1 /* SPDX-License-Identifier: GPL-2.0 */
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.
11 #ifndef _LINUX_KERNEL_H
12 #define _LINUX_KERNEL_H
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/kstrtox.h>
24 #include <linux/log2.h>
25 #include <linux/math.h>
26 #include <linux/minmax.h>
27 #include <linux/typecheck.h>
28 #include <linux/panic.h>
29 #include <linux/printk.h>
30 #include <linux/build_bug.h>
31 #include <linux/static_call_types.h>
32 #include <linux/instruction_pointer.h>
33 #include <asm/byteorder.h>
35 #include <uapi/linux/kernel.h>
37 #define STACK_MAGIC 0xdeadbeef
40 * REPEAT_BYTE - repeat the value @x multiple times as an unsigned long value
43 * NOTE: @x is not checked for > 0xff; larger values produce odd results.
45 #define REPEAT_BYTE(x) ((~0ul / 0xff) * (x))
47 /* generic data direction definitions */
52 * ARRAY_SIZE - get the number of elements in array @arr
53 * @arr: array to be sized
55 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
57 #define PTR_IF(cond, ptr) ((cond) ? (ptr) : NULL)
59 #define u64_to_user_ptr(x) ( \
61 typecheck(u64, (x)); \
62 (void __user *)(uintptr_t)(x); \
67 * upper_32_bits - return bits 32-63 of a number
68 * @n: the number we're accessing
70 * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress
71 * the "right shift count >= width of type" warning when that quantity is
74 #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
77 * lower_32_bits - return bits 0-31 of a number
78 * @n: the number we're accessing
80 #define lower_32_bits(n) ((u32)((n) & 0xffffffff))
83 * upper_16_bits - return bits 16-31 of a number
84 * @n: the number we're accessing
86 #define upper_16_bits(n) ((u16)((n) >> 16))
89 * lower_16_bits - return bits 0-15 of a number
90 * @n: the number we're accessing
92 #define lower_16_bits(n) ((u16)((n) & 0xffff))
97 #ifdef CONFIG_PREEMPT_VOLUNTARY_BUILD
99 extern int __cond_resched(void);
100 # define might_resched() __cond_resched()
102 #elif defined(CONFIG_PREEMPT_DYNAMIC)
104 extern int __cond_resched(void);
106 DECLARE_STATIC_CALL(might_resched, __cond_resched);
108 static __always_inline void might_resched(void)
110 static_call_mod(might_resched)();
115 # define might_resched() do { } while (0)
117 #endif /* CONFIG_PREEMPT_* */
119 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
120 extern void __might_resched(const char *file, int line, unsigned int offsets);
121 extern void __might_sleep(const char *file, int line);
122 extern void __cant_sleep(const char *file, int line, int preempt_offset);
123 extern void __cant_migrate(const char *file, int line);
126 * might_sleep - annotation for functions that can sleep
128 * this macro will print a stack trace if it is executed in an atomic
129 * context (spinlock, irq-handler, ...). Additional sections where blocking is
130 * not allowed can be annotated with non_block_start() and non_block_end()
133 * This is a useful debugging help to be able to catch problems early and not
134 * be bitten later when the calling function happens to sleep when it is not
137 # define might_sleep() \
138 do { __might_sleep(__FILE__, __LINE__); might_resched(); } while (0)
140 * cant_sleep - annotation for functions that cannot sleep
142 * this macro will print a stack trace if it is executed with preemption enabled
144 # define cant_sleep() \
145 do { __cant_sleep(__FILE__, __LINE__, 0); } while (0)
146 # define sched_annotate_sleep() (current->task_state_change = 0)
149 * cant_migrate - annotation for functions that cannot migrate
151 * Will print a stack trace if executed in code which is migratable
153 # define cant_migrate() \
155 if (IS_ENABLED(CONFIG_SMP)) \
156 __cant_migrate(__FILE__, __LINE__); \
160 * non_block_start - annotate the start of section where sleeping is prohibited
162 * This is on behalf of the oom reaper, specifically when it is calling the mmu
163 * notifiers. The problem is that if the notifier were to block on, for example,
164 * mutex_lock() and if the process which holds that mutex were to perform a
165 * sleeping memory allocation, the oom reaper is now blocked on completion of
166 * that memory allocation. Other blocking calls like wait_event() pose similar
169 # define non_block_start() (current->non_block_count++)
171 * non_block_end - annotate the end of section where sleeping is prohibited
173 * Closes a section opened by non_block_start().
