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_BUILD 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_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); 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__); 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_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) 177 #endif 178 179 #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0) 180 181 #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); 185 #else 186 static inline void might_fault(void) { } 187 #endif 188 189 void do_exit(long error_code) __noreturn; 190 void complete_and_exit(struct completion *, long) __noreturn; 191 192 extern int num_to_str(char *buf, int size, 193 unsigned long long num, unsigned int width); 194 195 /* lib/printf utilities */ 196 197 extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...); 198 extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list); 199 extern __printf(3, 4) 200 int snprintf(char *buf, size_t size, const char *fmt, ...); 201 extern __printf(3, 0) 202 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args); 203 extern __printf(3, 4) 204 int scnprintf(char *buf, size_t size, const char *fmt, ...); 205 extern __printf(3, 0) 206 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args); 207 extern __printf(2, 3) __malloc 208 char *kasprintf(gfp_t gfp, const char *fmt, ...); 209 extern __printf(2, 0) __malloc 210 char *kvasprintf(gfp_t gfp, const char *fmt, va_list args); 211 extern __printf(2, 0) 212 const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list args); 213 214 extern __scanf(2, 3) 215 int sscanf(const char *, const char *, ...); 216 extern __scanf(2, 0) 217 int vsscanf(const char *, const char *, va_list); 218 219 extern int no_hash_pointers_enable(char *str); 220 221 extern int get_option(char **str, int *pint); 222 extern char *get_options(const char *str, int nints, int *ints); 223 extern unsigned long long memparse(const char *ptr, char **retptr); 224 extern bool parse_option_str(const char *str, const char *option); 225 extern char *next_arg(char *args, char **param, char **val); 226 227 extern int core_kernel_text(unsigned long addr); 228 extern int __kernel_text_address(unsigned long addr); 229 extern int kernel_text_address(unsigned long addr); 230 extern int func_ptr_is_kernel_text(void *ptr); 231 232 extern void bust_spinlocks(int yes); 233 234 extern int root_mountflags; 235 236 extern bool early_boot_irqs_disabled; 237 238 /* 239 * Values used for system_state. Ordering of the states must not be changed 240 * as code checks for <, <=, >, >= STATE. 241 */ 242 extern enum system_states { 243 SYSTEM_BOOTING, 244 SYSTEM_SCHEDULING, 245 SYSTEM_FREEING_INITMEM, 246 SYSTEM_RUNNING, 247 SYSTEM_HALT, 248 SYSTEM_POWER_OFF, 249 SYSTEM_RESTART, 250 SYSTEM_SUSPEND, 251 } system_state; 252 253 extern const char hex_asc[]; 254 #define hex_asc_lo(x) hex_asc[((x) & 0x0f)] 255 #define hex_asc_hi(x) hex_asc[((x) & 0xf0) >> 4] 256 257 static inline char *hex_byte_pack(char *buf, u8 byte) 258 { 259 *buf++ = hex_asc_hi(byte); 260 *buf++ = hex_asc_lo(byte); 261 return buf; 262 } 263 264 extern const char hex_asc_upper[]; 265 #define hex_asc_upper_lo(x) hex_asc_upper[((x) & 0x0f)] 266 #define hex_asc_upper_hi(x) hex_asc_upper[((x) & 0xf0) >> 4] 267 268 static inline char *hex_byte_pack_upper(char *buf, u8 byte) 269 { 270 *buf++ = hex_asc_upper_hi(byte); 271 *buf++ = hex_asc_upper_lo(byte); 272 return buf; 273 } 274 275 extern int hex_to_bin(char ch); 276 extern int __must_check hex2bin(u8 *dst, const char *src, size_t count); 277 extern char *bin2hex(char *dst, const void *src, size_t count); 278 279 bool mac_pton(const char *s, u8 *mac); 280 281 /* 282 * General tracing related utility functions - trace_printk(), 283 * tracing_on/tracing_off and tracing_start()/tracing_stop 284 * 285 * Use tracing_on/tracing_off when you want to quickly turn on or off 286 * tracing. It simply enables or disables the recording of the trace events. 