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 !ARCH_SUPPORTS_FTRACE_OPS
  37 # define FTRACE_FORCE_LIST_FUNC 1
  38 #else
  39 # define FTRACE_FORCE_LIST_FUNC 0
  40 #endif
  41
  42
  43 struct module;
  44 struct ftrace_hash;
  45
  46 #ifdef CONFIG_FUNCTION_TRACER
  47
  48 extern int ftrace_enabled;
  49 extern int
  50 ftrace_enable_sysctl(struct ctl_table *table, int write,
  51                      void __user *buffer, size_t *lenp,
  52                      loff_t *ppos);
  53
  54 struct ftrace_ops;
  55
  56 typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
  57                               struct ftrace_ops *op, struct pt_regs *regs);
  58
  59 /*
  60  * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are
  61  * set in the flags member.
  62  *
  63  * ENABLED - set/unset when ftrace_ops is registered/unregistered
  64  * DYNAMIC - set when ftrace_ops is registered to denote dynamically
  65  *           allocated ftrace_ops which need special care
  66  * CONTROL - set manualy by ftrace_ops user to denote the ftrace_ops
  67  *           could be controled by following calls:
  68  *             ftrace_function_local_enable
  69  *             ftrace_function_local_disable
  70  * SAVE_REGS - The ftrace_ops wants regs saved at each function called
  71  *            and passed to the callback. If this flag is set, but the
  72  *            architecture does not support passing regs
  73  *            (CONFIG_DYNAMIC_FTRACE_WITH_REGS is not defined), then the
  74  *            ftrace_ops will fail to register, unless the next flag
  75  *            is set.
  76  * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the
  77  *            handler can handle an arch that does not save regs
  78  *            (the handler tests if regs == NULL), then it can set
  79  *            this flag instead. It will not fail registering the ftrace_ops
  80  *            but, the regs field will be NULL if the arch does not support
  81  *            passing regs to the handler.
  82  *            Note, if this flag is set, the SAVE_REGS flag will automatically
  83  *            get set upon registering the ftrace_ops, if the arch supports it.
  84  * RECURSION_SAFE - The ftrace_ops can set this to tell the ftrace infrastructure
  85  *            that the call back has its own recursion protection. If it does
  86  *            not set this, then the ftrace infrastructure will add recursion
  87  *            protection for the caller.
  88  * STUB   - The ftrace_ops is just a place holder.
  89  * INITIALIZED - The ftrace_ops has already been initialized (first use time
  90  *            register_ftrace_function() is called, it will initialized the ops)
  91  * DELETED - The ops are being deleted, do not let them be registered again.
  92  */
  93 enum {
  94         FTRACE_OPS_FL_ENABLED                   = 1 << 0,
  95         FTRACE_OPS_FL_DYNAMIC                   = 1 << 1,
  96         FTRACE_OPS_FL_CONTROL                   = 1 << 2,
  97         FTRACE_OPS_FL_SAVE_REGS                 = 1 << 3,
  98         FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED    = 1 << 4,
  99         FTRACE_OPS_FL_RECURSION_SAFE            = 1 << 5,
 100         FTRACE_OPS_FL_STUB                      = 1 << 6,
 101         FTRACE_OPS_FL_INITIALIZED               = 1 << 7,
 102         FTRACE_OPS_FL_DELETED                   = 1 << 8,
 103 };
 104
 105 #ifdef CONFIG_DYNAMIC_FTRACE
 106 /* The hash used to know what functions callbacks trace */
 107 struct ftrace_ops_hash {
 108         struct ftrace_hash              *notrace_hash;
 109         struct ftrace_hash              *filter_hash;
 110         struct mutex                    regex_lock;
 111 };
 112 #endif
 113
 114 /*
 115  * Note, ftrace_ops can be referenced outside of RCU protection.
 116  * (Although, for perf, the control ops prevent that). If ftrace_ops is
 117  * allocated and not part of kernel core data, the unregistering of it will
 118  * perform a scheduling on all CPUs to make sure that there are no more users.
 119  * Depending on the load of the system that may take a bit of time.
 120  *
 121  * Any private data added must also take care not to be freed and if private
 122  * data is added to a ftrace_ops that is in core code, the user of the
 123  * ftrace_ops must perform a schedule_on_each_cpu() before freeing it.
