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

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  1 /* SPDX-License-Identifier: GPL-2.0 */
  2 #ifndef _LINUX_KERNEL_H
  3 #define _LINUX_KERNEL_H
  4 
  5 #include <stdarg.h>
  6 #include <linux/align.h>
  7 #include <linux/limits.h>
  8 #include <linux/linkage.h>
  9 #include <linux/stddef.h>
 10 #include <linux/types.h>
 11 #include <linux/compiler.h>
 12 #include <linux/bitops.h>
 13 #include <linux/log2.h>
 14 #include <linux/math.h>
 15 #include <linux/minmax.h>
 16 #include <linux/typecheck.h>
 17 #include <linux/printk.h>
 18 #include <linux/build_bug.h>
 19 #include <linux/static_call_types.h>
 20 #include <asm/byteorder.h>
 21 
 22 #include <uapi/linux/kernel.h>
 23 
 24 #define STACK_MAGIC     0xdeadbeef
 25 
 26 /**
 27  * REPEAT_BYTE - repeat the value @x multiple times as an unsigned long value
 28  * @x: value to repeat
 29  *
 30  * NOTE: @x is not checked for > 0xff; larger values produce odd results.
 31  */
 32 #define REPEAT_BYTE(x)  ((~0ul / 0xff) * (x))
 33 
 34 /* generic data direction definitions */
 35 #define READ                    0
 36 #define WRITE                   1
 37 
 38 /**
 39  * ARRAY_SIZE - get the number of elements in array @arr
 40  * @arr: array to be sized
 41  */
 42 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
 43 
 44 #define PTR_IF(cond, ptr)       ((cond) ? (ptr) : NULL)
 45 
 46 #define u64_to_user_ptr(x) (            \
 47 {                                       \
 48         typecheck(u64, (x));            \
 49         (void __user *)(uintptr_t)(x);  \
 50 }                                       \
 51 )
 52 
 53 #define typeof_member(T, m)     typeof(((T*)0)->m)
 54 
 55 #define _RET_IP_                (unsigned long)__builtin_return_address(0)
 56 #define _THIS_IP_  ({ __label__ __here; __here: (unsigned long)&&__here; })
 57 
 58 /**
 59  * upper_32_bits - return bits 32-63 of a number
 60  * @n: the number we're accessing
 61  *
 62  * A basic shift-right of a 64- or 32-bit quantity.  Use this to suppress
 63  * the "right shift count >= width of type" warning when that quantity is
 64  * 32-bits.
 65  */
 66 #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
 67 
 68 /**
 69  * lower_32_bits - return bits 0-31 of a number
 70  * @n: the number we're accessing
 71  */
 72 #define lower_32_bits(n) ((u32)((n) & 0xffffffff))
 73 
 74 struct completion;
 75 struct pt_regs;
 76 struct user;
 77 
 78 #ifdef CONFIG_PREEMPT_VOLUNTARY
 79 
 80 extern int __cond_resched(void);
 81 # define might_resched() __cond_resched()
 82 
 83 #elif defined(CONFIG_PREEMPT_DYNAMIC)
 84 
 85 extern int __cond_resched(void);
 86 
 87 DECLARE_STATIC_CALL(might_resched, __cond_resched);
 88 
 89 static __always_inline void might_resched(void)
 90 {
 91         static_call_mod(might_resched)();
 92 }
 93 
 94 #else
 95 
 96 # define might_resched() do { } while (0)
 97 
 98 #endif /* CONFIG_PREEMPT_* */
 99 
100 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
101 extern void ___might_sleep(const char *file, int line, int preempt_offset);
102 extern void __might_sleep(const char *file, int line, int preempt_offset);
103 extern void __cant_sleep(const char *file, int line, int preempt_offset);
104 extern void __cant_migrate(const char *file, int line);
105 
106 /**
107  * might_sleep - annotation for functions that can sleep
108  *
109  * this macro will print a stack trace if it is executed in an atomic
110  * context (spinlock, irq-handler, ...). Additional sections where blocking is
111  * not allowed can be annotated with non_block_start() and non_block_end()
112  * pairs.
