1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_KERNEL_H 3 #define _LINUX_KERNEL_H 4 5 #include <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/bitops.h> 13 #include <linux/log2.h> 14 #include <linux/math.h> 15 #include <linux/minmax.h> 16 #include <linux/typecheck.h> 17 #include <linux/printk.h> 18 #include <linux/build_bug.h> 19 #include <linux/static_call_types.h> 20 #include <asm/byteorder.h> 21 22 #include <uapi/linux/kernel.h> 23 24 #define STACK_MAGIC 0xdeadbeef 25 26 /** 27 * REPEAT_BYTE - repeat the value @x multiple times as an unsigned long value 28 * @x: value to repeat 29 * 30 * NOTE: @x is not checked for > 0xff; larger values produce odd results. 31 */ 32 #define REPEAT_BYTE(x) ((~0ul / 0xff) * (x)) 33 34 /* generic data direction definitions */ 35 #define READ 0 36 #define WRITE 1 37 38 /** 39 * ARRAY_SIZE - get the number of elements in array @arr 40 * @arr: array to be sized 41 */ 42 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr)) 43 44 #define PTR_IF(cond, ptr) ((cond) ? (ptr) : NULL) 45 46 #define u64_to_user_ptr(x) ( \ 47 { \ 48 typecheck(u64, (x)); \ 49 (void __user *)(uintptr_t)(x); \ 50 } \ 51 ) 52 53 #define typeof_member(T, m) typeof(((T*)0)->m) 54 55 #define _RET_IP_ (unsigned long)__builtin_return_address(0) 56 #define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; }) 57 58 /** 59 * upper_32_bits - return bits 32-63 of a number 60 * @n: the number we're accessing 61 * 62 * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress 63 * the "right shift count >= width of type" warning when that quantity is 64 * 32-bits. 65 */ 66 #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16)) 67 68 /** 69 * lower_32_bits - return bits 0-31 of a number 70 * @n: the number we're accessing 71 */ 72 #define lower_32_bits(n) ((u32)((n) & 0xffffffff)) 73 74 struct completion; 75 struct pt_regs; 76 struct user; 77 78 #ifdef CONFIG_PREEMPT_VOLUNTARY 79 80 extern int __cond_resched(void); 81 # define might_resched() __cond_resched() 82 83 #elif defined(CONFIG_PREEMPT_DYNAMIC) 84 85 extern int __cond_resched(void); 86 87 DECLARE_STATIC_CALL(might_resched, __cond_resched); 88 89 static __always_inline void might_resched(void) 90 { 91 static_call_mod(might_resched)(); 92 } 93 94 #else 95 96 # define might_resched() do { } while (0) 97 98 #endif /* CONFIG_PREEMPT_* */ 99 100 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP 101 extern void ___might_sleep(const char *file, int line, int preempt_offset); 102 extern void __might_sleep(const char *file, int line, int preempt_offset); 103 extern void __cant_sleep(const char *file, int line, int preempt_offset); 104 extern void __cant_migrate(const char *file, int line); 105 106 /** 107 * might_sleep - annotation for functions that can sleep 108 * 109 * this macro will print a stack trace if it is executed in an atomic 110 * context (spinlock, irq-handler, ...). Additional sections where blocking is 111 * not allowed can be annotated with non_block_start() and non_block_end() 112 * pairs. 113 * 114 * This is a useful debugging help to be able to catch problems early and not 115 * be bitten later when the calling function happens to sleep when it is not 116 * supposed to. 117 */ 118 # define might_sleep() \ 119 do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0) 120 /** 121 * cant_sleep - annotation for functions that cannot sleep 122 * 123 * this macro will print a stack trace if it is executed with preemption enabled 124 */ 125 # define cant_sleep() \ 126 do { __cant_sleep(__FILE__, __LINE__, 0); } while (0) 127 # define sched_annotate_sleep() (current->task_state_change = 0) 128 129 /** 130 * cant_migrate - annotation for functions that cannot migrate 131 * 132 * Will print a stack trace if executed in code which is migratable 133 */ 134 # define cant_migrate() \ 135 do { \ 136 if (IS_ENABLED(CONFIG_SMP)) \ 137 __cant_migrate(__FILE__, __LINE__); \ 138 } while (0) 139 140 /** 141 * non_block_start - annotate the start of section where sleeping is prohibited 142 * 143 * This is on behalf of the oom reaper, specifically when it is calling the mmu 144 * notifiers. The problem is that if the notifier were to block on, for example, 145 * mutex_lock() and if the process which holds that mutex were to perform a 146 * sleeping memory allocation, the oom reaper is now blocked on completion of 147 * that memory allocation. Other blocking calls like wait_event() pose similar 148 * issues. 