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/linkage.h>
8#include <linux/stddef.h>
9#include <linux/types.h>
10#include <linux/compiler.h>
11#include <linux/bitops.h>
12#include <linux/log2.h>
13#include <linux/typecheck.h>
14#include <linux/printk.h>
15#include <linux/build_bug.h>
16#include <asm/byteorder.h>
17#include <uapi/linux/kernel.h>
18
19#define USHRT_MAX ((u16)(~0U))
20#define SHRT_MAX ((s16)(USHRT_MAX>>1))
21#define SHRT_MIN ((s16)(-SHRT_MAX - 1))
22#define INT_MAX ((int)(~0U>>1))
23#define INT_MIN (-INT_MAX - 1)
24#define UINT_MAX (~0U)
25#define LONG_MAX ((long)(~0UL>>1))
26#define LONG_MIN (-LONG_MAX - 1)
27#define ULONG_MAX (~0UL)
28#define LLONG_MAX ((long long)(~0ULL>>1))
29#define LLONG_MIN (-LLONG_MAX - 1)
30#define ULLONG_MAX (~0ULL)
31#define SIZE_MAX (~(size_t)0)
32#define PHYS_ADDR_MAX (~(phys_addr_t)0)
33
34#define U8_MAX ((u8)~0U)
35#define S8_MAX ((s8)(U8_MAX>>1))
36#define S8_MIN ((s8)(-S8_MAX - 1))
37#define U16_MAX ((u16)~0U)
38#define S16_MAX ((s16)(U16_MAX>>1))
39#define S16_MIN ((s16)(-S16_MAX - 1))
40#define U32_MAX ((u32)~0U)
41#define S32_MAX ((s32)(U32_MAX>>1))
42#define S32_MIN ((s32)(-S32_MAX - 1))
43#define U64_MAX ((u64)~0ULL)
44#define S64_MAX ((s64)(U64_MAX>>1))
45#define S64_MIN ((s64)(-S64_MAX - 1))
46
47#define STACK_MAGIC 0xdeadbeef
48
49/**
50 * REPEAT_BYTE - repeat the value @x multiple times as an unsigned long value
51 * @x: value to repeat
52 *
53 * NOTE: @x is not checked for > 0xff; larger values produce odd results.
54 */
55#define REPEAT_BYTE(x) ((~0ul / 0xff) * (x))
56
57/* @a is a power of 2 value */
58#define ALIGN(x, a) __ALIGN_KERNEL((x), (a))
59#define ALIGN_DOWN(x, a) __ALIGN_KERNEL((x) - ((a) - 1), (a))
60#define __ALIGN_MASK(x, mask) __ALIGN_KERNEL_MASK((x), (mask))
61#define PTR_ALIGN(p, a) ((typeof(p))ALIGN((unsigned long)(p), (a)))
62#define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0)
63
64/* generic data direction definitions */
65#define READ 0
66#define WRITE 1
67
68/**
69 * ARRAY_SIZE - get the number of elements in array @arr
70 * @arr: array to be sized
71 */
72#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
73
74#define u64_to_user_ptr(x) ( \
75{ \
76 typecheck(u64, x); \
77 (void __user *)(uintptr_t)x; \
78} \
79)
80
81/*
82 * This looks more complex than it should be. But we need to
83 * get the type for the ~ right in round_down (it needs to be
84 * as wide as the result!), and we want to evaluate the macro
85 * arguments just once each.
86 */
87#define __round_mask(x, y) ((__typeof__(x))((y)-1))
88#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
89#define round_down(x, y) ((x) & ~__round_mask(x, y))
90
91/**
92 * FIELD_SIZEOF - get the size of a struct's field
93 * @t: the target struct
94 * @f: the target struct's field
95 * Return: the size of @f in the struct definition without having a
96 * declared instance of @t.
97 */
98#define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
99
100#define DIV_ROUND_UP __KERNEL_DIV_ROUND_UP
101
102#define DIV_ROUND_DOWN_ULL(ll, d) \
103 ({ unsigned long long _tmp = (ll); do_div(_tmp, d); _tmp; })
104
105#define DIV_ROUND_UP_ULL(ll, d) DIV_ROUND_DOWN_ULL((ll) + (d) - 1, (d))
106
107#if BITS_PER_LONG == 32
108# define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d)
109#else
110# define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d)
111#endif
112
113/* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */
114#define roundup(x, y) ( \
115{ \
116 const typeof(y) __y = y; \
117 (((x) + (__y - 1)) / __y) * __y; \
118} \
119)
120#define rounddown(x, y) ( \
121{ \
122 typeof(x) __x = (x); \
123 __x - (__x % (y)); \
124} \
125)
126
127/*
128 * Divide positive or negative dividend by positive or negative divisor
129 * and round to closest integer. Result is undefined for negative
130 * divisors if the dividend variable type is unsigned and for negative
131 * dividends if the divisor variable type is unsigned.
