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 IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0)
38 /* generic data direction definitions */
43 * ARRAY_SIZE - get the number of elements in array @arr
44 * @arr: array to be sized
46 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
48 #define u64_to_user_ptr(x) ( \
50 typecheck(u64, (x)); \
51 (void __user *)(uintptr_t)(x); \
56 * This looks more complex than it should be. But we need to
57 * get the type for the ~ right in round_down (it needs to be
58 * as wide as the result!), and we want to evaluate the macro
59 * arguments just once each.
61 #define __round_mask(x, y) ((__typeof__(x))((y)-1))
63 * round_up - round up to next specified power of 2
64 * @x: the value to round
65 * @y: multiple to round up to (must be a power of 2)
67 * Rounds @x up to next multiple of @y (which must be a power of 2).
68 * To perform arbitrary rounding up, use roundup() below.
70 #define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
72 * round_down - round down to next specified power of 2
73 * @x: the value to round
74 * @y: multiple to round down to (must be a power of 2)
76 * Rounds @x down to next multiple of @y (which must be a power of 2).
77 * To perform arbitrary rounding down, use rounddown() below.
79 #define round_down(x, y) ((x) & ~__round_mask(x, y))
82 * FIELD_SIZEOF - get the size of a struct's field
83 * @t: the target struct
84 * @f: the target struct's field
85 * Return: the size of @f in the struct definition without having a
86 * declared instance of @t.
88 #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
90 #define DIV_ROUND_UP __KERNEL_DIV_ROUND_UP
92 #define DIV_ROUND_DOWN_ULL(ll, d) \
93 ({ unsigned long long _tmp = (ll); do_div(_tmp, d); _tmp; })
95 #define DIV_ROUND_UP_ULL(ll, d) DIV_ROUND_DOWN_ULL((ll) + (d) - 1, (d))
97 #if BITS_PER_LONG == 32
98 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d)
100 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d)
104 * roundup - round up to the next specified multiple
105 * @x: the value to up
106 * @y: multiple to round up to
108 * Rounds @x up to next multiple of @y. If @y will always be a power
109 * of 2, consider using the faster round_up().
111 #define roundup(x, y) ( \
114 (((x) + (__y - 1)) / __y) * __y; \
118 * rounddown - round down to next specified multiple
119 * @x: the value to round
120 * @y: multiple to round down to
122 * Rounds @x down to next multiple of @y. If @y will always be a power
123 * of 2, consider using the faster round_down().
125 #define rounddown(x, y) ( \
127 typeof(x) __x = (x); \
133 * Divide positive or negative dividend by positive or negative divisor
134 * and round to closest integer. Result is undefined for negative
135 * divisors if the dividend variable type is unsigned and for negative
136 * dividends if the divisor variable type is unsigned.
138 #define DIV_ROUND_CLOSEST(x, divisor)( \
141 typeof(divisor) __d = divisor; \
142 (((typeof(x))-1) > 0 || \
143 ((typeof(divisor))-1) > 0 || \
144 (((__x) > 0) == ((__d) > 0))) ? \
145 (((__x) + ((__d) / 2)) / (__d)) : \
146 (((__x) - ((__d) / 2)) / (__d)); \
150 * Same as above but for u64 dividends. divisor must be a 32-bit
153 #define DIV_ROUND_CLOSEST_ULL(x, divisor)( \
155 typeof(divisor) __d = divisor; \
156 unsigned long long _tmp = (x) + (__d) / 2; \
163 * Multiplies an integer by a fraction, while avoiding unnecessary
164 * overflow or loss of precision.
166 #define mult_frac(x, numer, denom)( \
168 typeof(x) quot = (x) / (denom); \
169 typeof(x) rem = (x) % (denom); \
170 (quot * (numer)) + ((rem * (numer)) / (denom)); \
175 #define _RET_IP_ (unsigned long)__builtin_return_address(0)
176 #define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; })
179 # define sector_div(a, b) do_div(a, b)
181 # define sector_div(n, b)( \
192 * upper_32_bits - return bits 32-63 of a number
193 * @n: the number we're accessing
195 * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress
196 * the "right shift count >= width of type" warning when that quantity is
199 #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
202 * lower_32_bits - return bits 0-31 of a number
203 * @n: the number we're accessing
205 #define lower_32_bits(n) ((u32)(n))
211 #ifdef CONFIG_PREEMPT_VOLUNTARY
212 extern int _cond_resched(void);
213 # define might_resched() _cond_resched()
215 # define might_resched() do { } while (0)
218 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
219 extern void ___might_sleep(const char *file, int line, int preempt_offset);
220 extern void __might_sleep(const char *file, int line, int preempt_offset);
221 extern void __cant_sleep(const char *file, int line, int preempt_offset);
224 * might_sleep - annotation for functions that can sleep
226 * this macro will print a stack trace if it is executed in an atomic
227 * context (spinlock, irq-handler, ...).
