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/ptrace.h>
  14 #include <linux/ktime.h>
  15 #include <linux/sched.h>
  16 #include <linux/types.h>
  17 #include <linux/init.h>
  18 #include <linux/fs.h>
  19
  20 #include <asm/ftrace.h>
  21
  22 /*
  23  * If the arch supports passing the variable contents of
  24  * function_trace_op as the third parameter back from the
  25  * mcount call, then the arch should define this as 1.
  26  */
  27 #ifndef ARCH_SUPPORTS_FTRACE_OPS
  28 #define ARCH_SUPPORTS_FTRACE_OPS 0
  29 #endif
  30
  31 /*
  32  * If the arch's mcount caller does not support all of ftrace's
  33  * features, then it must call an indirect function that
  34  * does. Or at least does enough to prevent any unwelcomed side effects.
  35  */
  36 #if !defined(CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST) || \
  37         !ARCH_SUPPORTS_FTRACE_OPS
  38 # define FTRACE_FORCE_LIST_FUNC 1
  39 #else
  40 # define FTRACE_FORCE_LIST_FUNC 0
  41 #endif
  42
  43
  44 struct module;
  45 struct ftrace_hash;
  46
  47 #ifdef CONFIG_FUNCTION_TRACER
  48
  49 extern int ftrace_enabled;
  50 extern int
  51 ftrace_enable_sysctl(struct ctl_table *table, int write,
  52                      void __user *buffer, size_t *lenp,
  53                      loff_t *ppos);
  54
  55 struct ftrace_ops;
  56
  57 typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
  58                               struct ftrace_ops *op, struct pt_regs *regs);
  59
  60 /*
  61  * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are
  62  * set in the flags member.
  63  *
  64  * ENABLED - set/unset when ftrace_ops is registered/unregistered
  65  * GLOBAL  - set manualy by ftrace_ops user to denote the ftrace_ops
  66  *           is part of the global tracers sharing the same filter
  67  *           via set_ftrace_* debugfs files.
  68  * DYNAMIC - set when ftrace_ops is registered to denote dynamically
  69  *           allocated ftrace_ops which need special care
  70  * CONTROL - set manualy by ftrace_ops user to denote the ftrace_ops
  71  *           could be controled by following calls:
  72  *             ftrace_function_local_enable
  73  *             ftrace_function_local_disable
  74  * SAVE_REGS - The ftrace_ops wants regs saved at each function called
  75  *            and passed to the callback. If this flag is set, but the
  76  *            architecture does not support passing regs
  77  *            (CONFIG_DYNAMIC_FTRACE_WITH_REGS is not defined), then the
  78  *            ftrace_ops will fail to register, unless the next flag
  79  *            is set.
  80  * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the
  81  *            handler can handle an arch that does not save regs
  82  *            (the handler tests if regs == NULL), then it can set
  83  *            this flag instead. It will not fail registering the ftrace_ops
  84  *            but, the regs field will be NULL if the arch does not support
  85  *            passing regs to the handler.
  86  *            Note, if this flag is set, the SAVE_REGS flag will automatically
  87  *            get set upon registering the ftrace_ops, if the arch supports it.
  88  * RECURSION_SAFE - The ftrace_ops can set this to tell the ftrace infrastructure
  89  *            that the call back has its own recursion protection. If it does
  90  *            not set this, then the ftrace infrastructure will add recursion
  91  *            protection for the caller.
  92  * STUB   - The ftrace_ops is just a place holder.
  93  */
  94 enum {
  95         FTRACE_OPS_FL_ENABLED                   = 1 << 0,
  96         FTRACE_OPS_FL_GLOBAL                    = 1 << 1,
  97         FTRACE_OPS_FL_DYNAMIC                   = 1 << 2,
  98         FTRACE_OPS_FL_CONTROL                   = 1 << 3,
  99         FTRACE_OPS_FL_SAVE_REGS                 = 1 << 4,
 100         FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED    = 1 << 5,
 101         FTRACE_OPS_FL_RECURSION_SAFE            = 1 << 6,
 102         FTRACE_OPS_FL_STUB                      = 1 << 7,
 103 };
 104
 105 struct ftrace_ops {
 106         ftrace_func_t                   func;
 107         struct ftrace_ops               *next;
 108         unsigned long                   flags;
 109         int __percpu                    *disabled;
 110 #ifdef CONFIG_DYNAMIC_FTRACE
 111         struct ftrace_hash              *notrace_hash;
 112         struct ftrace_hash              *filter_hash;
 113 #endif
 114 };
 115
 116 extern int function_trace_stop;
 117
 118 /*
 119  * Type of the current tracing.
