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>
20 #include <asm/div64.h>
22 #define STACK_MAGIC 0xdeadbeef
25 * REPEAT_BYTE - repeat the value @x multiple times as an unsigned long value
28 * NOTE: @x is not checked for > 0xff; larger values produce odd results.
30 #define REPEAT_BYTE(x) ((~0ul / 0xff) * (x))
32 /* @a is a power of 2 value */
33 #define ALIGN(x, a) __ALIGN_KERNEL((x), (a))
34 #define ALIGN_DOWN(x, a) __ALIGN_KERNEL((x) - ((a) - 1), (a))
35 #define __ALIGN_MASK(x, mask) __ALIGN_KERNEL_MASK((x), (mask))
36 #define PTR_ALIGN(p, a) ((typeof(p))ALIGN((unsigned long)(p), (a)))
37 #define PTR_ALIGN_DOWN(p, a) ((typeof(p))ALIGN_DOWN((unsigned long)(p), (a)))
38 #define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0)
40 /* generic data direction definitions */
45 * ARRAY_SIZE - get the number of elements in array @arr
46 * @arr: array to be sized
48 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
50 #define u64_to_user_ptr(x) ( \
52 typecheck(u64, (x)); \
53 (void __user *)(uintptr_t)(x); \
58 * This looks more complex than it should be. But we need to
59 * get the type for the ~ right in round_down (it needs to be
60 * as wide as the result!), and we want to evaluate the macro
61 * arguments just once each.
63 #define __round_mask(x, y) ((__typeof__(x))((y)-1))
65 * round_up - round up to next specified power of 2
66 * @x: the value to round
67 * @y: multiple to round up to (must be a power of 2)
69 * Rounds @x up to next multiple of @y (which must be a power of 2).
70 * To perform arbitrary rounding up, use roundup() below.
72 #define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
74 * round_down - round down to next specified power of 2
75 * @x: the value to round
76 * @y: multiple to round down to (must be a power of 2)
78 * Rounds @x down to next multiple of @y (which must be a power of 2).
79 * To perform arbitrary rounding down, use rounddown() below.
81 #define round_down(x, y) ((x) & ~__round_mask(x, y))
83 #define typeof_member(T, m) typeof(((T*)0)->m)
85 #define DIV_ROUND_UP __KERNEL_DIV_ROUND_UP
87 #define DIV_ROUND_DOWN_ULL(ll, d) \
88 ({ unsigned long long _tmp = (ll); do_div(_tmp, d); _tmp; })
90 #define DIV_ROUND_UP_ULL(ll, d) \
91 DIV_ROUND_DOWN_ULL((unsigned long long)(ll) + (d) - 1, (d))
93 #if BITS_PER_LONG == 32
94 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d)
96 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d)
100 * roundup - round up to the next specified multiple
101 * @x: the value to up
102 * @y: multiple to round up to
104 * Rounds @x up to next multiple of @y. If @y will always be a power
105 * of 2, consider using the faster round_up().
107 #define roundup(x, y) ( \
110 (((x) + (__y - 1)) / __y) * __y; \
114 * rounddown - round down to next specified multiple
115 * @x: the value to round
116 * @y: multiple to round down to
118 * Rounds @x down to next multiple of @y. If @y will always be a power
119 * of 2, consider using the faster round_down().
121 #define rounddown(x, y) ( \
123 typeof(x) __x = (x); \
129 * Divide positive or negative dividend by positive or negative divisor
130 * and round to closest integer. Result is undefined for negative
131 * divisors if the dividend variable type is unsigned and for negative
132 * dividends if the divisor variable type is unsigned.
134 #define DIV_ROUND_CLOSEST(x, divisor)( \
137 typeof(divisor) __d = divisor; \
138 (((typeof(x))-1) > 0 || \
139 ((typeof(divisor))-1) > 0 || \
140 (((__x) > 0) == ((__d) > 0))) ? \
141 (((__x) + ((__d) / 2)) / (__d)) : \
142 (((__x) - ((__d) / 2)) / (__d)); \
146 * Same as above but for u64 dividends. divisor must be a 32-bit
149 #define DIV_ROUND_CLOSEST_ULL(x, divisor)( \
151 typeof(divisor) __d = divisor; \
152 unsigned long long _tmp = (x) + (__d) / 2; \
159 * Multiplies an integer by a fraction, while avoiding unnecessary
160 * overflow or loss of precision.