229 * This is a useful debugging help to be able to catch problems early and not
230 * be bitten later when the calling function happens to sleep when it is not
233 # define might_sleep() \
234 do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
236 * cant_sleep - annotation for functions that cannot sleep
238 * this macro will print a stack trace if it is executed with preemption enabled
240 # define cant_sleep() \
241 do { __cant_sleep(__FILE__, __LINE__, 0); } while (0)
242 # define sched_annotate_sleep() (current->task_state_change = 0)
244 static inline void ___might_sleep(const char *file, int line,
245 int preempt_offset) { }
246 static inline void __might_sleep(const char *file, int line,
247 int preempt_offset) { }
248 # define might_sleep() do { might_resched(); } while (0)
249 # define cant_sleep() do { } while (0)
250 # define sched_annotate_sleep() do { } while (0)
253 #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
256 * abs - return absolute value of an argument
257 * @x: the value. If it is unsigned type, it is converted to signed type first.
258 * char is treated as if it was signed (regardless of whether it really is)
259 * but the macro's return type is preserved as char.
261 * Return: an absolute value of x.
263 #define abs(x) __abs_choose_expr(x, long long, \
264 __abs_choose_expr(x, long, \
265 __abs_choose_expr(x, int, \
266 __abs_choose_expr(x, short, \
267 __abs_choose_expr(x, char, \
268 __builtin_choose_expr( \
269 __builtin_types_compatible_p(typeof(x), char), \
270 (char)({ signed char __x = (x); __x<0?-__x:__x; }), \
273 #define __abs_choose_expr(x, type, other) __builtin_choose_expr( \
274 __builtin_types_compatible_p(typeof(x), signed type) || \
275 __builtin_types_compatible_p(typeof(x), unsigned type), \
276 ({ signed type __x = (x); __x < 0 ? -__x : __x; }), other)
279 * reciprocal_scale - "scale" a value into range [0, ep_ro)
281 * @ep_ro: right open interval endpoint
283 * Perform a "reciprocal multiplication" in order to "scale" a value into
284 * range [0, @ep_ro), where the upper interval endpoint is right-open.
285 * This is useful, e.g. for accessing a index of an array containing
286 * @ep_ro elements, for example. Think of it as sort of modulus, only that
287 * the result isn't that of modulo. ;) Note that if initial input is a
288 * small value, then result will return 0.
290 * Return: a result based on @val in interval [0, @ep_ro).
292 static inline u32 reciprocal_scale(u32 val, u32 ep_ro)
294 return (u32)(((u64) val * ep_ro) >> 32);
297 #if defined(CONFIG_MMU) && \
298 (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP))
299 #define might_fault() __might_fault(__FILE__, __LINE__)
300 void __might_fault(const char *file, int line);
302 static inline void might_fault(void) { }
305 extern struct atomic_notifier_head panic_notifier_list;
306 extern long (*panic_blink)(int state);
308 void panic(const char *fmt, ...) __noreturn __cold;
309 void nmi_panic(struct pt_regs *regs, const char *msg);
310 extern void oops_enter(void);
311 extern void oops_exit(void);
312 void print_oops_end_marker(void);
313 extern int oops_may_print(void);
314 void do_exit(long error_code) __noreturn;
315 void complete_and_exit(struct completion *, long) __noreturn;
317 #ifdef CONFIG_ARCH_HAS_REFCOUNT
318 void refcount_error_report(struct pt_regs *regs, const char *err);
320 static inline void refcount_error_report(struct pt_regs *regs, const char *err)
324 /* Internal, do not use. */
325 int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
326 int __must_check _kstrtol(const char *s, unsigned int base, long *res);
328 int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
329 int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
332 * kstrtoul - convert a string to an unsigned long
333 * @s: The start of the string. The string must be null-terminated, and may also
334 * include a single newline before its terminating null. The first character
335 * may also be a plus sign, but not a minus sign.