 120  */
 121 enum ftrace_tracing_type_t {
 122         FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
 123         FTRACE_TYPE_RETURN,     /* Hook the return of the function */
 124 };
 125
 126 /* Current tracing type, default is FTRACE_TYPE_ENTER */
 127 extern enum ftrace_tracing_type_t ftrace_tracing_type;
 128
 129 /**
 130  * ftrace_stop - stop function tracer.
 131  *
 132  * A quick way to stop the function tracer. Note this an on off switch,
 133  * it is not something that is recursive like preempt_disable.
 134  * This does not disable the calling of mcount, it only stops the
 135  * calling of functions from mcount.
 136  */
 137 static inline void ftrace_stop(void)
 138 {
 139         function_trace_stop = 1;
 140 }
 141
 142 /**
 143  * ftrace_start - start the function tracer.
 144  *
 145  * This function is the inverse of ftrace_stop. This does not enable
 146  * the function tracing if the function tracer is disabled. This only
 147  * sets the function tracer flag to continue calling the functions
 148  * from mcount.
 149  */
 150 static inline void ftrace_start(void)
 151 {
 152         function_trace_stop = 0;
 153 }
 154
 155 /*
 156  * The ftrace_ops must be a static and should also
 157  * be read_mostly.  These functions do modify read_mostly variables
 158  * so use them sparely. Never free an ftrace_op or modify the
 159  * next pointer after it has been registered. Even after unregistering
 160  * it, the next pointer may still be used internally.
 161  */
 162 int register_ftrace_function(struct ftrace_ops *ops);
 163 int unregister_ftrace_function(struct ftrace_ops *ops);
 164 void clear_ftrace_function(void);
 165
 166 /**
 167  * ftrace_function_local_enable - enable controlled ftrace_ops on current cpu
 168  *
 169  * This function enables tracing on current cpu by decreasing
 170  * the per cpu control variable.
 171  * It must be called with preemption disabled and only on ftrace_ops
 172  * registered with FTRACE_OPS_FL_CONTROL. If called without preemption
 173  * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
 174  */
 175 static inline void ftrace_function_local_enable(struct ftrace_ops *ops)
 176 {
 177         if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_CONTROL)))
 178                 return;
 179
 180         (*this_cpu_ptr(ops->disabled))--;
 181 }
 182
 183 /**
 184  * ftrace_function_local_disable - enable controlled ftrace_ops on current cpu
 185  *
 186  * This function enables tracing on current cpu by decreasing
 187  * the per cpu control variable.
 188  * It must be called with preemption disabled and only on ftrace_ops
 189  * registered with FTRACE_OPS_FL_CONTROL. If called without preemption
 190  * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
 191  */
 192 static inline void ftrace_function_local_disable(struct ftrace_ops *ops)
 193 {
 194         if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_CONTROL)))
 195                 return;
 196
 197         (*this_cpu_ptr(ops->disabled))++;
 198 }
 199
 200 /**
 201  * ftrace_function_local_disabled - returns ftrace_ops disabled value
 202  *                                  on current cpu
 203  *
 204  * This function returns value of ftrace_ops::disabled on current cpu.
 205  * It must be called with preemption disabled and only on ftrace_ops
 206  * registered with FTRACE_OPS_FL_CONTROL. If called without preemption
 207  * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
 208  */
 209 static inline int ftrace_function_local_disabled(struct ftrace_ops *ops)
 210 {
 211         WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_CONTROL));
 212         return *this_cpu_ptr(ops->disabled);
 213 }
 214
 215 extern void ftrace_stub(unsigned long a0, unsigned long a1,
 216                         struct ftrace_ops *op, struct pt_regs *regs);
 217
 218 #else /* !CONFIG_FUNCTION_TRACER */
 219 /*
 220  * (un)register_ftrace_function must be a macro since the ops parameter
 221  * must not be evaluated.
