1 /* 2 * Ftrace header. For implementation details beyond the random comments 3 * scattered below, see: Documentation/trace/ftrace-design.txt 4 */ 5 6 #ifndef _LINUX_FTRACE_H 7 #define _LINUX_FTRACE_H 8 9 #include <linux/trace_clock.h> 10 #include <linux/kallsyms.h> 11 #include <linux/linkage.h> 12 #include <linux/bitops.h> 13 #include <linux/ptrace.h> 14 #include <linux/ktime.h> 15 #include <linux/sched.h> 16 #include <linux/types.h> 17 #include <linux/init.h> 18 #include <linux/fs.h> 19 20 #include <asm/ftrace.h> 21 22 /* 23 * If the arch supports passing the variable contents of 24 * function_trace_op as the third parameter back from the 25 * mcount call, then the arch should define this as 1. 26 */ 27 #ifndef ARCH_SUPPORTS_FTRACE_OPS 28 #define ARCH_SUPPORTS_FTRACE_OPS 0 29 #endif 30 31 /* 32 * If the arch's mcount caller does not support all of ftrace's 33 * features, then it must call an indirect function that 34 * does. Or at least does enough to prevent any unwelcomed side effects. 35 */ 36 #if !ARCH_SUPPORTS_FTRACE_OPS 37 # define FTRACE_FORCE_LIST_FUNC 1 38 #else 39 # define FTRACE_FORCE_LIST_FUNC 0 40 #endif 41 42 /* Main tracing buffer and events set up */ 43 #ifdef CONFIG_TRACING 44 void trace_init(void); 45 void early_trace_init(void); 46 #else 47 static inline void trace_init(void) { } 48 static inline void early_trace_init(void) { } 49 #endif 50 51 struct module; 52 struct ftrace_hash; 53 54 #ifdef CONFIG_FUNCTION_TRACER 55 56 extern int ftrace_enabled; 57 extern int 58 ftrace_enable_sysctl(struct ctl_table *table, int write, 59 void __user *buffer, size_t *lenp, 60 loff_t *ppos); 61 62 struct ftrace_ops; 63 64 typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip, 65 struct ftrace_ops *op, struct pt_regs *regs); 66 67 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops); 68 69 /* 70 * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are 71 * set in the flags member. 72 * CONTROL, SAVE_REGS, SAVE_REGS_IF_SUPPORTED, RECURSION_SAFE, STUB and 73 * IPMODIFY are a kind of attribute flags which can be set only before 74 * registering the ftrace_ops, and can not be modified while registered. 75 * Changing those attribute flags after registering ftrace_ops will 76 * cause unexpected results. 77 * 78 * ENABLED - set/unset when ftrace_ops is registered/unregistered 79 * DYNAMIC - set when ftrace_ops is registered to denote dynamically 80 * allocated ftrace_ops which need special care 81 * PER_CPU - set manualy by ftrace_ops user to denote the ftrace_ops 82 * could be controlled by following calls: 83 * ftrace_function_local_enable 84 * ftrace_function_local_disable 85 * SAVE_REGS - The ftrace_ops wants regs saved at each function called 86 * and passed to the callback. If this flag is set, but the 87 * architecture does not support passing regs 88 * (CONFIG_DYNAMIC_FTRACE_WITH_REGS is not defined), then the 89 * ftrace_ops will fail to register, unless the next flag 90 * is set. 91 * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the 92 * handler can handle an arch that does not save regs 93 * (the handler tests if regs == NULL), then it can set 94 * this flag instead. It will not fail registering the ftrace_ops 95 * but, the regs field will be NULL if the arch does not support 96 * passing regs to the handler. 97 * Note, if this flag is set, the SAVE_REGS flag will automatically 98 * get set upon registering the ftrace_ops, if the arch supports it. 99 * RECURSION_SAFE - The ftrace_ops can set this to tell the ftrace infrastructure 100 * that the call back has its own recursion protection. If it does 101 * not set this, then the ftrace infrastructure will add recursion 102 * protection for the caller. 103 * STUB - The ftrace_ops is just a place holder. 104 * INITIALIZED - The ftrace_ops has already been initialized (first use time 105 * register_ftrace_function() is called, it will initialized the ops) 106 * DELETED - The ops are being deleted, do not let them be registered again. 107 * ADDING - The ops is in the process of being added. 108 * REMOVING - The ops is in the process of being removed. 109 * MODIFYING - The ops is in the process of changing its filter functions. 