1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_KERNEL_H
3 #define _LINUX_KERNEL_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/typecheck.h>
15 #include <linux/printk.h>
16 #include <linux/build_bug.h>
17 #include <asm/byteorder.h>
18 #include <asm/div64.h>
19 #include <uapi/linux/kernel.h>
21 #define STACK_MAGIC 0xdeadbeef
24 * REPEAT_BYTE - repeat the value @x multiple times as an unsigned long value
27 * NOTE: @x is not checked for > 0xff; larger values produce odd results.
29 #define REPEAT_BYTE(x) ((~0ul / 0xff) * (x))
31 /* @a is a power of 2 value */
32 #define ALIGN(x, a) __ALIGN_KERNEL((x), (a))
33 #define ALIGN_DOWN(x, a) __ALIGN_KERNEL((x) - ((a) - 1), (a))
34 #define __ALIGN_MASK(x, mask) __ALIGN_KERNEL_MASK((x), (mask))
35 #define PTR_ALIGN(p, a) ((typeof(p))ALIGN((unsigned long)(p), (a)))
36 #define PTR_ALIGN_DOWN(p, a) ((typeof(p))ALIGN_DOWN((unsigned long)(p), (a)))
37 #define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0)
39 /* generic data direction definitions */
44 * ARRAY_SIZE - get the number of elements in array @arr
45 * @arr: array to be sized
47 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
49 #define u64_to_user_ptr(x) ( \
51 typecheck(u64, (x)); \
52 (void __user *)(uintptr_t)(x); \
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.
62 #define __round_mask(x, y) ((__typeof__(x))((y)-1))
64 * round_up - round up to next specified power of 2
65 * @x: the value to round
66 * @y: multiple to round up to (must be a power of 2)
68 * Rounds @x up to next multiple of @y (which must be a power of 2).
69 * To perform arbitrary rounding up, use roundup() below.
71 #define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
73 * round_down - round down to next specified power of 2
74 * @x: the value to round
75 * @y: multiple to round down to (must be a power of 2)
77 * Rounds @x down to next multiple of @y (which must be a power of 2).
78 * To perform arbitrary rounding down, use rounddown() below.
80 #define round_down(x, y) ((x) & ~__round_mask(x, y))
82 #define typeof_member(T, m) typeof(((T*)0)->m)
84 #define DIV_ROUND_UP __KERNEL_DIV_ROUND_UP
86 #define DIV_ROUND_DOWN_ULL(ll, d) \
87 ({ unsigned long long _tmp = (ll); do_div(_tmp, d); _tmp; })
89 #define DIV_ROUND_UP_ULL(ll, d) \
90 DIV_ROUND_DOWN_ULL((unsigned long long)(ll) + (d) - 1, (d))
92 #if BITS_PER_LONG == 32
93 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d)
95 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d)
99 * roundup - round up to the next specified multiple
100 * @x: the value to up
101 * @y: multiple to round up to
103 * Rounds @x up to next multiple of @y. If @y will always be a power
104 * of 2, consider using the faster round_up().
106 #define roundup(x, y) ( \
109 (((x) + (__y - 1)) / __y) * __y; \
113 * rounddown - round down to next specified multiple
114 * @x: the value to round
115 * @y: multiple to round down to
117 * Rounds @x down to next multiple of @y. If @y will always be a power
118 * of 2, consider using the faster round_down().
120 #define rounddown(x, y) ( \
122 typeof(x) __x = (x); \
128 * Divide positive or negative dividend by positive or negative divisor
129 * and round to closest integer. Result is undefined for negative
130 * divisors if the dividend variable type is unsigned and for negative
131 * dividends if the divisor variable type is unsigned.
