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  * DYNAMIC - set when ftrace_ops is registered to denote dynamically
  66  *           allocated ftrace_ops which need special care
  67  * CONTROL - set manualy by ftrace_ops user to denote the ftrace_ops
  68  *           could be controled by following calls:
  69  *             ftrace_function_local_enable
  70  *             ftrace_function_local_disable
  71  * SAVE_REGS - The ftrace_ops wants regs saved at each function called
  72  *            and passed to the callback. If this flag is set, but the
  73  *            architecture does not support passing regs
  74  *            (CONFIG_DYNAMIC_FTRACE_WITH_REGS is not defined), then the
  75  *            ftrace_ops will fail to register, unless the next flag
  76  *            is set.
  77  * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the
  78  *            handler can handle an arch that does not save regs
  79  *            (the handler tests if regs == NULL), then it can set
  80  *            this flag instead. It will not fail registering the ftrace_ops
  81  *            but, the regs field will be NULL if the arch does not support
  82  *            passing regs to the handler.
  83  *            Note, if this flag is set, the SAVE_REGS flag will automatically
  84  *            get set upon registering the ftrace_ops, if the arch supports it.
  85  * RECURSION_SAFE - The ftrace_ops can set this to tell the ftrace infrastructure
  86  *            that the call back has its own recursion protection. If it does
  87  *            not set this, then the ftrace infrastructure will add recursion
  88  *            protection for the caller.
  89  * STUB   - The ftrace_ops is just a place holder.
  90  * INITIALIZED - The ftrace_ops has already been initialized (first use time
  91  *            register_ftrace_function() is called, it will initialized the ops)
  92  * DELETED - The ops are being deleted, do not let them be registered again.
  93  */
  94 enum {
  95         FTRACE_OPS_FL_ENABLED                   = 1 << 0,
  96         FTRACE_OPS_FL_DYNAMIC                   = 1 << 1,
  97         FTRACE_OPS_FL_CONTROL                   = 1 << 2,
  98         FTRACE_OPS_FL_SAVE_REGS                 = 1 << 3,
  99         FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED    = 1 << 4,
 100         FTRACE_OPS_FL_RECURSION_SAFE            = 1 << 5,
 101         FTRACE_OPS_FL_STUB                      = 1 << 6,
 102         FTRACE_OPS_FL_INITIALIZED               = 1 << 7,
 103         FTRACE_OPS_FL_DELETED                   = 1 << 8,
 104 };
 105
 106 /*
 107  * Note, ftrace_ops can be referenced outside of RCU protection.
 108  * (Although, for perf, the control ops prevent that). If ftrace_ops is
 109  * allocated and not part of kernel core data, the unregistering of it will
 110  * perform a scheduling on all CPUs to make sure that there are no more users.
 111  * Depending on the load of the system that may take a bit of time.
 112  *
 113  * Any private data added must also take care not to be freed and if private
 114  * data is added to a ftrace_ops that is in core code, the user of the
 115  * ftrace_ops must perform a schedule_on_each_cpu() before freeing it.
 116  */
 117 struct ftrace_ops {
 118         ftrace_func_t                   func;
 119         struct ftrace_ops               *next;
 120         unsigned long                   flags;
 121         int __percpu                    *disabled;
 122         void                            *private;
 123 #ifdef CONFIG_DYNAMIC_FTRACE
 124         struct ftrace_hash              *notrace_hash;
 125         struct ftrace_hash              *filter_hash;
 126         struct mutex                    regex_lock;
 127 #endif
 128 };
 129
 130 extern int function_trace_stop;
 131
 132 /*
 133  * Type of the current tracing.
 134  */
 135 enum ftrace_tracing_type_t {
 136         FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
 137         FTRACE_TYPE_RETURN,     /* Hook the return of the function */
 138 };
 139
 140 /* Current tracing type, default is FTRACE_TYPE_ENTER */
 141 extern enum ftrace_tracing_type_t ftrace_tracing_type;
 142
 143 /**
 144  * ftrace_stop - stop function tracer.
 145  *
 146  * A quick way to stop the function tracer. Note this an on off switch,
 147  * it is not something that is recursive like preempt_disable.
 148  * This does not disable the calling of mcount, it only stops the
 149  * calling of functions from mcount.