287 * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on 288 * file, which gives a means for the kernel and userspace to interact. 289 * Place a tracing_off() in the kernel where you want tracing to end. 290 * From user space, examine the trace, and then echo 1 > tracing_on 291 * to continue tracing. 292 * 293 * tracing_stop/tracing_start has slightly more overhead. It is used 294 * by things like suspend to ram where disabling the recording of the 295 * trace is not enough, but tracing must actually stop because things 296 * like calling smp_processor_id() may crash the system. 297 * 298 * Most likely, you want to use tracing_on/tracing_off. 299 */ 300 301 enum ftrace_dump_mode { 302 DUMP_NONE, 303 DUMP_ALL, 304 DUMP_ORIG, 305 }; 306 307 #ifdef CONFIG_TRACING 308 void tracing_on(void); 309 void tracing_off(void); 310 int tracing_is_on(void); 311 void tracing_snapshot(void); 312 void tracing_snapshot_alloc(void); 313 314 extern void tracing_start(void); 315 extern void tracing_stop(void); 316 317 static inline __printf(1, 2) 318 void ____trace_printk_check_format(const char *fmt, ...) 319 { 320 } 321 #define __trace_printk_check_format(fmt, args...) \ 322 do { \ 323 if (0) \ 324 ____trace_printk_check_format(fmt, ##args); \ 325 } while (0) 326 327 /** 328 * trace_printk - printf formatting in the ftrace buffer 329 * @fmt: the printf format for printing 330 * 331 * Note: __trace_printk is an internal function for trace_printk() and 332 * the @ip is passed in via the trace_printk() macro. 333 * 334 * This function allows a kernel developer to debug fast path sections 335 * that printk is not appropriate for. By scattering in various 336 * printk like tracing in the code, a developer can quickly see 337 * where problems are occurring. 338 * 339 * This is intended as a debugging tool for the developer only. 340 * Please refrain from leaving trace_printks scattered around in 341 * your code. (Extra memory is used for special buffers that are 342 * allocated when trace_printk() is used.) 343 * 344 * A little optimization trick is done here. If there's only one 345 * argument, there's no need to scan the string for printf formats. 346 * The trace_puts() will suffice. But how can we take advantage of 347 * using trace_puts() when trace_printk() has only one argument? 348 * By stringifying the args and checking the size we can tell 349 * whether or not there are args. __stringify((__VA_ARGS__)) will 350 * turn into "()\0" with a size of 3 when there are no args, anything 351 * else will be bigger. All we need to do is define a string to this, 352 * and then take its size and compare to 3. If it's bigger, use 353 * do_trace_printk() otherwise, optimize it to trace_puts(). Then just 354 * let gcc optimize the rest. 355 */ 356 357 #define trace_printk(fmt, ...) \ 358 do { \ 359 char _______STR[] = __stringify((__VA_ARGS__)); \ 360 if (sizeof(_______STR) > 3) \ 361 do_trace_printk(fmt, ##__VA_ARGS__); \ 362 else \ 363 trace_puts(fmt); \ 364 } while (0) 365 366 #define do_trace_printk(fmt, args...) \ 367 do { \ 368 static const char *trace_printk_fmt __used \ 369 __section("__trace_printk_fmt") = \ 370 __builtin_constant_p(fmt) ? fmt : NULL; \ 371 \ 372 __trace_printk_check_format(fmt, ##args); \ 373 \ 374 if (__builtin_constant_p(fmt)) \ 375 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \ 376 else \ 377 __trace_printk(_THIS_IP_, fmt, ##args); \ 378 } while (0) 379 380 extern __printf(2, 3) 381 int __trace_bprintk(unsigned long ip, const char *fmt, ...); 382 383 extern __printf(2, 3) 384 int __trace_printk(unsigned long ip, const char *fmt, ...); 385 386 /** 387 * trace_puts - write a string into the ftrace buffer 388 * @str: the string to record 389 * 390 * Note: __trace_bputs is an internal function for trace_puts and 391 * the @ip is passed in via the trace_puts macro. 