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/array_size.h>
17 #include <linux/limits.h>
18 #include <linux/linkage.h>
19 #include <linux/stddef.h>
20 #include <linux/types.h>
21 #include <linux/compiler.h>
22 #include <linux/container_of.h>
23 #include <linux/bitops.h>
24 #include <linux/hex.h>
25 #include <linux/kstrtox.h>
26 #include <linux/log2.h>
27 #include <linux/math.h>
28 #include <linux/minmax.h>
29 #include <linux/typecheck.h>
30 #include <linux/panic.h>
31 #include <linux/printk.h>
32 #include <linux/build_bug.h>
33 #include <linux/sprintf.h>
34 #include <linux/static_call_types.h>
35 #include <linux/instruction_pointer.h>
36 #include <linux/wordpart.h>
37
38 #include <asm/byteorder.h>
39
40 #include <uapi/linux/kernel.h>
41
42 #define STACK_MAGIC 0xdeadbeef
43
44 /* generic data direction definitions */
45 #define READ 0
46 #define WRITE 1
47
48 #define PTR_IF(cond, ptr) ((cond) ? (ptr) : NULL)
49
50 #define u64_to_user_ptr(x) ( \
51 { \
52 typecheck(u64, (x)); \
53 (void __user *)(uintptr_t)(x); \
54 } \
55 )
56
57 struct completion;
58 struct user;
59
60 #ifdef CONFIG_PREEMPT_VOLUNTARY_BUILD
61
62 extern int __cond_resched(void);
63 # define might_resched() __cond_resched()
64
65 #elif defined(CONFIG_PREEMPT_DYNAMIC) && defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL)
66
67 extern int __cond_resched(void);
68
69 DECLARE_STATIC_CALL(might_resched, __cond_resched);
70
might_resched(void)71 static __always_inline void might_resched(void)
72 {
73 static_call_mod(might_resched)();
74 }
75
76 #elif defined(CONFIG_PREEMPT_DYNAMIC) && defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY)
77
78 extern int dynamic_might_resched(void);
79 # define might_resched() dynamic_might_resched()
80
81 #else
82
83 # define might_resched() do { } while (0)
84
85 #endif /* CONFIG_PREEMPT_* */
86
87 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
88 extern void __might_resched(const char *file, int line, unsigned int offsets);
89 extern void __might_sleep(const char *file, int line);
90 extern void __cant_sleep(const char *file, int line, int preempt_offset);
91 extern void __cant_migrate(const char *file, int line);
92
93 /**
94 * might_sleep - annotation for functions that can sleep
95 *
96 * this macro will print a stack trace if it is executed in an atomic
97 * context (spinlock, irq-handler, ...). Additional sections where blocking is
98 * not allowed can be annotated with non_block_start() and non_block_end()
99 * pairs.
100 *
101 * This is a useful debugging help to be able to catch problems early and not
102 * be bitten later when the calling function happens to sleep when it is not
103 * supposed to.
104 */
105 # define might_sleep() \
106 do { __might_sleep(__FILE__, __LINE__); might_resched(); } while (0)
107 /**
108 * cant_sleep - annotation for functions that cannot sleep
109 *
110 * this macro will print a stack trace if it is executed with preemption enabled
111 */
112 # define cant_sleep() \
113 do { __cant_sleep(__FILE__, __LINE__, 0); } while (0)
114 # define sched_annotate_sleep() (current->task_state_change = 0)
115
116 /**
117 * cant_migrate - annotation for functions that cannot migrate
118 *
119 * Will print a stack trace if executed in code which is migratable
120 */
121 # define cant_migrate() \
122 do { \
123 if (IS_ENABLED(CONFIG_SMP)) \
124 __cant_migrate(__FILE__, __LINE__); \
125 } while (0)
126
127 /**
128 * non_block_start - annotate the start of section where sleeping is prohibited
129 *
130 * This is on behalf of the oom reaper, specifically when it is calling the mmu
131 * notifiers. The problem is that if the notifier were to block on, for example,
132 * mutex_lock() and if the process which holds that mutex were to perform a
133 * sleeping memory allocation, the oom reaper is now blocked on completion of
134 * that memory allocation. Other blocking calls like wait_event() pose similar
135 * issues.
136 */
137 # define non_block_start() (current->non_block_count++)
138 /**
139 * non_block_end - annotate the end of section where sleeping is prohibited
140 *
141 * Closes a section opened by non_block_start().
