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 /* Main tracing buffer and events set up */
  43 #ifdef CONFIG_TRACING
  44 void trace_init(void);
  45 #else
  46 static inline void trace_init(void) { }
  47 #endif
  48
  49 struct module;
  50 struct ftrace_hash;
  51
  52 #ifdef CONFIG_FUNCTION_TRACER
  53
  54 extern int ftrace_enabled;
  55 extern int
  56 ftrace_enable_sysctl(struct ctl_table *table, int write,
  57                      void __user *buffer, size_t *lenp,
  58                      loff_t *ppos);
  59
  60 struct ftrace_ops;
  61
  62 typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
  63                               struct ftrace_ops *op, struct pt_regs *regs);
  64
  65 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops);
  66
  67 /*
  68  * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are
  69  * set in the flags member.
  70  * CONTROL, SAVE_REGS, SAVE_REGS_IF_SUPPORTED, RECURSION_SAFE, STUB and
  71  * IPMODIFY are a kind of attribute flags which can be set only before
  72  * registering the ftrace_ops, and can not be modified while registered.
  73  * Changing those attribute flags after regsitering ftrace_ops will
  74  * cause unexpected results.
  75  *
  76  * ENABLED - set/unset when ftrace_ops is registered/unregistered
  77  * DYNAMIC - set when ftrace_ops is registered to denote dynamically
  78  *           allocated ftrace_ops which need special care
  79  * CONTROL - set manualy by ftrace_ops user to denote the ftrace_ops
  80  *           could be controled by following calls:
  81  *             ftrace_function_local_enable
  82  *             ftrace_function_local_disable
  83  * SAVE_REGS - The ftrace_ops wants regs saved at each function called
  84  *            and passed to the callback. If this flag is set, but the
  85  *            architecture does not support passing regs
  86  *            (CONFIG_DYNAMIC_FTRACE_WITH_REGS is not defined), then the
  87  *            ftrace_ops will fail to register, unless the next flag
  88  *            is set.
  89  * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the
  90  *            handler can handle an arch that does not save regs
  91  *            (the handler tests if regs == NULL), then it can set
  92  *            this flag instead. It will not fail registering the ftrace_ops
  93  *            but, the regs field will be NULL if the arch does not support
  94  *            passing regs to the handler.
  95  *            Note, if this flag is set, the SAVE_REGS flag will automatically
  96  *            get set upon registering the ftrace_ops, if the arch supports it.
  97  * RECURSION_SAFE - The ftrace_ops can set this to tell the ftrace infrastructure
  98  *            that the call back has its own recursion protection. If it does
  99  *            not set this, then the ftrace infrastructure will add recursion
 100  *            protection for the caller.
 101  * STUB   - The ftrace_ops is just a place holder.
 102  * INITIALIZED - The ftrace_ops has already been initialized (first use time
 103  *            register_ftrace_function() is called, it will initialized the ops)
 104  * DELETED - The ops are being deleted, do not let them be registered again.
 105  * ADDING  - The ops is in the process of being added.
 106  * REMOVING - The ops is in the process of being removed.
 107  * MODIFYING - The ops is in the process of changing its filter functions.
 108  * ALLOC_TRAMP - A dynamic trampoline was allocated by the core code.
 109  *            The arch specific code sets this flag when it allocated a
 110  *            trampoline. This lets the arch know that it can update the
 111  *            trampoline in case the callback function changes.
 112  *            The ftrace_ops trampoline can be set by the ftrace users, and
 113  *            in such cases the arch must not modify it. Only the arch ftrace
 114  *            core code should set this flag.
 115  * IPMODIFY - The ops can modify the IP register. This can only be set with
 116  *            SAVE_REGS. If another ops with this flag set is already registered
 117  *            for any of the functions that this ops will be registered for, then
 118  *            this ops will fail to register or set_filter_ip.