 150  */
 151 static inline void ftrace_stop(void)
 152 {
 153         function_trace_stop = 1;
 154 }
 155
 156 /**
 157  * ftrace_start - start the function tracer.
 158  *
 159  * This function is the inverse of ftrace_stop. This does not enable
 160  * the function tracing if the function tracer is disabled. This only
 161  * sets the function tracer flag to continue calling the functions
 162  * from mcount.
 163  */
 164 static inline void ftrace_start(void)
 165 {
 166         function_trace_stop = 0;
 167 }
 168
 169 /*
 170  * The ftrace_ops must be a static and should also
 171  * be read_mostly.  These functions do modify read_mostly variables
 172  * so use them sparely. Never free an ftrace_op or modify the
 173  * next pointer after it has been registered. Even after unregistering
 174  * it, the next pointer may still be used internally.
 175  */
 176 int register_ftrace_function(struct ftrace_ops *ops);
 177 int unregister_ftrace_function(struct ftrace_ops *ops);
 178 void clear_ftrace_function(void);
 179
 180 /**
 181  * ftrace_function_local_enable - enable controlled ftrace_ops on current cpu
 182  *
 183  * This function enables tracing on current cpu by decreasing
 184  * the per cpu control variable.
 185  * It must be called with preemption disabled and only on ftrace_ops
 186  * registered with FTRACE_OPS_FL_CONTROL. If called without preemption
 187  * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
 188  */
 189 static inline void ftrace_function_local_enable(struct ftrace_ops *ops)
 190 {
 191         if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_CONTROL)))
 192                 return;
 193
 194         (*this_cpu_ptr(ops->disabled))--;
 195 }
 196
 197 /**
 198  * ftrace_function_local_disable - enable controlled ftrace_ops on current cpu
 199  *
 200  * This function enables tracing on current cpu by decreasing
 201  * the per cpu control variable.
 202  * It must be called with preemption disabled and only on ftrace_ops
 203  * registered with FTRACE_OPS_FL_CONTROL. If called without preemption
 204  * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
 205  */
 206 static inline void ftrace_function_local_disable(struct ftrace_ops *ops)
 207 {
 208         if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_CONTROL)))
 209                 return;
 210
 211         (*this_cpu_ptr(ops->disabled))++;
 212 }
 213
 214 /**
 215  * ftrace_function_local_disabled - returns ftrace_ops disabled value
 216  *                                  on current cpu
 217  *
 218  * This function returns value of ftrace_ops::disabled on current cpu.
 219  * It must be called with preemption disabled and only on ftrace_ops
 220  * registered with FTRACE_OPS_FL_CONTROL. If called without preemption
 221  * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
 222  */
 223 static inline int ftrace_function_local_disabled(struct ftrace_ops *ops)
 224 {
 225         WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_CONTROL));
 226         return *this_cpu_ptr(ops->disabled);
 227 }
 228
 229 extern void ftrace_stub(unsigned long a0, unsigned long a1,
 230                         struct ftrace_ops *op, struct pt_regs *regs);
 231
 232 #else /* !CONFIG_FUNCTION_TRACER */
 233 /*
 234  * (un)register_ftrace_function must be a macro since the ops parameter
 235  * must not be evaluated.
