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  * PER_CPU - set manualy by ftrace_ops user to denote the ftrace_ops
  80  *           could be controlled 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_PER_CPU                   = 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         FTRACE_OPS_FL_RCU                       = 1 << 15,
 138 };
 139
 140 #ifdef CONFIG_DYNAMIC_FTRACE
 141 /* The hash used to know what functions callbacks trace */
 142 struct ftrace_ops_hash {
 143         struct ftrace_hash              *notrace_hash;
 144         struct ftrace_hash              *filter_hash;
 145         struct mutex                    regex_lock;
 146 };
 147 #endif
 148
 149 /*
 150  * Note, ftrace_ops can be referenced outside of RCU protection, unless
 151  * the RCU flag is set. If ftrace_ops is allocated and not part of kernel
 152  * core data, the unregistering of it will perform a scheduling on all CPUs
 153  * to make sure that there are no more users. Depending on the load of the
 154  * system that may take a bit of time.
 155  *
 156  * Any private data added must also take care not to be freed and if private
 157  * data is added to a ftrace_ops that is in core code, the user of the
 158  * ftrace_ops must perform a schedule_on_each_cpu() before freeing it.
 159  */
 160 struct ftrace_ops {
 161         ftrace_func_t                   func;
 162         struct ftrace_ops               *next;
 163         unsigned long                   flags;
 164         void                            *private;
 165         ftrace_func_t                   saved_func;
 166         int __percpu                    *disabled;
 167 #ifdef CONFIG_DYNAMIC_FTRACE
 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 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_PER_CPU. 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_PER_CPU)))
 210                 return;
 211
 212         (*this_cpu_ptr(ops->disabled))--;
 213 }
 214
 215 /**
 216  * ftrace_function_local_disable - disable ftrace_ops on current cpu
 217  *
 218  * This function disables tracing on current cpu by increasing
 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_PER_CPU. 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_PER_CPU)))
 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_PER_CPU. 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_PER_CPU));
 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 enum ftrace_bug_type {
 300         FTRACE_BUG_UNKNOWN,
 301         FTRACE_BUG_INIT,
 302         FTRACE_BUG_NOP,
 303         FTRACE_BUG_CALL,
 304         FTRACE_BUG_UPDATE,
 305 };
 306 extern enum ftrace_bug_type ftrace_bug_type;
 307
 308 /*
 309  * Archs can set this to point to a variable that holds the value that was
 310  * expected at the call site before calling ftrace_bug().
 311  */
 312 extern const void *ftrace_expected;
 313
 314 void ftrace_bug(int err, struct dyn_ftrace *rec);
 315
 316 struct seq_file;
 317
 318 struct ftrace_probe_ops {
 319         void                    (*func)(unsigned long ip,
 320                                         unsigned long parent_ip,
 321                                         void **data);
 322         int                     (*init)(struct ftrace_probe_ops *ops,
 323                                         unsigned long ip, void **data);
 324         void                    (*free)(struct ftrace_probe_ops *ops,
 325                                         unsigned long ip, void **data);
 326         int                     (*print)(struct seq_file *m,
 327                                          unsigned long ip,
 328                                          struct ftrace_probe_ops *ops,
 329                                          void *data);
 330 };
 331
 332 extern int
 333 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 334                               void *data);
 335 extern void
 336 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 337                                 void *data);
 338 extern void
 339 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops);
 340 extern void unregister_ftrace_function_probe_all(char *glob);
 341
 342 extern int ftrace_text_reserved(const void *start, const void *end);
 343
 344 extern int ftrace_nr_registered_ops(void);
 345
 346 bool is_ftrace_trampoline(unsigned long addr);
 347
 348 /*
 349  * The dyn_ftrace record's flags field is split into two parts.
 350  * the first part which is '0-FTRACE_REF_MAX' is a counter of
 351  * the number of callbacks that have registered the function that
 352  * the dyn_ftrace descriptor represents.
 353  *
 354  * The second part is a mask:
 355  *  ENABLED - the function is being traced
 356  *  REGS    - the record wants the function to save regs
 357  *  REGS_EN - the function is set up to save regs.
 358  *  IPMODIFY - the record allows for the IP address to be changed.