 119  * PID     - Is affected by set_ftrace_pid (allows filtering on those pids)
 120  */
 121 enum {
 122         FTRACE_OPS_FL_ENABLED                   = 1 << 0,
 123         FTRACE_OPS_FL_DYNAMIC                   = 1 << 1,
 124         FTRACE_OPS_FL_CONTROL                   = 1 << 2,
 125         FTRACE_OPS_FL_SAVE_REGS                 = 1 << 3,
 126         FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED    = 1 << 4,
 127         FTRACE_OPS_FL_RECURSION_SAFE            = 1 << 5,
 128         FTRACE_OPS_FL_STUB                      = 1 << 6,
 129         FTRACE_OPS_FL_INITIALIZED               = 1 << 7,
 130         FTRACE_OPS_FL_DELETED                   = 1 << 8,
 131         FTRACE_OPS_FL_ADDING                    = 1 << 9,
 132         FTRACE_OPS_FL_REMOVING                  = 1 << 10,
 133         FTRACE_OPS_FL_MODIFYING                 = 1 << 11,
 134         FTRACE_OPS_FL_ALLOC_TRAMP               = 1 << 12,
 135         FTRACE_OPS_FL_IPMODIFY                  = 1 << 13,
 136         FTRACE_OPS_FL_PID                       = 1 << 14,
 137 };
 138
 139 #ifdef CONFIG_DYNAMIC_FTRACE
 140 /* The hash used to know what functions callbacks trace */
 141 struct ftrace_ops_hash {
 142         struct ftrace_hash              *notrace_hash;
 143         struct ftrace_hash              *filter_hash;
 144         struct mutex                    regex_lock;
 145 };
 146 #endif
 147
 148 /*
 149  * Note, ftrace_ops can be referenced outside of RCU protection.
 150  * (Although, for perf, the control ops prevent that). If ftrace_ops is
 151  * allocated and not part of kernel core data, the unregistering of it will
 152  * perform a scheduling on all CPUs to make sure that there are no more users.
 153  * Depending on the load of the system that may take a bit of time.
 154  *
 155  * Any private data added must also take care not to be freed and if private
 156  * data is added to a ftrace_ops that is in core code, the user of the
 157  * ftrace_ops must perform a schedule_on_each_cpu() before freeing it.
 158  */
 159 struct ftrace_ops {
 160         ftrace_func_t                   func;
 161         struct ftrace_ops               *next;
 162         unsigned long                   flags;
 163         void                            *private;
 164         ftrace_func_t                   saved_func;
 165         int __percpu                    *disabled;
 166 #ifdef CONFIG_DYNAMIC_FTRACE
 167         int                             nr_trampolines;
 168         struct ftrace_ops_hash          local_hash;
 169         struct ftrace_ops_hash          *func_hash;
 170         struct ftrace_ops_hash          old_hash;
 171         unsigned long                   trampoline;
 172         unsigned long                   trampoline_size;
 173 #endif
 174 };
 175
 176 /*
 177  * Type of the current tracing.
 178  */
 179 enum ftrace_tracing_type_t {
 180         FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
 181         FTRACE_TYPE_RETURN,     /* Hook the return of the function */
 182 };
 183
 184 /* Current tracing type, default is FTRACE_TYPE_ENTER */
 185 extern enum ftrace_tracing_type_t ftrace_tracing_type;
 186
 187 /*
 188  * The ftrace_ops must be a static and should also
 189  * be read_mostly.  These functions do modify read_mostly variables
 190  * so use them sparely. Never free an ftrace_op or modify the
 191  * next pointer after it has been registered. Even after unregistering
 192  * it, the next pointer may still be used internally.
 193  */
 194 int register_ftrace_function(struct ftrace_ops *ops);
 195 int unregister_ftrace_function(struct ftrace_ops *ops);
 196 void clear_ftrace_function(void);
 197
 198 /**
 199  * ftrace_function_local_enable - enable controlled ftrace_ops on current cpu
 200  *
 201  * This function enables tracing on current cpu by decreasing
 202  * the per cpu control variable.
 203  * It must be called with preemption disabled and only on ftrace_ops
 204  * registered with FTRACE_OPS_FL_CONTROL. If called without preemption
 205  * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
 206  */
 207 static inline void ftrace_function_local_enable(struct ftrace_ops *ops)
 208 {
 209         if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_CONTROL)))
 210                 return;
 211
 212         (*this_cpu_ptr(ops->disabled))--;
 213 }
 214
 215 /**
 216  * ftrace_function_local_disable - enable controlled ftrace_ops on current cpu
 217  *
 218  * This function enables tracing on current cpu by decreasing
 219  * the per cpu control variable.