149 */ 150 # define non_block_start() (current->non_block_count++) 151 /** 152 * non_block_end - annotate the end of section where sleeping is prohibited 153 * 154 * Closes a section opened by non_block_start(). 155 */ 156 # define non_block_end() WARN_ON(current->non_block_count-- == 0) 157 #else 158 static inline void ___might_sleep(const char *file, int line, 159 int preempt_offset) { } 160 static inline void __might_sleep(const char *file, int line, 161 int preempt_offset) { } 162 # define might_sleep() do { might_resched(); } while (0) 163 # define cant_sleep() do { } while (0) 164 # define cant_migrate() do { } while (0) 165 # define sched_annotate_sleep() do { } while (0) 166 # define non_block_start() do { } while (0) 167 # define non_block_end() do { } while (0) 168 #endif 169 170 #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0) 171 172 #if defined(CONFIG_MMU) && \ 173 (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP)) 174 #define might_fault() __might_fault(__FILE__, __LINE__) 175 void __might_fault(const char *file, int line); 176 #else 177 static inline void might_fault(void) { } 178 #endif 179 180 extern struct atomic_notifier_head panic_notifier_list; 181 extern long (*panic_blink)(int state); 182 __printf(1, 2) 183 void panic(const char *fmt, ...) __noreturn __cold; 184 void nmi_panic(struct pt_regs *regs, const char *msg); 185 extern void oops_enter(void); 186 extern void oops_exit(void); 187 extern bool oops_may_print(void); 188 void do_exit(long error_code) __noreturn; 189 void complete_and_exit(struct completion *, long) __noreturn; 190 191 /* Internal, do not use. */ 192 int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res); 193 int __must_check _kstrtol(const char *s, unsigned int base, long *res); 194 195 int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res); 196 int __must_check kstrtoll(const char *s, unsigned int base, long long *res); 197 198 /** 199 * kstrtoul - convert a string to an unsigned long 200 * @s: The start of the string. The string must be null-terminated, and may also 201 * include a single newline before its terminating null. The first character 202 * may also be a plus sign, but not a minus sign. 203 * @base: The number base to use. The maximum supported base is 16. If base is 204 * given as 0, then the base of the string is automatically detected with the 205 * conventional semantics - If it begins with 0x the number will be parsed as a 206 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be 207 * parsed as an octal number. Otherwise it will be parsed as a decimal. 208 * @res: Where to write the result of the conversion on success. 209 * 210 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error. 211 * Preferred over simple_strtoul(). Return code must be checked. 212 */ 213 static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res) 214 { 215 /* 216 * We want to shortcut function call, but 217 * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0. 