Line data Source code
1 : /* SPDX-License-Identifier: GPL-2.0 */
2 : /*
3 : * NOTE:
4 : *
5 : * This header has combined a lot of unrelated to each other stuff.
6 : * The process of splitting its content is in progress while keeping
7 : * backward compatibility. That's why it's highly recommended NOT to
8 : * include this header inside another header file, especially under
9 : * generic or architectural include/ directory.
10 : */
11 : #ifndef _LINUX_KERNEL_H
12 : #define _LINUX_KERNEL_H
13 :
14 : #include <linux/stdarg.h>
15 : #include <linux/align.h>
16 : #include <linux/limits.h>
17 : #include <linux/linkage.h>
18 : #include <linux/stddef.h>
19 : #include <linux/types.h>
20 : #include <linux/compiler.h>
21 : #include <linux/container_of.h>
22 : #include <linux/bitops.h>
23 : #include <linux/hex.h>
24 : #include <linux/kstrtox.h>
25 : #include <linux/log2.h>
26 : #include <linux/math.h>
27 : #include <linux/minmax.h>
28 : #include <linux/typecheck.h>
29 : #include <linux/panic.h>
30 : #include <linux/printk.h>
31 : #include <linux/build_bug.h>
32 : #include <linux/static_call_types.h>
33 : #include <linux/instruction_pointer.h>
34 : #include <asm/byteorder.h>
35 :
36 : #include <uapi/linux/kernel.h>
37 :
38 : #define STACK_MAGIC 0xdeadbeef
39 :
40 : /**
41 : * REPEAT_BYTE - repeat the value @x multiple times as an unsigned long value
42 : * @x: value to repeat
43 : *
44 : * NOTE: @x is not checked for > 0xff; larger values produce odd results.
45 : */
46 : #define REPEAT_BYTE(x) ((~0ul / 0xff) * (x))
47 :
48 : /* generic data direction definitions */
49 : #define READ 0
50 : #define WRITE 1
51 :
52 : /**
53 : * ARRAY_SIZE - get the number of elements in array @arr
54 : * @arr: array to be sized
55 : */
56 : #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
57 :
58 : #define PTR_IF(cond, ptr) ((cond) ? (ptr) : NULL)
59 :
60 : #define u64_to_user_ptr(x) ( \
61 : { \
62 : typecheck(u64, (x)); \
63 : (void __user *)(uintptr_t)(x); \
64 : } \
65 : )
66 :
67 : /**
68 : * upper_32_bits - return bits 32-63 of a number
69 : * @n: the number we're accessing
70 : *
71 : * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress
72 : * the "right shift count >= width of type" warning when that quantity is
73 : * 32-bits.
74 : */
75 : #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
76 :
77 : /**
78 : * lower_32_bits - return bits 0-31 of a number
79 : * @n: the number we're accessing
80 : */
81 : #define lower_32_bits(n) ((u32)((n) & 0xffffffff))
82 :
83 : /**
84 : * upper_16_bits - return bits 16-31 of a number
85 : * @n: the number we're accessing
86 : */
87 : #define upper_16_bits(n) ((u16)((n) >> 16))
88 :
89 : /**
90 : * lower_16_bits - return bits 0-15 of a number
91 : * @n: the number we're accessing
92 : */
93 : #define lower_16_bits(n) ((u16)((n) & 0xffff))
94 :
95 : struct completion;
96 : struct user;
97 :
98 : #ifdef CONFIG_PREEMPT_VOLUNTARY_BUILD
99 :
100 : extern int __cond_resched(void);
101 : # define might_resched() __cond_resched()
102 :
103 : #elif defined(CONFIG_PREEMPT_DYNAMIC) && defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL)
104 :
105 : extern int __cond_resched(void);
106 :
107 : DECLARE_STATIC_CALL(might_resched, __cond_resched);
108 :
109 : static __always_inline void might_resched(void)
110 : {
111 25685064309 : static_call_mod(might_resched)();
112 10576848 : }
113 :
114 : #elif defined(CONFIG_PREEMPT_DYNAMIC) && defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY)
115 :
116 : extern int dynamic_might_resched(void);
117 : # define might_resched() dynamic_might_resched()
118 :
119 : #else
120 :
121 : # define might_resched() do { } while (0)
122 :
123 : #endif /* CONFIG_PREEMPT_* */
124 :
125 : #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
126 : extern void __might_resched(const char *file, int line, unsigned int offsets);
127 : extern void __might_sleep(const char *file, int line);
128 : extern void __cant_sleep(const char *file, int line, int preempt_offset);
129 : extern void __cant_migrate(const char *file, int line);
130 :
131 : /**
132 : * might_sleep - annotation for functions that can sleep
133 : *
134 : * this macro will print a stack trace if it is executed in an atomic
135 : * context (spinlock, irq-handler, ...). Additional sections where blocking is
136 : * not allowed can be annotated with non_block_start() and non_block_end()
137 : * pairs.
