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_TRACING 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); 418 419 /* The hash used to know what functions callbacks trace */ 420 struct ftrace_ops_hash { 421 struct ftrace_hash __rcu *notrace_hash; 422 struct ftrace_hash __rcu *filter_hash; 423 struct mutex regex_lock; 424 }; 425 426 void ftrace_free_init_mem(void); 427 void ftrace_free_mem(struct module *mod, void *start, void *end); 428 #else 429 static inline void ftrace_free_init_mem(void) 430 { 431 ftrace_boot_snapshot(); 432 } 433 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { } 434 #endif 435 436 /* 437 * Note, ftrace_ops can be referenced outside of RCU protection, unless 438 * the RCU flag is set. If ftrace_ops is allocated and not part of kernel 439 * core data, the unregistering of it will perform a scheduling on all CPUs 440 * to make sure that there are no more users. Depending on the load of the 441 * system that may take a bit of time. 442 * 443 * Any private data added must also take care not to be freed and if private 444 * data is added to a ftrace_ops that is in core code, the user of the 445 * ftrace_ops must perform a schedule_on_each_cpu() before freeing it. 446 */ 447 struct ftrace_ops { 448 ftrace_func_t func; 449 struct ftrace_ops __rcu *next; 450 unsigned long flags; 451 void *private; 452 ftrace_func_t saved_func; 453 #ifdef CONFIG_DYNAMIC_FTRACE 454 struct ftrace_ops_hash local_hash; 455 struct ftrace_ops_hash *func_hash; 456 struct ftrace_ops_hash old_hash; 457 unsigned long trampoline; 458 unsigned long trampoline_size; 459 struct list_head list; 460 struct list_head subop_list; 461 ftrace_ops_func_t ops_func; 462 struct ftrace_ops *managed; 463 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 464 unsigned long direct_call; 465 #endif 466 #endif 467 }; 468 469 extern struct ftrace_ops __rcu *ftrace_ops_list; 470 extern struct ftrace_ops ftrace_list_end; 471 472 /* 473 * Traverse the ftrace_ops_list, invoking all entries. The reason that we 474 * can use rcu_dereference_raw_check() is that elements removed from this list 475 * are simply leaked, so there is no need to interact with a grace-period 476 * mechanism. The rcu_dereference_raw_check() calls are needed to handle 477 * concurrent insertions into the ftrace_ops_list. 478 * 479 * Silly Alpha and silly pointer-speculation compiler optimizations! 480 */ 481 #define do_for_each_ftrace_op(op, list) \ 482 op = rcu_dereference_raw_check(list); \ 483 do 484 485 /* 486 * Optimized for just a single item in the list (as that is the normal case). 487 */ 488 #define while_for_each_ftrace_op(op) \ 489 while (likely(op = rcu_dereference_raw_check((op)->next)) && \ 490 unlikely((op) != &ftrace_list_end)) 491 492 /* 493 * Type of the current tracing. 494 */ 495 enum ftrace_tracing_type_t { 496 FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */ 497 FTRACE_TYPE_RETURN, /* Hook the return of the function */ 498 }; 499 500 /* Current tracing type, default is FTRACE_TYPE_ENTER */ 501 extern enum ftrace_tracing_type_t ftrace_tracing_type; 502 503 /* 504 * The ftrace_ops must be a static and should also 505 * be read_mostly. These functions do modify read_mostly variables 506 * so use them sparely. Never free an ftrace_op or modify the 507 * next pointer after it has been registered. Even after unregistering 508 * it, the next pointer may still be used internally. 509 */ 510 int register_ftrace_function(struct ftrace_ops *ops); 511 int unregister_ftrace_function(struct ftrace_ops *ops); 512 513 extern void ftrace_stub(unsigned long a0, unsigned long a1, 514 struct ftrace_ops *op, struct ftrace_regs *fregs); 515 516 517 int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs); 518 #else /* !CONFIG_FUNCTION_TRACER */ 519 /* 520 * (un)register_ftrace_function must be a macro since the ops parameter 521 * must not be evaluated. 