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         int                             nr_trampolines;
 169         struct ftrace_ops_hash          local_hash;
 170         struct ftrace_ops_hash          *func_hash;
 171         struct ftrace_ops_hash          old_hash;
 172         unsigned long                   trampoline;
 173         unsigned long                   trampoline_size;
 174 #endif
 175 };
 176
 177 /*
 178  * Type of the current tracing.
 179  */
 180 enum ftrace_tracing_type_t {
 181         FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
 182         FTRACE_TYPE_RETURN,     /* Hook the return of the function */
 183 };
 184
 185 /* Current tracing type, default is FTRACE_TYPE_ENTER */
 186 extern enum ftrace_tracing_type_t ftrace_tracing_type;
 187
 188 /*
 189  * The ftrace_ops must be a static and should also
 190  * be read_mostly.  These functions do modify read_mostly variables
 191  * so use them sparely. Never free an ftrace_op or modify the
 192  * next pointer after it has been registered. Even after unregistering
 193  * it, the next pointer may still be used internally.
 194  */
 195 int register_ftrace_function(struct ftrace_ops *ops);
 196 int unregister_ftrace_function(struct ftrace_ops *ops);
 197 void clear_ftrace_function(void);
 198
 199 /**
 200  * ftrace_function_local_enable - enable ftrace_ops on current cpu
 201  *
 202  * This function enables tracing on current cpu by decreasing
 203  * the per cpu control variable.
 204  * It must be called with preemption disabled and only on ftrace_ops
 205  * registered with FTRACE_OPS_FL_PER_CPU. If called without preemption
 206  * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
 207  */
 208 static inline void ftrace_function_local_enable(struct ftrace_ops *ops)
 209 {
 210         if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU)))
 211                 return;
 212
 213         (*this_cpu_ptr(ops->disabled))--;
 214 }
 215
 216 /**
 217  * ftrace_function_local_disable - disable ftrace_ops on current cpu
 218  *
 219  * This function disables tracing on current cpu by increasing
 220  * the per cpu control variable.
 221  * It must be called with preemption disabled and only on ftrace_ops
 222  * registered with FTRACE_OPS_FL_PER_CPU. If called without preemption
 223  * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
 224  */
 225 static inline void ftrace_function_local_disable(struct ftrace_ops *ops)
 226 {
 227         if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU)))
 228                 return;
 229
 230         (*this_cpu_ptr(ops->disabled))++;
 231 }
 232
 233 /**
 234  * ftrace_function_local_disabled - returns ftrace_ops disabled value
 235  *                                  on current cpu
 236  *
 237  * This function returns value of ftrace_ops::disabled on current cpu.
 238  * It must be called with preemption disabled and only on ftrace_ops
 239  * registered with FTRACE_OPS_FL_PER_CPU. If called without preemption
 240  * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
 241  */
 242 static inline int ftrace_function_local_disabled(struct ftrace_ops *ops)
 243 {
 244         WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU));
 245         return *this_cpu_ptr(ops->disabled);
 246 }
 247
 248 extern void ftrace_stub(unsigned long a0, unsigned long a1,
 249                         struct ftrace_ops *op, struct pt_regs *regs);
 250
 251 #else /* !CONFIG_FUNCTION_TRACER */
 252 /*
 253  * (un)register_ftrace_function must be a macro since the ops parameter
 254  * must not be evaluated.
