~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/include/linux/kernel.h

Version: ~ [ linux-5.5-rc1 ] ~ [ linux-5.4.2 ] ~ [ linux-5.3.15 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.88 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.158 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.206 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.206 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.78 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  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 U8_MAX          ((u8)~0U)
 33 #define S8_MAX          ((s8)(U8_MAX>>1))
 34 #define S8_MIN          ((s8)(-S8_MAX - 1))
 35 #define U16_MAX         ((u16)~0U)
 36 #define S16_MAX         ((s16)(U16_MAX>>1))
 37 #define S16_MIN         ((s16)(-S16_MAX - 1))
 38 #define U32_MAX         ((u32)~0U)
 39 #define S32_MAX         ((s32)(U32_MAX>>1))
 40 #define S32_MIN         ((s32)(-S32_MAX - 1))
 41 #define U64_MAX         ((u64)~0ULL)
 42 #define S64_MAX         ((s64)(U64_MAX>>1))
 43 #define S64_MIN         ((s64)(-S64_MAX - 1))
 44 
 45 #define STACK_MAGIC     0xdeadbeef
 46 
 47 #define REPEAT_BYTE(x)  ((~0ul / 0xff) * (x))
 48 
 49 #define ALIGN(x, a)             __ALIGN_KERNEL((x), (a))
 50 #define __ALIGN_MASK(x, mask)   __ALIGN_KERNEL_MASK((x), (mask))
 51 #define PTR_ALIGN(p, a)         ((typeof(p))ALIGN((unsigned long)(p), (a)))
 52 #define IS_ALIGNED(x, a)                (((x) & ((typeof(x))(a) - 1)) == 0)
 53 
 54 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
 55 
 56 /*
 57  * This looks more complex than it should be. But we need to
 58  * get the type for the ~ right in round_down (it needs to be
 59  * as wide as the result!), and we want to evaluate the macro
 60  * arguments just once each.
 61  */
 62 #define __round_mask(x, y) ((__typeof__(x))((y)-1))
 63 #define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
 64 #define round_down(x, y) ((x) & ~__round_mask(x, y))
 65 
 66 #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
 67 #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
 68 #define DIV_ROUND_UP_ULL(ll,d) \
 69         ({ unsigned long long _tmp = (ll)+(d)-1; do_div(_tmp, d); _tmp; })
 70 
 71 #if BITS_PER_LONG == 32
 72 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d)
 73 #else
 74 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d)
 75 #endif
 76 
 77 /* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */
 78 #define roundup(x, y) (                                 \
 79 {                                                       \
 80         const typeof(y) __y = y;                        \
 81         (((x) + (__y - 1)) / __y) * __y;                \
 82 }                                                       \
 83 )
 84 #define rounddown(x, y) (                               \
 85 {                                                       \
 86         typeof(x) __x = (x);                            \
 87         __x - (__x % (y));                              \
 88 }                                                       \
 89 )
 90 
 91 /*
 92  * Divide positive or negative dividend by positive divisor and round
 93  * to closest integer. Result is undefined for negative divisors and
 94  * for negative dividends if the divisor variable type is unsigned.
 95  */
 96 #define DIV_ROUND_CLOSEST(x, divisor)(                  \
 97 {                                                       \
 98         typeof(x) __x = x;                              \
 99         typeof(divisor) __d = divisor;                  \
100         (((typeof(x))-1) > 0 ||                         \
101          ((typeof(divisor))-1) > 0 || (__x) > 0) ?      \
102                 (((__x) + ((__d) / 2)) / (__d)) :       \
103                 (((__x) - ((__d) / 2)) / (__d));        \
104 }                                                       \
105 )
106 
107 /*
108  * Multiplies an integer by a fraction, while avoiding unnecessary
109  * overflow or loss of precision.
110  */
111 #define mult_frac(x, numer, denom)(                     \
112 {                                                       \
113         typeof(x) quot = (x) / (denom);                 \
114         typeof(x) rem  = (x) % (denom);                 \
115         (quot * (numer)) + ((rem * (numer)) / (denom)); \
116 }                                                       \
117 )
118 
119 
120 #define _RET_IP_                (unsigned long)__builtin_return_address(0)
121 #define _THIS_IP_  ({ __label__ __here; __here: (unsigned long)&&__here; })
122 
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 /**
138  * upper_32_bits - return bits 32-63 of a number
139  * @n: the number we're accessing
140  *
141  * A basic shift-right of a 64- or 32-bit quantity.  Use this to suppress
142  * the "right shift count >= width of type" warning when that quantity is
143  * 32-bits.
