include/linux/ftrace.h

   1 /*
   2  * Ftrace header.  For implementation details beyond the random comments
   3  * scattered below, see: Documentation/trace/ftrace-design.txt
   4  */
   5
   6 #ifndef _LINUX_FTRACE_H
   7 #define _LINUX_FTRACE_H
   8
   9 #include <linux/trace_clock.h>
  10 #include <linux/kallsyms.h>
  11 #include <linux/linkage.h>
  12 #include <linux/bitops.h>
  13 #include <linux/ktime.h>
  14 #include <linux/sched.h>
  15 #include <linux/types.h>
  16 #include <linux/init.h>
  17 #include <linux/fs.h>
  18
  19 #include <asm/ftrace.h>
  20
  21 struct module;
  22 struct ftrace_hash;
  23
  24 #ifdef CONFIG_FUNCTION_TRACER
  25
  26 extern int ftrace_enabled;
  27 extern int
  28 ftrace_enable_sysctl(struct ctl_table *table, int write,
  29                      void __user *buffer, size_t *lenp,
  30                      loff_t *ppos);
  31
  32 typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip);
  33
  34 enum {
  35         FTRACE_OPS_FL_ENABLED           = 1 << 0,
  36         FTRACE_OPS_FL_GLOBAL            = 1 << 1,
  37         FTRACE_OPS_FL_DYNAMIC           = 1 << 2,
  38 };
  39
  40 struct ftrace_ops {
  41         ftrace_func_t                   func;
  42         struct ftrace_ops               *next;
  43         unsigned long                   flags;
  44 #ifdef CONFIG_DYNAMIC_FTRACE
  45         struct ftrace_hash              *notrace_hash;
  46         struct ftrace_hash              *filter_hash;
  47 #endif
  48 };
  49
  50 extern int function_trace_stop;
  51
  52 /*
  53  * Type of the current tracing.
  54  */
  55 enum ftrace_tracing_type_t {
  56         FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
  57         FTRACE_TYPE_RETURN,     /* Hook the return of the function */
  58 };
  59
  60 /* Current tracing type, default is FTRACE_TYPE_ENTER */
  61 extern enum ftrace_tracing_type_t ftrace_tracing_type;
  62
  63 /**
  64  * ftrace_stop - stop function tracer.
  65  *
  66  * A quick way to stop the function tracer. Note this an on off switch,
  67  * it is not something that is recursive like preempt_disable.
  68  * This does not disable the calling of mcount, it only stops the
  69  * calling of functions from mcount.
  70  */
  71 static inline void ftrace_stop(void)
  72 {
  73         function_trace_stop = 1;
  74 }
  75
  76 /**
  77  * ftrace_start - start the function tracer.
  78  *
  79  * This function is the inverse of ftrace_stop. This does not enable
  80  * the function tracing if the function tracer is disabled. This only
  81  * sets the function tracer flag to continue calling the functions
  82  * from mcount.
  83  */
  84 static inline void ftrace_start(void)
  85 {
  86         function_trace_stop = 0;
  87 }
  88
  89 /*
  90  * The ftrace_ops must be a static and should also
  91  * be read_mostly.  These functions do modify read_mostly variables
  92  * so use them sparely. Never free an ftrace_op or modify the
  93  * next pointer after it has been registered. Even after unregistering
  94  * it, the next pointer may still be used internally.
  95  */
  96 int register_ftrace_function(struct ftrace_ops *ops);
  97 int unregister_ftrace_function(struct ftrace_ops *ops);
  98 void clear_ftrace_function(void);
  99
 100 extern void ftrace_stub(unsigned long a0, unsigned long a1);
 101
 102 #else /* !CONFIG_FUNCTION_TRACER */
 103 /*
 104  * (un)register_ftrace_function must be a macro since the ops parameter
 105  * must not be evaluated.