142 */
143 # define non_block_end() WARN_ON(current->non_block_count-- == 0)
144 #else
__might_resched(const char * file,int line,unsigned int offsets)145 static inline void __might_resched(const char *file, int line,
146 unsigned int offsets) { }
__might_sleep(const char * file,int line)147 static inline void __might_sleep(const char *file, int line) { }
148 # define might_sleep() do { might_resched(); } while (0)
149 # define cant_sleep() do { } while (0)
150 # define cant_migrate() do { } while (0)
151 # define sched_annotate_sleep() do { } while (0)
152 # define non_block_start() do { } while (0)
153 # define non_block_end() do { } while (0)
154 #endif
155
156 #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
157
158 #if defined(CONFIG_MMU) && \
159 (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP))
160 #define might_fault() __might_fault(__FILE__, __LINE__)
161 void __might_fault(const char *file, int line);
162 #else
might_fault(void)163 static inline void might_fault(void) { }
164 #endif
165
166 void do_exit(long error_code) __noreturn;
167
168 extern int core_kernel_text(unsigned long addr);
169 extern int __kernel_text_address(unsigned long addr);
170 extern int kernel_text_address(unsigned long addr);
171 extern int func_ptr_is_kernel_text(void *ptr);
172
173 extern void bust_spinlocks(int yes);
174
175 extern int root_mountflags;
176
177 extern bool early_boot_irqs_disabled;
178
179 /*
180 * Values used for system_state. Ordering of the states must not be changed
181 * as code checks for <, <=, >, >= STATE.
182 */
183 extern enum system_states {
184 SYSTEM_BOOTING,
185 SYSTEM_SCHEDULING,
186 SYSTEM_FREEING_INITMEM,
187 SYSTEM_RUNNING,
188 SYSTEM_HALT,
189 SYSTEM_POWER_OFF,
190 SYSTEM_RESTART,
191 SYSTEM_SUSPEND,
192 } system_state;
193
194 /*
195 * General tracing related utility functions - trace_printk(),
196 * tracing_on/tracing_off and tracing_start()/tracing_stop
197 *
198 * Use tracing_on/tracing_off when you want to quickly turn on or off
199 * tracing. It simply enables or disables the recording of the trace events.
200 * This also corresponds to the user space /sys/kernel/tracing/tracing_on
201 * file, which gives a means for the kernel and userspace to interact.
202 * Place a tracing_off() in the kernel where you want tracing to end.
203 * From user space, examine the trace, and then echo 1 > tracing_on
204 * to continue tracing.
205 *
206 * tracing_stop/tracing_start has slightly more overhead. It is used
207 * by things like suspend to ram where disabling the recording of the
208 * trace is not enough, but tracing must actually stop because things
209 * like calling smp_processor_id() may crash the system.
210 *
211 * Most likely, you want to use tracing_on/tracing_off.
212 */
213
214 enum ftrace_dump_mode {
215 DUMP_NONE,
216 DUMP_ALL,
217 DUMP_ORIG,
218 DUMP_PARAM,
219 };
220
221 #ifdef CONFIG_TRACING
222 void tracing_on(void);
223 void tracing_off(void);
224 int tracing_is_on(void);
225 void tracing_snapshot(void);
226 void tracing_snapshot_alloc(void);
227
228 extern void tracing_start(void);
229 extern void tracing_stop(void);
230
231 static inline __printf(1, 2)
____trace_printk_check_format(const char * fmt,...)232 void ____trace_printk_check_format(const char *fmt, ...)
233 {
234 }
235 #define __trace_printk_check_format(fmt, args...) \
236 do { \
237 if (0) \
238 ____trace_printk_check_format(fmt, ##args); \
239 } while (0)
240
241 /**
242 * trace_printk - printf formatting in the ftrace buffer
243 * @fmt: the printf format for printing
244 *
245 * Note: __trace_printk is an internal function for trace_printk() and
246 * the @ip is passed in via the trace_printk() macro.
247 *
248 * This function allows a kernel developer to debug fast path sections
249 * that printk is not appropriate for. By scattering in various
250 * printk like tracing in the code, a developer can quickly see
251 * where problems are occurring.
252 *
253 * This is intended as a debugging tool for the developer only.
254 * Please refrain from leaving trace_printks scattered around in
255 * your code. (Extra memory is used for special buffers that are
256 * allocated when trace_printk() is used.)
257 *
258 * A little optimization trick is done here. If there's only one
259 * argument, there's no need to scan the string for printf formats.
260 * The trace_puts() will suffice. But how can we take advantage of
261 * using trace_puts() when trace_printk() has only one argument?
262 * By stringifying the args and checking the size we can tell
263 * whether or not there are args. __stringify((__VA_ARGS__)) will
264 * turn into "()\0" with a size of 3 when there are no args, anything
265 * else will be bigger. All we need to do is define a string to this,
266 * and then take its size and compare to 3. If it's bigger, use
267 * do_trace_printk() otherwise, optimize it to trace_puts(). Then just
268 * let gcc optimize the rest.