113  *
114  * This is a useful debugging help to be able to catch problems early and not
115  * be bitten later when the calling function happens to sleep when it is not
116  * supposed to.
117  */
118 # define might_sleep() \
119         do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
120 /**
121  * cant_sleep - annotation for functions that cannot sleep
122  *
123  * this macro will print a stack trace if it is executed with preemption enabled
124  */
125 # define cant_sleep() \
126         do { __cant_sleep(__FILE__, __LINE__, 0); } while (0)
127 # define sched_annotate_sleep() (current->task_state_change = 0)
128 
129 /**
130  * cant_migrate - annotation for functions that cannot migrate
131  *
132  * Will print a stack trace if executed in code which is migratable
133  */
134 # define cant_migrate()                                                 \
135         do {                                                            \
136                 if (IS_ENABLED(CONFIG_SMP))                             \
137                         __cant_migrate(__FILE__, __LINE__);             \
138         } while (0)
139 
140 /**
141  * non_block_start - annotate the start of section where sleeping is prohibited
142  *
143  * This is on behalf of the oom reaper, specifically when it is calling the mmu
144  * notifiers. The problem is that if the notifier were to block on, for example,
145  * mutex_lock() and if the process which holds that mutex were to perform a
146  * sleeping memory allocation, the oom reaper is now blocked on completion of
147  * that memory allocation. Other blocking calls like wait_event() pose similar
148  * issues.
149  */
150 # define non_block_start() (current->non_block_count++)
151 /**
152  * non_block_end - annotate the end of section where sleeping is prohibited
153  *
154  * Closes a section opened by non_block_start().
155  */
156 # define non_block_end() WARN_ON(current->non_block_count-- == 0)
157 #else
158   static inline void ___might_sleep(const char *file, int line,
159                                    int preempt_offset) { }
160   static inline void __might_sleep(const char *file, int line,
161                                    int preempt_offset) { }
162 # define might_sleep() do { might_resched(); } while (0)
163 # define cant_sleep() do { } while (0)
164 # define cant_migrate()         do { } while (0)
165 # define sched_annotate_sleep() do { } while (0)
166 # define non_block_start() do { } while (0)
167 # define non_block_end() do { } while (0)
168 #endif
169 
170 #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
171 
172 #if defined(CONFIG_MMU) && \
173         (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP))
174 #define might_fault() __might_fault(__FILE__, __LINE__)
175 void __might_fault(const char *file, int line);
176 #else
177 static inline void might_fault(void) { }
178 #endif
179 
180 extern struct atomic_notifier_head panic_notifier_list;
181 extern long (*panic_blink)(int state);
182 __printf(1, 2)
183 void panic(const char *fmt, ...) __noreturn __cold;
184 void nmi_panic(struct pt_regs *regs, const char *msg);
185 extern void oops_enter(void);
186 extern void oops_exit(void);
187 extern bool oops_may_print(void);
188 void do_exit(long error_code) __noreturn;
189 void complete_and_exit(struct completion *, long) __noreturn;
190 
191 /* Internal, do not use. */
192 int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
193 int __must_check _kstrtol(const char *s, unsigned int base, long *res);
194 
195 int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
196 int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
197 
198 /**
199  * kstrtoul - convert a string to an unsigned long
200  * @s: The start of the string. The string must be null-terminated, and may also
201  *  include a single newline before its terminating null. The first character
202  *  may also be a plus sign, but not a minus sign.
203  * @base: The number base to use. The maximum supported base is 16. If base is
204  *  given as 0, then the base of the string is automatically detected with the
205  *  conventional semantics - If it begins with 0x the number will be parsed as a
206  *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
207  *  parsed as an octal number. Otherwise it will be parsed as a decimal.
208  * @res: Where to write the result of the conversion on success.
209  *
210  * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
211  * Preferred over simple_strtoul(). Return code must be checked.
