trace.h 21 KB

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  1. #ifndef _LINUX_KERNEL_TRACE_H
  2. #define _LINUX_KERNEL_TRACE_H
  3. #include <linux/fs.h>
  4. #include <asm/atomic.h>
  5. #include <linux/sched.h>
  6. #include <linux/clocksource.h>
  7. #include <linux/ring_buffer.h>
  8. #include <linux/mmiotrace.h>
  9. #include <linux/ftrace.h>
  10. #include <trace/boot.h>
  11. #include <trace/kmemtrace.h>
  12. #include <trace/power.h>
  13. enum trace_type {
  14. __TRACE_FIRST_TYPE = 0,
  15. TRACE_FN,
  16. TRACE_CTX,
  17. TRACE_WAKE,
  18. TRACE_STACK,
  19. TRACE_PRINT,
  20. TRACE_SPECIAL,
  21. TRACE_MMIO_RW,
  22. TRACE_MMIO_MAP,
  23. TRACE_BRANCH,
  24. TRACE_BOOT_CALL,
  25. TRACE_BOOT_RET,
  26. TRACE_GRAPH_RET,
  27. TRACE_GRAPH_ENT,
  28. TRACE_USER_STACK,
  29. TRACE_HW_BRANCHES,
  30. TRACE_KMEM_ALLOC,
  31. TRACE_KMEM_FREE,
  32. TRACE_POWER,
  33. TRACE_BLK,
  34. __TRACE_LAST_TYPE,
  35. };
  36. /*
  37. * The trace entry - the most basic unit of tracing. This is what
  38. * is printed in the end as a single line in the trace output, such as:
  39. *
  40. * bash-15816 [01] 235.197585: idle_cpu <- irq_enter
  41. */
  42. struct trace_entry {
  43. unsigned char type;
  44. unsigned char flags;
  45. unsigned char preempt_count;
  46. int pid;
  47. int tgid;
  48. };
  49. /*
  50. * Function trace entry - function address and parent function addres:
  51. */
  52. struct ftrace_entry {
  53. struct trace_entry ent;
  54. unsigned long ip;
  55. unsigned long parent_ip;
  56. };
  57. /* Function call entry */
  58. struct ftrace_graph_ent_entry {
  59. struct trace_entry ent;
  60. struct ftrace_graph_ent graph_ent;
  61. };
  62. /* Function return entry */
  63. struct ftrace_graph_ret_entry {
  64. struct trace_entry ent;
  65. struct ftrace_graph_ret ret;
  66. };
  67. extern struct tracer boot_tracer;
  68. /*
  69. * Context switch trace entry - which task (and prio) we switched from/to:
  70. */
  71. struct ctx_switch_entry {
  72. struct trace_entry ent;
  73. unsigned int prev_pid;
  74. unsigned char prev_prio;
  75. unsigned char prev_state;
  76. unsigned int next_pid;
  77. unsigned char next_prio;
  78. unsigned char next_state;
  79. unsigned int next_cpu;
  80. };
  81. /*
  82. * Special (free-form) trace entry:
  83. */
  84. struct special_entry {
  85. struct trace_entry ent;
  86. unsigned long arg1;
  87. unsigned long arg2;
  88. unsigned long arg3;
  89. };
  90. /*
  91. * Stack-trace entry:
  92. */
  93. #define FTRACE_STACK_ENTRIES 8
  94. struct stack_entry {
  95. struct trace_entry ent;
  96. unsigned long caller[FTRACE_STACK_ENTRIES];
  97. };
  98. struct userstack_entry {
  99. struct trace_entry ent;
  100. unsigned long caller[FTRACE_STACK_ENTRIES];
  101. };
  102. /*
  103. * ftrace_printk entry:
  104. */
  105. struct print_entry {
  106. struct trace_entry ent;
  107. unsigned long ip;
  108. int depth;
  109. char buf[];
  110. };
  111. #define TRACE_OLD_SIZE 88
  112. struct trace_field_cont {
  113. unsigned char type;
