1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * NOTE: 4 * 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. 10 */ 11 #ifndef _LINUX_KERNEL_H 12 #define _LINUX_KERNEL_H 13 14 #include <linux/stdarg.h> 15 #include <linux/align.h> 16 #include <linux/array_size.h> 17 #include <linux/limits.h> 18 #include <linux/linkage.h> 19 #include <linux/stddef.h> 20 #include <linux/types.h> 21 #include <linux/compiler.h> 22 #include <linux/container_of.h> 23 #include <linux/bitops.h> 24 #include <linux/hex.h> 25 #include <linux/kstrtox.h> 26 #include <linux/log2.h> 27 #include <linux/math.h> 28 #include <linux/minmax.h> 29 #include <linux/typecheck.h> 30 #include <linux/panic.h> 31 #include <linux/printk.h> 32 #include <linux/build_bug.h> 33 #include <linux/sprintf.h> 34 #include <linux/static_call_types.h> 35 #include <linux/instruction_pointer.h> 36 #include <linux/wordpart.h> 37 38 #include <asm/byteorder.h> 39 40 #include <uapi/linux/kernel.h> 41 42 #define STACK_MAGIC 0xdeadbeef 43 44 /* generic data direction definitions */ 45 #define READ 0 46 #define WRITE 1 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 struct completion; 58 struct user; 59 60 #ifdef CONFIG_PREEMPT_VOLUNTARY_BUILD 61 62 extern int __cond_resched(void); 63 # define might_resched() __cond_resched() 64 65 #elif defined(CONFIG_PREEMPT_DYNAMIC) && defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL) 66 67 extern int __cond_resched(void); 68 69 DECLARE_STATIC_CALL(might_resched, __cond_resched); 70 might_resched(void)71 static __always_inline void might_resched(void) 72 { 73 static_call_mod(might_resched)(); 74 } 75 76 #elif defined(CONFIG_PREEMPT_DYNAMIC) && defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY) 77 78 extern int dynamic_might_resched(void); 79 # define might_resched() dynamic_might_resched() 80 81 #else 82 83 # define might_resched() do { } while (0) 84 85 #endif /* CONFIG_PREEMPT_* */ 86 87 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP 88 extern void __might_resched(const char *file, int line, unsigned int offsets); 89 extern void __might_sleep(const char *file, int line); 90 extern void __cant_sleep(const char *file, int line, int preempt_offset); 91 extern void __cant_migrate(const char *file, int line); 92 93 /** 94 * might_sleep - annotation for functions that can sleep 95 * 96 * this macro will print a stack trace if it is executed in an atomic 97 * context (spinlock, irq-handler, ...). Additional sections where blocking is 98 * not allowed can be annotated with non_block_start() and non_block_end() 99 * pairs. 100 * 101 * This is a useful debugging help to be able to catch problems early and not 102 * be bitten later when the calling function happens to sleep when it is not 103 * supposed to. 104 */ 105 # define might_sleep() \ 106 do { __might_sleep(__FILE__, __LINE__); might_resched(); } while (0) 107 /** 108 * cant_sleep - annotation for functions that cannot sleep 109 * 110 * this macro will print a stack trace if it is executed with preemption enabled 111 */ 112 # define cant_sleep() \ 113 do { __cant_sleep(__FILE__, __LINE__, 0); } while (0) 114 # define sched_annotate_sleep() (current->task_state_change = 0) 115 116 /** 117 * cant_migrate - annotation for functions that cannot migrate 118 * 119 * Will print a stack trace if executed in code which is migratable 120 */ 121 # define cant_migrate() \ 122 do { \ 123 if (IS_ENABLED(CONFIG_SMP)) \ 124 __cant_migrate(__FILE__, __LINE__); \ 125 } while (0) 126 127 /** 128 * non_block_start - annotate the start of section where sleeping is prohibited 129 * 130 * This is on behalf of the oom reaper, specifically when it is calling the mmu 131 * notifiers. The problem is that if the notifier were to block on, for example, 132 * mutex_lock() and if the process which holds that mutex were to perform a 133 * sleeping memory allocation, the oom reaper is now blocked on completion of 134 * that memory allocation. Other blocking calls like wait_event() pose similar 135 * issues. 136 */ 137 # define non_block_start() (current->non_block_count++) 138 /** 139 * non_block_end - annotate the end of section where sleeping is prohibited 140 * 141 * Closes a section opened by non_block_start(). 