projects/linux·blob v5.12-rc2 · refs

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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_KERNEL_H
3#define _LINUX_KERNEL_H
4
5#include <stdarg.h>
6#include <linux/limits.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/math.h>
14#include <linux/minmax.h>
15#include <linux/typecheck.h>
16#include <linux/printk.h>
17#include <linux/build_bug.h>
18#include <linux/static_call_types.h>
19#include <asm/byteorder.h>
20
21#include <uapi/linux/kernel.h>
22
23#define STACK_MAGIC 0xdeadbeef
24
25/**
26 * REPEAT_BYTE - repeat the value @x multiple times as an unsigned long value
27 * @x: value to repeat
28 *
29 * NOTE: @x is not checked for > 0xff; larger values produce odd results.
30 */
31#define REPEAT_BYTE(x) ((~0ul / 0xff) * (x))
32
33/* @a is a power of 2 value */
34#define ALIGN(x, a) __ALIGN_KERNEL((x), (a))
35#define ALIGN_DOWN(x, a) __ALIGN_KERNEL((x) - ((a) - 1), (a))
36#define __ALIGN_MASK(x, mask) __ALIGN_KERNEL_MASK((x), (mask))
37#define PTR_ALIGN(p, a) ((typeof(p))ALIGN((unsigned long)(p), (a)))
38#define PTR_ALIGN_DOWN(p, a) ((typeof(p))ALIGN_DOWN((unsigned long)(p), (a)))
39#define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0)
40
41/* generic data direction definitions */
42#define READ 0
43#define WRITE 1
44
45/**
46 * ARRAY_SIZE - get the number of elements in array @arr
47 * @arr: array to be sized
48 */
49#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
50
51#define u64_to_user_ptr(x) ( \
52{ \
53 typecheck(u64, (x)); \
54 (void __user *)(uintptr_t)(x); \
55} \
56)
57
58#define typeof_member(T, m) typeof(((T*)0)->m)
59
60#define _RET_IP_ (unsigned long)__builtin_return_address(0)
61#define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; })
62
63/**
64 * upper_32_bits - return bits 32-63 of a number
65 * @n: the number we're accessing
66 *
67 * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress
68 * the "right shift count >= width of type" warning when that quantity is
69 * 32-bits.
70 */
71#define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
72
73/**
74 * lower_32_bits - return bits 0-31 of a number
75 * @n: the number we're accessing
76 */
77#define lower_32_bits(n) ((u32)((n) & 0xffffffff))
78
79struct completion;
80struct pt_regs;
81struct user;
82
83#ifdef CONFIG_PREEMPT_VOLUNTARY
84
85extern int __cond_resched(void);
86# define might_resched() __cond_resched()
87
88#elif defined(CONFIG_PREEMPT_DYNAMIC)
89
90extern int __cond_resched(void);
91
92DECLARE_STATIC_CALL(might_resched, __cond_resched);
93
94static __always_inline void might_resched(void)
95{
96 static_call_mod(might_resched)();
97}
98
99#else
100
101# define might_resched() do { } while (0)
102
103#endif /* CONFIG_PREEMPT_* */
104
105#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
106extern void ___might_sleep(const char *file, int line, int preempt_offset);
107extern void __might_sleep(const char *file, int line, int preempt_offset);
108extern void __cant_sleep(const char *file, int line, int preempt_offset);
109extern void __cant_migrate(const char *file, int line);
110
111/**
112 * might_sleep - annotation for functions that can sleep
113 *
114 * this macro will print a stack trace if it is executed in an atomic
115 * context (spinlock, irq-handler, ...). Additional sections where blocking is
116 * not allowed can be annotated with non_block_start() and non_block_end()
117 * pairs.
118 *
119 * This is a useful debugging help to be able to catch problems early and not
120 * be bitten later when the calling function happens to sleep when it is not
121 * supposed to.