 359  *  DISABLED - the record is not ready to be touched yet
 360  *
 361  * When a new ftrace_ops is registered and wants a function to save
 362  * pt_regs, the rec->flag REGS is set. When the function has been
 363  * set up to save regs, the REG_EN flag is set. Once a function
 364  * starts saving regs it will do so until all ftrace_ops are removed
 365  * from tracing that function.
 366  */
 367 enum {
 368         FTRACE_FL_ENABLED       = (1UL << 31),
 369         FTRACE_FL_REGS          = (1UL << 30),
 370         FTRACE_FL_REGS_EN       = (1UL << 29),
 371         FTRACE_FL_TRAMP         = (1UL << 28),
 372         FTRACE_FL_TRAMP_EN      = (1UL << 27),
 373         FTRACE_FL_IPMODIFY      = (1UL << 26),
 374         FTRACE_FL_DISABLED      = (1UL << 25),
 375 };
 376
 377 #define FTRACE_REF_MAX_SHIFT    25
 378 #define FTRACE_FL_BITS          7
 379 #define FTRACE_FL_MASKED_BITS   ((1UL << FTRACE_FL_BITS) - 1)
 380 #define FTRACE_FL_MASK          (FTRACE_FL_MASKED_BITS << FTRACE_REF_MAX_SHIFT)
 381 #define FTRACE_REF_MAX          ((1UL << FTRACE_REF_MAX_SHIFT) - 1)
 382
 383 #define ftrace_rec_count(rec)   ((rec)->flags & ~FTRACE_FL_MASK)
 384
 385 struct dyn_ftrace {
 386         unsigned long           ip; /* address of mcount call-site */
 387         unsigned long           flags;
 388         struct dyn_arch_ftrace  arch;
 389 };
 390
 391 int ftrace_force_update(void);
 392 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
 393                          int remove, int reset);
 394 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
 395                        int len, int reset);
 396 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
 397                         int len, int reset);
 398 void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
 399 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
 400 void ftrace_free_filter(struct ftrace_ops *ops);
 401 void ftrace_ops_set_global_filter(struct ftrace_ops *ops);
 402
 403 int register_ftrace_command(struct ftrace_func_command *cmd);
 404 int unregister_ftrace_command(struct ftrace_func_command *cmd);
 405
 406 enum {
 407         FTRACE_UPDATE_CALLS             = (1 << 0),
 408         FTRACE_DISABLE_CALLS            = (1 << 1),
 409         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
 410         FTRACE_START_FUNC_RET           = (1 << 3),
 411         FTRACE_STOP_FUNC_RET            = (1 << 4),
 412 };
 413
 414 /*
 415  * The FTRACE_UPDATE_* enum is used to pass information back
 416  * from the ftrace_update_record() and ftrace_test_record()
 417  * functions. These are called by the code update routines
 418  * to find out what is to be done for a given function.
 419  *
 420  *  IGNORE           - The function is already what we want it to be
 421  *  MAKE_CALL        - Start tracing the function
 422  *  MODIFY_CALL      - Stop saving regs for the function
 423  *  MAKE_NOP         - Stop tracing the function
 424  */
 425 enum {
 426         FTRACE_UPDATE_IGNORE,
 427         FTRACE_UPDATE_MAKE_CALL,
 428         FTRACE_UPDATE_MODIFY_CALL,
 429         FTRACE_UPDATE_MAKE_NOP,
 430 };
 431
 432 enum {
 433         FTRACE_ITER_FILTER      = (1 << 0),
 434         FTRACE_ITER_NOTRACE     = (1 << 1),
 435         FTRACE_ITER_PRINTALL    = (1 << 2),
 436         FTRACE_ITER_DO_HASH     = (1 << 3),
 437         FTRACE_ITER_HASH        = (1 << 4),
 438         FTRACE_ITER_ENABLED     = (1 << 5),
 439 };
 440
 441 void arch_ftrace_update_code(int command);
 442
 443 struct ftrace_rec_iter;
 444
 445 struct ftrace_rec_iter *ftrace_rec_iter_start(void);
 446 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
 447 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);
 448
 449 #define for_ftrace_rec_iter(iter)               \
 450         for (iter = ftrace_rec_iter_start();    \
 451              iter;                              \
 452              iter = ftrace_rec_iter_next(iter))
 453
 454
 455 int ftrace_update_record(struct dyn_ftrace *rec, int enable);
 456 int ftrace_test_record(struct dyn_ftrace *rec, int enable);
 457 void ftrace_run_stop_machine(int command);
 458 unsigned long ftrace_location(unsigned long ip);
 459 unsigned long ftrace_location_range(unsigned long start, unsigned long end);
 460 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec);
 461 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec);
 462
 463 extern ftrace_func_t ftrace_trace_function;
 464
 465 int ftrace_regex_open(struct ftrace_ops *ops, int flag,
 466                   struct inode *inode, struct file *file);
