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