122 */
123# define might_sleep() \
124 do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
125/**
126 * cant_sleep - annotation for functions that cannot sleep
127 *
128 * this macro will print a stack trace if it is executed with preemption enabled
129 */
130# define cant_sleep() \
131 do { __cant_sleep(__FILE__, __LINE__, 0); } while (0)
132# define sched_annotate_sleep() (current->task_state_change = 0)
133
134/**
135 * cant_migrate - annotation for functions that cannot migrate
136 *
137 * Will print a stack trace if executed in code which is migratable
138 */
139# define cant_migrate() \
140 do { \
141 if (IS_ENABLED(CONFIG_SMP)) \
142 __cant_migrate(__FILE__, __LINE__); \
143 } while (0)
144
145/**
146 * non_block_start - annotate the start of section where sleeping is prohibited
147 *
148 * This is on behalf of the oom reaper, specifically when it is calling the mmu
149 * notifiers. The problem is that if the notifier were to block on, for example,
150 * mutex_lock() and if the process which holds that mutex were to perform a
151 * sleeping memory allocation, the oom reaper is now blocked on completion of
152 * that memory allocation. Other blocking calls like wait_event() pose similar
153 * issues.
154 */
155# define non_block_start() (current->non_block_count++)
156/**
157 * non_block_end - annotate the end of section where sleeping is prohibited
158 *
159 * Closes a section opened by non_block_start().
160 */
161# define non_block_end() WARN_ON(current->non_block_count-- == 0)
162#else
163 static inline void ___might_sleep(const char *file, int line,
164 int preempt_offset) { }
165 static inline void __might_sleep(const char *file, int line,
166 int preempt_offset) { }
167# define might_sleep() do { might_resched(); } while (0)
168# define cant_sleep() do { } while (0)
169# define cant_migrate() do { } while (0)
170# define sched_annotate_sleep() do { } while (0)
171# define non_block_start() do { } while (0)
172# define non_block_end() do { } while (0)
173#endif
174
175#define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
176
177#if defined(CONFIG_MMU) && \
178 (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP))
179#define might_fault() __might_fault(__FILE__, __LINE__)
180void __might_fault(const char *file, int line);
181#else
182static inline void might_fault(void) { }
183#endif
184
185extern struct atomic_notifier_head panic_notifier_list;
186extern long (*panic_blink)(int state);
187__printf(1, 2)
188void panic(const char *fmt, ...) __noreturn __cold;
189void nmi_panic(struct pt_regs *regs, const char *msg);
190extern void oops_enter(void);
191extern void oops_exit(void);
192extern bool oops_may_print(void);
193void do_exit(long error_code) __noreturn;
194void complete_and_exit(struct completion *, long) __noreturn;
195
196/* Internal, do not use. */
197int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
198int __must_check _kstrtol(const char *s, unsigned int base, long *res);
199
200int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
201int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
202
203/**
204 * kstrtoul - convert a string to an unsigned long
205 * @s: The start of the string. The string must be null-terminated, and may also
206 * include a single newline before its terminating null. The first character
207 * may also be a plus sign, but not a minus sign.
208 * @base: The number base to use. The maximum supported base is 16. If base is
209 * given as 0, then the base of the string is automatically detected with the
210 * conventional semantics - If it begins with 0x the number will be parsed as a
211 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
212 * parsed as an octal number. Otherwise it will be parsed as a decimal.
213 * @res: Where to write the result of the conversion on success.
214 *
215 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
216 * Preferred over simple_strtoul(). Return code must be checked.
217*/
218static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
219{
220 /*
221 * We want to shortcut function call, but
222 * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
223 */
224 if (sizeof(unsigned long) == sizeof(unsigned long long) &&
225 __alignof__(unsigned long) == __alignof__(unsigned long long))
226 return kstrtoull(s, base, (unsigned long long *)res);
227 else
228 return _kstrtoul(s, base, res);
229}
230
231/**
232 * kstrtol - convert a string to a long
233 * @s: The start of the string. The string must be null-terminated, and may also
234 * include a single newline before its terminating null. The first character
235 * may also be a plus sign or a minus sign.
236 * @base: The number base to use. The maximum supported base is 16. If base is
237 * given as 0, then the base of the string is automatically detected with the
238 * conventional semantics - If it begins with 0x the number will be parsed as a
239 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
240 * parsed as an octal number. Otherwise it will be parsed as a decimal.
241 * @res: Where to write the result of the conversion on success.
242 *
243 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
244 * Preferred over simple_strtol(). Return code must be checked.
245 */
246static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
247{
248 /*
249 * We want to shortcut function call, but
250 * __builtin_types_compatible_p(long, long long) = 0.