133 #define DIV_ROUND_CLOSEST(x, divisor)( \
136 typeof(divisor) __d = divisor; \
137 (((typeof(x))-1) > 0 || \
138 ((typeof(divisor))-1) > 0 || \
139 (((__x) > 0) == ((__d) > 0))) ? \
140 (((__x) + ((__d) / 2)) / (__d)) : \
141 (((__x) - ((__d) / 2)) / (__d)); \
145 * Same as above but for u64 dividends. divisor must be a 32-bit
148 #define DIV_ROUND_CLOSEST_ULL(x, divisor)( \
150 typeof(divisor) __d = divisor; \
151 unsigned long long _tmp = (x) + (__d) / 2; \
158 * Multiplies an integer by a fraction, while avoiding unnecessary
159 * overflow or loss of precision.
161 #define mult_frac(x, numer, denom)( \
163 typeof(x) quot = (x) / (denom); \
164 typeof(x) rem = (x) % (denom); \
165 (quot * (numer)) + ((rem * (numer)) / (denom)); \
170 #define _RET_IP_ (unsigned long)__builtin_return_address(0)
171 #define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; })
173 #define sector_div(a, b) do_div(a, b)
176 * upper_32_bits - return bits 32-63 of a number
177 * @n: the number we're accessing
179 * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress
180 * the "right shift count >= width of type" warning when that quantity is
183 #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
186 * lower_32_bits - return bits 0-31 of a number
187 * @n: the number we're accessing
189 #define lower_32_bits(n) ((u32)((n) & 0xffffffff))
195 #ifdef CONFIG_PREEMPT_VOLUNTARY
196 extern int _cond_resched(void);
197 # define might_resched() _cond_resched()
199 # define might_resched() do { } while (0)
202 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
203 extern void ___might_sleep(const char *file, int line, int preempt_offset);
204 extern void __might_sleep(const char *file, int line, int preempt_offset);
205 extern void __cant_sleep(const char *file, int line, int preempt_offset);
208 * might_sleep - annotation for functions that can sleep
210 * this macro will print a stack trace if it is executed in an atomic
211 * context (spinlock, irq-handler, ...). Additional sections where blocking is
212 * not allowed can be annotated with non_block_start() and non_block_end()
215 * This is a useful debugging help to be able to catch problems early and not
216 * be bitten later when the calling function happens to sleep when it is not
219 # define might_sleep() \
220 do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
222 * cant_sleep - annotation for functions that cannot sleep
224 * this macro will print a stack trace if it is executed with preemption enabled
226 # define cant_sleep() \
227 do { __cant_sleep(__FILE__, __LINE__, 0); } while (0)
228 # define sched_annotate_sleep() (current->task_state_change = 0)
230 * non_block_start - annotate the start of section where sleeping is prohibited
232 * This is on behalf of the oom reaper, specifically when it is calling the mmu
233 * notifiers. The problem is that if the notifier were to block on, for example,
234 * mutex_lock() and if the process which holds that mutex were to perform a
235 * sleeping memory allocation, the oom reaper is now blocked on completion of
236 * that memory allocation. Other blocking calls like wait_event() pose similar
239 # define non_block_start() (current->non_block_count++)
241 * non_block_end - annotate the end of section where sleeping is prohibited
243 * Closes a section opened by non_block_start().
245 # define non_block_end() WARN_ON(current->non_block_count-- == 0)
247 static inline void ___might_sleep(const char *file, int line,
248 int preempt_offset) { }
249 static inline void __might_sleep(const char *file, int line,
250 int preempt_offset) { }
251 # define might_sleep() do { might_resched(); } while (0)
252 # define cant_sleep() do { } while (0)
253 # define sched_annotate_sleep() do { } while (0)
254 # define non_block_start() do { } while (0)
255 # define non_block_end() do { } while (0)
258 #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
260 #ifndef CONFIG_PREEMPT_RT
261 # define cant_migrate() cant_sleep()
263 /* Placeholder for now */
264 # define cant_migrate() do { } while (0)
268 * abs - return absolute value of an argument
269 * @x: the value. If it is unsigned type, it is converted to signed type first.
270 * char is treated as if it was signed (regardless of whether it really is)
271 * but the macro's return type is preserved as char.
273 * Return: an absolute value of x.