212 */
213 static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
214 {
215         /*
216          * We want to shortcut function call, but
217          * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
218          */
219         if (sizeof(unsigned long) == sizeof(unsigned long long) &&
220             __alignof__(unsigned long) == __alignof__(unsigned long long))
221                 return kstrtoull(s, base, (unsigned long long *)res);
222         else
223                 return _kstrtoul(s, base, res);
224 }
225 
226 /**
227  * kstrtol - convert a string to a long
228  * @s: The start of the string. The string must be null-terminated, and may also
229  *  include a single newline before its terminating null. The first character
230  *  may also be a plus sign or a minus sign.
231  * @base: The number base to use. The maximum supported base is 16. If base is
232  *  given as 0, then the base of the string is automatically detected with the
233  *  conventional semantics - If it begins with 0x the number will be parsed as a
234  *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
235  *  parsed as an octal number. Otherwise it will be parsed as a decimal.
236  * @res: Where to write the result of the conversion on success.
237  *
238  * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
239  * Preferred over simple_strtol(). Return code must be checked.
240  */
241 static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
242 {
243         /*
244          * We want to shortcut function call, but
245          * __builtin_types_compatible_p(long, long long) = 0.
246          */
247         if (sizeof(long) == sizeof(long long) &&
248             __alignof__(long) == __alignof__(long long))
249                 return kstrtoll(s, base, (long long *)res);
250         else
251                 return _kstrtol(s, base, res);
252 }
253 
254 int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
255 int __must_check kstrtoint(const char *s, unsigned int base, int *res);
256 
257 static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
258 {
259         return kstrtoull(s, base, res);
260 }
261 
262 static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
263 {
264         return kstrtoll(s, base, res);
265 }
266 
267 static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
268 {
269         return kstrtouint(s, base, res);
270 }
271 
272 static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
273 {
274         return kstrtoint(s, base, res);
275 }
276 
277 int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
278 int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
279 int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
280 int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
281 int __must_check kstrtobool(const char *s, bool *res);
282 
283 int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
284 int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
285 int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
286 int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
287 int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
288 int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
289 int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
290 int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
291 int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
292 int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
293 int __must_check kstrtobool_from_user(const char __user *s, size_t count, bool *res);
294 
295 static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
296 {
297         return kstrtoull_from_user(s, count, base, res);
298 }
299 
300 static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
301 {
302         return kstrtoll_from_user(s, count, base, res);
303 }
304 
305 static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
306 {
307         return kstrtouint_from_user(s, count, base, res);
308 }
309 
310 static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
311 {
312         return kstrtoint_from_user(s, count, base, res);
313 }
314 
315 /*
316  * Use kstrto<foo> instead.
317  *
318  * NOTE: simple_strto<foo> does not check for the range overflow and,
319  *       depending on the input, may give interesting results.
320  *
321  * Use these functions if and only if you cannot use kstrto<foo>, because
322  * the conversion ends on the first non-digit character, which may be far
323  * beyond the supported range. It might be useful to parse the strings like
324  * 10x50 or 12:21 without altering original string or temporary buffer in use.
325  * Keep in mind above caveat.