138 : *
139 : * This is a useful debugging help to be able to catch problems early and not
140 : * be bitten later when the calling function happens to sleep when it is not
141 : * supposed to.
142 : */
143 : # define might_sleep() \
144 : do { __might_sleep(__FILE__, __LINE__); might_resched(); } while (0)
145 : /**
146 : * cant_sleep - annotation for functions that cannot sleep
147 : *
148 : * this macro will print a stack trace if it is executed with preemption enabled
149 : */
150 : # define cant_sleep() \
151 : do { __cant_sleep(__FILE__, __LINE__, 0); } while (0)
152 : # define sched_annotate_sleep() (current->task_state_change = 0)
153 :
154 : /**
155 : * cant_migrate - annotation for functions that cannot migrate
156 : *
157 : * Will print a stack trace if executed in code which is migratable
158 : */
159 : # define cant_migrate() \
160 : do { \
161 : if (IS_ENABLED(CONFIG_SMP)) \
162 : __cant_migrate(__FILE__, __LINE__); \
163 : } while (0)
164 :
165 : /**
166 : * non_block_start - annotate the start of section where sleeping is prohibited
167 : *
168 : * This is on behalf of the oom reaper, specifically when it is calling the mmu
169 : * notifiers. The problem is that if the notifier were to block on, for example,
170 : * mutex_lock() and if the process which holds that mutex were to perform a
171 : * sleeping memory allocation, the oom reaper is now blocked on completion of
172 : * that memory allocation. Other blocking calls like wait_event() pose similar
173 : * issues.
174 : */
175 : # define non_block_start() (current->non_block_count++)
176 : /**
177 : * non_block_end - annotate the end of section where sleeping is prohibited
178 : *
179 : * Closes a section opened by non_block_start().
180 : */
181 : # define non_block_end() WARN_ON(current->non_block_count-- == 0)
182 : #else
183 : static inline void __might_resched(const char *file, int line,
184 : unsigned int offsets) { }
185 : static inline void __might_sleep(const char *file, int line) { }
186 : # define might_sleep() do { might_resched(); } while (0)
187 : # define cant_sleep() do { } while (0)
188 : # define cant_migrate() do { } while (0)
189 : # define sched_annotate_sleep() do { } while (0)
190 : # define non_block_start() do { } while (0)
191 : # define non_block_end() do { } while (0)
192 : #endif
193 :
194 : #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
195 :
196 : #if defined(CONFIG_MMU) && \
197 : (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP))
198 : #define might_fault() __might_fault(__FILE__, __LINE__)
199 : void __might_fault(const char *file, int line);
200 : #else
201 : static inline void might_fault(void) { }
202 : #endif
203 :
204 : void do_exit(long error_code) __noreturn;
205 :
206 : extern int num_to_str(char *buf, int size,
207 : unsigned long long num, unsigned int width);
208 :
209 : /* lib/printf utilities */
210 :
211 : extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
212 : extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
213 : extern __printf(3, 4)
214 : int snprintf(char *buf, size_t size, const char *fmt, ...);
215 : extern __printf(3, 0)
216 : int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
217 : extern __printf(3, 4)
218 : int scnprintf(char *buf, size_t size, const char *fmt, ...);
219 : extern __printf(3, 0)
220 : int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
221 : extern __printf(2, 3) __malloc
222 : char *kasprintf(gfp_t gfp, const char *fmt, ...);
223 : extern __printf(2, 0) __malloc
224 : char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
225 : extern __printf(2, 0)
226 : const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list args);
227 :
228 : extern __scanf(2, 3)
229 : int sscanf(const char *, const char *, ...);
230 : extern __scanf(2, 0)
231 : int vsscanf(const char *, const char *, va_list);
232 :
233 : extern int no_hash_pointers_enable(char *str);
234 :
235 : extern int get_option(char **str, int *pint);
236 : extern char *get_options(const char *str, int nints, int *ints);
237 : extern unsigned long long memparse(const char *ptr, char **retptr);
238 : extern bool parse_option_str(const char *str, const char *option);
239 : extern char *next_arg(char *args, char **param, char **val);
240 :
241 : extern int core_kernel_text(unsigned long addr);
242 : extern int __kernel_text_address(unsigned long addr);
243 : extern int kernel_text_address(unsigned long addr);
244 : extern int func_ptr_is_kernel_text(void *ptr);
245 :
246 : extern void bust_spinlocks(int yes);
247 :
248 : extern int root_mountflags;
249 :
250 : extern bool early_boot_irqs_disabled;
251 :
252 : /*
253 : * Values used for system_state. Ordering of the states must not be changed
254 : * as code checks for <, <=, >, >= STATE.
