1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_KERNEL_H
3 #define _LINUX_KERNEL_H
5 #include <linux/stdarg.h>
6 #include <linux/align.h>
7 #include <linux/limits.h>
8 #include <linux/linkage.h>
9 #include <linux/stddef.h>
10 #include <linux/types.h>
11 #include <linux/compiler.h>
12 #include <linux/container_of.h>
13 #include <linux/bitops.h>
14 #include <linux/kstrtox.h>
15 #include <linux/log2.h>
16 #include <linux/math.h>
17 #include <linux/minmax.h>
18 #include <linux/typecheck.h>
19 #include <linux/panic.h>
20 #include <linux/printk.h>
21 #include <linux/build_bug.h>
22 #include <linux/static_call_types.h>
23 #include <linux/instruction_pointer.h>
24 #include <asm/byteorder.h>
26 #include <uapi/linux/kernel.h>
28 #define STACK_MAGIC 0xdeadbeef
31 * REPEAT_BYTE - repeat the value @x multiple times as an unsigned long value
34 * NOTE: @x is not checked for > 0xff; larger values produce odd results.
36 #define REPEAT_BYTE(x) ((~0ul / 0xff) * (x))
38 /* generic data direction definitions */
43 * ARRAY_SIZE - get the number of elements in array @arr
44 * @arr: array to be sized
46 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
48 #define PTR_IF(cond, ptr) ((cond) ? (ptr) : NULL)
50 #define u64_to_user_ptr(x) ( \
52 typecheck(u64, (x)); \
53 (void __user *)(uintptr_t)(x); \
58 * upper_32_bits - return bits 32-63 of a number
59 * @n: the number we're accessing
61 * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress
62 * the "right shift count >= width of type" warning when that quantity is
65 #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
68 * lower_32_bits - return bits 0-31 of a number
69 * @n: the number we're accessing
71 #define lower_32_bits(n) ((u32)((n) & 0xffffffff))
74 * upper_16_bits - return bits 16-31 of a number
75 * @n: the number we're accessing
77 #define upper_16_bits(n) ((u16)((n) >> 16))
80 * lower_16_bits - return bits 0-15 of a number
81 * @n: the number we're accessing
83 #define lower_16_bits(n) ((u16)((n) & 0xffff))
88 #ifdef CONFIG_PREEMPT_VOLUNTARY_BUILD
90 extern int __cond_resched(void);
91 # define might_resched() __cond_resched()
93 #elif defined(CONFIG_PREEMPT_DYNAMIC)
95 extern int __cond_resched(void);
97 DECLARE_STATIC_CALL(might_resched, __cond_resched);
99 static __always_inline void might_resched(void)
101 static_call_mod(might_resched)();
106 # define might_resched() do { } while (0)
108 #endif /* CONFIG_PREEMPT_* */
110 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
111 extern void __might_resched(const char *file, int line, unsigned int offsets);
112 extern void __might_sleep(const char *file, int line);
113 extern void __cant_sleep(const char *file, int line, int preempt_offset);
114 extern void __cant_migrate(const char *file, int line);
117 * might_sleep - annotation for functions that can sleep
119 * this macro will print a stack trace if it is executed in an atomic
120 * context (spinlock, irq-handler, ...). Additional sections where blocking is
121 * not allowed can be annotated with non_block_start() and non_block_end()
124 * This is a useful debugging help to be able to catch problems early and not
125 * be bitten later when the calling function happens to sleep when it is not
128 # define might_sleep() \
129 do { __might_sleep(__FILE__, __LINE__); might_resched(); } while (0)
131 * cant_sleep - annotation for functions that cannot sleep
133 * this macro will print a stack trace if it is executed with preemption enabled
135 # define cant_sleep() \
136 do { __cant_sleep(__FILE__, __LINE__, 0); } while (0)
137 # define sched_annotate_sleep() (current->task_state_change = 0)
140 * cant_migrate - annotation for functions that cannot migrate
142 * Will print a stack trace if executed in code which is migratable
144 # define cant_migrate() \
146 if (IS_ENABLED(CONFIG_SMP)) \
147 __cant_migrate(__FILE__, __LINE__); \
151 * non_block_start - annotate the start of section where sleeping is prohibited
153 * This is on behalf of the oom reaper, specifically when it is calling the mmu
154 * notifiers. The problem is that if the notifier were to block on, for example,
155 * mutex_lock() and if the process which holds that mutex were to perform a
156 * sleeping memory allocation, the oom reaper is now blocked on completion of
157 * that memory allocation. Other blocking calls like wait_event() pose similar
160 # define non_block_start() (current->non_block_count++)
162 * non_block_end - annotate the end of section where sleeping is prohibited
164 * Closes a section opened by non_block_start().