162 #define mult_frac(x, numer, denom)( \
164 typeof(x) quot = (x) / (denom); \
165 typeof(x) rem = (x) % (denom); \
166 (quot * (numer)) + ((rem * (numer)) / (denom)); \
171 #define _RET_IP_ (unsigned long)__builtin_return_address(0)
172 #define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; })
174 #define sector_div(a, b) do_div(a, b)
177 * upper_32_bits - return bits 32-63 of a number
178 * @n: the number we're accessing
180 * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress
181 * the "right shift count >= width of type" warning when that quantity is
184 #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
187 * lower_32_bits - return bits 0-31 of a number
188 * @n: the number we're accessing
190 #define lower_32_bits(n) ((u32)(n))
196 #ifdef CONFIG_PREEMPT_VOLUNTARY
197 extern int _cond_resched(void);
198 # define might_resched() _cond_resched()
200 # define might_resched() do { } while (0)
203 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
204 extern void ___might_sleep(const char *file, int line, int preempt_offset);
205 extern void __might_sleep(const char *file, int line, int preempt_offset);
206 extern void __cant_sleep(const char *file, int line, int preempt_offset);
209 * might_sleep - annotation for functions that can sleep
211 * this macro will print a stack trace if it is executed in an atomic
212 * context (spinlock, irq-handler, ...). Additional sections where blocking is
213 * not allowed can be annotated with non_block_start() and non_block_end()
216 * This is a useful debugging help to be able to catch problems early and not
217 * be bitten later when the calling function happens to sleep when it is not
220 # define might_sleep() \
221 do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
223 * cant_sleep - annotation for functions that cannot sleep
225 * this macro will print a stack trace if it is executed with preemption enabled
227 # define cant_sleep() \
228 do { __cant_sleep(__FILE__, __LINE__, 0); } while (0)
229 # define sched_annotate_sleep() (current->task_state_change = 0)
231 * non_block_start - annotate the start of section where sleeping is prohibited
233 * This is on behalf of the oom reaper, specifically when it is calling the mmu
234 * notifiers. The problem is that if the notifier were to block on, for example,
235 * mutex_lock() and if the process which holds that mutex were to perform a
236 * sleeping memory allocation, the oom reaper is now blocked on completion of
237 * that memory allocation. Other blocking calls like wait_event() pose similar
240 # define non_block_start() (current->non_block_count++)
242 * non_block_end - annotate the end of section where sleeping is prohibited
244 * Closes a section opened by non_block_start().
246 # define non_block_end() WARN_ON(current->non_block_count-- == 0)
248 static inline void ___might_sleep(const char *file, int line,
249 int preempt_offset) { }
250 static inline void __might_sleep(const char *file, int line,
251 int preempt_offset) { }
252 # define might_sleep() do { might_resched(); } while (0)
253 # define cant_sleep() do { } while (0)
254 # define sched_annotate_sleep() do { } while (0)
255 # define non_block_start() do { } while (0)
256 # define non_block_end() do { } while (0)
259 #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
261 #ifndef CONFIG_PREEMPT_RT
262 # define cant_migrate() cant_sleep()
264 /* Placeholder for now */
265 # define cant_migrate() do { } while (0)
269 * abs - return absolute value of an argument
270 * @x: the value. If it is unsigned type, it is converted to signed type first.
271 * char is treated as if it was signed (regardless of whether it really is)
272 * but the macro's return type is preserved as char.
274 * Return: an absolute value of x.