 236  */
 237 #define register_ftrace_function(ops) ({ 0; })
 238 #define unregister_ftrace_function(ops) ({ 0; })
 239 static inline int ftrace_nr_registered_ops(void)
 240 {
 241         return 0;
 242 }
 243 static inline void clear_ftrace_function(void) { }
 244 static inline void ftrace_kill(void) { }
 245 static inline void ftrace_stop(void) { }
 246 static inline void ftrace_start(void) { }
 247 #endif /* CONFIG_FUNCTION_TRACER */
 248
 249 #ifdef CONFIG_STACK_TRACER
 250 extern int stack_tracer_enabled;
 251 int
 252 stack_trace_sysctl(struct ctl_table *table, int write,
 253                    void __user *buffer, size_t *lenp,
 254                    loff_t *ppos);
 255 #endif
 256
 257 struct ftrace_func_command {
 258         struct list_head        list;
 259         char                    *name;
 260         int                     (*func)(struct ftrace_hash *hash,
 261                                         char *func, char *cmd,
 262                                         char *params, int enable);
 263 };
 264
 265 #ifdef CONFIG_DYNAMIC_FTRACE
 266
 267 int ftrace_arch_code_modify_prepare(void);
 268 int ftrace_arch_code_modify_post_process(void);
 269
 270 void ftrace_bug(int err, unsigned long ip);
 271
 272 struct seq_file;
 273
 274 struct ftrace_probe_ops {
 275         void                    (*func)(unsigned long ip,
 276                                         unsigned long parent_ip,
 277                                         void **data);
 278         int                     (*init)(struct ftrace_probe_ops *ops,
 279                                         unsigned long ip, void **data);
 280         void                    (*free)(struct ftrace_probe_ops *ops,
 281                                         unsigned long ip, void **data);
 282         int                     (*print)(struct seq_file *m,
 283                                          unsigned long ip,
 284                                          struct ftrace_probe_ops *ops,
 285                                          void *data);
 286 };
 287
 288 extern int
 289 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 290                               void *data);
 291 extern void
 292 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 293                                 void *data);
 294 extern void
 295 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops);
 296 extern void unregister_ftrace_function_probe_all(char *glob);
 297
 298 extern int ftrace_text_reserved(const void *start, const void *end);
 299
 300 extern int ftrace_nr_registered_ops(void);
 301
 302 /*
 303  * The dyn_ftrace record's flags field is split into two parts.
 304  * the first part which is '0-FTRACE_REF_MAX' is a counter of
 305  * the number of callbacks that have registered the function that
 306  * the dyn_ftrace descriptor represents.
 307  *
 308  * The second part is a mask:
 309  *  ENABLED - the function is being traced
 310  *  REGS    - the record wants the function to save regs
 311  *  REGS_EN - the function is set up to save regs.
 312  *
 313  * When a new ftrace_ops is registered and wants a function to save
 314  * pt_regs, the rec->flag REGS is set. When the function has been
 315  * set up to save regs, the REG_EN flag is set. Once a function
 316  * starts saving regs it will do so until all ftrace_ops are removed
 317  * from tracing that function.
 318  */
 319 enum {
 320         FTRACE_FL_ENABLED       = (1UL << 29),
 321         FTRACE_FL_REGS          = (1UL << 30),
 322         FTRACE_FL_REGS_EN       = (1UL << 31)
 323 };
 324
 325 #define FTRACE_FL_MASK          (0x7UL << 29)
 326 #define FTRACE_REF_MAX          ((1UL << 29) - 1)
 327
 328 struct dyn_ftrace {
 329         unsigned long           ip; /* address of mcount call-site */
 330         unsigned long           flags;
 331         struct dyn_arch_ftrace  arch;
 332 };
 333
 334 int ftrace_force_update(void);
 335 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
 336                          int remove, int reset);
 337 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
 338                        int len, int reset);
 339 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
 340                         int len, int reset);
 341 void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
 342 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
 343 void ftrace_free_filter(struct ftrace_ops *ops);
 344
 345 int register_ftrace_command(struct ftrace_func_command *cmd);
 346 int unregister_ftrace_command(struct ftrace_func_command *cmd);
 347
 348 enum {
 349         FTRACE_UPDATE_CALLS             = (1 << 0),
 350         FTRACE_DISABLE_CALLS            = (1 << 1),
 351         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
 352         FTRACE_START_FUNC_RET           = (1 << 3),
 353         FTRACE_STOP_FUNC_RET            = (1 << 4),
 354 };
 355
 356 /*
 357  * The FTRACE_UPDATE_* enum is used to pass information back
 358  * from the ftrace_update_record() and ftrace_test_record()
 359  * functions. These are called by the code update routines
 360  * to find out what is to be done for a given function.