336 * @base: The number base to use. The maximum supported base is 16. If base is
337 * given as 0, then the base of the string is automatically detected with the
338 * conventional semantics - If it begins with 0x the number will be parsed as a
339 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
340 * parsed as an octal number. Otherwise it will be parsed as a decimal.
341 * @res: Where to write the result of the conversion on success.
343 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
344 * Used as a replacement for the obsolete simple_strtoull. Return code must
347 static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
350 * We want to shortcut function call, but
351 * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
353 if (sizeof(unsigned long) == sizeof(unsigned long long) &&
354 __alignof__(unsigned long) == __alignof__(unsigned long long))
355 return kstrtoull(s, base, (unsigned long long *)res);
357 return _kstrtoul(s, base, res);
361 * kstrtol - convert a string to a long
362 * @s: The start of the string. The string must be null-terminated, and may also
363 * include a single newline before its terminating null. The first character
364 * may also be a plus sign or a minus sign.
365 * @base: The number base to use. The maximum supported base is 16. If base is
366 * given as 0, then the base of the string is automatically detected with the
367 * conventional semantics - If it begins with 0x the number will be parsed as a
368 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
369 * parsed as an octal number. Otherwise it will be parsed as a decimal.
370 * @res: Where to write the result of the conversion on success.
372 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
373 * Used as a replacement for the obsolete simple_strtoull. Return code must
376 static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
379 * We want to shortcut function call, but
380 * __builtin_types_compatible_p(long, long long) = 0.
382 if (sizeof(long) == sizeof(long long) &&
383 __alignof__(long) == __alignof__(long long))
384 return kstrtoll(s, base, (long long *)res);
386 return _kstrtol(s, base, res);
389 int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
390 int __must_check kstrtoint(const char *s, unsigned int base, int *res);
392 static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
394 return kstrtoull(s, base, res);
397 static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
399 return kstrtoll(s, base, res);
402 static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
404 return kstrtouint(s, base, res);
407 static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
409 return kstrtoint(s, base, res);
412 int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
413 int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
414 int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
415 int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
416 int __must_check kstrtobool(const char *s, bool *res);
418 int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
419 int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
420 int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
421 int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
422 int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
423 int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
424 int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
425 int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
426 int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
427 int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
428 int __must_check kstrtobool_from_user(const char __user *s, size_t count, bool *res);
430 static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
432 return kstrtoull_from_user(s, count, base, res);
435 static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
437 return kstrtoll_from_user(s, count, base, res);
440 static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
442 return kstrtouint_from_user(s, count, base, res);
445 static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
447 return kstrtoint_from_user(s, count, base, res);
450 /* Obsolete, do not use. Use kstrto<foo> instead */
452 extern unsigned long simple_strtoul(const char *,char **,unsigned int);
453 extern long simple_strtol(const char *,char **,unsigned int);
454 extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
455 extern long long simple_strtoll(const char *,char **,unsigned int);
457 extern int num_to_str(char *buf, int size,
458 unsigned long long num, unsigned int width);
460 /* lib/printf utilities */
462 extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
463 extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
464 extern __printf(3, 4)
465 int snprintf(char *buf, size_t size, const char *fmt, ...);