175 # define non_block_end() WARN_ON(current->non_block_count-- == 0)
177 static inline void __might_resched(const char *file, int line,
178 unsigned int offsets) { }
179 static inline void __might_sleep(const char *file, int line) { }
180 # define might_sleep() do { might_resched(); } while (0)
181 # define cant_sleep() do { } while (0)
182 # define cant_migrate() do { } while (0)
183 # define sched_annotate_sleep() do { } while (0)
184 # define non_block_start() do { } while (0)
185 # define non_block_end() do { } while (0)
188 #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
190 #if defined(CONFIG_MMU) && \
191 (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP))
192 #define might_fault() __might_fault(__FILE__, __LINE__)
193 void __might_fault(const char *file, int line);
195 static inline void might_fault(void) { }
198 void do_exit(long error_code) __noreturn;
200 extern int num_to_str(char *buf, int size,
201 unsigned long long num, unsigned int width);
203 /* lib/printf utilities */
205 extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
206 extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
207 extern __printf(3, 4)
208 int snprintf(char *buf, size_t size, const char *fmt, ...);
209 extern __printf(3, 0)
210 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
211 extern __printf(3, 4)
212 int scnprintf(char *buf, size_t size, const char *fmt, ...);
213 extern __printf(3, 0)
214 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
215 extern __printf(2, 3) __malloc
216 char *kasprintf(gfp_t gfp, const char *fmt, ...);
217 extern __printf(2, 0) __malloc
218 char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
219 extern __printf(2, 0)
220 const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list args);
223 int sscanf(const char *, const char *, ...);
225 int vsscanf(const char *, const char *, va_list);
227 extern int no_hash_pointers_enable(char *str);
229 extern int get_option(char **str, int *pint);
230 extern char *get_options(const char *str, int nints, int *ints);
231 extern unsigned long long memparse(const char *ptr, char **retptr);
232 extern bool parse_option_str(const char *str, const char *option);
233 extern char *next_arg(char *args, char **param, char **val);
235 extern int core_kernel_text(unsigned long addr);
236 extern int __kernel_text_address(unsigned long addr);
237 extern int kernel_text_address(unsigned long addr);
238 extern int func_ptr_is_kernel_text(void *ptr);
240 extern void bust_spinlocks(int yes);
242 extern int root_mountflags;
244 extern bool early_boot_irqs_disabled;
247 * Values used for system_state. Ordering of the states must not be changed
248 * as code checks for <, <=, >, >= STATE.
250 extern enum system_states {
253 SYSTEM_FREEING_INITMEM,
261 extern const char hex_asc[];
262 #define hex_asc_lo(x) hex_asc[((x) & 0x0f)]
263 #define hex_asc_hi(x) hex_asc[((x) & 0xf0) >> 4]
265 static inline char *hex_byte_pack(char *buf, u8 byte)
267 *buf++ = hex_asc_hi(byte);
268 *buf++ = hex_asc_lo(byte);
272 extern const char hex_asc_upper[];
273 #define hex_asc_upper_lo(x) hex_asc_upper[((x) & 0x0f)]
274 #define hex_asc_upper_hi(x) hex_asc_upper[((x) & 0xf0) >> 4]
276 static inline char *hex_byte_pack_upper(char *buf, u8 byte)
278 *buf++ = hex_asc_upper_hi(byte);
279 *buf++ = hex_asc_upper_lo(byte);
283 extern int hex_to_bin(char ch);
284 extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
285 extern char *bin2hex(char *dst, const void *src, size_t count);
287 bool mac_pton(const char *s, u8 *mac);
290 * General tracing related utility functions - trace_printk(),
291 * tracing_on/tracing_off and tracing_start()/tracing_stop
293 * Use tracing_on/tracing_off when you want to quickly turn on or off
294 * tracing. It simply enables or disables the recording of the trace events.