144  */
145 #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
146 
147 /**
148  * lower_32_bits - return bits 0-31 of a number
149  * @n: the number we're accessing
150  */
151 #define lower_32_bits(n) ((u32)(n))
152 
153 struct completion;
154 struct pt_regs;
155 struct user;
156 
157 #ifdef CONFIG_PREEMPT_VOLUNTARY
158 extern int _cond_resched(void);
159 # define might_resched() _cond_resched()
160 #else
161 # define might_resched() do { } while (0)
162 #endif
163 
164 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
165   void __might_sleep(const char *file, int line, int preempt_offset);
166 /**
167  * might_sleep - annotation for functions that can sleep
168  *
169  * this macro will print a stack trace if it is executed in an atomic
170  * context (spinlock, irq-handler, ...).
171  *
172  * This is a useful debugging help to be able to catch problems early and not
173  * be bitten later when the calling function happens to sleep when it is not
174  * supposed to.
175  */
176 # define might_sleep() \
177         do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
178 #else
179   static inline void __might_sleep(const char *file, int line,
180                                    int preempt_offset) { }
181 # define might_sleep() do { might_resched(); } while (0)
182 #endif
183 
184 #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
185 
186 /*
187  * abs() handles unsigned and signed longs, ints, shorts and chars.  For all
188  * input types abs() returns a signed long.
189  * abs() should not be used for 64-bit types (s64, u64, long long) - use abs64()
190  * for those.
191  */
192 #define abs(x) ({                                               \
193                 long ret;                                       \
194                 if (sizeof(x) == sizeof(long)) {                \
195                         long __x = (x);                         \
196                         ret = (__x < 0) ? -__x : __x;           \
197                 } else {                                        \
198                         int __x = (x);                          \
199                         ret = (__x < 0) ? -__x : __x;           \
200                 }                                               \
201                 ret;                                            \
202         })
203 
204 #define abs64(x) ({                             \
205                 s64 __x = (x);                  \
206                 (__x < 0) ? -__x : __x;         \
207         })
208 
209 #ifdef CONFIG_PROVE_LOCKING
210 void might_fault(void);
211 #else
212 static inline void might_fault(void)
213 {
214         might_sleep();
215 }
216 #endif
217 
218 extern struct atomic_notifier_head panic_notifier_list;
219 extern long (*panic_blink)(int state);
220 __printf(1, 2)
221 void panic(const char *fmt, ...)
222         __noreturn __cold;
223 extern void oops_enter(void);
224 extern void oops_exit(void);
225 void print_oops_end_marker(void);
226 extern int oops_may_print(void);
227 void do_exit(long error_code)
228         __noreturn;
229 void complete_and_exit(struct completion *, long)
230         __noreturn;
231 
232 /* Internal, do not use. */
233 int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
234 int __must_check _kstrtol(const char *s, unsigned int base, long *res);
235 
236 int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
237 int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
238 
239 /**
240  * kstrtoul - convert a string to an unsigned long
241  * @s: The start of the string. The string must be null-terminated, and may also
242  *  include a single newline before its terminating null. The first character
243  *  may also be a plus sign, but not a minus sign.
244  * @base: The number base to use. The maximum supported base is 16. If base is
245  *  given as 0, then the base of the string is automatically detected with the
246  *  conventional semantics - If it begins with 0x the number will be parsed as a
247  *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
248  *  parsed as an octal number. Otherwise it will be parsed as a decimal.
249  * @res: Where to write the result of the conversion on success.
250  *
251  * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
252  * Used as a replacement for the obsolete simple_strtoull. Return code must
253  * be checked.
254 */
255 static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
256 {
257         /*
258          * We want to shortcut function call, but
259          * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
260          */
261         if (sizeof(unsigned long) == sizeof(unsigned long long) &&
262             __alignof__(unsigned long) == __alignof__(unsigned long long))
263                 return kstrtoull(s, base, (unsigned long long *)res);
264         else
265                 return _kstrtoul(s, base, res);
266 }
267 
268 /**
269  * kstrtol - convert a string to a long
270  * @s: The start of the string. The string must be null-terminated, and may also
271  *  include a single newline before its terminating null. The first character
272  *  may also be a plus sign or a minus sign.
