1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_KERNEL_H
3#define _LINUX_KERNEL_H
4
5
6#include <stdarg.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
21#define STACK_MAGIC 0xdeadbeef
22
23/**
24 * REPEAT_BYTE - repeat the value @x multiple times as an unsigned long value
25 * @x: value to repeat
26 *
27 * NOTE: @x is not checked for > 0xff; larger values produce odd results.
28 */
29#define REPEAT_BYTE(x) ((~0ul / 0xff) * (x))
30
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)
37
38/* generic data direction definitions */
39#define READ 0
40#define WRITE 1
41
42/**
43 * ARRAY_SIZE - get the number of elements in array @arr
44 * @arr: array to be sized
45 */
46#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
47
48#define u64_to_user_ptr(x) ( \
49{ \
50 typecheck(u64, x); \
51 (void __user *)(uintptr_t)x; \
52} \
53)
54
55/*
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.
60 */
61#define __round_mask(x, y) ((__typeof__(x))((y)-1))
62/**
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)
66 *
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.
69 */
70#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
71/**
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)
75 *
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.
78 */
79#define round_down(x, y) ((x) & ~__round_mask(x, y))
80
81/**
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.
87 */
88#define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
89
90#define DIV_ROUND_UP __KERNEL_DIV_ROUND_UP
91
92#define DIV_ROUND_DOWN_ULL(ll, d) \
93 ({ unsigned long long _tmp = (ll); do_div(_tmp, d); _tmp; })
94
95#define DIV_ROUND_UP_ULL(ll, d) DIV_ROUND_DOWN_ULL((ll) + (d) - 1, (d))
96
97#if BITS_PER_LONG == 32
98# define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d)
99#else
100# define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d)
101#endif
102
103/**
104 * roundup - round up to the next specified multiple
105 * @x: the value to up
106 * @y: multiple to round up to
107 *
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().
110 */
111#define roundup(x, y) ( \
112{ \
113 typeof(y) __y = y; \
114 (((x) + (__y - 1)) / __y) * __y; \
115} \
116)
117/**
118 * rounddown - round down to next specified multiple
119 * @x: the value to round
120 * @y: multiple to round down to
121 *
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().
124 */
125#define rounddown(x, y) ( \
126{ \
127 typeof(x) __x = (x); \
128 __x - (__x % (y)); \
129} \
130)
131
132/*
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.
137 */
138#define DIV_ROUND_CLOSEST(x, divisor)( \
139{ \
140 typeof(x) __x = x; \
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)); \
147} \
148)
149/*
150 * Same as above but for u64 dividends. divisor must be a 32-bit
151 * number.
152 */
153#define DIV_ROUND_CLOSEST_ULL(x, divisor)( \
154{ \
155 typeof(divisor) __d = divisor; \
156 unsigned long long _tmp = (x) + (__d) / 2; \
157 do_div(_tmp, __d); \
158 _tmp; \
159} \
160)
161
162/*
163 * Multiplies an integer by a fraction, while avoiding unnecessary
164 * overflow or loss of precision.
165 */
166#define mult_frac(x, numer, denom)( \
167{ \
168 typeof(x) quot = (x) / (denom); \
169 typeof(x) rem = (x) % (denom); \
170 (quot * (numer)) + ((rem * (numer)) / (denom)); \
171} \
172)
173
174
175#define _RET_IP_ (unsigned long)__builtin_return_address(0)
176#define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; })
177
178#ifdef CONFIG_LBDAF
179# define sector_div(a, b) do_div(a, b)
180#else
181# define sector_div(n, b)( \
182{ \
183 int _res; \
184 _res = (n) % (b); \
185 (n) /= (b); \
186 _res; \
187} \
188)
189#endif
190
191/**
192 * upper_32_bits - return bits 32-63 of a number
193 * @n: the number we're accessing
194 *
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
197 * 32-bits.