 467 ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 468                             size_t cnt, loff_t *ppos);
 469 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 470                              size_t cnt, loff_t *ppos);
 471 int ftrace_regex_release(struct inode *inode, struct file *file);
 472
 473 void __init
 474 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
 475
 476 /* defined in arch */
 477 extern int ftrace_ip_converted(unsigned long ip);
 478 extern int ftrace_dyn_arch_init(void);
 479 extern void ftrace_replace_code(int enable);
 480 extern int ftrace_update_ftrace_func(ftrace_func_t func);
 481 extern void ftrace_caller(void);
 482 extern void ftrace_regs_caller(void);
 483 extern void ftrace_call(void);
 484 extern void ftrace_regs_call(void);
 485 extern void mcount_call(void);
 486
 487 void ftrace_modify_all_code(int command);
 488
 489 #ifndef FTRACE_ADDR
 490 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
 491 #endif
 492
 493 #ifndef FTRACE_GRAPH_ADDR
 494 #define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller)
 495 #endif
 496
 497 #ifndef FTRACE_REGS_ADDR
 498 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 499 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller)
 500 #else
 501 # define FTRACE_REGS_ADDR FTRACE_ADDR
 502 #endif
 503 #endif
 504
 505 /*
 506  * If an arch would like functions that are only traced
 507  * by the function graph tracer to jump directly to its own
 508  * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR
 509  * to be that address to jump to.
 510  */
 511 #ifndef FTRACE_GRAPH_TRAMP_ADDR
 512 #define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0)
 513 #endif
 514
 515 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 516 extern void ftrace_graph_caller(void);
 517 extern int ftrace_enable_ftrace_graph_caller(void);
 518 extern int ftrace_disable_ftrace_graph_caller(void);
 519 #else
 520 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
 521 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
 522 #endif
 523
 524 /**
 525  * ftrace_make_nop - convert code into nop
 526  * @mod: module structure if called by module load initialization
 527  * @rec: the mcount call site record
 528  * @addr: the address that the call site should be calling
 529  *
 530  * This is a very sensitive operation and great care needs
 531  * to be taken by the arch.  The operation should carefully
 532  * read the location, check to see if what is read is indeed
 533  * what we expect it to be, and then on success of the compare,
 534  * it should write to the location.
 535  *
 536  * The code segment at @rec->ip should be a caller to @addr
 537  *
 538  * Return must be:
 539  *  0 on success
 540  *  -EFAULT on error reading the location
 541  *  -EINVAL on a failed compare of the contents
 542  *  -EPERM  on error writing to the location
 543  * Any other value will be considered a failure.
 544  */
 545 extern int ftrace_make_nop(struct module *mod,
 546                            struct dyn_ftrace *rec, unsigned long addr);
 547
 548 /**
 549  * ftrace_make_call - convert a nop call site into a call to addr
 550  * @rec: the mcount call site record
 551  * @addr: the address that the call site should call
 552  *
 553  * This is a very sensitive operation and great care needs
 554  * to be taken by the arch.  The operation should carefully
 555  * read the location, check to see if what is read is indeed
 556  * what we expect it to be, and then on success of the compare,
 557  * it should write to the location.
 558  *
 559  * The code segment at @rec->ip should be a nop
 560  *
 561  * Return must be:
 562  *  0 on success
 563  *  -EFAULT on error reading the location
 564  *  -EINVAL on a failed compare of the contents
 565  *  -EPERM  on error writing to the location
 566  * Any other value will be considered a failure.
 567  */
 568 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
 569
 570 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 571 /**
 572  * ftrace_modify_call - convert from one addr to another (no nop)
 573  * @rec: the mcount call site record
 574  * @old_addr: the address expected to be currently called to
 575  * @addr: the address to change to
 576  *
 577  * This is a very sensitive operation and great care needs
 578  * to be taken by the arch.  The operation should carefully
 579  * read the location, check to see if what is read is indeed
 580  * what we expect it to be, and then on success of the compare,
 581  * it should write to the location.