110 * ALLOC_TRAMP - A dynamic trampoline was allocated by the core code. 111 * The arch specific code sets this flag when it allocated a 112 * trampoline. This lets the arch know that it can update the 113 * trampoline in case the callback function changes. 114 * The ftrace_ops trampoline can be set by the ftrace users, and 115 * in such cases the arch must not modify it. Only the arch ftrace 116 * core code should set this flag. 117 * IPMODIFY - The ops can modify the IP register. This can only be set with 118 * SAVE_REGS. If another ops with this flag set is already registered 119 * for any of the functions that this ops will be registered for, then 120 * this ops will fail to register or set_filter_ip. 121 * PID - Is affected by set_ftrace_pid (allows filtering on those pids) 122 * RCU - Set when the ops can only be called when RCU is watching. 123 * TRACE_ARRAY - The ops->private points to a trace_array descriptor. 124 */ 125 enum { 126 FTRACE_OPS_FL_ENABLED = 1 << 0, 127 FTRACE_OPS_FL_DYNAMIC = 1 << 1, 128 FTRACE_OPS_FL_PER_CPU = 1 << 2, 129 FTRACE_OPS_FL_SAVE_REGS = 1 << 3, 130 FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED = 1 << 4, 131 FTRACE_OPS_FL_RECURSION_SAFE = 1 << 5, 132 FTRACE_OPS_FL_STUB = 1 << 6, 133 FTRACE_OPS_FL_INITIALIZED = 1 << 7, 134 FTRACE_OPS_FL_DELETED = 1 << 8, 135 FTRACE_OPS_FL_ADDING = 1 << 9, 136 FTRACE_OPS_FL_REMOVING = 1 << 10, 137 FTRACE_OPS_FL_MODIFYING = 1 << 11, 138 FTRACE_OPS_FL_ALLOC_TRAMP = 1 << 12, 139 FTRACE_OPS_FL_IPMODIFY = 1 << 13, 140 FTRACE_OPS_FL_PID = 1 << 14, 141 FTRACE_OPS_FL_RCU = 1 << 15, 142 FTRACE_OPS_FL_TRACE_ARRAY = 1 << 16, 143 }; 144 145 #ifdef CONFIG_DYNAMIC_FTRACE 146 /* The hash used to know what functions callbacks trace */ 147 struct ftrace_ops_hash { 148 struct ftrace_hash __rcu *notrace_hash; 149 struct ftrace_hash __rcu *filter_hash; 150 struct mutex regex_lock; 151 }; 152 153 void ftrace_free_init_mem(void); 154 #else 155 static inline void ftrace_free_init_mem(void) { } 156 #endif 157 158 /* 159 * Note, ftrace_ops can be referenced outside of RCU protection, unless 160 * the RCU flag is set. If ftrace_ops is allocated and not part of kernel 161 * core data, the unregistering of it will perform a scheduling on all CPUs 162 * to make sure that there are no more users. Depending on the load of the 163 * system that may take a bit of time. 164 * 165 * Any private data added must also take care not to be freed and if private 166 * data is added to a ftrace_ops that is in core code, the user of the 167 * ftrace_ops must perform a schedule_on_each_cpu() before freeing it. 168 */ 169 struct ftrace_ops { 170 ftrace_func_t func; 171 struct ftrace_ops __rcu *next; 172 unsigned long flags; 173 void *private; 174 ftrace_func_t saved_func; 175 int __percpu *disabled; 176 #ifdef CONFIG_DYNAMIC_FTRACE 177 struct ftrace_ops_hash local_hash; 178 struct ftrace_ops_hash *func_hash; 179 struct ftrace_ops_hash old_hash; 180 unsigned long trampoline; 181 unsigned long trampoline_size; 182 #endif 183 }; 184 185 /* 186 * Type of the current tracing. 187 */ 188 enum ftrace_tracing_type_t { 189 FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */ 190 FTRACE_TYPE_RETURN, /* Hook the return of the function */ 191 }; 192 193 /* Current tracing type, default is FTRACE_TYPE_ENTER */ 194 extern enum ftrace_tracing_type_t ftrace_tracing_type; 195 196 /* 197 * The ftrace_ops must be a static and should also 198 * be read_mostly. These functions do modify read_mostly variables 199 * so use them sparely. Never free an ftrace_op or modify the 200 * next pointer after it has been registered. Even after unregistering 201 * it, the next pointer may still be used internally. 202 */ 203 int register_ftrace_function(struct ftrace_ops *ops); 204 int unregister_ftrace_function(struct ftrace_ops *ops); 205 void clear_ftrace_function(void); 206 207 /** 208 * ftrace_function_local_enable - enable ftrace_ops on current cpu 209 * 210 * This function enables tracing on current cpu by decreasing 211 * the per cpu control variable. 212 * It must be called with preemption disabled and only on ftrace_ops 213 * registered with FTRACE_OPS_FL_PER_CPU. If called without preemption 214 * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled. 215 */ 216 static inline void ftrace_function_local_enable(struct ftrace_ops *ops) 217 { 218 if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU))) 219 return; 220 221 (*this_cpu_ptr(ops->disabled))--; 222 } 223 224 /** 225 * ftrace_function_local_disable - disable ftrace_ops on current cpu 226 * 227 * This function disables tracing on current cpu by increasing 228 * the per cpu control variable. 229 * It must be called with preemption disabled and only on ftrace_ops 230 * registered with FTRACE_OPS_FL_PER_CPU. If called without preemption 231 * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled. 232 */ 233 static inline void ftrace_function_local_disable(struct ftrace_ops *ops) 234 { 235 if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU))) 236 return; 237 238 (*this_cpu_ptr(ops->disabled))++; 239 } 240 241 /** 242 * ftrace_function_local_disabled - returns ftrace_ops disabled value 243 * on current cpu 244 * 245 * This function returns value of ftrace_ops::disabled on current cpu. 246 * It must be called with preemption disabled and only on ftrace_ops 247 * registered with FTRACE_OPS_FL_PER_CPU. If called without preemption 248 * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled. 249 */ 250 static inline int ftrace_function_local_disabled(struct ftrace_ops *ops) 251 { 252 WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU)); 253 return *this_cpu_ptr(ops->disabled); 254 } 255 256 extern void ftrace_stub(unsigned long a0, unsigned long a1, 257 struct ftrace_ops *op, struct pt_regs *regs); 258 259 #else /* !CONFIG_FUNCTION_TRACER */ 260 /* 261 * (un)register_ftrace_function must be a macro since the ops parameter 262 * must not be evaluated. 263 */ 264 #define register_ftrace_function(ops) ({ 0; }) 265 #define unregister_ftrace_function(ops) ({ 0; }) 266 static inline int ftrace_nr_registered_ops(void) 267 { 268 return 0; 269 } 270 static inline void clear_ftrace_function(void) { } 271 static inline void ftrace_kill(void) { } 272 static inline void ftrace_free_init_mem(void) { } 273 #endif /* CONFIG_FUNCTION_TRACER */ 274 275 #ifdef CONFIG_STACK_TRACER 276 277 #define STACK_TRACE_ENTRIES 500 278 279 struct stack_trace; 280 281 extern unsigned stack_trace_index[]; 282 extern struct stack_trace stack_trace_max; 283 extern unsigned long stack_trace_max_size; 284 extern arch_spinlock_t stack_trace_max_lock; 285 286 extern int stack_tracer_enabled; 287 void stack_trace_print(void); 288 int 289 stack_trace_sysctl(struct ctl_table *table, int write, 290 void __user *buffer, size_t *lenp, 291 loff_t *ppos); 292 293 /* DO NOT MODIFY THIS VARIABLE DIRECTLY! */ 294 DECLARE_PER_CPU(int, disable_stack_tracer); 295 296 /** 297 * stack_tracer_disable - temporarily disable the stack tracer 298 * 299 * There's a few locations (namely in RCU) where stack tracing 300 * cannot be executed. This function is used to disable stack 301 * tracing during those critical sections. 302 * 303 * This function must be called with preemption or interrupts 304 * disabled and stack_tracer_enable() must be called shortly after 305 * while preemption or interrupts are still disabled. 306 */ 307 static inline void stack_tracer_disable(void) 308 { 309 /* Preemption or interupts must be disabled */ 310 if (IS_ENABLED(CONFIG_PREEMPT_DEBUG)) 311 WARN_ON_ONCE(!preempt_count() || !irqs_disabled()); 312 this_cpu_inc(disable_stack_tracer); 313 } 314 315 /** 316 * stack_tracer_enable - re-enable the stack tracer 317 * 318 * After stack_tracer_disable() is called, stack_tracer_enable() 319 * must be called shortly afterward. 320 */ 321 static inline void stack_tracer_enable(void) 322 { 323 if (IS_ENABLED(CONFIG_PREEMPT_DEBUG)) 324 WARN_ON_ONCE(!preempt_count() || !irqs_disabled()); 325 this_cpu_dec(disable_stack_tracer); 326 } 327 #else 328 static inline void stack_tracer_disable(void) { } 329 static inline void stack_tracer_enable(void) { } 330 #endif 331 332 #ifdef CONFIG_DYNAMIC_FTRACE 333 334 int ftrace_arch_code_modify_prepare(void); 335 int ftrace_arch_code_modify_post_process(void); 336 337 struct dyn_ftrace; 338 339 enum ftrace_bug_type { 340 FTRACE_BUG_UNKNOWN, 341 FTRACE_BUG_INIT, 342 FTRACE_BUG_NOP, 343 FTRACE_BUG_CALL, 344 FTRACE_BUG_UPDATE, 345 }; 346 extern enum ftrace_bug_type ftrace_bug_type; 347 348 /* 349 * Archs can set this to point to a variable that holds the value that was 350 * expected at the call site before calling ftrace_bug(). 351 */ 352 extern const void *ftrace_expected; 353 354 void ftrace_bug(int err, struct dyn_ftrace *rec); 355 356 struct seq_file; 357 358 extern int ftrace_text_reserved(const void *start, const void *end); 359 360 extern int ftrace_nr_registered_ops(void); 361 362 bool is_ftrace_trampoline(unsigned long addr); 363 364 /* 365 * The dyn_ftrace record's flags field is split into two parts. 366 * the first part which is '0-FTRACE_REF_MAX' is a counter of 367 * the number of callbacks that have registered the function that 368 * the dyn_ftrace descriptor represents. 369 * 370 * The second part is a mask: 371 * ENABLED - the function is being traced 372 * REGS - the record wants the function to save regs 373 * REGS_EN - the function is set up to save regs. 374 * IPMODIFY - the record allows for the IP address to be changed. 375 * DISABLED - the record is not ready to be touched yet 376 * 377 * When a new ftrace_ops is registered and wants a function to save 378 * pt_regs, the rec->flag REGS is set. When the function has been 379 * set up to save regs, the REG_EN flag is set. Once a function 380 * starts saving regs it will do so until all ftrace_ops are removed 381 * from tracing that function. 382 */ 383 enum { 384 FTRACE_FL_ENABLED = (1UL << 31), 385 FTRACE_FL_REGS = (1UL << 30), 386 FTRACE_FL_REGS_EN = (1UL << 29), 387 FTRACE_FL_TRAMP = (1UL << 28), 388 FTRACE_FL_TRAMP_EN = (1UL << 27), 389 FTRACE_FL_IPMODIFY = (1UL << 26), 390 FTRACE_FL_DISABLED = (1UL << 25), 391 }; 392 393 #define FTRACE_REF_MAX_SHIFT 25 394 #define FTRACE_FL_BITS 7 395 #define FTRACE_FL_MASKED_BITS ((1UL << FTRACE_FL_BITS) - 1) 396 #define FTRACE_FL_MASK (FTRACE_FL_MASKED_BITS << FTRACE_REF_MAX_SHIFT) 397 #define FTRACE_REF_MAX ((1UL << FTRACE_REF_MAX_SHIFT) - 1) 398 399 #define ftrace_rec_count(rec) ((rec)->flags & ~FTRACE_FL_MASK) 400 401 struct dyn_ftrace { 402 unsigned long ip; /* address of mcount call-site */ 403 unsigned long flags; 404 struct dyn_arch_ftrace arch; 405 }; 406 407 int ftrace_force_update(void); 408 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip, 409 int remove, int reset); 410 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf, 411 int len, int reset); 412 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf, 413 int len, int reset); 414 void ftrace_set_global_filter(unsigned char *buf, int len, int reset); 415 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset); 416 void ftrace_free_filter(struct ftrace_ops *ops); 417 void ftrace_ops_set_global_filter(struct ftrace_ops *ops); 418 419 enum { 420 FTRACE_UPDATE_CALLS = (1 << 0), 421 FTRACE_DISABLE_CALLS = (1 << 1), 422 FTRACE_UPDATE_TRACE_FUNC = (1 << 2), 423 FTRACE_START_FUNC_RET = (1 << 3), 424 FTRACE_STOP_FUNC_RET = (1 << 4), 425 }; 426 427 /* 428 * The FTRACE_UPDATE_* enum is used to pass information back 429 * from the ftrace_update_record() and ftrace_test_record() 430 * functions. These are called by the code update routines 431 * to find out what is to be done for a given function. 432 * 433 * IGNORE - The function is already what we want it to be 434 * MAKE_CALL - Start tracing the function 435 * MODIFY_CALL - Stop saving regs for the function 436 * MAKE_NOP - Stop tracing the function 437 */ 438 enum { 439 FTRACE_UPDATE_IGNORE, 440 FTRACE_UPDATE_MAKE_CALL, 441 FTRACE_UPDATE_MODIFY_CALL, 442 FTRACE_UPDATE_MAKE_NOP, 443 }; 444 445 enum { 446 FTRACE_ITER_FILTER = (1 << 0), 447 FTRACE_ITER_NOTRACE = (1 << 1), 448 FTRACE_ITER_PRINTALL = (1 << 2), 449 FTRACE_ITER_DO_PROBES = (1 << 3), 450 FTRACE_ITER_PROBE = (1 << 4), 451 FTRACE_ITER_MOD = (1 << 5), 452 FTRACE_ITER_ENABLED = (1 << 6), 453 }; 454 455 void arch_ftrace_update_code(int command); 456 457 struct ftrace_rec_iter; 458 459 struct ftrace_rec_iter *ftrace_rec_iter_start(void); 460 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter); 461 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter); 462 463 #define for_ftrace_rec_iter(iter) \ 464 for (iter = ftrace_rec_iter_start(); \ 465 iter; \ 466 iter = ftrace_rec_iter_next(iter)) 467 468 469 int ftrace_update_record(struct dyn_ftrace *rec, int enable); 470 int ftrace_test_record(struct dyn_ftrace *rec, int enable); 471 void ftrace_run_stop_machine(int command); 472 unsigned long ftrace_location(unsigned long ip); 473 unsigned long ftrace_location_range(unsigned long start, unsigned long end); 474 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec); 475 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec); 476 477 extern ftrace_func_t ftrace_trace_function; 478 479 int ftrace_regex_open(struct ftrace_ops *ops, int flag, 480 struct inode *inode, struct file *file); 481 ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf, 482 size_t cnt, loff_t *ppos); 483 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf, 484 size_t cnt, loff_t *ppos); 485 int ftrace_regex_release(struct inode *inode, struct file *file); 486 487 void __init 488 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable); 489 490 /* defined in arch */ 491 extern int ftrace_ip_converted(unsigned long ip); 492 extern int ftrace_dyn_arch_init(void); 493 extern void ftrace_replace_code(int enable); 494 extern int ftrace_update_ftrace_func(ftrace_func_t func); 495 extern void ftrace_caller(void); 496 extern void ftrace_regs_caller(void); 497 extern void ftrace_call(void); 498 extern void ftrace_regs_call(void); 499 extern void mcount_call(void); 500 501 void ftrace_modify_all_code(int command); 502 503 #ifndef FTRACE_ADDR 504 #define FTRACE_ADDR ((unsigned long)ftrace_caller) 505 #endif 506 507 #ifndef FTRACE_GRAPH_ADDR 508 #define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller) 509 #endif 510 511 #ifndef FTRACE_REGS_ADDR 512 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS 513 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller) 514 #else 515 # define FTRACE_REGS_ADDR FTRACE_ADDR 516 #endif 517 #endif 518 519 /* 520 * If an arch would like functions that are only traced 521 * by the function graph tracer to jump directly to its own 522 * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR 523 * to be that address to jump to. 524 */ 525 #ifndef FTRACE_GRAPH_TRAMP_ADDR 526 #define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0) 527 #endif 528 529 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 530 extern void ftrace_graph_caller(void); 531 extern int ftrace_enable_ftrace_graph_caller(void); 532 extern int ftrace_disable_ftrace_graph_caller(void); 533 #else 534 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; } 535 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; } 536 #endif 537 538 /** 539 * ftrace_make_nop - convert code into nop 540 * @mod: module structure if called by module load initialization 541 * @rec: the mcount call site record 542 * @addr: the address that the call site should be calling 543 * 544 * This is a very sensitive operation and great care needs 545 * to be taken by the arch. The operation should carefully 546 * read the location, check to see if what is read is indeed 547 * what we expect it to be, and then on success of the compare, 548 * it should write to the location. 549 * 550 * The code segment at @rec->ip should be a caller to @addr 551 * 552 * Return must be: 553 * 0 on success 554 * -EFAULT on error reading the location 555 * -EINVAL on a failed compare of the contents 556 * -EPERM on error writing to the location 557 * Any other value will be considered a failure. 558 */ 559 extern int ftrace_make_nop(struct module *mod, 560 struct dyn_ftrace *rec, unsigned long addr); 561 562 /** 563 * ftrace_make_call - convert a nop call site into a call to addr 564 * @rec: the mcount call site record 565 * @addr: the address that the call site should call 566 * 567 * This is a very sensitive operation and great care needs 568 * to be taken by the arch. The operation should carefully 569 * read the location, check to see if what is read is indeed 570 * what we expect it to be, and then on success of the compare, 571 * it should write to the location. 572 * 573 * The code segment at @rec->ip should be a nop 574 * 575 * Return must be: 576 * 0 on success 577 * -EFAULT on error reading the location 578 * -EINVAL on a failed compare of the contents 579 * -EPERM on error writing to the location 580 * Any other value will be considered a failure. 581 */ 582 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr); 583 584 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS 585 /** 586 * ftrace_modify_call - convert from one addr to another (no nop) 587 * @rec: the mcount call site record 588 * @old_addr: the address expected to be currently called to 589 * @addr: the address to change to 590 * 591 * This is a very sensitive operation and great care needs 592 * to be taken by the arch. The operation should carefully 593 * read the location, check to see if what is read is indeed 594 * what we expect it to be, and then on success of the compare, 595 * it should write to the location. 596 * 597 * The code segment at @rec->ip should be a caller to @old_addr 598 * 599 * Return must be: 600 * 0 on success 601 * -EFAULT on error reading the location 602 * -EINVAL on a failed compare of the contents 603 * -EPERM on error writing to the location 604 * Any other value will be considered a failure. 605 */ 606 extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, 607 unsigned long addr); 608 #else 609 /* Should never be called */ 610 static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, 611 unsigned long addr) 612 { 613 return -EINVAL; 614 } 615 #endif 616 617 /* May be defined in arch */ 618 extern int ftrace_arch_read_dyn_info(char *buf, int size); 619 620 extern int skip_trace(unsigned long ip); 621 extern void ftrace_module_init(struct module *mod); 622 extern void ftrace_module_enable(struct module *mod); 623 extern void ftrace_release_mod(struct module *mod); 624 625 extern void ftrace_disable_daemon(void); 626 extern void ftrace_enable_daemon(void); 627 #else /* CONFIG_DYNAMIC_FTRACE */ 628 static inline int skip_trace(unsigned long ip) { return 0; } 629 static inline int ftrace_force_update(void) { return 0; } 630 static inline void ftrace_disable_daemon(void) { } 631 static inline void ftrace_enable_daemon(void) { } 632 static inline void ftrace_module_init(struct module *mod) { } 633 static inline void ftrace_module_enable(struct module *mod) { } 634 static inline void ftrace_release_mod(struct module *mod) { } 635 static inline int ftrace_text_reserved(const void *start, const void *end) 636 { 637 return 0; 638 } 639 static inline unsigned long ftrace_location(unsigned long ip) 640 { 641 return 0; 642 } 643 644 /* 645 * Again users of functions that have ftrace_ops may not 646 * have them defined when ftrace is not enabled, but these 647 * functions may still be called. Use a macro instead of inline. 648 */ 649 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; }) 650 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0) 651 #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; }) 652 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; }) 653 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; }) 654 #define ftrace_free_filter(ops) do { } while (0) 655 #define ftrace_ops_set_global_filter(ops) do { } while (0) 656 657 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf, 658 size_t cnt, loff_t *ppos) { return -ENODEV; } 659 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf, 660 size_t cnt, loff_t *ppos) { return -ENODEV; } 661 static inline int 662 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; } 663 664 static inline bool is_ftrace_trampoline(unsigned long addr) 665 { 666 return false; 667 } 668 #endif /* CONFIG_DYNAMIC_FTRACE */ 669 670 /* totally disable ftrace - can not re-enable after this */ 671 void ftrace_kill(void); 672 673 static inline void tracer_disable(void) 674 { 675 #ifdef CONFIG_FUNCTION_TRACER 676 ftrace_enabled = 0; 677 #endif 678 } 679 680 /* 681 * Ftrace disable/restore without lock. Some synchronization mechanism 682 * must be used to prevent ftrace_enabled to be changed between 683 * disable/restore. 684 */ 685 static inline int __ftrace_enabled_save(void) 686 { 687 #ifdef CONFIG_FUNCTION_TRACER 688 int saved_ftrace_enabled = ftrace_enabled; 689 ftrace_enabled = 0; 690 return saved_ftrace_enabled; 691 #else 692 return 0; 693 #endif 694 } 695 696 static inline void __ftrace_enabled_restore(int enabled) 697 { 698 #ifdef CONFIG_FUNCTION_TRACER 699 ftrace_enabled = enabled; 700 #endif 701 } 702 703 /* All archs should have this, but we define it for consistency */ 704 #ifndef ftrace_return_address0 705 # define ftrace_return_address0 __builtin_return_address(0) 706 #endif 707 708 /* Archs may use other ways for ADDR1 and beyond */ 709 #ifndef ftrace_return_address 710 # ifdef CONFIG_FRAME_POINTER 711 # define ftrace_return_address(n) __builtin_return_address(n) 712 # else 713 # define ftrace_return_address(n) 0UL 714 # endif 715 #endif 716 717 #define CALLER_ADDR0 ((unsigned long)ftrace_return_address0) 718 #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1)) 719 #define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2)) 720 #define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3)) 721 #define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4)) 722 #define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5)) 723 #define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6)) 724 725 static inline unsigned long get_lock_parent_ip(void) 726 { 727 unsigned long addr = CALLER_ADDR0; 728 729 if (!in_lock_functions(addr)) 730 return addr; 731 addr = CALLER_ADDR1; 732 if (!in_lock_functions(addr)) 733 return addr; 734 return CALLER_ADDR2; 735 } 736 737 #ifdef CONFIG_IRQSOFF_TRACER 738 extern void time_hardirqs_on(unsigned long a0, unsigned long a1); 739 extern void time_hardirqs_off(unsigned long a0, unsigned long a1); 740 #else 741 static inline void time_hardirqs_on(unsigned long a0, unsigned long a1) { } 742 static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { } 743 #endif 744 745 #ifdef CONFIG_PREEMPT_TRACER 746 extern void trace_preempt_on(unsigned long a0, unsigned long a1); 747 extern void trace_preempt_off(unsigned long a0, unsigned long a1); 748 #else 749 /* 750 * Use defines instead of static inlines because some arches will make code out 751 * of the CALLER_ADDR, when we really want these to be a real nop. 752 */ 753 # define trace_preempt_on(a0, a1) do { } while (0) 754 # define trace_preempt_off(a0, a1) do { } while (0) 755 #endif 756 757 #ifdef CONFIG_FTRACE_MCOUNT_RECORD 758 extern void ftrace_init(void); 759 #else 760 static inline void ftrace_init(void) { } 761 #endif 762 763 /* 764 * Structure that defines an entry function trace. 765 * It's already packed but the attribute "packed" is needed 766 * to remove extra padding at the end. 767 */ 768 struct ftrace_graph_ent { 769 unsigned long func; /* Current function */ 770 int depth; 771 } __packed; 772 773 /* 774 * Structure that defines a return function trace. 775 * It's already packed but the attribute "packed" is needed 776 * to remove extra padding at the end. 777 */ 778 struct ftrace_graph_ret { 779 unsigned long func; /* Current function */ 780 /* Number of functions that overran the depth limit for current task */ 781 unsigned long overrun; 782 unsigned long long calltime; 783 unsigned long long rettime; 784 int depth; 785 } __packed; 786 787 /* Type of the callback handlers for tracing function graph*/ 788 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */ 789 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */ 790 791 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 792 793 /* for init task */ 794 #define INIT_FTRACE_GRAPH .ret_stack = NULL, 795 796 /* 797 * Stack of return addresses for functions 798 * of a thread. 799 * Used in struct thread_info 800 */ 801 struct ftrace_ret_stack { 802 unsigned long ret; 803 unsigned long func; 804 unsigned long long calltime; 805 #ifdef CONFIG_FUNCTION_PROFILER 806 unsigned long long subtime; 807 #endif 808 #ifdef HAVE_FUNCTION_GRAPH_FP_TEST 809 unsigned long fp; 810 #endif 811 #ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR 812 unsigned long *retp; 813 #endif 814 }; 815 816 /* 817 * Primary handler of a function return. 818 * It relays on ftrace_return_to_handler. 819 * Defined in entry_32/64.S 820 */ 821 extern void return_to_handler(void); 822 823 extern int 824 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth, 825 unsigned long frame_pointer, unsigned long *retp); 826 827 unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx, 828 unsigned long ret, unsigned long *retp); 829 830 /* 831 * Sometimes we don't want to trace a function with the function 832 * graph tracer but we want them to keep traced by the usual function 833 * tracer if the function graph tracer is not configured. 834 */ 835 #define __notrace_funcgraph notrace 836 837 #define FTRACE_NOTRACE_DEPTH 65536 838 #define FTRACE_RETFUNC_DEPTH 50 839 #define FTRACE_RETSTACK_ALLOC_SIZE 32 840 extern int register_ftrace_graph(trace_func_graph_ret_t retfunc, 841 trace_func_graph_ent_t entryfunc); 842 843 extern bool ftrace_graph_is_dead(void); 844 extern void ftrace_graph_stop(void); 845 846 /* The current handlers in use */ 847 extern trace_func_graph_ret_t ftrace_graph_return; 848 extern trace_func_graph_ent_t ftrace_graph_entry; 849 850 extern void unregister_ftrace_graph(void); 851 852 extern void ftrace_graph_init_task(struct task_struct *t); 853 extern void ftrace_graph_exit_task(struct task_struct *t); 854 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu); 855 856 static inline int task_curr_ret_stack(struct task_struct *t) 857 { 858 return t->curr_ret_stack; 859 } 860 861 static inline void pause_graph_tracing(void) 862 { 863 atomic_inc(¤t->tracing_graph_pause); 864 } 865 866 static inline void unpause_graph_tracing(void) 867 { 868 atomic_dec(¤t->tracing_graph_pause); 869 } 870 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */ 871 872 #define __notrace_funcgraph 873 #define INIT_FTRACE_GRAPH 874 875 static inline void ftrace_graph_init_task(struct task_struct *t) { } 876 static inline void ftrace_graph_exit_task(struct task_struct *t) { } 877 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { } 878 879 static inline int register_ftrace_graph(trace_func_graph_ret_t retfunc, 880 trace_func_graph_ent_t entryfunc) 881 { 882 return -1; 883 } 884 static inline void unregister_ftrace_graph(void) { } 885 886 static inline int task_curr_ret_stack(struct task_struct *tsk) 887 { 888 return -1; 889 } 890 891 static inline unsigned long 892 ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret, 893 unsigned long *retp) 894 { 895 return ret; 896 } 897 898 static inline void pause_graph_tracing(void) { } 899 static inline void unpause_graph_tracing(void) { } 900 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 901 902 #ifdef CONFIG_TRACING 903 904 /* flags for current->trace */ 905 enum { 906 TSK_TRACE_FL_TRACE_BIT = 0, 907 TSK_TRACE_FL_GRAPH_BIT = 1, 908 }; 909 enum { 910 TSK_TRACE_FL_TRACE = 1 << TSK_TRACE_FL_TRACE_BIT, 911 TSK_TRACE_FL_GRAPH = 1 << TSK_TRACE_FL_GRAPH_BIT, 912 }; 913 914 static inline void set_tsk_trace_trace(struct task_struct *tsk) 915 { 916 set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace); 917 } 918 919 static inline void clear_tsk_trace_trace(struct task_struct *tsk) 920 { 921 clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace); 922 } 923 924 static inline int test_tsk_trace_trace(struct task_struct *tsk) 925 { 926 return tsk->trace & TSK_TRACE_FL_TRACE; 927 } 928 929 static inline void set_tsk_trace_graph(struct task_struct *tsk) 930 { 931 set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace); 932 } 933 934 static inline void clear_tsk_trace_graph(struct task_struct *tsk) 935 { 936 clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace); 937 } 938 939 static inline int test_tsk_trace_graph(struct task_struct *tsk) 940 { 941 return tsk->trace & TSK_TRACE_FL_GRAPH; 942 } 943 944 enum ftrace_dump_mode; 945 946 extern enum ftrace_dump_mode ftrace_dump_on_oops; 947 extern int tracepoint_printk; 948 949 extern void disable_trace_on_warning(void); 950 extern int __disable_trace_on_warning; 951 952 #ifdef CONFIG_PREEMPT 953 #define INIT_TRACE_RECURSION .trace_recursion = 0, 954 #endif 955 956 int tracepoint_printk_sysctl(struct ctl_table *table, int write, 957 void __user *buffer, size_t *lenp, 958 loff_t *ppos); 959 960 #else /* CONFIG_TRACING */ 961 static inline void disable_trace_on_warning(void) { } 962 #endif /* CONFIG_TRACING */ 963 964 #ifndef INIT_TRACE_RECURSION 965 #define INIT_TRACE_RECURSION 966 #endif 967 968 #ifdef CONFIG_FTRACE_SYSCALLS 969 970 unsigned long arch_syscall_addr(int nr); 971 972 #endif /* CONFIG_FTRACE_SYSCALLS */ 973 974 #endif /* _LINUX_FTRACE_H */ 975