255 : */
256 : extern enum system_states {
257 : SYSTEM_BOOTING,
258 : SYSTEM_SCHEDULING,
259 : SYSTEM_FREEING_INITMEM,
260 : SYSTEM_RUNNING,
261 : SYSTEM_HALT,
262 : SYSTEM_POWER_OFF,
263 : SYSTEM_RESTART,
264 : SYSTEM_SUSPEND,
265 : } system_state;
266 :
267 : /*
268 : * General tracing related utility functions - trace_printk(),
269 : * tracing_on/tracing_off and tracing_start()/tracing_stop
270 : *
271 : * Use tracing_on/tracing_off when you want to quickly turn on or off
272 : * tracing. It simply enables or disables the recording of the trace events.
273 : * This also corresponds to the user space /sys/kernel/tracing/tracing_on
274 : * file, which gives a means for the kernel and userspace to interact.
275 : * Place a tracing_off() in the kernel where you want tracing to end.
276 : * From user space, examine the trace, and then echo 1 > tracing_on
277 : * to continue tracing.
278 : *
279 : * tracing_stop/tracing_start has slightly more overhead. It is used
280 : * by things like suspend to ram where disabling the recording of the
281 : * trace is not enough, but tracing must actually stop because things
282 : * like calling smp_processor_id() may crash the system.
283 : *
284 : * Most likely, you want to use tracing_on/tracing_off.
285 : */
286 :
287 : enum ftrace_dump_mode {
288 : DUMP_NONE,
289 : DUMP_ALL,
290 : DUMP_ORIG,
291 : };
292 :
293 : #ifdef CONFIG_TRACING
294 : void tracing_on(void);
295 : void tracing_off(void);
296 : int tracing_is_on(void);
297 : void tracing_snapshot(void);
298 : void tracing_snapshot_alloc(void);
299 :
300 : extern void tracing_start(void);
301 : extern void tracing_stop(void);
302 :
303 : static inline __printf(1, 2)
304 : void ____trace_printk_check_format(const char *fmt, ...)
305 : {
306 : }
307 : #define __trace_printk_check_format(fmt, args...) \
308 : do { \
309 : if (0) \
310 : ____trace_printk_check_format(fmt, ##args); \
311 : } while (0)
312 :
313 : /**
314 : * trace_printk - printf formatting in the ftrace buffer
315 : * @fmt: the printf format for printing
316 : *
317 : * Note: __trace_printk is an internal function for trace_printk() and
318 : * the @ip is passed in via the trace_printk() macro.
319 : *
320 : * This function allows a kernel developer to debug fast path sections
321 : * that printk is not appropriate for. By scattering in various
322 : * printk like tracing in the code, a developer can quickly see
323 : * where problems are occurring.
324 : *
325 : * This is intended as a debugging tool for the developer only.
326 : * Please refrain from leaving trace_printks scattered around in
327 : * your code. (Extra memory is used for special buffers that are
328 : * allocated when trace_printk() is used.)
329 : *
330 : * A little optimization trick is done here. If there's only one
331 : * argument, there's no need to scan the string for printf formats.
332 : * The trace_puts() will suffice. But how can we take advantage of
333 : * using trace_puts() when trace_printk() has only one argument?
334 : * By stringifying the args and checking the size we can tell
335 : * whether or not there are args. __stringify((__VA_ARGS__)) will
336 : * turn into "()\0" with a size of 3 when there are no args, anything
337 : * else will be bigger. All we need to do is define a string to this,
338 : * and then take its size and compare to 3. If it's bigger, use
339 : * do_trace_printk() otherwise, optimize it to trace_puts(). Then just
340 : * let gcc optimize the rest.
341 : */
342 :
343 : #define trace_printk(fmt, ...) \
344 : do { \
345 : char _______STR[] = __stringify((__VA_ARGS__)); \
346 : if (sizeof(_______STR) > 3) \
347 : do_trace_printk(fmt, ##__VA_ARGS__); \
348 : else \
349 : trace_puts(fmt); \
350 : } while (0)
351 :
352 : #define do_trace_printk(fmt, args...) \
353 : do { \
354 : static const char *trace_printk_fmt __used \
355 : __section("__trace_printk_fmt") = \
356 : __builtin_constant_p(fmt) ? fmt : NULL; \
357 : \
358 : __trace_printk_check_format(fmt, ##args); \
359 : \
360 : if (__builtin_constant_p(fmt)) \
361 : __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \
362 : else \
363 : __trace_printk(_THIS_IP_, fmt, ##args); \
364 : } while (0)
365 :
366 : extern __printf(2, 3)
367 : int __trace_bprintk(unsigned long ip, const char *fmt, ...);
368 :
369 : extern __printf(2, 3)
370 : int __trace_printk(unsigned long ip, const char *fmt, ...);
371 :
372 : /**
373 : * trace_puts - write a string into the ftrace buffer
374 : * @str: the string to record
375 : *
376 : * Note: __trace_bputs is an internal function for trace_puts and
377 : * the @ip is passed in via the trace_puts macro.