251 */
252 if (sizeof(long) == sizeof(long long) &&
253 __alignof__(long) == __alignof__(long long))
254 return kstrtoll(s, base, (long long *)res);
255 else
256 return _kstrtol(s, base, res);
257}
258
259int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
260int __must_check kstrtoint(const char *s, unsigned int base, int *res);
261
262static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
263{
264 return kstrtoull(s, base, res);
265}
266
267static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
268{
269 return kstrtoll(s, base, res);
270}
271
272static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
273{
274 return kstrtouint(s, base, res);
275}
276
277static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
278{
279 return kstrtoint(s, base, res);
280}
281
282int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
283int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
284int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
285int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
286int __must_check kstrtobool(const char *s, bool *res);
287
288int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
289int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
290int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
291int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
292int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
293int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
294int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
295int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
296int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
297int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
298int __must_check kstrtobool_from_user(const char __user *s, size_t count, bool *res);
299
300static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
301{
302 return kstrtoull_from_user(s, count, base, res);
303}
304
305static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
306{
307 return kstrtoll_from_user(s, count, base, res);
308}
309
310static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
311{
312 return kstrtouint_from_user(s, count, base, res);
313}
314
315static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
316{
317 return kstrtoint_from_user(s, count, base, res);
318}
319
320/*
321 * Use kstrto<foo> instead.
322 *
323 * NOTE: simple_strto<foo> does not check for the range overflow and,
324 * depending on the input, may give interesting results.
325 *
326 * Use these functions if and only if you cannot use kstrto<foo>, because
327 * the conversion ends on the first non-digit character, which may be far
328 * beyond the supported range. It might be useful to parse the strings like
329 * 10x50 or 12:21 without altering original string or temporary buffer in use.
330 * Keep in mind above caveat.
331 */
332
333extern unsigned long simple_strtoul(const char *,char **,unsigned int);
334extern long simple_strtol(const char *,char **,unsigned int);
335extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
336extern long long simple_strtoll(const char *,char **,unsigned int);
337
338extern int num_to_str(char *buf, int size,
339 unsigned long long num, unsigned int width);
340
341/* lib/printf utilities */
342
343extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
344extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
345extern __printf(3, 4)
346int snprintf(char *buf, size_t size, const char *fmt, ...);
347extern __printf(3, 0)
348int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
349extern __printf(3, 4)
350int scnprintf(char *buf, size_t size, const char *fmt, ...);
351extern __printf(3, 0)
352int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
353extern __printf(2, 3) __malloc
354char *kasprintf(gfp_t gfp, const char *fmt, ...);
355extern __printf(2, 0) __malloc
356char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
357extern __printf(2, 0)
358const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list args);
359
360extern __scanf(2, 3)
361int sscanf(const char *, const char *, ...);
362extern __scanf(2, 0)
363int vsscanf(const char *, const char *, va_list);
364
365extern int get_option(char **str, int *pint);
366extern char *get_options(const char *str, int nints, int *ints);
367extern unsigned long long memparse(const char *ptr, char **retptr);
368extern bool parse_option_str(const char *str, const char *option);
369extern char *next_arg(char *args, char **param, char **val);
370
371extern int core_kernel_text(unsigned long addr);
372extern int init_kernel_text(unsigned long addr);
373extern int core_kernel_data(unsigned long addr);
374extern int __kernel_text_address(unsigned long addr);
375extern int kernel_text_address(unsigned long addr);
376extern int func_ptr_is_kernel_text(void *ptr);
377
378#ifdef CONFIG_SMP
379extern unsigned int sysctl_oops_all_cpu_backtrace;
380#else
381#define sysctl_oops_all_cpu_backtrace 0
382#endif /* CONFIG_SMP */
383
384extern void bust_spinlocks(int yes);
385extern int panic_timeout;
386extern unsigned long panic_print;
387extern int panic_on_oops;
388extern int panic_on_unrecovered_nmi;
389extern int panic_on_io_nmi;
390extern int panic_on_warn;
391extern unsigned long panic_on_taint;
392extern bool panic_on_taint_nousertaint;
393extern int sysctl_panic_on_rcu_stall;
394extern int sysctl_max_rcu_stall_to_panic;
395extern int sysctl_panic_on_stackoverflow;
396
397extern bool crash_kexec_post_notifiers;
398
399/*
400 * panic_cpu is used for synchronizing panic() and crash_kexec() execution. It
401 * holds a CPU number which is executing panic() currently. A value of
402 * PANIC_CPU_INVALID means no CPU has entered panic() or crash_kexec().
403 */
404extern atomic_t panic_cpu;
405#define PANIC_CPU_INVALID -1
406
407/*
408 * Only to be used by arch init code. If the user over-wrote the default
409 * CONFIG_PANIC_TIMEOUT, honor it.