 124  */
 125 struct ftrace_ops {
 126         ftrace_func_t                   func;
 127         struct ftrace_ops               *next;
 128         unsigned long                   flags;
 129         void                            *private;
 130         int __percpu                    *disabled;
 131 #ifdef CONFIG_DYNAMIC_FTRACE
 132         int                             nr_trampolines;
 133         struct ftrace_ops_hash          local_hash;
 134         struct ftrace_ops_hash          *func_hash;
 135         struct ftrace_hash              *tramp_hash;
 136         unsigned long                   trampoline;
 137 #endif
 138 };
 139
 140 /*
 141  * Type of the current tracing.
 142  */
 143 enum ftrace_tracing_type_t {
 144         FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
 145         FTRACE_TYPE_RETURN,     /* Hook the return of the function */
 146 };
 147
 148 /* Current tracing type, default is FTRACE_TYPE_ENTER */
 149 extern enum ftrace_tracing_type_t ftrace_tracing_type;
 150
 151 /*
 152  * The ftrace_ops must be a static and should also
 153  * be read_mostly.  These functions do modify read_mostly variables
 154  * so use them sparely. Never free an ftrace_op or modify the
 155  * next pointer after it has been registered. Even after unregistering
 156  * it, the next pointer may still be used internally.
 157  */
 158 int register_ftrace_function(struct ftrace_ops *ops);
 159 int unregister_ftrace_function(struct ftrace_ops *ops);
 160 void clear_ftrace_function(void);
 161
 162 /**
 163  * ftrace_function_local_enable - enable controlled ftrace_ops on current cpu
 164  *
 165  * This function enables tracing on current cpu by decreasing
 166  * the per cpu control variable.
 167  * It must be called with preemption disabled and only on ftrace_ops
 168  * registered with FTRACE_OPS_FL_CONTROL. If called without preemption
 169  * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
 170  */
 171 static inline void ftrace_function_local_enable(struct ftrace_ops *ops)
 172 {
 173         if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_CONTROL)))
 174                 return;
 175
 176         (*this_cpu_ptr(ops->disabled))--;
 177 }
 178
 179 /**
 180  * ftrace_function_local_disable - enable controlled ftrace_ops on current cpu
 181  *
 182  * This function enables tracing on current cpu by decreasing
 183  * the per cpu control variable.
 184  * It must be called with preemption disabled and only on ftrace_ops
 185  * registered with FTRACE_OPS_FL_CONTROL. If called without preemption
 186  * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
 187  */
 188 static inline void ftrace_function_local_disable(struct ftrace_ops *ops)
 189 {
 190         if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_CONTROL)))
 191                 return;
 192
 193         (*this_cpu_ptr(ops->disabled))++;
 194 }
 195
 196 /**
 197  * ftrace_function_local_disabled - returns ftrace_ops disabled value
 198  *                                  on current cpu
 199  *
 200  * This function returns value of ftrace_ops::disabled on current cpu.
 201  * It must be called with preemption disabled and only on ftrace_ops
 202  * registered with FTRACE_OPS_FL_CONTROL. If called without preemption
 203  * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
 204  */
 205 static inline int ftrace_function_local_disabled(struct ftrace_ops *ops)
 206 {
 207         WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_CONTROL));
 208         return *this_cpu_ptr(ops->disabled);
 209 }
 210
 211 extern void ftrace_stub(unsigned long a0, unsigned long a1,
 212                         struct ftrace_ops *op, struct pt_regs *regs);
 213
 214 #else /* !CONFIG_FUNCTION_TRACER */
 215 /*
 216  * (un)register_ftrace_function must be a macro since the ops parameter
 217  * must not be evaluated.