142 */ 143 # define non_block_end() WARN_ON(current->non_block_count-- == 0) 144 #else __might_resched(const char * file,int line,unsigned int offsets)145 static inline void __might_resched(const char *file, int line, 146 unsigned int offsets) { } __might_sleep(const char * file,int line)147 static inline void __might_sleep(const char *file, int line) { } 148 # define might_sleep() do { might_resched(); } while (0) 149 # define cant_sleep() do { } while (0) 150 # define cant_migrate() do { } while (0) 151 # define sched_annotate_sleep() do { } while (0) 152 # define non_block_start() do { } while (0) 153 # define non_block_end() do { } while (0) 154 #endif 155 156 #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0) 157 158 #if defined(CONFIG_MMU) && \ 159 (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP)) 160 #define might_fault() __might_fault(__FILE__, __LINE__) 161 void __might_fault(const char *file, int line); 162 #else might_fault(void)163 static inline void might_fault(void) { } 164 #endif 165 166 void do_exit(long error_code) __noreturn; 167 168 extern int core_kernel_text(unsigned long addr); 169 extern int __kernel_text_address(unsigned long addr); 170 extern int kernel_text_address(unsigned long addr); 171 extern int func_ptr_is_kernel_text(void *ptr); 172 173 extern void bust_spinlocks(int yes); 174 175 extern int root_mountflags; 176 177 extern bool early_boot_irqs_disabled; 178 179 /* 180 * Values used for system_state. Ordering of the states must not be changed 181 * as code checks for <, <=, >, >= STATE. 182 */ 183 extern enum system_states { 184 SYSTEM_BOOTING, 185 SYSTEM_SCHEDULING, 186 SYSTEM_FREEING_INITMEM, 187 SYSTEM_RUNNING, 188 SYSTEM_HALT, 189 SYSTEM_POWER_OFF, 190 SYSTEM_RESTART, 191 SYSTEM_SUSPEND, 192 } system_state; 193 194 /* 195 * General tracing related utility functions - trace_printk(), 196 * tracing_on/tracing_off and tracing_start()/tracing_stop 197 * 198 * Use tracing_on/tracing_off when you want to quickly turn on or off 199 * tracing. It simply enables or disables the recording of the trace events. 200 * This also corresponds to the user space /sys/kernel/tracing/tracing_on 201 * file, which gives a means for the kernel and userspace to interact. 202 * Place a tracing_off() in the kernel where you want tracing to end. 203 * From user space, examine the trace, and then echo 1 > tracing_on 204 * to continue tracing. 205 * 206 * tracing_stop/tracing_start has slightly more overhead. It is used 207 * by things like suspend to ram where disabling the recording of the 208 * trace is not enough, but tracing must actually stop because things 209 * like calling smp_processor_id() may crash the system. 210 * 211 * Most likely, you want to use tracing_on/tracing_off. 212 */ 213 214 enum ftrace_dump_mode { 215 DUMP_NONE, 216 DUMP_ALL, 217 DUMP_ORIG, 218 DUMP_PARAM, 219 }; 220 221 #ifdef CONFIG_TRACING 222 void tracing_on(void); 223 void tracing_off(void); 224 int tracing_is_on(void); 225 void tracing_snapshot(void); 226 void tracing_snapshot_alloc(void); 227 228 extern void tracing_start(void); 229 extern void tracing_stop(void); 230 231 static inline __printf(1, 2) ____trace_printk_check_format(const char * fmt,...)232 void ____trace_printk_check_format(const char *fmt, ...) 233 { 234 } 235 #define __trace_printk_check_format(fmt, args...) \ 236 do { \ 237 if (0) \ 238 ____trace_printk_check_format(fmt, ##args); \ 239 } while (0) 240 241 /** 242 * trace_printk - printf formatting in the ftrace buffer 243 * @fmt: the printf format for printing 244 * 245 * Note: __trace_printk is an internal function for trace_printk() and 246 * the @ip is passed in via the trace_printk() macro. 247 * 248 * This function allows a kernel developer to debug fast path sections 249 * that printk is not appropriate for. By scattering in various 250 * printk like tracing in the code, a developer can quickly see 251 * where problems are occurring. 252 * 253 * This is intended as a debugging tool for the developer only. 254 * Please refrain from leaving trace_printks scattered around in 255 * your code. (Extra memory is used for special buffers that are 256 * allocated when trace_printk() is used.) 257 * 258 * A little optimization trick is done here. If there's only one 259 * argument, there's no need to scan the string for printf formats. 260 * The trace_puts() will suffice. But how can we take advantage of 261 * using trace_puts() when trace_printk() has only one argument? 262 * By stringifying the args and checking the size we can tell 263 * whether or not there are args. __stringify((__VA_ARGS__)) will 264 * turn into "()\0" with a size of 3 when there are no args, anything 265 * else will be bigger. All we need to do is define a string to this, 266 * and then take its size and compare to 3. If it's bigger, use 267 * do_trace_printk() otherwise, optimize it to trace_puts(). Then just 268 * let gcc optimize the rest. 269 */ 270 271 #define trace_printk(fmt, ...) \ 272 do { \ 273 char _______STR[] = __stringify((__VA_ARGS__)); \ 274 if (sizeof(_______STR) > 3) \ 275 do_trace_printk(fmt, ##__VA_ARGS__); \ 276 else \ 277 trace_puts(fmt); \ 278 } while (0) 279 280 #define do_trace_printk(fmt, args...) \ 281 do { \ 282 static const char *trace_printk_fmt __used \ 283 __section("__trace_printk_fmt") = \ 284 __builtin_constant_p(fmt) ? fmt : NULL; \ 285 \ 286 __trace_printk_check_format(fmt, ##args); \ 287 \ 288 if (__builtin_constant_p(fmt)) \ 289 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \ 290 else \ 291 __trace_printk(_THIS_IP_, fmt, ##args); \ 292 } while (0) 293 294 extern __printf(2, 3) 295 int __trace_bprintk(unsigned long ip, const char *fmt, ...); 296 297 extern __printf(2, 3) 298 int __trace_printk(unsigned long ip, const char *fmt, ...); 299 300 /** 301 * trace_puts - write a string into the ftrace buffer 302 * @str: the string to record 303 * 304 * Note: __trace_bputs is an internal function for trace_puts and 305 * the @ip is passed in via the trace_puts macro. 