275 #define abs(x) __abs_choose_expr(x, long long, \
276 __abs_choose_expr(x, long, \
277 __abs_choose_expr(x, int, \
278 __abs_choose_expr(x, short, \
279 __abs_choose_expr(x, char, \
280 __builtin_choose_expr( \
281 __builtin_types_compatible_p(typeof(x), char), \
282 (char)({ signed char __x = (x); __x<0?-__x:__x; }), \
285 #define __abs_choose_expr(x, type, other) __builtin_choose_expr( \
286 __builtin_types_compatible_p(typeof(x), signed type) || \
287 __builtin_types_compatible_p(typeof(x), unsigned type), \
288 ({ signed type __x = (x); __x < 0 ? -__x : __x; }), other)
291 * reciprocal_scale - "scale" a value into range [0, ep_ro)
293 * @ep_ro: right open interval endpoint
295 * Perform a "reciprocal multiplication" in order to "scale" a value into
296 * range [0, @ep_ro), where the upper interval endpoint is right-open.
297 * This is useful, e.g. for accessing a index of an array containing
298 * @ep_ro elements, for example. Think of it as sort of modulus, only that
299 * the result isn't that of modulo. ;) Note that if initial input is a
300 * small value, then result will return 0.
302 * Return: a result based on @val in interval [0, @ep_ro).
304 static inline u32 reciprocal_scale(u32 val, u32 ep_ro)
306 return (u32)(((u64) val * ep_ro) >> 32);
309 #if defined(CONFIG_MMU) && \
310 (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP))
311 #define might_fault() __might_fault(__FILE__, __LINE__)
312 void __might_fault(const char *file, int line);
314 static inline void might_fault(void) { }
317 extern struct atomic_notifier_head panic_notifier_list;
318 extern long (*panic_blink)(int state);
320 void panic(const char *fmt, ...) __noreturn __cold;
321 void nmi_panic(struct pt_regs *regs, const char *msg);
322 extern void oops_enter(void);
323 extern void oops_exit(void);
324 extern bool oops_may_print(void);
325 void do_exit(long error_code) __noreturn;
326 void complete_and_exit(struct completion *, long) __noreturn;
328 /* Internal, do not use. */
329 int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
330 int __must_check _kstrtol(const char *s, unsigned int base, long *res);
332 int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
333 int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
336 * kstrtoul - convert a string to an unsigned long
337 * @s: The start of the string. The string must be null-terminated, and may also
338 * include a single newline before its terminating null. The first character
339 * may also be a plus sign, but not a minus sign.
340 * @base: The number base to use. The maximum supported base is 16. If base is
341 * given as 0, then the base of the string is automatically detected with the
342 * conventional semantics - If it begins with 0x the number will be parsed as a
343 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
344 * parsed as an octal number. Otherwise it will be parsed as a decimal.
345 * @res: Where to write the result of the conversion on success.
347 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
348 * Preferred over simple_strtoul(). Return code must be checked.
350 static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
353 * We want to shortcut function call, but
354 * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
356 if (sizeof(unsigned long) == sizeof(unsigned long long) &&
357 __alignof__(unsigned long) == __alignof__(unsigned long long))
358 return kstrtoull(s, base, (unsigned long long *)res);
360 return _kstrtoul(s, base, res);
364 * kstrtol - convert a string to a long
365 * @s: The start of the string. The string must be null-terminated, and may also
366 * include a single newline before its terminating null. The first character
367 * may also be a plus sign or a minus sign.
368 * @base: The number base to use. The maximum supported base is 16. If base is
369 * given as 0, then the base of the string is automatically detected with the
370 * conventional semantics - If it begins with 0x the number will be parsed as a
371 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
372 * parsed as an octal number. Otherwise it will be parsed as a decimal.
373 * @res: Where to write the result of the conversion on success.
375 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
376 * Preferred over simple_strtol(). Return code must be checked.
378 static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
381 * We want to shortcut function call, but
382 * __builtin_types_compatible_p(long, long long) = 0.
