */
269 static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
270 {
271         /*
272          * We want to shortcut function call, but
273          * __builtin_types_compatible_p(long, long long) = 0.
274          */
275         if (sizeof(long) == sizeof(long long) &&
276             __alignof__(long) == __alignof__(long long))
277                 return kstrtoll(s, base, (long long *)res);
278         else
279                 return _kstrtol(s, base, res);
280 }
281 
282 int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
283 int __must_check kstrtoint(const char *s, unsigned int base, int *res);
284 
285 static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
286 {
287         return kstrtoull(s, base, res);
288 }
289 
290 static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
291 {
292         return kstrtoll(s, base, res);
293 }
294 
295 static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
296 {
297         return kstrtouint(s, base, res);
298 }
299 
300 static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
301 {
302         return kstrtoint(s, base, res);
303 }
304 
305 int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
306 int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
307 int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
308 int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
309 
310 int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
311 int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
312 int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
313 int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
314 int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
315 int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
316 int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
317 int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
318 int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
319 int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
320 
321 static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
322 {
323         return kstrtoull_from_user(s, count, base, res);
324 }
325 
326 static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
327 {
328         return kstrtoll_from_user(s, count, base, res);
329 }
330 
331 static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
332 {
333         return kstrtouint_from_user(s, count, base, res);
334 }
335 
336 static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
337 {
338         return kstrtoint_from_user(s, count, base, res);
339 }
340 
341 /* Obsolete, do not use.  Use kstrto<foo> instead */
342 
343 extern unsigned long simple_strtoul(const char *,char **,unsigned int);
344 extern long simple_strtol(const char *,char **,unsigned int);
345 extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
346 extern long long simple_strtoll(const char *,char **,unsigned int);
347 #define strict_strtoul  kstrtoul
348 #define strict_strtol   kstrtol
349 #define strict_strtoull kstrtoull
350 #define strict_strtoll  kstrtoll
351 
352 extern int num_to_str(char *buf, int size, unsigned long long num);
353 
354 /* lib/printf utilities */
355 
356 extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
357 extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
358 extern __printf(3, 4)
359 int snprintf(char *buf, size_t size, const char *fmt, ...);
360 extern __printf(3, 0)
361 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
362 extern __printf(3, 4)
363 int scnprintf(char *buf, size_t size, const char *fmt, ...);
364 extern __printf(3, 0)
365 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
366 extern __printf(2, 3)
367 char *kasprintf(gfp_t gfp, const char *fmt, ...);
368 extern char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
369 
370 extern __scanf(2, 3)
371 int sscanf(const char *, const char *, ...);
372 extern __scanf(2, 0)
373 int vsscanf(const char *, const char *, va_list);
374 
375 extern int get_option(char **str, int *pint);
376 extern char *get_options(const char *str, int nints, int *ints);
377 extern unsigned long long memparse(const char *ptr, char **retptr);
378 
379 extern int core_kernel_text(unsigned long addr);
380 extern int core_kernel_data(unsigned long addr);
381 extern int __kernel_text_address(unsigned long addr);
382 extern int kernel_text_address(unsigned long addr);
383 extern int func_ptr_is_kernel_text(void *ptr);
384 
385 struct pid;
386 extern struct pid *session_of_pgrp(struct pid *pgrp);
387 
388 unsigned long int_sqrt(unsigned long);
389 
390 extern void bust_spinlocks(int yes);
391 extern int oops_in_progress;            /* If set, an oops, panic(), BUG() or die() is in progress */
392 extern int panic_timeout;
393 extern int panic_on_oops;
394 extern int panic_on_unrecovered_nmi;
395 extern int panic_on_io_nmi;
396 extern int sysctl_panic_on_stackoverflow;
397 extern const char *print_tainted(void);
398 enum lockdep_ok {
399         LOCKDEP_STILL_OK,
400         LOCKDEP_NOW_UNRELIABLE
401 };
402 extern void add_taint(unsigned flag, enum lockdep_ok);
403 extern int test_taint(unsigned flag);
404 extern unsigned long get_taint(void);
405 extern int root_mountflags;
406 
407 extern bool early_boot_irqs_disabled;
408 
409 /* Values used for system_state */