522 */ 523 #define register_ftrace_function(ops) ({ 0; }) 524 #define unregister_ftrace_function(ops) ({ 0; }) 525 static inline void ftrace_kill(void) { } 526 static inline void ftrace_free_init_mem(void) { } 527 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { } 528 static inline int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs) 529 { 530 return -EOPNOTSUPP; 531 } 532 #endif /* CONFIG_FUNCTION_TRACER */ 533 534 struct ftrace_func_entry { 535 struct hlist_node hlist; 536 unsigned long ip; 537 unsigned long direct; /* for direct lookup only */ 538 }; 539 540 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 541 unsigned long ftrace_find_rec_direct(unsigned long ip); 542 int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr); 543 int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr, 544 bool free_filters); 545 int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr); 546 int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr); 547 548 int update_ftrace_direct_add(struct ftrace_ops *ops, struct ftrace_hash *hash); 549 int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace_hash *hash); 550 int update_ftrace_direct_mod(struct ftrace_ops *ops, struct ftrace_hash *hash, bool do_direct_lock); 551 552 void ftrace_stub_direct_tramp(void); 553 554 #else 555 struct ftrace_ops; 556 static inline unsigned long ftrace_find_rec_direct(unsigned long ip) 557 { 558 return 0; 559 } 560 static inline int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr) 561 { 562 return -ENODEV; 563 } 564 static inline int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr, 565 bool free_filters) 566 { 567 return -ENODEV; 568 } 569 static inline int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr) 570 { 571 return -ENODEV; 572 } 573 static inline int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr) 574 { 575 return -ENODEV; 576 } 577 578 static inline int update_ftrace_direct_add(struct ftrace_ops *ops, struct ftrace_hash *hash) 579 { 580 return -ENODEV; 581 } 582 583 static inline int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace_hash *hash) 584 { 585 return -ENODEV; 586 } 587 588 static inline int update_ftrace_direct_mod(struct ftrace_ops *ops, struct ftrace_hash *hash, bool do_direct_lock) 589 { 590 return -ENODEV; 591 } 592 593 /* 594 * This must be implemented by the architecture. 595 * It is the way the ftrace direct_ops helper, when called 596 * via ftrace (because there's other callbacks besides the 597 * direct call), can inform the architecture's trampoline that this 598 * routine has a direct caller, and what the caller is. 599 * 600 * For example, in x86, it returns the direct caller 601 * callback function via the regs->orig_ax parameter. 602 * Then in the ftrace trampoline, if this is set, it makes 603 * the return from the trampoline jump to the direct caller 604 * instead of going back to the function it just traced. 605 */ 606 static inline void arch_ftrace_set_direct_caller(struct ftrace_regs *fregs, 607 unsigned long addr) { } 608 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ 609 610 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_JMP 611 static inline bool ftrace_is_jmp(unsigned long addr) 612 { 613 return addr & 1; 614 } 615 616 static inline unsigned long ftrace_jmp_set(unsigned long addr) 617 { 618 return addr | 1UL; 619 } 620 621 static inline unsigned long ftrace_jmp_get(unsigned long addr) 622 { 623 return addr & ~1UL; 624 } 625 #else 626 static inline bool ftrace_is_jmp(unsigned long addr) 627 { 628 return false; 629 } 630 631 static inline unsigned long ftrace_jmp_set(unsigned long addr) 632 { 633 return addr; 634 } 635 636 static inline unsigned long ftrace_jmp_get(unsigned long addr) 637 { 638 return addr; 639 } 640 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_JMP */ 641 642 #ifdef CONFIG_STACK_TRACER 643 644 int stack_trace_sysctl(const struct ctl_table *table, int write, void *buffer, 645 size_t *lenp, loff_t *ppos); 646 647 /* DO NOT MODIFY THIS VARIABLE DIRECTLY! */ 648 DECLARE_PER_CPU(int, disable_stack_tracer); 649 650 /** 651 * stack_tracer_disable - temporarily disable the stack tracer 652 * 653 * There's a few locations (namely in RCU) where stack tracing 654 * cannot be executed. This function is used to disable stack 655 * tracing during those critical sections. 656 * 657 * This function must be called with preemption or interrupts 658 * disabled and stack_tracer_enable() must be called shortly after 659 * while preemption or interrupts are still disabled. 