  114. /* Temporary till we get rid of this completely */
  115. char buf[TRACE_OLD_SIZE - 1];
  116. };
  117. struct trace_mmiotrace_rw {
  118. struct trace_entry ent;
  119. struct mmiotrace_rw rw;
  120. };
  121. struct trace_mmiotrace_map {
  122. struct trace_entry ent;
  123. struct mmiotrace_map map;
  124. };
  125. struct trace_boot_call {
  126. struct trace_entry ent;
  127. struct boot_trace_call boot_call;
  128. };
  129. struct trace_boot_ret {
  130. struct trace_entry ent;
  131. struct boot_trace_ret boot_ret;
  132. };
  133. #define TRACE_FUNC_SIZE 30
  134. #define TRACE_FILE_SIZE 20
  135. struct trace_branch {
  136. struct trace_entry ent;
  137. unsigned line;
  138. char func[TRACE_FUNC_SIZE+1];
  139. char file[TRACE_FILE_SIZE+1];
  140. char correct;
  141. };
  142. struct hw_branch_entry {
  143. struct trace_entry ent;
  144. u64 from;
  145. u64 to;
  146. };
  147. struct trace_power {
  148. struct trace_entry ent;
  149. struct power_trace state_data;
  150. };
  151. struct kmemtrace_alloc_entry {
  152. struct trace_entry ent;
  153. enum kmemtrace_type_id type_id;
  154. unsigned long call_site;
  155. const void *ptr;
  156. size_t bytes_req;
  157. size_t bytes_alloc;
  158. gfp_t gfp_flags;
  159. int node;
  160. };
  161. struct kmemtrace_free_entry {
  162. struct trace_entry ent;
  163. enum kmemtrace_type_id type_id;
  164. unsigned long call_site;
  165. const void *ptr;
  166. };
  167. /*
  168. * trace_flag_type is an enumeration that holds different
  169. * states when a trace occurs. These are:
  170. * IRQS_OFF - interrupts were disabled
  171. * IRQS_NOSUPPORT - arch does not support irqs_disabled_flags
  172. * NEED_RESCED - reschedule is requested
  173. * HARDIRQ - inside an interrupt handler
  174. * SOFTIRQ - inside a softirq handler
  175. */
  176. enum trace_flag_type {
  177. TRACE_FLAG_IRQS_OFF = 0x01,
  178. TRACE_FLAG_IRQS_NOSUPPORT = 0x02,
  179. TRACE_FLAG_NEED_RESCHED = 0x04,
  180. TRACE_FLAG_HARDIRQ = 0x08,
  181. TRACE_FLAG_SOFTIRQ = 0x10,
  182. };
  183. #define TRACE_BUF_SIZE 1024
  184. /*
  185. * The CPU trace array - it consists of thousands of trace entries
  186. * plus some other descriptor data: (for example which task started
  187. * the trace, etc.)
  188. */
  189. struct trace_array_cpu {
  190. atomic_t disabled;
  191. void *buffer_page; /* ring buffer spare */
  192. /* these fields get copied into max-trace: */
  193. unsigned long trace_idx;
  194. unsigned long overrun;
  195. unsigned long saved_latency;
  196. unsigned long critical_start;
  197. unsigned long critical_end;
  198. unsigned long critical_sequence;
  199. unsigned long nice;
  200. unsigned long policy;
  201. unsigned long rt_priority;
  202. cycle_t preempt_timestamp;
  203. pid_t pid;
  204. uid_t uid;
  205. char comm[TASK_COMM_LEN];
  206. };
  207. struct trace_iterator;
  208. /*
  209. * The trace array - an array of per-CPU trace arrays. This is the
  210. * highest level data structure that individual tracers deal with.