 361  *
 362  *  IGNORE           - The function is already what we want it to be
 363  *  MAKE_CALL        - Start tracing the function
 364  *  MODIFY_CALL      - Stop saving regs for the function
 365  *  MAKE_NOP         - Stop tracing the function
 366  */
 367 enum {
 368         FTRACE_UPDATE_IGNORE,
 369         FTRACE_UPDATE_MAKE_CALL,
 370         FTRACE_UPDATE_MODIFY_CALL,
 371         FTRACE_UPDATE_MAKE_NOP,
 372 };
 373
 374 enum {
 375         FTRACE_ITER_FILTER      = (1 << 0),
 376         FTRACE_ITER_NOTRACE     = (1 << 1),
 377         FTRACE_ITER_PRINTALL    = (1 << 2),
 378         FTRACE_ITER_DO_HASH     = (1 << 3),
 379         FTRACE_ITER_HASH        = (1 << 4),
 380         FTRACE_ITER_ENABLED     = (1 << 5),
 381 };
 382
 383 void arch_ftrace_update_code(int command);
 384
 385 struct ftrace_rec_iter;
 386
 387 struct ftrace_rec_iter *ftrace_rec_iter_start(void);
 388 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
 389 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);
 390
 391 #define for_ftrace_rec_iter(iter)               \
 392         for (iter = ftrace_rec_iter_start();    \
 393              iter;                              \
 394              iter = ftrace_rec_iter_next(iter))
 395
 396
 397 int ftrace_update_record(struct dyn_ftrace *rec, int enable);
 398 int ftrace_test_record(struct dyn_ftrace *rec, int enable);
 399 void ftrace_run_stop_machine(int command);
 400 unsigned long ftrace_location(unsigned long ip);
 401 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec);
 402 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec);
 403
 404 extern ftrace_func_t ftrace_trace_function;
 405
 406 int ftrace_regex_open(struct ftrace_ops *ops, int flag,
 407                   struct inode *inode, struct file *file);
 408 ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 409                             size_t cnt, loff_t *ppos);
 410 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 411                              size_t cnt, loff_t *ppos);
 412 int ftrace_regex_release(struct inode *inode, struct file *file);
 413
 414 void __init
 415 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
 416
 417 /* defined in arch */
 418 extern int ftrace_ip_converted(unsigned long ip);
 419 extern int ftrace_dyn_arch_init(void);
 420 extern void ftrace_replace_code(int enable);
 421 extern int ftrace_update_ftrace_func(ftrace_func_t func);
 422 extern void ftrace_caller(void);
 423 extern void ftrace_regs_caller(void);
 424 extern void ftrace_call(void);
 425 extern void ftrace_regs_call(void);
 426 extern void mcount_call(void);
 427
 428 void ftrace_modify_all_code(int command);
 429
 430 #ifndef FTRACE_ADDR
 431 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
 432 #endif
 433
 434 #ifndef FTRACE_REGS_ADDR
 435 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 436 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller)
 437 #else
 438 # define FTRACE_REGS_ADDR FTRACE_ADDR
 439 #endif
 440 #endif
 441
 442 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 443 extern void ftrace_graph_caller(void);
 444 extern int ftrace_enable_ftrace_graph_caller(void);
 445 extern int ftrace_disable_ftrace_graph_caller(void);
 446 #else
 447 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
 448 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
 449 #endif
 450
 451 /**
 452  * ftrace_make_nop - convert code into nop
 453  * @mod: module structure if called by module load initialization
 454  * @rec: the mcount call site record
 455  * @addr: the address that the call site should be calling
 456  *
 457  * This is a very sensitive operation and great care needs
 458  * to be taken by the arch.  The operation should carefully
 459  * read the location, check to see if what is read is indeed
 460  * what we expect it to be, and then on success of the compare,
 461  * it should write to the location.
 462  *
 463  * The code segment at @rec->ip should be a caller to @addr
 464  *
 465  * Return must be:
 466  *  0 on success
 467  *  -EFAULT on error reading the location
 468  *  -EINVAL on a failed compare of the contents
 469  *  -EPERM  on error writing to the location
 470  * Any other value will be considered a failure.
 471  */
 472 extern int ftrace_make_nop(struct module *mod,
 473                            struct dyn_ftrace *rec, unsigned long addr);
 474
 475 /**
 476  * ftrace_make_call - convert a nop call site into a call to addr
 477  * @rec: the mcount call site record
 478  * @addr: the address that the call site should call
 479  *
 480  * This is a very sensitive operation and great care needs
 481  * to be taken by the arch.  The operation should carefully
 482  * read the location, check to see if what is read is indeed
 483  * what we expect it to be, and then on success of the compare,
 484  * it should write to the location.