 106  */
 107 #define register_ftrace_function(ops) ({ 0; })
 108 #define unregister_ftrace_function(ops) ({ 0; })
 109 static inline void clear_ftrace_function(void) { }
 110 static inline void ftrace_kill(void) { }
 111 static inline void ftrace_stop(void) { }
 112 static inline void ftrace_start(void) { }
 113 #endif /* CONFIG_FUNCTION_TRACER */
 114
 115 #ifdef CONFIG_STACK_TRACER
 116 extern int stack_tracer_enabled;
 117 int
 118 stack_trace_sysctl(struct ctl_table *table, int write,
 119                    void __user *buffer, size_t *lenp,
 120                    loff_t *ppos);
 121 #endif
 122
 123 struct ftrace_func_command {
 124         struct list_head        list;
 125         char                    *name;
 126         int                     (*func)(struct ftrace_hash *hash,
 127                                         char *func, char *cmd,
 128                                         char *params, int enable);
 129 };
 130
 131 #ifdef CONFIG_DYNAMIC_FTRACE
 132
 133 int ftrace_arch_code_modify_prepare(void);
 134 int ftrace_arch_code_modify_post_process(void);
 135
 136 void ftrace_bug(int err, unsigned long ip);
 137
 138 struct seq_file;
 139
 140 struct ftrace_probe_ops {
 141         void                    (*func)(unsigned long ip,
 142                                         unsigned long parent_ip,
 143                                         void **data);
 144         int                     (*callback)(unsigned long ip, void **data);
 145         void                    (*free)(void **data);
 146         int                     (*print)(struct seq_file *m,
 147                                          unsigned long ip,
 148                                          struct ftrace_probe_ops *ops,
 149                                          void *data);
 150 };
 151
 152 extern int
 153 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 154                               void *data);
 155 extern void
 156 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 157                                 void *data);
 158 extern void
 159 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops);
 160 extern void unregister_ftrace_function_probe_all(char *glob);
 161
 162 extern int ftrace_text_reserved(void *start, void *end);
 163
 164 enum {
 165         FTRACE_FL_ENABLED       = (1 << 30),
 166 };
 167
 168 #define FTRACE_FL_MASK          (0x3UL << 30)
 169 #define FTRACE_REF_MAX          ((1 << 30) - 1)
 170
 171 struct dyn_ftrace {
 172         union {
 173                 unsigned long           ip; /* address of mcount call-site */
 174                 struct dyn_ftrace       *freelist;
 175         };
 176         unsigned long           flags;
 177         struct dyn_arch_ftrace          arch;
 178 };
 179
 180 int ftrace_force_update(void);
 181 void ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
 182                        int len, int reset);
 183 void ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
 184                         int len, int reset);
 185 void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
 186 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
 187
 188 int register_ftrace_command(struct ftrace_func_command *cmd);
 189 int unregister_ftrace_command(struct ftrace_func_command *cmd);
 190
 191 enum {
 192         FTRACE_UPDATE_CALLS             = (1 << 0),
 193         FTRACE_DISABLE_CALLS            = (1 << 1),
 194         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
 195         FTRACE_START_FUNC_RET           = (1 << 3),
 196         FTRACE_STOP_FUNC_RET            = (1 << 4),
 197 };
 198
 199 enum {
 200         FTRACE_UPDATE_IGNORE,
 201         FTRACE_UPDATE_MAKE_CALL,
 202         FTRACE_UPDATE_MAKE_NOP,
 203 };
 204
 205 enum {
 206         FTRACE_ITER_FILTER      = (1 << 0),
 207         FTRACE_ITER_NOTRACE     = (1 << 1),
 208         FTRACE_ITER_PRINTALL    = (1 << 2),
 209         FTRACE_ITER_DO_HASH     = (1 << 3),
 210         FTRACE_ITER_HASH        = (1 << 4),
 211         FTRACE_ITER_ENABLED     = (1 << 5),
 212 };
 213
 214 void arch_ftrace_update_code(int command);
 215
 216 struct ftrace_rec_iter;
 217
 218 struct ftrace_rec_iter *ftrace_rec_iter_start(void);
 219 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
 220 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);
 221
 222 int ftrace_update_record(struct dyn_ftrace *rec, int enable);
 223 int ftrace_test_record(struct dyn_ftrace *rec, int enable);
 224 void ftrace_run_stop_machine(int command);
 225 int ftrace_location(unsigned long ip);
 226
 227 extern ftrace_func_t ftrace_trace_function;
 228
 229 int ftrace_regex_open(struct ftrace_ops *ops, int flag,
 230                   struct inode *inode, struct file *file);
 231 ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 232                             size_t cnt, loff_t *ppos);
 233 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 234                              size_t cnt, loff_t *ppos);
 235 loff_t ftrace_regex_lseek(struct file *file, loff_t offset, int origin);
 236 int ftrace_regex_release(struct inode *inode, struct file *file);
 237
 238 void __init
 239 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
 240
 241 /* defined in arch */
 242 extern int ftrace_ip_converted(unsigned long ip);
 243 extern int ftrace_dyn_arch_init(void *data);
 244 extern int ftrace_update_ftrace_func(ftrace_func_t func);
 245 extern void ftrace_caller(void);
 246 extern void ftrace_call(void);
 247 extern void mcount_call(void);
 248
 249 #ifndef FTRACE_ADDR
 250 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
 251 #endif
 252 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 253 extern void ftrace_graph_caller(void);
 254 extern int ftrace_enable_ftrace_graph_caller(void);
 255 extern int ftrace_disable_ftrace_graph_caller(void);
 256 #else
 257 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
 258 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
 259 #endif
 260
 261 /**
 262  * ftrace_make_nop - convert code into nop
 263  * @mod: module structure if called by module load initialization
 264  * @rec: the mcount call site record
 265  * @addr: the address that the call site should be calling
 266  *
 267  * This is a very sensitive operation and great care needs
 268  * to be taken by the arch.  The operation should carefully
 269  * read the location, check to see if what is read is indeed
 270  * what we expect it to be, and then on success of the compare,
 271  * it should write to the location.