660 */ 661 static inline void stack_tracer_disable(void) 662 { 663 /* Preemption or interrupts must be disabled */ 664 if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)) 665 WARN_ON_ONCE(!preempt_count() || !irqs_disabled()); 666 this_cpu_inc(disable_stack_tracer); 667 } 668 669 /** 670 * stack_tracer_enable - re-enable the stack tracer 671 * 672 * After stack_tracer_disable() is called, stack_tracer_enable() 673 * must be called shortly afterward. 674 */ 675 static inline void stack_tracer_enable(void) 676 { 677 if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)) 678 WARN_ON_ONCE(!preempt_count() || !irqs_disabled()); 679 this_cpu_dec(disable_stack_tracer); 680 } 681 #else 682 static inline void stack_tracer_disable(void) { } 683 static inline void stack_tracer_enable(void) { } 684 #endif 685 686 enum { 687 FTRACE_UPDATE_CALLS = (1 << 0), 688 FTRACE_DISABLE_CALLS = (1 << 1), 689 FTRACE_UPDATE_TRACE_FUNC = (1 << 2), 690 FTRACE_START_FUNC_RET = (1 << 3), 691 FTRACE_STOP_FUNC_RET = (1 << 4), 692 FTRACE_MAY_SLEEP = (1 << 5), 693 }; 694 695 /* Arches can override ftrace_get_symaddr() to convert fentry_ip to symaddr. */ 696 #ifndef ftrace_get_symaddr 697 /** 698 * ftrace_get_symaddr - return the symbol address from fentry_ip 699 * @fentry_ip: the address of ftrace location 700 * 701 * Get the symbol address from @fentry_ip (fast path). If there is no fast 702 * search path, this returns 0. 703 * User may need to use kallsyms API to find the symbol address. 704 */ 705 #define ftrace_get_symaddr(fentry_ip) (0) 706 #endif 707 708 void ftrace_sync_ipi(void *data); 709 710 #ifdef CONFIG_DYNAMIC_FTRACE 711 712 void ftrace_arch_code_modify_prepare(void); 713 void ftrace_arch_code_modify_post_process(void); 714 715 enum ftrace_bug_type { 716 FTRACE_BUG_UNKNOWN, 717 FTRACE_BUG_INIT, 718 FTRACE_BUG_NOP, 719 FTRACE_BUG_CALL, 720 FTRACE_BUG_UPDATE, 721 }; 722 extern enum ftrace_bug_type ftrace_bug_type; 723 724 /* 725 * Archs can set this to point to a variable that holds the value that was 726 * expected at the call site before calling ftrace_bug(). 727 */ 728 extern const void *ftrace_expected; 729 730 void ftrace_bug(int err, struct dyn_ftrace *rec); 731 732 struct seq_file; 733 734 extern int ftrace_text_reserved(const void *start, const void *end); 735 736 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr); 737 738 bool is_ftrace_trampoline(unsigned long addr); 739 740 /* 741 * The dyn_ftrace record's flags field is split into two parts. 742 * the first part which is '0-FTRACE_REF_MAX' is a counter of 743 * the number of callbacks that have registered the function that 744 * the dyn_ftrace descriptor represents. 745 * 746 * The second part is a mask: 747 * ENABLED - the function is being traced 748 * REGS - the record wants the function to save regs 749 * REGS_EN - the function is set up to save regs. 750 * IPMODIFY - the record allows for the IP address to be changed. 751 * DISABLED - the record is not ready to be touched yet 752 * DIRECT - there is a direct function to call 753 * CALL_OPS - the record can use callsite-specific ops 754 * CALL_OPS_EN - the function is set up to use callsite-specific ops 755 * TOUCHED - A callback was added since boot up 756 * MODIFIED - The function had IPMODIFY or DIRECT attached to it 757 * 758 * When a new ftrace_ops is registered and wants a function to save 759 * pt_regs, the rec->flags REGS is set. When the function has been 760 * set up to save regs, the REG_EN flag is set. Once a function 761 * starts saving regs it will do so until all ftrace_ops are removed 762 * from tracing that function. 763 */ 764 enum { 765 FTRACE_FL_ENABLED = (1UL << 31), 766 FTRACE_FL_REGS = (1UL << 30), 767 FTRACE_FL_REGS_EN = (1UL << 29), 768 FTRACE_FL_TRAMP = (1UL << 28), 769 FTRACE_FL_TRAMP_EN = (1UL << 27), 770 FTRACE_FL_IPMODIFY = (1UL << 26), 771 FTRACE_FL_DISABLED = (1UL << 25), 772 FTRACE_FL_DIRECT = (1UL << 24), 773 FTRACE_FL_DIRECT_EN = (1UL << 23), 774 FTRACE_FL_CALL_OPS = (1UL << 22), 775 FTRACE_FL_CALL_OPS_EN = (1UL << 21), 776 FTRACE_FL_TOUCHED = (1UL << 20), 777 FTRACE_FL_MODIFIED = (1UL << 19), 778 }; 779 780 #define FTRACE_REF_MAX_SHIFT 19 781 #define FTRACE_REF_MAX ((1UL << FTRACE_REF_MAX_SHIFT) - 1) 782 783 #define ftrace_rec_count(rec) ((rec)->flags & FTRACE_REF_MAX) 784 785 struct dyn_ftrace { 786 unsigned long ip; /* address of mcount call-site */ 787 unsigned long flags; 788 struct dyn_arch_ftrace arch; 789 }; 790 791 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip, 792 int remove, int reset); 793 int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips, 794 unsigned int cnt, int remove, int reset); 795 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf, 796 int len, int reset); 797 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf, 798 int len, int reset); 799 void ftrace_set_global_filter(unsigned char *buf, int len, int reset); 800 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset); 801 void ftrace_free_filter(struct ftrace_ops *ops); 802 void ftrace_ops_set_global_filter(struct ftrace_ops *ops); 803 804 /* 805 * The FTRACE_UPDATE_* enum is used to pass information back 806 * from the ftrace_update_record() and ftrace_test_record() 807 * functions. These are called by the code update routines 808 * to find out what is to be done for a given function. 809 * 810 * IGNORE - The function is already what we want it to be 811 * MAKE_CALL - Start tracing the function 812 * MODIFY_CALL - Stop saving regs for the function 813 * MAKE_NOP - Stop tracing the function 814 */ 815 enum { 816 FTRACE_UPDATE_IGNORE, 817 FTRACE_UPDATE_MAKE_CALL, 818 FTRACE_UPDATE_MODIFY_CALL, 819 FTRACE_UPDATE_MAKE_NOP, 820 }; 821 822 enum { 823 FTRACE_ITER_FILTER = (1 << 0), 824 FTRACE_ITER_NOTRACE = (1 << 1), 825 FTRACE_ITER_PRINTALL = (1 << 2), 826 FTRACE_ITER_DO_PROBES = (1 << 3), 827 FTRACE_ITER_PROBE = (1 << 4), 828 FTRACE_ITER_MOD = (1 << 5), 829 FTRACE_ITER_ENABLED = (1 << 6), 830 FTRACE_ITER_TOUCHED = (1 << 7), 831 FTRACE_ITER_ADDRS = (1 << 8), 832 }; 833 834 void arch_ftrace_update_code(int command); 835 void arch_ftrace_update_trampoline(struct ftrace_ops *ops); 836 void *arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec); 837 void arch_ftrace_trampoline_free(struct ftrace_ops *ops); 838 839 struct ftrace_rec_iter; 840 841 struct ftrace_rec_iter *ftrace_rec_iter_start(void); 842 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter); 843 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter); 844 845 #define for_ftrace_rec_iter(iter) \ 846 for (iter = ftrace_rec_iter_start(); \ 847 iter; \ 848 iter = ftrace_rec_iter_next(iter)) 849 850 851 int ftrace_update_record(struct dyn_ftrace *rec, bool enable); 852 int ftrace_test_record(struct dyn_ftrace *rec, bool enable); 853 void ftrace_run_stop_machine(int command); 854 unsigned long ftrace_location(unsigned long ip); 855 unsigned long ftrace_location_range(unsigned long start, unsigned long end); 856 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec); 857 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec); 858 859 extern ftrace_func_t ftrace_trace_function; 860 861 int ftrace_regex_open(struct ftrace_ops *ops, int flag, 862 struct inode *inode, struct file *file); 863 ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf, 864 size_t cnt, loff_t *ppos); 865 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf, 866 size_t cnt, loff_t *ppos); 867 int ftrace_regex_release(struct inode *inode, struct file *file); 868 869 void __init 870 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable); 871 872 /* defined in arch */ 873 extern int ftrace_dyn_arch_init(void); 874 extern void ftrace_replace_code(int enable); 875 extern int ftrace_update_ftrace_func(ftrace_func_t func); 876 extern void ftrace_caller(void); 877 extern void ftrace_regs_caller(void); 878 extern void ftrace_call(void); 879 extern void ftrace_regs_call(void); 880 extern void mcount_call(void); 881 882 void ftrace_modify_all_code(int command); 883 884 #ifndef FTRACE_ADDR 885 #define FTRACE_ADDR ((unsigned long)ftrace_caller) 886 #endif 887 888 #ifndef FTRACE_GRAPH_ADDR 889 #define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller) 890 #endif 891 892 #ifndef FTRACE_REGS_ADDR 893 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS 894 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller) 895 #else 896 # define FTRACE_REGS_ADDR FTRACE_ADDR 897 #endif 898 #endif 899 900 /* 901 * If an arch would like functions that are only traced 902 * by the function graph tracer to jump directly to its own 903 * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR 904 * to be that address to jump to. 905 */ 906 #ifndef FTRACE_GRAPH_TRAMP_ADDR 907 #define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0) 908 #endif 909 910 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 911 extern void ftrace_graph_caller(void); 912 extern int ftrace_enable_ftrace_graph_caller(void); 913 extern int ftrace_disable_ftrace_graph_caller(void); 914 #else 915 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; } 916 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; } 917 #endif 918 919 /** 920 * ftrace_make_nop - convert code into nop 921 * @mod: module structure if called by module load initialization 922 * @rec: the call site record (e.g. mcount/fentry) 923 * @addr: the address that the call site should be calling 924 * 925 * This is a very sensitive operation and great care needs 926 * to be taken by the arch. The operation should carefully 927 * read the location, check to see if what is read is indeed 928 * what we expect it to be, and then on success of the compare, 929 * it should write to the location. 930 * 931 * The code segment at @rec->ip should be a caller to @addr 932 * 933 * Return must be: 934 * 0 on success 935 * -EFAULT on error reading the location 936 * -EINVAL on a failed compare of the contents 937 * -EPERM on error writing to the location 938 * Any other value will be considered a failure. 939 */ 940 extern int ftrace_make_nop(struct module *mod, 941 struct dyn_ftrace *rec, unsigned long addr); 942 943 /** 944 * ftrace_need_init_nop - return whether nop call sites should be initialized 945 * 946 * Normally the compiler's -mnop-mcount generates suitable nops, so we don't 947 * need to call ftrace_init_nop() if the code is built with that flag. 948 * Architectures where this is not always the case may define their own 949 * condition. 950 * 951 * Return must be: 952 * 0 if ftrace_init_nop() should be called 953 * Nonzero if ftrace_init_nop() should not be called 954 */ 955 956 #ifndef ftrace_need_init_nop 957 #define ftrace_need_init_nop() (!__is_defined(CC_USING_NOP_MCOUNT)) 958 #endif 959 960 /** 961 * ftrace_init_nop - initialize a nop call site 962 * @mod: module structure if called by module load initialization 963 * @rec: the call site record (e.g. mcount/fentry) 964 * 965 * This is a very sensitive operation and great care needs 966 * to be taken by the arch. The operation should carefully 967 * read the location, check to see if what is read is indeed 968 * what we expect it to be, and then on success of the compare, 969 * it should write to the location. 970 * 971 * The code segment at @rec->ip should contain the contents created by 972 * the compiler 973 * 974 * Return must be: 975 * 0 on success 976 * -EFAULT on error reading the location 977 * -EINVAL on a failed compare of the contents 978 * -EPERM on error writing to the location 979 * Any other value will be considered a failure. 980 */ 981 #ifndef ftrace_init_nop 982 static inline int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) 983 { 984 return ftrace_make_nop(mod, rec, MCOUNT_ADDR); 985 } 986 #endif 987 988 /** 989 * ftrace_make_call - convert a nop call site into a call to addr 990 * @rec: the call site record (e.g. mcount/fentry) 991 * @addr: the address that the call site should call 992 * 993 * This is a very sensitive operation and great care needs 994 * to be taken by the arch. The operation should carefully 995 * read the location, check to see if what is read is indeed 996 * what we expect it to be, and then on success of the compare, 997 * it should write to the location. 998 * 999 * The code segment at @rec->ip should be a nop 1000 * 1001 * Return must be: 1002 * 0 on success 1003 * -EFAULT on error reading the location 1004 * -EINVAL on a failed compare of the contents 1005 * -EPERM on error writing to the location 1006 * Any other value will be considered a failure. 