  211. * They have on/off state as well:
  212. */
  213. struct trace_array {
  214. struct ring_buffer *buffer;
  215. unsigned long entries;
  216. int cpu;
  217. cycle_t time_start;
  218. struct task_struct *waiter;
  219. struct trace_array_cpu *data[NR_CPUS];
  220. };
  221. #define FTRACE_CMP_TYPE(var, type) \
  222. __builtin_types_compatible_p(typeof(var), type *)
  223. #undef IF_ASSIGN
  224. #define IF_ASSIGN(var, entry, etype, id) \
  225. if (FTRACE_CMP_TYPE(var, etype)) { \
  226. var = (typeof(var))(entry); \
  227. WARN_ON(id && (entry)->type != id); \
  228. break; \
  229. }
  230. /* Will cause compile errors if type is not found. */
  231. extern void __ftrace_bad_type(void);
  232. /*
  233. * The trace_assign_type is a verifier that the entry type is
  234. * the same as the type being assigned. To add new types simply
  235. * add a line with the following format:
  236. *
  237. * IF_ASSIGN(var, ent, type, id);
  238. *
  239. * Where "type" is the trace type that includes the trace_entry
  240. * as the "ent" item. And "id" is the trace identifier that is
  241. * used in the trace_type enum.
  242. *
  243. * If the type can have more than one id, then use zero.
  244. */
  245. #define trace_assign_type(var, ent) \
  246. do { \
  247. IF_ASSIGN(var, ent, struct ftrace_entry, TRACE_FN); \
  248. IF_ASSIGN(var, ent, struct ctx_switch_entry, 0); \
  249. IF_ASSIGN(var, ent, struct stack_entry, TRACE_STACK); \
  250. IF_ASSIGN(var, ent, struct userstack_entry, TRACE_USER_STACK);\
  251. IF_ASSIGN(var, ent, struct print_entry, TRACE_PRINT); \
  252. IF_ASSIGN(var, ent, struct special_entry, 0); \
  253. IF_ASSIGN(var, ent, struct trace_mmiotrace_rw, \
  254. TRACE_MMIO_RW); \
  255. IF_ASSIGN(var, ent, struct trace_mmiotrace_map, \
  256. TRACE_MMIO_MAP); \
  257. IF_ASSIGN(var, ent, struct trace_boot_call, TRACE_BOOT_CALL);\
  258. IF_ASSIGN(var, ent, struct trace_boot_ret, TRACE_BOOT_RET);\
  259. IF_ASSIGN(var, ent, struct trace_branch, TRACE_BRANCH); \
  260. IF_ASSIGN(var, ent, struct ftrace_graph_ent_entry, \
  261. TRACE_GRAPH_ENT); \
  262. IF_ASSIGN(var, ent, struct ftrace_graph_ret_entry, \
  263. TRACE_GRAPH_RET); \
  264. IF_ASSIGN(var, ent, struct hw_branch_entry, TRACE_HW_BRANCHES);\
  265. IF_ASSIGN(var, ent, struct trace_power, TRACE_POWER); \
  266. IF_ASSIGN(var, ent, struct kmemtrace_alloc_entry, \
  267. TRACE_KMEM_ALLOC); \
  268. IF_ASSIGN(var, ent, struct kmemtrace_free_entry, \
  269. TRACE_KMEM_FREE); \
  270. __ftrace_bad_type(); \
  271. } while (0)
  272. /* Return values for print_line callback */
  273. enum print_line_t {
  274. TRACE_TYPE_PARTIAL_LINE = 0, /* Retry after flushing the seq */
  275. TRACE_TYPE_HANDLED = 1,
  276. TRACE_TYPE_UNHANDLED = 2, /* Relay to other output functions */
  277. TRACE_TYPE_NO_CONSUME = 3 /* Handled but ask to not consume */
  278. };
  279. /*
  280. * An option specific to a tracer. This is a boolean value.
  281. * The bit is the bit index that sets its value on the
  282. * flags value in struct tracer_flags.
  283. */
  284. struct tracer_opt {
  285. const char *name; /* Will appear on the trace_options file */
  286. u32 bit; /* Mask assigned in val field in tracer_flags */
  287. };
  288. /*
  289. * The set of specific options for a tracer. Your tracer
  290. * have to set the initial value of the flags val.
