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