466 extern __printf(3, 0)
467 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
468 extern __printf(3, 4)
469 int scnprintf(char *buf, size_t size, const char *fmt, ...);
470 extern __printf(3, 0)
471 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
472 extern __printf(2, 3) __malloc
473 char *kasprintf(gfp_t gfp, const char *fmt, ...);
474 extern __printf(2, 0) __malloc
475 char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
476 extern __printf(2, 0)
477 const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list args);
480 int sscanf(const char *, const char *, ...);
482 int vsscanf(const char *, const char *, va_list);
484 extern int get_option(char **str, int *pint);
485 extern char *get_options(const char *str, int nints, int *ints);
486 extern unsigned long long memparse(const char *ptr, char **retptr);
487 extern bool parse_option_str(const char *str, const char *option);
488 extern char *next_arg(char *args, char **param, char **val);
490 extern int core_kernel_text(unsigned long addr);
491 extern int init_kernel_text(unsigned long addr);
492 extern int core_kernel_data(unsigned long addr);
493 extern int __kernel_text_address(unsigned long addr);
494 extern int kernel_text_address(unsigned long addr);
495 extern int func_ptr_is_kernel_text(void *ptr);
497 unsigned long int_sqrt(unsigned long);
499 #if BITS_PER_LONG < 64
500 u32 int_sqrt64(u64 x);
502 static inline u32 int_sqrt64(u64 x)
504 return (u32)int_sqrt(x);
508 extern void bust_spinlocks(int yes);
509 extern int oops_in_progress; /* If set, an oops, panic(), BUG() or die() is in progress */
510 extern int panic_timeout;
511 extern unsigned long panic_print;
512 extern int panic_on_oops;
513 extern int panic_on_unrecovered_nmi;
514 extern int panic_on_io_nmi;
515 extern int panic_on_warn;
516 extern int sysctl_panic_on_rcu_stall;
517 extern int sysctl_panic_on_stackoverflow;
519 extern bool crash_kexec_post_notifiers;
522 * panic_cpu is used for synchronizing panic() and crash_kexec() execution. It
523 * holds a CPU number which is executing panic() currently. A value of
524 * PANIC_CPU_INVALID means no CPU has entered panic() or crash_kexec().
526 extern atomic_t panic_cpu;
527 #define PANIC_CPU_INVALID -1
530 * Only to be used by arch init code. If the user over-wrote the default
531 * CONFIG_PANIC_TIMEOUT, honor it.
533 static inline void set_arch_panic_timeout(int timeout, int arch_default_timeout)
535 if (panic_timeout == arch_default_timeout)
536 panic_timeout = timeout;
538 extern const char *print_tainted(void);
541 LOCKDEP_NOW_UNRELIABLE
543 extern void add_taint(unsigned flag, enum lockdep_ok);
544 extern int test_taint(unsigned flag);
545 extern unsigned long get_taint(void);
546 extern int root_mountflags;
548 extern bool early_boot_irqs_disabled;
551 * Values used for system_state. Ordering of the states must not be changed
552 * as code checks for <, <=, >, >= STATE.
554 extern enum system_states {
564 /* This cannot be an enum because some may be used in assembly source. */
565 #define TAINT_PROPRIETARY_MODULE 0
566 #define TAINT_FORCED_MODULE 1
567 #define TAINT_CPU_OUT_OF_SPEC 2
568 #define TAINT_FORCED_RMMOD 3
569 #define TAINT_MACHINE_CHECK 4
570 #define TAINT_BAD_PAGE 5
573 #define TAINT_OVERRIDDEN_ACPI_TABLE 8
575 #define TAINT_CRAP 10
576 #define TAINT_FIRMWARE_WORKAROUND 11
577 #define TAINT_OOT_MODULE 12
578 #define TAINT_UNSIGNED_MODULE 13
579 #define TAINT_SOFTLOCKUP 14
580 #define TAINT_LIVEPATCH 15
582 #define TAINT_RANDSTRUCT 17
583 #define TAINT_FLAGS_COUNT 18
586 char c_true; /* character printed when tainted */
587 char c_false; /* character printed when not tainted */
588 bool module; /* also show as a per-module taint flag */
591 extern const struct taint_flag taint_flags[TAINT_FLAGS_COUNT];
593 extern const char hex_asc[];
594 #define hex_asc_lo(x) hex_asc[((x) & 0x0f)]
595 #define hex_asc_hi(x) hex_asc[((x) & 0xf0) >> 4]
597 static inline char *hex_byte_pack(char *buf, u8 byte)
599 *buf++ = hex_asc_hi(byte);
600 *buf++ = hex_asc_lo(byte);
604 extern const char hex_asc_upper[];
605 #define hex_asc_upper_lo(x) hex_asc_upper[((x) & 0x0f)]
606 #define hex_asc_upper_hi(x) hex_asc_upper[((x) & 0xf0) >> 4]
608 static inline char *hex_byte_pack_upper(char *buf, u8 byte)
610 *buf++ = hex_asc_upper_hi(byte);
611 *buf++ = hex_asc_upper_lo(byte);
615 extern int hex_to_bin(char ch);
616 extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
617 extern char *bin2hex(char *dst, const void *src, size_t count);
619 bool mac_pton(const char *s, u8 *mac);
622 * General tracing related utility functions - trace_printk(),
623 * tracing_on/tracing_off and tracing_start()/tracing_stop
625 * Use tracing_on/tracing_off when you want to quickly turn on or off
626 * tracing. It simply enables or disables the recording of the trace events.