 220  * It must be called with preemption disabled and only on ftrace_ops
 221  * registered with FTRACE_OPS_FL_CONTROL. If called without preemption
 222  * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
 223  */
 224 static inline void ftrace_function_local_disable(struct ftrace_ops *ops)
 225 {
 226         if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_CONTROL)))
 227                 return;
 228
 229         (*this_cpu_ptr(ops->disabled))++;
 230 }
 231
 232 /**
 233  * ftrace_function_local_disabled - returns ftrace_ops disabled value
 234  *                                  on current cpu
 235  *
 236  * This function returns value of ftrace_ops::disabled on current cpu.
 237  * It must be called with preemption disabled and only on ftrace_ops
 238  * registered with FTRACE_OPS_FL_CONTROL. If called without preemption
 239  * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
 240  */
 241 static inline int ftrace_function_local_disabled(struct ftrace_ops *ops)
 242 {
 243         WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_CONTROL));
 244         return *this_cpu_ptr(ops->disabled);
 245 }
 246
 247 extern void ftrace_stub(unsigned long a0, unsigned long a1,
 248                         struct ftrace_ops *op, struct pt_regs *regs);
 249
 250 #else /* !CONFIG_FUNCTION_TRACER */
 251 /*
 252  * (un)register_ftrace_function must be a macro since the ops parameter
 253  * must not be evaluated.
 254  */
 255 #define register_ftrace_function(ops) ({ 0; })
 256 #define unregister_ftrace_function(ops) ({ 0; })
 257 static inline int ftrace_nr_registered_ops(void)
 258 {
 259         return 0;
 260 }
 261 static inline void clear_ftrace_function(void) { }
 262 static inline void ftrace_kill(void) { }
 263 #endif /* CONFIG_FUNCTION_TRACER */
 264
 265 #ifdef CONFIG_STACK_TRACER
 266
 267 #define STACK_TRACE_ENTRIES 500
 268
 269 struct stack_trace;
 270
 271 extern unsigned stack_trace_index[];
 272 extern struct stack_trace stack_trace_max;
 273 extern unsigned long stack_trace_max_size;
 274 extern arch_spinlock_t stack_trace_max_lock;
 275
 276 extern int stack_tracer_enabled;
 277 void stack_trace_print(void);
 278 int
 279 stack_trace_sysctl(struct ctl_table *table, int write,
 280                    void __user *buffer, size_t *lenp,
 281                    loff_t *ppos);
 282 #endif
 283
 284 struct ftrace_func_command {
 285         struct list_head        list;
 286         char                    *name;
 287         int                     (*func)(struct ftrace_hash *hash,
 288                                         char *func, char *cmd,
 289                                         char *params, int enable);
 290 };
 291
 292 #ifdef CONFIG_DYNAMIC_FTRACE
 293
 294 int ftrace_arch_code_modify_prepare(void);
 295 int ftrace_arch_code_modify_post_process(void);
 296
 297 struct dyn_ftrace;
 298
 299 void ftrace_bug(int err, struct dyn_ftrace *rec);
 300
 301 struct seq_file;
 302
 303 struct ftrace_probe_ops {
 304         void                    (*func)(unsigned long ip,
 305                                         unsigned long parent_ip,
 306                                         void **data);
 307         int                     (*init)(struct ftrace_probe_ops *ops,
 308                                         unsigned long ip, void **data);
 309         void                    (*free)(struct ftrace_probe_ops *ops,
 310                                         unsigned long ip, void **data);
 311         int                     (*print)(struct seq_file *m,
 312                                          unsigned long ip,
 313                                          struct ftrace_probe_ops *ops,
 314                                          void *data);
 315 };
 316
 317 extern int
 318 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 319                               void *data);
 320 extern void
 321 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 322                                 void *data);
 323 extern void
 324 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops);
 325 extern void unregister_ftrace_function_probe_all(char *glob);
 326
 327 extern int ftrace_text_reserved(const void *start, const void *end);
 328
 329 extern int ftrace_nr_registered_ops(void);
 330
 331 bool is_ftrace_trampoline(unsigned long addr);
 332
 333 /*
 334  * The dyn_ftrace record's flags field is split into two parts.