 255  */
 256 #define register_ftrace_function(ops) ({ 0; })
 257 #define unregister_ftrace_function(ops) ({ 0; })
 258 static inline int ftrace_nr_registered_ops(void)
 259 {
 260         return 0;
 261 }
 262 static inline void clear_ftrace_function(void) { }
 263 static inline void ftrace_kill(void) { }
 264 #endif /* CONFIG_FUNCTION_TRACER */
 265
 266 #ifdef CONFIG_STACK_TRACER
 267
 268 #define STACK_TRACE_ENTRIES 500
 269
 270 struct stack_trace;
 271
 272 extern unsigned stack_trace_index[];
 273 extern struct stack_trace stack_trace_max;
 274 extern unsigned long stack_trace_max_size;
 275 extern arch_spinlock_t stack_trace_max_lock;
 276
 277 extern int stack_tracer_enabled;
 278 void stack_trace_print(void);
 279 int
 280 stack_trace_sysctl(struct ctl_table *table, int write,
 281                    void __user *buffer, size_t *lenp,
 282                    loff_t *ppos);
 283 #endif
 284
 285 struct ftrace_func_command {
 286         struct list_head        list;
 287         char                    *name;
 288         int                     (*func)(struct ftrace_hash *hash,
 289                                         char *func, char *cmd,
 290                                         char *params, int enable);
 291 };
 292
 293 #ifdef CONFIG_DYNAMIC_FTRACE
 294
 295 int ftrace_arch_code_modify_prepare(void);
 296 int ftrace_arch_code_modify_post_process(void);
 297
 298 struct dyn_ftrace;
 299
 300 enum ftrace_bug_type {
 301         FTRACE_BUG_UNKNOWN,
 302         FTRACE_BUG_INIT,
 303         FTRACE_BUG_NOP,
 304         FTRACE_BUG_CALL,
 305         FTRACE_BUG_UPDATE,
 306 };
 307 extern enum ftrace_bug_type ftrace_bug_type;
 308
 309 /*
 310  * Archs can set this to point to a variable that holds the value that was
 311  * expected at the call site before calling ftrace_bug().
 312  */
 313 extern const void *ftrace_expected;
 314
 315 void ftrace_bug(int err, struct dyn_ftrace *rec);
 316
 317 struct seq_file;
 318
 319 struct ftrace_probe_ops {
 320         void                    (*func)(unsigned long ip,
 321                                         unsigned long parent_ip,
 322                                         void **data);
 323         int                     (*init)(struct ftrace_probe_ops *ops,
 324                                         unsigned long ip, void **data);
 325         void                    (*free)(struct ftrace_probe_ops *ops,
 326                                         unsigned long ip, void **data);
 327         int                     (*print)(struct seq_file *m,
 328                                          unsigned long ip,
 329                                          struct ftrace_probe_ops *ops,
 330                                          void *data);
 331 };
 332
 333 extern int
 334 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 335                               void *data);
 336 extern void
 337 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 338                                 void *data);
 339 extern void
 340 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops);
 341 extern void unregister_ftrace_function_probe_all(char *glob);
 342
 343 extern int ftrace_text_reserved(const void *start, const void *end);
 344
 345 extern int ftrace_nr_registered_ops(void);
 346
 347 bool is_ftrace_trampoline(unsigned long addr);
 348
 349 /*
 350  * The dyn_ftrace record's flags field is split into two parts.
 351  * the first part which is '0-FTRACE_REF_MAX' is a counter of
 352  * the number of callbacks that have registered the function that
 353  * the dyn_ftrace descriptor represents.
 354  *
 355  * The second part is a mask:
 356  *  ENABLED - the function is being traced
 357  *  REGS    - the record wants the function to save regs
 358  *  REGS_EN - the function is set up to save regs.
 359  *  IPMODIFY - the record allows for the IP address to be changed.
 360  *  DISABLED - the record is not ready to be touched yet
 361  *
 362  * When a new ftrace_ops is registered and wants a function to save
 363  * pt_regs, the rec->flag REGS is set. When the function has been
 364  * set up to save regs, the REG_EN flag is set. Once a function
 365  * starts saving regs it will do so until all ftrace_ops are removed
 366  * from tracing that function.