166 # define non_block_end() WARN_ON(current->non_block_count-- == 0)
168 static inline void __might_resched(const char *file, int line,
169 unsigned int offsets) { }
170 static inline void __might_sleep(const char *file, int line) { }
171 # define might_sleep() do { might_resched(); } while (0)
172 # define cant_sleep() do { } while (0)
173 # define cant_migrate() do { } while (0)
174 # define sched_annotate_sleep() do { } while (0)
175 # define non_block_start() do { } while (0)
176 # define non_block_end() do { } while (0)
179 #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
181 #if defined(CONFIG_MMU) && \
182 (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP))
183 #define might_fault() __might_fault(__FILE__, __LINE__)
184 void __might_fault(const char *file, int line);
186 static inline void might_fault(void) { }
189 void do_exit(long error_code) __noreturn;
191 extern int num_to_str(char *buf, int size,
192 unsigned long long num, unsigned int width);
194 /* lib/printf utilities */
196 extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
197 extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
198 extern __printf(3, 4)
199 int snprintf(char *buf, size_t size, const char *fmt, ...);
200 extern __printf(3, 0)
201 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
202 extern __printf(3, 4)
203 int scnprintf(char *buf, size_t size, const char *fmt, ...);
204 extern __printf(3, 0)
205 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
206 extern __printf(2, 3) __malloc
207 char *kasprintf(gfp_t gfp, const char *fmt, ...);
208 extern __printf(2, 0) __malloc
209 char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
210 extern __printf(2, 0)
211 const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list args);
214 int sscanf(const char *, const char *, ...);
216 int vsscanf(const char *, const char *, va_list);
218 extern int no_hash_pointers_enable(char *str);
220 extern int get_option(char **str, int *pint);
221 extern char *get_options(const char *str, int nints, int *ints);
222 extern unsigned long long memparse(const char *ptr, char **retptr);
223 extern bool parse_option_str(const char *str, const char *option);
224 extern char *next_arg(char *args, char **param, char **val);
226 extern int core_kernel_text(unsigned long addr);
227 extern int __kernel_text_address(unsigned long addr);
228 extern int kernel_text_address(unsigned long addr);
229 extern int func_ptr_is_kernel_text(void *ptr);
231 extern void bust_spinlocks(int yes);
233 extern int root_mountflags;
235 extern bool early_boot_irqs_disabled;
238 * Values used for system_state. Ordering of the states must not be changed
239 * as code checks for <, <=, >, >= STATE.
241 extern enum system_states {
244 SYSTEM_FREEING_INITMEM,
252 extern const char hex_asc[];
253 #define hex_asc_lo(x) hex_asc[((x) & 0x0f)]
254 #define hex_asc_hi(x) hex_asc[((x) & 0xf0) >> 4]
256 static inline char *hex_byte_pack(char *buf, u8 byte)
258 *buf++ = hex_asc_hi(byte);
259 *buf++ = hex_asc_lo(byte);
263 extern const char hex_asc_upper[];
264 #define hex_asc_upper_lo(x) hex_asc_upper[((x) & 0x0f)]
265 #define hex_asc_upper_hi(x) hex_asc_upper[((x) & 0xf0) >> 4]
267 static inline char *hex_byte_pack_upper(char *buf, u8 byte)
269 *buf++ = hex_asc_upper_hi(byte);
270 *buf++ = hex_asc_upper_lo(byte);
274 extern int hex_to_bin(char ch);
275 extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
276 extern char *bin2hex(char *dst, const void *src, size_t count);
278 bool mac_pton(const char *s, u8 *mac);
281 * General tracing related utility functions - trace_printk(),
282 * tracing_on/tracing_off and tracing_start()/tracing_stop
284 * Use tracing_on/tracing_off when you want to quickly turn on or off
285 * tracing. It simply enables or disables the recording of the trace events.