  291. */
  292. struct tracer_flags {
  293. u32 val;
  294. struct tracer_opt *opts;
  295. };
  296. /* Makes more easy to define a tracer opt */
  297. #define TRACER_OPT(s, b) .name = #s, .bit = b
  298. /**
  299. * struct tracer - a specific tracer and its callbacks to interact with debugfs
  300. * @name: the name chosen to select it on the available_tracers file
  301. * @init: called when one switches to this tracer (echo name > current_tracer)
  302. * @reset: called when one switches to another tracer
  303. * @start: called when tracing is unpaused (echo 1 > tracing_enabled)
  304. * @stop: called when tracing is paused (echo 0 > tracing_enabled)
  305. * @open: called when the trace file is opened
  306. * @pipe_open: called when the trace_pipe file is opened
  307. * @wait_pipe: override how the user waits for traces on trace_pipe
  308. * @close: called when the trace file is released
  309. * @read: override the default read callback on trace_pipe
  310. * @splice_read: override the default splice_read callback on trace_pipe
  311. * @selftest: selftest to run on boot (see trace_selftest.c)
  312. * @print_headers: override the first lines that describe your columns
  313. * @print_line: callback that prints a trace
  314. * @set_flag: signals one of your private flags changed (trace_options file)
  315. * @flags: your private flags
  316. */
  317. struct tracer {
  318. const char *name;
  319. int (*init)(struct trace_array *tr);
  320. void (*reset)(struct trace_array *tr);
  321. void (*start)(struct trace_array *tr);
  322. void (*stop)(struct trace_array *tr);
  323. void (*open)(struct trace_iterator *iter);
  324. void (*pipe_open)(struct trace_iterator *iter);
  325. void (*wait_pipe)(struct trace_iterator *iter);
  326. void (*close)(struct trace_iterator *iter);
  327. ssize_t (*read)(struct trace_iterator *iter,
  328. struct file *filp, char __user *ubuf,
  329. size_t cnt, loff_t *ppos);
  330. ssize_t (*splice_read)(struct trace_iterator *iter,
  331. struct file *filp,
  332. loff_t *ppos,
  333. struct pipe_inode_info *pipe,
  334. size_t len,
  335. unsigned int flags);
  336. #ifdef CONFIG_FTRACE_STARTUP_TEST
  337. int (*selftest)(struct tracer *trace,
  338. struct trace_array *tr);
  339. #endif
  340. void (*print_header)(struct seq_file *m);
  341. enum print_line_t (*print_line)(struct trace_iterator *iter);
  342. /* If you handled the flag setting, return 0 */
  343. int (*set_flag)(u32 old_flags, u32 bit, int set);
  344. struct tracer *next;
  345. int print_max;
  346. struct tracer_flags *flags;
  347. struct tracer_stat *stats;
  348. };
  349. struct trace_seq {
  350. unsigned char buffer[PAGE_SIZE];
  351. unsigned int len;
  352. unsigned int readpos;
  353. };
  354. static inline void
  355. trace_seq_init(struct trace_seq *s)
  356. {
  357. s->len = 0;
  358. s->readpos = 0;
  359. }
  360. #define TRACE_PIPE_ALL_CPU -1
  361. /*
  362. * Trace iterator - used by printout routines who present trace
  363. * results to users and which routines might sleep, etc:
  364. */
  365. struct trace_iterator {
  366. struct trace_array *tr;
  367. struct tracer *trace;
  368. void *private;
  369. int cpu_file;
  370. struct mutex mutex;
  371. struct ring_buffer_iter *buffer_iter[NR_CPUS];
  372. /* The below is zeroed out in pipe_read */
  373. struct trace_seq seq;
  374. struct trace_entry *ent;
  375. int cpu;
  376. u64 ts;
  377. unsigned long iter_flags;
  378. loff_t pos;
  379. long idx;
  380. cpumask_var_t started;
  381. };
  382. int tracer_init(struct tracer *t, struct trace_array *tr);
  383. int tracing_is_enabled(void);
  384. void trace_wake_up(void);
  385. void tracing_reset(struct trace_array *tr, int cpu);
  386. void tracing_reset_online_cpus(struct trace_array *tr);
  387. int tracing_open_generic(struct inode *inode, struct file *filp);
