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