392 * 393 * This is similar to trace_printk() but is made for those really fast 394 * paths that a developer wants the least amount of "Heisenbug" effects, 395 * where the processing of the print format is still too much. 396 * 397 * This function allows a kernel developer to debug fast path sections 398 * that printk is not appropriate for. By scattering in various 399 * printk like tracing in the code, a developer can quickly see 400 * where problems are occurring. 401 * 402 * This is intended as a debugging tool for the developer only. 403 * Please refrain from leaving trace_puts scattered around in 404 * your code. (Extra memory is used for special buffers that are 405 * allocated when trace_puts() is used.) 406 * 407 * Returns: 0 if nothing was written, positive # if string was. 408 * (1 when __trace_bputs is used, strlen(str) when __trace_puts is used) 409 */ 410 411 #define trace_puts(str) ({ \ 412 static const char *trace_printk_fmt __used \ 413 __section("__trace_printk_fmt") = \ 414 __builtin_constant_p(str) ? str : NULL; \ 415 \ 416 if (__builtin_constant_p(str)) \ 417 __trace_bputs(_THIS_IP_, trace_printk_fmt); \ 418 else \ 419 __trace_puts(_THIS_IP_, str, strlen(str)); \ 420 }) 421 extern int __trace_bputs(unsigned long ip, const char *str); 422 extern int __trace_puts(unsigned long ip, const char *str, int size); 423 424 extern void trace_dump_stack(int skip); 425 426 /* 427 * The double __builtin_constant_p is because gcc will give us an error 428 * if we try to allocate the static variable to fmt if it is not a 429 * constant. Even with the outer if statement. 430 */ 431 #define ftrace_vprintk(fmt, vargs) \ 432 do { \ 433 if (__builtin_constant_p(fmt)) { \ 434 static const char *trace_printk_fmt __used \ 435 __section("__trace_printk_fmt") = \ 436 __builtin_constant_p(fmt) ? fmt : NULL; \ 437 \ 438 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs); \ 439 } else \ 440 __ftrace_vprintk(_THIS_IP_, fmt, vargs); \ 441 } while (0) 442 443 extern __printf(2, 0) int 444 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap); 445 446 extern __printf(2, 0) int 447 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap); 448 449 extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode); 450 #else 451 static inline void tracing_start(void) { } 452 static inline void tracing_stop(void) { } 453 static inline void trace_dump_stack(int skip) { } 454 455 static inline void tracing_on(void) { } 456 static inline void tracing_off(void) { } 457 static inline int tracing_is_on(void) { return 0; } 458 static inline void tracing_snapshot(void) { } 459 static inline void tracing_snapshot_alloc(void) { } 460 461 static inline __printf(1, 2) 462 int trace_printk(const char *fmt, ...) 463 { 464 return 0; 465 } 466 static __printf(1, 0) inline int 467 ftrace_vprintk(const char *fmt, va_list ap) 468 { 469 return 0; 470 } 471 static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { } 472 #endif /* CONFIG_TRACING */ 473 474 /* This counts to 12. Any more, it will return 13th argument. */ 475 #define __COUNT_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _n, X...) _n 476 #define COUNT_ARGS(X...) __COUNT_ARGS(, ##X, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0) 477 478 #define __CONCAT(a, b) a ## b 479 #define CONCATENATE(a, b) __CONCAT(a, b) 480 481 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */ 482 #ifdef CONFIG_FTRACE_MCOUNT_RECORD 483 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD 484 #endif 485 486 /* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */ 487 #define VERIFY_OCTAL_PERMISSIONS(perms) \ 488 (BUILD_BUG_ON_ZERO((perms) < 0) + \ 489 BUILD_BUG_ON_ZERO((perms) > 0777) + \ 490 /* USER_READABLE >= GROUP_READABLE >= OTHER_READABLE */ \ 491 BUILD_BUG_ON_ZERO((((perms) >> 6) & 4) < (((perms) >> 3) & 4)) + \ 492 BUILD_BUG_ON_ZERO((((perms) >> 3) & 4) < ((perms) & 4)) + \ 493 /* USER_WRITABLE >= GROUP_WRITABLE */ \ 494 BUILD_BUG_ON_ZERO((((perms) >> 6) & 2) < (((perms) >> 3) & 2)) + \ 495 /* OTHER_WRITABLE? Generally considered a bad idea. */ \ 496 BUILD_BUG_ON_ZERO((perms) & 2) + \ 497 (perms)) 498 #endif 499