276 #define abs(x) __abs_choose_expr(x, long long, \
277 __abs_choose_expr(x, long, \
278 __abs_choose_expr(x, int, \
279 __abs_choose_expr(x, short, \
280 __abs_choose_expr(x, char, \
281 __builtin_choose_expr( \
282 __builtin_types_compatible_p(typeof(x), char), \
283 (char)({ signed char __x = (x); __x<0?-__x:__x; }), \
286 #define __abs_choose_expr(x, type, other) __builtin_choose_expr( \
287 __builtin_types_compatible_p(typeof(x), signed type) || \
288 __builtin_types_compatible_p(typeof(x), unsigned type), \
289 ({ signed type __x = (x); __x < 0 ? -__x : __x; }), other)
292 * reciprocal_scale - "scale" a value into range [0, ep_ro)
294 * @ep_ro: right open interval endpoint
296 * Perform a "reciprocal multiplication" in order to "scale" a value into
297 * range [0, @ep_ro), where the upper interval endpoint is right-open.
298 * This is useful, e.g. for accessing a index of an array containing
299 * @ep_ro elements, for example. Think of it as sort of modulus, only that
300 * the result isn't that of modulo. ;) Note that if initial input is a
301 * small value, then result will return 0.
303 * Return: a result based on @val in interval [0, @ep_ro).
305 static inline u32 reciprocal_scale(u32 val, u32 ep_ro)
307 return (u32)(((u64) val * ep_ro) >> 32);
310 #if defined(CONFIG_MMU) && \
311 (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP))
312 #define might_fault() __might_fault(__FILE__, __LINE__)
313 void __might_fault(const char *file, int line);
315 static inline void might_fault(void) { }
318 extern struct atomic_notifier_head panic_notifier_list;
319 extern long (*panic_blink)(int state);
321 void panic(const char *fmt, ...) __noreturn __cold;
322 void nmi_panic(struct pt_regs *regs, const char *msg);
323 extern void oops_enter(void);
324 extern void oops_exit(void);
325 void print_oops_end_marker(void);
326 extern int oops_may_print(void);
327 void do_exit(long error_code) __noreturn;
328 void complete_and_exit(struct completion *, long) __noreturn;
330 /* Internal, do not use. */
331 int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
332 int __must_check _kstrtol(const char *s, unsigned int base, long *res);
334 int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
335 int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
338 * kstrtoul - convert a string to an unsigned long
339 * @s: The start of the string. The string must be null-terminated, and may also
340 * include a single newline before its terminating null. The first character
341 * may also be a plus sign, but not a minus sign.
342 * @base: The number base to use. The maximum supported base is 16. If base is
343 * given as 0, then the base of the string is automatically detected with the
344 * conventional semantics - If it begins with 0x the number will be parsed as a
345 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
346 * parsed as an octal number. Otherwise it will be parsed as a decimal.
347 * @res: Where to write the result of the conversion on success.
349 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
350 * Used as a replacement for the simple_strtoull. Return code must be checked.
352 static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
355 * We want to shortcut function call, but
356 * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
358 if (sizeof(unsigned long) == sizeof(unsigned long long) &&
359 __alignof__(unsigned long) == __alignof__(unsigned long long))
360 return kstrtoull(s, base, (unsigned long long *)res);
362 return _kstrtoul(s, base, res);
366 * kstrtol - convert a string to a long
367 * @s: The start of the string. The string must be null-terminated, and may also
368 * include a single newline before its terminating null. The first character
369 * may also be a plus sign or a minus sign.
370 * @base: The number base to use. The maximum supported base is 16. If base is
371 * given as 0, then the base of the string is automatically detected with the
372 * conventional semantics - If it begins with 0x the number will be parsed as a
373 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
374 * parsed as an octal number. Otherwise it will be parsed as a decimal.
375 * @res: Where to write the result of the conversion on success.
377 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
378 * Used as a replacement for the simple_strtoull. Return code must be checked.
380 static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
383 * We want to shortcut function call, but
384 * __builtin_types_compatible_p(long, long long) = 0.