410 */
411static inline void set_arch_panic_timeout(int timeout, int arch_default_timeout)
412{
413 if (panic_timeout == arch_default_timeout)
414 panic_timeout = timeout;
415}
416extern const char *print_tainted(void);
417enum lockdep_ok {
418 LOCKDEP_STILL_OK,
419 LOCKDEP_NOW_UNRELIABLE
420};
421extern void add_taint(unsigned flag, enum lockdep_ok);
422extern int test_taint(unsigned flag);
423extern unsigned long get_taint(void);
424extern int root_mountflags;
425
426extern bool early_boot_irqs_disabled;
427
428/*
429 * Values used for system_state. Ordering of the states must not be changed
430 * as code checks for <, <=, >, >= STATE.
431 */
432extern enum system_states {
433 SYSTEM_BOOTING,
434 SYSTEM_SCHEDULING,
435 SYSTEM_RUNNING,
436 SYSTEM_HALT,
437 SYSTEM_POWER_OFF,
438 SYSTEM_RESTART,
439 SYSTEM_SUSPEND,
440} system_state;
441
442/* This cannot be an enum because some may be used in assembly source. */
443#define TAINT_PROPRIETARY_MODULE 0
444#define TAINT_FORCED_MODULE 1
445#define TAINT_CPU_OUT_OF_SPEC 2
446#define TAINT_FORCED_RMMOD 3
447#define TAINT_MACHINE_CHECK 4
448#define TAINT_BAD_PAGE 5
449#define TAINT_USER 6
450#define TAINT_DIE 7
451#define TAINT_OVERRIDDEN_ACPI_TABLE 8
452#define TAINT_WARN 9
453#define TAINT_CRAP 10
454#define TAINT_FIRMWARE_WORKAROUND 11
455#define TAINT_OOT_MODULE 12
456#define TAINT_UNSIGNED_MODULE 13
457#define TAINT_SOFTLOCKUP 14
458#define TAINT_LIVEPATCH 15
459#define TAINT_AUX 16
460#define TAINT_RANDSTRUCT 17
461#define TAINT_FLAGS_COUNT 18
462#define TAINT_FLAGS_MAX ((1UL << TAINT_FLAGS_COUNT) - 1)
463
464struct taint_flag {
465 char c_true; /* character printed when tainted */
466 char c_false; /* character printed when not tainted */
467 bool module; /* also show as a per-module taint flag */
468};
469
470extern const struct taint_flag taint_flags[TAINT_FLAGS_COUNT];
471
472extern const char hex_asc[];
473#define hex_asc_lo(x) hex_asc[((x) & 0x0f)]
474#define hex_asc_hi(x) hex_asc[((x) & 0xf0) >> 4]
475
476static inline char *hex_byte_pack(char *buf, u8 byte)
477{
478 *buf++ = hex_asc_hi(byte);
479 *buf++ = hex_asc_lo(byte);
480 return buf;
481}
482
483extern const char hex_asc_upper[];
484#define hex_asc_upper_lo(x) hex_asc_upper[((x) & 0x0f)]
485#define hex_asc_upper_hi(x) hex_asc_upper[((x) & 0xf0) >> 4]
486
487static inline char *hex_byte_pack_upper(char *buf, u8 byte)
488{
489 *buf++ = hex_asc_upper_hi(byte);
490 *buf++ = hex_asc_upper_lo(byte);
491 return buf;
492}
493
494extern int hex_to_bin(char ch);
495extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
496extern char *bin2hex(char *dst, const void *src, size_t count);
497
498bool mac_pton(const char *s, u8 *mac);
499
500/*
501 * General tracing related utility functions - trace_printk(),
502 * tracing_on/tracing_off and tracing_start()/tracing_stop
503 *
504 * Use tracing_on/tracing_off when you want to quickly turn on or off
505 * tracing. It simply enables or disables the recording of the trace events.
506 * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
507 * file, which gives a means for the kernel and userspace to interact.
508 * Place a tracing_off() in the kernel where you want tracing to end.
509 * From user space, examine the trace, and then echo 1 > tracing_on
510 * to continue tracing.
511 *
512 * tracing_stop/tracing_start has slightly more overhead. It is used
513 * by things like suspend to ram where disabling the recording of the
514 * trace is not enough, but tracing must actually stop because things
515 * like calling smp_processor_id() may crash the system.