1007 */ 1008 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr); 1009 1010 #if defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS) || \ 1011 defined(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS) || \ 1012 defined(CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS) 1013 /** 1014 * ftrace_modify_call - convert from one addr to another (no nop) 1015 * @rec: the call site record (e.g. mcount/fentry) 1016 * @old_addr: the address expected to be currently called to 1017 * @addr: the address to change to 1018 * 1019 * This is a very sensitive operation and great care needs 1020 * to be taken by the arch. The operation should carefully 1021 * read the location, check to see if what is read is indeed 1022 * what we expect it to be, and then on success of the compare, 1023 * it should write to the location. 1024 * 1025 * When using call ops, this is called when the associated ops change, even 1026 * when (addr == old_addr). 1027 * 1028 * The code segment at @rec->ip should be a caller to @old_addr 1029 * 1030 * Return must be: 1031 * 0 on success 1032 * -EFAULT on error reading the location 1033 * -EINVAL on a failed compare of the contents 1034 * -EPERM on error writing to the location 1035 * Any other value will be considered a failure. 1036 */ 1037 extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, 1038 unsigned long addr); 1039 #else 1040 /* Should never be called */ 1041 static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, 1042 unsigned long addr) 1043 { 1044 return -EINVAL; 1045 } 1046 #endif 1047 1048 extern int skip_trace(unsigned long ip); 1049 extern void ftrace_module_init(struct module *mod); 1050 extern void ftrace_module_enable(struct module *mod); 1051 extern void ftrace_release_mod(struct module *mod); 1052 #else /* CONFIG_DYNAMIC_FTRACE */ 1053 static inline int skip_trace(unsigned long ip) { return 0; } 1054 static inline void ftrace_module_init(struct module *mod) { } 1055 static inline void ftrace_module_enable(struct module *mod) { } 1056 static inline void ftrace_release_mod(struct module *mod) { } 1057 static inline int ftrace_text_reserved(const void *start, const void *end) 1058 { 1059 return 0; 1060 } 1061 static inline unsigned long ftrace_location(unsigned long ip) 1062 { 1063 return 0; 1064 } 1065 1066 /* 1067 * Again users of functions that have ftrace_ops may not 1068 * have them defined when ftrace is not enabled, but these 1069 * functions may still be called. Use a macro instead of inline. 1070 */ 1071 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; }) 1072 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0) 1073 #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; }) 1074 #define ftrace_set_filter_ips(ops, ips, cnt, remove, reset) ({ -ENODEV; }) 1075 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; }) 1076 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; }) 1077 #define ftrace_free_filter(ops) do { } while (0) 1078 #define ftrace_ops_set_global_filter(ops) do { } while (0) 1079 1080 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf, 1081 size_t cnt, loff_t *ppos) { return -ENODEV; } 1082 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf, 1083 size_t cnt, loff_t *ppos) { return -ENODEV; } 1084 static inline int 1085 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; } 1086 1087 static inline bool is_ftrace_trampoline(unsigned long addr) 1088 { 1089 return false; 1090 } 1091 #endif /* CONFIG_DYNAMIC_FTRACE */ 1092 1093 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 1094 #ifndef ftrace_graph_func 1095 #define ftrace_graph_func ftrace_stub 1096 #define FTRACE_OPS_GRAPH_STUB FTRACE_OPS_FL_STUB 1097 #else 1098 #define FTRACE_OPS_GRAPH_STUB 0 1099 #endif 1100 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 1101 1102 /* totally disable ftrace - can not re-enable after this */ 1103 void ftrace_kill(void); 1104 1105 static inline void tracer_disable(void) 1106 { 1107 #ifdef CONFIG_FUNCTION_TRACER 1108 ftrace_enabled = 0; 1109 #endif 1110 } 1111 1112 /* 1113 * Ftrace disable/restore without lock. Some synchronization mechanism 1114 * must be used to prevent ftrace_enabled to be changed between 1115 * disable/restore. 