386 if (sizeof(long) == sizeof(long long) &&
387 __alignof__(long) == __alignof__(long long))
388 return kstrtoll(s, base, (long long *)res);
390 return _kstrtol(s, base, res);
393 int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
394 int __must_check kstrtoint(const char *s, unsigned int base, int *res);
396 static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
398 return kstrtoull(s, base, res);
401 static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
403 return kstrtoll(s, base, res);
406 static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
408 return kstrtouint(s, base, res);
411 static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
413 return kstrtoint(s, base, res);
416 int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
417 int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
418 int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
419 int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
420 int __must_check kstrtobool(const char *s, bool *res);
422 int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
423 int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
424 int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
425 int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
426 int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
427 int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
428 int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
429 int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
430 int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
431 int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
432 int __must_check kstrtobool_from_user(const char __user *s, size_t count, bool *res);
434 static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
436 return kstrtoull_from_user(s, count, base, res);
439 static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
441 return kstrtoll_from_user(s, count, base, res);
444 static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
446 return kstrtouint_from_user(s, count, base, res);
449 static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
451 return kstrtoint_from_user(s, count, base, res);
455 * Use kstrto<foo> instead.
457 * NOTE: simple_strto<foo> does not check for the range overflow and,
458 * depending on the input, may give interesting results.
460 * Use these functions if and only if you cannot use kstrto<foo>, because
461 * the conversion ends on the first non-digit character, which may be far
462 * beyond the supported range. It might be useful to parse the strings like
463 * 10x50 or 12:21 without altering original string or temporary buffer in use.
464 * Keep in mind above caveat.
467 extern unsigned long simple_strtoul(const char *,char **,unsigned int);
468 extern long simple_strtol(const char *,char **,unsigned int);
469 extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
470 extern long long simple_strtoll(const char *,char **,unsigned int);
472 extern int num_to_str(char *buf, int size,
473 unsigned long long num, unsigned int width);
475 /* lib/printf utilities */
477 extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
478 extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
479 extern __printf(3, 4)
480 int snprintf(char *buf, size_t size, const char *fmt, ...);
481 extern __printf(3, 0)
482 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
483 extern __printf(3, 4)
484 int scnprintf(char *buf, size_t size, const char *fmt, ...);
485 extern __printf(3, 0)
486 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
487 extern __printf(2, 3) __malloc
488 char *kasprintf(gfp_t gfp, const char *fmt, ...);
489 extern __printf(2, 0) __malloc
490 char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
491 extern __printf(2, 0)
492 const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list args);
495 int sscanf(const char *, const char *, ...);
497 int vsscanf(const char *, const char *, va_list);
499 extern int get_option(char **str, int *pint);
500 extern char *get_options(const char *str, int nints, int *ints);
501 extern unsigned long long memparse(const char *ptr, char **retptr);
502 extern bool parse_option_str(const char *str, const char *option);
503 extern char *next_arg(char *args, char **param, char **val);
505 extern int core_kernel_text(unsigned long addr);
506 extern int init_kernel_text(unsigned long addr);
507 extern int core_kernel_data(unsigned long addr);
508 extern int __kernel_text_address(unsigned long addr);
509 extern int kernel_text_address(unsigned long addr);
510 extern int func_ptr_is_kernel_text(void *ptr);
512 u64 int_pow(u64 base, unsigned int exp);
513 unsigned long int_sqrt(unsigned long);
515 #if BITS_PER_LONG < 64
516 u32 int_sqrt64(u64 x);
518 static inline u32 int_sqrt64(u64 x)
520 return (u32)int_sqrt(x);
525 extern unsigned int sysctl_oops_all_cpu_backtrace;
527 #define sysctl_oops_all_cpu_backtrace 0
528 #endif /* CONFIG_SMP */
530 extern void bust_spinlocks(int yes);
531 extern int oops_in_progress; /* If set, an oops, panic(), BUG() or die() is in progress */
532 extern int panic_timeout;
533 extern unsigned long panic_print;
534 extern int panic_on_oops;
535 extern int panic_on_unrecovered_nmi;
536 extern int panic_on_io_nmi;
537 extern int panic_on_warn;
538 extern unsigned long panic_on_taint;
539 extern bool panic_on_taint_nousertaint;
540 extern int sysctl_panic_on_rcu_stall;
541 extern int sysctl_panic_on_stackoverflow;
543 extern bool crash_kexec_post_notifiers;
546 * panic_cpu is used for synchronizing panic() and crash_kexec() execution. It
547 * holds a CPU number which is executing panic() currently. A value of
548 * PANIC_CPU_INVALID means no CPU has entered panic() or crash_kexec().