269 */
270
271 #define trace_printk(fmt, ...) \
272 do { \
273 char _______STR[] = __stringify((__VA_ARGS__)); \
274 if (sizeof(_______STR) > 3) \
275 do_trace_printk(fmt, ##__VA_ARGS__); \
276 else \
277 trace_puts(fmt); \
278 } while (0)
279
280 #define do_trace_printk(fmt, args...) \
281 do { \
282 static const char *trace_printk_fmt __used \
283 __section("__trace_printk_fmt") = \
284 __builtin_constant_p(fmt) ? fmt : NULL; \
285 \
286 __trace_printk_check_format(fmt, ##args); \
287 \
288 if (__builtin_constant_p(fmt)) \
289 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \
290 else \
291 __trace_printk(_THIS_IP_, fmt, ##args); \
292 } while (0)
293
294 extern __printf(2, 3)
295 int __trace_bprintk(unsigned long ip, const char *fmt, ...);
296
297 extern __printf(2, 3)
298 int __trace_printk(unsigned long ip, const char *fmt, ...);
299
300 /**
301 * trace_puts - write a string into the ftrace buffer
302 * @str: the string to record
303 *
304 * Note: __trace_bputs is an internal function for trace_puts and
305 * the @ip is passed in via the trace_puts macro.
306 *
307 * This is similar to trace_printk() but is made for those really fast
308 * paths that a developer wants the least amount of "Heisenbug" effects,
309 * where the processing of the print format is still too much.
310 *
311 * This function allows a kernel developer to debug fast path sections
312 * that printk is not appropriate for. By scattering in various
313 * printk like tracing in the code, a developer can quickly see
314 * where problems are occurring.
315 *
316 * This is intended as a debugging tool for the developer only.
317 * Please refrain from leaving trace_puts scattered around in
318 * your code. (Extra memory is used for special buffers that are
319 * allocated when trace_puts() is used.)
320 *
321 * Returns: 0 if nothing was written, positive # if string was.
322 * (1 when __trace_bputs is used, strlen(str) when __trace_puts is used)
323 */
324
325 #define trace_puts(str) ({ \
326 static const char *trace_printk_fmt __used \
327 __section("__trace_printk_fmt") = \
328 __builtin_constant_p(str) ? str : NULL; \
329 \
330 if (__builtin_constant_p(str)) \
331 __trace_bputs(_THIS_IP_, trace_printk_fmt); \
332 else \
333 __trace_puts(_THIS_IP_, str, strlen(str)); \
334 })
335 extern int __trace_bputs(unsigned long ip, const char *str);
336 extern int __trace_puts(unsigned long ip, const char *str, int size);
337
338 extern void trace_dump_stack(int skip);
339
340 /*
341 * The double __builtin_constant_p is because gcc will give us an error
342 * if we try to allocate the static variable to fmt if it is not a
343 * constant. Even with the outer if statement.
344 */
345 #define ftrace_vprintk(fmt, vargs) \
346 do { \
347 if (__builtin_constant_p(fmt)) { \
348 static const char *trace_printk_fmt __used \
349 __section("__trace_printk_fmt") = \
350 __builtin_constant_p(fmt) ? fmt : NULL; \
351 \
352 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs); \
353 } else \
354 __ftrace_vprintk(_THIS_IP_, fmt, vargs); \
355 } while (0)
356
357 extern __printf(2, 0) int
358 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
359
360 extern __printf(2, 0) int
361 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
362
363 extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
364 #else
tracing_start(void)365 static inline void tracing_start(void) { }
tracing_stop(void)366 static inline void tracing_stop(void) { }
trace_dump_stack(int skip)367 static inline void trace_dump_stack(int skip) { }
368
tracing_on(void)369 static inline void tracing_on(void) { }
tracing_off(void)370 static inline void tracing_off(void) { }
tracing_is_on(void)371 static inline int tracing_is_on(void) { return 0; }
tracing_snapshot(void)372 static inline void tracing_snapshot(void) { }
tracing_snapshot_alloc(void)373 static inline void tracing_snapshot_alloc(void) { }
374
375 static inline __printf(1, 2)
trace_printk(const char * fmt,...)376 int trace_printk(const char *fmt, ...)
377 {
378 return 0;
379 }
380 static __printf(1, 0) inline int
ftrace_vprintk(const char * fmt,va_list ap)381 ftrace_vprintk(const char *fmt, va_list ap)
382 {
383 return 0;
384 }
ftrace_dump(enum ftrace_dump_mode oops_dump_mode)385 static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
386 #endif /* CONFIG_TRACING */
387
388 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
389 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
390 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
391 #endif
392
393 /* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */
394 #define VERIFY_OCTAL_PERMISSIONS(perms) \
395 (BUILD_BUG_ON_ZERO((perms) < 0) + \
396 BUILD_BUG_ON_ZERO((perms) > 0777) + \
397 /* USER_READABLE >= GROUP_READABLE >= OTHER_READABLE */ \
398 BUILD_BUG_ON_ZERO((((perms) >> 6) & 4) < (((perms) >> 3) & 4)) + \
399 BUILD_BUG_ON_ZERO((((perms) >> 3) & 4) < ((perms) & 4)) + \
400 /* USER_WRITABLE >= GROUP_WRITABLE */ \
401 BUILD_BUG_ON_ZERO((((perms) >> 6) & 2) < (((perms) >> 3) & 2)) + \
402 /* OTHER_WRITABLE? Generally considered a bad idea. */ \
403 BUILD_BUG_ON_ZERO((perms) & 2) + \
404 (perms))
405 #endif
406