 582  *
 583  * The code segment at @rec->ip should be a caller to @old_addr
 584  *
 585  * Return must be:
 586  *  0 on success
 587  *  -EFAULT on error reading the location
 588  *  -EINVAL on a failed compare of the contents
 589  *  -EPERM  on error writing to the location
 590  * Any other value will be considered a failure.
 591  */
 592 extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 593                               unsigned long addr);
 594 #else
 595 /* Should never be called */
 596 static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 597                                      unsigned long addr)
 598 {
 599         return -EINVAL;
 600 }
 601 #endif
 602
 603 /* May be defined in arch */
 604 extern int ftrace_arch_read_dyn_info(char *buf, int size);
 605
 606 extern int skip_trace(unsigned long ip);
 607 extern void ftrace_module_init(struct module *mod);
 608 extern void ftrace_module_enable(struct module *mod);
 609 extern void ftrace_release_mod(struct module *mod);
 610
 611 extern void ftrace_disable_daemon(void);
 612 extern void ftrace_enable_daemon(void);
 613 #else /* CONFIG_DYNAMIC_FTRACE */
 614 static inline int skip_trace(unsigned long ip) { return 0; }
 615 static inline int ftrace_force_update(void) { return 0; }
 616 static inline void ftrace_disable_daemon(void) { }
 617 static inline void ftrace_enable_daemon(void) { }
 618 static inline void ftrace_module_init(struct module *mod) { }
 619 static inline void ftrace_module_enable(struct module *mod) { }
 620 static inline void ftrace_release_mod(struct module *mod) { }
 621 static inline __init int register_ftrace_command(struct ftrace_func_command *cmd)
 622 {
 623         return -EINVAL;
 624 }
 625 static inline __init int unregister_ftrace_command(char *cmd_name)
 626 {
 627         return -EINVAL;
 628 }
 629 static inline int ftrace_text_reserved(const void *start, const void *end)
 630 {
 631         return 0;
 632 }
 633 static inline unsigned long ftrace_location(unsigned long ip)
 634 {
 635         return 0;
 636 }
 637
 638 /*
 639  * Again users of functions that have ftrace_ops may not
 640  * have them defined when ftrace is not enabled, but these
 641  * functions may still be called. Use a macro instead of inline.
 642  */
 643 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
 644 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
 645 #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; })
 646 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
 647 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
 648 #define ftrace_free_filter(ops) do { } while (0)
 649 #define ftrace_ops_set_global_filter(ops) do { } while (0)
 650
 651 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 652                             size_t cnt, loff_t *ppos) { return -ENODEV; }
 653 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 654                              size_t cnt, loff_t *ppos) { return -ENODEV; }
 655 static inline int
 656 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
 657
 658 static inline bool is_ftrace_trampoline(unsigned long addr)
 659 {
 660         return false;
 661 }
 662 #endif /* CONFIG_DYNAMIC_FTRACE */
 663
 664 /* totally disable ftrace - can not re-enable after this */
 665 void ftrace_kill(void);
 666
 667 static inline void tracer_disable(void)
 668 {
 669 #ifdef CONFIG_FUNCTION_TRACER
 670         ftrace_enabled = 0;
 671 #endif
 672 }
 673
 674 /*
 675  * Ftrace disable/restore without lock. Some synchronization mechanism
 676  * must be used to prevent ftrace_enabled to be changed between
 677  * disable/restore.