550 extern atomic_t panic_cpu;
551 #define PANIC_CPU_INVALID -1
554 * Only to be used by arch init code. If the user over-wrote the default
555 * CONFIG_PANIC_TIMEOUT, honor it.
557 static inline void set_arch_panic_timeout(int timeout, int arch_default_timeout)
559 if (panic_timeout == arch_default_timeout)
560 panic_timeout = timeout;
562 extern const char *print_tainted(void);
565 LOCKDEP_NOW_UNRELIABLE
567 extern void add_taint(unsigned flag, enum lockdep_ok);
568 extern int test_taint(unsigned flag);
569 extern unsigned long get_taint(void);
570 extern int root_mountflags;
572 extern bool early_boot_irqs_disabled;
575 * Values used for system_state. Ordering of the states must not be changed
576 * as code checks for <, <=, >, >= STATE.
578 extern enum system_states {
588 /* This cannot be an enum because some may be used in assembly source. */
589 #define TAINT_PROPRIETARY_MODULE 0
590 #define TAINT_FORCED_MODULE 1
591 #define TAINT_CPU_OUT_OF_SPEC 2
592 #define TAINT_FORCED_RMMOD 3
593 #define TAINT_MACHINE_CHECK 4
594 #define TAINT_BAD_PAGE 5
597 #define TAINT_OVERRIDDEN_ACPI_TABLE 8
599 #define TAINT_CRAP 10
600 #define TAINT_FIRMWARE_WORKAROUND 11
601 #define TAINT_OOT_MODULE 12
602 #define TAINT_UNSIGNED_MODULE 13
603 #define TAINT_SOFTLOCKUP 14
604 #define TAINT_LIVEPATCH 15
606 #define TAINT_RANDSTRUCT 17
607 #define TAINT_FLAGS_COUNT 18
608 #define TAINT_FLAGS_MAX ((1UL << TAINT_FLAGS_COUNT) - 1)
611 char c_true; /* character printed when tainted */
612 char c_false; /* character printed when not tainted */
613 bool module; /* also show as a per-module taint flag */
616 extern const struct taint_flag taint_flags[TAINT_FLAGS_COUNT];
618 extern const char hex_asc[];
619 #define hex_asc_lo(x) hex_asc[((x) & 0x0f)]
620 #define hex_asc_hi(x) hex_asc[((x) & 0xf0) >> 4]
622 static inline char *hex_byte_pack(char *buf, u8 byte)
624 *buf++ = hex_asc_hi(byte);
625 *buf++ = hex_asc_lo(byte);
629 extern const char hex_asc_upper[];
630 #define hex_asc_upper_lo(x) hex_asc_upper[((x) & 0x0f)]
631 #define hex_asc_upper_hi(x) hex_asc_upper[((x) & 0xf0) >> 4]
633 static inline char *hex_byte_pack_upper(char *buf, u8 byte)
635 *buf++ = hex_asc_upper_hi(byte);
636 *buf++ = hex_asc_upper_lo(byte);
640 extern int hex_to_bin(char ch);
641 extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
642 extern char *bin2hex(char *dst, const void *src, size_t count);
644 bool mac_pton(const char *s, u8 *mac);
647 * General tracing related utility functions - trace_printk(),
648 * tracing_on/tracing_off and tracing_start()/tracing_stop
650 * Use tracing_on/tracing_off when you want to quickly turn on or off
651 * tracing. It simply enables or disables the recording of the trace events.
652 * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
653 * file, which gives a means for the kernel and userspace to interact.
654 * Place a tracing_off() in the kernel where you want tracing to end.
655 * From user space, examine the trace, and then echo 1 > tracing_on
656 * to continue tracing.