 367  */
 368 enum {
 369         FTRACE_FL_ENABLED       = (1UL << 31),
 370         FTRACE_FL_REGS          = (1UL << 30),
 371         FTRACE_FL_REGS_EN       = (1UL << 29),
 372         FTRACE_FL_TRAMP         = (1UL << 28),
 373         FTRACE_FL_TRAMP_EN      = (1UL << 27),
 374         FTRACE_FL_IPMODIFY      = (1UL << 26),
 375         FTRACE_FL_DISABLED      = (1UL << 25),
 376 };
 377
 378 #define FTRACE_REF_MAX_SHIFT    25
 379 #define FTRACE_FL_BITS          7
 380 #define FTRACE_FL_MASKED_BITS   ((1UL << FTRACE_FL_BITS) - 1)
 381 #define FTRACE_FL_MASK          (FTRACE_FL_MASKED_BITS << FTRACE_REF_MAX_SHIFT)
 382 #define FTRACE_REF_MAX          ((1UL << FTRACE_REF_MAX_SHIFT) - 1)
 383
 384 #define ftrace_rec_count(rec)   ((rec)->flags & ~FTRACE_FL_MASK)
 385
 386 struct dyn_ftrace {
 387         unsigned long           ip; /* address of mcount call-site */
 388         unsigned long           flags;
 389         struct dyn_arch_ftrace  arch;
 390 };
 391
 392 int ftrace_force_update(void);
 393 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
 394                          int remove, int reset);
 395 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
 396                        int len, int reset);
 397 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
 398                         int len, int reset);
 399 void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
 400 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
 401 void ftrace_free_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_get_addr_new(struct dyn_ftrace *rec);
 460 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec);
 461
 462 extern ftrace_func_t ftrace_trace_function;
 463
 464 int ftrace_regex_open(struct ftrace_ops *ops, int flag,
 465                   struct inode *inode, struct file *file);
 466 ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 467                             size_t cnt, loff_t *ppos);
 468 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 469                              size_t cnt, loff_t *ppos);
 470 int ftrace_regex_release(struct inode *inode, struct file *file);
 471
 472 void __init
 473 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
 474
 475 /* defined in arch */
 476 extern int ftrace_ip_converted(unsigned long ip);
 477 extern int ftrace_dyn_arch_init(void);
 478 extern void ftrace_replace_code(int enable);
 479 extern int ftrace_update_ftrace_func(ftrace_func_t func);
 480 extern void ftrace_caller(void);
 481 extern void ftrace_regs_caller(void);
 482 extern void ftrace_call(void);
 483 extern void ftrace_regs_call(void);
 484 extern void mcount_call(void);
 485
 486 void ftrace_modify_all_code(int command);
 487
 488 #ifndef FTRACE_ADDR
 489 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
 490 #endif
 491
 492 #ifndef FTRACE_GRAPH_ADDR
 493 #define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller)
 494 #endif
 495
 496 #ifndef FTRACE_REGS_ADDR
 497 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 498 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller)
 499 #else
 500 # define FTRACE_REGS_ADDR FTRACE_ADDR
 501 #endif
 502 #endif
 503
 504 /*
 505  * If an arch would like functions that are only traced
 506  * by the function graph tracer to jump directly to its own
 507  * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR
 508  * to be that address to jump to.
 509  */
 510 #ifndef FTRACE_GRAPH_TRAMP_ADDR
 511 #define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0)
 512 #endif
 513
 514 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 515 extern void ftrace_graph_caller(void);
 516 extern int ftrace_enable_ftrace_graph_caller(void);
 517 extern int ftrace_disable_ftrace_graph_caller(void);
 518 #else
 519 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
 520 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
 521 #endif
 522
 523 /**
 524  * ftrace_make_nop - convert code into nop
 525  * @mod: module structure if called by module load initialization
 526  * @rec: the mcount call site record
 527  * @addr: the address that the call site should be calling
 528  *
 529  * This is a very sensitive operation and great care needs
 530  * to be taken by the arch.  The operation should carefully
 531  * read the location, check to see if what is read is indeed
 532  * what we expect it to be, and then on success of the compare,
 533  * it should write to the location.
 534  *
 535  * The code segment at @rec->ip should be a caller to @addr
 536  *
 537  * Return must be:
 538  *  0 on success
 539  *  -EFAULT on error reading the location
 540  *  -EINVAL on a failed compare of the contents
 541  *  -EPERM  on error writing to the location
 542  * Any other value will be considered a failure.
 543  */
 544 extern int ftrace_make_nop(struct module *mod,
 545                            struct dyn_ftrace *rec, unsigned long addr);
 546
 547 /**
 548  * ftrace_make_call - convert a nop call site into a call to addr
 549  * @rec: the mcount call site record
 550  * @addr: the address that the call site should call
 551  *
 552  * This is a very sensitive operation and great care needs
 553  * to be taken by the arch.  The operation should carefully
 554  * read the location, check to see if what is read is indeed
 555  * what we expect it to be, and then on success of the compare,
 556  * it should write to the location.