 218  */
 219 #define register_ftrace_function(ops) ({ 0; })
 220 #define unregister_ftrace_function(ops) ({ 0; })
 221 static inline int ftrace_nr_registered_ops(void)
 222 {
 223         return 0;
 224 }
 225 static inline void clear_ftrace_function(void) { }
 226 static inline void ftrace_kill(void) { }
 227 #endif /* CONFIG_FUNCTION_TRACER */
 228
 229 #ifdef CONFIG_STACK_TRACER
 230 extern int stack_tracer_enabled;
 231 int
 232 stack_trace_sysctl(struct ctl_table *table, int write,
 233                    void __user *buffer, size_t *lenp,
 234                    loff_t *ppos);
 235 #endif
 236
 237 struct ftrace_func_command {
 238         struct list_head        list;
 239         char                    *name;
 240         int                     (*func)(struct ftrace_hash *hash,
 241                                         char *func, char *cmd,
 242                                         char *params, int enable);
 243 };
 244
 245 #ifdef CONFIG_DYNAMIC_FTRACE
 246
 247 int ftrace_arch_code_modify_prepare(void);
 248 int ftrace_arch_code_modify_post_process(void);
 249
 250 void ftrace_bug(int err, unsigned long ip);
 251
 252 struct seq_file;
 253
 254 struct ftrace_probe_ops {
 255         void                    (*func)(unsigned long ip,
 256                                         unsigned long parent_ip,
 257                                         void **data);
 258         int                     (*init)(struct ftrace_probe_ops *ops,
 259                                         unsigned long ip, void **data);
 260         void                    (*free)(struct ftrace_probe_ops *ops,
 261                                         unsigned long ip, void **data);
 262         int                     (*print)(struct seq_file *m,
 263                                          unsigned long ip,
 264                                          struct ftrace_probe_ops *ops,
 265                                          void *data);
 266 };
 267
 268 extern int
 269 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 270                               void *data);
 271 extern void
 272 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 273                                 void *data);
 274 extern void
 275 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops);
 276 extern void unregister_ftrace_function_probe_all(char *glob);
 277
 278 extern int ftrace_text_reserved(const void *start, const void *end);
 279
 280 extern int ftrace_nr_registered_ops(void);
 281
 282 /*
 283  * The dyn_ftrace record's flags field is split into two parts.
 284  * the first part which is '0-FTRACE_REF_MAX' is a counter of
 285  * the number of callbacks that have registered the function that
 286  * the dyn_ftrace descriptor represents.
 287  *
 288  * The second part is a mask:
 289  *  ENABLED - the function is being traced
 290  *  REGS    - the record wants the function to save regs
 291  *  REGS_EN - the function is set up to save regs.
 292  *
 293  * When a new ftrace_ops is registered and wants a function to save
 294  * pt_regs, the rec->flag REGS is set. When the function has been
 295  * set up to save regs, the REG_EN flag is set. Once a function
 296  * starts saving regs it will do so until all ftrace_ops are removed
 297  * from tracing that function.
 298  */
 299 enum {
 300         FTRACE_FL_ENABLED       = (1UL << 31),
 301         FTRACE_FL_REGS          = (1UL << 30),
 302         FTRACE_FL_REGS_EN       = (1UL << 29),
 303         FTRACE_FL_TRAMP         = (1UL << 28),
 304         FTRACE_FL_TRAMP_EN      = (1UL << 27),
 305 };
 306
 307 #define FTRACE_REF_MAX_SHIFT    27
 308 #define FTRACE_FL_BITS          5
 309 #define FTRACE_FL_MASKED_BITS   ((1UL << FTRACE_FL_BITS) - 1)
 310 #define FTRACE_FL_MASK          (FTRACE_FL_MASKED_BITS << FTRACE_REF_MAX_SHIFT)
 311 #define FTRACE_REF_MAX          ((1UL << FTRACE_REF_MAX_SHIFT) - 1)
 312
 313 #define ftrace_rec_count(rec)   ((rec)->flags & ~FTRACE_FL_MASK)
 314
 315 struct dyn_ftrace {
 316         unsigned long           ip; /* address of mcount call-site */
 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  *  MAKE_NOP         - Stop tracing the function
 353  */
 354 enum {
 355         FTRACE_UPDATE_IGNORE,
 356         FTRACE_UPDATE_MAKE_CALL,
 357         FTRACE_UPDATE_MODIFY_CALL,
 358         FTRACE_UPDATE_MAKE_NOP,
 359 };
 360
 361 enum {
 362         FTRACE_ITER_FILTER      = (1 << 0),
 363         FTRACE_ITER_NOTRACE     = (1 << 1),