132 */
133#define DIV_ROUND_CLOSEST(x, divisor)( \
134{ \
135 typeof(x) __x = x; \
136 typeof(divisor) __d = divisor; \
137 (((typeof(x))-1) > 0 || \
138 ((typeof(divisor))-1) > 0 || \
139 (((__x) > 0) == ((__d) > 0))) ? \
140 (((__x) + ((__d) / 2)) / (__d)) : \
141 (((__x) - ((__d) / 2)) / (__d)); \
142} \
143)
144/*
145 * Same as above but for u64 dividends. divisor must be a 32-bit
146 * number.
147 */
148#define DIV_ROUND_CLOSEST_ULL(x, divisor)( \
149{ \
150 typeof(divisor) __d = divisor; \
151 unsigned long long _tmp = (x) + (__d) / 2; \
152 do_div(_tmp, __d); \
153 _tmp; \
154} \
155)
156
157/*
158 * Multiplies an integer by a fraction, while avoiding unnecessary
159 * overflow or loss of precision.
160 */
161#define mult_frac(x, numer, denom)( \
162{ \
163 typeof(x) quot = (x) / (denom); \
164 typeof(x) rem = (x) % (denom); \
165 (quot * (numer)) + ((rem * (numer)) / (denom)); \
166} \
167)
168
169
170#define _RET_IP_ (unsigned long)__builtin_return_address(0)
171#define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; })
172
173#ifdef CONFIG_LBDAF
174# include <asm/div64.h>
175# define sector_div(a, b) do_div(a, b)
176#else
177# define sector_div(n, b)( \
178{ \
179 int _res; \
180 _res = (n) % (b); \
181 (n) /= (b); \
182 _res; \
183} \
184)
185#endif
186
187/**
188 * upper_32_bits - return bits 32-63 of a number
189 * @n: the number we're accessing
190 *
191 * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress
192 * the "right shift count >= width of type" warning when that quantity is
193 * 32-bits.
194 */
195#define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
196
197/**
198 * lower_32_bits - return bits 0-31 of a number
199 * @n: the number we're accessing
200 */
201#define lower_32_bits(n) ((u32)(n))
202
203struct completion;
204struct pt_regs;
205struct user;
206
207#ifdef CONFIG_PREEMPT_VOLUNTARY
208extern int _cond_resched(void);
209# define might_resched() _cond_resched()
210#else
211# define might_resched() do { } while (0)
212#endif
213
214#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
215 void ___might_sleep(const char *file, int line, int preempt_offset);
216 void __might_sleep(const char *file, int line, int preempt_offset);
217/**
218 * might_sleep - annotation for functions that can sleep
219 *
220 * this macro will print a stack trace if it is executed in an atomic
221 * context (spinlock, irq-handler, ...).
222 *
223 * This is a useful debugging help to be able to catch problems early and not
224 * be bitten later when the calling function happens to sleep when it is not
225 * supposed to.
226 */
227# define might_sleep() \
228 do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
229# define sched_annotate_sleep() (current->task_state_change = 0)
230#else
231 static inline void ___might_sleep(const char *file, int line,
232 int preempt_offset) { }
233 static inline void __might_sleep(const char *file, int line,
234 int preempt_offset) { }
235# define might_sleep() do { might_resched(); } while (0)
236# define sched_annotate_sleep() do { } while (0)
237#endif
238
239#define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
240
241/**
242 * abs - return absolute value of an argument
243 * @x: the value. If it is unsigned type, it is converted to signed type first.
244 * char is treated as if it was signed (regardless of whether it really is)
245 * but the macro's return type is preserved as char.
246 *
247 * Return: an absolute value of x.
