1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_KERNEL_H 3 #define _LINUX_KERNEL_H 4 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> 25 26 #include <uapi/linux/kernel.h> 27 28 #define STACK_MAGIC 0xdeadbeef 29 30 /** 31 * REPEAT_BYTE - repeat the value @x multiple times as an unsigned long value 32 * @x: value to repeat 33 * 34 * NOTE: @x is not checked for > 0xff; larger values produce odd results. 35 */ 36 #define REPEAT_BYTE(x) ((~0ul / 0xff) * (x)) 37 38 /* generic data direction definitions */ 39 #define READ 0 40 #define WRITE 1 41 42 /** 43 * ARRAY_SIZE - get the number of elements in array @arr 44 * @arr: array to be sized 45 */ 46 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr)) 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 /** 58 * upper_32_bits - return bits 32-63 of a number 59 * @n: the number we're accessing 60 * 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 63 * 32-bits. 64 */ 65 #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16)) 66 67 /** 68 * lower_32_bits - return bits 0-31 of a number 69 * @n: the number we're accessing 70 */ 71 #define lower_32_bits(n) ((u32)((n) & 0xffffffff)) 72 73 /** 74 * upper_16_bits - return bits 16-31 of a number 75 * @n: the number we're accessing 76 */ 77 #define upper_16_bits(n) ((u16)((n) >> 16)) 78 79 /** 80 * lower_16_bits - return bits 0-15 of a number 81 * @n: the number we're accessing 82 */ 83 #define lower_16_bits(n) ((u16)((n) & 0xffff)) 84 85 struct completion; 86 struct user; 87 88 #ifdef CONFIG_PREEMPT_VOLUNTARY 89 90 extern int __cond_resched(void); 91 # define might_resched() __cond_resched() 92 93 #elif defined(CONFIG_PREEMPT_DYNAMIC) 94 95 extern int __cond_resched(void); 96 97 DECLARE_STATIC_CALL(might_resched, __cond_resched); 98 99 static __always_inline void might_resched(void) 100 { 101 static_call_mod(might_resched)(); 102 } 103 104 #else 105 106 # define might_resched() do { } while (0) 107 108 #endif /* CONFIG_PREEMPT_* */ 109 110 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP 111 extern void ___might_sleep(const char *file, int line, int preempt_offset); 112 extern void __might_sleep(const char *file, int line, int preempt_offset); 113 extern void __cant_sleep(const char *file, int line, int preempt_offset); 114 extern void __cant_migrate(const char *file, int line); 115 116 /** 117 * might_sleep - annotation for functions that can sleep 118 * 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() 122 * pairs. 123 * 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 126 * supposed to. 127 */ 128 # define might_sleep() \ 129 do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0) 130 /** 131 * cant_sleep - annotation for functions that cannot sleep 132 * 133 * this macro will print a stack trace if it is executed with preemption enabled 134 */ 135 # define cant_sleep() \ 136 do { __cant_sleep(__FILE__, __LINE__, 0); } while (0) 137 # define sched_annotate_sleep() (current->task_state_change = 0) 138 139 /** 140 * cant_migrate - annotation for functions that cannot migrate 141 * 142 * Will print a stack trace if executed in code which is migratable 143 */ 144 # define cant_migrate() \ 145 do { \ 146 if (IS_ENABLED(CONFIG_SMP)) \ 147 __cant_migrate(__FILE__, __LINE__); \ 148 } while (0) 149 150 /** 151 * non_block_start - annotate the start of section where sleeping is prohibited 152 * 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 158 * issues. 159 */ 160 # define non_block_start() (current->non_block_count++) 161 /** 162 * non_block_end - annotate the end of section where sleeping is prohibited 163 * 164 * Closes a section opened by non_block_start(). 