384 if (sizeof(long) == sizeof(long long) &&
385 __alignof__(long) == __alignof__(long long))
386 return kstrtoll(s, base, (long long *)res);
388 return _kstrtol(s, base, res);
391 int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
392 int __must_check kstrtoint(const char *s, unsigned int base, int *res);
394 static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
396 return kstrtoull(s, base, res);
399 static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
401 return kstrtoll(s, base, res);
404 static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
406 return kstrtouint(s, base, res);
409 static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
411 return kstrtoint(s, base, res);
414 int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
415 int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
416 int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
417 int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
418 int __must_check kstrtobool(const char *s, bool *res);
420 int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
421 int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
422 int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
423 int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
424 int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
425 int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
426 int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
427 int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
428 int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
429 int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
430 int __must_check kstrtobool_from_user(const char __user *s, size_t count, bool *res);
432 static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
434 return kstrtoull_from_user(s, count, base, res);
437 static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
439 return kstrtoll_from_user(s, count, base, res);
442 static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
444 return kstrtouint_from_user(s, count, base, res);
447 static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
449 return kstrtoint_from_user(s, count, base, res);
453 * Use kstrto<foo> instead.
455 * NOTE: simple_strto<foo> does not check for the range overflow and,
456 * depending on the input, may give interesting results.
458 * Use these functions if and only if you cannot use kstrto<foo>, because
459 * the conversion ends on the first non-digit character, which may be far
460 * beyond the supported range. It might be useful to parse the strings like
461 * 10x50 or 12:21 without altering original string or temporary buffer in use.
462 * Keep in mind above caveat.
465 extern unsigned long simple_strtoul(const char *,char **,unsigned int);
466 extern long simple_strtol(const char *,char **,unsigned int);
467 extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
468 extern long long simple_strtoll(const char *,char **,unsigned int);
470 extern int num_to_str(char *buf, int size,
471 unsigned long long num, unsigned int width);
473 /* lib/printf utilities */
475 extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
476 extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
477 extern __printf(3, 4)
478 int snprintf(char *buf, size_t size, const char *fmt, ...);
479 extern __printf(3, 0)
480 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
481 extern __printf(3, 4)
482 int scnprintf(char *buf, size_t size, const char *fmt, ...);
483 extern __printf(3, 0)
484 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
485 extern __printf(2, 3) __malloc
486 char *kasprintf(gfp_t gfp, const char *fmt, ...);
487 extern __printf(2, 0) __malloc
488 char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
489 extern __printf(2, 0)
490 const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list args);
493 int sscanf(const char *, const char *, ...);
495 int vsscanf(const char *, const char *, va_list);
497 extern int get_option(char **str, int *pint);
498 extern char *get_options(const char *str, int nints, int *ints);
499 extern unsigned long long memparse(const char *ptr, char **retptr);
500 extern bool parse_option_str(const char *str, const char *option);
501 extern char *next_arg(char *args, char **param, char **val);
503 extern int core_kernel_text(unsigned long addr);
504 extern int init_kernel_text(unsigned long addr);
505 extern int core_kernel_data(unsigned long addr);
506 extern int __kernel_text_address(unsigned long addr);
507 extern int kernel_text_address(unsigned long addr);
508 extern int func_ptr_is_kernel_text(void *ptr);
510 u64 int_pow(u64 base, unsigned int exp);
511 unsigned long int_sqrt(unsigned long);
513 #if BITS_PER_LONG < 64
514 u32 int_sqrt64(u64 x);
516 static inline u32 int_sqrt64(u64 x)
518 return (u32)int_sqrt(x);
523 extern unsigned int sysctl_oops_all_cpu_backtrace;
525 #define sysctl_oops_all_cpu_backtrace 0
526 #endif /* CONFIG_SMP */
528 extern void bust_spinlocks(int yes);
529 extern int panic_timeout;
530 extern unsigned long panic_print;
531 extern int panic_on_oops;
532 extern int panic_on_unrecovered_nmi;
533 extern int panic_on_io_nmi;
534 extern int panic_on_warn;
535 extern unsigned long panic_on_taint;
536 extern bool panic_on_taint_nousertaint;
537 extern int sysctl_panic_on_rcu_stall;
538 extern int sysctl_panic_on_stackoverflow;
540 extern bool crash_kexec_post_notifiers;
543 * panic_cpu is used for synchronizing panic() and crash_kexec() execution. It
544 * holds a CPU number which is executing panic() currently. A value of
545 * PANIC_CPU_INVALID means no CPU has entered panic() or crash_kexec().