 335  * the first part which is '0-FTRACE_REF_MAX' is a counter of
 336  * the number of callbacks that have registered the function that
 337  * the dyn_ftrace descriptor represents.
 338  *
 339  * The second part is a mask:
 340  *  ENABLED - the function is being traced
 341  *  REGS    - the record wants the function to save regs
 342  *  REGS_EN - the function is set up to save regs.
 343  *  IPMODIFY - the record allows for the IP address to be changed.
 344  *
 345  * When a new ftrace_ops is registered and wants a function to save
 346  * pt_regs, the rec->flag REGS is set. When the function has been
 347  * set up to save regs, the REG_EN flag is set. Once a function
 348  * starts saving regs it will do so until all ftrace_ops are removed
 349  * from tracing that function.
 350  */
 351 enum {
 352         FTRACE_FL_ENABLED       = (1UL << 31),
 353         FTRACE_FL_REGS          = (1UL << 30),
 354         FTRACE_FL_REGS_EN       = (1UL << 29),
 355         FTRACE_FL_TRAMP         = (1UL << 28),
 356         FTRACE_FL_TRAMP_EN      = (1UL << 27),
 357         FTRACE_FL_IPMODIFY      = (1UL << 26),
 358 };
 359
 360 #define FTRACE_REF_MAX_SHIFT    26
 361 #define FTRACE_FL_BITS          6
 362 #define FTRACE_FL_MASKED_BITS   ((1UL << FTRACE_FL_BITS) - 1)
 363 #define FTRACE_FL_MASK          (FTRACE_FL_MASKED_BITS << FTRACE_REF_MAX_SHIFT)
 364 #define FTRACE_REF_MAX          ((1UL << FTRACE_REF_MAX_SHIFT) - 1)
 365
 366 #define ftrace_rec_count(rec)   ((rec)->flags & ~FTRACE_FL_MASK)
 367
 368 struct dyn_ftrace {
 369         unsigned long           ip; /* address of mcount call-site */
 370         unsigned long           flags;
 371         struct dyn_arch_ftrace  arch;
 372 };
 373
 374 int ftrace_force_update(void);
 375 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
 376                          int remove, int reset);
 377 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
 378                        int len, int reset);
 379 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
 380                         int len, int reset);
 381 void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
 382 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
 383 void ftrace_free_filter(struct ftrace_ops *ops);
 384
 385 int register_ftrace_command(struct ftrace_func_command *cmd);
 386 int unregister_ftrace_command(struct ftrace_func_command *cmd);
 387
 388 enum {
 389         FTRACE_UPDATE_CALLS             = (1 << 0),
 390         FTRACE_DISABLE_CALLS            = (1 << 1),
 391         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
 392         FTRACE_START_FUNC_RET           = (1 << 3),
 393         FTRACE_STOP_FUNC_RET            = (1 << 4),
 394 };
 395
 396 /*
 397  * The FTRACE_UPDATE_* enum is used to pass information back
 398  * from the ftrace_update_record() and ftrace_test_record()
 399  * functions. These are called by the code update routines
 400  * to find out what is to be done for a given function.