 222  */
 223 #define register_ftrace_function(ops) ({ 0; })
 224 #define unregister_ftrace_function(ops) ({ 0; })
 225 static inline int ftrace_nr_registered_ops(void)
 226 {
 227         return 0;
 228 }
 229 static inline void clear_ftrace_function(void) { }
 230 static inline void ftrace_kill(void) { }
 231 static inline void ftrace_stop(void) { }
 232 static inline void ftrace_start(void) { }
 233 #endif /* CONFIG_FUNCTION_TRACER */
 234
 235 #ifdef CONFIG_STACK_TRACER
 236 extern int stack_tracer_enabled;
 237 int
 238 stack_trace_sysctl(struct ctl_table *table, int write,
 239                    void __user *buffer, size_t *lenp,
 240                    loff_t *ppos);
 241 #endif
 242
 243 struct ftrace_func_command {
 244         struct list_head        list;
 245         char                    *name;
 246         int                     (*func)(struct ftrace_hash *hash,
 247                                         char *func, char *cmd,
 248                                         char *params, int enable);
 249 };
 250
 251 #ifdef CONFIG_DYNAMIC_FTRACE
 252
 253 int ftrace_arch_code_modify_prepare(void);
 254 int ftrace_arch_code_modify_post_process(void);
 255
 256 void ftrace_bug(int err, unsigned long ip);
 257
 258 struct seq_file;
 259
 260 struct ftrace_probe_ops {
 261         void                    (*func)(unsigned long ip,
 262                                         unsigned long parent_ip,
 263                                         void **data);
 264         int                     (*callback)(unsigned long ip, void **data);
 265         void                    (*free)(void **data);
 266         int                     (*print)(struct seq_file *m,
 267                                          unsigned long ip,
 268                                          struct ftrace_probe_ops *ops,
 269                                          void *data);
 270 };
 271
 272 extern int
 273 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 274                               void *data);
 275 extern void
 276 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 277                                 void *data);
 278 extern void
 279 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops);
 280 extern void unregister_ftrace_function_probe_all(char *glob);
 281
 282 extern int ftrace_text_reserved(void *start, void *end);
 283
 284 extern int ftrace_nr_registered_ops(void);
 285
 286 /*
 287  * The dyn_ftrace record's flags field is split into two parts.
 288  * the first part which is '0-FTRACE_REF_MAX' is a counter of
 289  * the number of callbacks that have registered the function that
 290  * the dyn_ftrace descriptor represents.
 291  *
 292  * The second part is a mask:
 293  *  ENABLED - the function is being traced
 294  *  REGS    - the record wants the function to save regs
 295  *  REGS_EN - the function is set up to save regs.
 296  *
 297  * When a new ftrace_ops is registered and wants a function to save
 298  * pt_regs, the rec->flag REGS is set. When the function has been
 299  * set up to save regs, the REG_EN flag is set. Once a function
 300  * starts saving regs it will do so until all ftrace_ops are removed
 301  * from tracing that function.
 302  */
 303 enum {
 304         FTRACE_FL_ENABLED       = (1UL << 29),
 305         FTRACE_FL_REGS          = (1UL << 30),
 306         FTRACE_FL_REGS_EN       = (1UL << 31)
 307 };
 308
 309 #define FTRACE_FL_MASK          (0x7UL << 29)
 310 #define FTRACE_REF_MAX          ((1UL << 29) - 1)
 311
 312 struct dyn_ftrace {
 313         union {
 314                 unsigned long           ip; /* address of mcount call-site */
 315                 struct dyn_ftrace       *freelist;
 316         };
 317         unsigned long           flags;
 318         struct dyn_arch_ftrace          arch;
 319 };
 320
 321 int ftrace_force_update(void);
 322 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
 323                          int remove, int reset);
 324 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
 325                        int len, int reset);
 326 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
 327                         int len, int reset);
 328 void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
 329 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
 330 void ftrace_free_filter(struct ftrace_ops *ops);
 331
 332 int register_ftrace_command(struct ftrace_func_command *cmd);
 333 int unregister_ftrace_command(struct ftrace_func_command *cmd);
 334
 335 enum {
 336         FTRACE_UPDATE_CALLS             = (1 << 0),
 337         FTRACE_DISABLE_CALLS            = (1 << 1),
 338         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
 339         FTRACE_START_FUNC_RET           = (1 << 3),
 340         FTRACE_STOP_FUNC_RET            = (1 << 4),
 341 };
 342
 343 /*
 344  * The FTRACE_UPDATE_* enum is used to pass information back
 345  * from the ftrace_update_record() and ftrace_test_record()
 346  * functions. These are called by the code update routines
 347  * to find out what is to be done for a given function.