 364         FTRACE_ITER_PRINTALL    = (1 << 2),
 365         FTRACE_ITER_DO_HASH     = (1 << 3),
 366         FTRACE_ITER_HASH        = (1 << 4),
 367         FTRACE_ITER_ENABLED     = (1 << 5),
 368 };
 369
 370 void arch_ftrace_update_code(int command);
 371
 372 struct ftrace_rec_iter;
 373
 374 struct ftrace_rec_iter *ftrace_rec_iter_start(void);
 375 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
 376 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);
 377
 378 #define for_ftrace_rec_iter(iter)               \
 379         for (iter = ftrace_rec_iter_start();    \
 380              iter;                              \
 381              iter = ftrace_rec_iter_next(iter))
 382
 383
 384 int ftrace_update_record(struct dyn_ftrace *rec, int enable);
 385 int ftrace_test_record(struct dyn_ftrace *rec, int enable);
 386 void ftrace_run_stop_machine(int command);
 387 unsigned long ftrace_location(unsigned long ip);
 388 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec);
 389 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec);
 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 int ftrace_regex_release(struct inode *inode, struct file *file);
 400
 401 void __init
 402 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
 403
 404 /* defined in arch */
 405 extern int ftrace_ip_converted(unsigned long ip);
 406 extern int ftrace_dyn_arch_init(void);
 407 extern void ftrace_replace_code(int enable);
 408 extern int ftrace_update_ftrace_func(ftrace_func_t func);
 409 extern void ftrace_caller(void);
 410 extern void ftrace_regs_caller(void);
 411 extern void ftrace_call(void);
 412 extern void ftrace_regs_call(void);
 413 extern void mcount_call(void);
 414
 415 void ftrace_modify_all_code(int command);
 416
 417 #ifndef FTRACE_ADDR
 418 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
 419 #endif
 420
 421 #ifndef FTRACE_GRAPH_ADDR
 422 #define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller)
 423 #endif
 424
 425 #ifndef FTRACE_REGS_ADDR
 426 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 427 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller)
 428 #else
 429 # define FTRACE_REGS_ADDR FTRACE_ADDR
 430 #endif
 431 #endif
 432
 433 /*
 434  * If an arch would like functions that are only traced
 435  * by the function graph tracer to jump directly to its own
 436  * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR
 437  * to be that address to jump to.
 438  */
 439 #ifndef FTRACE_GRAPH_TRAMP_ADDR
 440 #define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0)
 441 #endif
 442
 443 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 444 extern void ftrace_graph_caller(void);
 445 extern int ftrace_enable_ftrace_graph_caller(void);
 446 extern int ftrace_disable_ftrace_graph_caller(void);
 447 #else
 448 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
 449 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
 450 #endif
 451
 452 /**
 453  * ftrace_make_nop - convert code into nop
 454  * @mod: module structure if called by module load initialization
 455  * @rec: the mcount call site record
 456  * @addr: the address that the call site should be calling
 457  *
 458  * This is a very sensitive operation and great care needs
 459  * to be taken by the arch.  The operation should carefully
 460  * read the location, check to see if what is read is indeed
 461  * what we expect it to be, and then on success of the compare,
 462  * it should write to the location.
 463  *
 464  * The code segment at @rec->ip should be a caller to @addr
 465  *
 466  * Return must be:
 467  *  0 on success
 468  *  -EFAULT on error reading the location
 469  *  -EINVAL on a failed compare of the contents
 470  *  -EPERM  on error writing to the location
 471  * Any other value will be considered a failure.
 472  */
 473 extern int ftrace_make_nop(struct module *mod,
 474                            struct dyn_ftrace *rec, unsigned long addr);
 475
 476 /**
 477  * ftrace_make_call - convert a nop call site into a call to addr
 478  * @rec: the mcount call site record
 479  * @addr: the address that the call site should call
 480  *
 481  * This is a very sensitive operation and great care needs
 482  * to be taken by the arch.  The operation should carefully
 483  * read the location, check to see if what is read is indeed
 484  * what we expect it to be, and then on success of the compare,
 485  * it should write to the location.
