1 #ifndef _LINUX_KERNEL_TRACE_H 2 #define _LINUX_KERNEL_TRACE_H 3 4 #include <linux/fs.h> 5 #include <asm/atomic.h> 6 #include <linux/sched.h> 7 #include <linux/clocksource.h> 8 #include <linux/ring_buffer.h> 9 #include <linux/mmiotrace.h> 10 #include <linux/tracepoint.h> 11 #include <linux/ftrace.h> 12 #include <trace/boot.h> 13 #include <linux/kmemtrace.h> 14 #include <linux/hw_breakpoint.h> 15 16 #include <linux/trace_seq.h> 17 #include <linux/ftrace_event.h> 18 19 enum trace_type { 20 __TRACE_FIRST_TYPE = 0, 21 22 TRACE_FN, 23 TRACE_CTX, 24 TRACE_WAKE, 25 TRACE_STACK, 26 TRACE_PRINT, 27 TRACE_BPRINT, 28 TRACE_SPECIAL, 29 TRACE_MMIO_RW, 30 TRACE_MMIO_MAP, 31 TRACE_BRANCH, 32 TRACE_BOOT_CALL, 33 TRACE_BOOT_RET, 34 TRACE_GRAPH_RET, 35 TRACE_GRAPH_ENT, 36 TRACE_USER_STACK, 37 TRACE_KMEM_ALLOC, 38 TRACE_KMEM_FREE, 39 TRACE_BLK, 40 TRACE_KSYM, 41 42 __TRACE_LAST_TYPE, 43 }; 44 45 enum kmemtrace_type_id { 46 KMEMTRACE_TYPE_KMALLOC = 0, /* kmalloc() or kfree(). */ 47 KMEMTRACE_TYPE_CACHE, /* kmem_cache_*(). */ 48 KMEMTRACE_TYPE_PAGES, /* __get_free_pages() and friends. */ 49 }; 50 51 extern struct tracer boot_tracer; 52 53 #undef __field 54 #define __field(type, item) type item; 55 56 #undef __field_struct 57 #define __field_struct(type, item) __field(type, item) 58 59 #undef __field_desc 60 #define __field_desc(type, container, item) 61 62 #undef __array 63 #define __array(type, item, size) type item[size]; 64 65 #undef __array_desc 66 #define __array_desc(type, container, item, size) 67 68 #undef __dynamic_array 69 #define __dynamic_array(type, item) type item[]; 70 71 #undef F_STRUCT 72 #define F_STRUCT(args...) args 73 74 #undef FTRACE_ENTRY 75 #define FTRACE_ENTRY(name, struct_name, id, tstruct, print) \ 76 struct struct_name { \ 77 struct trace_entry ent; \ 78 tstruct \ 79 } 80 81 #undef TP_ARGS 82 #define TP_ARGS(args...) args 83 84 #undef FTRACE_ENTRY_DUP 85 #define FTRACE_ENTRY_DUP(name, name_struct, id, tstruct, printk) 86 87 #include "trace_entries.h" 88 89 /* 90 * syscalls are special, and need special handling, this is why 91 * they are not included in trace_entries.h 92 */ 93 struct syscall_trace_enter { 94 struct trace_entry ent; 95 int nr; 96 unsigned long args[]; 97 }; 98 99 struct syscall_trace_exit { 100 struct trace_entry ent; 101 int nr; 102 long ret; 103 }; 104 105 struct kprobe_trace_entry_head { 106 struct trace_entry ent; 107 unsigned long ip; 108 }; 109 110 struct kretprobe_trace_entry_head { 111 struct trace_entry ent; 112 unsigned long func; 113 unsigned long ret_ip; 114 }; 115 116 /* 117 * trace_flag_type is an enumeration that holds different 118 * states when a trace occurs. These are: 119 * IRQS_OFF - interrupts were disabled 120 * IRQS_NOSUPPORT - arch does not support irqs_disabled_flags 121 * NEED_RESCHED - reschedule is requested 122 * HARDIRQ - inside an interrupt handler 123 * SOFTIRQ - inside a softirq handler 124 */ 125 enum trace_flag_type { 126 TRACE_FLAG_IRQS_OFF = 0x01, 127 TRACE_FLAG_IRQS_NOSUPPORT = 0x02, 128 TRACE_FLAG_NEED_RESCHED = 0x04, 129 TRACE_FLAG_HARDIRQ = 0x08, 130 TRACE_FLAG_SOFTIRQ = 0x10, 131 }; 132 133 #define TRACE_BUF_SIZE 1024 134 135 /* 136 * The CPU trace array - it consists of thousands of trace entries 137 * plus some other descriptor data: (for example which task started 138 * the trace, etc.) 139 */ 140 struct trace_array_cpu { 141 atomic_t disabled; 142 void *buffer_page; /* ring buffer spare */ 143 144 unsigned long saved_latency; 145 unsigned long critical_start; 146 unsigned long critical_end; 147 unsigned long critical_sequence; 148 unsigned long nice; 149 unsigned long policy; 150 unsigned long rt_priority; 