218 */ 219 if (sizeof(unsigned long) == sizeof(unsigned long long) && 220 __alignof__(unsigned long) == __alignof__(unsigned long long)) 221 return kstrtoull(s, base, (unsigned long long *)res); 222 else 223 return _kstrtoul(s, base, res); 224 } 225 226 /** 227 * kstrtol - convert a string to a long 228 * @s: The start of the string. The string must be null-terminated, and may also 229 * include a single newline before its terminating null. The first character 230 * may also be a plus sign or a minus sign. 231 * @base: The number base to use. The maximum supported base is 16. If base is 232 * given as 0, then the base of the string is automatically detected with the 233 * conventional semantics - If it begins with 0x the number will be parsed as a 234 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be 235 * parsed as an octal number. Otherwise it will be parsed as a decimal. 236 * @res: Where to write the result of the conversion on success. 237 * 238 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error. 239 * Preferred over simple_strtol(). Return code must be checked. 240 */ 241 static inline int __must_check kstrtol(const char *s, unsigned int base, long *res) 242 { 243 /* 244 * We want to shortcut function call, but 245 * __builtin_types_compatible_p(long, long long) = 0. 246 */ 247 if (sizeof(long) == sizeof(long long) && 248 __alignof__(long) == __alignof__(long long)) 249 return kstrtoll(s, base, (long long *)res); 250 else 251 return _kstrtol(s, base, res); 252 } 253 254 int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res); 255 int __must_check kstrtoint(const char *s, unsigned int base, int *res); 256 257 static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res) 258 { 259 return kstrtoull(s, base, res); 260 } 261 262 static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res) 263 { 264 return kstrtoll(s, base, res); 265 } 266 267 static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res) 268 { 269 return kstrtouint(s, base, res); 270 } 271 272 static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res) 273 { 274 return kstrtoint(s, base, res); 275 } 276 277 int __must_check kstrtou16(const char *s, unsigned int base, u16 *res); 278 int __must_check kstrtos16(const char *s, unsigned int base, s16 *res); 279 int __must_check kstrtou8(const char *s, unsigned int base, u8 *res); 280 int __must_check kstrtos8(const char *s, unsigned int base, s8 *res); 281 int __must_check kstrtobool(const char *s, bool *res); 282 283 int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res); 284 int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res); 285 int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res); 286 int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res); 287 int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res); 288 int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res); 289 int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res); 290 int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res); 291 int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res); 292 int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res); 293 int __must_check kstrtobool_from_user(const char __user *s, size_t count, bool *res); 294 295 static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res) 296 { 297 return kstrtoull_from_user(s, count, base, res); 298 } 299 300 static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res) 301 { 302 return kstrtoll_from_user(s, count, base, res); 303 } 304 305 static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res) 306 { 307 return kstrtouint_from_user(s, count, base, res); 308 } 309 310 static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res) 311 { 312 return kstrtoint_from_user(s, count, base, res); 313 } 314 315 /* 316 * Use kstrto<foo> instead. 317 * 318 * NOTE: simple_strto<foo> does not check for the range overflow and, 319 * depending on the input, may give interesting results. 320 * 321 * Use these functions if and only if you cannot use kstrto<foo>, because 322 * the conversion ends on the first non-digit character, which may be far 323 * beyond the supported range. It might be useful to parse the strings like 324 * 10x50 or 12:21 without altering original string or temporary buffer in use. 325 * Keep in mind above caveat. 