273  * @base: The number base to use. The maximum supported base is 16. If base is
274  *  given as 0, then the base of the string is automatically detected with the
275  *  conventional semantics - If it begins with 0x the number will be parsed as a
276  *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
277  *  parsed as an octal number. Otherwise it will be parsed as a decimal.
278  * @res: Where to write the result of the conversion on success.
279  *
280  * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
281  * Used as a replacement for the obsolete simple_strtoull. Return code must
282  * be checked.
283  */
284 static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
285 {
286         /*
287          * We want to shortcut function call, but
288          * __builtin_types_compatible_p(long, long long) = 0.
289          */
290         if (sizeof(long) == sizeof(long long) &&
291             __alignof__(long) == __alignof__(long long))
292                 return kstrtoll(s, base, (long long *)res);
293         else
294                 return _kstrtol(s, base, res);
295 }
296 
297 int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
298 int __must_check kstrtoint(const char *s, unsigned int base, int *res);
299 
300 static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
301 {
302         return kstrtoull(s, base, res);
303 }
304 
305 static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
306 {
307         return kstrtoll(s, base, res);
308 }
309 
310 static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
311 {
312         return kstrtouint(s, base, res);
313 }
314 
315 static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
316 {
317         return kstrtoint(s, base, res);
318 }
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 
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 
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 
341 static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
342 {
343         return kstrtoll_from_user(s, count, base, res);
344 }
345 
346 static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
347 {
348         return kstrtouint_from_user(s, count, base, res);
349 }
350 
351 static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
352 {
353         return kstrtoint_from_user(s, count, base, res);
354 }
355 
356 /* Obsolete, do not use.  Use kstrto<foo> instead */
357 
358 extern unsigned long simple_strtoul(const char *,char **,unsigned int);
359 extern long simple_strtol(const char *,char **,unsigned int);
360 extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
361 extern long long simple_strtoll(const char *,char **,unsigned int);
362 #define strict_strtoul  kstrtoul
363 #define strict_strtol   kstrtol
364 #define strict_strtoull kstrtoull
365 #define strict_strtoll  kstrtoll
366 
367 extern int num_to_str(char *buf, int size, unsigned long long num);
368 
369 /* lib/printf utilities */
370 
371 extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
372 extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
373 extern __printf(3, 4)
374 int snprintf(char *buf, size_t size, const char *fmt, ...);
375 extern __printf(3, 0)
376 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
377 extern __printf(3, 4)
378 int scnprintf(char *buf, size_t size, const char *fmt, ...);
379 extern __printf(3, 0)
380 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
381 extern __printf(2, 3)
382 char *kasprintf(gfp_t gfp, const char *fmt, ...);
383 extern char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
384 
385 extern __scanf(2, 3)
386 int sscanf(const char *, const char *, ...);
387 extern __scanf(2, 0)
388 int vsscanf(const char *, const char *, va_list);
389 
390 extern int get_option(char **str, int *pint);
391 extern char *get_options(const char *str, int nints, int *ints);
392 extern unsigned long long memparse(const char *ptr, char **retptr);
393 
394 extern int core_kernel_text(unsigned long addr);
395 extern int core_kernel_data(unsigned long addr);
396 extern int __kernel_text_address(unsigned long addr);
397 extern int kernel_text_address(unsigned long addr);
398 extern int func_ptr_is_kernel_text(void *ptr);
399 
400 struct pid;
401 extern struct pid *session_of_pgrp(struct pid *pgrp);
402 
403 unsigned long int_sqrt(unsigned long);
404 
405 extern void bust_spinlocks(int yes);
406 extern int oops_in_progress;            /* If set, an oops, panic(), BUG() or die() is in progress */
407 extern int panic_timeout;
408 extern int panic_on_oops;
409 extern int panic_on_unrecovered_nmi;
410 extern int panic_on_io_nmi;
411 extern int sysctl_panic_on_stackoverflow;
412 extern const char *print_tainted(void);
413 enum lockdep_ok {
414         LOCKDEP_STILL_OK,
415         LOCKDEP_NOW_UNRELIABLE
416 };
417 extern void add_taint(unsigned flag, enum lockdep_ok);
418 extern int test_taint(unsigned flag);
419 extern unsigned long get_taint(void);
420 extern int root_mountflags;
421 
422 extern bool early_boot_irqs_disabled;
423 
424 /* Values used for system_state */