658 * tracing_stop/tracing_start has slightly more overhead. It is used
659 * by things like suspend to ram where disabling the recording of the
660 * trace is not enough, but tracing must actually stop because things
661 * like calling smp_processor_id() may crash the system.
663 * Most likely, you want to use tracing_on/tracing_off.
666 enum ftrace_dump_mode {
672 #ifdef CONFIG_TRACING
673 void tracing_on(void);
674 void tracing_off(void);
675 int tracing_is_on(void);
676 void tracing_snapshot(void);
677 void tracing_snapshot_alloc(void);
679 extern void tracing_start(void);
680 extern void tracing_stop(void);
682 static inline __printf(1, 2)
683 void ____trace_printk_check_format(const char *fmt, ...)
686 #define __trace_printk_check_format(fmt, args...) \
689 ____trace_printk_check_format(fmt, ##args); \
693 * trace_printk - printf formatting in the ftrace buffer
694 * @fmt: the printf format for printing
696 * Note: __trace_printk is an internal function for trace_printk() and
697 * the @ip is passed in via the trace_printk() macro.
699 * This function allows a kernel developer to debug fast path sections
700 * that printk is not appropriate for. By scattering in various
701 * printk like tracing in the code, a developer can quickly see
702 * where problems are occurring.
704 * This is intended as a debugging tool for the developer only.
705 * Please refrain from leaving trace_printks scattered around in
706 * your code. (Extra memory is used for special buffers that are
707 * allocated when trace_printk() is used.)
709 * A little optimization trick is done here. If there's only one
710 * argument, there's no need to scan the string for printf formats.
711 * The trace_puts() will suffice. But how can we take advantage of
712 * using trace_puts() when trace_printk() has only one argument?
713 * By stringifying the args and checking the size we can tell
714 * whether or not there are args. __stringify((__VA_ARGS__)) will
715 * turn into "()\0" with a size of 3 when there are no args, anything
716 * else will be bigger. All we need to do is define a string to this,
717 * and then take its size and compare to 3. If it's bigger, use
718 * do_trace_printk() otherwise, optimize it to trace_puts(). Then just
719 * let gcc optimize the rest.
722 #define trace_printk(fmt, ...) \
724 char _______STR[] = __stringify((__VA_ARGS__)); \
725 if (sizeof(_______STR) > 3) \
726 do_trace_printk(fmt, ##__VA_ARGS__); \
731 #define do_trace_printk(fmt, args...) \
733 static const char *trace_printk_fmt __used \
734 __attribute__((section("__trace_printk_fmt"))) = \
735 __builtin_constant_p(fmt) ? fmt : NULL; \
737 __trace_printk_check_format(fmt, ##args); \
739 if (__builtin_constant_p(fmt)) \
740 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \
742 __trace_printk(_THIS_IP_, fmt, ##args); \
745 extern __printf(2, 3)
746 int __trace_bprintk(unsigned long ip, const char *fmt, ...);
748 extern __printf(2, 3)
749 int __trace_printk(unsigned long ip, const char *fmt, ...);
752 * trace_puts - write a string into the ftrace buffer
753 * @str: the string to record
755 * Note: __trace_bputs is an internal function for trace_puts and
756 * the @ip is passed in via the trace_puts macro.
758 * This is similar to trace_printk() but is made for those really fast
759 * paths that a developer wants the least amount of "Heisenbug" effects,
760 * where the processing of the print format is still too much.
762 * This function allows a kernel developer to debug fast path sections
763 * that printk is not appropriate for. By scattering in various
764 * printk like tracing in the code, a developer can quickly see
765 * where problems are occurring.
767 * This is intended as a debugging tool for the developer only.
768 * Please refrain from leaving trace_puts scattered around in
769 * your code. (Extra memory is used for special buffers that are
770 * allocated when trace_puts() is used.)
772 * Returns: 0 if nothing was written, positive # if string was.