 401  *
 402  *  IGNORE           - The function is already what we want it to be
 403  *  MAKE_CALL        - Start tracing the function
 404  *  MODIFY_CALL      - Stop saving regs for the function
 405  *  MAKE_NOP         - Stop tracing the function
 406  */
 407 enum {
 408         FTRACE_UPDATE_IGNORE,
 409         FTRACE_UPDATE_MAKE_CALL,
 410         FTRACE_UPDATE_MODIFY_CALL,
 411         FTRACE_UPDATE_MAKE_NOP,
 412 };
 413
 414 enum {
 415         FTRACE_ITER_FILTER      = (1 << 0),
 416         FTRACE_ITER_NOTRACE     = (1 << 1),
 417         FTRACE_ITER_PRINTALL    = (1 << 2),
 418         FTRACE_ITER_DO_HASH     = (1 << 3),
 419         FTRACE_ITER_HASH        = (1 << 4),
 420         FTRACE_ITER_ENABLED     = (1 << 5),
 421 };
 422
 423 void arch_ftrace_update_code(int command);
 424
 425 struct ftrace_rec_iter;
 426
 427 struct ftrace_rec_iter *ftrace_rec_iter_start(void);
 428 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
 429 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);
 430
 431 #define for_ftrace_rec_iter(iter)               \
 432         for (iter = ftrace_rec_iter_start();    \
 433              iter;                              \
 434              iter = ftrace_rec_iter_next(iter))
 435
 436
 437 int ftrace_update_record(struct dyn_ftrace *rec, int enable);
 438 int ftrace_test_record(struct dyn_ftrace *rec, int enable);
 439 void ftrace_run_stop_machine(int command);
 440 unsigned long ftrace_location(unsigned long ip);
 441 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec);
 442 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec);
 443
 444 extern ftrace_func_t ftrace_trace_function;
 445
 446 int ftrace_regex_open(struct ftrace_ops *ops, int flag,
 447                   struct inode *inode, struct file *file);
 448 ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 449                             size_t cnt, loff_t *ppos);
 450 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 451                              size_t cnt, loff_t *ppos);
 452 int ftrace_regex_release(struct inode *inode, struct file *file);
 453
 454 void __init
 455 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
 456
 457 /* defined in arch */
 458 extern int ftrace_ip_converted(unsigned long ip);
 459 extern int ftrace_dyn_arch_init(void);
 460 extern void ftrace_replace_code(int enable);
 461 extern int ftrace_update_ftrace_func(ftrace_func_t func);
 462 extern void ftrace_caller(void);
 463 extern void ftrace_regs_caller(void);
 464 extern void ftrace_call(void);
 465 extern void ftrace_regs_call(void);
 466 extern void mcount_call(void);
 467
 468 void ftrace_modify_all_code(int command);
 469
 470 #ifndef FTRACE_ADDR
 471 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
 472 #endif
 473
 474 #ifndef FTRACE_GRAPH_ADDR
 475 #define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller)
 476 #endif
 477
 478 #ifndef FTRACE_REGS_ADDR
 479 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 480 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller)
 481 #else
 482 # define FTRACE_REGS_ADDR FTRACE_ADDR
 483 #endif
 484 #endif
 485
 486 /*
 487  * If an arch would like functions that are only traced
 488  * by the function graph tracer to jump directly to its own
 489  * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR
 490  * to be that address to jump to.
 491  */
 492 #ifndef FTRACE_GRAPH_TRAMP_ADDR
 493 #define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0)
 494 #endif
 495
 496 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 497 extern void ftrace_graph_caller(void);
 498 extern int ftrace_enable_ftrace_graph_caller(void);
 499 extern int ftrace_disable_ftrace_graph_caller(void);
 500 #else
 501 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
 502 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
 503 #endif
 504
 505 /**
 506  * ftrace_make_nop - convert code into nop
 507  * @mod: module structure if called by module load initialization
 508  * @rec: the mcount call site record
 509  * @addr: the address that the call site should be calling
 510  *
 511  * This is a very sensitive operation and great care needs
 512  * to be taken by the arch.  The operation should carefully
 513  * read the location, check to see if what is read is indeed
 514  * what we expect it to be, and then on success of the compare,
 515  * it should write to the location.
 516  *
 517  * The code segment at @rec->ip should be a caller to @addr
 518  *
 519  * Return must be:
 520  *  0 on success
 521  *  -EFAULT on error reading the location
 522  *  -EINVAL on a failed compare of the contents
 523  *  -EPERM  on error writing to the location
 524  * Any other value will be considered a failure.
 525  */
 526 extern int ftrace_make_nop(struct module *mod,
 527                            struct dyn_ftrace *rec, unsigned long addr);
 528
 529 /**
 530  * ftrace_make_call - convert a nop call site into a call to addr
 531  * @rec: the mcount call site record
 532  * @addr: the address that the call site should call
 533  *
 534  * This is a very sensitive operation and great care needs
 535  * to be taken by the arch.  The operation should carefully
 536  * read the location, check to see if what is read is indeed
 537  * what we expect it to be, and then on success of the compare,
 538  * it should write to the location.