 486  *
 487  * The code segment at @rec->ip should be a nop
 488  *
 489  * Return must be:
 490  *  0 on success
 491  *  -EFAULT on error reading the location
 492  *  -EINVAL on a failed compare of the contents
 493  *  -EPERM  on error writing to the location
 494  * Any other value will be considered a failure.
 495  */
 496 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
 497
 498 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 499 /**
 500  * ftrace_modify_call - convert from one addr to another (no nop)
 501  * @rec: the mcount call site record
 502  * @old_addr: the address expected to be currently called to
 503  * @addr: the address to change to
 504  *
 505  * This is a very sensitive operation and great care needs
 506  * to be taken by the arch.  The operation should carefully
 507  * read the location, check to see if what is read is indeed
 508  * what we expect it to be, and then on success of the compare,
 509  * it should write to the location.
 510  *
 511  * The code segment at @rec->ip should be a caller to @old_addr
 512  *
 513  * Return must be:
 514  *  0 on success
 515  *  -EFAULT on error reading the location
 516  *  -EINVAL on a failed compare of the contents
 517  *  -EPERM  on error writing to the location
 518  * Any other value will be considered a failure.
 519  */
 520 extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 521                               unsigned long addr);
 522 #else
 523 /* Should never be called */
 524 static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 525                                      unsigned long addr)
 526 {
 527         return -EINVAL;
 528 }
 529 #endif
 530
 531 /* May be defined in arch */
 532 extern int ftrace_arch_read_dyn_info(char *buf, int size);
 533
 534 extern int skip_trace(unsigned long ip);
 535 extern void ftrace_module_init(struct module *mod);
 536
 537 extern void ftrace_disable_daemon(void);
 538 extern void ftrace_enable_daemon(void);
 539 #else /* CONFIG_DYNAMIC_FTRACE */
 540 static inline int skip_trace(unsigned long ip) { return 0; }
 541 static inline int ftrace_force_update(void) { return 0; }
 542 static inline void ftrace_disable_daemon(void) { }
 543 static inline void ftrace_enable_daemon(void) { }
 544 static inline void ftrace_release_mod(struct module *mod) {}
 545 static inline void ftrace_module_init(struct module *mod) {}
 546 static inline __init int register_ftrace_command(struct ftrace_func_command *cmd)
 547 {
 548         return -EINVAL;
 549 }
 550 static inline __init int unregister_ftrace_command(char *cmd_name)
 551 {
 552         return -EINVAL;
 553 }
 554 static inline int ftrace_text_reserved(const void *start, const void *end)
 555 {
 556         return 0;
 557 }
 558 static inline unsigned long ftrace_location(unsigned long ip)
 559 {
 560         return 0;
 561 }
 562
 563 /*
 564  * Again users of functions that have ftrace_ops may not
 565  * have them defined when ftrace is not enabled, but these
 566  * functions may still be called. Use a macro instead of inline.
 567  */
 568 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
 569 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
 570 #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; })
 571 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
 572 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
 573 #define ftrace_free_filter(ops) do { } while (0)
 574
 575 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 576                             size_t cnt, loff_t *ppos) { return -ENODEV; }
 577 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 578                              size_t cnt, loff_t *ppos) { return -ENODEV; }
 579 static inline int
 580 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
 581 #endif /* CONFIG_DYNAMIC_FTRACE */
 582
 583 /* totally disable ftrace - can not re-enable after this */
 584 void ftrace_kill(void);
 585
 586 static inline void tracer_disable(void)
 587 {
 588 #ifdef CONFIG_FUNCTION_TRACER
 589         ftrace_enabled = 0;
 590 #endif
 591 }
 592
 593 /*
 594  * Ftrace disable/restore without lock. Some synchronization mechanism
 595  * must be used to prevent ftrace_enabled to be changed between
 596  * disable/restore.