 348  *
 349  *  IGNORE           - The function is already what we want it to be
 350  *  MAKE_CALL        - Start tracing the function
 351  *  MODIFY_CALL      - Stop saving regs for the function
 352  *  MODIFY_CALL_REGS - Start saving regs for the function
 353  *  MAKE_NOP         - Stop tracing the function
 354  */
 355 enum {
 356         FTRACE_UPDATE_IGNORE,
 357         FTRACE_UPDATE_MAKE_CALL,
 358         FTRACE_UPDATE_MODIFY_CALL,
 359         FTRACE_UPDATE_MODIFY_CALL_REGS,
 360         FTRACE_UPDATE_MAKE_NOP,
 361 };
 362
 363 enum {
 364         FTRACE_ITER_FILTER      = (1 << 0),
 365         FTRACE_ITER_NOTRACE     = (1 << 1),
 366         FTRACE_ITER_PRINTALL    = (1 << 2),
 367         FTRACE_ITER_DO_HASH     = (1 << 3),
 368         FTRACE_ITER_HASH        = (1 << 4),
 369         FTRACE_ITER_ENABLED     = (1 << 5),
 370 };
 371
 372 void arch_ftrace_update_code(int command);
 373
 374 struct ftrace_rec_iter;
 375
 376 struct ftrace_rec_iter *ftrace_rec_iter_start(void);
 377 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
 378 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);
 379
 380 #define for_ftrace_rec_iter(iter)               \
 381         for (iter = ftrace_rec_iter_start();    \
 382              iter;                              \
 383              iter = ftrace_rec_iter_next(iter))
 384
 385
 386 int ftrace_update_record(struct dyn_ftrace *rec, int enable);
 387 int ftrace_test_record(struct dyn_ftrace *rec, int enable);
 388 void ftrace_run_stop_machine(int command);
 389 unsigned long ftrace_location(unsigned long ip);
 390
 391 extern ftrace_func_t ftrace_trace_function;
 392
 393 int ftrace_regex_open(struct ftrace_ops *ops, int flag,
 394                   struct inode *inode, struct file *file);
 395 ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 396                             size_t cnt, loff_t *ppos);
 397 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 398                              size_t cnt, loff_t *ppos);
 399 loff_t ftrace_regex_lseek(struct file *file, loff_t offset, int whence);
 400 int ftrace_regex_release(struct inode *inode, struct file *file);
 401
 402 void __init
 403 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
 404
 405 /* defined in arch */
 406 extern int ftrace_ip_converted(unsigned long ip);
 407 extern int ftrace_dyn_arch_init(void *data);
 408 extern void ftrace_replace_code(int enable);
 409 extern int ftrace_update_ftrace_func(ftrace_func_t func);
 410 extern void ftrace_caller(void);
 411 extern void ftrace_regs_caller(void);
 412 extern void ftrace_call(void);
 413 extern void ftrace_regs_call(void);
 414 extern void mcount_call(void);
 415
 416 void ftrace_modify_all_code(int command);
 417
 418 #ifndef FTRACE_ADDR
 419 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
 420 #endif
 421
 422 #ifndef FTRACE_REGS_ADDR
 423 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 424 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller)
 425 #else
 426 # define FTRACE_REGS_ADDR FTRACE_ADDR
 427 #endif
 428 #endif
 429
 430 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 431 extern void ftrace_graph_caller(void);
 432 extern int ftrace_enable_ftrace_graph_caller(void);
 433 extern int ftrace_disable_ftrace_graph_caller(void);
 434 #else
 435 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
 436 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
 437 #endif
 438
 439 /**
 440  * ftrace_make_nop - convert code into nop
 441  * @mod: module structure if called by module load initialization
 442  * @rec: the mcount call site record
 443  * @addr: the address that the call site should be calling
 444  *
 445  * This is a very sensitive operation and great care needs
 446  * to be taken by the arch.  The operation should carefully
 447  * read the location, check to see if what is read is indeed
 448  * what we expect it to be, and then on success of the compare,
 449  * it should write to the location.
 450  *
 451  * The code segment at @rec->ip should be a caller to @addr
 452  *
 453  * Return must be:
 454  *  0 on success
 455  *  -EFAULT on error reading the location
 456  *  -EINVAL on a failed compare of the contents
 457  *  -EPERM  on error writing to the location
 458  * Any other value will be considered a failure.
