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