  388. struct dentry *tracing_init_dentry(void);
  389. void init_tracer_sysprof_debugfs(struct dentry *d_tracer);
  390. struct ring_buffer_event;
  391. struct ring_buffer_event *trace_buffer_lock_reserve(struct trace_array *tr,
  392. unsigned char type,
  393. unsigned long len,
  394. unsigned long flags,
  395. int pc);
  396. void trace_buffer_unlock_commit(struct trace_array *tr,
  397. struct ring_buffer_event *event,
  398. unsigned long flags, int pc);
  399. struct ring_buffer_event *
  400. trace_current_buffer_lock_reserve(unsigned char type, unsigned long len,
  401. unsigned long flags, int pc);
  402. void trace_current_buffer_unlock_commit(struct ring_buffer_event *event,
  403. unsigned long flags, int pc);
  404. struct trace_entry *tracing_get_trace_entry(struct trace_array *tr,
  405. struct trace_array_cpu *data);
  406. struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
  407. int *ent_cpu, u64 *ent_ts);
  408. void tracing_generic_entry_update(struct trace_entry *entry,
  409. unsigned long flags,
  410. int pc);
  411. void default_wait_pipe(struct trace_iterator *iter);
  412. void poll_wait_pipe(struct trace_iterator *iter);
  413. void ftrace(struct trace_array *tr,
  414. struct trace_array_cpu *data,
  415. unsigned long ip,
  416. unsigned long parent_ip,
  417. unsigned long flags, int pc);
  418. void tracing_sched_switch_trace(struct trace_array *tr,
  419. struct task_struct *prev,
  420. struct task_struct *next,
  421. unsigned long flags, int pc);
  422. void tracing_record_cmdline(struct task_struct *tsk);
  423. void tracing_sched_wakeup_trace(struct trace_array *tr,
  424. struct task_struct *wakee,
  425. struct task_struct *cur,
  426. unsigned long flags, int pc);
  427. void trace_special(struct trace_array *tr,
  428. struct trace_array_cpu *data,
  429. unsigned long arg1,
  430. unsigned long arg2,
  431. unsigned long arg3, int pc);
  432. void trace_function(struct trace_array *tr,
  433. unsigned long ip,
  434. unsigned long parent_ip,
  435. unsigned long flags, int pc);
  436. void trace_graph_return(struct ftrace_graph_ret *trace);
  437. int trace_graph_entry(struct ftrace_graph_ent *trace);
  438. void tracing_start_cmdline_record(void);
  439. void tracing_stop_cmdline_record(void);
  440. void tracing_sched_switch_assign_trace(struct trace_array *tr);
  441. void tracing_stop_sched_switch_record(void);
  442. void tracing_start_sched_switch_record(void);
  443. int register_tracer(struct tracer *type);
  444. void unregister_tracer(struct tracer *type);
  445. extern unsigned long nsecs_to_usecs(unsigned long nsecs);
  446. extern unsigned long tracing_max_latency;
  447. extern unsigned long tracing_thresh;
  448. void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu);
  449. void update_max_tr_single(struct trace_array *tr,
  450. struct task_struct *tsk, int cpu);
  451. void __trace_stack(struct trace_array *tr,
  452. unsigned long flags,
  453. int skip, int pc);
  454. extern cycle_t ftrace_now(int cpu);
  455. #ifdef CONFIG_CONTEXT_SWITCH_TRACER
  456. typedef void
  457. (*tracer_switch_func_t)(void *private,
  458. void *__rq,
  459. struct task_struct *prev,
  460. struct task_struct *next);
  461. struct tracer_switch_ops {
  462. tracer_switch_func_t func;
  463. void *private;
  464. struct tracer_switch_ops *next;
  465. };
  466. #endif /* CONFIG_CONTEXT_SWITCH_TRACER */
  467. extern char *trace_find_cmdline(int pid);
  468. #ifdef CONFIG_DYNAMIC_FTRACE
  469. extern unsigned long ftrace_update_tot_cnt;
  470. #define DYN_FTRACE_TEST_NAME trace_selftest_dynamic_test_func
  471. extern int DYN_FTRACE_TEST_NAME(void);
  472. #endif
  473. #ifdef CONFIG_FTRACE_STARTUP_TEST
  474. extern int trace_selftest_startup_function(struct tracer *trace,
  475. struct trace_array *tr);