248 */
249#define abs(x) __abs_choose_expr(x, long long, \
250 __abs_choose_expr(x, long, \
251 __abs_choose_expr(x, int, \
252 __abs_choose_expr(x, short, \
253 __abs_choose_expr(x, char, \
254 __builtin_choose_expr( \
255 __builtin_types_compatible_p(typeof(x), char), \
256 (char)({ signed char __x = (x); __x<0?-__x:__x; }), \
257 ((void)0)))))))
258
259#define __abs_choose_expr(x, type, other) __builtin_choose_expr( \
260 __builtin_types_compatible_p(typeof(x), signed type) || \
261 __builtin_types_compatible_p(typeof(x), unsigned type), \
262 ({ signed type __x = (x); __x < 0 ? -__x : __x; }), other)
263
264/**
265 * reciprocal_scale - "scale" a value into range [0, ep_ro)
266 * @val: value
267 * @ep_ro: right open interval endpoint
268 *
269 * Perform a "reciprocal multiplication" in order to "scale" a value into
270 * range [0, @ep_ro), where the upper interval endpoint is right-open.
271 * This is useful, e.g. for accessing a index of an array containing
272 * @ep_ro elements, for example. Think of it as sort of modulus, only that
273 * the result isn't that of modulo. ;) Note that if initial input is a
274 * small value, then result will return 0.
275 *
276 * Return: a result based on @val in interval [0, @ep_ro).
277 */
278static inline u32 reciprocal_scale(u32 val, u32 ep_ro)
279{
280 return (u32)(((u64) val * ep_ro) >> 32);
281}
282
283#if defined(CONFIG_MMU) && \
284 (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP))
285#define might_fault() __might_fault(__FILE__, __LINE__)
286void __might_fault(const char *file, int line);
287#else
288static inline void might_fault(void) { }
289#endif
290
291extern struct atomic_notifier_head panic_notifier_list;
292extern long (*panic_blink)(int state);
293__printf(1, 2)
294void panic(const char *fmt, ...) __noreturn __cold;
295void nmi_panic(struct pt_regs *regs, const char *msg);
296extern void oops_enter(void);
297extern void oops_exit(void);
298void print_oops_end_marker(void);
299extern int oops_may_print(void);
300void do_exit(long error_code) __noreturn;
301void complete_and_exit(struct completion *, long) __noreturn;
302
303#ifdef CONFIG_ARCH_HAS_REFCOUNT
304void refcount_error_report(struct pt_regs *regs, const char *err);
305#else
306static inline void refcount_error_report(struct pt_regs *regs, const char *err)
307{ }
308#endif
309
310/* Internal, do not use. */
311int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
312int __must_check _kstrtol(const char *s, unsigned int base, long *res);
313
314int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
315int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
316
317/**
318 * kstrtoul - convert a string to an unsigned long
319 * @s: The start of the string. The string must be null-terminated, and may also
320 * include a single newline before its terminating null. The first character
321 * may also be a plus sign, but not a minus sign.
322 * @base: The number base to use. The maximum supported base is 16. If base is
323 * given as 0, then the base of the string is automatically detected with the
324 * conventional semantics - If it begins with 0x the number will be parsed as a
325 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
326 * parsed as an octal number. Otherwise it will be parsed as a decimal.
327 * @res: Where to write the result of the conversion on success.
328 *
329 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
330 * Used as a replacement for the obsolete simple_strtoull. Return code must
331 * be checked.
332*/
333static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
334{
335 /*
336 * We want to shortcut function call, but
337 * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
338 */
339 if (sizeof(unsigned long) == sizeof(unsigned long long) &&
340 __alignof__(unsigned long) == __alignof__(unsigned long long))
341 return kstrtoull(s, base, (unsigned long long *)res);
342 else
343 return _kstrtoul(s, base, res);
344}
345
346/**
347 * kstrtol - convert a string to a long
348 * @s: The start of the string. The string must be null-terminated, and may also
349 * include a single newline before its terminating null. The first character
350 * may also be a plus sign or a minus sign.
351 * @base: The number base to use. The maximum supported base is 16. If base is
352 * given as 0, then the base of the string is automatically detected with the
353 * conventional semantics - If it begins with 0x the number will be parsed as a
354 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
355 * parsed as an octal number. Otherwise it will be parsed as a decimal.
356 * @res: Where to write the result of the conversion on success.
357 *
358 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
359 * Used as a replacement for the obsolete simple_strtoull. Return code must
360 * be checked.
361 */
362static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
363{
364 /*
365 * We want to shortcut function call, but
366 * __builtin_types_compatible_p(long, long long) = 0.