326 */ 327 328 extern unsigned long simple_strtoul(const char *,char **,unsigned int); 329 extern long simple_strtol(const char *,char **,unsigned int); 330 extern unsigned long long simple_strtoull(const char *,char **,unsigned int); 331 extern long long simple_strtoll(const char *,char **,unsigned int); 332 333 extern int num_to_str(char *buf, int size, 334 unsigned long long num, unsigned int width); 335 336 /* lib/printf utilities */ 337 338 extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...); 339 extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list); 340 extern __printf(3, 4) 341 int snprintf(char *buf, size_t size, const char *fmt, ...); 342 extern __printf(3, 0) 343 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args); 344 extern __printf(3, 4) 345 int scnprintf(char *buf, size_t size, const char *fmt, ...); 346 extern __printf(3, 0) 347 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args); 348 extern __printf(2, 3) __malloc 349 char *kasprintf(gfp_t gfp, const char *fmt, ...); 350 extern __printf(2, 0) __malloc 351 char *kvasprintf(gfp_t gfp, const char *fmt, va_list args); 352 extern __printf(2, 0) 353 const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list args); 354 355 extern __scanf(2, 3) 356 int sscanf(const char *, const char *, ...); 357 extern __scanf(2, 0) 358 int vsscanf(const char *, const char *, va_list); 359 360 extern int get_option(char **str, int *pint); 361 extern char *get_options(const char *str, int nints, int *ints); 362 extern unsigned long long memparse(const char *ptr, char **retptr); 363 extern bool parse_option_str(const char *str, const char *option); 364 extern char *next_arg(char *args, char **param, char **val); 365 366 extern int core_kernel_text(unsigned long addr); 367 extern int init_kernel_text(unsigned long addr); 368 extern int core_kernel_data(unsigned long addr); 369 extern int __kernel_text_address(unsigned long addr); 370 extern int kernel_text_address(unsigned long addr); 371 extern int func_ptr_is_kernel_text(void *ptr); 372 373 #ifdef CONFIG_SMP 374 extern unsigned int sysctl_oops_all_cpu_backtrace; 375 #else 376 #define sysctl_oops_all_cpu_backtrace 0 377 #endif /* CONFIG_SMP */ 378 379 extern void bust_spinlocks(int yes); 380 extern int panic_timeout; 381 extern unsigned long panic_print; 382 extern int panic_on_oops; 383 extern int panic_on_unrecovered_nmi; 384 extern int panic_on_io_nmi; 385 extern int panic_on_warn; 386 extern unsigned long panic_on_taint; 387 extern bool panic_on_taint_nousertaint; 388 extern int sysctl_panic_on_rcu_stall; 389 extern int sysctl_max_rcu_stall_to_panic; 390 extern int sysctl_panic_on_stackoverflow; 391 392 extern bool crash_kexec_post_notifiers; 393 394 /* 395 * panic_cpu is used for synchronizing panic() and crash_kexec() execution. It 396 * holds a CPU number which is executing panic() currently. A value of 397 * PANIC_CPU_INVALID means no CPU has entered panic() or crash_kexec(). 398 */ 399 extern atomic_t panic_cpu; 400 #define PANIC_CPU_INVALID -1 401 402 /* 403 * Only to be used by arch init code. If the user over-wrote the default 404 * CONFIG_PANIC_TIMEOUT, honor it. 405 */ 406 static inline void set_arch_panic_timeout(int timeout, int arch_default_timeout) 407 { 408 if (panic_timeout == arch_default_timeout) 409 panic_timeout = timeout; 410 } 411 extern const char *print_tainted(void); 412 enum lockdep_ok { 413 LOCKDEP_STILL_OK, 414 LOCKDEP_NOW_UNRELIABLE 415 }; 416 extern void add_taint(unsigned flag, enum lockdep_ok); 417 extern int test_taint(unsigned flag); 418 extern unsigned long get_taint(void); 419 extern int root_mountflags; 420 421 extern bool early_boot_irqs_disabled; 422 423 /* 424 * Values used for system_state. Ordering of the states must not be changed 425 * as code checks for <, <=, >, >= STATE. 