1116 */ 1117 static inline int __ftrace_enabled_save(void) 1118 { 1119 #ifdef CONFIG_FUNCTION_TRACER 1120 int saved_ftrace_enabled = ftrace_enabled; 1121 ftrace_enabled = 0; 1122 return saved_ftrace_enabled; 1123 #else 1124 return 0; 1125 #endif 1126 } 1127 1128 static inline void __ftrace_enabled_restore(int enabled) 1129 { 1130 #ifdef CONFIG_FUNCTION_TRACER 1131 ftrace_enabled = enabled; 1132 #endif 1133 } 1134 1135 /* All archs should have this, but we define it for consistency */ 1136 #ifndef ftrace_return_address0 1137 # define ftrace_return_address0 __builtin_return_address(0) 1138 #endif 1139 1140 /* Archs may use other ways for ADDR1 and beyond */ 1141 #ifndef ftrace_return_address 1142 # ifdef CONFIG_FRAME_POINTER 1143 # define ftrace_return_address(n) __builtin_return_address(n) 1144 # else 1145 # define ftrace_return_address(n) 0UL 1146 # endif 1147 #endif 1148 1149 #define CALLER_ADDR0 ((unsigned long)ftrace_return_address0) 1150 #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1)) 1151 #define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2)) 1152 #define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3)) 1153 #define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4)) 1154 #define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5)) 1155 #define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6)) 1156 1157 static __always_inline unsigned long get_lock_parent_ip(void) 1158 { 1159 unsigned long addr = CALLER_ADDR0; 1160 1161 if (!in_lock_functions(addr)) 1162 return addr; 1163 addr = CALLER_ADDR1; 1164 if (!in_lock_functions(addr)) 1165 return addr; 1166 return CALLER_ADDR2; 1167 } 1168 1169 #ifdef CONFIG_TRACE_PREEMPT_TOGGLE 1170 extern void trace_preempt_on(unsigned long a0, unsigned long a1); 1171 extern void trace_preempt_off(unsigned long a0, unsigned long a1); 1172 #else 1173 /* 1174 * Use defines instead of static inlines because some arches will make code out 1175 * of the CALLER_ADDR, when we really want these to be a real nop. 1176 */ 1177 # define trace_preempt_on(a0, a1) do { } while (0) 1178 # define trace_preempt_off(a0, a1) do { } while (0) 1179 #endif 1180 1181 #ifdef CONFIG_DYNAMIC_FTRACE 1182 extern void ftrace_init(void); 1183 #ifdef CC_USING_PATCHABLE_FUNCTION_ENTRY 1184 #define FTRACE_CALLSITE_SECTION "__patchable_function_entries" 1185 #else 1186 #define FTRACE_CALLSITE_SECTION "__mcount_loc" 1187 #endif 1188 #else 1189 static inline void ftrace_init(void) { } 1190 #endif 1191 1192 /* 1193 * Structure that defines an entry function trace. 1194 * It's already packed but the attribute "packed" is needed 1195 * to remove extra padding at the end. 1196 */ 1197 struct ftrace_graph_ent { 1198 unsigned long func; /* Current function */ 1199 long depth; /* signed to check for less than zero */ 1200 } __packed; 1201 1202 /* 1203 * Structure that defines an entry function trace with retaddr. 1204 */ 1205 struct fgraph_retaddr_ent { 1206 struct ftrace_graph_ent ent; 1207 unsigned long retaddr; /* Return address */ 1208 } __packed; 1209 1210 /* 1211 * Structure that defines a return 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_ret { 1216 unsigned long func; /* Current function */ 1217 #ifdef CONFIG_FUNCTION_GRAPH_RETVAL 1218 unsigned long retval; 1219 #endif 1220 int depth; 1221 /* Number of functions that overran the depth limit for current task */ 1222 unsigned int overrun; 1223 } __packed; 1224 1225 struct fgraph_ops; 1226 1227 /* Type of the callback handlers for tracing function graph*/ 1228 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *, 1229 struct fgraph_ops *, 1230 struct ftrace_regs *); /* return */ 1231 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *, 1232 struct fgraph_ops *, 1233 struct ftrace_regs *); /* entry */ 1234 1235 extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace, 1236 struct fgraph_ops *gops, 1237 struct ftrace_regs *fregs); 1238 bool ftrace_pids_enabled(struct ftrace_ops *ops); 1239 1240 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 1241 1242 struct fgraph_ops { 1243 trace_func_graph_ent_t entryfunc; 1244 trace_func_graph_ret_t retfunc; 1245 struct ftrace_ops ops; /* for the hash lists */ 1246 void *private; 1247 trace_func_graph_ent_t saved_func; 1248 int idx; 1249 }; 1250 1251 void *fgraph_reserve_data(int idx, int size_bytes); 1252 void *fgraph_retrieve_data(int idx, int *size_bytes); 1253 void *fgraph_retrieve_parent_data(int idx, int *size_bytes, int depth); 1254 1255 /* 1256 * Stack of return addresses for functions 1257 * of a thread. 