773 * (1 when __trace_bputs is used, strlen(str) when __trace_puts is used)
776 #define trace_puts(str) ({ \
777 static const char *trace_printk_fmt __used \
778 __attribute__((section("__trace_printk_fmt"))) = \
779 __builtin_constant_p(str) ? str : NULL; \
781 if (__builtin_constant_p(str)) \
782 __trace_bputs(_THIS_IP_, trace_printk_fmt); \
784 __trace_puts(_THIS_IP_, str, strlen(str)); \
786 extern int __trace_bputs(unsigned long ip, const char *str);
787 extern int __trace_puts(unsigned long ip, const char *str, int size);
789 extern void trace_dump_stack(int skip);
792 * The double __builtin_constant_p is because gcc will give us an error
793 * if we try to allocate the static variable to fmt if it is not a
794 * constant. Even with the outer if statement.
796 #define ftrace_vprintk(fmt, vargs) \
798 if (__builtin_constant_p(fmt)) { \
799 static const char *trace_printk_fmt __used \
800 __attribute__((section("__trace_printk_fmt"))) = \
801 __builtin_constant_p(fmt) ? fmt : NULL; \
803 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs); \
805 __ftrace_vprintk(_THIS_IP_, fmt, vargs); \
808 extern __printf(2, 0) int
809 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
811 extern __printf(2, 0) int
812 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
814 extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
816 static inline void tracing_start(void) { }
817 static inline void tracing_stop(void) { }
818 static inline void trace_dump_stack(int skip) { }
820 static inline void tracing_on(void) { }
821 static inline void tracing_off(void) { }
822 static inline int tracing_is_on(void) { return 0; }
823 static inline void tracing_snapshot(void) { }
824 static inline void tracing_snapshot_alloc(void) { }
826 static inline __printf(1, 2)
827 int trace_printk(const char *fmt, ...)
831 static __printf(1, 0) inline int
832 ftrace_vprintk(const char *fmt, va_list ap)
836 static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
837 #endif /* CONFIG_TRACING */
840 * min()/max()/clamp() macros must accomplish three things:
842 * - avoid multiple evaluations of the arguments (so side-effects like
843 * "x++" happen only once) when non-constant.
844 * - perform strict type-checking (to generate warnings instead of
845 * nasty runtime surprises). See the "unnecessary" pointer comparison
847 * - retain result as a constant expressions when called with only
848 * constant expressions (to avoid tripping VLA warnings in stack
851 #define __typecheck(x, y) \
852 (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
855 * This returns a constant expression while determining if an argument is
856 * a constant expression, most importantly without evaluating the argument.
857 * Glory to Martin Uecker <Martin.Uecker@med.uni-goettingen.de>
859 #define __is_constexpr(x) \
860 (sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8)))
862 #define __no_side_effects(x, y) \
863 (__is_constexpr(x) && __is_constexpr(y))
865 #define __safe_cmp(x, y) \
866 (__typecheck(x, y) && __no_side_effects(x, y))
868 #define __cmp(x, y, op) ((x) op (y) ? (x) : (y))
870 #define __cmp_once(x, y, unique_x, unique_y, op) ({ \
871 typeof(x) unique_x = (x); \
872 typeof(y) unique_y = (y); \
873 __cmp(unique_x, unique_y, op); })
875 #define __careful_cmp(x, y, op) \
876 __builtin_choose_expr(__safe_cmp(x, y), \
878 __cmp_once(x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y), op))
881 * min - return minimum of two values of the same or compatible types
885 #define min(x, y) __careful_cmp(x, y, <)
888 * max - return maximum of two values of the same or compatible types
892 #define max(x, y) __careful_cmp(x, y, >)
895 * min3 - return minimum of three values
900 #define min3(x, y, z) min((typeof(x))min(x, y), z)
903 * max3 - return maximum of three values
908 #define max3(x, y, z) max((typeof(x))max(x, y), z)
911 * min_not_zero - return the minimum that is _not_ zero, unless both are zero
915 #define min_not_zero(x, y) ({ \
916 typeof(x) __x = (x); \
917 typeof(y) __y = (y); \
918 __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
921 * clamp - return a value clamped to a given range with strict typechecking
922 * @val: current value
923 * @lo: lowest allowable value
924 * @hi: highest allowable value
926 * This macro does strict typechecking of @lo/@hi to make sure they are of the
927 * same type as @val. See the unnecessary pointer comparisons.