151 unsigned long skipped_entries; 152 cycle_t preempt_timestamp; 153 pid_t pid; 154 uid_t uid; 155 char comm[TASK_COMM_LEN]; 156 }; 157 158 /* 159 * The trace array - an array of per-CPU trace arrays. This is the 160 * highest level data structure that individual tracers deal with. 161 * They have on/off state as well: 162 */ 163 struct trace_array { 164 struct ring_buffer *buffer; 165 unsigned long entries; 166 int cpu; 167 cycle_t time_start; 168 struct task_struct *waiter; 169 struct trace_array_cpu *data[NR_CPUS]; 170 }; 171 172 #define FTRACE_CMP_TYPE(var, type) \ 173 __builtin_types_compatible_p(typeof(var), type *) 174 175 #undef IF_ASSIGN 176 #define IF_ASSIGN(var, entry, etype, id) \ 177 if (FTRACE_CMP_TYPE(var, etype)) { \ 178 var = (typeof(var))(entry); \ 179 WARN_ON(id && (entry)->type != id); \ 180 break; \ 181 } 182 183 /* Will cause compile errors if type is not found. */ 184 extern void __ftrace_bad_type(void); 185 186 /* 187 * The trace_assign_type is a verifier that the entry type is 188 * the same as the type being assigned. To add new types simply 189 * add a line with the following format: 190 * 191 * IF_ASSIGN(var, ent, type, id); 192 * 193 * Where "type" is the trace type that includes the trace_entry 194 * as the "ent" item. And "id" is the trace identifier that is 195 * used in the trace_type enum. 196 * 197 * If the type can have more than one id, then use zero. 198 */ 199 #define trace_assign_type(var, ent) \ 200 do { \ 201 IF_ASSIGN(var, ent, struct ftrace_entry, TRACE_FN); \ 202 IF_ASSIGN(var, ent, struct ctx_switch_entry, 0); \ 203 IF_ASSIGN(var, ent, struct stack_entry, TRACE_STACK); \ 204 IF_ASSIGN(var, ent, struct userstack_entry, TRACE_USER_STACK);\ 205 IF_ASSIGN(var, ent, struct print_entry, TRACE_PRINT); \ 206 IF_ASSIGN(var, ent, struct bprint_entry, TRACE_BPRINT); \ 207 IF_ASSIGN(var, ent, struct special_entry, 0); \ 208 IF_ASSIGN(var, ent, struct trace_mmiotrace_rw, \ 209 TRACE_MMIO_RW); \ 210 IF_ASSIGN(var, ent, struct trace_mmiotrace_map, \ 211 TRACE_MMIO_MAP); \ 212 IF_ASSIGN(var, ent, struct trace_boot_call, TRACE_BOOT_CALL);\ 213 IF_ASSIGN(var, ent, struct trace_boot_ret, TRACE_BOOT_RET);\ 214 IF_ASSIGN(var, ent, struct trace_branch, TRACE_BRANCH); \ 215 IF_ASSIGN(var, ent, struct ftrace_graph_ent_entry, \ 216 TRACE_GRAPH_ENT); \ 217 IF_ASSIGN(var, ent, struct ftrace_graph_ret_entry, \ 218 TRACE_GRAPH_RET); \ 219 IF_ASSIGN(var, ent, struct kmemtrace_alloc_entry, \ 220 TRACE_KMEM_ALLOC); \ 221 IF_ASSIGN(var, ent, struct kmemtrace_free_entry, \ 222 TRACE_KMEM_FREE); \ 223 IF_ASSIGN(var, ent, struct ksym_trace_entry, TRACE_KSYM);\ 224 __ftrace_bad_type(); \ 225 } while (0) 226 227 /* 228 * An option specific to a tracer. This is a boolean value. 229 * The bit is the bit index that sets its value on the 230 * flags value in struct tracer_flags. 231 */ 232 struct tracer_opt { 233 const char *name; /* Will appear on the trace_options file */ 234 u32 bit; /* Mask assigned in val field in tracer_flags */ 235 }; 236 237 /* 238 * The set of specific options for a tracer. Your tracer 239 * have to set the initial value of the flags val. 240 */ 241 struct tracer_flags { 242 u32 val; 243 struct tracer_opt *opts; 244 }; 245 246 /* Makes more easy to define a tracer opt */ 247 #define TRACER_OPT(s, b) .name = #s, .bit = b 248 249 250 /** 251 * struct tracer - a specific tracer and its callbacks to interact with debugfs 252 * @name: the name chosen to select it on the available_tracers file 253 * @init: called when one switches to this tracer (echo name > current_tracer) 254 * @reset: called when one switches to another tracer 255 * @start: called when tracing is unpaused (echo 1 > tracing_enabled) 256 * @stop: called when tracing is paused (echo 0 > tracing_enabled) 257 * @open: called when the trace file is opened 258 * @pipe_open: called when the trace_pipe file is opened 259 * @wait_pipe: override how the user waits for traces on trace_pipe 260 * @close: called when the trace file is released 261 * @pipe_close: called when the trace_pipe file is released 262 * @read: override the default read callback on trace_pipe 263 * @splice_read: override the default splice_read callback on trace_pipe 264 * @selftest: selftest to run on boot (see trace_selftest.c) 265 * @print_headers: override the first lines that describe your columns 266 * @print_line: callback that prints a trace 267 * @set_flag: signals one of your private flags changed (trace_options file) 268 * @flags: your private flags 269 */ 270 struct tracer { 271 const char *name; 272 int (*init)(struct trace_array *tr); 273 void (*reset)(struct trace_array *tr); 274 void (*start)(struct trace_array *tr); 275 void (*stop)(struct trace_array *tr); 276 void (*open)(struct trace_iterator *iter); 277 void (*pipe_open)(struct trace_iterator *iter); 278 void (*wait_pipe)(struct trace_iterator *iter); 279 void (*close)(struct trace_iterator *iter); 280 void (*pipe_close)(struct trace_iterator *iter); 281 ssize_t (*read)(struct trace_iterator *iter, 282 struct file *filp, char __user *ubuf, 283 size_t cnt, loff_t *ppos); 284 ssize_t (*splice_read)(struct trace_iterator *iter, 285 struct file *filp, 286 loff_t *ppos, 287 struct pipe_inode_info *pipe, 288 size_t len, 289 unsigned int flags); 290 #ifdef CONFIG_FTRACE_STARTUP_TEST 291 int (*selftest)(struct tracer *trace, 292 struct trace_array *tr); 293 #endif 294 void (*print_header)(struct seq_file *m); 295 enum print_line_t (*print_line)(struct trace_iterator *iter); 296 /* If you handled the flag setting, return 0 */ 297 int (*set_flag)(u32 old_flags, u32 bit, int set); 298 struct tracer *next; 299 int print_max; 300 struct tracer_flags *flags; 301 }; 302 303 304 #define TRACE_PIPE_ALL_CPU -1 305 306 int tracer_init(struct tracer *t, struct trace_array *tr); 307 int tracing_is_enabled(void); 308 void trace_wake_up(void); 309 void tracing_reset(struct trace_array *tr, int cpu); 310 void tracing_reset_online_cpus(struct trace_array *tr); 311 void tracing_reset_current(int cpu); 312 void tracing_reset_current_online_cpus(void); 313 int tracing_open_generic(struct inode *inode, struct file *filp); 314 struct dentry *trace_create_file(const char *name, 315 mode_t mode, 316 struct dentry *parent, 317 void *data, 318 const struct file_operations *fops); 319 320 struct dentry *tracing_init_dentry(void); 321 void init_tracer_sysprof_debugfs(struct dentry *d_tracer); 322 323 struct ring_buffer_event; 324 325 struct ring_buffer_event * 326 trace_buffer_lock_reserve(struct ring_buffer *buffer, 327 int type, 328 unsigned long len, 329 unsigned long flags, 330 int pc); 331 void trace_buffer_unlock_commit(struct ring_buffer *buffer, 332 struct ring_buffer_event *event, 333 unsigned long flags, int pc); 334 335 struct trace_entry *tracing_get_trace_entry(struct trace_array *tr, 336 struct trace_array_cpu *data); 337 338 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter, 339 int *ent_cpu, u64 *ent_ts); 340 341 void default_wait_pipe(struct trace_iterator *iter); 342 void poll_wait_pipe(struct trace_iterator *iter); 343 344 void ftrace(struct trace_array *tr, 345 struct trace_array_cpu *data, 346 unsigned long ip, 347 unsigned long parent_ip, 348 unsigned long flags, int pc); 349 void tracing_sched_switch_trace(struct