 485  *
 486  * The code segment at @rec->ip should be a nop
 487  *
 488  * Return must be:
 489  *  0 on success
 490  *  -EFAULT on error reading the location
 491  *  -EINVAL on a failed compare of the contents
 492  *  -EPERM  on error writing to the location
 493  * Any other value will be considered a failure.
 494  */
 495 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
 496
 497 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 498 /**
 499  * ftrace_modify_call - convert from one addr to another (no nop)
 500  * @rec: the mcount call site record
 501  * @old_addr: the address expected to be currently called to
 502  * @addr: the address to change to
 503  *
 504  * This is a very sensitive operation and great care needs
 505  * to be taken by the arch.  The operation should carefully
 506  * read the location, check to see if what is read is indeed
 507  * what we expect it to be, and then on success of the compare,
 508  * it should write to the location.
 509  *
 510  * The code segment at @rec->ip should be a caller to @old_addr
 511  *
 512  * Return must be:
 513  *  0 on success
 514  *  -EFAULT on error reading the location
 515  *  -EINVAL on a failed compare of the contents
 516  *  -EPERM  on error writing to the location
 517  * Any other value will be considered a failure.
 518  */
 519 extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 520                               unsigned long addr);
 521 #else
 522 /* Should never be called */
 523 static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 524                                      unsigned long addr)
 525 {
 526         return -EINVAL;
 527 }
 528 #endif
 529
 530 /* May be defined in arch */
 531 extern int ftrace_arch_read_dyn_info(char *buf, int size);
 532
 533 extern int skip_trace(unsigned long ip);
 534 extern void ftrace_module_init(struct module *mod);
 535
 536 extern void ftrace_disable_daemon(void);
 537 extern void ftrace_enable_daemon(void);
 538 #else /* CONFIG_DYNAMIC_FTRACE */
 539 static inline int skip_trace(unsigned long ip) { return 0; }
 540 static inline int ftrace_force_update(void) { return 0; }
 541 static inline void ftrace_disable_daemon(void) { }
 542 static inline void ftrace_enable_daemon(void) { }
 543 static inline void ftrace_release_mod(struct module *mod) {}
 544 static inline void ftrace_module_init(struct module *mod) {}
 545 static inline __init int register_ftrace_command(struct ftrace_func_command *cmd)
 546 {
 547         return -EINVAL;
 548 }
 549 static inline __init int unregister_ftrace_command(char *cmd_name)
 550 {
 551         return -EINVAL;
 552 }
 553 static inline int ftrace_text_reserved(const void *start, const void *end)
 554 {
 555         return 0;
 556 }
 557 static inline unsigned long ftrace_location(unsigned long ip)
 558 {
 559         return 0;
 560 }
 561
 562 /*
 563  * Again users of functions that have ftrace_ops may not
 564  * have them defined when ftrace is not enabled, but these
 565  * functions may still be called. Use a macro instead of inline.
 566  */
 567 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
 568 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
 569 #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; })
 570 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
 571 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
 572 #define ftrace_free_filter(ops) do { } while (0)
 573
 574 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 575                             size_t cnt, loff_t *ppos) { return -ENODEV; }
 576 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 577                              size_t cnt, loff_t *ppos) { return -ENODEV; }
 578 static inline int
 579 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
 580 #endif /* CONFIG_DYNAMIC_FTRACE */
 581
 582 /* totally disable ftrace - can not re-enable after this */
 583 void ftrace_kill(void);
 584
 585 static inline void tracer_disable(void)
 586 {
 587 #ifdef CONFIG_FUNCTION_TRACER
 588         ftrace_enabled = 0;
 589 #endif
 590 }
 591
 592 /*
 593  * Ftrace disable/restore without lock. Some synchronization mechanism
 594  * must be used to prevent ftrace_enabled to be changed between
 595  * disable/restore.