198 */
199#define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
200
201/**
202 * lower_32_bits - return bits 0-31 of a number
203 * @n: the number we're accessing
204 */
205#define lower_32_bits(n) ((u32)(n))
206
207struct completion;
208struct pt_regs;
209struct user;
210
211#ifdef CONFIG_PREEMPT_VOLUNTARY
212extern int _cond_resched(void);
213# define might_resched() _cond_resched()
214#else
215# define might_resched() do { } while (0)
216#endif
217
218#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
219extern void ___might_sleep(const char *file, int line, int preempt_offset);
220extern void __might_sleep(const char *file, int line, int preempt_offset);
221extern void __cant_sleep(const char *file, int line, int preempt_offset);
222
223/**
224 * might_sleep - annotation for functions that can sleep
225 *
226 * this macro will print a stack trace if it is executed in an atomic
227 * context (spinlock, irq-handler, ...).
228 *
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
231 * supposed to.
232 */
233# define might_sleep() \
234 do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
235/**
236 * cant_sleep - annotation for functions that cannot sleep
237 *
238 * this macro will print a stack trace if it is executed with preemption enabled
239 */
240# define cant_sleep() \
241 do { __cant_sleep(__FILE__, __LINE__, 0); } while (0)
242# define sched_annotate_sleep() (current->task_state_change = 0)
243#else
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)
251#endif
252
253#define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
254
255/**
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.
260 *
261 * Return: an absolute value of x.
262 */
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; }), \
271 ((void)0)))))))
272
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)
277
278/**
279 * reciprocal_scale - "scale" a value into range [0, ep_ro)
280 * @val: value
281 * @ep_ro: right open interval endpoint
282 *
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.
289 *
290 * Return: a result based on @val in interval [0, @ep_ro).
291 */
292static inline u32 reciprocal_scale(u32 val, u32 ep_ro)
293{
294 return (u32)(((u64) val * ep_ro) >> 32);
295}
296
297#if defined(CONFIG_MMU) && \
298 (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP))
299#define might_fault() __might_fault(__FILE__, __LINE__)
300void __might_fault(const char *file, int line);
301#else
302static inline void might_fault(void) { }
303#endif
304
305extern struct atomic_notifier_head panic_notifier_list;
306extern long (*panic_blink)(int state);
307__printf(1, 2)
308void panic(const char *fmt, ...) __noreturn __cold;
309void nmi_panic(struct pt_regs *regs, const char *msg);
310extern void oops_enter(void);
311extern void oops_exit(void);
312void print_oops_end_marker(void);
313extern int oops_may_print(void);
314void do_exit(long error_code) __noreturn;
315void complete_and_exit(struct completion *, long) __noreturn;
316
317#ifdef CONFIG_ARCH_HAS_REFCOUNT
318void refcount_error_report(struct pt_regs *regs, const char *err);
319#else
320static inline void refcount_error_report(struct pt_regs *regs, const char *err)
321{ }
322#endif
323
324/* Internal, do not use. */
325int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
326int __must_check _kstrtol(const char *s, unsigned int base, long *res);
327
328int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
329int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
330
331/**
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.
342 *
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
345 * be checked.
346*/
347static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
348{
349 /*
350 * We want to shortcut function call, but
351 * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
352 */
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);
356 else
357 return _kstrtoul(s, base, res);
358}
359
360/**
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.
371 *
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
374 * be checked.
375 */
376static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
377{
378 /*
379 * We want to shortcut function call, but
380 * __builtin_types_compatible_p(long, long long) = 0.