 557  *
 558  * The code segment at @rec->ip should be a nop
 559  *
 560  * Return must be:
 561  *  0 on success
 562  *  -EFAULT on error reading the location
 563  *  -EINVAL on a failed compare of the contents
 564  *  -EPERM  on error writing to the location
 565  * Any other value will be considered a failure.
 566  */
 567 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
 568
 569 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 570 /**
 571  * ftrace_modify_call - convert from one addr to another (no nop)
 572  * @rec: the mcount call site record
 573  * @old_addr: the address expected to be currently called to
 574  * @addr: the address to change to
 575  *
 576  * This is a very sensitive operation and great care needs
 577  * to be taken by the arch.  The operation should carefully
 578  * read the location, check to see if what is read is indeed
 579  * what we expect it to be, and then on success of the compare,
 580  * it should write to the location.
 581  *
 582  * The code segment at @rec->ip should be a caller to @old_addr
 583  *
 584  * Return must be:
 585  *  0 on success
 586  *  -EFAULT on error reading the location
 587  *  -EINVAL on a failed compare of the contents
 588  *  -EPERM  on error writing to the location
 589  * Any other value will be considered a failure.
 590  */
 591 extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 592                               unsigned long addr);
 593 #else
 594 /* Should never be called */
 595 static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 596                                      unsigned long addr)
 597 {
 598         return -EINVAL;
 599 }
 600 #endif
 601
 602 /* May be defined in arch */
 603 extern int ftrace_arch_read_dyn_info(char *buf, int size);
 604
 605 extern int skip_trace(unsigned long ip);
 606 extern void ftrace_module_init(struct module *mod);
 607 extern void ftrace_release_mod(struct module *mod);
 608
 609 extern void ftrace_disable_daemon(void);
 610 extern void ftrace_enable_daemon(void);
 611 #else /* CONFIG_DYNAMIC_FTRACE */
 612 static inline int skip_trace(unsigned long ip) { return 0; }
 613 static inline int ftrace_force_update(void) { return 0; }
 614 static inline void ftrace_disable_daemon(void) { }
 615 static inline void ftrace_enable_daemon(void) { }
 616 static inline void ftrace_release_mod(struct module *mod) {}
 617 static inline void ftrace_module_init(struct module *mod) {}
 618 static inline __init int register_ftrace_command(struct ftrace_func_command *cmd)
 619 {
 620         return -EINVAL;
 621 }
 622 static inline __init int unregister_ftrace_command(char *cmd_name)
 623 {
 624         return -EINVAL;
 625 }
 626 static inline int ftrace_text_reserved(const void *start, const void *end)
 627 {
 628         return 0;
 629 }
 630 static inline unsigned long ftrace_location(unsigned long ip)
 631 {
 632         return 0;
 633 }
 634
 635 /*
 636  * Again users of functions that have ftrace_ops may not
 637  * have them defined when ftrace is not enabled, but these
 638  * functions may still be called. Use a macro instead of inline.
 639  */
 640 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
 641 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
 642 #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; })
 643 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
 644 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
 645 #define ftrace_free_filter(ops) do { } while (0)
 646
 647 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 648                             size_t cnt, loff_t *ppos) { return -ENODEV; }
 649 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 650                              size_t cnt, loff_t *ppos) { return -ENODEV; }
 651 static inline int
 652 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
 653
 654 static inline bool is_ftrace_trampoline(unsigned long addr)
 655 {
 656         return false;
 657 }
 658 #endif /* CONFIG_DYNAMIC_FTRACE */
 659
 660 /* totally disable ftrace - can not re-enable after this */
 661 void ftrace_kill(void);
 662
 663 static inline void tracer_disable(void)
 664 {
 665 #ifdef CONFIG_FUNCTION_TRACER
 666         ftrace_enabled = 0;
 667 #endif
 668 }
 669
 670 /*
 671  * Ftrace disable/restore without lock. Some synchronization mechanism
 672  * must be used to prevent ftrace_enabled to be changed between
 673  * disable/restore.