 596  */
 597 static inline int __ftrace_enabled_save(void)
 598 {
 599 #ifdef CONFIG_FUNCTION_TRACER
 600         int saved_ftrace_enabled = ftrace_enabled;
 601         ftrace_enabled = 0;
 602         return saved_ftrace_enabled;
 603 #else
 604         return 0;
 605 #endif
 606 }
 607
 608 static inline void __ftrace_enabled_restore(int enabled)
 609 {
 610 #ifdef CONFIG_FUNCTION_TRACER
 611         ftrace_enabled = enabled;
 612 #endif
 613 }
 614
 615 /* All archs should have this, but we define it for consistency */
 616 #ifndef ftrace_return_address0
 617 # define ftrace_return_address0 __builtin_return_address(0)
 618 #endif
 619
 620 /* Archs may use other ways for ADDR1 and beyond */
 621 #ifndef ftrace_return_address
 622 # ifdef CONFIG_FRAME_POINTER
 623 #  define ftrace_return_address(n) __builtin_return_address(n)
 624 # else
 625 #  define ftrace_return_address(n) 0UL
 626 # endif
 627 #endif
 628
 629 #define CALLER_ADDR0 ((unsigned long)ftrace_return_address0)
 630 #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1))
 631 #define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2))
 632 #define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3))
 633 #define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4))
 634 #define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5))
 635 #define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6))
 636
 637 #ifdef CONFIG_IRQSOFF_TRACER
 638   extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
 639   extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
 640 #else
 641   static inline void time_hardirqs_on(unsigned long a0, unsigned long a1) { }
 642   static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { }
 643 #endif
 644
 645 #ifdef CONFIG_PREEMPT_TRACER
 646   extern void trace_preempt_on(unsigned long a0, unsigned long a1);
 647   extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 648 #else
 649 /*
 650  * Use defines instead of static inlines because some arches will make code out
 651  * of the CALLER_ADDR, when we really want these to be a real nop.
 652  */
 653 # define trace_preempt_on(a0, a1) do { } while (0)
 654 # define trace_preempt_off(a0, a1) do { } while (0)
 655 #endif
 656
 657 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 658 extern void ftrace_init(void);
 659 #else
 660 static inline void ftrace_init(void) { }
 661 #endif
 662
 663 /*
 664  * Structure that defines an entry function trace.
 665  */
 666 struct ftrace_graph_ent {
 667         unsigned long func; /* Current function */
 668         int depth;
 669 };
 670
 671 /*
 672  * Structure that defines a return function trace.
 673  */
 674 struct ftrace_graph_ret {
 675         unsigned long func; /* Current function */
 676         unsigned long long calltime;
 677         unsigned long long rettime;
 678         /* Number of functions that overran the depth limit for current task */
 679         unsigned long overrun;
 680         int depth;
 681 };
 682
 683 /* Type of the callback handlers for tracing function graph*/
 684 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
 685 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
 686
 687 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 688
 689 /* for init task */
 690 #define INIT_FTRACE_GRAPH               .ret_stack = NULL,
 691
 692 /*
 693  * Stack of return addresses for functions
 694  * of a thread.
 695  * Used in struct thread_info
 696  */
 697 struct ftrace_ret_stack {
 698         unsigned long ret;
 699         unsigned long func;
 700         unsigned long long calltime;
 701         unsigned long long subtime;
 702         unsigned long fp;
 703 };
 704
 705 /*
 706  * Primary handler of a function return.
 707  * It relays on ftrace_return_to_handler.
 708  * Defined in entry_32/64.S
 709  */
 710 extern void return_to_handler(void);
 711
 712 extern int
 713 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
 714                          unsigned long frame_pointer);
 715
 716 /*
 717  * Sometimes we don't want to trace a function with the function
 718  * graph tracer but we want them to keep traced by the usual function
 719  * tracer if the function graph tracer is not configured.
 720  */
 721 #define __notrace_funcgraph             notrace
 722
 723 /*
 724  * We want to which function is an entrypoint of a hardirq.
 725  * That will help us to put a signal on output.