326  */
327 
328 extern unsigned long simple_strtoul(const char *,char **,unsigned int);
329 extern long simple_strtol(const char *,char **,unsigned int);
330 extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
331 extern long long simple_strtoll(const char *,char **,unsigned int);
332 
333 extern int num_to_str(char *buf, int size,
334                       unsigned long long num, unsigned int width);
335 
336 /* lib/printf utilities */
337 
338 extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
339 extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
340 extern __printf(3, 4)
341 int snprintf(char *buf, size_t size, const char *fmt, ...);
342 extern __printf(3, 0)
343 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
344 extern __printf(3, 4)
345 int scnprintf(char *buf, size_t size, const char *fmt, ...);
346 extern __printf(3, 0)
347 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
348 extern __printf(2, 3) __malloc
349 char *kasprintf(gfp_t gfp, const char *fmt, ...);
350 extern __printf(2, 0) __malloc
351 char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
352 extern __printf(2, 0)
353 const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list args);
354 
355 extern __scanf(2, 3)
356 int sscanf(const char *, const char *, ...);
357 extern __scanf(2, 0)
358 int vsscanf(const char *, const char *, va_list);
359 
360 extern int get_option(char **str, int *pint);
361 extern char *get_options(const char *str, int nints, int *ints);
362 extern unsigned long long memparse(const char *ptr, char **retptr);
363 extern bool parse_option_str(const char *str, const char *option);
364 extern char *next_arg(char *args, char **param, char **val);
365 
366 extern int core_kernel_text(unsigned long addr);
367 extern int init_kernel_text(unsigned long addr);
368 extern int core_kernel_data(unsigned long addr);
369 extern int __kernel_text_address(unsigned long addr);
370 extern int kernel_text_address(unsigned long addr);
371 extern int func_ptr_is_kernel_text(void *ptr);
372 
373 #ifdef CONFIG_SMP
374 extern unsigned int sysctl_oops_all_cpu_backtrace;
375 #else
376 #define sysctl_oops_all_cpu_backtrace 0
377 #endif /* CONFIG_SMP */
378 
379 extern void bust_spinlocks(int yes);
380 extern int panic_timeout;
381 extern unsigned long panic_print;
382 extern int panic_on_oops;
383 extern int panic_on_unrecovered_nmi;
384 extern int panic_on_io_nmi;
385 extern int panic_on_warn;
386 extern unsigned long panic_on_taint;
387 extern bool panic_on_taint_nousertaint;
388 extern int sysctl_panic_on_rcu_stall;
389 extern int sysctl_max_rcu_stall_to_panic;
390 extern int sysctl_panic_on_stackoverflow;
391 
392 extern bool crash_kexec_post_notifiers;
393 
394 /*
395  * panic_cpu is used for synchronizing panic() and crash_kexec() execution. It
396  * holds a CPU number which is executing panic() currently. A value of
397  * PANIC_CPU_INVALID means no CPU has entered panic() or crash_kexec().
398  */
399 extern atomic_t panic_cpu;
400 #define PANIC_CPU_INVALID       -1
401 
402 /*
403  * Only to be used by arch init code. If the user over-wrote the default
404  * CONFIG_PANIC_TIMEOUT, honor it.
405  */
406 static inline void set_arch_panic_timeout(int timeout, int arch_default_timeout)
407 {
408         if (panic_timeout == arch_default_timeout)
409                 panic_timeout = timeout;
410 }
411 extern const char *print_tainted(void);
412 enum lockdep_ok {
413         LOCKDEP_STILL_OK,
414         LOCKDEP_NOW_UNRELIABLE
415 };
416 extern void add_taint(unsigned flag, enum lockdep_ok);
417 extern int test_taint(unsigned flag);
418 extern unsigned long get_taint(void);
419 extern int root_mountflags;
420 
421 extern bool early_boot_irqs_disabled;
422 
423 /*
424  * Values used for system_state. Ordering of the states must not be changed
425  * as code checks for <, <=, >, >= STATE.