trace_array *tr, 350 struct task_struct *prev, 351 struct task_struct *next, 352 unsigned long flags, int pc); 353 354 void tracing_sched_wakeup_trace(struct trace_array *tr, 355 struct task_struct *wakee, 356 struct task_struct *cur, 357 unsigned long flags, int pc); 358 void trace_special(struct trace_array *tr, 359 struct trace_array_cpu *data, 360 unsigned long arg1, 361 unsigned long arg2, 362 unsigned long arg3, int pc); 363 void trace_function(struct trace_array *tr, 364 unsigned long ip, 365 unsigned long parent_ip, 366 unsigned long flags, int pc); 367 void trace_default_header(struct seq_file *m); 368 void print_trace_header(struct seq_file *m, struct trace_iterator *iter); 369 int trace_empty(struct trace_iterator *iter); 370 371 void trace_graph_return(struct ftrace_graph_ret *trace); 372 int trace_graph_entry(struct ftrace_graph_ent *trace); 373 void set_graph_array(struct trace_array *tr); 374 375 void tracing_start_cmdline_record(void); 376 void tracing_stop_cmdline_record(void); 377 void tracing_sched_switch_assign_trace(struct trace_array *tr); 378 void tracing_stop_sched_switch_record(void); 379 void tracing_start_sched_switch_record(void); 380 int register_tracer(struct tracer *type); 381 void unregister_tracer(struct tracer *type); 382 int is_tracing_stopped(void); 383 384 extern int process_new_ksym_entry(char *ksymname, int op, unsigned long addr); 385 386 extern unsigned long nsecs_to_usecs(unsigned long nsecs); 387 388 extern unsigned long tracing_thresh; 389 390 #ifdef CONFIG_TRACER_MAX_TRACE 391 extern unsigned long tracing_max_latency; 392 393 void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu); 394 void update_max_tr_single(struct trace_array *tr, 395 struct task_struct *tsk, int cpu); 396 #endif /* CONFIG_TRACER_MAX_TRACE */ 397 398 #ifdef CONFIG_STACKTRACE 399 void ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags, 400 int skip, int pc); 401 402 void ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, 403 int pc); 404 405 void __trace_stack(struct trace_array *tr, unsigned long flags, int skip, 406 int pc); 407 #else 408 static inline void ftrace_trace_stack(struct trace_array *tr, 409 unsigned long flags, int skip, int pc) 410 { 411 } 412 413 static inline void ftrace_trace_userstack(struct trace_array *tr, 414 unsigned long flags, int pc) 415 { 416 } 417 418 static inline void __trace_stack(struct trace_array *tr, unsigned long flags, 419 int skip, int pc) 420 { 421 } 422 #endif /* CONFIG_STACKTRACE */ 423 424 extern cycle_t ftrace_now(int cpu); 425 426 extern void trace_find_cmdline(int pid, char comm[]); 427 428 #ifdef CONFIG_DYNAMIC_FTRACE 429 extern unsigned long ftrace_update_tot_cnt; 430 #define DYN_FTRACE_TEST_NAME trace_selftest_dynamic_test_func 431 extern int DYN_FTRACE_TEST_NAME(void); 432 #endif 433 434 extern int ring_buffer_expanded; 435 extern bool tracing_selftest_disabled; 436 DECLARE_PER_CPU(int, ftrace_cpu_disabled); 437 438 #ifdef CONFIG_FTRACE_STARTUP_TEST 439 extern int trace_selftest_startup_function(struct tracer *trace, 440 struct trace_array *tr); 441 extern int trace_selftest_startup_function_graph(struct tracer *trace, 442 struct trace_array *tr); 443 extern int trace_selftest_startup_irqsoff(struct tracer *trace, 444 struct trace_array *tr); 445 extern int trace_selftest_startup_preemptoff(struct tracer *trace, 446 struct trace_array *tr); 447 extern int trace_selftest_startup_preemptirqsoff(struct tracer *trace, 448 struct trace_array *tr); 449 extern int trace_selftest_startup_wakeup(struct tracer *trace, 450 struct trace_array *tr); 451 extern int trace_selftest_startup_nop(struct tracer *trace, 452 struct trace_array *tr); 453 extern int trace_selftest_startup_sched_switch(struct tracer *trace, 454 struct trace_array *tr); 455 extern int trace_selftest_startup_sysprof(struct tracer *trace, 456 struct trace_array *tr); 457 extern int trace_selftest_startup_branch(struct tracer *trace, 458 struct trace_array *tr); 459 extern int trace_selftest_startup_ksym(struct tracer *trace, 460 struct trace_array *tr); 461 #endif /* CONFIG_FTRACE_STARTUP_TEST */ 462 463 extern void *head_page(struct trace_array_cpu *data); 464 extern unsigned long long ns2usecs(cycle_t nsec); 465 extern int 466 trace_vbprintk(unsigned long ip, const char *fmt, va_list args); 467 extern int 468 trace_vprintk(unsigned long ip, const char *fmt, va_list args); 469 extern int 470 trace_array_vprintk(struct trace_array *tr, 471 unsigned long ip, const char *fmt, va_list args); 472 int trace_array_printk(struct trace_array *tr, 473 unsigned long ip, const char *fmt, ...); 474 475 extern unsigned long trace_flags; 476 477 extern int trace_clock_id; 478 479 /* Standard output formatting function used for function return traces */ 480 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 481 482 /* Flag options */ 483 #define TRACE_GRAPH_PRINT_OVERRUN 0x1 484 #define TRACE_GRAPH_PRINT_CPU 0x2 485 #define TRACE_GRAPH_PRINT_OVERHEAD 0x4 486 #define TRACE_GRAPH_PRINT_PROC 0x8 487 #define TRACE_GRAPH_PRINT_DURATION 0x10 488 #define TRACE_GRAPH_PRINT_ABS_TIME 0x20 489 490 extern enum print_line_t 491 print_graph_function_flags(struct trace_iterator *iter, u32 flags); 492 extern void print_graph_headers_flags(struct seq_file *s, u32 flags); 493 extern enum print_line_t 494 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s); 495 extern void graph_trace_open(struct trace_iterator *iter); 496 extern void graph_trace_close(struct trace_iterator *iter); 497 extern int __trace_graph_entry(struct trace_array *tr, 498 struct ftrace_graph_ent *trace, 499 unsigned long flags, int pc); 500 extern void __trace_graph_return(struct trace_array *tr, 501 struct ftrace_graph_ret *trace, 502 unsigned long flags, int pc); 503 504 505 #ifdef CONFIG_DYNAMIC_FTRACE 506 /* TODO: make this variable */ 507 #define FTRACE_GRAPH_MAX_FUNCS 32 508 extern int ftrace_graph_filter_enabled; 509 extern int ftrace_graph_count; 510 extern unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS]; 511 512 static inline int ftrace_graph_addr(unsigned long addr) 513 { 514 int i; 515 516 if (!ftrace_graph_filter_enabled) 517 return 1; 518 519 for (i = 0; i < ftrace_graph_count; i++) { 520 if (addr == ftrace_graph_funcs[i]) 521 return 1; 522 } 523 524 return 0; 525 } 526 #else 527 static inline int ftrace_graph_addr(unsigned long addr) 528 { 529 return 1; 530 } 531 #endif /* CONFIG_DYNAMIC_FTRACE */ 532 #else /* CONFIG_FUNCTION_GRAPH_TRACER */ 533 static inline enum print_line_t 534 print_graph_function_flags(struct trace_iterator *iter, u32 flags) 535 { 536 return TRACE_TYPE_UNHANDLED; 537 } 538 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 539 540 extern struct list_head ftrace_pids; 541 542 #ifdef CONFIG_FUNCTION_TRACER 543 static inline int ftrace_trace_task(struct task_struct *task) 544 { 545 if (list_empty(&ftrace_pids)) 546 return 1; 547 548 return test_tsk_trace_trace(task); 549 } 550 #else 551 static inline int ftrace_trace_task(struct task_struct *task) 552 { 553 return 1; 554 } 555 #endif 556 557 /* 558 * struct trace_parser - servers for reading the user input separated by spaces 559 * @cont: set if the input is not complete - no final space char was found 560 * @buffer: holds the parsed user input 561 * @idx: user