 539  *
 540  * The code segment at @rec->ip should be a nop
 541  *
 542  * Return must be:
 543  *  0 on success
 544  *  -EFAULT on error reading the location
 545  *  -EINVAL on a failed compare of the contents
 546  *  -EPERM  on error writing to the location
 547  * Any other value will be considered a failure.
 548  */
 549 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
 550
 551 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 552 /**
 553  * ftrace_modify_call - convert from one addr to another (no nop)
 554  * @rec: the mcount call site record
 555  * @old_addr: the address expected to be currently called to
 556  * @addr: the address to change to
 557  *
 558  * This is a very sensitive operation and great care needs
 559  * to be taken by the arch.  The operation should carefully
 560  * read the location, check to see if what is read is indeed
 561  * what we expect it to be, and then on success of the compare,
 562  * it should write to the location.
 563  *
 564  * The code segment at @rec->ip should be a caller to @old_addr
 565  *
 566  * Return must be:
 567  *  0 on success
 568  *  -EFAULT on error reading the location
 569  *  -EINVAL on a failed compare of the contents
 570  *  -EPERM  on error writing to the location
 571  * Any other value will be considered a failure.
 572  */
 573 extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 574                               unsigned long addr);
 575 #else
 576 /* Should never be called */
 577 static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 578                                      unsigned long addr)
 579 {
 580         return -EINVAL;
 581 }
 582 #endif
 583
 584 /* May be defined in arch */
 585 extern int ftrace_arch_read_dyn_info(char *buf, int size);
 586
 587 extern int skip_trace(unsigned long ip);
 588 extern void ftrace_module_init(struct module *mod);
 589
 590 extern void ftrace_disable_daemon(void);
 591 extern void ftrace_enable_daemon(void);
 592 #else /* CONFIG_DYNAMIC_FTRACE */
 593 static inline int skip_trace(unsigned long ip) { return 0; }
 594 static inline int ftrace_force_update(void) { return 0; }
 595 static inline void ftrace_disable_daemon(void) { }
 596 static inline void ftrace_enable_daemon(void) { }
 597 static inline void ftrace_release_mod(struct module *mod) {}
 598 static inline void ftrace_module_init(struct module *mod) {}
 599 static inline __init int register_ftrace_command(struct ftrace_func_command *cmd)
 600 {
 601         return -EINVAL;
 602 }
 603 static inline __init int unregister_ftrace_command(char *cmd_name)
 604 {
 605         return -EINVAL;
 606 }
 607 static inline int ftrace_text_reserved(const void *start, const void *end)
 608 {
 609         return 0;
 610 }
 611 static inline unsigned long ftrace_location(unsigned long ip)
 612 {
 613         return 0;
 614 }
 615
 616 /*
 617  * Again users of functions that have ftrace_ops may not
 618  * have them defined when ftrace is not enabled, but these
 619  * functions may still be called. Use a macro instead of inline.
 620  */
 621 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
 622 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
 623 #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; })
 624 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
 625 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
 626 #define ftrace_free_filter(ops) do { } while (0)
 627
 628 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 629                             size_t cnt, loff_t *ppos) { return -ENODEV; }
 630 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 631                              size_t cnt, loff_t *ppos) { return -ENODEV; }
 632 static inline int
 633 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
 634
 635 static inline bool is_ftrace_trampoline(unsigned long addr)
 636 {
 637         return false;
 638 }
 639 #endif /* CONFIG_DYNAMIC_FTRACE */
 640
 641 /* totally disable ftrace - can not re-enable after this */
 642 void ftrace_kill(void);
 643
 644 static inline void tracer_disable(void)
 645 {
 646 #ifdef CONFIG_FUNCTION_TRACER
 647         ftrace_enabled = 0;
 648 #endif
 649 }
 650
 651 /*
 652  * Ftrace disable/restore without lock. Some synchronization mechanism
 653  * must be used to prevent ftrace_enabled to be changed between
 654  * disable/restore.