 272  *
 273  * The code segment at @rec->ip should be a caller to @addr
 274  *
 275  * Return must be:
 276  *  0 on success
 277  *  -EFAULT on error reading the location
 278  *  -EINVAL on a failed compare of the contents
 279  *  -EPERM  on error writing to the location
 280  * Any other value will be considered a failure.
 281  */
 282 extern int ftrace_make_nop(struct module *mod,
 283                            struct dyn_ftrace *rec, unsigned long addr);
 284
 285 /**
 286  * ftrace_make_call - convert a nop call site into a call to addr
 287  * @rec: the mcount call site record
 288  * @addr: the address that the call site should call
 289  *
 290  * This is a very sensitive operation and great care needs
 291  * to be taken by the arch.  The operation should carefully
 292  * read the location, check to see if what is read is indeed
 293  * what we expect it to be, and then on success of the compare,
 294  * it should write to the location.
 295  *
 296  * The code segment at @rec->ip should be a nop
 297  *
 298  * Return must be:
 299  *  0 on success
 300  *  -EFAULT on error reading the location
 301  *  -EINVAL on a failed compare of the contents
 302  *  -EPERM  on error writing to the location
 303  * Any other value will be considered a failure.
 304  */
 305 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
 306
 307 /* May be defined in arch */
 308 extern int ftrace_arch_read_dyn_info(char *buf, int size);
 309
 310 extern int skip_trace(unsigned long ip);
 311
 312 extern void ftrace_disable_daemon(void);
 313 extern void ftrace_enable_daemon(void);
 314 #else
 315 static inline int skip_trace(unsigned long ip) { return 0; }
 316 static inline int ftrace_force_update(void) { return 0; }
 317 static inline void ftrace_set_filter(unsigned char *buf, int len, int reset)
 318 {
 319 }
 320 static inline void ftrace_disable_daemon(void) { }
 321 static inline void ftrace_enable_daemon(void) { }
 322 static inline void ftrace_release_mod(struct module *mod) {}
 323 static inline int register_ftrace_command(struct ftrace_func_command *cmd)
 324 {
 325         return -EINVAL;
 326 }
 327 static inline int unregister_ftrace_command(char *cmd_name)
 328 {
 329         return -EINVAL;
 330 }
 331 static inline int ftrace_text_reserved(void *start, void *end)
 332 {
 333         return 0;
 334 }
 335
 336 /*
 337  * Again users of functions that have ftrace_ops may not
 338  * have them defined when ftrace is not enabled, but these
 339  * functions may still be called. Use a macro instead of inline.
 340  */
 341 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
 342 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
 343
 344 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 345                             size_t cnt, loff_t *ppos) { return -ENODEV; }
 346 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 347                              size_t cnt, loff_t *ppos) { return -ENODEV; }
 348 static inline loff_t ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
 349 {
 350         return -ENODEV;
 351 }
 352 static inline int
 353 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
 354 #endif /* CONFIG_DYNAMIC_FTRACE */
 355
 356 /* totally disable ftrace - can not re-enable after this */
 357 void ftrace_kill(void);
 358
 359 static inline void tracer_disable(void)
 360 {
 361 #ifdef CONFIG_FUNCTION_TRACER
 362         ftrace_enabled = 0;
 363 #endif
 364 }
 365
 366 /*
 367  * Ftrace disable/restore without lock. Some synchronization mechanism
 368  * must be used to prevent ftrace_enabled to be changed between
 369  * disable/restore.