627 * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
628 * file, which gives a means for the kernel and userspace to interact.
629 * Place a tracing_off() in the kernel where you want tracing to end.
630 * From user space, examine the trace, and then echo 1 > tracing_on
631 * to continue tracing.
633 * tracing_stop/tracing_start has slightly more overhead. It is used
634 * by things like suspend to ram where disabling the recording of the
635 * trace is not enough, but tracing must actually stop because things
636 * like calling smp_processor_id() may crash the system.
638 * Most likely, you want to use tracing_on/tracing_off.
641 enum ftrace_dump_mode {
647 #ifdef CONFIG_TRACING
648 void tracing_on(void);
649 void tracing_off(void);
650 int tracing_is_on(void);
651 void tracing_snapshot(void);
652 void tracing_snapshot_alloc(void);
654 extern void tracing_start(void);
655 extern void tracing_stop(void);
657 static inline __printf(1, 2)
658 void ____trace_printk_check_format(const char *fmt, ...)
661 #define __trace_printk_check_format(fmt, args...) \
664 ____trace_printk_check_format(fmt, ##args); \
668 * trace_printk - printf formatting in the ftrace buffer
669 * @fmt: the printf format for printing
671 * Note: __trace_printk is an internal function for trace_printk() and
672 * the @ip is passed in via the trace_printk() macro.
674 * This function allows a kernel developer to debug fast path sections
675 * that printk is not appropriate for. By scattering in various
676 * printk like tracing in the code, a developer can quickly see
677 * where problems are occurring.
679 * This is intended as a debugging tool for the developer only.
680 * Please refrain from leaving trace_printks scattered around in
681 * your code. (Extra memory is used for special buffers that are
682 * allocated when trace_printk() is used.)
684 * A little optimization trick is done here. If there's only one
685 * argument, there's no need to scan the string for printf formats.
686 * The trace_puts() will suffice. But how can we take advantage of
687 * using trace_puts() when trace_printk() has only one argument?
688 * By stringifying the args and checking the size we can tell
689 * whether or not there are args. __stringify((__VA_ARGS__)) will
690 * turn into "()\0" with a size of 3 when there are no args, anything
691 * else will be bigger. All we need to do is define a string to this,
692 * and then take its size and compare to 3. If it's bigger, use
693 * do_trace_printk() otherwise, optimize it to trace_puts(). Then just
694 * let gcc optimize the rest.
697 #define trace_printk(fmt, ...) \
699 char _______STR[] = __stringify((__VA_ARGS__)); \
700 if (sizeof(_______STR) > 3) \
701 do_trace_printk(fmt, ##__VA_ARGS__); \
706 #define do_trace_printk(fmt, args...) \
708 static const char *trace_printk_fmt __used \
709 __attribute__((section("__trace_printk_fmt"))) = \
710 __builtin_constant_p(fmt) ? fmt : NULL; \
712 __trace_printk_check_format(fmt, ##args); \
714 if (__builtin_constant_p(fmt)) \
715 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \
717 __trace_printk(_THIS_IP_, fmt, ##args); \
720 extern __printf(2, 3)
721 int __trace_bprintk(unsigned long ip, const char *fmt, ...);
723 extern __printf(2, 3)
724 int __trace_printk(unsigned long ip, const char *fmt, ...);
727 * trace_puts - write a string into the ftrace buffer
728 * @str: the string to record
730 * Note: __trace_bputs is an internal function for trace_puts and
731 * the @ip is passed in via the trace_puts macro.
733 * This is similar to trace_printk() but is made for those really fast
734 * paths that a developer wants the least amount of "Heisenbug" effects,
735 * where the processing of the print format is still too much.
737 * This function allows a kernel developer to debug fast path sections
738 * that printk is not appropriate for. By scattering in various
739 * printk like tracing in the code, a developer can quickly see
740 * where problems are occurring.
