1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_KERNEL_H
3 #define _LINUX_KERNEL_H
4
5 #include <linux/stdarg.h>
6 #include <linux/align.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/kstrtox.h>
14 #include <linux/log2.h>
15 #include <linux/math.h>
16 #include <linux/minmax.h>
17 #include <linux/typecheck.h>
18 #include <linux/panic.h>
19 #include <linux/printk.h>
20 #include <linux/build_bug.h>
21 #include <linux/static_call_types.h>
22 #include <asm/byteorder.h>
23
24 #include <uapi/linux/kernel.h>
25
26 #define STACK_MAGIC 0xdeadbeef
27
28 /**
29 * REPEAT_BYTE - repeat the value @x multiple times as an unsigned long value
30 * @x: value to repeat
31 *
32 * NOTE: @x is not checked for > 0xff; larger values produce odd results.
33 */
34 #define REPEAT_BYTE(x) ((~0ul / 0xff) * (x))
35
36 /* generic data direction definitions */
37 #define READ 0
38 #define WRITE 1
39
40 /**
41 * ARRAY_SIZE - get the number of elements in array @arr
42 * @arr: array to be sized
43 */
44 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
45
46 #define PTR_IF(cond, ptr) ((cond) ? (ptr) : NULL)
47
48 #define u64_to_user_ptr(x) ( \
49 { \
50 typecheck(u64, (x)); \
51 (void __user *)(uintptr_t)(x); \
52 } \
53 )
54
55 #define typeof_member(T, m) typeof(((T*)0)->m)
56
57 #define _RET_IP_ (unsigned long)__builtin_return_address(0)
58 #define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; })
59
60 /**
61 * upper_32_bits - return bits 32-63 of a number
62 * @n: the number we're accessing
63 *
64 * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress
65 * the "right shift count >= width of type" warning when that quantity is
66 * 32-bits.
67 */
68 #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
69
70 /**
71 * lower_32_bits - return bits 0-31 of a number
72 * @n: the number we're accessing
73 */
74 #define lower_32_bits(n) ((u32)((n) & 0xffffffff))
75
76 /**
77 * upper_16_bits - return bits 16-31 of a number
78 * @n: the number we're accessing
79 */
80 #define upper_16_bits(n) ((u16)((n) >> 16))
81
82 /**
83 * lower_16_bits - return bits 0-15 of a number
84 * @n: the number we're accessing
85 */
86 #define lower_16_bits(n) ((u16)((n) & 0xffff))
87
88 struct completion;
89 struct user;
90
91 #ifdef CONFIG_PREEMPT_VOLUNTARY
92
93 extern int __cond_resched(void);
94 # define might_resched() __cond_resched()
95
96 #elif defined(CONFIG_PREEMPT_DYNAMIC)
97
98 extern int __cond_resched(void);
99
100 DECLARE_STATIC_CALL(might_resched, __cond_resched);
101
might_resched(void)102 static __always_inline void might_resched(void)
103 {
104 static_call_mod(might_resched)();
105 }
106
107 #else
108
109 # define might_resched() do { } while (0)
110
111 #endif /* CONFIG_PREEMPT_* */
112
113 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
114 extern void ___might_sleep(const char *file, int line, int preempt_offset);
115 extern void __might_sleep(const char *file, int line, int preempt_offset);
116 extern void __cant_sleep(const char *file, int line, int preempt_offset);
117 extern void __cant_migrate(const char *file, int line);
118
119 /**
120 * might_sleep - annotation for functions that can sleep
121 *
122 * this macro will print a stack trace if it is executed in an atomic
123 * context (spinlock, irq-handler, ...). Additional sections where blocking is
124 * not allowed can be annotated with non_block_start() and non_block_end()
125 * pairs.
126 *
127 * This is a useful debugging help to be able to catch problems early and not
128 * be bitten later when the calling function happens to sleep when it is not
129 * supposed to.