306 * 307 * This is similar to trace_printk() but is made for those really fast 308 * paths that a developer wants the least amount of "Heisenbug" effects, 309 * where the processing of the print format is still too much. 310 * 311 * This function allows a kernel developer to debug fast path sections 312 * that printk is not appropriate for. By scattering in various 313 * printk like tracing in the code, a developer can quickly see 314 * where problems are occurring. 315 * 316 * This is intended as a debugging tool for the developer only. 317 * Please refrain from leaving trace_puts scattered around in 318 * your code. (Extra memory is used for special buffers that are 319 * allocated when trace_puts() is used.) 320 * 321 * Returns: 0 if nothing was written, positive # if string was. 322 * (1 when __trace_bputs is used, strlen(str) when __trace_puts is used) 323 */ 324 325 #define trace_puts(str) ({ \ 326 static const char *trace_printk_fmt __used \ 327 __section("__trace_printk_fmt") = \ 328 __builtin_constant_p(str) ? str : NULL; \ 329 \ 330 if (__builtin_constant_p(str)) \ 331 __trace_bputs(_THIS_IP_, trace_printk_fmt); \ 332 else \ 333 __trace_puts(_THIS_IP_, str, strlen(str)); \ 334 }) 335 extern int __trace_bputs(unsigned long ip, const char *str); 336 extern int __trace_puts(unsigned long ip, const char *str, int size); 337 338 extern void trace_dump_stack(int skip); 339 340 /* 341 * The double __builtin_constant_p is because gcc will give us an error 342 * if we try to allocate the static variable to fmt if it is not a 343 * constant. Even with the outer if statement. 344 */ 345 #define ftrace_vprintk(fmt, vargs) \ 346 do { \ 347 if (__builtin_constant_p(fmt)) { \ 348 static const char *trace_printk_fmt __used \ 349 __section("__trace_printk_fmt") = \ 350 __builtin_constant_p(fmt) ? fmt : NULL; \ 351 \ 352 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs); \ 353 } else \ 354 __ftrace_vprintk(_THIS_IP_, fmt, vargs); \ 355 } while (0) 356 357 extern __printf(2, 0) int 358 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap); 359 360 extern __printf(2, 0) int 361 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap); 362 363 extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode); 364 #else tracing_start(void)365 static inline void tracing_start(void) { } tracing_stop(void)366 static inline void tracing_stop(void) { } trace_dump_stack(int skip)367 static inline void trace_dump_stack(int skip) { } 368 tracing_on(void)369 static inline void tracing_on(void) { } tracing_off(void)370 static inline void tracing_off(void) { } tracing_is_on(void)371 static inline int tracing_is_on(void) { return 0; } tracing_snapshot(void)372 static inline void tracing_snapshot(void) { } tracing_snapshot_alloc(void)373 static inline void tracing_snapshot_alloc(void) { } 374 375 static inline __printf(1, 2) trace_printk(const char * fmt,...)376 int trace_printk(const char *fmt, ...) 377 { 378 return 0; 379 } 380 static __printf(1, 0) inline int ftrace_vprintk(const char * fmt,va_list ap)381 ftrace_vprintk(const char *fmt, va_list ap) 382 { 383 return 0; 384 } ftrace_dump(enum ftrace_dump_mode oops_dump_mode)385 static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { } 386 #endif /* CONFIG_TRACING */ 387 388 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */ 389 #ifdef CONFIG_FTRACE_MCOUNT_RECORD 390 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD 391 #endif 392 393 /* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */ 394 #define VERIFY_OCTAL_PERMISSIONS(perms) \ 395 (BUILD_BUG_ON_ZERO((perms) < 0) + \ 396 BUILD_BUG_ON_ZERO((perms) > 0777) + \ 397 /* USER_READABLE >= GROUP_READABLE >= OTHER_READABLE */ \ 398 BUILD_BUG_ON_ZERO((((perms) >> 6) & 4) < (((perms) >> 3) & 4)) + \ 399 BUILD_BUG_ON_ZERO((((perms) >> 3) & 4) < ((perms) & 4)) + \ 400 /* USER_WRITABLE >= GROUP_WRITABLE */ \ 401 BUILD_BUG_ON_ZERO((((perms) >> 6) & 2) < (((perms) >> 3) & 2)) + \ 402 /* OTHER_WRITABLE? Generally considered a bad idea. */ \ 403 BUILD_BUG_ON_ZERO((perms) & 2) + \ 404 (perms)) 405 #endif 406