367 */
368 if (sizeof(long) == sizeof(long long) &&
369 __alignof__(long) == __alignof__(long long))
370 return kstrtoll(s, base, (long long *)res);
371 else
372 return _kstrtol(s, base, res);
373}
374
375int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
376int __must_check kstrtoint(const char *s, unsigned int base, int *res);
377
378static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
379{
380 return kstrtoull(s, base, res);
381}
382
383static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
384{
385 return kstrtoll(s, base, res);
386}
387
388static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
389{
390 return kstrtouint(s, base, res);
391}
392
393static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
394{
395 return kstrtoint(s, base, res);
396}
397
398int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
399int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
400int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
401int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
402int __must_check kstrtobool(const char *s, bool *res);
403
404int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
405int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
406int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
407int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
408int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
409int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
410int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
411int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
412int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
413int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
414int __must_check kstrtobool_from_user(const char __user *s, size_t count, bool *res);
415
416static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
417{
418 return kstrtoull_from_user(s, count, base, res);
419}
420
421static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
422{
423 return kstrtoll_from_user(s, count, base, res);
424}
425
426static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
427{
428 return kstrtouint_from_user(s, count, base, res);
429}
430
431static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
432{
433 return kstrtoint_from_user(s, count, base, res);
434}
435
436/* Obsolete, do not use. Use kstrto<foo> instead */
437
438extern unsigned long simple_strtoul(const char *,char **,unsigned int);
439extern long simple_strtol(const char *,char **,unsigned int);
440extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
441extern long long simple_strtoll(const char *,char **,unsigned int);
442
443extern int num_to_str(char *buf, int size,
444 unsigned long long num, unsigned int width);
445
446/* lib/printf utilities */
447
448extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
449extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
450extern __printf(3, 4)
451int snprintf(char *buf, size_t size, const char *fmt, ...);
452extern __printf(3, 0)
453int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
454extern __printf(3, 4)
455int scnprintf(char *buf, size_t size, const char *fmt, ...);
456extern __printf(3, 0)
457int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
458extern __printf(2, 3) __malloc
459char *kasprintf(gfp_t gfp, const char *fmt, ...);
460extern __printf(2, 0) __malloc
461char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
462extern __printf(2, 0)
463const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list args);
464
465extern __scanf(2, 3)
466int sscanf(const char *, const char *, ...);
467extern __scanf(2, 0)
468int vsscanf(const char *, const char *, va_list);
469
470extern int get_option(char **str, int *pint);
471extern char *get_options(const char *str, int nints, int *ints);
472extern unsigned long long memparse(const char *ptr, char **retptr);
473extern bool parse_option_str(const char *str, const char *option);
474extern char *next_arg(char *args, char **param, char **val);
475
476extern int core_kernel_text(unsigned long addr);
477extern int init_kernel_text(unsigned long addr);
478extern int core_kernel_data(unsigned long addr);
479extern int __kernel_text_address(unsigned long addr);
480extern int kernel_text_address(unsigned long addr);
481extern int func_ptr_is_kernel_text(void *ptr);
482
483unsigned long int_sqrt(unsigned long);
484
485#if BITS_PER_LONG < 64
486u32 int_sqrt64(u64 x);
487#else
488static inline u32 int_sqrt64(u64 x)
489{
490 return (u32)int_sqrt(x);
491}
492#endif
493
494extern void bust_spinlocks(int yes);
495extern int oops_in_progress; /* If set, an oops, panic(), BUG() or die() is in progress */
496extern int panic_timeout;
497extern int panic_on_oops;
498extern int panic_on_unrecovered_nmi;
499extern int panic_on_io_nmi;
500extern int panic_on_warn;
501extern int sysctl_panic_on_rcu_stall;
502extern int sysctl_panic_on_stackoverflow;
503
504extern bool crash_kexec_post_notifiers;
505
506/*
507 * panic_cpu is used for synchronizing panic() and crash_kexec() execution. It
508 * holds a CPU number which is executing panic() currently. A value of
509 * PANIC_CPU_INVALID means no CPU has entered panic() or crash_kexec().
510 */
511extern atomic_t panic_cpu;
512#define PANIC_CPU_INVALID -1
513
514/*
515 * Only to be used by arch init code. If the user over-wrote the default
516 * CONFIG_PANIC_TIMEOUT, honor it.