 459  */
 460 extern int ftrace_make_nop(struct module *mod,
 461                            struct dyn_ftrace *rec, unsigned long addr);
 462
 463 /**
 464  * ftrace_make_call - convert a nop call site into a call to addr
 465  * @rec: the mcount call site record
 466  * @addr: the address that the call site should call
 467  *
 468  * This is a very sensitive operation and great care needs
 469  * to be taken by the arch.  The operation should carefully
 470  * read the location, check to see if what is read is indeed
 471  * what we expect it to be, and then on success of the compare,
 472  * it should write to the location.
 473  *
 474  * The code segment at @rec->ip should be a nop
 475  *
 476  * Return must be:
 477  *  0 on success
 478  *  -EFAULT on error reading the location
 479  *  -EINVAL on a failed compare of the contents
 480  *  -EPERM  on error writing to the location
 481  * Any other value will be considered a failure.
 482  */
 483 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
 484
 485 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 486 /**
 487  * ftrace_modify_call - convert from one addr to another (no nop)
 488  * @rec: the mcount call site record
 489  * @old_addr: the address expected to be currently called to
 490  * @addr: the address to change to
 491  *
 492  * This is a very sensitive operation and great care needs
 493  * to be taken by the arch.  The operation should carefully
 494  * read the location, check to see if what is read is indeed
 495  * what we expect it to be, and then on success of the compare,
 496  * it should write to the location.
 497  *
 498  * The code segment at @rec->ip should be a caller to @old_addr
 499  *
 500  * Return must be:
 501  *  0 on success
 502  *  -EFAULT on error reading the location
 503  *  -EINVAL on a failed compare of the contents
 504  *  -EPERM  on error writing to the location
 505  * Any other value will be considered a failure.
 506  */
 507 extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 508                               unsigned long addr);
 509 #else
 510 /* Should never be called */
 511 static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 512                                      unsigned long addr)
 513 {
 514         return -EINVAL;
 515 }
 516 #endif
 517
 518 /* May be defined in arch */
 519 extern int ftrace_arch_read_dyn_info(char *buf, int size);
 520
 521 extern int skip_trace(unsigned long ip);
 522
 523 extern void ftrace_disable_daemon(void);
 524 extern void ftrace_enable_daemon(void);
 525 #else /* CONFIG_DYNAMIC_FTRACE */
 526 static inline int skip_trace(unsigned long ip) { return 0; }
 527 static inline int ftrace_force_update(void) { return 0; }
 528 static inline void ftrace_disable_daemon(void) { }
 529 static inline void ftrace_enable_daemon(void) { }
 530 static inline void ftrace_release_mod(struct module *mod) {}
 531 static inline int register_ftrace_command(struct ftrace_func_command *cmd)
 532 {
 533         return -EINVAL;
 534 }
 535 static inline int unregister_ftrace_command(char *cmd_name)
 536 {
 537         return -EINVAL;
 538 }
 539 static inline int ftrace_text_reserved(void *start, void *end)
 540 {
 541         return 0;
 542 }
 543 static inline unsigned long ftrace_location(unsigned long ip)
 544 {
 545         return 0;
 546 }
 547
 548 /*
 549  * Again users of functions that have ftrace_ops may not
 550  * have them defined when ftrace is not enabled, but these
 551  * functions may still be called. Use a macro instead of inline.
 552  */
 553 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
 554 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
 555 #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; })
 556 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
 557 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
 558 #define ftrace_free_filter(ops) do { } while (0)
 559
 560 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 561                             size_t cnt, loff_t *ppos) { return -ENODEV; }
 562 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 563                              size_t cnt, loff_t *ppos) { return -ENODEV; }
 564 static inline loff_t ftrace_regex_lseek(struct file *file, loff_t offset, int whence)
 565 {
 566         return -ENODEV;
 567 }
 568 static inline int
 569 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
 570 #endif /* CONFIG_DYNAMIC_FTRACE */
 571
 572 /* totally disable ftrace - can not re-enable after this */
 573 void ftrace_kill(void);
 574
 575 static inline void tracer_disable(void)
 576 {
 577 #ifdef CONFIG_FUNCTION_TRACER
 578         ftrace_enabled = 0;
 579 #endif
 580 }
 581
 582 /*
 583  * Ftrace disable/restore without lock. Some synchronization mechanism
 584  * must be used to prevent ftrace_enabled to be changed between
 585  * disable/restore.