 370  */
 371 static inline int __ftrace_enabled_save(void)
 372 {
 373 #ifdef CONFIG_FUNCTION_TRACER
 374         int saved_ftrace_enabled = ftrace_enabled;
 375         ftrace_enabled = 0;
 376         return saved_ftrace_enabled;
 377 #else
 378         return 0;
 379 #endif
 380 }
 381
 382 static inline void __ftrace_enabled_restore(int enabled)
 383 {
 384 #ifdef CONFIG_FUNCTION_TRACER
 385         ftrace_enabled = enabled;
 386 #endif
 387 }
 388
 389 #ifndef HAVE_ARCH_CALLER_ADDR
 390 # ifdef CONFIG_FRAME_POINTER
 391 #  define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
 392 #  define CALLER_ADDR1 ((unsigned long)__builtin_return_address(1))
 393 #  define CALLER_ADDR2 ((unsigned long)__builtin_return_address(2))
 394 #  define CALLER_ADDR3 ((unsigned long)__builtin_return_address(3))
 395 #  define CALLER_ADDR4 ((unsigned long)__builtin_return_address(4))
 396 #  define CALLER_ADDR5 ((unsigned long)__builtin_return_address(5))
 397 #  define CALLER_ADDR6 ((unsigned long)__builtin_return_address(6))
 398 # else
 399 #  define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
 400 #  define CALLER_ADDR1 0UL
 401 #  define CALLER_ADDR2 0UL
 402 #  define CALLER_ADDR3 0UL
 403 #  define CALLER_ADDR4 0UL
 404 #  define CALLER_ADDR5 0UL
 405 #  define CALLER_ADDR6 0UL
 406 # endif
 407 #endif /* ifndef HAVE_ARCH_CALLER_ADDR */
 408
 409 #ifdef CONFIG_IRQSOFF_TRACER
 410   extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
 411   extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
 412 #else
 413   static inline void time_hardirqs_on(unsigned long a0, unsigned long a1) { }
 414   static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { }
 415 #endif
 416
 417 #ifdef CONFIG_PREEMPT_TRACER
 418   extern void trace_preempt_on(unsigned long a0, unsigned long a1);
 419   extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 420 #else
 421   static inline void trace_preempt_on(unsigned long a0, unsigned long a1) { }
 422   static inline void trace_preempt_off(unsigned long a0, unsigned long a1) { }
 423 #endif
 424
 425 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 426 extern void ftrace_init(void);
 427 #else
 428 static inline void ftrace_init(void) { }
 429 #endif
 430
 431 /*
 432  * Structure that defines an entry function trace.
 433  */
 434 struct ftrace_graph_ent {
 435         unsigned long func; /* Current function */
 436         int depth;
 437 };
 438
 439 /*
 440  * Structure that defines a return function trace.
 441  */
 442 struct ftrace_graph_ret {
 443         unsigned long func; /* Current function */
 444         unsigned long long calltime;
 445         unsigned long long rettime;
 446         /* Number of functions that overran the depth limit for current task */
 447         unsigned long overrun;
 448         int depth;
 449 };
 450
 451 /* Type of the callback handlers for tracing function graph*/
 452 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
 453 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
 454
 455 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 456
 457 /* for init task */
 458 #define INIT_FTRACE_GRAPH               .ret_stack = NULL,
 459
 460 /*
 461  * Stack of return addresses for functions
 462  * of a thread.
 463  * Used in struct thread_info
 464  */
 465 struct ftrace_ret_stack {
 466         unsigned long ret;
 467         unsigned long func;
 468         unsigned long long calltime;
 469         unsigned long long subtime;
 470         unsigned long fp;
 471 };
 472
 473 /*
 474  * Primary handler of a function return.
 475  * It relays on ftrace_return_to_handler.
 476  * Defined in entry_32/64.S
 477  */
 478 extern void return_to_handler(void);
 479
 480 extern int
 481 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
 482                          unsigned long frame_pointer);
 483
 484 /*
 485  * Sometimes we don't want to trace a function with the function
 486  * graph tracer but we want them to keep traced by the usual function
 487  * tracer if the function graph tracer is not configured.
 488  */
 489 #define __notrace_funcgraph             notrace
 490
 491 /*
 492  * We want to which function is an entrypoint of a hardirq.