426  */
427 extern enum system_states {
428         SYSTEM_BOOTING,
429         SYSTEM_SCHEDULING,
430         SYSTEM_RUNNING,
431         SYSTEM_HALT,
432         SYSTEM_POWER_OFF,
433         SYSTEM_RESTART,
434         SYSTEM_SUSPEND,
435 } system_state;
436 
437 /* This cannot be an enum because some may be used in assembly source. */
438 #define TAINT_PROPRIETARY_MODULE        0
439 #define TAINT_FORCED_MODULE             1
440 #define TAINT_CPU_OUT_OF_SPEC           2
441 #define TAINT_FORCED_RMMOD              3
442 #define TAINT_MACHINE_CHECK             4
443 #define TAINT_BAD_PAGE                  5
444 #define TAINT_USER                      6
445 #define TAINT_DIE                       7
446 #define TAINT_OVERRIDDEN_ACPI_TABLE     8
447 #define TAINT_WARN                      9
448 #define TAINT_CRAP                      10
449 #define TAINT_FIRMWARE_WORKAROUND       11
450 #define TAINT_OOT_MODULE                12
451 #define TAINT_UNSIGNED_MODULE           13
452 #define TAINT_SOFTLOCKUP                14
453 #define TAINT_LIVEPATCH                 15
454 #define TAINT_AUX                       16
455 #define TAINT_RANDSTRUCT                17
456 #define TAINT_FLAGS_COUNT               18
457 #define TAINT_FLAGS_MAX                 ((1UL << TAINT_FLAGS_COUNT) - 1)
458 
459 struct taint_flag {
460         char c_true;    /* character printed when tainted */
461         char c_false;   /* character printed when not tainted */
462         bool module;    /* also show as a per-module taint flag */
463 };
464 
465 extern const struct taint_flag taint_flags[TAINT_FLAGS_COUNT];
466 
467 extern const char hex_asc[];
468 #define hex_asc_lo(x)   hex_asc[((x) & 0x0f)]
469 #define hex_asc_hi(x)   hex_asc[((x) & 0xf0) >> 4]
470 
471 static inline char *hex_byte_pack(char *buf, u8 byte)
472 {
473         *buf++ = hex_asc_hi(byte);
474         *buf++ = hex_asc_lo(byte);
475         return buf;
476 }
477 
478 extern const char hex_asc_upper[];
479 #define hex_asc_upper_lo(x)     hex_asc_upper[((x) & 0x0f)]
480 #define hex_asc_upper_hi(x)     hex_asc_upper[((x) & 0xf0) >> 4]
481 
482 static inline char *hex_byte_pack_upper(char *buf, u8 byte)
483 {
484         *buf++ = hex_asc_upper_hi(byte);
485         *buf++ = hex_asc_upper_lo(byte);
486         return buf;
487 }
488 
489 extern int hex_to_bin(char ch);
490 extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
491 extern char *bin2hex(char *dst, const void *src, size_t count);
492 
493 bool mac_pton(const char *s, u8 *mac);
494 
495 /*
496  * General tracing related utility functions - trace_printk(),
497  * tracing_on/tracing_off and tracing_start()/tracing_stop
498  *
499  * Use tracing_on/tracing_off when you want to quickly turn on or off
500  * tracing. It simply enables or disables the recording of the trace events.
501  * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
502  * file, which gives a means for the kernel and userspace to interact.
503  * Place a tracing_off() in the kernel where you want tracing to end.
504  * From user space, examine the trace, and then echo 1 > tracing_on
505  * to continue tracing.
506  *
507  * tracing_stop/tracing_start has slightly more overhead. It is used
508  * by things like suspend to ram where disabling the recording of the
509  * trace is not enough, but tracing must actually stop because things
510  * like calling smp_processor_id() may crash the system.
511  *
512  * Most likely, you want to use tracing_on/tracing_off.
513  */
514 
515 enum ftrace_dump_mode {
516         DUMP_NONE,
517         DUMP_ALL,
518         DUMP_ORIG,
519 };
520 
521 #ifdef CONFIG_TRACING
522 void tracing_on(void);
523 void tracing_off(void);
524 int tracing_is_on(void);
525 void tracing_snapshot(void);
526 void tracing_snapshot_alloc(void);
527 
528 extern void tracing_start(void);
529 extern void tracing_stop(void);
530 
531 static inline __printf(1, 2)
532 void ____trace_printk_check_format(const char *fmt, ...)
533 {
534 }
535 #define __trace_printk_check_format(fmt, args...)                       \
536 do {                                                                    \
537         if (0)                                                          \
538                 ____trace_printk_check_format(fmt, ##args);             \
539 } while (0)
540 
541 /**
542  * trace_printk - printf formatting in the ftrace buffer
543  * @fmt: the printf format for printing
544  *
545  * Note: __trace_printk is an internal function for trace_printk() and
546  *       the @ip is passed in via the trace_printk() macro.
547  *
548  * This function allows a kernel developer to debug fast path sections
549  * that printk is not appropriate for. By scattering in various
550  * printk like tracing in the code, a developer can quickly see
551  * where problems are occurring.
552  *
553  * This is intended as a debugging tool for the developer only.