 678  */
 679 static inline int __ftrace_enabled_save(void)
 680 {
 681 #ifdef CONFIG_FUNCTION_TRACER
 682         int saved_ftrace_enabled = ftrace_enabled;
 683         ftrace_enabled = 0;
 684         return saved_ftrace_enabled;
 685 #else
 686         return 0;
 687 #endif
 688 }
 689
 690 static inline void __ftrace_enabled_restore(int enabled)
 691 {
 692 #ifdef CONFIG_FUNCTION_TRACER
 693         ftrace_enabled = enabled;
 694 #endif
 695 }
 696
 697 /* All archs should have this, but we define it for consistency */
 698 #ifndef ftrace_return_address0
 699 # define ftrace_return_address0 __builtin_return_address(0)
 700 #endif
 701
 702 /* Archs may use other ways for ADDR1 and beyond */
 703 #ifndef ftrace_return_address
 704 # ifdef CONFIG_FRAME_POINTER
 705 #  define ftrace_return_address(n) __builtin_return_address(n)
 706 # else
 707 #  define ftrace_return_address(n) 0UL
 708 # endif
 709 #endif
 710
 711 #define CALLER_ADDR0 ((unsigned long)ftrace_return_address0)
 712 #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1))
 713 #define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2))
 714 #define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3))
 715 #define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4))
 716 #define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5))
 717 #define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6))
 718
 719 static inline unsigned long get_lock_parent_ip(void)
 720 {
 721         unsigned long addr = CALLER_ADDR0;
 722
 723         if (!in_lock_functions(addr))
 724                 return addr;
 725         addr = CALLER_ADDR1;
 726         if (!in_lock_functions(addr))
 727                 return addr;
 728         return CALLER_ADDR2;
 729 }
 730
 731 #ifdef CONFIG_IRQSOFF_TRACER
 732   extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
 733   extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
 734 #else
 735   static inline void time_hardirqs_on(unsigned long a0, unsigned long a1) { }
 736   static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { }
 737 #endif
 738
 739 #ifdef CONFIG_PREEMPT_TRACER
 740   extern void trace_preempt_on(unsigned long a0, unsigned long a1);
 741   extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 742 #else
 743 /*
 744  * Use defines instead of static inlines because some arches will make code out
 745  * of the CALLER_ADDR, when we really want these to be a real nop.
 746  */
 747 # define trace_preempt_on(a0, a1) do { } while (0)
 748 # define trace_preempt_off(a0, a1) do { } while (0)
 749 #endif
 750
 751 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 752 extern void ftrace_init(void);
 753 #else
 754 static inline void ftrace_init(void) { }
 755 #endif
 756
 757 /*
 758  * Structure that defines an entry function trace.
 759  * It's already packed but the attribute "packed" is needed
 760  * to remove extra padding at the end.
 761  */
 762 struct ftrace_graph_ent {
 763         unsigned long func; /* Current function */
 764         int depth;
 765 } __packed;
 766
 767 /*
 768  * Structure that defines a return function trace.
 769  * It's already packed but the attribute "packed" is needed
 770  * to remove extra padding at the end.
 771  */
 772 struct ftrace_graph_ret {
 773         unsigned long func; /* Current function */
 774         /* Number of functions that overran the depth limit for current task */
 775         unsigned long overrun;
 776         unsigned long long calltime;
 777         unsigned long long rettime;
 778         int depth;
 779 } __packed;
 780
 781 /* Type of the callback handlers for tracing function graph*/
 782 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
 783 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
 784
 785 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 786
 787 /* for init task */
 788 #define INIT_FTRACE_GRAPH               .ret_stack = NULL,
 789
 790 /*
 791  * Stack of return addresses for functions
 792  * of a thread.
 793  * Used in struct thread_info
 794  */
 795 struct ftrace_ret_stack {
 796         unsigned long ret;
 797         unsigned long func;
 798         unsigned long long calltime;
 799 #ifdef CONFIG_FUNCTION_PROFILER
 800         unsigned long long subtime;
 801 #endif
 802 #ifdef HAVE_FUNCTION_GRAPH_FP_TEST
 803         unsigned long fp;
 804 #endif
 805 #ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
 806         unsigned long *retp;
 807 #endif
 808 };
 809
 810 /*
 811  * Primary handler of a function return.
 812  * It relays on ftrace_return_to_handler.
 813  * Defined in entry_32/64.S
 814  */
 815 extern void return_to_handler(void);
 816
 817 extern int
 818 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
 819                          unsigned long frame_pointer, unsigned long *retp);
 820
 821 unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
 822                                     unsigned long ret, unsigned long *retp);
 823
 824 /*
 825  * Sometimes we don't want to trace a function with the function
 826  * graph tracer but we want them to keep traced by the usual function
 827  * tracer if the function graph tracer is not configured.