286 * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
287 * file, which gives a means for the kernel and userspace to interact.
288 * Place a tracing_off() in the kernel where you want tracing to end.
289 * From user space, examine the trace, and then echo 1 > tracing_on
290 * to continue tracing.
292 * tracing_stop/tracing_start has slightly more overhead. It is used
293 * by things like suspend to ram where disabling the recording of the
294 * trace is not enough, but tracing must actually stop because things
295 * like calling smp_processor_id() may crash the system.
297 * Most likely, you want to use tracing_on/tracing_off.
300 enum ftrace_dump_mode {
306 #ifdef CONFIG_TRACING
307 void tracing_on(void);
308 void tracing_off(void);
309 int tracing_is_on(void);
310 void tracing_snapshot(void);
311 void tracing_snapshot_alloc(void);
313 extern void tracing_start(void);
314 extern void tracing_stop(void);
316 static inline __printf(1, 2)
317 void ____trace_printk_check_format(const char *fmt, ...)
320 #define __trace_printk_check_format(fmt, args...) \
323 ____trace_printk_check_format(fmt, ##args); \
327 * trace_printk - printf formatting in the ftrace buffer
328 * @fmt: the printf format for printing
330 * Note: __trace_printk is an internal function for trace_printk() and
331 * the @ip is passed in via the trace_printk() macro.
333 * This function allows a kernel developer to debug fast path sections
334 * that printk is not appropriate for. By scattering in various
335 * printk like tracing in the code, a developer can quickly see
336 * where problems are occurring.
338 * This is intended as a debugging tool for the developer only.
339 * Please refrain from leaving trace_printks scattered around in
340 * your code. (Extra memory is used for special buffers that are
341 * allocated when trace_printk() is used.)
343 * A little optimization trick is done here. If there's only one
344 * argument, there's no need to scan the string for printf formats.
345 * The trace_puts() will suffice. But how can we take advantage of
346 * using trace_puts() when trace_printk() has only one argument?
347 * By stringifying the args and checking the size we can tell
348 * whether or not there are args. __stringify((__VA_ARGS__)) will
349 * turn into "()\0" with a size of 3 when there are no args, anything
350 * else will be bigger. All we need to do is define a string to this,
351 * and then take its size and compare to 3. If it's bigger, use
352 * do_trace_printk() otherwise, optimize it to trace_puts(). Then just
353 * let gcc optimize the rest.
356 #define trace_printk(fmt, ...) \
358 char _______STR[] = __stringify((__VA_ARGS__)); \
359 if (sizeof(_______STR) > 3) \
360 do_trace_printk(fmt, ##__VA_ARGS__); \
365 #define do_trace_printk(fmt, args...) \
367 static const char *trace_printk_fmt __used \
368 __section("__trace_printk_fmt") = \
369 __builtin_constant_p(fmt) ? fmt : NULL; \
371 __trace_printk_check_format(fmt, ##args); \
373 if (__builtin_constant_p(fmt)) \
374 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \
376 __trace_printk(_THIS_IP_, fmt, ##args); \
379 extern __printf(2, 3)
380 int __trace_bprintk(unsigned long ip, const char *fmt, ...);
382 extern __printf(2, 3)
383 int __trace_printk(unsigned long ip, const char *fmt, ...);
386 * trace_puts - write a string into the ftrace buffer
387 * @str: the string to record
389 * Note: __trace_bputs is an internal function for trace_puts and
390 * the @ip is passed in via the trace_puts macro.