 586  */
 587 static inline int __ftrace_enabled_save(void)
 588 {
 589 #ifdef CONFIG_FUNCTION_TRACER
 590         int saved_ftrace_enabled = ftrace_enabled;
 591         ftrace_enabled = 0;
 592         return saved_ftrace_enabled;
 593 #else
 594         return 0;
 595 #endif
 596 }
 597
 598 static inline void __ftrace_enabled_restore(int enabled)
 599 {
 600 #ifdef CONFIG_FUNCTION_TRACER
 601         ftrace_enabled = enabled;
 602 #endif
 603 }
 604
 605 #ifndef HAVE_ARCH_CALLER_ADDR
 606 # ifdef CONFIG_FRAME_POINTER
 607 #  define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
 608 #  define CALLER_ADDR1 ((unsigned long)__builtin_return_address(1))
 609 #  define CALLER_ADDR2 ((unsigned long)__builtin_return_address(2))
 610 #  define CALLER_ADDR3 ((unsigned long)__builtin_return_address(3))
 611 #  define CALLER_ADDR4 ((unsigned long)__builtin_return_address(4))
 612 #  define CALLER_ADDR5 ((unsigned long)__builtin_return_address(5))
 613 #  define CALLER_ADDR6 ((unsigned long)__builtin_return_address(6))
 614 # else
 615 #  define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
 616 #  define CALLER_ADDR1 0UL
 617 #  define CALLER_ADDR2 0UL
 618 #  define CALLER_ADDR3 0UL
 619 #  define CALLER_ADDR4 0UL
 620 #  define CALLER_ADDR5 0UL
 621 #  define CALLER_ADDR6 0UL
 622 # endif
 623 #endif /* ifndef HAVE_ARCH_CALLER_ADDR */
 624
 625 #ifdef CONFIG_IRQSOFF_TRACER
 626   extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
 627   extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
 628 #else
 629   static inline void time_hardirqs_on(unsigned long a0, unsigned long a1) { }
 630   static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { }
 631 #endif
 632
 633 #ifdef CONFIG_PREEMPT_TRACER
 634   extern void trace_preempt_on(unsigned long a0, unsigned long a1);
 635   extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 636 #else
 637 /*
 638  * Use defines instead of static inlines because some arches will make code out
 639  * of the CALLER_ADDR, when we really want these to be a real nop.
 640  */
 641 # define trace_preempt_on(a0, a1) do { } while (0)
 642 # define trace_preempt_off(a0, a1) do { } while (0)
 643 #endif
 644
 645 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 646 extern void ftrace_init(void);
 647 #else
 648 static inline void ftrace_init(void) { }
 649 #endif
 650
 651 /*
 652  * Structure that defines an entry function trace.
 653  */
 654 struct ftrace_graph_ent {
 655         unsigned long func; /* Current function */
 656         int depth;
 657 };
 658
 659 /*
 660  * Structure that defines a return function trace.
 661  */
 662 struct ftrace_graph_ret {
 663         unsigned long func; /* Current function */
 664         unsigned long long calltime;
 665         unsigned long long rettime;
 666         /* Number of functions that overran the depth limit for current task */
 667         unsigned long overrun;
 668         int depth;
 669 };
 670
 671 /* Type of the callback handlers for tracing function graph*/
 672 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
 673 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
 674
 675 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 676
 677 /* for init task */
 678 #define INIT_FTRACE_GRAPH               .ret_stack = NULL,
 679
 680 /*
 681  * Stack of return addresses for functions
 682  * of a thread.
 683  * Used in struct thread_info
 684  */
 685 struct ftrace_ret_stack {
 686         unsigned long ret;
 687         unsigned long func;
 688         unsigned long long calltime;
 689         unsigned long long subtime;
 690         unsigned long fp;
 691 };
 692
 693 /*
 694  * Primary handler of a function return.
 695  * It relays on ftrace_return_to_handler.
 696  * Defined in entry_32/64.S
 697  */
 698 extern void return_to_handler(void);
 699
 700 extern int
 701 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
 702                          unsigned long frame_pointer);
 703
 704 /*
 705  * Sometimes we don't want to trace a function with the function
 706  * graph tracer but we want them to keep traced by the usual function
 707  * tracer if the function graph tracer is not configured.
 708  */
 709 #define __notrace_funcgraph             notrace
 710
 711 /*
 712  * We want to which function is an entrypoint of a hardirq.