378 : *
379 : * This is similar to trace_printk() but is made for those really fast
380 : * paths that a developer wants the least amount of "Heisenbug" effects,
381 : * where the processing of the print format is still too much.
382 : *
383 : * This function allows a kernel developer to debug fast path sections
384 : * that printk is not appropriate for. By scattering in various
385 : * printk like tracing in the code, a developer can quickly see
386 : * where problems are occurring.
387 : *
388 : * This is intended as a debugging tool for the developer only.
389 : * Please refrain from leaving trace_puts scattered around in
390 : * your code. (Extra memory is used for special buffers that are
391 : * allocated when trace_puts() is used.)
392 : *
393 : * Returns: 0 if nothing was written, positive # if string was.
394 : * (1 when __trace_bputs is used, strlen(str) when __trace_puts is used)
395 : */
396 :
397 : #define trace_puts(str) ({ \
398 : static const char *trace_printk_fmt __used \
399 : __section("__trace_printk_fmt") = \
400 : __builtin_constant_p(str) ? str : NULL; \
401 : \
402 : if (__builtin_constant_p(str)) \
403 : __trace_bputs(_THIS_IP_, trace_printk_fmt); \
404 : else \
405 : __trace_puts(_THIS_IP_, str, strlen(str)); \
406 : })
407 : extern int __trace_bputs(unsigned long ip, const char *str);
408 : extern int __trace_puts(unsigned long ip, const char *str, int size);
409 :
410 : extern void trace_dump_stack(int skip);
411 :
412 : /*
413 : * The double __builtin_constant_p is because gcc will give us an error
414 : * if we try to allocate the static variable to fmt if it is not a
415 : * constant. Even with the outer if statement.
416 : */
417 : #define ftrace_vprintk(fmt, vargs) \
418 : do { \
419 : if (__builtin_constant_p(fmt)) { \
420 : static const char *trace_printk_fmt __used \
421 : __section("__trace_printk_fmt") = \
422 : __builtin_constant_p(fmt) ? fmt : NULL; \
423 : \
424 : __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs); \
425 : } else \
426 : __ftrace_vprintk(_THIS_IP_, fmt, vargs); \
427 : } while (0)
428 :
429 : extern __printf(2, 0) int
430 : __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
431 :
432 : extern __printf(2, 0) int
433 : __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
434 :
435 : extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
436 : #else
437 : static inline void tracing_start(void) { }
438 : static inline void tracing_stop(void) { }
439 : static inline void trace_dump_stack(int skip) { }
440 :
441 : static inline void tracing_on(void) { }
442 : static inline void tracing_off(void) { }
443 : static inline int tracing_is_on(void) { return 0; }
444 : static inline void tracing_snapshot(void) { }
445 : static inline void tracing_snapshot_alloc(void) { }
446 :
447 : static inline __printf(1, 2)
448 : int trace_printk(const char *fmt, ...)
449 : {
450 : return 0;
451 : }
452 : static __printf(1, 0) inline int
453 : ftrace_vprintk(const char *fmt, va_list ap)
454 : {
455 : return 0;
456 : }
457 : static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
458 : #endif /* CONFIG_TRACING */
459 :
460 : /* This counts to 12. Any more, it will return 13th argument. */
461 : #define __COUNT_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _n, X...) _n
462 : #define COUNT_ARGS(X...) __COUNT_ARGS(, ##X, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
463 :
464 : #define __CONCAT(a, b) a ## b
465 : #define CONCATENATE(a, b) __CONCAT(a, b)
466 :
467 : /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
468 : #ifdef CONFIG_FTRACE_MCOUNT_RECORD
469 : # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
470 : #endif
471 :
472 : /* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */
473 : #define VERIFY_OCTAL_PERMISSIONS(perms) \
474 : (BUILD_BUG_ON_ZERO((perms) < 0) + \
475 : BUILD_BUG_ON_ZERO((perms) > 0777) + \
476 : /* USER_READABLE >= GROUP_READABLE >= OTHER_READABLE */ \
477 : BUILD_BUG_ON_ZERO((((perms) >> 6) & 4) < (((perms) >> 3) & 4)) + \
478 : BUILD_BUG_ON_ZERO((((perms) >> 3) & 4) < ((perms) & 4)) + \
479 : /* USER_WRITABLE >= GROUP_WRITABLE */ \
480 : BUILD_BUG_ON_ZERO((((perms) >> 6) & 2) < (((perms) >> 3) & 2)) + \
481 : /* OTHER_WRITABLE? Generally considered a bad idea. */ \
482 : BUILD_BUG_ON_ZERO((perms) & 2) + \
483 : (perms))
484 : #endif
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