130 */
131 # define might_sleep() \
132 do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
133 /**
134 * cant_sleep - annotation for functions that cannot sleep
135 *
136 * this macro will print a stack trace if it is executed with preemption enabled
137 */
138 # define cant_sleep() \
139 do { __cant_sleep(__FILE__, __LINE__, 0); } while (0)
140 # define sched_annotate_sleep() (current->task_state_change = 0)
141
142 /**
143 * cant_migrate - annotation for functions that cannot migrate
144 *
145 * Will print a stack trace if executed in code which is migratable
146 */
147 # define cant_migrate() \
148 do { \
149 if (IS_ENABLED(CONFIG_SMP)) \
150 __cant_migrate(__FILE__, __LINE__); \
151 } while (0)
152
153 /**
154 * non_block_start - annotate the start of section where sleeping is prohibited
155 *
156 * This is on behalf of the oom reaper, specifically when it is calling the mmu
157 * notifiers. The problem is that if the notifier were to block on, for example,
158 * mutex_lock() and if the process which holds that mutex were to perform a
159 * sleeping memory allocation, the oom reaper is now blocked on completion of
160 * that memory allocation. Other blocking calls like wait_event() pose similar
161 * issues.
162 */
163 # define non_block_start() (current->non_block_count++)
164 /**
165 * non_block_end - annotate the end of section where sleeping is prohibited
166 *
167 * Closes a section opened by non_block_start().
168 */
169 # define non_block_end() WARN_ON(current->non_block_count-- == 0)
170 #else
___might_sleep(const char * file,int line,int preempt_offset)171 static inline void ___might_sleep(const char *file, int line,
172 int preempt_offset) { }
__might_sleep(const char * file,int line,int preempt_offset)173 static inline void __might_sleep(const char *file, int line,
174 int preempt_offset) { }
175 # define might_sleep() do { might_resched(); } while (0)
176 # define cant_sleep() do { } while (0)
177 # define cant_migrate() do { } while (0)
178 # define sched_annotate_sleep() do { } while (0)
179 # define non_block_start() do { } while (0)
180 # define non_block_end() do { } while (0)
181 #endif
182
183 #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
184
185 #if defined(CONFIG_MMU) && \
186 (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP))
187 #define might_fault() __might_fault(__FILE__, __LINE__)
188 void __might_fault(const char *file, int line);
189 #else
might_fault(void)190 static inline void might_fault(void) { }
191 #endif
192
193 void do_exit(long error_code) __noreturn;
194 void complete_and_exit(struct completion *, long) __noreturn;
195
196 extern int num_to_str(char *buf, int size,
197 unsigned long long num, unsigned int width);
198
199 /* lib/printf utilities */
200
201 extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
202 extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
203 extern __printf(3, 4)
204 int snprintf(char *buf, size_t size, const char *fmt, ...);
205 extern __printf(3, 0)
206 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
207 extern __printf(3, 4)
208 int scnprintf(char *buf, size_t size, const char *fmt, ...);
209 extern __printf(3, 0)
210 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
211 extern __printf(2, 3) __malloc
212 char *kasprintf(gfp_t gfp, const char *fmt, ...);
213 extern __printf(2, 0) __malloc
214 char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
215 extern __printf(2, 0)
216 const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list args);
217
218 extern __scanf(2, 3)
219 int sscanf(const char *, const char *, ...);
220 extern __scanf(2, 0)
221 int vsscanf(const char *, const char *, va_list);
222
223 extern int no_hash_pointers_enable(char *str);
224
225 extern int get_option(char **str, int *pint);
226 extern char *get_options(const char *str, int nints, int *ints);
227 extern unsigned long long memparse(const char *ptr, char **retptr);
228 extern bool parse_option_str(const char *str, const char *option);
229 extern char *next_arg(char *args, char **param, char **val);
230
231 extern int core_kernel_text(unsigned long addr);
232 extern int init_kernel_text(unsigned long addr);
233 extern int core_kernel_data(unsigned long addr);
234 extern int __kernel_text_address(unsigned long addr);
235 extern int kernel_text_address(unsigned long addr);
236 extern int func_ptr_is_kernel_text(void *ptr);
237
238 extern void bust_spinlocks(int yes);
239
240 extern int root_mountflags;
241
242 extern bool early_boot_irqs_disabled;
243
244 /*
245 * Values used for system_state. Ordering of the states must not be changed
246 * as code checks for <, <=, >, >= STATE.