410 extern enum system_states {
411         SYSTEM_BOOTING,
412         SYSTEM_RUNNING,
413         SYSTEM_HALT,
414         SYSTEM_POWER_OFF,
415         SYSTEM_RESTART,
416 } system_state;
417 
418 #define TAINT_PROPRIETARY_MODULE        0
419 #define TAINT_FORCED_MODULE             1
420 #define TAINT_UNSAFE_SMP                2
421 #define TAINT_FORCED_RMMOD              3
422 #define TAINT_MACHINE_CHECK             4
423 #define TAINT_BAD_PAGE                  5
424 #define TAINT_USER                      6
425 #define TAINT_DIE                       7
426 #define TAINT_OVERRIDDEN_ACPI_TABLE     8
427 #define TAINT_WARN                      9
428 #define TAINT_CRAP                      10
429 #define TAINT_FIRMWARE_WORKAROUND       11
430 #define TAINT_OOT_MODULE                12
431 
432 extern const char hex_asc[];
433 #define hex_asc_lo(x)   hex_asc[((x) & 0x0f)]
434 #define hex_asc_hi(x)   hex_asc[((x) & 0xf0) >> 4]
435 
436 static inline char *hex_byte_pack(char *buf, u8 byte)
437 {
438         *buf++ = hex_asc_hi(byte);
439         *buf++ = hex_asc_lo(byte);
440         return buf;
441 }
442 
443 extern const char hex_asc_upper[];
444 #define hex_asc_upper_lo(x)     hex_asc_upper[((x) & 0x0f)]
445 #define hex_asc_upper_hi(x)     hex_asc_upper[((x) & 0xf0) >> 4]
446 
447 static inline char *hex_byte_pack_upper(char *buf, u8 byte)
448 {
449         *buf++ = hex_asc_upper_hi(byte);
450         *buf++ = hex_asc_upper_lo(byte);
451         return buf;
452 }
453 
454 static inline char * __deprecated pack_hex_byte(char *buf, u8 byte)
455 {
456         return hex_byte_pack(buf, byte);
457 }
458 
459 extern int hex_to_bin(char ch);
460 extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
461 
462 int mac_pton(const char *s, u8 *mac);
463 
464 /*
465  * General tracing related utility functions - trace_printk(),
466  * tracing_on/tracing_off and tracing_start()/tracing_stop
467  *
468  * Use tracing_on/tracing_off when you want to quickly turn on or off
469  * tracing. It simply enables or disables the recording of the trace events.
470  * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
471  * file, which gives a means for the kernel and userspace to interact.
472  * Place a tracing_off() in the kernel where you want tracing to end.
473  * From user space, examine the trace, and then echo 1 > tracing_on
474  * to continue tracing.
475  *
476  * tracing_stop/tracing_start has slightly more overhead. It is used
477  * by things like suspend to ram where disabling the recording of the
478  * trace is not enough, but tracing must actually stop because things
479  * like calling smp_processor_id() may crash the system.
480  *
481  * Most likely, you want to use tracing_on/tracing_off.
482  */
483 #ifdef CONFIG_RING_BUFFER
484 /* trace_off_permanent stops recording with no way to bring it back */
485 void tracing_off_permanent(void);
486 #else
487 static inline void tracing_off_permanent(void) { }
488 #endif
489 
490 enum ftrace_dump_mode {
491         DUMP_NONE,
492         DUMP_ALL,
493         DUMP_ORIG,
494 };
495 
496 #ifdef CONFIG_TRACING
497 void tracing_on(void);
498 void tracing_off(void);
499 int tracing_is_on(void);
500 void tracing_snapshot(void);
501 void tracing_snapshot_alloc(void);
502 
503 extern void tracing_start(void);
504 extern void tracing_stop(void);
505 
506 static inline __printf(1, 2)
507 void ____trace_printk_check_format(const char *fmt, ...)
508 {
509 }
510 #define __trace_printk_check_format(fmt, args...)                       \
511 do {                                                                    \
512         if (0)                                                          \
513                 ____trace_printk_check_format(fmt, ##args);             \
514 } while (0)
515 
516 /**
517  * trace_printk - printf formatting in the ftrace buffer
518  * @fmt: the printf format for printing
519  *
520  * Note: __trace_printk is an internal function for trace_printk and
521  *       the @ip is passed in via the trace_printk macro.
522  *
523  * This function allows a kernel developer to debug fast path sections
524  * that printk is not appropriate for. By scattering in various
525  * printk like tracing in the code, a developer can quickly see
526  * where problems are occurring.
527  *
528  * This is intended as a debugging tool for the developer only.
529  * Please refrain from leaving trace_printks scattered around in
530  * your code. (Extra memory is used for special buffers that are
531  * allocated when trace_printk() is used)
532  *
533  * A little optization trick is done here. If there's only one
534  * argument, there's no need to scan the string for printf formats.
535  * The trace_puts() will suffice. But how can we take advantage of
536  * using trace_puts() when trace_printk() has only one argument?
537  * By stringifying the args and checking the size we can tell
538  * whether or not there are args. __stringify((__VA_ARGS__)) will
539  * turn into "()\0" with a size of 3 when there are no args, anything
540  * else will be bigger. All we need to do is define a string to this,
541  * and then take its size and compare to 3. If it's bigger, use
542  * do_trace_printk() otherwise, optimize it to trace_puts(). Then just
543  * let gcc optimize the rest.