547 extern atomic_t panic_cpu;
548 #define PANIC_CPU_INVALID -1
551 * Only to be used by arch init code. If the user over-wrote the default
552 * CONFIG_PANIC_TIMEOUT, honor it.
554 static inline void set_arch_panic_timeout(int timeout, int arch_default_timeout)
556 if (panic_timeout == arch_default_timeout)
557 panic_timeout = timeout;
559 extern const char *print_tainted(void);
562 LOCKDEP_NOW_UNRELIABLE
564 extern void add_taint(unsigned flag, enum lockdep_ok);
565 extern int test_taint(unsigned flag);
566 extern unsigned long get_taint(void);
567 extern int root_mountflags;
569 extern bool early_boot_irqs_disabled;
572 * Values used for system_state. Ordering of the states must not be changed
573 * as code checks for <, <=, >, >= STATE.
575 extern enum system_states {
585 /* This cannot be an enum because some may be used in assembly source. */
586 #define TAINT_PROPRIETARY_MODULE 0
587 #define TAINT_FORCED_MODULE 1
588 #define TAINT_CPU_OUT_OF_SPEC 2
589 #define TAINT_FORCED_RMMOD 3
590 #define TAINT_MACHINE_CHECK 4
591 #define TAINT_BAD_PAGE 5
594 #define TAINT_OVERRIDDEN_ACPI_TABLE 8
596 #define TAINT_CRAP 10
597 #define TAINT_FIRMWARE_WORKAROUND 11
598 #define TAINT_OOT_MODULE 12
599 #define TAINT_UNSIGNED_MODULE 13
600 #define TAINT_SOFTLOCKUP 14
601 #define TAINT_LIVEPATCH 15
603 #define TAINT_RANDSTRUCT 17
604 #define TAINT_FLAGS_COUNT 18
605 #define TAINT_FLAGS_MAX ((1UL << TAINT_FLAGS_COUNT) - 1)
608 char c_true; /* character printed when tainted */
609 char c_false; /* character printed when not tainted */
610 bool module; /* also show as a per-module taint flag */
613 extern const struct taint_flag taint_flags[TAINT_FLAGS_COUNT];
615 extern const char hex_asc[];
616 #define hex_asc_lo(x) hex_asc[((x) & 0x0f)]
617 #define hex_asc_hi(x) hex_asc[((x) & 0xf0) >> 4]
619 static inline char *hex_byte_pack(char *buf, u8 byte)
621 *buf++ = hex_asc_hi(byte);
622 *buf++ = hex_asc_lo(byte);
626 extern const char hex_asc_upper[];
627 #define hex_asc_upper_lo(x) hex_asc_upper[((x) & 0x0f)]
628 #define hex_asc_upper_hi(x) hex_asc_upper[((x) & 0xf0) >> 4]
630 static inline char *hex_byte_pack_upper(char *buf, u8 byte)
632 *buf++ = hex_asc_upper_hi(byte);
633 *buf++ = hex_asc_upper_lo(byte);
637 extern int hex_to_bin(char ch);
638 extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
639 extern char *bin2hex(char *dst, const void *src, size_t count);
641 bool mac_pton(const char *s, u8 *mac);
644 * General tracing related utility functions - trace_printk(),
645 * tracing_on/tracing_off and tracing_start()/tracing_stop
647 * Use tracing_on/tracing_off when you want to quickly turn on or off
648 * tracing. It simply enables or disables the recording of the trace events.
649 * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
650 * file, which gives a means for the kernel and userspace to interact.
651 * Place a tracing_off() in the kernel where you want tracing to end.
652 * From user space, examine the trace, and then echo 1 > tracing_on
653 * to continue tracing.