247 */
248 extern enum system_states {
249 SYSTEM_BOOTING,
250 SYSTEM_SCHEDULING,
251 SYSTEM_RUNNING,
252 SYSTEM_HALT,
253 SYSTEM_POWER_OFF,
254 SYSTEM_RESTART,
255 SYSTEM_SUSPEND,
256 } system_state;
257
258 extern const char hex_asc[];
259 #define hex_asc_lo(x) hex_asc[((x) & 0x0f)]
260 #define hex_asc_hi(x) hex_asc[((x) & 0xf0) >> 4]
261
hex_byte_pack(char * buf,u8 byte)262 static inline char *hex_byte_pack(char *buf, u8 byte)
263 {
264 *buf++ = hex_asc_hi(byte);
265 *buf++ = hex_asc_lo(byte);
266 return buf;
267 }
268
269 extern const char hex_asc_upper[];
270 #define hex_asc_upper_lo(x) hex_asc_upper[((x) & 0x0f)]
271 #define hex_asc_upper_hi(x) hex_asc_upper[((x) & 0xf0) >> 4]
272
hex_byte_pack_upper(char * buf,u8 byte)273 static inline char *hex_byte_pack_upper(char *buf, u8 byte)
274 {
275 *buf++ = hex_asc_upper_hi(byte);
276 *buf++ = hex_asc_upper_lo(byte);
277 return buf;
278 }
279
280 extern int hex_to_bin(char ch);
281 extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
282 extern char *bin2hex(char *dst, const void *src, size_t count);
283
284 bool mac_pton(const char *s, u8 *mac);
285
286 /*
287 * General tracing related utility functions - trace_printk(),
288 * tracing_on/tracing_off and tracing_start()/tracing_stop
289 *
290 * Use tracing_on/tracing_off when you want to quickly turn on or off
291 * tracing. It simply enables or disables the recording of the trace events.
292 * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
293 * file, which gives a means for the kernel and userspace to interact.
294 * Place a tracing_off() in the kernel where you want tracing to end.
295 * From user space, examine the trace, and then echo 1 > tracing_on
296 * to continue tracing.
297 *
298 * tracing_stop/tracing_start has slightly more overhead. It is used
299 * by things like suspend to ram where disabling the recording of the
300 * trace is not enough, but tracing must actually stop because things
301 * like calling smp_processor_id() may crash the system.
302 *
303 * Most likely, you want to use tracing_on/tracing_off.
304 */
305
306 enum ftrace_dump_mode {
307 DUMP_NONE,
308 DUMP_ALL,
309 DUMP_ORIG,
310 };
311
312 #ifdef CONFIG_TRACING
313 void tracing_on(void);
314 void tracing_off(void);
315 int tracing_is_on(void);
316 void tracing_snapshot(void);
317 void tracing_snapshot_alloc(void);
318
319 extern void tracing_start(void);
320 extern void tracing_stop(void);
321
322 static inline __printf(1, 2)
____trace_printk_check_format(const char * fmt,...)323 void ____trace_printk_check_format(const char *fmt, ...)
324 {
325 }
326 #define __trace_printk_check_format(fmt, args...) \
327 do { \
328 if (0) \
329 ____trace_printk_check_format(fmt, ##args); \
330 } while (0)
331
332 /**
333 * trace_printk - printf formatting in the ftrace buffer
334 * @fmt: the printf format for printing
335 *
336 * Note: __trace_printk is an internal function for trace_printk() and
337 * the @ip is passed in via the trace_printk() macro.
338 *
339 * This function allows a kernel developer to debug fast path sections
340 * that printk is not appropriate for. By scattering in various
341 * printk like tracing in the code, a developer can quickly see
342 * where problems are occurring.