 655  */
 656 static inline int __ftrace_enabled_save(void)
 657 {
 658 #ifdef CONFIG_FUNCTION_TRACER
 659         int saved_ftrace_enabled = ftrace_enabled;
 660         ftrace_enabled = 0;
 661         return saved_ftrace_enabled;
 662 #else
 663         return 0;
 664 #endif
 665 }
 666
 667 static inline void __ftrace_enabled_restore(int enabled)
 668 {
 669 #ifdef CONFIG_FUNCTION_TRACER
 670         ftrace_enabled = enabled;
 671 #endif
 672 }
 673
 674 /* All archs should have this, but we define it for consistency */
 675 #ifndef ftrace_return_address0
 676 # define ftrace_return_address0 __builtin_return_address(0)
 677 #endif
 678
 679 /* Archs may use other ways for ADDR1 and beyond */
 680 #ifndef ftrace_return_address
 681 # ifdef CONFIG_FRAME_POINTER
 682 #  define ftrace_return_address(n) __builtin_return_address(n)
 683 # else
 684 #  define ftrace_return_address(n) 0UL
 685 # endif
 686 #endif
 687
 688 #define CALLER_ADDR0 ((unsigned long)ftrace_return_address0)
 689 #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1))
 690 #define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2))
 691 #define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3))
 692 #define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4))
 693 #define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5))
 694 #define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6))
 695
 696 #ifdef CONFIG_IRQSOFF_TRACER
 697   extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
 698   extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
 699 #else
 700   static inline void time_hardirqs_on(unsigned long a0, unsigned long a1) { }
 701   static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { }
 702 #endif
 703
 704 #ifdef CONFIG_PREEMPT_TRACER
 705   extern void trace_preempt_on(unsigned long a0, unsigned long a1);
 706   extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 707 #else
 708 /*
 709  * Use defines instead of static inlines because some arches will make code out
 710  * of the CALLER_ADDR, when we really want these to be a real nop.
 711  */
 712 # define trace_preempt_on(a0, a1) do { } while (0)
 713 # define trace_preempt_off(a0, a1) do { } while (0)
 714 #endif
 715
 716 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 717 extern void ftrace_init(void);
 718 #else
 719 static inline void ftrace_init(void) { }
 720 #endif
 721
 722 /*
 723  * Structure that defines an entry function trace.
 724  */
 725 struct ftrace_graph_ent {
 726         unsigned long func; /* Current function */
 727         int depth;
 728 };
 729
 730 /*
 731  * Structure that defines a return function trace.
 732  */
 733 struct ftrace_graph_ret {
 734         unsigned long func; /* Current function */
 735         unsigned long long calltime;
 736         unsigned long long rettime;
 737         /* Number of functions that overran the depth limit for current task */
 738         unsigned long overrun;
 739         int depth;
 740 };
 741
 742 /* Type of the callback handlers for tracing function graph*/
 743 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
 744 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
 745
 746 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 747
 748 /* for init task */
 749 #define INIT_FTRACE_GRAPH               .ret_stack = NULL,
 750
 751 /*
 752  * Stack of return addresses for functions
 753  * of a thread.
 754  * Used in struct thread_info
 755  */
 756 struct ftrace_ret_stack {
 757         unsigned long ret;
 758         unsigned long func;
 759         unsigned long long calltime;
 760         unsigned long long subtime;
 761         unsigned long fp;
 762 };
 763
 764 /*
 765  * Primary handler of a function return.
 766  * It relays on ftrace_return_to_handler.
 767  * Defined in entry_32/64.S
 768  */
 769 extern void return_to_handler(void);
 770
 771 extern int
 772 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
 773                          unsigned long frame_pointer);
 774
 775 /*
 776  * Sometimes we don't want to trace a function with the function
 777  * graph tracer but we want them to keep traced by the usual function
 778  * tracer if the function graph tracer is not configured.
 779  */
 780 #define __notrace_funcgraph             notrace
 781
 782 /*
 783  * We want to which function is an entrypoint of a hardirq.
 784  * That will help us to put a signal on output.