295 * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
296 * file, which gives a means for the kernel and userspace to interact.
297 * Place a tracing_off() in the kernel where you want tracing to end.
298 * From user space, examine the trace, and then echo 1 > tracing_on
299 * to continue tracing.
301 * tracing_stop/tracing_start has slightly more overhead. It is used
302 * by things like suspend to ram where disabling the recording of the
303 * trace is not enough, but tracing must actually stop because things
304 * like calling smp_processor_id() may crash the system.
306 * Most likely, you want to use tracing_on/tracing_off.
309 enum ftrace_dump_mode {
315 #ifdef CONFIG_TRACING
316 void tracing_on(void);
317 void tracing_off(void);
318 int tracing_is_on(void);
319 void tracing_snapshot(void);
320 void tracing_snapshot_alloc(void);
322 extern void tracing_start(void);
323 extern void tracing_stop(void);
325 static inline __printf(1, 2)
326 void ____trace_printk_check_format(const char *fmt, ...)
329 #define __trace_printk_check_format(fmt, args...) \
332 ____trace_printk_check_format(fmt, ##args); \
336 * trace_printk - printf formatting in the ftrace buffer
337 * @fmt: the printf format for printing
339 * Note: __trace_printk is an internal function for trace_printk() and
340 * the @ip is passed in via the trace_printk() macro.
342 * This function allows a kernel developer to debug fast path sections
343 * that printk is not appropriate for. By scattering in various
344 * printk like tracing in the code, a developer can quickly see
345 * where problems are occurring.
347 * This is intended as a debugging tool for the developer only.
348 * Please refrain from leaving trace_printks scattered around in
349 * your code. (Extra memory is used for special buffers that are
350 * allocated when trace_printk() is used.)
352 * A little optimization trick is done here. If there's only one
353 * argument, there's no need to scan the string for printf formats.
354 * The trace_puts() will suffice. But how can we take advantage of
355 * using trace_puts() when trace_printk() has only one argument?
356 * By stringifying the args and checking the size we can tell
357 * whether or not there are args. __stringify((__VA_ARGS__)) will
358 * turn into "()\0" with a size of 3 when there are no args, anything
359 * else will be bigger. All we need to do is define a string to this,
360 * and then take its size and compare to 3. If it's bigger, use
361 * do_trace_printk() otherwise, optimize it to trace_puts(). Then just
362 * let gcc optimize the rest.
365 #define trace_printk(fmt, ...) \
367 char _______STR[] = __stringify((__VA_ARGS__)); \
368 if (sizeof(_______STR) > 3) \
369 do_trace_printk(fmt, ##__VA_ARGS__); \
374 #define do_trace_printk(fmt, args...) \
376 static const char *trace_printk_fmt __used \
377 __section("__trace_printk_fmt") = \
378 __builtin_constant_p(fmt) ? fmt : NULL; \
380 __trace_printk_check_format(fmt, ##args); \
382 if (__builtin_constant_p(fmt)) \
383 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \
385 __trace_printk(_THIS_IP_, fmt, ##args); \
388 extern __printf(2, 3)
389 int __trace_bprintk(unsigned long ip, const char *fmt, ...);
391 extern __printf(2, 3)
392 int __trace_printk(unsigned long ip, const char *fmt, ...);
395 * trace_puts - write a string into the ftrace buffer
396 * @str: the string to record
398 * Note: __trace_bputs is an internal function for trace_puts and
399 * the @ip is passed in via the trace_puts macro.