426 */ 427 extern enum system_states { 428 SYSTEM_BOOTING, 429 SYSTEM_SCHEDULING, 430 SYSTEM_RUNNING, 431 SYSTEM_HALT, 432 SYSTEM_POWER_OFF, 433 SYSTEM_RESTART, 434 SYSTEM_SUSPEND, 435 } system_state; 436 437 /* This cannot be an enum because some may be used in assembly source. */ 438 #define TAINT_PROPRIETARY_MODULE 0 439 #define TAINT_FORCED_MODULE 1 440 #define TAINT_CPU_OUT_OF_SPEC 2 441 #define TAINT_FORCED_RMMOD 3 442 #define TAINT_MACHINE_CHECK 4 443 #define TAINT_BAD_PAGE 5 444 #define TAINT_USER 6 445 #define TAINT_DIE 7 446 #define TAINT_OVERRIDDEN_ACPI_TABLE 8 447 #define TAINT_WARN 9 448 #define TAINT_CRAP 10 449 #define TAINT_FIRMWARE_WORKAROUND 11 450 #define TAINT_OOT_MODULE 12 451 #define TAINT_UNSIGNED_MODULE 13 452 #define TAINT_SOFTLOCKUP 14 453 #define TAINT_LIVEPATCH 15 454 #define TAINT_AUX 16 455 #define TAINT_RANDSTRUCT 17 456 #define TAINT_FLAGS_COUNT 18 457 #define TAINT_FLAGS_MAX ((1UL << TAINT_FLAGS_COUNT) - 1) 458 459 struct taint_flag { 460 char c_true; /* character printed when tainted */ 461 char c_false; /* character printed when not tainted */ 462 bool module; /* also show as a per-module taint flag */ 463 }; 464 465 extern const struct taint_flag taint_flags[TAINT_FLAGS_COUNT]; 466 467 extern const char hex_asc[]; 468 #define hex_asc_lo(x) hex_asc[((x) & 0x0f)] 469 #define hex_asc_hi(x) hex_asc[((x) & 0xf0) >> 4] 470 471 static inline char *hex_byte_pack(char *buf, u8 byte) 472 { 473 *buf++ = hex_asc_hi(byte); 474 *buf++ = hex_asc_lo(byte); 475 return buf; 476 } 477 478 extern const char hex_asc_upper[]; 479 #define hex_asc_upper_lo(x) hex_asc_upper[((x) & 0x0f)] 480 #define hex_asc_upper_hi(x) hex_asc_upper[((x) & 0xf0) >> 4] 481 482 static inline char *hex_byte_pack_upper(char *buf, u8 byte) 483 { 484 *buf++ = hex_asc_upper_hi(byte); 485 *buf++ = hex_asc_upper_lo(byte); 486 return buf; 487 } 488 489 extern int hex_to_bin(char ch); 490 extern int __must_check hex2bin(u8 *dst, const char *src, size_t count); 491 extern char *bin2hex(char *dst, const void *src, size_t count); 492 493 bool mac_pton(const char *s, u8 *mac); 494 495 /* 496 * General tracing related utility functions - trace_printk(), 497 * tracing_on/tracing_off and tracing_start()/tracing_stop 498 * 499 * Use tracing_on/tracing_off when you want to quickly turn on or off 500 * tracing. It simply enables or disables the recording of the trace events. 501 * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on 502 * file, which gives a means for the kernel and userspace to interact. 503 * Place a tracing_off() in the kernel where you want tracing to end. 504 * From user space, examine the trace, and then echo 1 > tracing_on 505 * to continue tracing. 506 * 507 * tracing_stop/tracing_start has slightly more overhead. It is used 508 * by things like suspend to ram where disabling the recording of the 509 * trace is not enough, but tracing must actually stop because things 510 * like calling smp_processor_id() may crash the system. 511 * 512 * Most likely, you want to use tracing_on/tracing_off. 513 */ 514 515 enum ftrace_dump_mode { 516 DUMP_NONE, 517 DUMP_ALL, 518 DUMP_ORIG, 519 }; 520 521 #ifdef CONFIG_TRACING 522 void tracing_on(void); 523 void tracing_off(void); 524 int tracing_is_on(void); 525 void tracing_snapshot(void); 526 void tracing_snapshot_alloc(void); 527 528 extern void tracing_start(void); 529 extern void tracing_stop(void); 530 531 static inline __printf(1, 2) 532 void ____trace_printk_check_format(const char *fmt, ...) 533 { 534 } 535 #define __trace_printk_check_format(fmt, args...) \ 536 do { \ 537 if (0) \ 538 ____trace_printk_check_format(fmt, ##args); \ 539 } while (0) 540 541 /** 542 * trace_printk - printf formatting in the ftrace buffer 543 * @fmt: the printf format for printing 544 * 545 * Note: __trace_printk is an internal function for trace_printk() and 546 * the @ip is passed in via the trace_printk() macro. 