  476. extern int trace_selftest_startup_function_graph(struct tracer *trace,
  477. struct trace_array *tr);
  478. extern int trace_selftest_startup_irqsoff(struct tracer *trace,
  479. struct trace_array *tr);
  480. extern int trace_selftest_startup_preemptoff(struct tracer *trace,
  481. struct trace_array *tr);
  482. extern int trace_selftest_startup_preemptirqsoff(struct tracer *trace,
  483. struct trace_array *tr);
  484. extern int trace_selftest_startup_wakeup(struct tracer *trace,
  485. struct trace_array *tr);
  486. extern int trace_selftest_startup_nop(struct tracer *trace,
  487. struct trace_array *tr);
  488. extern int trace_selftest_startup_sched_switch(struct tracer *trace,
  489. struct trace_array *tr);
  490. extern int trace_selftest_startup_sysprof(struct tracer *trace,
  491. struct trace_array *tr);
  492. extern int trace_selftest_startup_branch(struct tracer *trace,
  493. struct trace_array *tr);
  494. #endif /* CONFIG_FTRACE_STARTUP_TEST */
  495. extern void *head_page(struct trace_array_cpu *data);
  496. extern long ns2usecs(cycle_t nsec);
  497. extern int
  498. trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args);
  499. extern unsigned long trace_flags;
  500. /* Standard output formatting function used for function return traces */
  501. #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  502. extern enum print_line_t print_graph_function(struct trace_iterator *iter);
  503. #ifdef CONFIG_DYNAMIC_FTRACE
  504. /* TODO: make this variable */
  505. #define FTRACE_GRAPH_MAX_FUNCS 32
  506. extern int ftrace_graph_count;
  507. extern unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS];
  508. static inline int ftrace_graph_addr(unsigned long addr)
  509. {
  510. int i;
  511. if (!ftrace_graph_count || test_tsk_trace_graph(current))
  512. return 1;
  513. for (i = 0; i < ftrace_graph_count; i++) {
  514. if (addr == ftrace_graph_funcs[i])
  515. return 1;
  516. }
  517. return 0;
  518. }
  519. #else
  520. static inline int ftrace_trace_addr(unsigned long addr)
  521. {
  522. return 1;
  523. }
  524. static inline int ftrace_graph_addr(unsigned long addr)
  525. {
  526. return 1;
  527. }
  528. #endif /* CONFIG_DYNAMIC_FTRACE */
  529. #else /* CONFIG_FUNCTION_GRAPH_TRACER */
  530. static inline enum print_line_t
  531. print_graph_function(struct trace_iterator *iter)
  532. {
  533. return TRACE_TYPE_UNHANDLED;
  534. }
  535. #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
  536. extern struct pid *ftrace_pid_trace;
  537. static inline int ftrace_trace_task(struct task_struct *task)
  538. {
  539. if (!ftrace_pid_trace)
  540. return 1;
  541. return test_tsk_trace_trace(task);
  542. }
  543. /*
  544. * trace_iterator_flags is an enumeration that defines bit
  545. * positions into trace_flags that controls the output.
  546. *
  547. * NOTE: These bits must match the trace_options array in
  548. * trace.c.
  549. */
  550. enum trace_iterator_flags {
  551. TRACE_ITER_PRINT_PARENT = 0x01,
  552. TRACE_ITER_SYM_OFFSET = 0x02,
  553. TRACE_ITER_SYM_ADDR = 0x04,
  554. TRACE_ITER_VERBOSE = 0x08,
  555. TRACE_ITER_RAW = 0x10,
  556. TRACE_ITER_HEX = 0x20,
  557. TRACE_ITER_BIN = 0x40,
  558. TRACE_ITER_BLOCK = 0x80,
  559. TRACE_ITER_STACKTRACE = 0x100,
  560. TRACE_ITER_SCHED_TREE = 0x200,
  561. TRACE_ITER_PRINTK = 0x400,
  562. TRACE_ITER_PREEMPTONLY = 0x800,
  563. TRACE_ITER_BRANCH = 0x1000,
  564. TRACE_ITER_ANNOTATE = 0x2000,
  565. TRACE_ITER_USERSTACKTRACE = 0x4000,
  566. TRACE_ITER_SYM_USEROBJ = 0x8000,
  567. TRACE_ITER_PRINTK_MSGONLY = 0x10000,
  568. TRACE_ITER_CONTEXT_INFO = 0x20000, /* Print pid/cpu/time */
  569. TRACE_ITER_LATENCY_FMT = 0x40000,
  570. };
  571. /*
  572. * TRACE_ITER_SYM_MASK masks the options in trace_flags that
  573. * control the output of kernel symbols.