517 */
518static inline void set_arch_panic_timeout(int timeout, int arch_default_timeout)
519{
520 if (panic_timeout == arch_default_timeout)
521 panic_timeout = timeout;
522}
523extern const char *print_tainted(void);
524enum lockdep_ok {
525 LOCKDEP_STILL_OK,
526 LOCKDEP_NOW_UNRELIABLE
527};
528extern void add_taint(unsigned flag, enum lockdep_ok);
529extern int test_taint(unsigned flag);
530extern unsigned long get_taint(void);
531extern int root_mountflags;
532
533extern bool early_boot_irqs_disabled;
534
535/*
536 * Values used for system_state. Ordering of the states must not be changed
537 * as code checks for <, <=, >, >= STATE.
538 */
539extern enum system_states {
540 SYSTEM_BOOTING,
541 SYSTEM_SCHEDULING,
542 SYSTEM_RUNNING,
543 SYSTEM_HALT,
544 SYSTEM_POWER_OFF,
545 SYSTEM_RESTART,
546 SYSTEM_SUSPEND,
547} system_state;
548
549/* This cannot be an enum because some may be used in assembly source. */
550#define TAINT_PROPRIETARY_MODULE 0
551#define TAINT_FORCED_MODULE 1
552#define TAINT_CPU_OUT_OF_SPEC 2
553#define TAINT_FORCED_RMMOD 3
554#define TAINT_MACHINE_CHECK 4
555#define TAINT_BAD_PAGE 5
556#define TAINT_USER 6
557#define TAINT_DIE 7
558#define TAINT_OVERRIDDEN_ACPI_TABLE 8
559#define TAINT_WARN 9
560#define TAINT_CRAP 10
561#define TAINT_FIRMWARE_WORKAROUND 11
562#define TAINT_OOT_MODULE 12
563#define TAINT_UNSIGNED_MODULE 13
564#define TAINT_SOFTLOCKUP 14
565#define TAINT_LIVEPATCH 15
566#define TAINT_AUX 16
567#define TAINT_RANDSTRUCT 17
568#define TAINT_FLAGS_COUNT 18
569
570struct taint_flag {
571 char c_true; /* character printed when tainted */
572 char c_false; /* character printed when not tainted */
573 bool module; /* also show as a per-module taint flag */
574};
575
576extern const struct taint_flag taint_flags[TAINT_FLAGS_COUNT];
577
578extern const char hex_asc[];
579#define hex_asc_lo(x) hex_asc[((x) & 0x0f)]
580#define hex_asc_hi(x) hex_asc[((x) & 0xf0) >> 4]
581
582static inline char *hex_byte_pack(char *buf, u8 byte)
583{
584 *buf++ = hex_asc_hi(byte);
585 *buf++ = hex_asc_lo(byte);
586 return buf;
587}
588
589extern const char hex_asc_upper[];
590#define hex_asc_upper_lo(x) hex_asc_upper[((x) & 0x0f)]
591#define hex_asc_upper_hi(x) hex_asc_upper[((x) & 0xf0) >> 4]
592
593static inline char *hex_byte_pack_upper(char *buf, u8 byte)
594{
595 *buf++ = hex_asc_upper_hi(byte);
596 *buf++ = hex_asc_upper_lo(byte);
597 return buf;
598}
599
600extern int hex_to_bin(char ch);
601extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
602extern char *bin2hex(char *dst, const void *src, size_t count);
603
604bool mac_pton(const char *s, u8 *mac);
605
606/*
607 * General tracing related utility functions - trace_printk(),
608 * tracing_on/tracing_off and tracing_start()/tracing_stop
609 *
610 * Use tracing_on/tracing_off when you want to quickly turn on or off
611 * tracing. It simply enables or disables the recording of the trace events.
612 * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
613 * file, which gives a means for the kernel and userspace to interact.
614 * Place a tracing_off() in the kernel where you want tracing to end.
615 * From user space, examine the trace, and then echo 1 > tracing_on
616 * to continue tracing.
617 *
618 * tracing_stop/tracing_start has slightly more overhead. It is used
619 * by things like suspend to ram where disabling the recording of the
620 * trace is not enough, but tracing must actually stop because things
621 * like calling smp_processor_id() may crash the system.
622 *
623 * Most likely, you want to use tracing_on/tracing_off.