655 * tracing_stop/tracing_start has slightly more overhead. It is used
656 * by things like suspend to ram where disabling the recording of the
657 * trace is not enough, but tracing must actually stop because things
658 * like calling smp_processor_id() may crash the system.
660 * Most likely, you want to use tracing_on/tracing_off.
663 enum ftrace_dump_mode {
669 #ifdef CONFIG_TRACING
670 void tracing_on(void);
671 void tracing_off(void);
672 int tracing_is_on(void);
673 void tracing_snapshot(void);
674 void tracing_snapshot_alloc(void);
676 extern void tracing_start(void);
677 extern void tracing_stop(void);
679 static inline __printf(1, 2)
680 void ____trace_printk_check_format(const char *fmt, ...)
683 #define __trace_printk_check_format(fmt, args...) \
686 ____trace_printk_check_format(fmt, ##args); \
690 * trace_printk - printf formatting in the ftrace buffer
691 * @fmt: the printf format for printing
693 * Note: __trace_printk is an internal function for trace_printk() and
694 * the @ip is passed in via the trace_printk() macro.
696 * This function allows a kernel developer to debug fast path sections
697 * that printk is not appropriate for. By scattering in various
698 * printk like tracing in the code, a developer can quickly see
699 * where problems are occurring.
701 * This is intended as a debugging tool for the developer only.
702 * Please refrain from leaving trace_printks scattered around in
703 * your code. (Extra memory is used for special buffers that are
704 * allocated when trace_printk() is used.)
706 * A little optimization trick is done here. If there's only one
707 * argument, there's no need to scan the string for printf formats.
708 * The trace_puts() will suffice. But how can we take advantage of
709 * using trace_puts() when trace_printk() has only one argument?
710 * By stringifying the args and checking the size we can tell
711 * whether or not there are args. __stringify((__VA_ARGS__)) will
712 * turn into "()\0" with a size of 3 when there are no args, anything
713 * else will be bigger. All we need to do is define a string to this,
714 * and then take its size and compare to 3. If it's bigger, use
715 * do_trace_printk() otherwise, optimize it to trace_puts(). Then just
716 * let gcc optimize the rest.
719 #define trace_printk(fmt, ...) \
721 char _______STR[] = __stringify((__VA_ARGS__)); \
722 if (sizeof(_______STR) > 3) \
723 do_trace_printk(fmt, ##__VA_ARGS__); \
728 #define do_trace_printk(fmt, args...) \
730 static const char *trace_printk_fmt __used \
731 __attribute__((section("__trace_printk_fmt"))) = \
732 __builtin_constant_p(fmt) ? fmt : NULL; \
734 __trace_printk_check_format(fmt, ##args); \
736 if (__builtin_constant_p(fmt)) \
737 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \
739 __trace_printk(_THIS_IP_, fmt, ##args); \
742 extern __printf(2, 3)
743 int __trace_bprintk(unsigned long ip, const char *fmt, ...);
745 extern __printf(2, 3)
746 int __trace_printk(unsigned long ip, const char *fmt, ...);
749 * trace_puts - write a string into the ftrace buffer
750 * @str: the string to record
752 * Note: __trace_bputs is an internal function for trace_puts and
753 * the @ip is passed in via the trace_puts macro.
755 * This is similar to trace_printk() but is made for those really fast
756 * paths that a developer wants the least amount of "Heisenbug" effects,
757 * where the processing of the print format is still too much.
759 * This function allows a kernel developer to debug fast path sections
760 * that printk is not appropriate for. By scattering in various
761 * printk like tracing in the code, a developer can quickly see
762 * where problems are occurring.
764 * This is intended as a debugging tool for the developer only.
765 * Please refrain from leaving trace_puts scattered around in
766 * your code. (Extra memory is used for special buffers that are
767 * allocated when trace_puts() is used.)
769 * Returns: 0 if nothing was written, positive # if string was.