343 *
344 * This is intended as a debugging tool for the developer only.
345 * Please refrain from leaving trace_printks scattered around in
346 * your code. (Extra memory is used for special buffers that are
347 * allocated when trace_printk() is used.)
348 *
349 * A little optimization trick is done here. If there's only one
350 * argument, there's no need to scan the string for printf formats.
351 * The trace_puts() will suffice. But how can we take advantage of
352 * using trace_puts() when trace_printk() has only one argument?
353 * By stringifying the args and checking the size we can tell
354 * whether or not there are args. __stringify((__VA_ARGS__)) will
355 * turn into "()\0" with a size of 3 when there are no args, anything
356 * else will be bigger. All we need to do is define a string to this,
357 * and then take its size and compare to 3. If it's bigger, use
358 * do_trace_printk() otherwise, optimize it to trace_puts(). Then just
359 * let gcc optimize the rest.
360 */
361
362 #define trace_printk(fmt, ...) \
363 do { \
364 char _______STR[] = __stringify((__VA_ARGS__)); \
365 if (sizeof(_______STR) > 3) \
366 do_trace_printk(fmt, ##__VA_ARGS__); \
367 else \
368 trace_puts(fmt); \
369 } while (0)
370
371 #define do_trace_printk(fmt, args...) \
372 do { \
373 static const char *trace_printk_fmt __used \
374 __section("__trace_printk_fmt") = \
375 __builtin_constant_p(fmt) ? fmt : NULL; \
376 \
377 __trace_printk_check_format(fmt, ##args); \
378 \
379 if (__builtin_constant_p(fmt)) \
380 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \
381 else \
382 __trace_printk(_THIS_IP_, fmt, ##args); \
383 } while (0)
384
385 extern __printf(2, 3)
386 int __trace_bprintk(unsigned long ip, const char *fmt, ...);
387
388 extern __printf(2, 3)
389 int __trace_printk(unsigned long ip, const char *fmt, ...);
390
391 /**
392 * trace_puts - write a string into the ftrace buffer
393 * @str: the string to record
394 *
395 * Note: __trace_bputs is an internal function for trace_puts and
396 * the @ip is passed in via the trace_puts macro.
397 *
398 * This is similar to trace_printk() but is made for those really fast
399 * paths that a developer wants the least amount of "Heisenbug" effects,
400 * where the processing of the print format is still too much.
401 *
402 * This function allows a kernel developer to debug fast path sections
403 * that printk is not appropriate for. By scattering in various
404 * printk like tracing in the code, a developer can quickly see
405 * where problems are occurring.
406 *
407 * This is intended as a debugging tool for the developer only.
408 * Please refrain from leaving trace_puts scattered around in
409 * your code. (Extra memory is used for special buffers that are
410 * allocated when trace_puts() is used.)
411 *
412 * Returns: 0 if nothing was written, positive # if string was.
413 * (1 when __trace_bputs is used, strlen(str) when __trace_puts is used)
414 */
415
416 #define trace_puts(str) ({ \
417 static const char *trace_printk_fmt __used \
418 __section("__trace_printk_fmt") = \
419 __builtin_constant_p(str) ? str : NULL; \
420 \
421 if (__builtin_constant_p(str)) \
422 __trace_bputs(_THIS_IP_, trace_printk_fmt); \
423 else \
424 __trace_puts(_THIS_IP_, str, strlen(str)); \
425 })
426 extern int __trace_bputs(unsigned long ip, const char *str);
427 extern int __trace_puts(unsigned long ip, const char *str, int size);
428
429 extern void trace_dump_stack(int skip);
430
431 /*
432 * The double __builtin_constant_p is because gcc will give us an error
433 * if we try to allocate the static variable to fmt if it is not a
434 * constant. Even with the outer if statement.