  574. */
  575. #define TRACE_ITER_SYM_MASK \
  576. (TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR)
  577. extern struct tracer nop_trace;
  578. /**
  579. * ftrace_preempt_disable - disable preemption scheduler safe
  580. *
  581. * When tracing can happen inside the scheduler, there exists
  582. * cases that the tracing might happen before the need_resched
  583. * flag is checked. If this happens and the tracer calls
  584. * preempt_enable (after a disable), a schedule might take place
  585. * causing an infinite recursion.
  586. *
  587. * To prevent this, we read the need_resched flag before
  588. * disabling preemption. When we want to enable preemption we
  589. * check the flag, if it is set, then we call preempt_enable_no_resched.
  590. * Otherwise, we call preempt_enable.
  591. *
  592. * The rational for doing the above is that if need_resched is set
  593. * and we have yet to reschedule, we are either in an atomic location
  594. * (where we do not need to check for scheduling) or we are inside
  595. * the scheduler and do not want to resched.
  596. */
  597. static inline int ftrace_preempt_disable(void)
  598. {
  599. int resched;
  600. resched = need_resched();
  601. preempt_disable_notrace();
  602. return resched;
  603. }
  604. /**
  605. * ftrace_preempt_enable - enable preemption scheduler safe
  606. * @resched: the return value from ftrace_preempt_disable
  607. *
  608. * This is a scheduler safe way to enable preemption and not miss
  609. * any preemption checks. The disabled saved the state of preemption.
  610. * If resched is set, then we are either inside an atomic or
  611. * are inside the scheduler (we would have already scheduled
  612. * otherwise). In this case, we do not want to call normal
  613. * preempt_enable, but preempt_enable_no_resched instead.
  614. */
  615. static inline void ftrace_preempt_enable(int resched)
  616. {
  617. if (resched)
  618. preempt_enable_no_resched_notrace();
  619. else
  620. preempt_enable_notrace();
  621. }
  622. #ifdef CONFIG_BRANCH_TRACER
  623. extern int enable_branch_tracing(struct trace_array *tr);
  624. extern void disable_branch_tracing(void);
  625. static inline int trace_branch_enable(struct trace_array *tr)
  626. {
  627. if (trace_flags & TRACE_ITER_BRANCH)
  628. return enable_branch_tracing(tr);
  629. return 0;
  630. }
  631. static inline void trace_branch_disable(void)
  632. {
  633. /* due to races, always disable */
  634. disable_branch_tracing();
  635. }
  636. #else
  637. static inline int trace_branch_enable(struct trace_array *tr)
  638. {
  639. return 0;
  640. }
  641. static inline void trace_branch_disable(void)
  642. {
  643. }
  644. #endif /* CONFIG_BRANCH_TRACER */
  645. /* trace event type bit fields, not numeric */
  646. enum {
  647. TRACE_EVENT_TYPE_PRINTF = 1,
  648. TRACE_EVENT_TYPE_RAW = 2,
  649. };
  650. struct ftrace_event_call {
  651. char *name;
  652. char *system;
  653. struct dentry *dir;
  654. int enabled;
  655. int (*regfunc)(void);
  656. void (*unregfunc)(void);
  657. int id;
  658. struct dentry *raw_dir;
  659. int raw_enabled;
  660. int type;
  661. int (*raw_init)(void);
  662. int (*raw_reg)(void);
  663. void (*raw_unreg)(void);
  664. int (*show_format)(struct trace_seq *s);
  665. };
  666. void event_trace_printk(unsigned long ip, const char *fmt, ...);
  667. extern struct ftrace_event_call __start_ftrace_events[];
  668. extern struct ftrace_event_call __stop_ftrace_events[];
  669. #endif /* _LINUX_KERNEL_TRACE_H */