381 */
382 if (sizeof(long) == sizeof(long long) &&
383 __alignof__(long) == __alignof__(long long))
384 return kstrtoll(s, base, (long long *)res);
385 else
386 return _kstrtol(s, base, res);
387}
388
389int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
390int __must_check kstrtoint(const char *s, unsigned int base, int *res);
391
392static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
393{
394 return kstrtoull(s, base, res);
395}
396
397static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
398{
399 return kstrtoll(s, base, res);
400}
401
402static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
403{
404 return kstrtouint(s, base, res);
405}
406
407static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
408{
409 return kstrtoint(s, base, res);
410}
411
412int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
413int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
414int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
415int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
416int __must_check kstrtobool(const char *s, bool *res);
417
418int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
419int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
420int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
421int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
422int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
423int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
424int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
425int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
426int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
427int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
428int __must_check kstrtobool_from_user(const char __user *s, size_t count, bool *res);
429
430static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
431{
432 return kstrtoull_from_user(s, count, base, res);
433}
434
435static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
436{
437 return kstrtoll_from_user(s, count, base, res);
438}
439
440static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
441{
442 return kstrtouint_from_user(s, count, base, res);
443}
444
445static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
446{
447 return kstrtoint_from_user(s, count, base, res);
448}
449
450/* Obsolete, do not use. Use kstrto<foo> instead */
451
452extern unsigned long simple_strtoul(const char *,char **,unsigned int);
453extern long simple_strtol(const char *,char **,unsigned int);
454extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
455extern long long simple_strtoll(const char *,char **,unsigned int);
456
457extern int num_to_str(char *buf, int size,
458 unsigned long long num, unsigned int width);
459
460/* lib/printf utilities */
461
462extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
463extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
464extern __printf(3, 4)
465int snprintf(char *buf, size_t size, const char *fmt, ...);
466extern __printf(3, 0)
467int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
468extern __printf(3, 4)
469int scnprintf(char *buf, size_t size, const char *fmt, ...);
470extern __printf(3, 0)
471int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
472extern __printf(2, 3) __malloc
473char *kasprintf(gfp_t gfp, const char *fmt, ...);
474extern __printf(2, 0) __malloc
475char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
476extern __printf(2, 0)
477const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list args);
478
479extern __scanf(2, 3)
480int sscanf(const char *, const char *, ...);
481extern __scanf(2, 0)
482int vsscanf(const char *, const char *, va_list);
483
484extern int get_option(char **str, int *pint);
485extern char *get_options(const char *str, int nints, int *ints);
486extern unsigned long long memparse(const char *ptr, char **retptr);
487extern bool parse_option_str(const char *str, const char *option);
488extern char *next_arg(char *args, char **param, char **val);
489
490extern int core_kernel_text(unsigned long addr);
491extern int init_kernel_text(unsigned long addr);
492extern int core_kernel_data(unsigned long addr);
493extern int __kernel_text_address(unsigned long addr);
494extern int kernel_text_address(unsigned long addr);
495extern int func_ptr_is_kernel_text(void *ptr);
496
497unsigned long int_sqrt(unsigned long);
498
499#if BITS_PER_LONG < 64
500u32 int_sqrt64(u64 x);
501#else
502static inline u32 int_sqrt64(u64 x)
503{
504 return (u32)int_sqrt(x);
505}
506#endif
507
508extern void bust_spinlocks(int yes);
509extern int oops_in_progress; /* If set, an oops, panic(), BUG() or die() is in progress */
510extern int panic_timeout;
511extern unsigned long panic_print;
512extern int panic_on_oops;
513extern int panic_on_unrecovered_nmi;
514extern int panic_on_io_nmi;
515extern int panic_on_warn;
516extern int sysctl_panic_on_rcu_stall;
517extern int sysctl_panic_on_stackoverflow;
518
519extern bool crash_kexec_post_notifiers;
520
521/*
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().
525 */
526extern atomic_t panic_cpu;
527#define PANIC_CPU_INVALID -1
528
529/*
530 * Only to be used by arch init code. If the user over-wrote the default
531 * CONFIG_PANIC_TIMEOUT, honor it.
532 */
533static inline void set_arch_panic_timeout(int timeout, int arch_default_timeout)
534{
535 if (panic_timeout == arch_default_timeout)
536 panic_timeout = timeout;
537}
538extern const char *print_tainted(void);
539enum lockdep_ok {
540 LOCKDEP_STILL_OK,
541 LOCKDEP_NOW_UNRELIABLE
542};
543extern void add_taint(unsigned flag, enum lockdep_ok);
544extern int test_taint(unsigned flag);
545extern unsigned long get_taint(void);
546extern int root_mountflags;
547
548extern bool early_boot_irqs_disabled;
549
550/*
551 * Values used for system_state. Ordering of the states must not be changed
552 * as code checks for <, <=, >, >= STATE.