742 * This is intended as a debugging tool for the developer only.
743 * Please refrain from leaving trace_puts scattered around in
744 * your code. (Extra memory is used for special buffers that are
745 * allocated when trace_puts() is used.)
747 * Returns: 0 if nothing was written, positive # if string was.
748 * (1 when __trace_bputs is used, strlen(str) when __trace_puts is used)
751 #define trace_puts(str) ({ \
752 static const char *trace_printk_fmt __used \
753 __attribute__((section("__trace_printk_fmt"))) = \
754 __builtin_constant_p(str) ? str : NULL; \
756 if (__builtin_constant_p(str)) \
757 __trace_bputs(_THIS_IP_, trace_printk_fmt); \
759 __trace_puts(_THIS_IP_, str, strlen(str)); \
761 extern int __trace_bputs(unsigned long ip, const char *str);
762 extern int __trace_puts(unsigned long ip, const char *str, int size);
764 extern void trace_dump_stack(int skip);
767 * The double __builtin_constant_p is because gcc will give us an error
768 * if we try to allocate the static variable to fmt if it is not a
769 * constant. Even with the outer if statement.
771 #define ftrace_vprintk(fmt, vargs) \
773 if (__builtin_constant_p(fmt)) { \
774 static const char *trace_printk_fmt __used \
775 __attribute__((section("__trace_printk_fmt"))) = \
776 __builtin_constant_p(fmt) ? fmt : NULL; \
778 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs); \
780 __ftrace_vprintk(_THIS_IP_, fmt, vargs); \
783 extern __printf(2, 0) int
784 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
786 extern __printf(2, 0) int
787 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
789 extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
791 static inline void tracing_start(void) { }
792 static inline void tracing_stop(void) { }
793 static inline void trace_dump_stack(int skip) { }
795 static inline void tracing_on(void) { }
796 static inline void tracing_off(void) { }
797 static inline int tracing_is_on(void) { return 0; }
798 static inline void tracing_snapshot(void) { }
799 static inline void tracing_snapshot_alloc(void) { }
801 static inline __printf(1, 2)
802 int trace_printk(const char *fmt, ...)
806 static __printf(1, 0) inline int
807 ftrace_vprintk(const char *fmt, va_list ap)
811 static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
812 #endif /* CONFIG_TRACING */
815 * min()/max()/clamp() macros must accomplish three things:
817 * - avoid multiple evaluations of the arguments (so side-effects like
818 * "x++" happen only once) when non-constant.
819 * - perform strict type-checking (to generate warnings instead of
820 * nasty runtime surprises). See the "unnecessary" pointer comparison
822 * - retain result as a constant expressions when called with only
823 * constant expressions (to avoid tripping VLA warnings in stack
826 #define __typecheck(x, y) \
827 (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
830 * This returns a constant expression while determining if an argument is
831 * a constant expression, most importantly without evaluating the argument.
832 * Glory to Martin Uecker <Martin.Uecker@med.uni-goettingen.de>
834 #define __is_constexpr(x) \
835 (sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8)))
837 #define __no_side_effects(x, y) \
838 (__is_constexpr(x) && __is_constexpr(y))
840 #define __safe_cmp(x, y) \
841 (__typecheck(x, y) && __no_side_effects(x, y))
843 #define __cmp(x, y, op) ((x) op (y) ? (x) : (y))
845 #define __cmp_once(x, y, unique_x, unique_y, op) ({ \
846 typeof(x) unique_x = (x); \
847 typeof(y) unique_y = (y); \
848 __cmp(unique_x, unique_y, op); })
850 #define __careful_cmp(x, y, op) \
851 __builtin_choose_expr(__safe_cmp(x, y), \
853 __cmp_once(x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y), op))
856 * min - return minimum of two values of the same or compatible types
860 #define min(x, y) __careful_cmp(x, y, <)
863 * max - return maximum of two values of the same or compatible types
867 #define max(x, y) __careful_cmp(x, y, >)
870 * min3 - return minimum of three values
875 #define min3(x, y, z) min((typeof(x))min(x, y), z)
878 * max3 - return maximum of three values
883 #define max3(x, y, z) max((typeof(x))max(x, y), z)
886 * min_not_zero - return the minimum that is _not_ zero, unless both are zero
890 #define min_not_zero(x, y) ({ \
891 typeof(x) __x = (x); \
892 typeof(y) __y = (y); \
893 __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
896 * clamp - return a value clamped to a given range with strict typechecking
897 * @val: current value
898 * @lo: lowest allowable value
899 * @hi: highest allowable value
901 * This macro does strict typechecking of @lo/@hi to make sure they are of the
902 * same type as @val. See the unnecessary pointer comparisons.