 726  */
 727 #define __irq_entry              __attribute__((__section__(".irqentry.text")))
 728
 729 /* Limits of hardirq entrypoints */
 730 extern char __irqentry_text_start[];
 731 extern char __irqentry_text_end[];
 732
 733 #define FTRACE_NOTRACE_DEPTH 65536
 734 #define FTRACE_RETFUNC_DEPTH 50
 735 #define FTRACE_RETSTACK_ALLOC_SIZE 32
 736 extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 737                                 trace_func_graph_ent_t entryfunc);
 738
 739 extern void ftrace_graph_stop(void);
 740
 741 /* The current handlers in use */
 742 extern trace_func_graph_ret_t ftrace_graph_return;
 743 extern trace_func_graph_ent_t ftrace_graph_entry;
 744
 745 extern void unregister_ftrace_graph(void);
 746
 747 extern void ftrace_graph_init_task(struct task_struct *t);
 748 extern void ftrace_graph_exit_task(struct task_struct *t);
 749 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
 750
 751 static inline int task_curr_ret_stack(struct task_struct *t)
 752 {
 753         return t->curr_ret_stack;
 754 }
 755
 756 static inline void pause_graph_tracing(void)
 757 {
 758         atomic_inc(&current->tracing_graph_pause);
 759 }
 760
 761 static inline void unpause_graph_tracing(void)
 762 {
 763         atomic_dec(&current->tracing_graph_pause);
 764 }
 765 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */
 766
 767 #define __notrace_funcgraph
 768 #define __irq_entry
 769 #define INIT_FTRACE_GRAPH
 770
 771 static inline void ftrace_graph_init_task(struct task_struct *t) { }
 772 static inline void ftrace_graph_exit_task(struct task_struct *t) { }
 773 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
 774
 775 static inline int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 776                           trace_func_graph_ent_t entryfunc)
 777 {
 778         return -1;
 779 }
 780 static inline void unregister_ftrace_graph(void) { }
 781
 782 static inline int task_curr_ret_stack(struct task_struct *tsk)
 783 {
 784         return -1;
 785 }
 786
 787 static inline void pause_graph_tracing(void) { }
 788 static inline void unpause_graph_tracing(void) { }
 789 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 790
 791 #ifdef CONFIG_TRACING
 792
 793 /* flags for current->trace */
 794 enum {
 795         TSK_TRACE_FL_TRACE_BIT  = 0,
 796         TSK_TRACE_FL_GRAPH_BIT  = 1,
 797 };
 798 enum {
 799         TSK_TRACE_FL_TRACE      = 1 << TSK_TRACE_FL_TRACE_BIT,
 800         TSK_TRACE_FL_GRAPH      = 1 << TSK_TRACE_FL_GRAPH_BIT,
 801 };
 802
 803 static inline void set_tsk_trace_trace(struct task_struct *tsk)
 804 {
 805         set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 806 }
 807
 808 static inline void clear_tsk_trace_trace(struct task_struct *tsk)
 809 {
 810         clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 811 }
 812
 813 static inline int test_tsk_trace_trace(struct task_struct *tsk)
 814 {
 815         return tsk->trace & TSK_TRACE_FL_TRACE;
 816 }
 817
 818 static inline void set_tsk_trace_graph(struct task_struct *tsk)
 819 {
 820         set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 821 }
 822
 823 static inline void clear_tsk_trace_graph(struct task_struct *tsk)
 824 {
 825         clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 826 }
 827
 828 static inline int test_tsk_trace_graph(struct task_struct *tsk)
 829 {
 830         return tsk->trace & TSK_TRACE_FL_GRAPH;
 831 }
 832
 833 enum ftrace_dump_mode;
 834
 835 extern enum ftrace_dump_mode ftrace_dump_on_oops;
 836
 837 extern void disable_trace_on_warning(void);
 838 extern int __disable_trace_on_warning;
 839
 840 #ifdef CONFIG_PREEMPT
 841 #define INIT_TRACE_RECURSION            .trace_recursion = 0,
 842 #endif
 843
 844 #else /* CONFIG_TRACING */
 845 static inline void  disable_trace_on_warning(void) { }
 846 #endif /* CONFIG_TRACING */
 847
 848 #ifndef INIT_TRACE_RECURSION
 849 #define INIT_TRACE_RECURSION
 850 #endif
 851
 852 #ifdef CONFIG_FTRACE_SYSCALLS
 853
 854 unsigned long arch_syscall_addr(int nr);
 855
 856 #endif /* CONFIG_FTRACE_SYSCALLS */
 857
 858 #endif /* _LINUX_FTRACE_H */