392 * This is similar to trace_printk() but is made for those really fast
393 * paths that a developer wants the least amount of "Heisenbug" effects,
394 * where the processing of the print format is still too much.
396 * This function allows a kernel developer to debug fast path sections
397 * that printk is not appropriate for. By scattering in various
398 * printk like tracing in the code, a developer can quickly see
399 * where problems are occurring.
401 * This is intended as a debugging tool for the developer only.
402 * Please refrain from leaving trace_puts scattered around in
403 * your code. (Extra memory is used for special buffers that are
404 * allocated when trace_puts() is used.)
406 * Returns: 0 if nothing was written, positive # if string was.
407 * (1 when __trace_bputs is used, strlen(str) when __trace_puts is used)
410 #define trace_puts(str) ({ \
411 static const char *trace_printk_fmt __used \
412 __section("__trace_printk_fmt") = \
413 __builtin_constant_p(str) ? str : NULL; \
415 if (__builtin_constant_p(str)) \
416 __trace_bputs(_THIS_IP_, trace_printk_fmt); \
418 __trace_puts(_THIS_IP_, str, strlen(str)); \
420 extern int __trace_bputs(unsigned long ip, const char *str);
421 extern int __trace_puts(unsigned long ip, const char *str, int size);
423 extern void trace_dump_stack(int skip);
426 * The double __builtin_constant_p is because gcc will give us an error
427 * if we try to allocate the static variable to fmt if it is not a
428 * constant. Even with the outer if statement.
430 #define ftrace_vprintk(fmt, vargs) \
432 if (__builtin_constant_p(fmt)) { \
433 static const char *trace_printk_fmt __used \
434 __section("__trace_printk_fmt") = \
435 __builtin_constant_p(fmt) ? fmt : NULL; \
437 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs); \
439 __ftrace_vprintk(_THIS_IP_, fmt, vargs); \
442 extern __printf(2, 0) int
443 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
445 extern __printf(2, 0) int
446 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
448 extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
450 static inline void tracing_start(void) { }
451 static inline void tracing_stop(void) { }
452 static inline void trace_dump_stack(int skip) { }
454 static inline void tracing_on(void) { }
455 static inline void tracing_off(void) { }
456 static inline int tracing_is_on(void) { return 0; }
457 static inline void tracing_snapshot(void) { }
458 static inline void tracing_snapshot_alloc(void) { }
460 static inline __printf(1, 2)
461 int trace_printk(const char *fmt, ...)
465 static __printf(1, 0) inline int
466 ftrace_vprintk(const char *fmt, va_list ap)
470 static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
471 #endif /* CONFIG_TRACING */
473 /* This counts to 12. Any more, it will return 13th argument. */
474 #define __COUNT_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _n, X...) _n
475 #define COUNT_ARGS(X...) __COUNT_ARGS(, ##X, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
477 #define __CONCAT(a, b) a ## b
478 #define CONCATENATE(a, b) __CONCAT(a, b)
480 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
481 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
482 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
485 /* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */
486 #define VERIFY_OCTAL_PERMISSIONS(perms) \
487 (BUILD_BUG_ON_ZERO((perms) < 0) + \
488 BUILD_BUG_ON_ZERO((perms) > 0777) + \
489 /* USER_READABLE >= GROUP_READABLE >= OTHER_READABLE */ \
490 BUILD_BUG_ON_ZERO((((perms) >> 6) & 4) < (((perms) >> 3) & 4)) + \
491 BUILD_BUG_ON_ZERO((((perms) >> 3) & 4) < ((perms) & 4)) + \
492 /* USER_WRITABLE >= GROUP_WRITABLE */ \
493 BUILD_BUG_ON_ZERO((((perms) >> 6) & 2) < (((perms) >> 3) & 2)) + \
494 /* OTHER_WRITABLE? Generally considered a bad idea. */ \
495 BUILD_BUG_ON_ZERO((perms) & 2) + \