input length 562 * @size: buffer size 563 */ 564 struct trace_parser { 565 bool cont; 566 char *buffer; 567 unsigned idx; 568 unsigned size; 569 }; 570 571 static inline bool trace_parser_loaded(struct trace_parser *parser) 572 { 573 return (parser->idx != 0); 574 } 575 576 static inline bool trace_parser_cont(struct trace_parser *parser) 577 { 578 return parser->cont; 579 } 580 581 static inline void trace_parser_clear(struct trace_parser *parser) 582 { 583 parser->cont = false; 584 parser->idx = 0; 585 } 586 587 extern int trace_parser_get_init(struct trace_parser *parser, int size); 588 extern void trace_parser_put(struct trace_parser *parser); 589 extern int trace_get_user(struct trace_parser *parser, const char __user *ubuf, 590 size_t cnt, loff_t *ppos); 591 592 /* 593 * trace_iterator_flags is an enumeration that defines bit 594 * positions into trace_flags that controls the output. 595 * 596 * NOTE: These bits must match the trace_options array in 597 * trace.c. 598 */ 599 enum trace_iterator_flags { 600 TRACE_ITER_PRINT_PARENT = 0x01, 601 TRACE_ITER_SYM_OFFSET = 0x02, 602 TRACE_ITER_SYM_ADDR = 0x04, 603 TRACE_ITER_VERBOSE = 0x08, 604 TRACE_ITER_RAW = 0x10, 605 TRACE_ITER_HEX = 0x20, 606 TRACE_ITER_BIN = 0x40, 607 TRACE_ITER_BLOCK = 0x80, 608 TRACE_ITER_STACKTRACE = 0x100, 609 TRACE_ITER_PRINTK = 0x200, 610 TRACE_ITER_PREEMPTONLY = 0x400, 611 TRACE_ITER_BRANCH = 0x800, 612 TRACE_ITER_ANNOTATE = 0x1000, 613 TRACE_ITER_USERSTACKTRACE = 0x2000, 614 TRACE_ITER_SYM_USEROBJ = 0x4000, 615 TRACE_ITER_PRINTK_MSGONLY = 0x8000, 616 TRACE_ITER_CONTEXT_INFO = 0x10000, /* Print pid/cpu/time */ 617 TRACE_ITER_LATENCY_FMT = 0x20000, 618 TRACE_ITER_SLEEP_TIME = 0x40000, 619 TRACE_ITER_GRAPH_TIME = 0x80000, 620 }; 621 622 /* 623 * TRACE_ITER_SYM_MASK masks the options in trace_flags that 624 * control the output of kernel symbols. 625 */ 626 #define TRACE_ITER_SYM_MASK \ 627 (TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR) 628 629 extern struct tracer nop_trace; 630 631 /** 632 * ftrace_preempt_disable - disable preemption scheduler safe 633 * 634 * When tracing can happen inside the scheduler, there exists 635 * cases that the tracing might happen before the need_resched 636 * flag is checked. If this happens and the tracer calls 637 * preempt_enable (after a disable), a schedule might take place 638 * causing an infinite recursion. 639 * 640 * To prevent this, we read the need_resched flag before 641 * disabling preemption. When we want to enable preemption we 642 * check the flag, if it is set, then we call preempt_enable_no_resched. 643 * Otherwise, we call preempt_enable. 644 * 645 * The rational for doing the above is that if need_resched is set 646 * and we have yet to reschedule, we are either in an atomic location 647 * (where we do not need to check for scheduling) or we are inside 648 * the scheduler and do not want to resched. 649 */ 650 static inline int ftrace_preempt_disable(void) 651 { 652 int resched; 653 654 resched = need_resched(); 655 preempt_disable_notrace(); 656 657 return resched; 658 } 659 660 /** 661 * ftrace_preempt_enable - enable preemption scheduler safe 662 * @resched: the return value from ftrace_preempt_disable 663 * 664 * This is a scheduler safe way to enable preemption and not miss 665 * any preemption checks. The disabled saved the state of preemption. 666 * If resched is set, then we are either inside an atomic or 667 * are inside the scheduler (we would have already scheduled 668 * otherwise). In this case, we do not want to call normal 669 * preempt_enable, but preempt_enable_no_resched instead. 