553 */
554extern enum system_states {
555 SYSTEM_BOOTING,
556 SYSTEM_SCHEDULING,
557 SYSTEM_RUNNING,
558 SYSTEM_HALT,
559 SYSTEM_POWER_OFF,
560 SYSTEM_RESTART,
561 SYSTEM_SUSPEND,
562} system_state;
563
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
571#define TAINT_USER 6
572#define TAINT_DIE 7
573#define TAINT_OVERRIDDEN_ACPI_TABLE 8
574#define TAINT_WARN 9
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
581#define TAINT_AUX 16
582#define TAINT_RANDSTRUCT 17
583#define TAINT_FLAGS_COUNT 18
584
585struct taint_flag {
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 */
589};
590
591extern const struct taint_flag taint_flags[TAINT_FLAGS_COUNT];
592
593extern 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]
596
597static inline char *hex_byte_pack(char *buf, u8 byte)
598{
599 *buf++ = hex_asc_hi(byte);
600 *buf++ = hex_asc_lo(byte);
601 return buf;
602}
603
604extern 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]
607
608static inline char *hex_byte_pack_upper(char *buf, u8 byte)
609{
610 *buf++ = hex_asc_upper_hi(byte);
611 *buf++ = hex_asc_upper_lo(byte);
612 return buf;
613}
614
615extern int hex_to_bin(char ch);
616extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
617extern char *bin2hex(char *dst, const void *src, size_t count);
618
619bool mac_pton(const char *s, u8 *mac);
620
621/*
622 * General tracing related utility functions - trace_printk(),
623 * tracing_on/tracing_off and tracing_start()/tracing_stop
624 *
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.
632 *
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.
637 *
638 * Most likely, you want to use tracing_on/tracing_off.
639 */
640
641enum ftrace_dump_mode {
642 DUMP_NONE,
643 DUMP_ALL,
644 DUMP_ORIG,
645};
646
647#ifdef CONFIG_TRACING
648void tracing_on(void);
649void tracing_off(void);
650int tracing_is_on(void);
651void tracing_snapshot(void);
652void tracing_snapshot_alloc(void);
653
654extern void tracing_start(void);
655extern void tracing_stop(void);
656
657static inline __printf(1, 2)
658void ____trace_printk_check_format(const char *fmt, ...)
659{
660}
661#define __trace_printk_check_format(fmt, args...) \
662do { \
663 if (0) \
664 ____trace_printk_check_format(fmt, ##args); \
665} while (0)
666
667/**
668 * trace_printk - printf formatting in the ftrace buffer
669 * @fmt: the printf format for printing
670 *
671 * Note: __trace_printk is an internal function for trace_printk() and
672 * the @ip is passed in via the trace_printk() macro.
673 *
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.
678 *
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.)
683 *
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.
695 */
696
697#define trace_printk(fmt, ...) \
698do { \
699 char _______STR[] = __stringify((__VA_ARGS__)); \
700 if (sizeof(_______STR) > 3) \
701 do_trace_printk(fmt, ##__VA_ARGS__); \
702 else \
703 trace_puts(fmt); \
704} while (0)
705
706#define do_trace_printk(fmt, args...) \
707do { \
708 static const char *trace_printk_fmt __used \
709 __attribute__((section("__trace_printk_fmt"))) = \
710 __builtin_constant_p(fmt) ? fmt : NULL; \
711 \
712 __trace_printk_check_format(fmt, ##args); \
713 \
714 if (__builtin_constant_p(fmt)) \
715 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \
716 else \
717 __trace_printk(_THIS_IP_, fmt, ##args); \
718} while (0)
719
720extern __printf(2, 3)
721int __trace_bprintk(unsigned long ip, const char *fmt, ...);
722
723extern __printf(2, 3)
724int __trace_printk(unsigned long ip, const char *fmt, ...);
725
726/**
727 * trace_puts - write a string into the ftrace buffer
728 * @str: the string to record
729 *
730 * Note: __trace_bputs is an internal function for trace_puts and
731 * the @ip is passed in via the trace_puts macro.
732 *
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.
736 *
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.
741 *
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.)
746 *
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)
749 */
750
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; \
755 \
756 if (__builtin_constant_p(str)) \
757 __trace_bputs(_THIS_IP_, trace_printk_fmt); \
758 else \
759 __trace_puts(_THIS_IP_, str, strlen(str)); \
760})
761extern int __trace_bputs(unsigned long ip, const char *str);
762extern int __trace_puts(unsigned long ip, const char *str, int size);
763
764extern void trace_dump_stack(int skip);
765
766/*
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.