 828  */
 829 #define __notrace_funcgraph             notrace
 830
 831 #define FTRACE_NOTRACE_DEPTH 65536
 832 #define FTRACE_RETFUNC_DEPTH 50
 833 #define FTRACE_RETSTACK_ALLOC_SIZE 32
 834 extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 835                                 trace_func_graph_ent_t entryfunc);
 836
 837 extern bool ftrace_graph_is_dead(void);
 838 extern void ftrace_graph_stop(void);
 839
 840 /* The current handlers in use */
 841 extern trace_func_graph_ret_t ftrace_graph_return;
 842 extern trace_func_graph_ent_t ftrace_graph_entry;
 843
 844 extern void unregister_ftrace_graph(void);
 845
 846 extern void ftrace_graph_init_task(struct task_struct *t);
 847 extern void ftrace_graph_exit_task(struct task_struct *t);
 848 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
 849
 850 static inline int task_curr_ret_stack(struct task_struct *t)
 851 {
 852         return t->curr_ret_stack;
 853 }
 854
 855 static inline void pause_graph_tracing(void)
 856 {
 857         atomic_inc(&current->tracing_graph_pause);
 858 }
 859
 860 static inline void unpause_graph_tracing(void)
 861 {
 862         atomic_dec(&current->tracing_graph_pause);
 863 }
 864 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */
 865
 866 #define __notrace_funcgraph
 867 #define INIT_FTRACE_GRAPH
 868
 869 static inline void ftrace_graph_init_task(struct task_struct *t) { }
 870 static inline void ftrace_graph_exit_task(struct task_struct *t) { }
 871 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
 872
 873 static inline int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 874                           trace_func_graph_ent_t entryfunc)
 875 {
 876         return -1;
 877 }
 878 static inline void unregister_ftrace_graph(void) { }
 879
 880 static inline int task_curr_ret_stack(struct task_struct *tsk)
 881 {
 882         return -1;
 883 }
 884
 885 static inline unsigned long
 886 ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret,
 887                       unsigned long *retp)
 888 {
 889         return ret;
 890 }
 891
 892 static inline void pause_graph_tracing(void) { }
 893 static inline void unpause_graph_tracing(void) { }
 894 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 895
 896 #ifdef CONFIG_TRACING
 897
 898 /* flags for current->trace */
 899 enum {
 900         TSK_TRACE_FL_TRACE_BIT  = 0,
 901         TSK_TRACE_FL_GRAPH_BIT  = 1,
 902 };
 903 enum {
 904         TSK_TRACE_FL_TRACE      = 1 << TSK_TRACE_FL_TRACE_BIT,
 905         TSK_TRACE_FL_GRAPH      = 1 << TSK_TRACE_FL_GRAPH_BIT,
 906 };
 907
 908 static inline void set_tsk_trace_trace(struct task_struct *tsk)
 909 {
 910         set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 911 }
 912
 913 static inline void clear_tsk_trace_trace(struct task_struct *tsk)
 914 {
 915         clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 916 }
 917
 918 static inline int test_tsk_trace_trace(struct task_struct *tsk)
 919 {
 920         return tsk->trace & TSK_TRACE_FL_TRACE;
 921 }
 922
 923 static inline void set_tsk_trace_graph(struct task_struct *tsk)
 924 {
 925         set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 926 }
 927
 928 static inline void clear_tsk_trace_graph(struct task_struct *tsk)
 929 {
 930         clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 931 }
 932
 933 static inline int test_tsk_trace_graph(struct task_struct *tsk)
 934 {
 935         return tsk->trace & TSK_TRACE_FL_GRAPH;
 936 }
 937
 938 enum ftrace_dump_mode;
 939
 940 extern enum ftrace_dump_mode ftrace_dump_on_oops;
 941 extern int tracepoint_printk;
 942
 943 extern void disable_trace_on_warning(void);
 944 extern int __disable_trace_on_warning;
 945
 946 #ifdef CONFIG_PREEMPT
 947 #define INIT_TRACE_RECURSION            .trace_recursion = 0,
 948 #endif
 949
 950 int tracepoint_printk_sysctl(struct ctl_table *table, int write,
 951                              void __user *buffer, size_t *lenp,
 952                              loff_t *ppos);
 953
 954 #else /* CONFIG_TRACING */
 955 static inline void  disable_trace_on_warning(void) { }
 956 #endif /* CONFIG_TRACING */
 957
 958 #ifndef INIT_TRACE_RECURSION
 959 #define INIT_TRACE_RECURSION
 960 #endif
 961
 962 #ifdef CONFIG_FTRACE_SYSCALLS
 963
 964 unsigned long arch_syscall_addr(int nr);
 965
 966 #endif /* CONFIG_FTRACE_SYSCALLS */
 967
 968 #endif /* _LINUX_FTRACE_H */