165 */ 166 # define non_block_end() WARN_ON(current->non_block_count-- == 0) 167 #else 168 static inline void ___might_sleep(const char *file, int line, 169 int preempt_offset) { } 170 static inline void __might_sleep(const char *file, int line, 171 int preempt_offset) { } 172 # define might_sleep() do { might_resched(); } while (0) 173 # define cant_sleep() do { } while (0) 174 # define cant_migrate() do { } while (0) 175 # define sched_annotate_sleep() do { } while (0) 176 # define non_block_start() do { } while (0) 177 # define non_block_end() do { } while (0) 178 #endif 179 180 #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0) 181 182 #if defined(CONFIG_MMU) && \ 183 (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP)) 184 #define might_fault() __might_fault(__FILE__, __LINE__) 185 void __might_fault(const char *file, int line); 186 #else 187 static inline void might_fault(void) { } 188 #endif 189 190 void do_exit(long error_code) __noreturn; 191 void complete_and_exit(struct completion *, long) __noreturn; 192 193 extern int num_to_str(char *buf, int size, 194 unsigned long long num, unsigned int width); 195 196 /* lib/printf utilities */ 197 198 extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...); 199 extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list); 200 extern __printf(3, 4) 201 int snprintf(char *buf, size_t size, const char *fmt, ...); 202 extern __printf(3, 0) 203 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args); 204 extern __printf(3, 4) 205 int scnprintf(char *buf, size_t size, const char *fmt, ...); 206 extern __printf(3, 0) 207 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args); 208 extern __printf(2, 3) __malloc 209 char *kasprintf(gfp_t gfp, const char *fmt, ...); 210 extern __printf(2, 0) __malloc 211 char *kvasprintf(gfp_t gfp, const char *fmt, va_list args); 212 extern __printf(2, 0) 213 const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list args); 214 215 extern __scanf(2, 3) 216 int sscanf(const char *, const char *, ...); 217 extern __scanf(2, 0) 218 int vsscanf(const char *, const char *, va_list); 219 220 extern int no_hash_pointers_enable(char *str); 221 222 extern int get_option(char **str, int *pint); 223 extern char *get_options(const char *str, int nints, int *ints); 224 extern unsigned long long memparse(const char *ptr, char **retptr); 225 extern bool parse_option_str(const char *str, const char *option); 226 extern char *next_arg(char *args, char **param, char **val); 227 228 extern int core_kernel_text(unsigned long addr); 229 extern int __kernel_text_address(unsigned long addr); 230 extern int kernel_text_address(unsigned long addr); 231 extern int func_ptr_is_kernel_text(void *ptr); 232 233 extern void bust_spinlocks(int yes); 234 235 extern int root_mountflags; 236 237 extern bool early_boot_irqs_disabled; 238 239 /* 240 * Values used for system_state. Ordering of the states must not be changed 241 * as code checks for <, <=, >, >= STATE. 242 */ 243 extern enum system_states { 244 SYSTEM_BOOTING, 245 SYSTEM_SCHEDULING, 246 SYSTEM_FREEING_INITMEM, 247 SYSTEM_RUNNING, 248 SYSTEM_HALT, 249 SYSTEM_POWER_OFF, 250 SYSTEM_RESTART, 251 SYSTEM_SUSPEND, 252 } system_state; 253 254 extern const char hex_asc[]; 255 #define hex_asc_lo(x) hex_asc[((x) & 0x0f)] 256 #define hex_asc_hi(x) hex_asc[((x) & 0xf0) >> 4] 257 258 static inline char *hex_byte_pack(char *buf, u8 byte) 259 { 260 *buf++ = hex_asc_hi(byte); 261 *buf++ = hex_asc_lo(byte); 262 return buf; 263 } 264 265 extern const char hex_asc_upper[]; 266 #define hex_asc_upper_lo(x) hex_asc_upper[((x) & 0x0f)] 267 #define hex_asc_upper_hi(x) hex_asc_upper[((x) & 0xf0) >> 4] 268 269 static inline char *hex_byte_pack_upper(char *buf, u8 byte) 270 { 271 *buf++ = hex_asc_upper_hi(byte); 272 *buf++ = hex_asc_upper_lo(byte); 273 return buf; 274 } 275 276 extern int hex_to_bin(char ch); 277 extern int __must_check hex2bin(u8 *dst, const char *src, size_t count); 278 extern char *bin2hex(char *dst, const void *src, size_t count); 279 280 bool mac_pton(const char *s, u8 *mac); 281 282 /* 283 * General tracing related utility functions - trace_printk(), 284 * tracing_on/tracing_off and tracing_start()/tracing_stop 285 * 286 * Use tracing_on/tracing_off when you want to quickly turn on or off 287 * tracing. It simply enables or disables the recording of the trace events. 