516 *
517 * Most likely, you want to use tracing_on/tracing_off.
518 */
519
520enum ftrace_dump_mode {
521 DUMP_NONE,
522 DUMP_ALL,
523 DUMP_ORIG,
524};
525
526#ifdef CONFIG_TRACING
527void tracing_on(void);
528void tracing_off(void);
529int tracing_is_on(void);
530void tracing_snapshot(void);
531void tracing_snapshot_alloc(void);
532
533extern void tracing_start(void);
534extern void tracing_stop(void);
535
536static inline __printf(1, 2)
537void ____trace_printk_check_format(const char *fmt, ...)
538{
539}
540#define __trace_printk_check_format(fmt, args...) \
541do { \
542 if (0) \
543 ____trace_printk_check_format(fmt, ##args); \
544} while (0)
545
546/**
547 * trace_printk - printf formatting in the ftrace buffer
548 * @fmt: the printf format for printing
549 *
550 * Note: __trace_printk is an internal function for trace_printk() and
551 * the @ip is passed in via the trace_printk() macro.
552 *
553 * This function allows a kernel developer to debug fast path sections
554 * that printk is not appropriate for. By scattering in various
555 * printk like tracing in the code, a developer can quickly see
556 * where problems are occurring.
557 *
558 * This is intended as a debugging tool for the developer only.
559 * Please refrain from leaving trace_printks scattered around in
560 * your code. (Extra memory is used for special buffers that are
561 * allocated when trace_printk() is used.)
562 *
563 * A little optimization trick is done here. If there's only one
564 * argument, there's no need to scan the string for printf formats.
565 * The trace_puts() will suffice. But how can we take advantage of
566 * using trace_puts() when trace_printk() has only one argument?
567 * By stringifying the args and checking the size we can tell
568 * whether or not there are args. __stringify((__VA_ARGS__)) will
569 * turn into "()\0" with a size of 3 when there are no args, anything
570 * else will be bigger. All we need to do is define a string to this,
571 * and then take its size and compare to 3. If it's bigger, use
572 * do_trace_printk() otherwise, optimize it to trace_puts(). Then just
573 * let gcc optimize the rest.
574 */
575
576#define trace_printk(fmt, ...) \
577do { \
578 char _______STR[] = __stringify((__VA_ARGS__)); \
579 if (sizeof(_______STR) > 3) \
580 do_trace_printk(fmt, ##__VA_ARGS__); \
581 else \
582 trace_puts(fmt); \
583} while (0)
584
585#define do_trace_printk(fmt, args...) \
586do { \
587 static const char *trace_printk_fmt __used \
588 __section("__trace_printk_fmt") = \
589 __builtin_constant_p(fmt) ? fmt : NULL; \
590 \
591 __trace_printk_check_format(fmt, ##args); \
592 \
593 if (__builtin_constant_p(fmt)) \
594 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \
595 else \
596 __trace_printk(_THIS_IP_, fmt, ##args); \
597} while (0)
598
599extern __printf(2, 3)
600int __trace_bprintk(unsigned long ip, const char *fmt, ...);
601
602extern __printf(2, 3)
603int __trace_printk(unsigned long ip, const char *fmt, ...);
604
605/**
606 * trace_puts - write a string into the ftrace buffer
607 * @str: the string to record
608 *
609 * Note: __trace_bputs is an internal function for trace_puts and
610 * the @ip is passed in via the trace_puts macro.
611 *
612 * This is similar to trace_printk() but is made for those really fast
613 * paths that a developer wants the least amount of "Heisenbug" effects,
614 * where the processing of the print format is still too much.
615 *
616 * This function allows a kernel developer to debug fast path sections
617 * that printk is not appropriate for. By scattering in various
618 * printk like tracing in the code, a developer can quickly see
619 * where problems are occurring.
620 *
621 * This is intended as a debugging tool for the developer only.
622 * Please refrain from leaving trace_puts scattered around in
623 * your code. (Extra memory is used for special buffers that are
624 * allocated when trace_puts() is used.)
625 *
626 * Returns: 0 if nothing was written, positive # if string was.