904 #define clamp(val, lo, hi) min((typeof(val))max(val, lo), hi)
907 * ..and if you can't take the strict
908 * types, you can specify one yourself.
910 * Or not use min/max/clamp at all, of course.
914 * min_t - return minimum of two values, using the specified type
915 * @type: data type to use
919 #define min_t(type, x, y) __careful_cmp((type)(x), (type)(y), <)
922 * max_t - return maximum of two values, using the specified type
923 * @type: data type to use
927 #define max_t(type, x, y) __careful_cmp((type)(x), (type)(y), >)
930 * clamp_t - return a value clamped to a given range using a given type
931 * @type: the type of variable to use
932 * @val: current value
933 * @lo: minimum allowable value
934 * @hi: maximum allowable value
936 * This macro does no typechecking and uses temporary variables of type
937 * @type to make all the comparisons.
939 #define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi)
942 * clamp_val - return a value clamped to a given range using val's type
943 * @val: current value
944 * @lo: minimum allowable value
945 * @hi: maximum allowable value
947 * This macro does no typechecking and uses temporary variables of whatever
948 * type the input argument @val is. This is useful when @val is an unsigned
949 * type and @lo and @hi are literals that will otherwise be assigned a signed
952 #define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)
956 * swap - swap values of @a and @b
961 do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
963 /* This counts to 12. Any more, it will return 13th argument. */
964 #define __COUNT_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _n, X...) _n
965 #define COUNT_ARGS(X...) __COUNT_ARGS(, ##X, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
967 #define __CONCAT(a, b) a ## b
968 #define CONCATENATE(a, b) __CONCAT(a, b)
971 * container_of - cast a member of a structure out to the containing structure
972 * @ptr: the pointer to the member.
973 * @type: the type of the container struct this is embedded in.
974 * @member: the name of the member within the struct.
977 #define container_of(ptr, type, member) ({ \
978 void *__mptr = (void *)(ptr); \
979 BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
980 !__same_type(*(ptr), void), \
981 "pointer type mismatch in container_of()"); \
982 ((type *)(__mptr - offsetof(type, member))); })
985 * container_of_safe - cast a member of a structure out to the containing structure
986 * @ptr: the pointer to the member.
987 * @type: the type of the container struct this is embedded in.
988 * @member: the name of the member within the struct.
990 * If IS_ERR_OR_NULL(ptr), ptr is returned unchanged.
992 #define container_of_safe(ptr, type, member) ({ \
993 void *__mptr = (void *)(ptr); \
994 BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
995 !__same_type(*(ptr), void), \
996 "pointer type mismatch in container_of()"); \
997 IS_ERR_OR_NULL(__mptr) ? ERR_CAST(__mptr) : \
998 ((type *)(__mptr - offsetof(type, member))); })
1000 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
1001 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
1002 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
1005 /* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */
1006 #define VERIFY_OCTAL_PERMISSIONS(perms) \
1007 (BUILD_BUG_ON_ZERO((perms) < 0) + \
1008 BUILD_BUG_ON_ZERO((perms) > 0777) + \
1009 /* USER_READABLE >= GROUP_READABLE >= OTHER_READABLE */ \
1010 BUILD_BUG_ON_ZERO((((perms) >> 6) & 4) < (((perms) >> 3) & 4)) + \
1011 BUILD_BUG_ON_ZERO((((perms) >> 3) & 4) < ((perms) & 4)) + \
1012 /* USER_WRITABLE >= GROUP_WRITABLE */ \
1013 BUILD_BUG_ON_ZERO((((perms) >> 6) & 2) < (((perms) >> 3) & 2)) + \
1014 /* OTHER_WRITABLE? Generally considered a bad idea. */ \
1015 BUILD_BUG_ON_ZERO((perms) & 2) + \