288 * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on 289 * file, which gives a means for the kernel and userspace to interact. 290 * Place a tracing_off() in the kernel where you want tracing to end. 291 * From user space, examine the trace, and then echo 1 > tracing_on 292 * to continue tracing. 293 * 294 * tracing_stop/tracing_start has slightly more overhead. It is used 295 * by things like suspend to ram where disabling the recording of the 296 * trace is not enough, but tracing must actually stop because things 297 * like calling smp_processor_id() may crash the system. 298 * 299 * Most likely, you want to use tracing_on/tracing_off. 300 */ 301 302 enum ftrace_dump_mode { 303 DUMP_NONE, 304 DUMP_ALL, 305 DUMP_ORIG, 306 }; 307 308 #ifdef CONFIG_TRACING 309 void tracing_on(void); 310 void tracing_off(void); 311 int tracing_is_on(void); 312 void tracing_snapshot(void); 313 void tracing_snapshot_alloc(void); 314 315 extern void tracing_start(void); 316 extern void tracing_stop(void); 317 318 static inline __printf(1, 2) 319 void ____trace_printk_check_format(const char *fmt, ...) 320 { 321 } 322 #define __trace_printk_check_format(fmt, args...) \ 323 do { \ 324 if (0) \ 325 ____trace_printk_check_format(fmt, ##args); \ 326 } while (0) 327 328 /** 329 * trace_printk - printf formatting in the ftrace buffer 330 * @fmt: the printf format for printing 331 * 332 * Note: __trace_printk is an internal function for trace_printk() and 333 * the @ip is passed in via the trace_printk() macro. 334 * 335 * This function allows a kernel developer to debug fast path sections 336 * that printk is not appropriate for. By scattering in various 337 * printk like tracing in the code, a developer can quickly see 338 * where problems are occurring. 339 * 340 * This is intended as a debugging tool for the developer only. 341 * Please refrain from leaving trace_printks scattered around in 342 * your code. (Extra memory is used for special buffers that are 343 * allocated when trace_printk() is used.) 344 * 345 * A little optimization trick is done here. If there's only one 346 * argument, there's no need to scan the string for printf formats. 347 * The trace_puts() will suffice. But how can we take advantage of 348 * using trace_puts() when trace_printk() has only one argument? 349 * By stringifying the args and checking the size we can tell 350 * whether or not there are args. __stringify((__VA_ARGS__)) will 351 * turn into "()\0" with a size of 3 when there are no args, anything 352 * else will be bigger. All we need to do is define a string to this, 353 * and then take its size and compare to 3. If it's bigger, use 354 * do_trace_printk() otherwise, optimize it to trace_puts(). Then just 355 * let gcc optimize the rest. 356 */ 357 358 #define trace_printk(fmt, ...) \ 359 do { \ 360 char _______STR[] = __stringify((__VA_ARGS__)); \ 361 if (sizeof(_______STR) > 3) \ 362 do_trace_printk(fmt, ##__VA_ARGS__); \ 363 else \ 364 trace_puts(fmt); \ 365 } while (0) 366 367 #define do_trace_printk(fmt, args...) \ 368 do { \ 369 static const char *trace_printk_fmt __used \ 370 __section("__trace_printk_fmt") = \ 371 __builtin_constant_p(fmt) ? fmt : NULL; \ 372 \ 373 __trace_printk_check_format(fmt, ##args); \ 374 \ 375 if (__builtin_constant_p(fmt)) \ 376 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \ 377 else \ 378 __trace_printk(_THIS_IP_, fmt, ##args); \ 379 } while (0) 380 381 extern __printf(2, 3) 382 int __trace_bprintk(unsigned long ip, const char *fmt, ...); 383 384 extern __printf(2, 3) 385 int __trace_printk(unsigned long ip, const char *fmt, ...); 386 387 /** 388 * trace_puts - write a string into the ftrace buffer 389 * @str: the string to record 390 * 391 * Note: __trace_bputs is an internal function for trace_puts and 392 * the @ip is passed in via the trace_puts macro. 