627 * (1 when __trace_bputs is used, strlen(str) when __trace_puts is used)
628 */
629
630#define trace_puts(str) ({ \
631 static const char *trace_printk_fmt __used \
632 __section("__trace_printk_fmt") = \
633 __builtin_constant_p(str) ? str : NULL; \
634 \
635 if (__builtin_constant_p(str)) \
636 __trace_bputs(_THIS_IP_, trace_printk_fmt); \
637 else \
638 __trace_puts(_THIS_IP_, str, strlen(str)); \
639})
640extern int __trace_bputs(unsigned long ip, const char *str);
641extern int __trace_puts(unsigned long ip, const char *str, int size);
642
643extern void trace_dump_stack(int skip);
644
645/*
646 * The double __builtin_constant_p is because gcc will give us an error
647 * if we try to allocate the static variable to fmt if it is not a
648 * constant. Even with the outer if statement.
649 */
650#define ftrace_vprintk(fmt, vargs) \
651do { \
652 if (__builtin_constant_p(fmt)) { \
653 static const char *trace_printk_fmt __used \
654 __section("__trace_printk_fmt") = \
655 __builtin_constant_p(fmt) ? fmt : NULL; \
656 \
657 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs); \
658 } else \
659 __ftrace_vprintk(_THIS_IP_, fmt, vargs); \
660} while (0)
661
662extern __printf(2, 0) int
663__ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
664
665extern __printf(2, 0) int
666__ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
667
668extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
669#else
670static inline void tracing_start(void) { }
671static inline void tracing_stop(void) { }
672static inline void trace_dump_stack(int skip) { }
673
674static inline void tracing_on(void) { }
675static inline void tracing_off(void) { }
676static inline int tracing_is_on(void) { return 0; }
677static inline void tracing_snapshot(void) { }
678static inline void tracing_snapshot_alloc(void) { }
679
680static inline __printf(1, 2)
681int trace_printk(const char *fmt, ...)
682{
683 return 0;
684}
685static __printf(1, 0) inline int
686ftrace_vprintk(const char *fmt, va_list ap)
687{
688 return 0;
689}
690static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
691#endif /* CONFIG_TRACING */
692
693/* This counts to 12. Any more, it will return 13th argument. */
694#define __COUNT_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _n, X...) _n
695#define COUNT_ARGS(X...) __COUNT_ARGS(, ##X, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
696
697#define __CONCAT(a, b) a ## b
698#define CONCATENATE(a, b) __CONCAT(a, b)
699
700/**
701 * container_of - cast a member of a structure out to the containing structure
702 * @ptr: the pointer to the member.
703 * @type: the type of the container struct this is embedded in.
704 * @member: the name of the member within the struct.
705 *
706 */
707#define container_of(ptr, type, member) ({ \
708 void *__mptr = (void *)(ptr); \
709 BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
710 !__same_type(*(ptr), void), \
711 "pointer type mismatch in container_of()"); \
712 ((type *)(__mptr - offsetof(type, member))); })
713
714/**
715 * container_of_safe - cast a member of a structure out to the containing structure
716 * @ptr: the pointer to the member.
717 * @type: the type of the container struct this is embedded in.
718 * @member: the name of the member within the struct.
719 *
720 * If IS_ERR_OR_NULL(ptr), ptr is returned unchanged.
721 */
722#define container_of_safe(ptr, type, member) ({ \
723 void *__mptr = (void *)(ptr); \
724 BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
725 !__same_type(*(ptr), void), \
726 "pointer type mismatch in container_of()"); \
727 IS_ERR_OR_NULL(__mptr) ? ERR_CAST(__mptr) : \
728 ((type *)(__mptr - offsetof(type, member))); })
729
730/* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
731#ifdef CONFIG_FTRACE_MCOUNT_RECORD
732# define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
733#endif
734
735/* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */
736#define VERIFY_OCTAL_PERMISSIONS(perms) \
737 (BUILD_BUG_ON_ZERO((perms) < 0) + \
738 BUILD_BUG_ON_ZERO((perms) > 0777) + \
739 /* USER_READABLE >= GROUP_READABLE >= OTHER_READABLE */ \
740 BUILD_BUG_ON_ZERO((((perms) >> 6) & 4) < (((perms) >> 3) & 4)) + \
741 BUILD_BUG_ON_ZERO((((perms) >> 3) & 4) < ((perms) & 4)) + \
742 /* USER_WRITABLE >= GROUP_WRITABLE */ \
743 BUILD_BUG_ON_ZERO((((perms) >> 6) & 2) < (((perms) >> 3) & 2)) + \
744 /* OTHER_WRITABLE? Generally considered a bad idea. */ \
745 BUILD_BUG_ON_ZERO((perms) & 2) + \
746 (perms))
747#endif