425 extern enum system_states {
426         SYSTEM_BOOTING,
427         SYSTEM_RUNNING,
428         SYSTEM_HALT,
429         SYSTEM_POWER_OFF,
430         SYSTEM_RESTART,
431 } system_state;
432 
433 #define TAINT_PROPRIETARY_MODULE        0
434 #define TAINT_FORCED_MODULE             1
435 #define TAINT_UNSAFE_SMP                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 
447 extern const char hex_asc[];
448 #define hex_asc_lo(x)   hex_asc[((x) & 0x0f)]
449 #define hex_asc_hi(x)   hex_asc[((x) & 0xf0) >> 4]
450 
451 static inline char *hex_byte_pack(char *buf, u8 byte)
452 {
453         *buf++ = hex_asc_hi(byte);
454         *buf++ = hex_asc_lo(byte);
455         return buf;
456 }
457 
458 static inline char * __deprecated pack_hex_byte(char *buf, u8 byte)
459 {
460         return hex_byte_pack(buf, byte);
461 }
462 
463 extern int hex_to_bin(char ch);
464 extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
465 
466 /*
467  * General tracing related utility functions - trace_printk(),
468  * tracing_on/tracing_off and tracing_start()/tracing_stop
469  *
470  * Use tracing_on/tracing_off when you want to quickly turn on or off
471  * tracing. It simply enables or disables the recording of the trace events.
472  * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
473  * file, which gives a means for the kernel and userspace to interact.
474  * Place a tracing_off() in the kernel where you want tracing to end.
475  * From user space, examine the trace, and then echo 1 > tracing_on
476  * to continue tracing.
477  *
478  * tracing_stop/tracing_start has slightly more overhead. It is used
479  * by things like suspend to ram where disabling the recording of the
480  * trace is not enough, but tracing must actually stop because things
481  * like calling smp_processor_id() may crash the system.
482  *
483  * Most likely, you want to use tracing_on/tracing_off.
484  */
485 #ifdef CONFIG_RING_BUFFER
486 /* trace_off_permanent stops recording with no way to bring it back */
487 void tracing_off_permanent(void);
488 #else
489 static inline void tracing_off_permanent(void) { }
490 #endif
491 
492 enum ftrace_dump_mode {
493         DUMP_NONE,
494         DUMP_ALL,
495         DUMP_ORIG,
496 };
497 
498 #ifdef CONFIG_TRACING
499 void tracing_on(void);
500 void tracing_off(void);
501 int tracing_is_on(void);
502 void tracing_snapshot(void);
503 void tracing_snapshot_alloc(void);
504 
505 extern void tracing_start(void);
506 extern void tracing_stop(void);
507 extern void ftrace_off_permanent(void);
508 
509 static inline __printf(1, 2)
510 void ____trace_printk_check_format(const char *fmt, ...)
511 {
512 }
513 #define __trace_printk_check_format(fmt, args...)                       \
514 do {                                                                    \
515         if (0)                                                          \
516                 ____trace_printk_check_format(fmt, ##args);             \
517 } while (0)
518 
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 
549 #define trace_printk(fmt, ...)                          \
550 do {                                                    \
551         char _______STR[] = __stringify((__VA_ARGS__)); \
552         if (sizeof(_______STR) > 3)                     \
553                 do_trace_printk(fmt, ##__VA_ARGS__);    \
554         else                                            \
555                 trace_puts(fmt);                        \
556 } while (0)
557 
558 #define do_trace_printk(fmt, args...)                                   \
559 do {                                                                    \
560         static const char *trace_printk_fmt __used                      \
561                 __attribute__((section("__trace_printk_fmt"))) =        \
562                 __builtin_constant_p(fmt) ? fmt : NULL;                 \
563                                                                         \
564         __trace_printk_check_format(fmt, ##args);                       \
565                                                                         \
566         if (__builtin_constant_p(fmt))                                  \
567                 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args);   \
568         else                                                            \
569                 __trace_printk(_THIS_IP_, fmt, ##args);                 \
570 } while (0)
571 
572 extern __printf(2, 3)
573 int __trace_bprintk(unsigned long ip, const char *fmt, ...);
574 
575 extern __printf(2, 3)
576 int __trace_printk(unsigned long ip, const char *fmt, ...);
577 
578 extern int __trace_bputs(unsigned long ip, const char *str);
579 extern int __trace_puts(unsigned long ip, const char *str, int size);
580 
581 /**
582  * trace_puts - write a string into the ftrace buffer
583  * @str: the string to record
584  *
585  * Note: __trace_bputs is an internal function for trace_puts and
586  *       the @ip is passed in via the trace_puts macro.