929 #define clamp(val, lo, hi) min((typeof(val))max(val, lo), hi)
932 * ..and if you can't take the strict
933 * types, you can specify one yourself.
935 * Or not use min/max/clamp at all, of course.
939 * min_t - return minimum of two values, using the specified type
940 * @type: data type to use
944 #define min_t(type, x, y) __careful_cmp((type)(x), (type)(y), <)
947 * max_t - return maximum of two values, using the specified type
948 * @type: data type to use
952 #define max_t(type, x, y) __careful_cmp((type)(x), (type)(y), >)
955 * clamp_t - return a value clamped to a given range using a given type
956 * @type: the type of variable to use
957 * @val: current value
958 * @lo: minimum allowable value
959 * @hi: maximum allowable value
961 * This macro does no typechecking and uses temporary variables of type
962 * @type to make all the comparisons.
964 #define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi)
967 * clamp_val - return a value clamped to a given range using val's type
968 * @val: current value
969 * @lo: minimum allowable value
970 * @hi: maximum allowable value
972 * This macro does no typechecking and uses temporary variables of whatever
973 * type the input argument @val is. This is useful when @val is an unsigned
974 * type and @lo and @hi are literals that will otherwise be assigned a signed
977 #define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)
981 * swap - swap values of @a and @b
986 do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
988 /* This counts to 12. Any more, it will return 13th argument. */
989 #define __COUNT_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _n, X...) _n
990 #define COUNT_ARGS(X...) __COUNT_ARGS(, ##X, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
992 #define __CONCAT(a, b) a ## b
993 #define CONCATENATE(a, b) __CONCAT(a, b)
996 * container_of - cast a member of a structure out to the containing structure
997 * @ptr: the pointer to the member.
998 * @type: the type of the container struct this is embedded in.
999 * @member: the name of the member within the struct.
1002 #define container_of(ptr, type, member) ({ \
1003 void *__mptr = (void *)(ptr); \
1004 BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
1005 !__same_type(*(ptr), void), \
1006 "pointer type mismatch in container_of()"); \
1007 ((type *)(__mptr - offsetof(type, member))); })
1010 * container_of_safe - cast a member of a structure out to the containing structure
1011 * @ptr: the pointer to the member.
1012 * @type: the type of the container struct this is embedded in.
1013 * @member: the name of the member within the struct.
1015 * If IS_ERR_OR_NULL(ptr), ptr is returned unchanged.
1017 #define container_of_safe(ptr, type, member) ({ \
1018 void *__mptr = (void *)(ptr); \
1019 BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
1020 !__same_type(*(ptr), void), \
1021 "pointer type mismatch in container_of()"); \
1022 IS_ERR_OR_NULL(__mptr) ? ERR_CAST(__mptr) : \
1023 ((type *)(__mptr - offsetof(type, member))); })
1025 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
1026 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
1027 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
1030 /* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */
1031 #define VERIFY_OCTAL_PERMISSIONS(perms) \
1032 (BUILD_BUG_ON_ZERO((perms) < 0) + \
1033 BUILD_BUG_ON_ZERO((perms) > 0777) + \
1034 /* USER_READABLE >= GROUP_READABLE >= OTHER_READABLE */ \
1035 BUILD_BUG_ON_ZERO((((perms) >> 6) & 4) < (((perms) >> 3) & 4)) + \
1036 BUILD_BUG_ON_ZERO((((perms) >> 3) & 4) < ((perms) & 4)) + \
1037 /* USER_WRITABLE >= GROUP_WRITABLE */ \
1038 BUILD_BUG_ON_ZERO((((perms) >> 6) & 2) < (((perms) >> 3) & 2)) + \
1039 /* OTHER_WRITABLE? Generally considered a bad idea. */ \
1040 BUILD_BUG_ON_ZERO((perms) & 2) + \