544  */
545 
546 #define trace_printk(fmt, ...)                          \
547 do {                                                    \
548         char _______STR[] = __stringify((__VA_ARGS__)); \
549         if (sizeof(_______STR) > 3)                     \
550                 do_trace_printk(fmt, ##__VA_ARGS__);    \
551         else                                            \
552                 trace_puts(fmt);                        \
553 } while (0)
554 
555 #define do_trace_printk(fmt, args...)                                   \
556 do {                                                                    \
557         static const char *trace_printk_fmt                             \
558                 __attribute__((section("__trace_printk_fmt"))) =        \
559                 __builtin_constant_p(fmt) ? fmt : NULL;                 \
560                                                                         \
561         __trace_printk_check_format(fmt, ##args);                       \
562                                                                         \
563         if (__builtin_constant_p(fmt))                                  \
564                 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args);   \
565         else                                                            \
566                 __trace_printk(_THIS_IP_, fmt, ##args);                 \
567 } while (0)
568 
569 extern __printf(2, 3)
570 int __trace_bprintk(unsigned long ip, const char *fmt, ...);
571 
572 extern __printf(2, 3)
573 int __trace_printk(unsigned long ip, const char *fmt, ...);
574 
575 /**
576  * trace_puts - write a string into the ftrace buffer
577  * @str: the string to record
578  *
579  * Note: __trace_bputs is an internal function for trace_puts and
580  *       the @ip is passed in via the trace_puts macro.
581  *
582  * This is similar to trace_printk() but is made for those really fast
583  * paths that a developer wants the least amount of "Heisenbug" affects,
584  * where the processing of the print format is still too much.
585  *
586  * This function allows a kernel developer to debug fast path sections
587  * that printk is not appropriate for. By scattering in various
588  * printk like tracing in the code, a developer can quickly see
589  * where problems are occurring.
590  *
591  * This is intended as a debugging tool for the developer only.
592  * Please refrain from leaving trace_puts scattered around in
593  * your code. (Extra memory is used for special buffers that are
594  * allocated when trace_puts() is used)
595  *
596  * Returns: 0 if nothing was written, positive # if string was.
597  *  (1 when __trace_bputs is used, strlen(str) when __trace_puts is used)
598  */
599 
600 #define trace_puts(str) ({                                              \
601         static const char *trace_printk_fmt                             \
602                 __attribute__((section("__trace_printk_fmt"))) =        \
603                 __builtin_constant_p(str) ? str : NULL;                 \
604                                                                         \
605         if (__builtin_constant_p(str))                                  \
606                 __trace_bputs(_THIS_IP_, trace_printk_fmt);             \
607         else                                                            \
608                 __trace_puts(_THIS_IP_, str, strlen(str));              \
609 })
610 extern int __trace_bputs(unsigned long ip, const char *str);
611 extern int __trace_puts(unsigned long ip, const char *str, int size);
612 
613 extern void trace_dump_stack(int skip);
614 
615 /*
616  * The double __builtin_constant_p is because gcc will give us an error
617  * if we try to allocate the static variable to fmt if it is not a
618  * constant. Even with the outer if statement.
619  */
620 #define ftrace_vprintk(fmt, vargs)                                      \
621 do {                                                                    \
622         if (__builtin_constant_p(fmt)) {                                \
623                 static const char *trace_printk_fmt                     \
624                   __attribute__((section("__trace_printk_fmt"))) =      \
625                         __builtin_constant_p(fmt) ? fmt : NULL;         \
626                                                                         \
627                 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs);  \
628         } else                                                          \
629                 __ftrace_vprintk(_THIS_IP_, fmt, vargs);                \
630 } while (0)
631 
632 extern int
633 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
634 
635 extern int
636 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
637 
638 extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
639 #else
640 static inline void tracing_start(void) { }
641 static inline void tracing_stop(void) { }
642 static inline void trace_dump_stack(int skip) { }
643 
644 static inline void tracing_on(void) { }
645 static inline void tracing_off(void) { }
646 static inline int tracing_is_on(void) { return 0; }
647 static inline void tracing_snapshot(void) { }
648 static inline void tracing_snapshot_alloc(void) { }
649 
650 static inline __printf(1, 2)
651 int trace_printk(const char *fmt, ...)
652 {
653         return 0;
654 }
655 static inline int
656 ftrace_vprintk(const char *fmt, va_list ap)
657 {
658         return 0;
659 }
660 static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
661 #endif /* CONFIG_TRACING */
662 
663 /*
664  * min()/max()/clamp() macros that also do
665  * strict type-checking.. See the
666  * "unnecessary" pointer comparison.