624 */
625
626enum ftrace_dump_mode {
627 DUMP_NONE,
628 DUMP_ALL,
629 DUMP_ORIG,
630};
631
632#ifdef CONFIG_TRACING
633void tracing_on(void);
634void tracing_off(void);
635int tracing_is_on(void);
636void tracing_snapshot(void);
637void tracing_snapshot_alloc(void);
638
639extern void tracing_start(void);
640extern void tracing_stop(void);
641
642static inline __printf(1, 2)
643void ____trace_printk_check_format(const char *fmt, ...)
644{
645}
646#define __trace_printk_check_format(fmt, args...) \
647do { \
648 if (0) \
649 ____trace_printk_check_format(fmt, ##args); \
650} while (0)
651
652/**
653 * trace_printk - printf formatting in the ftrace buffer
654 * @fmt: the printf format for printing
655 *
656 * Note: __trace_printk is an internal function for trace_printk() and
657 * the @ip is passed in via the trace_printk() macro.
658 *
659 * This function allows a kernel developer to debug fast path sections
660 * that printk is not appropriate for. By scattering in various
661 * printk like tracing in the code, a developer can quickly see
662 * where problems are occurring.
663 *
664 * This is intended as a debugging tool for the developer only.
665 * Please refrain from leaving trace_printks scattered around in
666 * your code. (Extra memory is used for special buffers that are
667 * allocated when trace_printk() is used.)
668 *
669 * A little optimization trick is done here. If there's only one
670 * argument, there's no need to scan the string for printf formats.
671 * The trace_puts() will suffice. But how can we take advantage of
672 * using trace_puts() when trace_printk() has only one argument?
673 * By stringifying the args and checking the size we can tell
674 * whether or not there are args. __stringify((__VA_ARGS__)) will
675 * turn into "()\0" with a size of 3 when there are no args, anything
676 * else will be bigger. All we need to do is define a string to this,
677 * and then take its size and compare to 3. If it's bigger, use
678 * do_trace_printk() otherwise, optimize it to trace_puts(). Then just
679 * let gcc optimize the rest.
680 */
681
682#define trace_printk(fmt, ...) \
683do { \
684 char _______STR[] = __stringify((__VA_ARGS__)); \
685 if (sizeof(_______STR) > 3) \
686 do_trace_printk(fmt, ##__VA_ARGS__); \
687 else \
688 trace_puts(fmt); \
689} while (0)
690
691#define do_trace_printk(fmt, args...) \
692do { \
693 static const char *trace_printk_fmt __used \
694 __attribute__((section("__trace_printk_fmt"))) = \
695 __builtin_constant_p(fmt) ? fmt : NULL; \
696 \
697 __trace_printk_check_format(fmt, ##args); \
698 \
699 if (__builtin_constant_p(fmt)) \
700 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \
701 else \
702 __trace_printk(_THIS_IP_, fmt, ##args); \
703} while (0)
704
705extern __printf(2, 3)
706int __trace_bprintk(unsigned long ip, const char *fmt, ...);
707
708extern __printf(2, 3)
709int __trace_printk(unsigned long ip, const char *fmt, ...);
710
711/**
712 * trace_puts - write a string into the ftrace buffer
713 * @str: the string to record
714 *
715 * Note: __trace_bputs is an internal function for trace_puts and
716 * the @ip is passed in via the trace_puts macro.
717 *
718 * This is similar to trace_printk() but is made for those really fast
719 * paths that a developer wants the least amount of "Heisenbug" effects,
720 * where the processing of the print format is still too much.
721 *
722 * This function allows a kernel developer to debug fast path sections
723 * that printk is not appropriate for. By scattering in various
724 * printk like tracing in the code, a developer can quickly see
725 * where problems are occurring.
726 *
727 * This is intended as a debugging tool for the developer only.
728 * Please refrain from leaving trace_puts scattered around in
729 * your code. (Extra memory is used for special buffers that are
730 * allocated when trace_puts() is used.)
731 *
732 * Returns: 0 if nothing was written, positive # if string was.
733 * (1 when __trace_bputs is used, strlen(str) when __trace_puts is used)
734 */
735
736#define trace_puts(str) ({ \
737 static const char *trace_printk_fmt __used \
738 __attribute__((section("__trace_printk_fmt"))) = \
739 __builtin_constant_p(str) ? str : NULL; \
740 \
741 if (__builtin_constant_p(str)) \
742 __trace_bputs(_THIS_IP_, trace_printk_fmt); \
743 else \
744 __trace_puts(_THIS_IP_, str, strlen(str)); \
745})
746extern int __trace_bputs(unsigned long ip, const char *str);
747extern int __trace_puts(unsigned long ip, const char *str, int size);
748
749extern void trace_dump_stack(int skip);
750
751/*
752 * The double __builtin_constant_p is because gcc will give us an error
753 * if we try to allocate the static variable to fmt if it is not a
754 * constant. Even with the outer if statement.