770 */
771#define ftrace_vprintk(fmt, vargs) \
772do { \
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; \
777 \
778 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs); \
779 } else \
780 __ftrace_vprintk(_THIS_IP_, fmt, vargs); \
781} while (0)
782
783extern __printf(2, 0) int
784__ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
785
786extern __printf(2, 0) int
787__ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
788
789extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
790#else
791static inline void tracing_start(void) { }
792static inline void tracing_stop(void) { }
793static inline void trace_dump_stack(int skip) { }
794
795static inline void tracing_on(void) { }
796static inline void tracing_off(void) { }
797static inline int tracing_is_on(void) { return 0; }
798static inline void tracing_snapshot(void) { }
799static inline void tracing_snapshot_alloc(void) { }
800
801static inline __printf(1, 2)
802int trace_printk(const char *fmt, ...)
803{
804 return 0;
805}
806static __printf(1, 0) inline int
807ftrace_vprintk(const char *fmt, va_list ap)
808{
809 return 0;
810}
811static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
812#endif /* CONFIG_TRACING */
813
814/*
815 * min()/max()/clamp() macros must accomplish three things:
816 *
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
821 * in __typecheck().
822 * - retain result as a constant expressions when called with only
823 * constant expressions (to avoid tripping VLA warnings in stack
824 * allocation usage).
825 */
826#define __typecheck(x, y) \
827 (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
828
829/*
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>
833 */
834#define __is_constexpr(x) \
835 (sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8)))
836
837#define __no_side_effects(x, y) \
838 (__is_constexpr(x) && __is_constexpr(y))
839
840#define __safe_cmp(x, y) \
841 (__typecheck(x, y) && __no_side_effects(x, y))
842
843#define __cmp(x, y, op) ((x) op (y) ? (x) : (y))
844
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); })
849
850#define __careful_cmp(x, y, op) \
851 __builtin_choose_expr(__safe_cmp(x, y), \
852 __cmp(x, y, op), \
853 __cmp_once(x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y), op))
854
855/**
856 * min - return minimum of two values of the same or compatible types
857 * @x: first value
858 * @y: second value
859 */
860#define min(x, y) __careful_cmp(x, y, <)
861
862/**
863 * max - return maximum of two values of the same or compatible types
864 * @x: first value
865 * @y: second value
866 */
867#define max(x, y) __careful_cmp(x, y, >)
868
869/**
870 * min3 - return minimum of three values
871 * @x: first value
872 * @y: second value
873 * @z: third value
874 */
875#define min3(x, y, z) min((typeof(x))min(x, y), z)
876
877/**
878 * max3 - return maximum of three values
879 * @x: first value
880 * @y: second value
881 * @z: third value
882 */
883#define max3(x, y, z) max((typeof(x))max(x, y), z)
884
885/**
886 * min_not_zero - return the minimum that is _not_ zero, unless both are zero
887 * @x: value1
888 * @y: value2
889 */
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)); })
894
895/**
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
900 *
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.
903 */
904#define clamp(val, lo, hi) min((typeof(val))max(val, lo), hi)
905
906/*
907 * ..and if you can't take the strict
908 * types, you can specify one yourself.
909 *
910 * Or not use min/max/clamp at all, of course.
911 */
912
913/**
914 * min_t - return minimum of two values, using the specified type
915 * @type: data type to use
916 * @x: first value
917 * @y: second value
918 */
919#define min_t(type, x, y) __careful_cmp((type)(x), (type)(y), <)
920
921/**
922 * max_t - return maximum of two values, using the specified type
923 * @type: data type to use
924 * @x: first value
925 * @y: second value
926 */
927#define max_t(type, x, y) __careful_cmp((type)(x), (type)(y), >)
928
929/**
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
935 *
936 * This macro does no typechecking and uses temporary variables of type
937 * @type to make all the comparisons.
938 */
939#define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi)
940
941/**
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
946 *
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
950 * integer type.
951 */
952#define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)
953
954
955/**
956 * swap - swap values of @a and @b
957 * @a: first value
958 * @b: second value
959 */
960#define swap(a, b) \
961 do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
962
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)
966
967#define __CONCAT(a, b) a ## b
968#define CONCATENATE(a, b) __CONCAT(a, b)
969
970/**
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.
975 *
976 */
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))); })
983
984/**
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.
989 *
990 * If IS_ERR_OR_NULL(ptr), ptr is returned unchanged.
991 */
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))); })
999
1000/* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
1001#ifdef CONFIG_FTRACE_MCOUNT_RECORD
1002# define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
1003#endif
1004
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) + \
1016 (perms))
1017#endif
1018