547 * 548 * This function allows a kernel developer to debug fast path sections 549 * that printk is not appropriate for. By scattering in various 550 * printk like tracing in the code, a developer can quickly see 551 * where problems are occurring. 552 * 553 * This is intended as a debugging tool for the developer only. 554 * Please refrain from leaving trace_printks scattered around in 555 * your code. (Extra memory is used for special buffers that are 556 * allocated when trace_printk() is used.) 557 * 558 * A little optimization trick is done here. If there's only one 559 * argument, there's no need to scan the string for printf formats. 560 * The trace_puts() will suffice. But how can we take advantage of 561 * using trace_puts() when trace_printk() has only one argument? 562 * By stringifying the args and checking the size we can tell 563 * whether or not there are args. __stringify((__VA_ARGS__)) will 564 * turn into "()\0" with a size of 3 when there are no args, anything 565 * else will be bigger. All we need to do is define a string to this, 566 * and then take its size and compare to 3. If it's bigger, use 567 * do_trace_printk() otherwise, optimize it to trace_puts(). Then just 568 * let gcc optimize the rest. 569 */ 570 571 #define trace_printk(fmt, ...) \ 572 do { \ 573 char _______STR[] = __stringify((__VA_ARGS__)); \ 574 if (sizeof(_______STR) > 3) \ 575 do_trace_printk(fmt, ##__VA_ARGS__); \ 576 else \ 577 trace_puts(fmt); \ 578 } while (0) 579 580 #define do_trace_printk(fmt, args...) \ 581 do { \ 582 static const char *trace_printk_fmt __used \ 583 __section("__trace_printk_fmt") = \ 584 __builtin_constant_p(fmt) ? fmt : NULL; \ 585 \ 586 __trace_printk_check_format(fmt, ##args); \ 587 \ 588 if (__builtin_constant_p(fmt)) \ 589 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \ 590 else \ 591 __trace_printk(_THIS_IP_, fmt, ##args); \ 592 } while (0) 593 594 extern __printf(2, 3) 595 int __trace_bprintk(unsigned long ip, const char *fmt, ...); 596 597 extern __printf(2, 3) 598 int __trace_printk(unsigned long ip, const char *fmt, ...); 599 600 /** 601 * trace_puts - write a string into the ftrace buffer 602 * @str: the string to record 603 * 604 * Note: __trace_bputs is an internal function for trace_puts and 605 * the @ip is passed in via the trace_puts macro. 606 * 607 * This is similar to trace_printk() but is made for those really fast 608 * paths that a developer wants the least amount of "Heisenbug" effects, 609 * where the processing of the print format is still too much. 610 * 611 * This function allows a kernel developer to debug fast path sections 612 * that printk is not appropriate for. By scattering in various 613 * printk like tracing in the code, a developer can quickly see 614 * where problems are occurring. 615 * 616 * This is intended as a debugging tool for the developer only. 617 * Please refrain from leaving trace_puts scattered around in 618 * your code. (Extra memory is used for special buffers that are 619 * allocated when trace_puts() is used.) 620 * 621 * Returns: 0 if nothing was written, positive # if string was. 622 * (1 when __trace_bputs is used, strlen(str) when __trace_puts is used) 623 */ 624 625 #define trace_puts(str) ({ \ 626 static const char *trace_printk_fmt __used \ 627 __section("__trace_printk_fmt") = \ 628 __builtin_constant_p(str) ? str : NULL; \ 629 \ 630 if (__builtin_constant_p(str)) \ 631 __trace_bputs(_THIS_IP_, trace_printk_fmt); \ 632 else \ 633 __trace_puts(_THIS_IP_, str, strlen(str)); \ 634 }) 635 extern int __trace_bputs(unsigned long ip, const char *str); 636 extern int __trace_puts(unsigned long ip, const char *str, int size); 637 638 extern void trace_dump_stack(int skip); 639 640 /* 641 * The double __builtin_constant_p is because gcc will give us an error 642 * if we try to allocate the static variable to fmt if it is not a 643 * constant. Even with the outer if statement. 