755 */
756#define ftrace_vprintk(fmt, vargs) \
757do { \
758 if (__builtin_constant_p(fmt)) { \
759 static const char *trace_printk_fmt __used \
760 __attribute__((section("__trace_printk_fmt"))) = \
761 __builtin_constant_p(fmt) ? fmt : NULL; \
762 \
763 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs); \
764 } else \
765 __ftrace_vprintk(_THIS_IP_, fmt, vargs); \
766} while (0)
767
768extern __printf(2, 0) int
769__ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
770
771extern __printf(2, 0) int
772__ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
773
774extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
775#else
776static inline void tracing_start(void) { }
777static inline void tracing_stop(void) { }
778static inline void trace_dump_stack(int skip) { }
779
780static inline void tracing_on(void) { }
781static inline void tracing_off(void) { }
782static inline int tracing_is_on(void) { return 0; }
783static inline void tracing_snapshot(void) { }
784static inline void tracing_snapshot_alloc(void) { }
785
786static inline __printf(1, 2)
787int trace_printk(const char *fmt, ...)
788{
789 return 0;
790}
791static __printf(1, 0) inline int
792ftrace_vprintk(const char *fmt, va_list ap)
793{
794 return 0;
795}
796static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
797#endif /* CONFIG_TRACING */
798
799/*
800 * min()/max()/clamp() macros must accomplish three things:
801 *
802 * - avoid multiple evaluations of the arguments (so side-effects like
803 * "x++" happen only once) when non-constant.
804 * - perform strict type-checking (to generate warnings instead of
805 * nasty runtime surprises). See the "unnecessary" pointer comparison
806 * in __typecheck().
807 * - retain result as a constant expressions when called with only
808 * constant expressions (to avoid tripping VLA warnings in stack
809 * allocation usage).
810 */
811#define __typecheck(x, y) \
812 (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
813
814/*
815 * This returns a constant expression while determining if an argument is
816 * a constant expression, most importantly without evaluating the argument.
817 * Glory to Martin Uecker <Martin.Uecker@med.uni-goettingen.de>
818 */
819#define __is_constexpr(x) \
820 (sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8)))
821
822#define __no_side_effects(x, y) \
823 (__is_constexpr(x) && __is_constexpr(y))
824
825#define __safe_cmp(x, y) \
826 (__typecheck(x, y) && __no_side_effects(x, y))
827
828#define __cmp(x, y, op) ((x) op (y) ? (x) : (y))
829
830#define __cmp_once(x, y, unique_x, unique_y, op) ({ \
831 typeof(x) unique_x = (x); \
832 typeof(y) unique_y = (y); \
833 __cmp(unique_x, unique_y, op); })
834
835#define __careful_cmp(x, y, op) \
836 __builtin_choose_expr(__safe_cmp(x, y), \
837 __cmp(x, y, op), \
838 __cmp_once(x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y), op))
839
840/**
841 * min - return minimum of two values of the same or compatible types
842 * @x: first value
843 * @y: second value
844 */
845#define min(x, y) __careful_cmp(x, y, <)
846
847/**
848 * max - return maximum of two values of the same or compatible types
849 * @x: first value
850 * @y: second value
851 */
852#define max(x, y) __careful_cmp(x, y, >)
853
854/**
855 * min3 - return minimum of three values
856 * @x: first value
857 * @y: second value
858 * @z: third value
859 */
860#define min3(x, y, z) min((typeof(x))min(x, y), z)
861
862/**
863 * max3 - return maximum of three values
864 * @x: first value
865 * @y: second value
866 * @z: third value
867 */
868#define max3(x, y, z) max((typeof(x))max(x, y), z)
869
870/**
871 * min_not_zero - return the minimum that is _not_ zero, unless both are zero
872 * @x: value1
873 * @y: value2
874 */
875#define min_not_zero(x, y) ({ \
876 typeof(x) __x = (x); \
877 typeof(y) __y = (y); \
878 __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
879
880/**
881 * clamp - return a value clamped to a given range with strict typechecking
882 * @val: current value
883 * @lo: lowest allowable value
884 * @hi: highest allowable value
885 *
886 * This macro does strict typechecking of @lo/@hi to make sure they are of the
887 * same type as @val. See the unnecessary pointer comparisons.