1258 * Used in struct thread_info 1259 */ 1260 struct ftrace_ret_stack { 1261 unsigned long ret; 1262 unsigned long func; 1263 #ifdef HAVE_FUNCTION_GRAPH_FP_TEST 1264 unsigned long fp; 1265 #endif 1266 unsigned long *retp; 1267 }; 1268 1269 /* 1270 * Primary handler of a function return. 1271 * It relays on ftrace_return_to_handler. 1272 * Defined in entry_32/64.S 1273 */ 1274 extern void return_to_handler(void); 1275 1276 extern int 1277 function_graph_enter_regs(unsigned long ret, unsigned long func, 1278 unsigned long frame_pointer, unsigned long *retp, 1279 struct ftrace_regs *fregs); 1280 1281 static inline int function_graph_enter(unsigned long ret, unsigned long func, 1282 unsigned long fp, unsigned long *retp) 1283 { 1284 return function_graph_enter_regs(ret, func, fp, retp, NULL); 1285 } 1286 1287 struct ftrace_ret_stack * 1288 ftrace_graph_get_ret_stack(struct task_struct *task, int skip); 1289 unsigned long ftrace_graph_top_ret_addr(struct task_struct *task); 1290 1291 unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx, 1292 unsigned long ret, unsigned long *retp); 1293 unsigned long *fgraph_get_task_var(struct fgraph_ops *gops); 1294 1295 /* 1296 * Sometimes we don't want to trace a function with the function 1297 * graph tracer but we want them to keep traced by the usual function 1298 * tracer if the function graph tracer is not configured. 1299 */ 1300 #define __notrace_funcgraph notrace 1301 1302 #define FTRACE_RETFUNC_DEPTH 50 1303 #define FTRACE_RETSTACK_ALLOC_SIZE 32 1304 1305 extern int register_ftrace_graph(struct fgraph_ops *ops); 1306 extern void unregister_ftrace_graph(struct fgraph_ops *ops); 1307 1308 /** 1309 * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called 1310 * 1311 * ftrace_graph_stop() is called when a severe error is detected in 1312 * the function graph tracing. This function is called by the critical 1313 * paths of function graph to keep those paths from doing any more harm. 1314 */ 1315 DECLARE_STATIC_KEY_FALSE(kill_ftrace_graph); 1316 1317 static inline bool ftrace_graph_is_dead(void) 1318 { 1319 return static_branch_unlikely(&kill_ftrace_graph); 1320 } 1321 1322 extern void ftrace_graph_stop(void); 1323 1324 /* The current handlers in use */ 1325 extern trace_func_graph_ret_t ftrace_graph_return; 1326 extern trace_func_graph_ent_t ftrace_graph_entry; 1327 1328 extern void ftrace_graph_init_task(struct task_struct *t); 1329 extern void ftrace_graph_exit_task(struct task_struct *t); 1330 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu); 1331 1332 /* Used by assembly, but to quiet sparse warnings */ 1333 extern struct ftrace_ops *function_trace_op; 1334 1335 static inline void pause_graph_tracing(void) 1336 { 1337 atomic_inc(¤t->tracing_graph_pause); 1338 } 1339 1340 static inline void unpause_graph_tracing(void) 1341 { 1342 atomic_dec(¤t->tracing_graph_pause); 1343 } 1344 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */ 1345 1346 #define __notrace_funcgraph 1347 1348 static inline void ftrace_graph_init_task(struct task_struct *t) { } 1349 static inline void ftrace_graph_exit_task(struct task_struct *t) { } 1350 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { } 1351 1352 /* Define as macros as fgraph_ops may not be defined */ 1353 #define register_ftrace_graph(ops) ({ -1; }) 1354 #define unregister_ftrace_graph(ops) do { } while (0) 1355 1356 static inline unsigned long 1357 ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret, 1358 unsigned long *retp) 1359 { 1360 return ret; 1361 } 1362 1363 static inline void pause_graph_tracing(void) { } 1364 static inline void unpause_graph_tracing(void) { } 1365 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 1366 1367 #ifdef CONFIG_TRACING 1368 enum ftrace_dump_mode; 1369 1370 extern int ftrace_dump_on_oops_enabled(void); 1371 1372 extern void disable_trace_on_warning(void); 1373 1374 #else /* CONFIG_TRACING */ 1375 static inline void disable_trace_on_warning(void) { } 1376 #endif /* CONFIG_TRACING */ 1377 1378 #ifdef CONFIG_FTRACE_SYSCALLS 1379 1380 unsigned long arch_syscall_addr(int nr); 1381 1382 #endif /* CONFIG_FTRACE_SYSCALLS */ 1383 1384 #endif /* _LINUX_FTRACE_H */ 1385