 674  */
 675 static inline int __ftrace_enabled_save(void)
 676 {
 677 #ifdef CONFIG_FUNCTION_TRACER
 678         int saved_ftrace_enabled = ftrace_enabled;
 679         ftrace_enabled = 0;
 680         return saved_ftrace_enabled;
 681 #else
 682         return 0;
 683 #endif
 684 }
 685
 686 static inline void __ftrace_enabled_restore(int enabled)
 687 {
 688 #ifdef CONFIG_FUNCTION_TRACER
 689         ftrace_enabled = enabled;
 690 #endif
 691 }
 692
 693 /* All archs should have this, but we define it for consistency */
 694 #ifndef ftrace_return_address0
 695 # define ftrace_return_address0 __builtin_return_address(0)
 696 #endif
 697
 698 /* Archs may use other ways for ADDR1 and beyond */
 699 #ifndef ftrace_return_address
 700 # ifdef CONFIG_FRAME_POINTER
 701 #  define ftrace_return_address(n) __builtin_return_address(n)
 702 # else
 703 #  define ftrace_return_address(n) 0UL
 704 # endif
 705 #endif
 706
 707 #define CALLER_ADDR0 ((unsigned long)ftrace_return_address0)
 708 #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1))
 709 #define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2))
 710 #define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3))
 711 #define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4))
 712 #define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5))
 713 #define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6))
 714
 715 #ifdef CONFIG_IRQSOFF_TRACER
 716   extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
 717   extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
 718 #else
 719   static inline void time_hardirqs_on(unsigned long a0, unsigned long a1) { }
 720   static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { }
 721 #endif
 722
 723 #ifdef CONFIG_PREEMPT_TRACER
 724   extern void trace_preempt_on(unsigned long a0, unsigned long a1);
 725   extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 726 #else
 727 /*
 728  * Use defines instead of static inlines because some arches will make code out
 729  * of the CALLER_ADDR, when we really want these to be a real nop.
 730  */
 731 # define trace_preempt_on(a0, a1) do { } while (0)
 732 # define trace_preempt_off(a0, a1) do { } while (0)
 733 #endif
 734
 735 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 736 extern void ftrace_init(void);
 737 #else
 738 static inline void ftrace_init(void) { }
 739 #endif
 740
 741 /*
 742  * Structure that defines an entry function trace.
 743  */
 744 struct ftrace_graph_ent {
 745         unsigned long func; /* Current function */
 746         int depth;
 747 };
 748
 749 /*
 750  * Structure that defines a return function trace.
 751  */
 752 struct ftrace_graph_ret {
 753         unsigned long func; /* Current function */
 754         unsigned long long calltime;
 755         unsigned long long rettime;
 756         /* Number of functions that overran the depth limit for current task */
 757         unsigned long overrun;
 758         int depth;
 759 };
 760
 761 /* Type of the callback handlers for tracing function graph*/
 762 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
 763 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
 764
 765 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 766
 767 /* for init task */
 768 #define INIT_FTRACE_GRAPH               .ret_stack = NULL,
 769
 770 /*
 771  * Stack of return addresses for functions
 772  * of a thread.
 773  * Used in struct thread_info
 774  */
 775 struct ftrace_ret_stack {
 776         unsigned long ret;
 777         unsigned long func;
 778         unsigned long long calltime;
 779         unsigned long long subtime;
 780         unsigned long fp;
 781 };
 782
 783 /*
 784  * Primary handler of a function return.
 785  * It relays on ftrace_return_to_handler.
 786  * Defined in entry_32/64.S
 787  */
 788 extern void return_to_handler(void);
 789
 790 extern int
 791 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
 792                          unsigned long frame_pointer);
 793
 794 /*
 795  * Sometimes we don't want to trace a function with the function
 796  * graph tracer but we want them to keep traced by the usual function
 797  * tracer if the function graph tracer is not configured.
 798  */
 799 #define __notrace_funcgraph             notrace
 800
 801 /*
 802  * We want to which function is an entrypoint of a hardirq.
 803  * That will help us to put a signal on output.