 713  * That will help us to put a signal on output.
 714  */
 715 #define __irq_entry              __attribute__((__section__(".irqentry.text")))
 716
 717 /* Limits of hardirq entrypoints */
 718 extern char __irqentry_text_start[];
 719 extern char __irqentry_text_end[];
 720
 721 #define FTRACE_RETFUNC_DEPTH 50
 722 #define FTRACE_RETSTACK_ALLOC_SIZE 32
 723 extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 724                                 trace_func_graph_ent_t entryfunc);
 725
 726 extern void ftrace_graph_stop(void);
 727
 728 /* The current handlers in use */
 729 extern trace_func_graph_ret_t ftrace_graph_return;
 730 extern trace_func_graph_ent_t ftrace_graph_entry;
 731
 732 extern void unregister_ftrace_graph(void);
 733
 734 extern void ftrace_graph_init_task(struct task_struct *t);
 735 extern void ftrace_graph_exit_task(struct task_struct *t);
 736 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
 737
 738 static inline int task_curr_ret_stack(struct task_struct *t)
 739 {
 740         return t->curr_ret_stack;
 741 }
 742
 743 static inline void pause_graph_tracing(void)
 744 {
 745         atomic_inc(&current->tracing_graph_pause);
 746 }
 747
 748 static inline void unpause_graph_tracing(void)
 749 {
 750         atomic_dec(&current->tracing_graph_pause);
 751 }
 752 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */
 753
 754 #define __notrace_funcgraph
 755 #define __irq_entry
 756 #define INIT_FTRACE_GRAPH
 757
 758 static inline void ftrace_graph_init_task(struct task_struct *t) { }
 759 static inline void ftrace_graph_exit_task(struct task_struct *t) { }
 760 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
 761
 762 static inline int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 763                           trace_func_graph_ent_t entryfunc)
 764 {
 765         return -1;
 766 }
 767 static inline void unregister_ftrace_graph(void) { }
 768
 769 static inline int task_curr_ret_stack(struct task_struct *tsk)
 770 {
 771         return -1;
 772 }
 773
 774 static inline void pause_graph_tracing(void) { }
 775 static inline void unpause_graph_tracing(void) { }
 776 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 777
 778 #ifdef CONFIG_TRACING
 779
 780 /* flags for current->trace */
 781 enum {
 782         TSK_TRACE_FL_TRACE_BIT  = 0,
 783         TSK_TRACE_FL_GRAPH_BIT  = 1,
 784 };
 785 enum {
 786         TSK_TRACE_FL_TRACE      = 1 << TSK_TRACE_FL_TRACE_BIT,
 787         TSK_TRACE_FL_GRAPH      = 1 << TSK_TRACE_FL_GRAPH_BIT,
 788 };
 789
 790 static inline void set_tsk_trace_trace(struct task_struct *tsk)
 791 {
 792         set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 793 }
 794
 795 static inline void clear_tsk_trace_trace(struct task_struct *tsk)
 796 {
 797         clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 798 }
 799
 800 static inline int test_tsk_trace_trace(struct task_struct *tsk)
 801 {
 802         return tsk->trace & TSK_TRACE_FL_TRACE;
 803 }
 804
 805 static inline void set_tsk_trace_graph(struct task_struct *tsk)
 806 {
 807         set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 808 }
 809
 810 static inline void clear_tsk_trace_graph(struct task_struct *tsk)
 811 {
 812         clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 813 }
 814
 815 static inline int test_tsk_trace_graph(struct task_struct *tsk)
 816 {
 817         return tsk->trace & TSK_TRACE_FL_GRAPH;
 818 }
 819
 820 enum ftrace_dump_mode;
 821
 822 extern enum ftrace_dump_mode ftrace_dump_on_oops;
 823
 824 #ifdef CONFIG_PREEMPT
 825 #define INIT_TRACE_RECURSION            .trace_recursion = 0,
 826 #endif
 827
 828 #endif /* CONFIG_TRACING */
 829
 830 #ifndef INIT_TRACE_RECURSION
 831 #define INIT_TRACE_RECURSION
 832 #endif
 833
 834 #ifdef CONFIG_FTRACE_SYSCALLS
 835
 836 unsigned long arch_syscall_addr(int nr);
 837
 838 #endif /* CONFIG_FTRACE_SYSCALLS */
 839
 840 #endif /* _LINUX_FTRACE_H */