670 */ 671 static inline void ftrace_preempt_enable(int resched) 672 { 673 if (resched) 674 preempt_enable_no_resched_notrace(); 675 else 676 preempt_enable_notrace(); 677 } 678 679 #ifdef CONFIG_BRANCH_TRACER 680 extern int enable_branch_tracing(struct trace_array *tr); 681 extern void disable_branch_tracing(void); 682 static inline int trace_branch_enable(struct trace_array *tr) 683 { 684 if (trace_flags & TRACE_ITER_BRANCH) 685 return enable_branch_tracing(tr); 686 return 0; 687 } 688 static inline void trace_branch_disable(void) 689 { 690 /* due to races, always disable */ 691 disable_branch_tracing(); 692 } 693 #else 694 static inline int trace_branch_enable(struct trace_array *tr) 695 { 696 return 0; 697 } 698 static inline void trace_branch_disable(void) 699 { 700 } 701 #endif /* CONFIG_BRANCH_TRACER */ 702 703 /* set ring buffers to default size if not already done so */ 704 int tracing_update_buffers(void); 705 706 /* trace event type bit fields, not numeric */ 707 enum { 708 TRACE_EVENT_TYPE_PRINTF = 1, 709 TRACE_EVENT_TYPE_RAW = 2, 710 }; 711 712 struct ftrace_event_field { 713 struct list_head link; 714 char *name; 715 char *type; 716 int filter_type; 717 int offset; 718 int size; 719 int is_signed; 720 }; 721 722 struct event_filter { 723 int n_preds; 724 struct filter_pred **preds; 725 char *filter_string; 726 }; 727 728 struct event_subsystem { 729 struct list_head list; 730 const char *name; 731 struct dentry *entry; 732 struct event_filter *filter; 733 int nr_events; 734 }; 735 736 struct filter_pred; 737 struct regex; 738 739 typedef int (*filter_pred_fn_t) (struct filter_pred *pred, void *event, 740 int val1, int val2); 741 742 typedef int (*regex_match_func)(char *str, struct regex *r, int len); 743 744 enum regex_type { 745 MATCH_FULL = 0, 746 MATCH_FRONT_ONLY, 747 MATCH_MIDDLE_ONLY, 748 MATCH_END_ONLY, 749 }; 750 751 struct regex { 752 char pattern[MAX_FILTER_STR_VAL]; 753 int len; 754 int field_len; 755 regex_match_func match; 756 }; 757 758 struct filter_pred { 759 filter_pred_fn_t fn; 760 u64 val; 761 struct regex regex; 762 char *field_name; 763 int offset; 764 int not; 765 int op; 766 int pop_n; 767 }; 768 769 extern enum regex_type 770 filter_parse_regex(char *buff, int len, char **search, int *not); 771 extern void print_event_filter(struct ftrace_event_call *call, 772 struct trace_seq *s); 773 extern int apply_event_filter(struct ftrace_event_call *call, 774 char *filter_string); 775 extern int apply_subsystem_event_filter(struct event_subsystem *system, 776 char *filter_string); 777 extern void print_subsystem_event_filter(struct event_subsystem *system, 778 struct trace_seq *s); 779 extern int filter_assign_type(const char *type); 780 781 static inline int 782 filter_check_discard(struct ftrace_event_call *call, void *rec, 783 struct ring_buffer *buffer, 784 struct ring_buffer_event *event) 785 { 786 if (unlikely(call->filter_active) && 787 !filter_match_preds(call->filter, rec)) { 788 ring_buffer_discard_commit(buffer, event); 789 return 1; 790 } 791 792 return 0; 793 } 794 795 extern struct mutex event_mutex; 796 extern struct list_head ftrace_events; 797 798 extern const char *__start___trace_bprintk_fmt[]; 799 extern const char *__stop___trace_bprintk_fmt[]; 800 801 #undef FTRACE_ENTRY 802 #define FTRACE_ENTRY(call, struct_name, id, tstruct, print) \ 803 extern struct ftrace_event_call \ 804 __attribute__((__aligned__(4))) event_##call; 805 #undef FTRACE_ENTRY_DUP 806 #define FTRACE_ENTRY_DUP(call, struct_name, id, tstruct, print) \ 807 FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print)) 808 #include "trace_entries.h" 809 810 #endif /* _LINUX_KERNEL_TRACE_H */ 811