644 */ 645 #define ftrace_vprintk(fmt, vargs) \ 646 do { \ 647 if (__builtin_constant_p(fmt)) { \ 648 static const char *trace_printk_fmt __used \ 649 __section("__trace_printk_fmt") = \ 650 __builtin_constant_p(fmt) ? fmt : NULL; \ 651 \ 652 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs); \ 653 } else \ 654 __ftrace_vprintk(_THIS_IP_, fmt, vargs); \ 655 } while (0) 656 657 extern __printf(2, 0) int 658 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap); 659 660 extern __printf(2, 0) int 661 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap); 662 663 extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode); 664 #else 665 static inline void tracing_start(void) { } 666 static inline void tracing_stop(void) { } 667 static inline void trace_dump_stack(int skip) { } 668 669 static inline void tracing_on(void) { } 670 static inline void tracing_off(void) { } 671 static inline int tracing_is_on(void) { return 0; } 672 static inline void tracing_snapshot(void) { } 673 static inline void tracing_snapshot_alloc(void) { } 674 675 static inline __printf(1, 2) 676 int trace_printk(const char *fmt, ...) 677 { 678 return 0; 679 } 680 static __printf(1, 0) inline int 681 ftrace_vprintk(const char *fmt, va_list ap) 682 { 683 return 0; 684 } 685 static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { } 686 #endif /* CONFIG_TRACING */ 687 688 /* This counts to 12. Any more, it will return 13th argument. */ 689 #define __COUNT_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _n, X...) _n 690 #define COUNT_ARGS(X...) __COUNT_ARGS(, ##X, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0) 691 692 #define __CONCAT(a, b) a ## b 693 #define CONCATENATE(a, b) __CONCAT(a, b) 694 695 /** 696 * container_of - cast a member of a structure out to the containing structure 697 * @ptr: the pointer to the member. 698 * @type: the type of the container struct this is embedded in. 699 * @member: the name of the member within the struct. 700 * 701 */ 702 #define container_of(ptr, type, member) ({ \ 703 void *__mptr = (void *)(ptr); \ 704 BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \ 705 !__same_type(*(ptr), void), \ 706 "pointer type mismatch in container_of()"); \ 707 ((type *)(__mptr - offsetof(type, member))); }) 708 709 /** 710 * container_of_safe - cast a member of a structure out to the containing structure 711 * @ptr: the pointer to the member. 712 * @type: the type of the container struct this is embedded in. 713 * @member: the name of the member within the struct. 714 * 715 * If IS_ERR_OR_NULL(ptr), ptr is returned unchanged. 716 */ 717 #define container_of_safe(ptr, type, member) ({ \ 718 void *__mptr = (void *)(ptr); \ 719 BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \ 720 !__same_type(*(ptr), void), \ 721 "pointer type mismatch in container_of()"); \ 722 IS_ERR_OR_NULL(__mptr) ? ERR_CAST(__mptr) : \ 723 ((type *)(__mptr - offsetof(type, member))); }) 724 725 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */ 726 #ifdef CONFIG_FTRACE_MCOUNT_RECORD 727 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD 728 #endif 729 730 /* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */ 731 #define VERIFY_OCTAL_PERMISSIONS(perms) \ 732 (BUILD_BUG_ON_ZERO((perms) < 0) + \ 733 BUILD_BUG_ON_ZERO((perms) > 0777) + \ 734 /* USER_READABLE >= GROUP_READABLE >= OTHER_READABLE */ \ 735 BUILD_BUG_ON_ZERO((((perms) >> 6) & 4) < (((perms) >> 3) & 4)) + \ 736 BUILD_BUG_ON_ZERO((((perms) >> 3) & 4) < ((perms) & 4)) + \ 737 /* USER_WRITABLE >= GROUP_WRITABLE */ \ 738 BUILD_BUG_ON_ZERO((((perms) >> 6) & 2) < (((perms) >> 3) & 2)) + \ 739 /* OTHER_WRITABLE? Generally considered a bad idea. */ \ 740 BUILD_BUG_ON_ZERO((perms) & 2) + \ 741 (perms)) 742 #endif 743