770 * (1 when __trace_bputs is used, strlen(str) when __trace_puts is used)
773 #define trace_puts(str) ({ \
774 static const char *trace_printk_fmt __used \
775 __attribute__((section("__trace_printk_fmt"))) = \
776 __builtin_constant_p(str) ? str : NULL; \
778 if (__builtin_constant_p(str)) \
779 __trace_bputs(_THIS_IP_, trace_printk_fmt); \
781 __trace_puts(_THIS_IP_, str, strlen(str)); \
783 extern int __trace_bputs(unsigned long ip, const char *str);
784 extern int __trace_puts(unsigned long ip, const char *str, int size);
786 extern void trace_dump_stack(int skip);
789 * The double __builtin_constant_p is because gcc will give us an error
790 * if we try to allocate the static variable to fmt if it is not a
791 * constant. Even with the outer if statement.
793 #define ftrace_vprintk(fmt, vargs) \
795 if (__builtin_constant_p(fmt)) { \
796 static const char *trace_printk_fmt __used \
797 __attribute__((section("__trace_printk_fmt"))) = \
798 __builtin_constant_p(fmt) ? fmt : NULL; \
800 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs); \
802 __ftrace_vprintk(_THIS_IP_, fmt, vargs); \
805 extern __printf(2, 0) int
806 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
808 extern __printf(2, 0) int
809 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
811 extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
813 static inline void tracing_start(void) { }
814 static inline void tracing_stop(void) { }
815 static inline void trace_dump_stack(int skip) { }
817 static inline void tracing_on(void) { }
818 static inline void tracing_off(void) { }
819 static inline int tracing_is_on(void) { return 0; }
820 static inline void tracing_snapshot(void) { }
821 static inline void tracing_snapshot_alloc(void) { }
823 static inline __printf(1, 2)
824 int trace_printk(const char *fmt, ...)
828 static __printf(1, 0) inline int
829 ftrace_vprintk(const char *fmt, va_list ap)
833 static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
834 #endif /* CONFIG_TRACING */
837 * min()/max()/clamp() macros must accomplish three things:
839 * - avoid multiple evaluations of the arguments (so side-effects like
840 * "x++" happen only once) when non-constant.
841 * - perform strict type-checking (to generate warnings instead of
842 * nasty runtime surprises). See the "unnecessary" pointer comparison
844 * - retain result as a constant expressions when called with only
845 * constant expressions (to avoid tripping VLA warnings in stack
848 #define __typecheck(x, y) \
849 (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
852 * This returns a constant expression while determining if an argument is
853 * a constant expression, most importantly without evaluating the argument.
854 * Glory to Martin Uecker <Martin.Uecker@med.uni-goettingen.de>
856 #define __is_constexpr(x) \
857 (sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8)))
859 #define __no_side_effects(x, y) \
860 (__is_constexpr(x) && __is_constexpr(y))
862 #define __safe_cmp(x, y) \
863 (__typecheck(x, y) && __no_side_effects(x, y))
865 #define __cmp(x, y, op) ((x) op (y) ? (x) : (y))
867 #define __cmp_once(x, y, unique_x, unique_y, op) ({ \
868 typeof(x) unique_x = (x); \
869 typeof(y) unique_y = (y); \
870 __cmp(unique_x, unique_y, op); })
872 #define __careful_cmp(x, y, op) \
873 __builtin_choose_expr(__safe_cmp(x, y), \
875 __cmp_once(x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y), op))
878 * min - return minimum of two values of the same or compatible types
882 #define min(x, y) __careful_cmp(x, y, <)
885 * max - return maximum of two values of the same or compatible types
889 #define max(x, y) __careful_cmp(x, y, >)
892 * min3 - return minimum of three values
897 #define min3(x, y, z) min((typeof(x))min(x, y), z)
900 * max3 - return maximum of three values
905 #define max3(x, y, z) max((typeof(x))max(x, y), z)
908 * min_not_zero - return the minimum that is _not_ zero, unless both are zero
912 #define min_not_zero(x, y) ({ \
913 typeof(x) __x = (x); \
914 typeof(y) __y = (y); \
915 __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
918 * clamp - return a value clamped to a given range with strict typechecking
919 * @val: current value
920 * @lo: lowest allowable value
921 * @hi: highest allowable value
923 * This macro does strict typechecking of @lo/@hi to make sure they are of the
924 * same type as @val. See the unnecessary pointer comparisons.