667  */
668 #define min(x, y) ({                            \
669         typeof(x) _min1 = (x);                  \
670         typeof(y) _min2 = (y);                  \
671         (void) (&_min1 == &_min2);              \
672         _min1 < _min2 ? _min1 : _min2; })
673 
674 #define max(x, y) ({                            \
675         typeof(x) _max1 = (x);                  \
676         typeof(y) _max2 = (y);                  \
677         (void) (&_max1 == &_max2);              \
678         _max1 > _max2 ? _max1 : _max2; })
679 
680 #define min3(x, y, z) ({                        \
681         typeof(x) _min1 = (x);                  \
682         typeof(y) _min2 = (y);                  \
683         typeof(z) _min3 = (z);                  \
684         (void) (&_min1 == &_min2);              \
685         (void) (&_min1 == &_min3);              \
686         _min1 < _min2 ? (_min1 < _min3 ? _min1 : _min3) : \
687                 (_min2 < _min3 ? _min2 : _min3); })
688 
689 #define max3(x, y, z) ({                        \
690         typeof(x) _max1 = (x);                  \
691         typeof(y) _max2 = (y);                  \
692         typeof(z) _max3 = (z);                  \
693         (void) (&_max1 == &_max2);              \
694         (void) (&_max1 == &_max3);              \
695         _max1 > _max2 ? (_max1 > _max3 ? _max1 : _max3) : \
696                 (_max2 > _max3 ? _max2 : _max3); })
697 
698 /**
699  * min_not_zero - return the minimum that is _not_ zero, unless both are zero
700  * @x: value1
701  * @y: value2
702  */
703 #define min_not_zero(x, y) ({                   \
704         typeof(x) __x = (x);                    \
705         typeof(y) __y = (y);                    \
706         __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
707 
708 /**
709  * clamp - return a value clamped to a given range with strict typechecking
710  * @val: current value
711  * @min: minimum allowable value
712  * @max: maximum allowable value
713  *
714  * This macro does strict typechecking of min/max to make sure they are of the
715  * same type as val.  See the unnecessary pointer comparisons.
716  */
717 #define clamp(val, min, max) ({                 \
718         typeof(val) __val = (val);              \
719         typeof(min) __min = (min);              \
720         typeof(max) __max = (max);              \
721         (void) (&__val == &__min);              \
722         (void) (&__val == &__max);              \
723         __val = __val < __min ? __min: __val;   \
724         __val > __max ? __max: __val; })
725 
726 /*
727  * ..and if you can't take the strict
728  * types, you can specify one yourself.
729  *
730  * Or not use min/max/clamp at all, of course.
731  */
732 #define min_t(type, x, y) ({                    \
733         type __min1 = (x);                      \
734         type __min2 = (y);                      \
735         __min1 < __min2 ? __min1: __min2; })
736 
737 #define max_t(type, x, y) ({                    \
738         type __max1 = (x);                      \
739         type __max2 = (y);                      \
740         __max1 > __max2 ? __max1: __max2; })
741 
742 /**
743  * clamp_t - return a value clamped to a given range using a given type
744  * @type: the type of variable to use
745  * @val: current value
746  * @min: minimum allowable value
747  * @max: maximum allowable value
748  *
749  * This macro does no typechecking and uses temporary variables of type
750  * 'type' to make all the comparisons.
751  */
752 #define clamp_t(type, val, min, max) ({         \
753         type __val = (val);                     \
754         type __min = (min);                     \
755         type __max = (max);                     \
756         __val = __val < __min ? __min: __val;   \
757         __val > __max ? __max: __val; })
758 
759 /**
760  * clamp_val - return a value clamped to a given range using val's type
761  * @val: current value
762  * @min: minimum allowable value
763  * @max: maximum allowable value
764  *
765  * This macro does no typechecking and uses temporary variables of whatever
766  * type the input argument 'val' is.  This is useful when val is an unsigned
767  * type and min and max are literals that will otherwise be assigned a signed
768  * integer type.
769  */
770 #define clamp_val(val, min, max) ({             \
771         typeof(val) __val = (val);              \
772         typeof(val) __min = (min);              \
773         typeof(val) __max = (max);              \
774         __val = __val < __min ? __min: __val;   \
775         __val > __max ? __max: __val; })
776 
777 
778 /*
779  * swap - swap value of @a and @b
780  */
781 #define swap(a, b) \
782         do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
783 
784 /**
785  * container_of - cast a member of a structure out to the containing structure
786  * @ptr:        the pointer to the member.
787  * @type:       the type of the container struct this is embedded in.
788  * @member:     the name of the member within the struct.
789  *
790  */
791 #define container_of(ptr, type, member) ({                      \
792         const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
793         (type *)( (char *)__mptr - offsetof(type,member) );})
794 
795 /* Trap pasters of __FUNCTION__ at compile-time */
796 #define __FUNCTION__ (__func__)
797 
798 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
799 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
800 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
801 #endif
802 
803 #endif
804 

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