 493  * That will help us to put a signal on output.
 494  */
 495 #define __irq_entry              __attribute__((__section__(".irqentry.text")))
 496
 497 /* Limits of hardirq entrypoints */
 498 extern char __irqentry_text_start[];
 499 extern char __irqentry_text_end[];
 500
 501 #define FTRACE_RETFUNC_DEPTH 50
 502 #define FTRACE_RETSTACK_ALLOC_SIZE 32
 503 extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 504                                 trace_func_graph_ent_t entryfunc);
 505
 506 extern void ftrace_graph_stop(void);
 507
 508 /* The current handlers in use */
 509 extern trace_func_graph_ret_t ftrace_graph_return;
 510 extern trace_func_graph_ent_t ftrace_graph_entry;
 511
 512 extern void unregister_ftrace_graph(void);
 513
 514 extern void ftrace_graph_init_task(struct task_struct *t);
 515 extern void ftrace_graph_exit_task(struct task_struct *t);
 516 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
 517
 518 static inline int task_curr_ret_stack(struct task_struct *t)
 519 {
 520         return t->curr_ret_stack;
 521 }
 522
 523 static inline void pause_graph_tracing(void)
 524 {
 525         atomic_inc(&current->tracing_graph_pause);
 526 }
 527
 528 static inline void unpause_graph_tracing(void)
 529 {
 530         atomic_dec(&current->tracing_graph_pause);
 531 }
 532 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */
 533
 534 #define __notrace_funcgraph
 535 #define __irq_entry
 536 #define INIT_FTRACE_GRAPH
 537
 538 static inline void ftrace_graph_init_task(struct task_struct *t) { }
 539 static inline void ftrace_graph_exit_task(struct task_struct *t) { }
 540 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
 541
 542 static inline int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 543                           trace_func_graph_ent_t entryfunc)
 544 {
 545         return -1;
 546 }
 547 static inline void unregister_ftrace_graph(void) { }
 548
 549 static inline int task_curr_ret_stack(struct task_struct *tsk)
 550 {
 551         return -1;
 552 }
 553
 554 static inline void pause_graph_tracing(void) { }
 555 static inline void unpause_graph_tracing(void) { }
 556 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 557
 558 #ifdef CONFIG_TRACING
 559
 560 /* flags for current->trace */
 561 enum {
 562         TSK_TRACE_FL_TRACE_BIT  = 0,
 563         TSK_TRACE_FL_GRAPH_BIT  = 1,
 564 };
 565 enum {
 566         TSK_TRACE_FL_TRACE      = 1 << TSK_TRACE_FL_TRACE_BIT,
 567         TSK_TRACE_FL_GRAPH      = 1 << TSK_TRACE_FL_GRAPH_BIT,
 568 };
 569
 570 static inline void set_tsk_trace_trace(struct task_struct *tsk)
 571 {
 572         set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 573 }
 574
 575 static inline void clear_tsk_trace_trace(struct task_struct *tsk)
 576 {
 577         clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 578 }
 579
 580 static inline int test_tsk_trace_trace(struct task_struct *tsk)
 581 {
 582         return tsk->trace & TSK_TRACE_FL_TRACE;
 583 }
 584
 585 static inline void set_tsk_trace_graph(struct task_struct *tsk)
 586 {
 587         set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 588 }
 589
 590 static inline void clear_tsk_trace_graph(struct task_struct *tsk)
 591 {
 592         clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 593 }
 594
 595 static inline int test_tsk_trace_graph(struct task_struct *tsk)
 596 {
 597         return tsk->trace & TSK_TRACE_FL_GRAPH;
 598 }
 599
 600 enum ftrace_dump_mode;
 601
 602 extern enum ftrace_dump_mode ftrace_dump_on_oops;
 603
 604 #ifdef CONFIG_PREEMPT
 605 #define INIT_TRACE_RECURSION            .trace_recursion = 0,
 606 #endif
 607
 608 #endif /* CONFIG_TRACING */
 609
 610 #ifndef INIT_TRACE_RECURSION
 611 #define INIT_TRACE_RECURSION
 612 #endif
 613
 614 #ifdef CONFIG_FTRACE_SYSCALLS
 615
 616 unsigned long arch_syscall_addr(int nr);
 617
 618 #endif /* CONFIG_FTRACE_SYSCALLS */
 619
 620 #endif /* _LINUX_FTRACE_H */