401 * This is similar to trace_printk() but is made for those really fast
402 * paths that a developer wants the least amount of "Heisenbug" effects,
403 * where the processing of the print format is still too much.
405 * This function allows a kernel developer to debug fast path sections
406 * that printk is not appropriate for. By scattering in various
407 * printk like tracing in the code, a developer can quickly see
408 * where problems are occurring.
410 * This is intended as a debugging tool for the developer only.
411 * Please refrain from leaving trace_puts scattered around in
412 * your code. (Extra memory is used for special buffers that are
413 * allocated when trace_puts() is used.)
415 * Returns: 0 if nothing was written, positive # if string was.
416 * (1 when __trace_bputs is used, strlen(str) when __trace_puts is used)
419 #define trace_puts(str) ({ \
420 static const char *trace_printk_fmt __used \
421 __section("__trace_printk_fmt") = \
422 __builtin_constant_p(str) ? str : NULL; \
424 if (__builtin_constant_p(str)) \
425 __trace_bputs(_THIS_IP_, trace_printk_fmt); \
427 __trace_puts(_THIS_IP_, str, strlen(str)); \
429 extern int __trace_bputs(unsigned long ip, const char *str);
430 extern int __trace_puts(unsigned long ip, const char *str, int size);
432 extern void trace_dump_stack(int skip);
435 * The double __builtin_constant_p is because gcc will give us an error
436 * if we try to allocate the static variable to fmt if it is not a
437 * constant. Even with the outer if statement.
439 #define ftrace_vprintk(fmt, vargs) \
441 if (__builtin_constant_p(fmt)) { \
442 static const char *trace_printk_fmt __used \
443 __section("__trace_printk_fmt") = \
444 __builtin_constant_p(fmt) ? fmt : NULL; \
446 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs); \
448 __ftrace_vprintk(_THIS_IP_, fmt, vargs); \
451 extern __printf(2, 0) int
452 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
454 extern __printf(2, 0) int
455 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
457 extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
459 static inline void tracing_start(void) { }
460 static inline void tracing_stop(void) { }
461 static inline void trace_dump_stack(int skip) { }
463 static inline void tracing_on(void) { }
464 static inline void tracing_off(void) { }
465 static inline int tracing_is_on(void) { return 0; }
466 static inline void tracing_snapshot(void) { }
467 static inline void tracing_snapshot_alloc(void) { }
469 static inline __printf(1, 2)
470 int trace_printk(const char *fmt, ...)
474 static __printf(1, 0) inline int
475 ftrace_vprintk(const char *fmt, va_list ap)
479 static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
480 #endif /* CONFIG_TRACING */
482 /* This counts to 12. Any more, it will return 13th argument. */
483 #define __COUNT_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _n, X...) _n
484 #define COUNT_ARGS(X...) __COUNT_ARGS(, ##X, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
486 #define __CONCAT(a, b) a ## b
487 #define CONCATENATE(a, b) __CONCAT(a, b)
489 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
490 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
491 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
494 /* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */
495 #define VERIFY_OCTAL_PERMISSIONS(perms) \
496 (BUILD_BUG_ON_ZERO((perms) < 0) + \
497 BUILD_BUG_ON_ZERO((perms) > 0777) + \
498 /* USER_READABLE >= GROUP_READABLE >= OTHER_READABLE */ \
499 BUILD_BUG_ON_ZERO((((perms) >> 6) & 4) < (((perms) >> 3) & 4)) + \
500 BUILD_BUG_ON_ZERO((((perms) >> 3) & 4) < ((perms) & 4)) + \
501 /* USER_WRITABLE >= GROUP_WRITABLE */ \
502 BUILD_BUG_ON_ZERO((((perms) >> 6) & 2) < (((perms) >> 3) & 2)) + \
503 /* OTHER_WRITABLE? Generally considered a bad idea. */ \
504 BUILD_BUG_ON_ZERO((perms) & 2) + \