 804  */
 805 #define __irq_entry              __attribute__((__section__(".irqentry.text")))
 806
 807 /* Limits of hardirq entrypoints */
 808 extern char __irqentry_text_start[];
 809 extern char __irqentry_text_end[];
 810
 811 #define FTRACE_NOTRACE_DEPTH 65536
 812 #define FTRACE_RETFUNC_DEPTH 50
 813 #define FTRACE_RETSTACK_ALLOC_SIZE 32
 814 extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 815                                 trace_func_graph_ent_t entryfunc);
 816
 817 extern bool ftrace_graph_is_dead(void);
 818 extern void ftrace_graph_stop(void);
 819
 820 /* The current handlers in use */
 821 extern trace_func_graph_ret_t ftrace_graph_return;
 822 extern trace_func_graph_ent_t ftrace_graph_entry;
 823
 824 extern void unregister_ftrace_graph(void);
 825
 826 extern void ftrace_graph_init_task(struct task_struct *t);
 827 extern void ftrace_graph_exit_task(struct task_struct *t);
 828 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
 829
 830 static inline int task_curr_ret_stack(struct task_struct *t)
 831 {
 832         return t->curr_ret_stack;
 833 }
 834
 835 static inline void pause_graph_tracing(void)
 836 {
 837         atomic_inc(&current->tracing_graph_pause);
 838 }
 839
 840 static inline void unpause_graph_tracing(void)
 841 {
 842         atomic_dec(&current->tracing_graph_pause);
 843 }
 844 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */
 845
 846 #define __notrace_funcgraph
 847 #define __irq_entry
 848 #define INIT_FTRACE_GRAPH
 849
 850 static inline void ftrace_graph_init_task(struct task_struct *t) { }
 851 static inline void ftrace_graph_exit_task(struct task_struct *t) { }
 852 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
 853
 854 static inline int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 855                           trace_func_graph_ent_t entryfunc)
 856 {
 857         return -1;
 858 }
 859 static inline void unregister_ftrace_graph(void) { }
 860
 861 static inline int task_curr_ret_stack(struct task_struct *tsk)
 862 {
 863         return -1;
 864 }
 865
 866 static inline void pause_graph_tracing(void) { }
 867 static inline void unpause_graph_tracing(void) { }
 868 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 869
 870 #ifdef CONFIG_TRACING
 871
 872 /* flags for current->trace */
 873 enum {
 874         TSK_TRACE_FL_TRACE_BIT  = 0,
 875         TSK_TRACE_FL_GRAPH_BIT  = 1,
 876 };
 877 enum {
 878         TSK_TRACE_FL_TRACE      = 1 << TSK_TRACE_FL_TRACE_BIT,
 879         TSK_TRACE_FL_GRAPH      = 1 << TSK_TRACE_FL_GRAPH_BIT,
 880 };
 881
 882 static inline void set_tsk_trace_trace(struct task_struct *tsk)
 883 {
 884         set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 885 }
 886
 887 static inline void clear_tsk_trace_trace(struct task_struct *tsk)
 888 {
 889         clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 890 }
 891
 892 static inline int test_tsk_trace_trace(struct task_struct *tsk)
 893 {
 894         return tsk->trace & TSK_TRACE_FL_TRACE;
 895 }
 896
 897 static inline void set_tsk_trace_graph(struct task_struct *tsk)
 898 {
 899         set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 900 }
 901
 902 static inline void clear_tsk_trace_graph(struct task_struct *tsk)
 903 {
 904         clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 905 }
 906
 907 static inline int test_tsk_trace_graph(struct task_struct *tsk)
 908 {
 909         return tsk->trace & TSK_TRACE_FL_GRAPH;
 910 }
 911
 912 enum ftrace_dump_mode;
 913
 914 extern enum ftrace_dump_mode ftrace_dump_on_oops;
 915 extern int tracepoint_printk;
 916
 917 extern void disable_trace_on_warning(void);
 918 extern int __disable_trace_on_warning;
 919
 920 #ifdef CONFIG_PREEMPT
 921 #define INIT_TRACE_RECURSION            .trace_recursion = 0,
 922 #endif
 923
 924 #else /* CONFIG_TRACING */
 925 static inline void  disable_trace_on_warning(void) { }
 926 #endif /* CONFIG_TRACING */
 927
 928 #ifndef INIT_TRACE_RECURSION
 929 #define INIT_TRACE_RECURSION
 930 #endif
 931
 932 #ifdef CONFIG_FTRACE_SYSCALLS
 933
 934 unsigned long arch_syscall_addr(int nr);
 935
 936 #endif /* CONFIG_FTRACE_SYSCALLS */
 937
 938 #endif /* _LINUX_FTRACE_H */