554  * Please refrain from leaving trace_printks scattered around in
555  * your code. (Extra memory is used for special buffers that are
556  * allocated when trace_printk() is used.)
557  *
558  * A little optimization trick is done here. If there's only one
559  * argument, there's no need to scan the string for printf formats.
560  * The trace_puts() will suffice. But how can we take advantage of
561  * using trace_puts() when trace_printk() has only one argument?
562  * By stringifying the args and checking the size we can tell
563  * whether or not there are args. __stringify((__VA_ARGS__)) will
564  * turn into "()\0" with a size of 3 when there are no args, anything
565  * else will be bigger. All we need to do is define a string to this,
566  * and then take its size and compare to 3. If it's bigger, use
567  * do_trace_printk() otherwise, optimize it to trace_puts(). Then just
568  * let gcc optimize the rest.
569  */
570 
571 #define trace_printk(fmt, ...)                          \
572 do {                                                    \
573         char _______STR[] = __stringify((__VA_ARGS__)); \
574         if (sizeof(_______STR) > 3)                     \
575                 do_trace_printk(fmt, ##__VA_ARGS__);    \
576         else                                            \
577                 trace_puts(fmt);                        \
578 } while (0)
579 
580 #define do_trace_printk(fmt, args...)                                   \
581 do {                                                                    \
582         static const char *trace_printk_fmt __used                      \
583                 __section("__trace_printk_fmt") =                       \
584                 __builtin_constant_p(fmt) ? fmt : NULL;                 \
585                                                                         \
586         __trace_printk_check_format(fmt, ##args);                       \
587                                                                         \
588         if (__builtin_constant_p(fmt))                                  \
589                 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args);   \
590         else                                                            \
591                 __trace_printk(_THIS_IP_, fmt, ##args);                 \
592 } while (0)
593 
594 extern __printf(2, 3)
595 int __trace_bprintk(unsigned long ip, const char *fmt, ...);
596 
597 extern __printf(2, 3)
598 int __trace_printk(unsigned long ip, const char *fmt, ...);
599 
600 /**
601  * trace_puts - write a string into the ftrace buffer
602  * @str: the string to record
603  *
604  * Note: __trace_bputs is an internal function for trace_puts and
605  *       the @ip is passed in via the trace_puts macro.
606  *
607  * This is similar to trace_printk() but is made for those really fast
608  * paths that a developer wants the least amount of "Heisenbug" effects,
609  * where the processing of the print format is still too much.
610  *
611  * This function allows a kernel developer to debug fast path sections
612  * that printk is not appropriate for. By scattering in various
613  * printk like tracing in the code, a developer can quickly see
614  * where problems are occurring.
615  *
616  * This is intended as a debugging tool for the developer only.
617  * Please refrain from leaving trace_puts scattered around in
618  * your code. (Extra memory is used for special buffers that are
619  * allocated when trace_puts() is used.)
620  *
621  * Returns: 0 if nothing was written, positive # if string was.
622  *  (1 when __trace_bputs is used, strlen(str) when __trace_puts is used)
623  */
624 
625 #define trace_puts(str) ({                                              \
626         static const char *trace_printk_fmt __used                      \
627                 __section("__trace_printk_fmt") =                       \
628                 __builtin_constant_p(str) ? str : NULL;                 \
629                                                                         \
630         if (__builtin_constant_p(str))                                  \
631                 __trace_bputs(_THIS_IP_, trace_printk_fmt);             \
632         else                                                            \
633                 __trace_puts(_THIS_IP_, str, strlen(str));              \
634 })
635 extern int __trace_bputs(unsigned long ip, const char *str);
636 extern int __trace_puts(unsigned long ip, const char *str, int size);
637 
638 extern void trace_dump_stack(int skip);
639 
640 /*
641  * The double __builtin_constant_p is because gcc will give us an error
642  * if we try to allocate the static variable to fmt if it is not a
643  * constant. Even with the outer if statement.