888 */
889#define clamp(val, lo, hi) min((typeof(val))max(val, lo), hi)
890
891/*
892 * ..and if you can't take the strict
893 * types, you can specify one yourself.
894 *
895 * Or not use min/max/clamp at all, of course.
896 */
897
898/**
899 * min_t - return minimum of two values, using the specified type
900 * @type: data type to use
901 * @x: first value
902 * @y: second value
903 */
904#define min_t(type, x, y) __careful_cmp((type)(x), (type)(y), <)
905
906/**
907 * max_t - return maximum of two values, using the specified type
908 * @type: data type to use
909 * @x: first value
910 * @y: second value
911 */
912#define max_t(type, x, y) __careful_cmp((type)(x), (type)(y), >)
913
914/**
915 * clamp_t - return a value clamped to a given range using a given type
916 * @type: the type of variable to use
917 * @val: current value
918 * @lo: minimum allowable value
919 * @hi: maximum allowable value
920 *
921 * This macro does no typechecking and uses temporary variables of type
922 * @type to make all the comparisons.
923 */
924#define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi)
925
926/**
927 * clamp_val - return a value clamped to a given range using val's type
928 * @val: current value
929 * @lo: minimum allowable value
930 * @hi: maximum allowable value
931 *
932 * This macro does no typechecking and uses temporary variables of whatever
933 * type the input argument @val is. This is useful when @val is an unsigned
934 * type and @lo and @hi are literals that will otherwise be assigned a signed
935 * integer type.
936 */
937#define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)
938
939
940/**
941 * swap - swap values of @a and @b
942 * @a: first value
943 * @b: second value
944 */
945#define swap(a, b) \
946 do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
947
948/* This counts to 12. Any more, it will return 13th argument. */
949#define __COUNT_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _n, X...) _n
950#define COUNT_ARGS(X...) __COUNT_ARGS(, ##X, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
951
952#define __CONCAT(a, b) a ## b
953#define CONCATENATE(a, b) __CONCAT(a, b)
954
955/**
956 * container_of - cast a member of a structure out to the containing structure
957 * @ptr: the pointer to the member.
958 * @type: the type of the container struct this is embedded in.
959 * @member: the name of the member within the struct.
960 *
961 */
962#define container_of(ptr, type, member) ({ \
963 void *__mptr = (void *)(ptr); \
964 BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
965 !__same_type(*(ptr), void), \
966 "pointer type mismatch in container_of()"); \
967 ((type *)(__mptr - offsetof(type, member))); })
968
969/**
970 * container_of_safe - cast a member of a structure out to the containing structure
971 * @ptr: the pointer to the member.
972 * @type: the type of the container struct this is embedded in.
973 * @member: the name of the member within the struct.
974 *
975 * If IS_ERR_OR_NULL(ptr), ptr is returned unchanged.
976 */
977#define container_of_safe(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 IS_ERR_OR_NULL(__mptr) ? ERR_CAST(__mptr) : \
983 ((type *)(__mptr - offsetof(type, member))); })
984
985/* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
986#ifdef CONFIG_FTRACE_MCOUNT_RECORD
987# define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
988#endif
989
990/* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */
991#define VERIFY_OCTAL_PERMISSIONS(perms) \
992 (BUILD_BUG_ON_ZERO((perms) < 0) + \
993 BUILD_BUG_ON_ZERO((perms) > 0777) + \
994 /* USER_READABLE >= GROUP_READABLE >= OTHER_READABLE */ \
995 BUILD_BUG_ON_ZERO((((perms) >> 6) & 4) < (((perms) >> 3) & 4)) + \
996 BUILD_BUG_ON_ZERO((((perms) >> 3) & 4) < ((perms) & 4)) + \
997 /* USER_WRITABLE >= GROUP_WRITABLE */ \
998 BUILD_BUG_ON_ZERO((((perms) >> 6) & 2) < (((perms) >> 3) & 2)) + \
999 /* OTHER_WRITABLE? Generally considered a bad idea. */ \
1000 BUILD_BUG_ON_ZERO((perms) & 2) + \
1001 (perms))
1002#endif
1003