 785  */
 786 #define __irq_entry              __attribute__((__section__(".irqentry.text")))
 787
 788 /* Limits of hardirq entrypoints */
 789 extern char __irqentry_text_start[];
 790 extern char __irqentry_text_end[];
 791
 792 #define FTRACE_NOTRACE_DEPTH 65536
 793 #define FTRACE_RETFUNC_DEPTH 50
 794 #define FTRACE_RETSTACK_ALLOC_SIZE 32
 795 extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 796                                 trace_func_graph_ent_t entryfunc);
 797
 798 extern bool ftrace_graph_is_dead(void);
 799 extern void ftrace_graph_stop(void);
 800
 801 /* The current handlers in use */
 802 extern trace_func_graph_ret_t ftrace_graph_return;
 803 extern trace_func_graph_ent_t ftrace_graph_entry;
 804
 805 extern void unregister_ftrace_graph(void);
 806
 807 extern void ftrace_graph_init_task(struct task_struct *t);
 808 extern void ftrace_graph_exit_task(struct task_struct *t);
 809 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
 810
 811 static inline int task_curr_ret_stack(struct task_struct *t)
 812 {
 813         return t->curr_ret_stack;
 814 }
 815
 816 static inline void pause_graph_tracing(void)
 817 {
 818         atomic_inc(&current->tracing_graph_pause);
 819 }
 820
 821 static inline void unpause_graph_tracing(void)
 822 {
 823         atomic_dec(&current->tracing_graph_pause);
 824 }
 825 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */
 826
 827 #define __notrace_funcgraph
 828 #define __irq_entry
 829 #define INIT_FTRACE_GRAPH
 830
 831 static inline void ftrace_graph_init_task(struct task_struct *t) { }
 832 static inline void ftrace_graph_exit_task(struct task_struct *t) { }
 833 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
 834
 835 static inline int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 836                           trace_func_graph_ent_t entryfunc)
 837 {
 838         return -1;
 839 }
 840 static inline void unregister_ftrace_graph(void) { }
 841
 842 static inline int task_curr_ret_stack(struct task_struct *tsk)
 843 {
 844         return -1;
 845 }
 846
 847 static inline void pause_graph_tracing(void) { }
 848 static inline void unpause_graph_tracing(void) { }
 849 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 850
 851 #ifdef CONFIG_TRACING
 852
 853 /* flags for current->trace */
 854 enum {
 855         TSK_TRACE_FL_TRACE_BIT  = 0,
 856         TSK_TRACE_FL_GRAPH_BIT  = 1,
 857 };
 858 enum {
 859         TSK_TRACE_FL_TRACE      = 1 << TSK_TRACE_FL_TRACE_BIT,
 860         TSK_TRACE_FL_GRAPH      = 1 << TSK_TRACE_FL_GRAPH_BIT,
 861 };
 862
 863 static inline void set_tsk_trace_trace(struct task_struct *tsk)
 864 {
 865         set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 866 }
 867
 868 static inline void clear_tsk_trace_trace(struct task_struct *tsk)
 869 {
 870         clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 871 }
 872
 873 static inline int test_tsk_trace_trace(struct task_struct *tsk)
 874 {
 875         return tsk->trace & TSK_TRACE_FL_TRACE;
 876 }
 877
 878 static inline void set_tsk_trace_graph(struct task_struct *tsk)
 879 {
 880         set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 881 }
 882
 883 static inline void clear_tsk_trace_graph(struct task_struct *tsk)
 884 {
 885         clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 886 }
 887
 888 static inline int test_tsk_trace_graph(struct task_struct *tsk)
 889 {
 890         return tsk->trace & TSK_TRACE_FL_GRAPH;
 891 }
 892
 893 enum ftrace_dump_mode;
 894
 895 extern enum ftrace_dump_mode ftrace_dump_on_oops;
 896 extern int tracepoint_printk;
 897
 898 extern void disable_trace_on_warning(void);
 899 extern int __disable_trace_on_warning;
 900
 901 #ifdef CONFIG_PREEMPT
 902 #define INIT_TRACE_RECURSION            .trace_recursion = 0,
 903 #endif
 904
 905 #else /* CONFIG_TRACING */
 906 static inline void  disable_trace_on_warning(void) { }
 907 #endif /* CONFIG_TRACING */
 908
 909 #ifndef INIT_TRACE_RECURSION
 910 #define INIT_TRACE_RECURSION
 911 #endif
 912
 913 #ifdef CONFIG_FTRACE_SYSCALLS
 914
 915 unsigned long arch_syscall_addr(int nr);
 916
 917 #endif /* CONFIG_FTRACE_SYSCALLS */
 918
 919 #endif /* _LINUX_FTRACE_H */