435 */
436 #define ftrace_vprintk(fmt, vargs) \
437 do { \
438 if (__builtin_constant_p(fmt)) { \
439 static const char *trace_printk_fmt __used \
440 __section("__trace_printk_fmt") = \
441 __builtin_constant_p(fmt) ? fmt : NULL; \
442 \
443 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs); \
444 } else \
445 __ftrace_vprintk(_THIS_IP_, fmt, vargs); \
446 } while (0)
447
448 extern __printf(2, 0) int
449 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
450
451 extern __printf(2, 0) int
452 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
453
454 extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
455 #else
tracing_start(void)456 static inline void tracing_start(void) { }
tracing_stop(void)457 static inline void tracing_stop(void) { }
trace_dump_stack(int skip)458 static inline void trace_dump_stack(int skip) { }
459
tracing_on(void)460 static inline void tracing_on(void) { }
tracing_off(void)461 static inline void tracing_off(void) { }
tracing_is_on(void)462 static inline int tracing_is_on(void) { return 0; }
tracing_snapshot(void)463 static inline void tracing_snapshot(void) { }
tracing_snapshot_alloc(void)464 static inline void tracing_snapshot_alloc(void) { }
465
466 static inline __printf(1, 2)
trace_printk(const char * fmt,...)467 int trace_printk(const char *fmt, ...)
468 {
469 return 0;
470 }
471 static __printf(1, 0) inline int
ftrace_vprintk(const char * fmt,va_list ap)472 ftrace_vprintk(const char *fmt, va_list ap)
473 {
474 return 0;
475 }
ftrace_dump(enum ftrace_dump_mode oops_dump_mode)476 static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
477 #endif /* CONFIG_TRACING */
478
479 /* This counts to 12. Any more, it will return 13th argument. */
480 #define __COUNT_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _n, X...) _n
481 #define COUNT_ARGS(X...) __COUNT_ARGS(, ##X, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
482
483 #define __CONCAT(a, b) a ## b
484 #define CONCATENATE(a, b) __CONCAT(a, b)
485
486 /**
487 * container_of - cast a member of a structure out to the containing structure
488 * @ptr: the pointer to the member.
489 * @type: the type of the container struct this is embedded in.
490 * @member: the name of the member within the struct.
491 *
492 */
493 #define container_of(ptr, type, member) ({ \
494 void *__mptr = (void *)(ptr); \
495 BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
496 !__same_type(*(ptr), void), \
497 "pointer type mismatch in container_of()"); \
498 ((type *)(__mptr - offsetof(type, member))); })
499
500 /**
501 * container_of_safe - cast a member of a structure out to the containing structure
502 * @ptr: the pointer to the member.
503 * @type: the type of the container struct this is embedded in.
504 * @member: the name of the member within the struct.
505 *
506 * If IS_ERR_OR_NULL(ptr), ptr is returned unchanged.
507 */
508 #define container_of_safe(ptr, type, member) ({ \
509 void *__mptr = (void *)(ptr); \
510 BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
511 !__same_type(*(ptr), void), \
512 "pointer type mismatch in container_of()"); \
513 IS_ERR_OR_NULL(__mptr) ? ERR_CAST(__mptr) : \
514 ((type *)(__mptr - offsetof(type, member))); })
515
516 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
517 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
518 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
519 #endif
520
521 /* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */
522 #define VERIFY_OCTAL_PERMISSIONS(perms) \
523 (BUILD_BUG_ON_ZERO((perms) < 0) + \
524 BUILD_BUG_ON_ZERO((perms) > 0777) + \
525 /* USER_READABLE >= GROUP_READABLE >= OTHER_READABLE */ \
526 BUILD_BUG_ON_ZERO((((perms) >> 6) & 4) < (((perms) >> 3) & 4)) + \
527 BUILD_BUG_ON_ZERO((((perms) >> 3) & 4) < ((perms) & 4)) + \
528 /* USER_WRITABLE >= GROUP_WRITABLE */ \
529 BUILD_BUG_ON_ZERO((((perms) >> 6) & 2) < (((perms) >> 3) & 2)) + \
530 /* OTHER_WRITABLE? Generally considered a bad idea. */ \
531 BUILD_BUG_ON_ZERO((perms) & 2) + \
532 (perms))
533 #endif
534