587  *
588  * This is similar to trace_printk() but is made for those really fast
589  * paths that a developer wants the least amount of "Heisenbug" affects,
590  * where the processing of the print format is still too much.
591  *
592  * This function allows a kernel developer to debug fast path sections
593  * that printk is not appropriate for. By scattering in various
594  * printk like tracing in the code, a developer can quickly see
595  * where problems are occurring.
596  *
597  * This is intended as a debugging tool for the developer only.
598  * Please refrain from leaving trace_puts scattered around in
599  * your code. (Extra memory is used for special buffers that are
600  * allocated when trace_puts() is used)
601  *
602  * Returns: 0 if nothing was written, positive # if string was.
603  *  (1 when __trace_bputs is used, strlen(str) when __trace_puts is used)
604  */
605 
606 #define trace_puts(str) ({                                              \
607         static const char *trace_printk_fmt __used                      \
608                 __attribute__((section("__trace_printk_fmt"))) =        \
609                 __builtin_constant_p(str) ? str : NULL;                 \
610                                                                         \
611         if (__builtin_constant_p(str))                                  \
612                 __trace_bputs(_THIS_IP_, trace_printk_fmt);             \
613         else                                                            \
614                 __trace_puts(_THIS_IP_, str, strlen(str));              \
615 })
616 
617 extern void trace_dump_stack(int skip);
618 
619 /*
620  * The double __builtin_constant_p is because gcc will give us an error
621  * if we try to allocate the static variable to fmt if it is not a
622  * constant. Even with the outer if statement.
623  */
624 #define ftrace_vprintk(fmt, vargs)                                      \
625 do {                                                                    \
626         if (__builtin_constant_p(fmt)) {                                \
627                 static const char *trace_printk_fmt __used              \
628                   __attribute__((section("__trace_printk_fmt"))) =      \
629                         __builtin_constant_p(fmt) ? fmt : NULL;         \
630                                                                         \
631                 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs);  \
632         } else                                                          \
633                 __ftrace_vprintk(_THIS_IP_, fmt, vargs);                \
634 } while (0)
635 
636 extern int
637 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
638 
639 extern int
640 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
641 
642 extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
643 #else
644 static inline void tracing_start(void) { }
645 static inline void tracing_stop(void) { }
646 static inline void ftrace_off_permanent(void) { }
647 static inline void trace_dump_stack(void) { }
648 
649 static inline void tracing_on(void) { }
650 static inline void tracing_off(void) { }
651 static inline int tracing_is_on(void) { return 0; }
652 static inline void tracing_snapshot(void) { }
653 static inline void tracing_snapshot_alloc(void) { }
654 
655 static inline __printf(1, 2)
656 int trace_printk(const char *fmt, ...)
657 {
658         return 0;
659 }
660 static inline int
661 ftrace_vprintk(const char *fmt, va_list ap)
662 {
663         return 0;
664 }
665 static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
666 #endif /* CONFIG_TRACING */
667 
668 /*
669  * min()/max()/clamp() macros that also do
670  * strict type-checking.. See the
671  * "unnecessary" pointer comparison.