926 #define clamp(val, lo, hi) min((typeof(val))max(val, lo), hi)
929 * ..and if you can't take the strict
930 * types, you can specify one yourself.
932 * Or not use min/max/clamp at all, of course.
936 * min_t - return minimum of two values, using the specified type
937 * @type: data type to use
941 #define min_t(type, x, y) __careful_cmp((type)(x), (type)(y), <)
944 * max_t - return maximum of two values, using the specified type
945 * @type: data type to use
949 #define max_t(type, x, y) __careful_cmp((type)(x), (type)(y), >)
952 * clamp_t - return a value clamped to a given range using a given type
953 * @type: the type of variable to use
954 * @val: current value
955 * @lo: minimum allowable value
956 * @hi: maximum allowable value
958 * This macro does no typechecking and uses temporary variables of type
959 * @type to make all the comparisons.
961 #define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi)
964 * clamp_val - return a value clamped to a given range using val's type
965 * @val: current value
966 * @lo: minimum allowable value
967 * @hi: maximum allowable value
969 * This macro does no typechecking and uses temporary variables of whatever
970 * type the input argument @val is. This is useful when @val is an unsigned
971 * type and @lo and @hi are literals that will otherwise be assigned a signed
974 #define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)
978 * swap - swap values of @a and @b
983 do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
985 /* This counts to 12. Any more, it will return 13th argument. */
986 #define __COUNT_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _n, X...) _n
987 #define COUNT_ARGS(X...) __COUNT_ARGS(, ##X, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
989 #define __CONCAT(a, b) a ## b
990 #define CONCATENATE(a, b) __CONCAT(a, b)
993 * container_of - cast a member of a structure out to the containing structure
994 * @ptr: the pointer to the member.
995 * @type: the type of the container struct this is embedded in.
996 * @member: the name of the member within the struct.
999 #define container_of(ptr, type, member) ({ \
1000 void *__mptr = (void *)(ptr); \
1001 BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
1002 !__same_type(*(ptr), void), \
1003 "pointer type mismatch in container_of()"); \
1004 ((type *)(__mptr - offsetof(type, member))); })
1007 * container_of_safe - cast a member of a structure out to the containing structure
1008 * @ptr: the pointer to the member.
1009 * @type: the type of the container struct this is embedded in.
1010 * @member: the name of the member within the struct.
1012 * If IS_ERR_OR_NULL(ptr), ptr is returned unchanged.
1014 #define container_of_safe(ptr, type, member) ({ \
1015 void *__mptr = (void *)(ptr); \
1016 BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
1017 !__same_type(*(ptr), void), \
1018 "pointer type mismatch in container_of()"); \
1019 IS_ERR_OR_NULL(__mptr) ? ERR_CAST(__mptr) : \
1020 ((type *)(__mptr - offsetof(type, member))); })
1022 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
1023 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
1024 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
1027 /* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */
1028 #define VERIFY_OCTAL_PERMISSIONS(perms) \
1029 (BUILD_BUG_ON_ZERO((perms) < 0) + \
1030 BUILD_BUG_ON_ZERO((perms) > 0777) + \
1031 /* USER_READABLE >= GROUP_READABLE >= OTHER_READABLE */ \
1032 BUILD_BUG_ON_ZERO((((perms) >> 6) & 4) < (((perms) >> 3) & 4)) + \
1033 BUILD_BUG_ON_ZERO((((perms) >> 3) & 4) < ((perms) & 4)) + \
1034 /* USER_WRITABLE >= GROUP_WRITABLE */ \
1035 BUILD_BUG_ON_ZERO((((perms) >> 6) & 2) < (((perms) >> 3) & 2)) + \
1036 /* OTHER_WRITABLE? Generally considered a bad idea. */ \
1037 BUILD_BUG_ON_ZERO((perms) & 2) + \