644  */
645 #define ftrace_vprintk(fmt, vargs)                                      \
646 do {                                                                    \
647         if (__builtin_constant_p(fmt)) {                                \
648                 static const char *trace_printk_fmt __used              \
649                   __section("__trace_printk_fmt") =                     \
650                         __builtin_constant_p(fmt) ? fmt : NULL;         \
651                                                                         \
652                 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs);  \
653         } else                                                          \
654                 __ftrace_vprintk(_THIS_IP_, fmt, vargs);                \
655 } while (0)
656 
657 extern __printf(2, 0) int
658 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
659 
660 extern __printf(2, 0) int
661 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
662 
663 extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
664 #else
665 static inline void tracing_start(void) { }
666 static inline void tracing_stop(void) { }
667 static inline void trace_dump_stack(int skip) { }
668 
669 static inline void tracing_on(void) { }
670 static inline void tracing_off(void) { }
671 static inline int tracing_is_on(void) { return 0; }
672 static inline void tracing_snapshot(void) { }
673 static inline void tracing_snapshot_alloc(void) { }
674 
675 static inline __printf(1, 2)
676 int trace_printk(const char *fmt, ...)
677 {
678         return 0;
679 }
680 static __printf(1, 0) inline int
681 ftrace_vprintk(const char *fmt, va_list ap)
682 {
683         return 0;
684 }
685 static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
686 #endif /* CONFIG_TRACING */
687 
688 /* This counts to 12. Any more, it will return 13th argument. */
689 #define __COUNT_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _n, X...) _n
690 #define COUNT_ARGS(X...) __COUNT_ARGS(, ##X, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
691 
692 #define __CONCAT(a, b) a ## b
693 #define CONCATENATE(a, b) __CONCAT(a, b)
694 
695 /**
696  * container_of - cast a member of a structure out to the containing structure
697  * @ptr:        the pointer to the member.
698  * @type:       the type of the container struct this is embedded in.
699  * @member:     the name of the member within the struct.
700  *
701  */
702 #define container_of(ptr, type, member) ({                              \
703         void *__mptr = (void *)(ptr);                                   \
704         BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) &&   \
705                          !__same_type(*(ptr), void),                    \
706                          "pointer type mismatch in container_of()");    \
707         ((type *)(__mptr - offsetof(type, member))); })
708 
709 /**
710  * container_of_safe - cast a member of a structure out to the containing structure
711  * @ptr:        the pointer to the member.
712  * @type:       the type of the container struct this is embedded in.
713  * @member:     the name of the member within the struct.
714  *
715  * If IS_ERR_OR_NULL(ptr), ptr is returned unchanged.
716  */
717 #define container_of_safe(ptr, type, member) ({                         \
718         void *__mptr = (void *)(ptr);                                   \
719         BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) &&   \
720                          !__same_type(*(ptr), void),                    \
721                          "pointer type mismatch in container_of()");    \
722         IS_ERR_OR_NULL(__mptr) ? ERR_CAST(__mptr) :                     \
723                 ((type *)(__mptr - offsetof(type, member))); })
724 
725 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
726 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
727 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
728 #endif
729 
730 /* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */
731 #define VERIFY_OCTAL_PERMISSIONS(perms)                                         \
732         (BUILD_BUG_ON_ZERO((perms) < 0) +                                       \
733          BUILD_BUG_ON_ZERO((perms) > 0777) +                                    \
734          /* USER_READABLE >= GROUP_READABLE >= OTHER_READABLE */                \
735          BUILD_BUG_ON_ZERO((((perms) >> 6) & 4) < (((perms) >> 3) & 4)) +       \
736          BUILD_BUG_ON_ZERO((((perms) >> 3) & 4) < ((perms) & 4)) +              \
737          /* USER_WRITABLE >= GROUP_WRITABLE */                                  \
738          BUILD_BUG_ON_ZERO((((perms) >> 6) & 2) < (((perms) >> 3) & 2)) +       \
739          /* OTHER_WRITABLE?  Generally considered a bad idea. */                \
740          BUILD_BUG_ON_ZERO((perms) & 2) +                                       \
741          (perms))
742 #endif
743 

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