672  */
673 #define min(x, y) ({                            \
674         typeof(x) _min1 = (x);                  \
675         typeof(y) _min2 = (y);                  \
676         (void) (&_min1 == &_min2);              \
677         _min1 < _min2 ? _min1 : _min2; })
678 
679 #define max(x, y) ({                            \
680         typeof(x) _max1 = (x);                  \
681         typeof(y) _max2 = (y);                  \
682         (void) (&_max1 == &_max2);              \
683         _max1 > _max2 ? _max1 : _max2; })
684 
685 #define min3(x, y, z) ({                        \
686         typeof(x) _min1 = (x);                  \
687         typeof(y) _min2 = (y);                  \
688         typeof(z) _min3 = (z);                  \
689         (void) (&_min1 == &_min2);              \
690         (void) (&_min1 == &_min3);              \
691         _min1 < _min2 ? (_min1 < _min3 ? _min1 : _min3) : \
692                 (_min2 < _min3 ? _min2 : _min3); })
693 
694 #define max3(x, y, z) ({                        \
695         typeof(x) _max1 = (x);                  \
696         typeof(y) _max2 = (y);                  \
697         typeof(z) _max3 = (z);                  \
698         (void) (&_max1 == &_max2);              \
699         (void) (&_max1 == &_max3);              \
700         _max1 > _max2 ? (_max1 > _max3 ? _max1 : _max3) : \
701                 (_max2 > _max3 ? _max2 : _max3); })
702 
703 /**
704  * min_not_zero - return the minimum that is _not_ zero, unless both are zero
705  * @x: value1
706  * @y: value2
707  */
708 #define min_not_zero(x, y) ({                   \
709         typeof(x) __x = (x);                    \
710         typeof(y) __y = (y);                    \
711         __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
712 
713 /**
714  * clamp - return a value clamped to a given range with strict typechecking
715  * @val: current value
716  * @min: minimum allowable value
717  * @max: maximum allowable value
718  *
719  * This macro does strict typechecking of min/max to make sure they are of the
720  * same type as val.  See the unnecessary pointer comparisons.
721  */
722 #define clamp(val, min, max) ({                 \
723         typeof(val) __val = (val);              \
724         typeof(min) __min = (min);              \
725         typeof(max) __max = (max);              \
726         (void) (&__val == &__min);              \
727         (void) (&__val == &__max);              \
728         __val = __val < __min ? __min: __val;   \
729         __val > __max ? __max: __val; })
730 
731 /*
732  * ..and if you can't take the strict
733  * types, you can specify one yourself.
734  *
735  * Or not use min/max/clamp at all, of course.
736  */
737 #define min_t(type, x, y) ({                    \
738         type __min1 = (x);                      \
739         type __min2 = (y);                      \
740         __min1 < __min2 ? __min1: __min2; })
741 
742 #define max_t(type, x, y) ({                    \
743         type __max1 = (x);                      \
744         type __max2 = (y);                      \
745         __max1 > __max2 ? __max1: __max2; })
746 
747 /**
748  * clamp_t - return a value clamped to a given range using a given type
749  * @type: the type of variable to use
750  * @val: current value
751  * @min: minimum allowable value
752  * @max: maximum allowable value
753  *
754  * This macro does no typechecking and uses temporary variables of type
755  * 'type' to make all the comparisons.
756  */
757 #define clamp_t(type, val, min, max) ({         \
758         type __val = (val);                     \
759         type __min = (min);                     \
760         type __max = (max);                     \
761         __val = __val < __min ? __min: __val;   \
762         __val > __max ? __max: __val; })
763 
764 /**
765  * clamp_val - return a value clamped to a given range using val's type
766  * @val: current value
767  * @min: minimum allowable value
768  * @max: maximum allowable value
769  *
770  * This macro does no typechecking and uses temporary variables of whatever
771  * type the input argument 'val' is.  This is useful when val is an unsigned
772  * type and min and max are literals that will otherwise be assigned a signed
773  * integer type.
774  */
775 #define clamp_val(val, min, max) ({             \
776         typeof(val) __val = (val);              \
777         typeof(val) __min = (min);              \
778         typeof(val) __max = (max);              \
779         __val = __val < __min ? __min: __val;   \
780         __val > __max ? __max: __val; })
781 
782 
783 /*
784  * swap - swap value of @a and @b
785  */
786 #define swap(a, b) \
787         do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
788 
789 /**
790  * container_of - cast a member of a structure out to the containing structure
791  * @ptr:        the pointer to the member.
792  * @type:       the type of the container struct this is embedded in.
793  * @member:     the name of the member within the struct.
794  *
795  */
796 #define container_of(ptr, type, member) ({                      \
797         const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
798         (type *)( (char *)__mptr - offsetof(type,member) );})
799 
800 /* Trap pasters of __FUNCTION__ at compile-time */
801 #define __FUNCTION__ (__func__)
802 
803 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
804 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
805 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
806 #endif
807 
808 #endif
809 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp