1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * Ftrace header. For implementation details beyond the random comments 4 * scattered below, see: Documentation/trace/ftrace-design.rst 5 */ 6 7 #ifndef _LINUX_FTRACE_H 8 #define _LINUX_FTRACE_H 9 10 #include <linux/trace_recursion.h> 11 #include <linux/trace_clock.h> 12 #include <linux/jump_label.h> 13 #include <linux/kallsyms.h> 14 #include <linux/linkage.h> 15 #include <linux/bitops.h> 16 #include <linux/ptrace.h> 17 #include <linux/ktime.h> 18 #include <linux/sched.h> 19 #include <linux/types.h> 20 #include <linux/init.h> 21 #include <linux/fs.h> 22 23 #include <asm/ftrace.h> 24 25 /* 26 * If the arch supports passing the variable contents of 27 * function_trace_op as the third parameter back from the 28 * mcount call, then the arch should define this as 1. 29 */ 30 #ifndef ARCH_SUPPORTS_FTRACE_OPS 31 #define ARCH_SUPPORTS_FTRACE_OPS 0 32 #endif 33 34 #ifdef CONFIG_TRACER_SNAPSHOT 35 extern void ftrace_boot_snapshot(void); 36 #else 37 static inline void ftrace_boot_snapshot(void) { } 38 #endif 39 40 struct ftrace_ops; 41 struct ftrace_regs; 42 struct dyn_ftrace; 43 44 char *arch_ftrace_match_adjust(char *str, const char *search); 45 46 #ifdef CONFIG_HAVE_FUNCTION_GRAPH_FREGS 47 unsigned long ftrace_return_to_handler(struct ftrace_regs *fregs); 48 #else 49 unsigned long ftrace_return_to_handler(unsigned long frame_pointer); 50 #endif 51 52 #ifdef CONFIG_FUNCTION_TRACER 53 /* 54 * If the arch's mcount caller does not support all of ftrace's 55 * features, then it must call an indirect function that 56 * does. Or at least does enough to prevent any unwelcome side effects. 57 * 58 * Also define the function prototype that these architectures use 59 * to call the ftrace_ops_list_func(). 60 */ 61 #if !ARCH_SUPPORTS_FTRACE_OPS 62 # define FTRACE_FORCE_LIST_FUNC 1 63 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip); 64 #else 65 # define FTRACE_FORCE_LIST_FUNC 0 66 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, 67 struct ftrace_ops *op, struct ftrace_regs *fregs); 68 #endif 69 extern const struct ftrace_ops ftrace_nop_ops; 70 extern const struct ftrace_ops ftrace_list_ops; 71 struct ftrace_ops *ftrace_find_unique_ops(struct dyn_ftrace *rec); 72 #endif /* CONFIG_FUNCTION_TRACER */ 73 74 /* Main tracing buffer and events set up */ 75 #ifdef CONFIG_TRACING 76 void trace_init(void); 77 void early_trace_init(void); 78 #else 79 static inline void trace_init(void) { } 80 static inline void early_trace_init(void) { } 81 #endif 82 83 struct module; 84 struct ftrace_hash; 85 struct ftrace_func_entry; 86 87 #if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_MODULES) && \ 88 defined(CONFIG_DYNAMIC_FTRACE) 89 int 90 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size, 91 unsigned long *off, char **modname, 92 const unsigned char **modbuildid, char *sym); 93 #else 94 static inline int 95 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size, 96 unsigned long *off, char **modname, 97 const unsigned char **modbuildid, char *sym) 98 { 99 return 0; 100 } 101 #endif 102 103 #if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_DYNAMIC_FTRACE) 104 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value, 105 char *type, char *name, 106 char *module_name, int *exported); 107 #else 108 static inline int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value, 109 char *type, char *name, 110 char *module_name, int *exported) 111 { 112 return -1; 113 } 114 #endif 115 116 #ifdef CONFIG_FUNCTION_TRACER 117 118 #include <linux/ftrace_regs.h> 119 120 extern int ftrace_enabled; 121 122 /** 123 * ftrace_regs - ftrace partial/optimal register set 124 * 125 * ftrace_regs represents a group of registers which is used at the 126 * function entry and exit. There are three types of registers. 127 * 128 * - Registers for passing the parameters to callee, including the stack 129 * pointer. (e.g. rcx, rdx, rdi, rsi, r8, r9 and rsp on x86_64) 130 * - Registers for passing the return values to caller. 131 * (e.g. rax and rdx on x86_64) 132 * - Registers for hooking the function call and return including the 133 * frame pointer (the frame pointer is architecture/config dependent) 134 * (e.g. rip, rbp and rsp for x86_64) 135 * 136 * Also, architecture dependent fields can be used for internal process. 137 * (e.g. orig_ax on x86_64) 138 * 139 * Basically, ftrace_regs stores the registers related to the context. 140 * On function entry, registers for function parameters and hooking the 141 * function call are stored, and on function exit, registers for function 142 * return value and frame pointers are stored. 143 * 144 * And also, it dpends on the context that which registers are restored 145 * from the ftrace_regs. 146 * On the function entry, those registers will be restored except for 147 * the stack pointer, so that user can change the function parameters 148 * and instruction pointer (e.g. live patching.) 149 * On the function exit, only registers which is used for return values 150 * are restored. 151 * 152 * NOTE: user *must not* access regs directly, only do it via APIs, because 153 * the member can be changed according to the architecture. 154 * This is why the structure is empty here, so that nothing accesses 155 * the ftrace_regs directly. 156 */ 157 struct ftrace_regs { 158 /* Nothing to see here, use the accessor functions! */ 159 }; 160 161 #define ftrace_regs_size() sizeof(struct __arch_ftrace_regs) 162 163 #ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS 164 /* 165 * Architectures that define HAVE_DYNAMIC_FTRACE_WITH_ARGS must define their own 166 * arch_ftrace_get_regs() where it only returns pt_regs *if* it is fully 167 * populated. It should return NULL otherwise. 168 */ 169 static inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs *fregs) 170 { 171 return &arch_ftrace_regs(fregs)->regs; 172 } 173 174 /* 175 * ftrace_regs_set_instruction_pointer() is to be defined by the architecture 176 * if to allow setting of the instruction pointer from the ftrace_regs when 177 * HAVE_DYNAMIC_FTRACE_WITH_ARGS is set and it supports live kernel patching. 178 */ 179 #define ftrace_regs_set_instruction_pointer(fregs, ip) do { } while (0) 180 #endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */ 181 182 #ifdef CONFIG_HAVE_FTRACE_REGS_HAVING_PT_REGS 183 184 static_assert(sizeof(struct pt_regs) == ftrace_regs_size()); 185 186 #endif /* CONFIG_HAVE_FTRACE_REGS_HAVING_PT_REGS */ 187 188 static __always_inline struct pt_regs *ftrace_get_regs(struct ftrace_regs *fregs) 189 { 190 if (!fregs) 191 return NULL; 192 193 return arch_ftrace_get_regs(fregs); 194 } 195 196 #if !defined(CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS) || \ 197 defined(CONFIG_HAVE_FTRACE_REGS_HAVING_PT_REGS) 198 199 #ifndef arch_ftrace_partial_regs 200 #define arch_ftrace_partial_regs(regs) do {} while (0) 201 #endif 202 203 static __always_inline struct pt_regs * 204 ftrace_partial_regs(struct ftrace_regs *fregs, struct pt_regs *regs) 205 { 206 /* 207 * If CONFIG_HAVE_FTRACE_REGS_HAVING_PT_REGS=y, ftrace_regs memory 208 * layout is including pt_regs. So always returns that address. 209 * Since arch_ftrace_get_regs() will check some members and may return 210 * NULL, we can not use it. 211 */ 212 regs = &arch_ftrace_regs(fregs)->regs; 213 214 /* Allow arch specific updates to regs. */ 215 arch_ftrace_partial_regs(regs); 216 return regs; 217 } 218 219 #endif /* !CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS || CONFIG_HAVE_FTRACE_REGS_HAVING_PT_REGS */ 220 221 #ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS 222 223 /* 224 * Please define arch dependent pt_regs which compatible to the 225 * perf_arch_fetch_caller_regs() but based on ftrace_regs. 226 * This requires 227 * - user_mode(_regs) returns false (always kernel mode). 228 * - able to use the _regs for stack trace. 229 */ 230 #ifndef arch_ftrace_fill_perf_regs 231 /* As same as perf_arch_fetch_caller_regs(), do nothing by default */ 232 #define arch_ftrace_fill_perf_regs(fregs, _regs) do {} while (0) 233 #endif 234 235 static __always_inline struct pt_regs * 236 ftrace_fill_perf_regs(struct ftrace_regs *fregs, struct pt_regs *regs) 237 { 238 arch_ftrace_fill_perf_regs(fregs, regs); 239 return regs; 240 } 241 242 #else /* !CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */ 243 244 static __always_inline struct pt_regs * 245 ftrace_fill_perf_regs(struct ftrace_regs *fregs, struct pt_regs *regs) 246 { 247 return &arch_ftrace_regs(fregs)->regs; 248 } 249 250 #endif 251 252 /* 253 * When true, the ftrace_regs_{get,set}_*() functions may be used on fregs. 254 * Note: this can be true even when ftrace_get_regs() cannot provide a pt_regs. 255 */ 256 static __always_inline bool ftrace_regs_has_args(struct ftrace_regs *fregs) 257 { 258 if (IS_ENABLED(CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS)) 259 return true; 260 261 return ftrace_get_regs(fregs) != NULL; 262 } 263 264 #ifdef CONFIG_HAVE_REGS_AND_STACK_ACCESS_API 265 static __always_inline unsigned long 266 ftrace_regs_get_kernel_stack_nth(struct ftrace_regs *fregs, unsigned int nth) 267 { 268 unsigned long *stackp; 269 270 stackp = (unsigned long *)ftrace_regs_get_stack_pointer(fregs); 271 if (((unsigned long)(stackp + nth) & ~(THREAD_SIZE - 1)) == 272 ((unsigned long)stackp & ~(THREAD_SIZE - 1))) 273 return *(stackp + nth); 274 275 return 0; 276 } 277 #else /* !CONFIG_HAVE_REGS_AND_STACK_ACCESS_API */ 278 #define ftrace_regs_get_kernel_stack_nth(fregs, nth) (0L) 279 #endif /* CONFIG_HAVE_REGS_AND_STACK_ACCESS_API */ 280 281 typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip, 282 struct ftrace_ops *op, struct ftrace_regs *fregs); 283 284 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops); 285 286 /* 287 * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are 288 * set in the flags member. 289 * CONTROL, SAVE_REGS, SAVE_REGS_IF_SUPPORTED, RECURSION, STUB and 290 * IPMODIFY are a kind of attribute flags which can be set only before 291 * registering the ftrace_ops, and can not be modified while registered. 292 * Changing those attribute flags after registering ftrace_ops will 293 * cause unexpected results. 294 * 295 * ENABLED - set/unset when ftrace_ops is registered/unregistered 296 * DYNAMIC - set when ftrace_ops is registered to denote dynamically 297 * allocated ftrace_ops which need special care 298 * SAVE_REGS - The ftrace_ops wants regs saved at each function called 299 * and passed to the callback. If this flag is set, but the 300 * architecture does not support passing regs 301 * (CONFIG_DYNAMIC_FTRACE_WITH_REGS is not defined), then the 302 * ftrace_ops will fail to register, unless the next flag 303 * is set. 304 * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the 305 * handler can handle an arch that does not save regs 306 * (the handler tests if regs == NULL), then it can set 307 * this flag instead. It will not fail registering the ftrace_ops 308 * but, the regs field will be NULL if the arch does not support 309 * passing regs to the handler. 310 * Note, if this flag is set, the SAVE_REGS flag will automatically 311 * get set upon registering the ftrace_ops, if the arch supports it. 312 * RECURSION - The ftrace_ops can set this to tell the ftrace infrastructure 313 * that the call back needs recursion protection. If it does 314 * not set this, then the ftrace infrastructure will assume 315 * that the callback can handle recursion on its own. 316 * STUB - The ftrace_ops is just a place holder. 317 * INITIALIZED - The ftrace_ops has already been initialized (first use time 318 * register_ftrace_function() is called, it will initialized the ops) 319 * DELETED - The ops are being deleted, do not let them be registered again. 320 * ADDING - The ops is in the process of being added. 321 * REMOVING - The ops is in the process of being removed. 322 * MODIFYING - The ops is in the process of changing its filter functions. 323 * ALLOC_TRAMP - A dynamic trampoline was allocated by the core code. 324 * The arch specific code sets this flag when it allocated a 325 * trampoline. This lets the arch know that it can update the 326 * trampoline in case the callback function changes. 327 * The ftrace_ops trampoline can be set by the ftrace users, and 328 * in such cases the arch must not modify it. Only the arch ftrace 329 * core code should set this flag. 330 * IPMODIFY - The ops can modify the IP register. This can only be set with 331 * SAVE_REGS. If another ops with this flag set is already registered 332 * for any of the functions that this ops will be registered for, then 333 * this ops will fail to register or set_filter_ip. 334 * PID - Is affected by set_ftrace_pid (allows filtering on those pids) 335 * RCU - Set when the ops can only be called when RCU is watching. 336 * TRACE_ARRAY - The ops->private points to a trace_array descriptor. 337 * PERMANENT - Set when the ops is permanent and should not be affected by 338 * ftrace_enabled. 339 * DIRECT - Used by the direct ftrace_ops helper for direct functions 340 * (internal ftrace only, should not be used by others) 341 * SUBOP - Is controlled by another op in field managed. 342 * GRAPH - Is a component of the fgraph_ops structure 343 */ 344 enum { 345 FTRACE_OPS_FL_ENABLED = BIT(0), 346 FTRACE_OPS_FL_DYNAMIC = BIT(1), 347 FTRACE_OPS_FL_SAVE_REGS = BIT(2), 348 FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED = BIT(3), 349 FTRACE_OPS_FL_RECURSION = BIT(4), 350 FTRACE_OPS_FL_STUB = BIT(5), 351 FTRACE_OPS_FL_INITIALIZED = BIT(6), 352 FTRACE_OPS_FL_DELETED = BIT(7), 353 FTRACE_OPS_FL_ADDING = BIT(8), 354 FTRACE_OPS_FL_REMOVING = BIT(9), 355 FTRACE_OPS_FL_MODIFYING = BIT(10), 356 FTRACE_OPS_FL_ALLOC_TRAMP = BIT(11), 357 FTRACE_OPS_FL_IPMODIFY = BIT(12), 358 FTRACE_OPS_FL_PID = BIT(13), 359 FTRACE_OPS_FL_RCU = BIT(14), 360 FTRACE_OPS_FL_TRACE_ARRAY = BIT(15), 361 FTRACE_OPS_FL_PERMANENT = BIT(16), 362 FTRACE_OPS_FL_DIRECT = BIT(17), 363 FTRACE_OPS_FL_SUBOP = BIT(18), 364 FTRACE_OPS_FL_GRAPH = BIT(19), 365 }; 366 367 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_ARGS 368 #define FTRACE_OPS_FL_SAVE_ARGS FTRACE_OPS_FL_SAVE_REGS 369 #else 370 #define FTRACE_OPS_FL_SAVE_ARGS 0 371 #endif 372 373 /* 374 * FTRACE_OPS_CMD_* commands allow the ftrace core logic to request changes 375 * to a ftrace_ops. Note, the requests may fail. 376 * 377 * ENABLE_SHARE_IPMODIFY_SELF - enable a DIRECT ops to work on the same 378 * function as an ops with IPMODIFY. Called 379 * when the DIRECT ops is being registered. 380 * This is called with both direct_mutex and 381 * ftrace_lock are locked. 382 * 383 * ENABLE_SHARE_IPMODIFY_PEER - enable a DIRECT ops to work on the same 384 * function as an ops with IPMODIFY. Called 385 * when the other ops (the one with IPMODIFY) 386 * is being registered. 387 * This is called with direct_mutex locked. 388 * 389 * DISABLE_SHARE_IPMODIFY_PEER - disable a DIRECT ops to work on the same 390 * function as an ops with IPMODIFY. Called 391 * when the other ops (the one with IPMODIFY) 392 * is being unregistered. 393 * This is called with direct_mutex locked. 394 */ 395 enum ftrace_ops_cmd { 396 FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF, 397 FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER, 398 FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER, 399 }; 400 401 /* 402 * For most ftrace_ops_cmd, 403 * Returns: 404 * 0 - Success. 405 * Negative on failure. The return value is dependent on the 406 * callback. 407 */ 408 typedef int (*ftrace_ops_func_t)(struct ftrace_ops *op, unsigned long ip, enum ftrace_ops_cmd cmd); 409 410 #ifdef CONFIG_DYNAMIC_FTRACE 411 412 #define FTRACE_HASH_DEFAULT_BITS 10 413 414 struct ftrace_hash *alloc_ftrace_hash(int size_bits); 415 void free_ftrace_hash(struct ftrace_hash *hash); 416 struct ftrace_func_entry *add_ftrace_hash_entry_direct(struct ftrace_hash *hash, 417 unsigned long ip, unsigned long direct); 418 void add_ftrace_hash_entry(struct ftrace_hash *hash, struct ftrace_func_entry *entry); 419 struct ftrace_func_entry *ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip); 420 void ftrace_hash_remove(struct ftrace_hash *hash); 421 422 /* The hash used to know what functions callbacks trace */ 423 struct ftrace_ops_hash { 424 struct ftrace_hash __rcu *notrace_hash; 425 struct ftrace_hash __rcu *filter_hash; 426 struct mutex regex_lock; 427 }; 428 429 void ftrace_free_init_mem(void); 430 void ftrace_free_mem(struct module *mod, void *start, void *end); 431 #else 432 static inline void ftrace_free_init_mem(void) 433 { 434 ftrace_boot_snapshot(); 435 } 436 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { } 437 #endif 438 439 /* 440 * Note, ftrace_ops can be referenced outside of RCU protection, unless 441 * the RCU flag is set. If ftrace_ops is allocated and not part of kernel 442 * core data, the unregistering of it will perform a scheduling on all CPUs 443 * to make sure that there are no more users. Depending on the load of the 444 * system that may take a bit of time. 445 * 446 * Any private data added must also take care not to be freed and if private 447 * data is added to a ftrace_ops that is in core code, the user of the 448 * ftrace_ops must perform a schedule_on_each_cpu() before freeing it. 449 */ 450 struct ftrace_ops { 451 ftrace_func_t func; 452 struct ftrace_ops __rcu *next; 453 unsigned long flags; 454 void *private; 455 ftrace_func_t saved_func; 456 #ifdef CONFIG_DYNAMIC_FTRACE 457 struct ftrace_ops_hash local_hash; 458 struct ftrace_ops_hash *func_hash; 459 struct ftrace_ops_hash old_hash; 460 unsigned long trampoline; 461 unsigned long trampoline_size; 462 struct list_head list; 463 struct list_head subop_list; 464 ftrace_ops_func_t ops_func; 465 struct ftrace_ops *managed; 466 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 467 unsigned long direct_call; 468 #endif 469 #endif 470 }; 471 472 extern struct ftrace_ops __rcu *ftrace_ops_list; 473 extern struct ftrace_ops ftrace_list_end; 474 475 /* 476 * Traverse the ftrace_ops_list, invoking all entries. The reason that we 477 * can use rcu_dereference_raw_check() is that elements removed from this list 478 * are simply leaked, so there is no need to interact with a grace-period 479 * mechanism. The rcu_dereference_raw_check() calls are needed to handle 480 * concurrent insertions into the ftrace_ops_list. 481 * 482 * Silly Alpha and silly pointer-speculation compiler optimizations! 483 */ 484 #define do_for_each_ftrace_op(op, list) \ 485 op = rcu_dereference_raw_check(list); \ 486 do 487 488 /* 489 * Optimized for just a single item in the list (as that is the normal case). 490 */ 491 #define while_for_each_ftrace_op(op) \ 492 while (likely(op = rcu_dereference_raw_check((op)->next)) && \ 493 unlikely((op) != &ftrace_list_end)) 494 495 /* 496 * Type of the current tracing. 497 */ 498 enum ftrace_tracing_type_t { 499 FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */ 500 FTRACE_TYPE_RETURN, /* Hook the return of the function */ 501 }; 502 503 /* Current tracing type, default is FTRACE_TYPE_ENTER */ 504 extern enum ftrace_tracing_type_t ftrace_tracing_type; 505 506 /* 507 * The ftrace_ops must be a static and should also 508 * be read_mostly. These functions do modify read_mostly variables 509 * so use them sparely. Never free an ftrace_op or modify the 510 * next pointer after it has been registered. Even after unregistering 511 * it, the next pointer may still be used internally. 512 */ 513 int register_ftrace_function(struct ftrace_ops *ops); 514 int unregister_ftrace_function(struct ftrace_ops *ops); 515 516 extern void ftrace_stub(unsigned long a0, unsigned long a1, 517 struct ftrace_ops *op, struct ftrace_regs *fregs); 518 519 520 int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs); 521 #else /* !CONFIG_FUNCTION_TRACER */ 522 /* 523 * (un)register_ftrace_function must be a macro since the ops parameter 524 * must not be evaluated. 525 */ 526 #define register_ftrace_function(ops) ({ 0; }) 527 #define unregister_ftrace_function(ops) ({ 0; }) 528 static inline void ftrace_kill(void) { } 529 static inline void ftrace_free_init_mem(void) { } 530 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { } 531 static inline int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs) 532 { 533 return -EOPNOTSUPP; 534 } 535 #endif /* CONFIG_FUNCTION_TRACER */ 536 537 struct ftrace_func_entry { 538 struct hlist_node hlist; 539 unsigned long ip; 540 unsigned long direct; /* for direct lookup only */ 541 }; 542 543 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 544 unsigned long ftrace_find_rec_direct(unsigned long ip); 545 int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr); 546 int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr, 547 bool free_filters); 548 int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr); 549 int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr); 550 551 int update_ftrace_direct_add(struct ftrace_ops *ops, struct ftrace_hash *hash); 552 int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace_hash *hash); 553 int update_ftrace_direct_mod(struct ftrace_ops *ops, struct ftrace_hash *hash, bool do_direct_lock); 554 555 void ftrace_stub_direct_tramp(void); 556 557 unsigned long ftrace_hash_count(struct ftrace_hash *hash); 558 559 #else 560 struct ftrace_ops; 561 static inline unsigned long ftrace_find_rec_direct(unsigned long ip) 562 { 563 return 0; 564 } 565 static inline int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr) 566 { 567 return -ENODEV; 568 } 569 static inline int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr, 570 bool free_filters) 571 { 572 return -ENODEV; 573 } 574 static inline int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr) 575 { 576 return -ENODEV; 577 } 578 static inline int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr) 579 { 580 return -ENODEV; 581 } 582 583 static inline int update_ftrace_direct_add(struct ftrace_ops *ops, struct ftrace_hash *hash) 584 { 585 return -ENODEV; 586 } 587 588 static inline int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace_hash *hash) 589 { 590 return -ENODEV; 591 } 592 593 static inline int update_ftrace_direct_mod(struct ftrace_ops *ops, struct ftrace_hash *hash, bool do_direct_lock) 594 { 595 return -ENODEV; 596 } 597 598 static inline unsigned long ftrace_hash_count(struct ftrace_hash *hash) 599 { 600 return 0; 601 } 602 603 /* 604 * This must be implemented by the architecture. 605 * It is the way the ftrace direct_ops helper, when called 606 * via ftrace (because there's other callbacks besides the 607 * direct call), can inform the architecture's trampoline that this 608 * routine has a direct caller, and what the caller is. 609 * 610 * For example, in x86, it returns the direct caller 611 * callback function via the regs->orig_ax parameter. 612 * Then in the ftrace trampoline, if this is set, it makes 613 * the return from the trampoline jump to the direct caller 614 * instead of going back to the function it just traced. 615 */ 616 static inline void arch_ftrace_set_direct_caller(struct ftrace_regs *fregs, 617 unsigned long addr) { } 618 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ 619 620 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_JMP 621 static inline bool ftrace_is_jmp(unsigned long addr) 622 { 623 return addr & 1; 624 } 625 626 static inline unsigned long ftrace_jmp_set(unsigned long addr) 627 { 628 return addr | 1UL; 629 } 630 631 static inline unsigned long ftrace_jmp_get(unsigned long addr) 632 { 633 return addr & ~1UL; 634 } 635 #else 636 static inline bool ftrace_is_jmp(unsigned long addr) 637 { 638 return false; 639 } 640 641 static inline unsigned long ftrace_jmp_set(unsigned long addr) 642 { 643 return addr; 644 } 645 646 static inline unsigned long ftrace_jmp_get(unsigned long addr) 647 { 648 return addr; 649 } 650 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_JMP */ 651 652 #ifdef CONFIG_STACK_TRACER 653 654 int stack_trace_sysctl(const struct ctl_table *table, int write, void *buffer, 655 size_t *lenp, loff_t *ppos); 656 657 /* DO NOT MODIFY THIS VARIABLE DIRECTLY! */ 658 DECLARE_PER_CPU(int, disable_stack_tracer); 659 660 /** 661 * stack_tracer_disable - temporarily disable the stack tracer 662 * 663 * There's a few locations (namely in RCU) where stack tracing 664 * cannot be executed. This function is used to disable stack 665 * tracing during those critical sections. 666 * 667 * This function must be called with preemption or interrupts 668 * disabled and stack_tracer_enable() must be called shortly after 669 * while preemption or interrupts are still disabled. 670 */ 671 static inline void stack_tracer_disable(void) 672 { 673 /* Preemption or interrupts must be disabled */ 674 if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)) 675 WARN_ON_ONCE(!preempt_count() || !irqs_disabled()); 676 this_cpu_inc(disable_stack_tracer); 677 } 678 679 /** 680 * stack_tracer_enable - re-enable the stack tracer 681 * 682 * After stack_tracer_disable() is called, stack_tracer_enable() 683 * must be called shortly afterward. 684 */ 685 static inline void stack_tracer_enable(void) 686 { 687 if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)) 688 WARN_ON_ONCE(!preempt_count() || !irqs_disabled()); 689 this_cpu_dec(disable_stack_tracer); 690 } 691 #else 692 static inline void stack_tracer_disable(void) { } 693 static inline void stack_tracer_enable(void) { } 694 #endif 695 696 enum { 697 FTRACE_UPDATE_CALLS = (1 << 0), 698 FTRACE_DISABLE_CALLS = (1 << 1), 699 FTRACE_UPDATE_TRACE_FUNC = (1 << 2), 700 FTRACE_START_FUNC_RET = (1 << 3), 701 FTRACE_STOP_FUNC_RET = (1 << 4), 702 FTRACE_MAY_SLEEP = (1 << 5), 703 }; 704 705 /* Arches can override ftrace_get_symaddr() to convert fentry_ip to symaddr. */ 706 #ifndef ftrace_get_symaddr 707 /** 708 * ftrace_get_symaddr - return the symbol address from fentry_ip 709 * @fentry_ip: the address of ftrace location 710 * 711 * Get the symbol address from @fentry_ip (fast path). If there is no fast 712 * search path, this returns 0. 713 * User may need to use kallsyms API to find the symbol address. 714 */ 715 #define ftrace_get_symaddr(fentry_ip) (0) 716 #endif 717 718 void ftrace_sync_ipi(void *data); 719 720 #ifdef CONFIG_DYNAMIC_FTRACE 721 722 void ftrace_arch_code_modify_prepare(void); 723 void ftrace_arch_code_modify_post_process(void); 724 725 enum ftrace_bug_type { 726 FTRACE_BUG_UNKNOWN, 727 FTRACE_BUG_INIT, 728 FTRACE_BUG_NOP, 729 FTRACE_BUG_CALL, 730 FTRACE_BUG_UPDATE, 731 }; 732 extern enum ftrace_bug_type ftrace_bug_type; 733 734 /* 735 * Archs can set this to point to a variable that holds the value that was 736 * expected at the call site before calling ftrace_bug(). 737 */ 738 extern const void *ftrace_expected; 739 740 void ftrace_bug(int err, struct dyn_ftrace *rec); 741 742 struct seq_file; 743 744 extern int ftrace_text_reserved(const void *start, const void *end); 745 746 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr); 747 748 bool is_ftrace_trampoline(unsigned long addr); 749 750 /* 751 * The dyn_ftrace record's flags field is split into two parts. 752 * the first part which is '0-FTRACE_REF_MAX' is a counter of 753 * the number of callbacks that have registered the function that 754 * the dyn_ftrace descriptor represents. 755 * 756 * The second part is a mask: 757 * ENABLED - the function is being traced 758 * REGS - the record wants the function to save regs 759 * REGS_EN - the function is set up to save regs. 760 * IPMODIFY - the record allows for the IP address to be changed. 761 * DISABLED - the record is not ready to be touched yet 762 * DIRECT - there is a direct function to call 763 * CALL_OPS - the record can use callsite-specific ops 764 * CALL_OPS_EN - the function is set up to use callsite-specific ops 765 * TOUCHED - A callback was added since boot up 766 * MODIFIED - The function had IPMODIFY or DIRECT attached to it 767 * 768 * When a new ftrace_ops is registered and wants a function to save 769 * pt_regs, the rec->flags REGS is set. When the function has been 770 * set up to save regs, the REG_EN flag is set. Once a function 771 * starts saving regs it will do so until all ftrace_ops are removed 772 * from tracing that function. 773 */ 774 enum { 775 FTRACE_FL_ENABLED = (1UL << 31), 776 FTRACE_FL_REGS = (1UL << 30), 777 FTRACE_FL_REGS_EN = (1UL << 29), 778 FTRACE_FL_TRAMP = (1UL << 28), 779 FTRACE_FL_TRAMP_EN = (1UL << 27), 780 FTRACE_FL_IPMODIFY = (1UL << 26), 781 FTRACE_FL_DISABLED = (1UL << 25), 782 FTRACE_FL_DIRECT = (1UL << 24), 783 FTRACE_FL_DIRECT_EN = (1UL << 23), 784 FTRACE_FL_CALL_OPS = (1UL << 22), 785 FTRACE_FL_CALL_OPS_EN = (1UL << 21), 786 FTRACE_FL_TOUCHED = (1UL << 20), 787 FTRACE_FL_MODIFIED = (1UL << 19), 788 }; 789 790 #define FTRACE_REF_MAX_SHIFT 19 791 #define FTRACE_REF_MAX ((1UL << FTRACE_REF_MAX_SHIFT) - 1) 792 793 #define ftrace_rec_count(rec) ((rec)->flags & FTRACE_REF_MAX) 794 795 struct dyn_ftrace { 796 unsigned long ip; /* address of mcount call-site */ 797 unsigned long flags; 798 struct dyn_arch_ftrace arch; 799 }; 800 801 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip, 802 int remove, int reset); 803 int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips, 804 unsigned int cnt, int remove, int reset); 805 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf, 806 int len, int reset); 807 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf, 808 int len, int reset); 809 void ftrace_set_global_filter(unsigned char *buf, int len, int reset); 810 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset); 811 void ftrace_free_filter(struct ftrace_ops *ops); 812 void ftrace_ops_set_global_filter(struct ftrace_ops *ops); 813 814 /* 815 * The FTRACE_UPDATE_* enum is used to pass information back 816 * from the ftrace_update_record() and ftrace_test_record() 817 * functions. These are called by the code update routines 818 * to find out what is to be done for a given function. 819 * 820 * IGNORE - The function is already what we want it to be 821 * MAKE_CALL - Start tracing the function 822 * MODIFY_CALL - Stop saving regs for the function 823 * MAKE_NOP - Stop tracing the function 824 */ 825 enum { 826 FTRACE_UPDATE_IGNORE, 827 FTRACE_UPDATE_MAKE_CALL, 828 FTRACE_UPDATE_MODIFY_CALL, 829 FTRACE_UPDATE_MAKE_NOP, 830 }; 831 832 enum { 833 FTRACE_ITER_FILTER = (1 << 0), 834 FTRACE_ITER_NOTRACE = (1 << 1), 835 FTRACE_ITER_PRINTALL = (1 << 2), 836 FTRACE_ITER_DO_PROBES = (1 << 3), 837 FTRACE_ITER_PROBE = (1 << 4), 838 FTRACE_ITER_MOD = (1 << 5), 839 FTRACE_ITER_ENABLED = (1 << 6), 840 FTRACE_ITER_TOUCHED = (1 << 7), 841 FTRACE_ITER_ADDRS = (1 << 8), 842 }; 843 844 void arch_ftrace_update_code(int command); 845 void arch_ftrace_update_trampoline(struct ftrace_ops *ops); 846 void *arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec); 847 void arch_ftrace_trampoline_free(struct ftrace_ops *ops); 848 849 struct ftrace_rec_iter; 850 851 struct ftrace_rec_iter *ftrace_rec_iter_start(void); 852 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter); 853 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter); 854 855 #define for_ftrace_rec_iter(iter) \ 856 for (iter = ftrace_rec_iter_start(); \ 857 iter; \ 858 iter = ftrace_rec_iter_next(iter)) 859 860 861 int ftrace_update_record(struct dyn_ftrace *rec, bool enable); 862 int ftrace_test_record(struct dyn_ftrace *rec, bool enable); 863 void ftrace_run_stop_machine(int command); 864 unsigned long ftrace_location(unsigned long ip); 865 unsigned long ftrace_location_range(unsigned long start, unsigned long end); 866 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec); 867 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec); 868 869 extern ftrace_func_t ftrace_trace_function; 870 struct trace_array; 871 872 int ftrace_regex_open(struct trace_array *tr, struct ftrace_ops *ops, int flag, 873 struct inode *inode, struct file *file); 874 ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf, 875 size_t cnt, loff_t *ppos); 876 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf, 877 size_t cnt, loff_t *ppos); 878 int ftrace_regex_release(struct inode *inode, struct file *file); 879 880 void __init 881 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable); 882 883 /* defined in arch */ 884 extern int ftrace_dyn_arch_init(void); 885 extern void ftrace_replace_code(int enable); 886 extern int ftrace_update_ftrace_func(ftrace_func_t func); 887 extern void ftrace_caller(void); 888 extern void ftrace_regs_caller(void); 889 extern void ftrace_call(void); 890 extern void ftrace_regs_call(void); 891 extern void mcount_call(void); 892 893 void ftrace_modify_all_code(int command); 894 895 #ifndef FTRACE_ADDR 896 #define FTRACE_ADDR ((unsigned long)ftrace_caller) 897 #endif 898 899 #ifndef FTRACE_GRAPH_ADDR 900 #define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller) 901 #endif 902 903 #ifndef FTRACE_REGS_ADDR 904 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS 905 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller) 906 #else 907 # define FTRACE_REGS_ADDR FTRACE_ADDR 908 #endif 909 #endif 910 911 /* 912 * If an arch would like functions that are only traced 913 * by the function graph tracer to jump directly to its own 914 * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR 915 * to be that address to jump to. 916 */ 917 #ifndef FTRACE_GRAPH_TRAMP_ADDR 918 #define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0) 919 #endif 920 921 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 922 extern void ftrace_graph_caller(void); 923 extern int ftrace_enable_ftrace_graph_caller(void); 924 extern int ftrace_disable_ftrace_graph_caller(void); 925 #else 926 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; } 927 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; } 928 #endif 929 930 /** 931 * ftrace_make_nop - convert code into nop 932 * @mod: module structure if called by module load initialization 933 * @rec: the call site record (e.g. mcount/fentry) 934 * @addr: the address that the call site should be calling 935 * 936 * This is a very sensitive operation and great care needs 937 * to be taken by the arch. The operation should carefully 938 * read the location, check to see if what is read is indeed 939 * what we expect it to be, and then on success of the compare, 940 * it should write to the location. 941 * 942 * The code segment at @rec->ip should be a caller to @addr 943 * 944 * Return must be: 945 * 0 on success 946 * -EFAULT on error reading the location 947 * -EINVAL on a failed compare of the contents 948 * -EPERM on error writing to the location 949 * Any other value will be considered a failure. 950 */ 951 extern int ftrace_make_nop(struct module *mod, 952 struct dyn_ftrace *rec, unsigned long addr); 953 954 /** 955 * ftrace_need_init_nop - return whether nop call sites should be initialized 956 * 957 * Normally the compiler's -mnop-mcount generates suitable nops, so we don't 958 * need to call ftrace_init_nop() if the code is built with that flag. 959 * Architectures where this is not always the case may define their own 960 * condition. 961 * 962 * Return must be: 963 * 0 if ftrace_init_nop() should be called 964 * Nonzero if ftrace_init_nop() should not be called 965 */ 966 967 #ifndef ftrace_need_init_nop 968 #define ftrace_need_init_nop() (!__is_defined(CC_USING_NOP_MCOUNT)) 969 #endif 970 971 /** 972 * ftrace_init_nop - initialize a nop call site 973 * @mod: module structure if called by module load initialization 974 * @rec: the call site record (e.g. mcount/fentry) 975 * 976 * This is a very sensitive operation and great care needs 977 * to be taken by the arch. The operation should carefully 978 * read the location, check to see if what is read is indeed 979 * what we expect it to be, and then on success of the compare, 980 * it should write to the location. 981 * 982 * The code segment at @rec->ip should contain the contents created by 983 * the compiler 984 * 985 * Return must be: 986 * 0 on success 987 * -EFAULT on error reading the location 988 * -EINVAL on a failed compare of the contents 989 * -EPERM on error writing to the location 990 * Any other value will be considered a failure. 991 */ 992 #ifndef ftrace_init_nop 993 static inline int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) 994 { 995 return ftrace_make_nop(mod, rec, MCOUNT_ADDR); 996 } 997 #endif 998 999 /** 1000 * ftrace_make_call - convert a nop call site into a call to addr 1001 * @rec: the call site record (e.g. mcount/fentry) 1002 * @addr: the address that the call site should call 1003 * 1004 * This is a very sensitive operation and great care needs 1005 * to be taken by the arch. The operation should carefully 1006 * read the location, check to see if what is read is indeed 1007 * what we expect it to be, and then on success of the compare, 1008 * it should write to the location. 1009 * 1010 * The code segment at @rec->ip should be a nop 1011 * 1012 * Return must be: 1013 * 0 on success 1014 * -EFAULT on error reading the location 1015 * -EINVAL on a failed compare of the contents 1016 * -EPERM on error writing to the location 1017 * Any other value will be considered a failure. 1018 */ 1019 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr); 1020 1021 #if defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS) || \ 1022 defined(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS) || \ 1023 defined(CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS) 1024 /** 1025 * ftrace_modify_call - convert from one addr to another (no nop) 1026 * @rec: the call site record (e.g. mcount/fentry) 1027 * @old_addr: the address expected to be currently called to 1028 * @addr: the address to change to 1029 * 1030 * This is a very sensitive operation and great care needs 1031 * to be taken by the arch. The operation should carefully 1032 * read the location, check to see if what is read is indeed 1033 * what we expect it to be, and then on success of the compare, 1034 * it should write to the location. 1035 * 1036 * When using call ops, this is called when the associated ops change, even 1037 * when (addr == old_addr). 1038 * 1039 * The code segment at @rec->ip should be a caller to @old_addr 1040 * 1041 * Return must be: 1042 * 0 on success 1043 * -EFAULT on error reading the location 1044 * -EINVAL on a failed compare of the contents 1045 * -EPERM on error writing to the location 1046 * Any other value will be considered a failure. 1047 */ 1048 extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, 1049 unsigned long addr); 1050 #else 1051 /* Should never be called */ 1052 static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, 1053 unsigned long addr) 1054 { 1055 return -EINVAL; 1056 } 1057 #endif 1058 1059 extern int skip_trace(unsigned long ip); 1060 extern void ftrace_module_init(struct module *mod); 1061 extern void ftrace_module_enable(struct module *mod); 1062 extern void ftrace_release_mod(struct module *mod); 1063 #else /* CONFIG_DYNAMIC_FTRACE */ 1064 static inline int skip_trace(unsigned long ip) { return 0; } 1065 static inline void ftrace_module_init(struct module *mod) { } 1066 static inline void ftrace_module_enable(struct module *mod) { } 1067 static inline void ftrace_release_mod(struct module *mod) { } 1068 static inline int ftrace_text_reserved(const void *start, const void *end) 1069 { 1070 return 0; 1071 } 1072 static inline unsigned long ftrace_location(unsigned long ip) 1073 { 1074 return 0; 1075 } 1076 1077 /* 1078 * Again users of functions that have ftrace_ops may not 1079 * have them defined when ftrace is not enabled, but these 1080 * functions may still be called. Use a macro instead of inline. 1081 */ 1082 #define ftrace_regex_open(tr, ops, flag, inode, file) ({ -ENODEV; }) 1083 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0) 1084 #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; }) 1085 #define ftrace_set_filter_ips(ops, ips, cnt, remove, reset) ({ -ENODEV; }) 1086 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; }) 1087 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; }) 1088 #define ftrace_free_filter(ops) do { } while (0) 1089 #define ftrace_ops_set_global_filter(ops) do { } while (0) 1090 1091 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf, 1092 size_t cnt, loff_t *ppos) { return -ENODEV; } 1093 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf, 1094 size_t cnt, loff_t *ppos) { return -ENODEV; } 1095 static inline int 1096 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; } 1097 1098 static inline bool is_ftrace_trampoline(unsigned long addr) 1099 { 1100 return false; 1101 } 1102 #endif /* CONFIG_DYNAMIC_FTRACE */ 1103 1104 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 1105 #ifndef ftrace_graph_func 1106 # define ftrace_graph_func ftrace_stub 1107 # define FTRACE_OPS_GRAPH_STUB FTRACE_OPS_FL_STUB 1108 /* 1109 * The function graph is called every time the function tracer is called. 1110 * It must always test the ops hash and cannot just directly call 1111 * the handler. 1112 */ 1113 # define FGRAPH_NO_DIRECT 1 1114 #else 1115 # define FTRACE_OPS_GRAPH_STUB 0 1116 # define FGRAPH_NO_DIRECT 0 1117 #endif 1118 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 1119 1120 /* totally disable ftrace - can not re-enable after this */ 1121 void ftrace_kill(void); 1122 1123 static inline void tracer_disable(void) 1124 { 1125 #ifdef CONFIG_FUNCTION_TRACER 1126 ftrace_enabled = 0; 1127 #endif 1128 } 1129 1130 /* 1131 * Ftrace disable/restore without lock. Some synchronization mechanism 1132 * must be used to prevent ftrace_enabled to be changed between 1133 * disable/restore. 1134 */ 1135 static inline int __ftrace_enabled_save(void) 1136 { 1137 #ifdef CONFIG_FUNCTION_TRACER 1138 int saved_ftrace_enabled = ftrace_enabled; 1139 ftrace_enabled = 0; 1140 return saved_ftrace_enabled; 1141 #else 1142 return 0; 1143 #endif 1144 } 1145 1146 static inline void __ftrace_enabled_restore(int enabled) 1147 { 1148 #ifdef CONFIG_FUNCTION_TRACER 1149 ftrace_enabled = enabled; 1150 #endif 1151 } 1152 1153 /* All archs should have this, but we define it for consistency */ 1154 #ifndef ftrace_return_address0 1155 # define ftrace_return_address0 __builtin_return_address(0) 1156 #endif 1157 1158 /* Archs may use other ways for ADDR1 and beyond */ 1159 #ifndef ftrace_return_address 1160 # ifdef CONFIG_FRAME_POINTER 1161 # define ftrace_return_address(n) __builtin_return_address(n) 1162 # else 1163 # define ftrace_return_address(n) 0UL 1164 # endif 1165 #endif 1166 1167 #define CALLER_ADDR0 ((unsigned long)ftrace_return_address0) 1168 #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1)) 1169 #define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2)) 1170 #define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3)) 1171 #define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4)) 1172 #define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5)) 1173 #define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6)) 1174 1175 static __always_inline unsigned long get_lock_parent_ip(void) 1176 { 1177 unsigned long addr = CALLER_ADDR0; 1178 1179 if (!in_lock_functions(addr)) 1180 return addr; 1181 addr = CALLER_ADDR1; 1182 if (!in_lock_functions(addr)) 1183 return addr; 1184 return CALLER_ADDR2; 1185 } 1186 1187 #ifdef CONFIG_TRACE_PREEMPT_TOGGLE 1188 extern void trace_preempt_on(unsigned long a0, unsigned long a1); 1189 extern void trace_preempt_off(unsigned long a0, unsigned long a1); 1190 #else 1191 /* 1192 * Use defines instead of static inlines because some arches will make code out 1193 * of the CALLER_ADDR, when we really want these to be a real nop. 1194 */ 1195 # define trace_preempt_on(a0, a1) do { } while (0) 1196 # define trace_preempt_off(a0, a1) do { } while (0) 1197 #endif 1198 1199 #ifdef CONFIG_DYNAMIC_FTRACE 1200 extern void ftrace_init(void); 1201 #ifdef CC_USING_PATCHABLE_FUNCTION_ENTRY 1202 #define FTRACE_CALLSITE_SECTION "__patchable_function_entries" 1203 #else 1204 #define FTRACE_CALLSITE_SECTION "__mcount_loc" 1205 #endif 1206 #else 1207 static inline void ftrace_init(void) { } 1208 #endif 1209 1210 /* 1211 * Structure that defines an entry function trace. 1212 * It's already packed but the attribute "packed" is needed 1213 * to remove extra padding at the end. 1214 */ 1215 struct ftrace_graph_ent { 1216 unsigned long func; /* Current function */ 1217 long depth; /* signed to check for less than zero */ 1218 } __packed; 1219 1220 /* 1221 * Structure that defines an entry function trace with retaddr. 1222 */ 1223 struct fgraph_retaddr_ent { 1224 struct ftrace_graph_ent ent; 1225 unsigned long retaddr; /* Return address */ 1226 } __packed; 1227 1228 /* 1229 * Structure that defines a return function trace. 1230 * It's already packed but the attribute "packed" is needed 1231 * to remove extra padding at the end. 1232 */ 1233 struct ftrace_graph_ret { 1234 unsigned long func; /* Current function */ 1235 #ifdef CONFIG_FUNCTION_GRAPH_RETVAL 1236 unsigned long retval; 1237 #endif 1238 int depth; 1239 /* Number of functions that overran the depth limit for current task */ 1240 unsigned int overrun; 1241 } __packed; 1242 1243 struct fgraph_ops; 1244 1245 /* Type of the callback handlers for tracing function graph*/ 1246 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *, 1247 struct fgraph_ops *, 1248 struct ftrace_regs *); /* return */ 1249 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *, 1250 struct fgraph_ops *, 1251 struct ftrace_regs *); /* entry */ 1252 1253 extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace, 1254 struct fgraph_ops *gops, 1255 struct ftrace_regs *fregs); 1256 bool ftrace_pids_enabled(struct ftrace_ops *ops); 1257 1258 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 1259 1260 struct fgraph_ops { 1261 trace_func_graph_ent_t entryfunc; 1262 trace_func_graph_ret_t retfunc; 1263 struct ftrace_ops ops; /* for the hash lists */ 1264 void *private; 1265 trace_func_graph_ent_t saved_func; 1266 int idx; 1267 }; 1268 1269 void *fgraph_reserve_data(int idx, int size_bytes); 1270 void *fgraph_retrieve_data(int idx, int *size_bytes); 1271 void *fgraph_retrieve_parent_data(int idx, int *size_bytes, int depth); 1272 1273 /* 1274 * Stack of return addresses for functions 1275 * of a thread. 1276 * Used in struct thread_info 1277 */ 1278 struct ftrace_ret_stack { 1279 unsigned long ret; 1280 unsigned long func; 1281 #ifdef HAVE_FUNCTION_GRAPH_FP_TEST 1282 unsigned long fp; 1283 #endif 1284 unsigned long *retp; 1285 }; 1286 1287 /* 1288 * Primary handler of a function return. 1289 * It relays on ftrace_return_to_handler. 1290 * Defined in entry_32/64.S 1291 */ 1292 extern void return_to_handler(void); 1293 1294 extern int 1295 function_graph_enter_regs(unsigned long ret, unsigned long func, 1296 unsigned long frame_pointer, unsigned long *retp, 1297 struct ftrace_regs *fregs); 1298 1299 static inline int function_graph_enter(unsigned long ret, unsigned long func, 1300 unsigned long fp, unsigned long *retp) 1301 { 1302 return function_graph_enter_regs(ret, func, fp, retp, NULL); 1303 } 1304 1305 struct ftrace_ret_stack * 1306 ftrace_graph_get_ret_stack(struct task_struct *task, int skip); 1307 unsigned long ftrace_graph_top_ret_addr(struct task_struct *task); 1308 1309 unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx, 1310 unsigned long ret, unsigned long *retp); 1311 unsigned long *fgraph_get_task_var(struct fgraph_ops *gops); 1312 1313 /* 1314 * Sometimes we don't want to trace a function with the function 1315 * graph tracer but we want them to keep traced by the usual function 1316 * tracer if the function graph tracer is not configured. 1317 */ 1318 #define __notrace_funcgraph notrace 1319 1320 #define FTRACE_RETFUNC_DEPTH 50 1321 #define FTRACE_RETSTACK_ALLOC_SIZE 32 1322 1323 extern int register_ftrace_graph(struct fgraph_ops *ops); 1324 extern void unregister_ftrace_graph(struct fgraph_ops *ops); 1325 1326 /** 1327 * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called 1328 * 1329 * ftrace_graph_stop() is called when a severe error is detected in 1330 * the function graph tracing. This function is called by the critical 1331 * paths of function graph to keep those paths from doing any more harm. 1332 */ 1333 DECLARE_STATIC_KEY_FALSE(kill_ftrace_graph); 1334 1335 static inline bool ftrace_graph_is_dead(void) 1336 { 1337 return static_branch_unlikely(&kill_ftrace_graph); 1338 } 1339 1340 extern void ftrace_graph_stop(void); 1341 1342 /* The current handlers in use */ 1343 extern trace_func_graph_ret_t ftrace_graph_return; 1344 extern trace_func_graph_ent_t ftrace_graph_entry; 1345 1346 extern void ftrace_graph_init_task(struct task_struct *t); 1347 extern void ftrace_graph_exit_task(struct task_struct *t); 1348 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu); 1349 1350 /* Used by assembly, but to quiet sparse warnings */ 1351 extern struct ftrace_ops *function_trace_op; 1352 1353 static inline void pause_graph_tracing(void) 1354 { 1355 atomic_inc(¤t->tracing_graph_pause); 1356 } 1357 1358 static inline void unpause_graph_tracing(void) 1359 { 1360 atomic_dec(¤t->tracing_graph_pause); 1361 } 1362 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */ 1363 1364 #define __notrace_funcgraph 1365 1366 static inline void ftrace_graph_init_task(struct task_struct *t) { } 1367 static inline void ftrace_graph_exit_task(struct task_struct *t) { } 1368 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { } 1369 1370 /* Define as macros as fgraph_ops may not be defined */ 1371 #define register_ftrace_graph(ops) ({ -1; }) 1372 #define unregister_ftrace_graph(ops) do { } while (0) 1373 1374 static inline unsigned long 1375 ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret, 1376 unsigned long *retp) 1377 { 1378 return ret; 1379 } 1380 1381 static inline void pause_graph_tracing(void) { } 1382 static inline void unpause_graph_tracing(void) { } 1383 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 1384 1385 #ifdef CONFIG_TRACING 1386 enum ftrace_dump_mode; 1387 1388 extern int ftrace_dump_on_oops_enabled(void); 1389 1390 extern void disable_trace_on_warning(void); 1391 1392 #else /* CONFIG_TRACING */ 1393 static inline void disable_trace_on_warning(void) { } 1394 #endif /* CONFIG_TRACING */ 1395 1396 #ifdef CONFIG_FTRACE_SYSCALLS 1397 1398 unsigned long arch_syscall_addr(int nr); 1399 1400 #endif /* CONFIG_FTRACE_SYSCALLS */ 1401 1402 #endif /* _LINUX_FTRACE_H */ 1403