 597  */
 598 static inline int __ftrace_enabled_save(void)
 599 {
 600 #ifdef CONFIG_FUNCTION_TRACER
 601         int saved_ftrace_enabled = ftrace_enabled;
 602         ftrace_enabled = 0;
 603         return saved_ftrace_enabled;
 604 #else
 605         return 0;
 606 #endif
 607 }
 608
 609 static inline void __ftrace_enabled_restore(int enabled)
 610 {
 611 #ifdef CONFIG_FUNCTION_TRACER
 612         ftrace_enabled = enabled;
 613 #endif
 614 }
 615
 616 /* All archs should have this, but we define it for consistency */
 617 #ifndef ftrace_return_address0
 618 # define ftrace_return_address0 __builtin_return_address(0)
 619 #endif
 620
 621 /* Archs may use other ways for ADDR1 and beyond */
 622 #ifndef ftrace_return_address
 623 # ifdef CONFIG_FRAME_POINTER
 624 #  define ftrace_return_address(n) __builtin_return_address(n)
 625 # else
 626 #  define ftrace_return_address(n) 0UL
 627 # endif
 628 #endif
 629
 630 #define CALLER_ADDR0 ((unsigned long)ftrace_return_address0)
 631 #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1))
 632 #define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2))
 633 #define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3))
 634 #define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4))
 635 #define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5))
 636 #define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6))
 637
 638 #ifdef CONFIG_IRQSOFF_TRACER
 639   extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
 640   extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
 641 #else
 642   static inline void time_hardirqs_on(unsigned long a0, unsigned long a1) { }
 643   static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { }
 644 #endif
 645
 646 #ifdef CONFIG_PREEMPT_TRACER
 647   extern void trace_preempt_on(unsigned long a0, unsigned long a1);
 648   extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 649 #else
 650 /*
 651  * Use defines instead of static inlines because some arches will make code out
 652  * of the CALLER_ADDR, when we really want these to be a real nop.
 653  */
 654 # define trace_preempt_on(a0, a1) do { } while (0)
 655 # define trace_preempt_off(a0, a1) do { } while (0)
 656 #endif
 657
 658 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 659 extern void ftrace_init(void);
 660 #else
 661 static inline void ftrace_init(void) { }
 662 #endif
 663
 664 /*
 665  * Structure that defines an entry function trace.
 666  */
 667 struct ftrace_graph_ent {
 668         unsigned long func; /* Current function */
 669         int depth;
 670 };
 671
 672 /*
 673  * Structure that defines a return function trace.
 674  */
 675 struct ftrace_graph_ret {
 676         unsigned long func; /* Current function */
 677         unsigned long long calltime;
 678         unsigned long long rettime;
 679         /* Number of functions that overran the depth limit for current task */
 680         unsigned long overrun;
 681         int depth;
 682 };
 683
 684 /* Type of the callback handlers for tracing function graph*/
 685 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
 686 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
 687
 688 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 689
 690 /* for init task */
 691 #define INIT_FTRACE_GRAPH               .ret_stack = NULL,
 692
 693 /*
 694  * Stack of return addresses for functions
 695  * of a thread.
 696  * Used in struct thread_info
 697  */
 698 struct ftrace_ret_stack {
 699         unsigned long ret;
 700         unsigned long func;
 701         unsigned long long calltime;
 702         unsigned long long subtime;
 703         unsigned long fp;
 704 };
 705
 706 /*
 707  * Primary handler of a function return.
 708  * It relays on ftrace_return_to_handler.
 709  * Defined in entry_32/64.S
 710  */
 711 extern void return_to_handler(void);
 712
 713 extern int
 714 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
 715                          unsigned long frame_pointer);
 716
 717 /*
 718  * Sometimes we don't want to trace a function with the function
 719  * graph tracer but we want them to keep traced by the usual function
 720  * tracer if the function graph tracer is not configured.
 721  */
 722 #define __notrace_funcgraph             notrace
 723
 724 /*
 725  * We want to which function is an entrypoint of a hardirq.
 726  * That will help us to put a signal on output.