393 * 394 * This is similar to trace_printk() but is made for those really fast 395 * paths that a developer wants the least amount of "Heisenbug" effects, 396 * where the processing of the print format is still too much. 397 * 398 * This function allows a kernel developer to debug fast path sections 399 * that printk is not appropriate for. By scattering in various 400 * printk like tracing in the code, a developer can quickly see 401 * where problems are occurring. 402 * 403 * This is intended as a debugging tool for the developer only. 404 * Please refrain from leaving trace_puts scattered around in 405 * your code. (Extra memory is used for special buffers that are 406 * allocated when trace_puts() is used.) 407 * 408 * Returns: 0 if nothing was written, positive # if string was. 409 * (1 when __trace_bputs is used, strlen(str) when __trace_puts is used) 410 */ 411 412 #define trace_puts(str) ({ \ 413 static const char *trace_printk_fmt __used \ 414 __section("__trace_printk_fmt") = \ 415 __builtin_constant_p(str) ? str : NULL; \ 416 \ 417 if (__builtin_constant_p(str)) \ 418 __trace_bputs(_THIS_IP_, trace_printk_fmt); \ 419 else \ 420 __trace_puts(_THIS_IP_, str, strlen(str)); \ 421 }) 422 extern int __trace_bputs(unsigned long ip, const char *str); 423 extern int __trace_puts(unsigned long ip, const char *str, int size); 424 425 extern void trace_dump_stack(int skip); 426 427 /* 428 * The double __builtin_constant_p is because gcc will give us an error 429 * if we try to allocate the static variable to fmt if it is not a 430 * constant. Even with the outer if statement. 431 */ 432 #define ftrace_vprintk(fmt, vargs) \ 433 do { \ 434 if (__builtin_constant_p(fmt)) { \ 435 static const char *trace_printk_fmt __used \ 436 __section("__trace_printk_fmt") = \ 437 __builtin_constant_p(fmt) ? fmt : NULL; \ 438 \ 439 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs); \ 440 } else \ 441 __ftrace_vprintk(_THIS_IP_, fmt, vargs); \ 442 } while (0) 443 444 extern __printf(2, 0) int 445 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap); 446 447 extern __printf(2, 0) int 448 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap); 449 450 extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode); 451 #else 452 static inline void tracing_start(void) { } 453 static inline void tracing_stop(void) { } 454 static inline void trace_dump_stack(int skip) { } 455 456 static inline void tracing_on(void) { } 457 static inline void tracing_off(void) { } 458 static inline int tracing_is_on(void) { return 0; } 459 static inline void tracing_snapshot(void) { } 460 static inline void tracing_snapshot_alloc(void) { } 461 462 static inline __printf(1, 2) 463 int trace_printk(const char *fmt, ...) 464 { 465 return 0; 466 } 467 static __printf(1, 0) inline int 468 ftrace_vprintk(const char *fmt, va_list ap) 469 { 470 return 0; 471 } 472 static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { } 473 #endif /* CONFIG_TRACING */ 474 475 /* This counts to 12. Any more, it will return 13th argument. */ 476 #define __COUNT_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _n, X...) _n 477 #define COUNT_ARGS(X...) __COUNT_ARGS(, ##X, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0) 478 479 #define __CONCAT(a, b) a ## b 480 #define CONCATENATE(a, b) __CONCAT(a, b) 481 482 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */ 483 #ifdef CONFIG_FTRACE_MCOUNT_RECORD 484 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD 485 #endif 486 487 /* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */ 488 #define VERIFY_OCTAL_PERMISSIONS(perms) \ 489 (BUILD_BUG_ON_ZERO((perms) < 0) + \ 490 BUILD_BUG_ON_ZERO((perms) > 0777) + \ 491 /* USER_READABLE >= GROUP_READABLE >= OTHER_READABLE */ \ 492 BUILD_BUG_ON_ZERO((((perms) >> 6) & 4) < (((perms) >> 3) & 4)) + \ 493 BUILD_BUG_ON_ZERO((((perms) >> 3) & 4) < ((perms) & 4)) + \ 494 /* USER_WRITABLE >= GROUP_WRITABLE */ \ 495 BUILD_BUG_ON_ZERO((((perms) >> 6) & 2) < (((perms) >> 3) & 2)) + \ 496 /* OTHER_WRITABLE? Generally considered a bad idea. */ \ 497 BUILD_BUG_ON_ZERO((perms) & 2) + \ 498 (perms)) 499 #endif 500