 727  */
 728 #define __irq_entry              __attribute__((__section__(".irqentry.text")))
 729
 730 /* Limits of hardirq entrypoints */
 731 extern char __irqentry_text_start[];
 732 extern char __irqentry_text_end[];
 733
 734 #define FTRACE_NOTRACE_DEPTH 65536
 735 #define FTRACE_RETFUNC_DEPTH 50
 736 #define FTRACE_RETSTACK_ALLOC_SIZE 32
 737 extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 738                                 trace_func_graph_ent_t entryfunc);
 739
 740 extern bool ftrace_graph_is_dead(void);
 741 extern void ftrace_graph_stop(void);
 742
 743 /* The current handlers in use */
 744 extern trace_func_graph_ret_t ftrace_graph_return;
 745 extern trace_func_graph_ent_t ftrace_graph_entry;
 746
 747 extern void unregister_ftrace_graph(void);
 748
 749 extern void ftrace_graph_init_task(struct task_struct *t);
 750 extern void ftrace_graph_exit_task(struct task_struct *t);
 751 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
 752
 753 static inline int task_curr_ret_stack(struct task_struct *t)
 754 {
 755         return t->curr_ret_stack;
 756 }
 757
 758 static inline void pause_graph_tracing(void)
 759 {
 760         atomic_inc(&current->tracing_graph_pause);
 761 }
 762
 763 static inline void unpause_graph_tracing(void)
 764 {
 765         atomic_dec(&current->tracing_graph_pause);
 766 }
 767 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */
 768
 769 #define __notrace_funcgraph
 770 #define __irq_entry
 771 #define INIT_FTRACE_GRAPH
 772
 773 static inline void ftrace_graph_init_task(struct task_struct *t) { }
 774 static inline void ftrace_graph_exit_task(struct task_struct *t) { }
 775 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
 776
 777 static inline int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 778                           trace_func_graph_ent_t entryfunc)
 779 {
 780         return -1;
 781 }
 782 static inline void unregister_ftrace_graph(void) { }
 783
 784 static inline int task_curr_ret_stack(struct task_struct *tsk)
 785 {
 786         return -1;
 787 }
 788
 789 static inline void pause_graph_tracing(void) { }
 790 static inline void unpause_graph_tracing(void) { }
 791 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 792
 793 #ifdef CONFIG_TRACING
 794
 795 /* flags for current->trace */
 796 enum {
 797         TSK_TRACE_FL_TRACE_BIT  = 0,
 798         TSK_TRACE_FL_GRAPH_BIT  = 1,
 799 };
 800 enum {
 801         TSK_TRACE_FL_TRACE      = 1 << TSK_TRACE_FL_TRACE_BIT,
 802         TSK_TRACE_FL_GRAPH      = 1 << TSK_TRACE_FL_GRAPH_BIT,
 803 };
 804
 805 static inline void set_tsk_trace_trace(struct task_struct *tsk)
 806 {
 807         set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 808 }
 809
 810 static inline void clear_tsk_trace_trace(struct task_struct *tsk)
 811 {
 812         clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 813 }
 814
 815 static inline int test_tsk_trace_trace(struct task_struct *tsk)
 816 {
 817         return tsk->trace & TSK_TRACE_FL_TRACE;
 818 }
 819
 820 static inline void set_tsk_trace_graph(struct task_struct *tsk)
 821 {
 822         set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 823 }
 824
 825 static inline void clear_tsk_trace_graph(struct task_struct *tsk)
 826 {
 827         clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 828 }
 829
 830 static inline int test_tsk_trace_graph(struct task_struct *tsk)
 831 {
 832         return tsk->trace & TSK_TRACE_FL_GRAPH;
 833 }
 834
 835 enum ftrace_dump_mode;
 836
 837 extern enum ftrace_dump_mode ftrace_dump_on_oops;
 838
 839 extern void disable_trace_on_warning(void);
 840 extern int __disable_trace_on_warning;
 841
 842 #ifdef CONFIG_PREEMPT
 843 #define INIT_TRACE_RECURSION            .trace_recursion = 0,
 844 #endif
 845
 846 #else /* CONFIG_TRACING */
 847 static inline void  disable_trace_on_warning(void) { }
 848 #endif /* CONFIG_TRACING */
 849
 850 #ifndef INIT_TRACE_RECURSION
 851 #define INIT_TRACE_RECURSION
 852 #endif
 853
 854 #ifdef CONFIG_FTRACE_SYSCALLS
 855
 856 unsigned long arch_syscall_addr(int nr);
 857
 858 #endif /* CONFIG_FTRACE_SYSCALLS */
 859
 860 #endif /* _LINUX_FTRACE_H */