linux/include/linux/ftrace.h
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   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
  44void trace_init(void);
  45#else
  46static inline void trace_init(void) { }
  47#endif
  48
  49struct module;
  50struct ftrace_hash;
  51
  52#ifdef CONFIG_FUNCTION_TRACER
  53
  54extern int ftrace_enabled;
  55extern int
  56ftrace_enable_sysctl(struct ctl_table *table, int write,
  57                     void __user *buffer, size_t *lenp,
  58                     loff_t *ppos);
  59
  60struct ftrace_ops;
  61
  62typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
  63                              struct ftrace_ops *op, struct pt_regs *regs);
  64
  65ftrace_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 */
 121enum {
 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 */
 142struct 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 */
 160struct 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 */
 179enum 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 */
 185extern 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 */
 194int register_ftrace_function(struct ftrace_ops *ops);
 195int unregister_ftrace_function(struct ftrace_ops *ops);
 196void 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 */
 207static 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 */
 224static 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 */
 241static 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
 247extern 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; })
 257static inline int ftrace_nr_registered_ops(void)
 258{
 259        return 0;
 260}
 261static inline void clear_ftrace_function(void) { }
 262static inline void ftrace_kill(void) { }
 263#endif /* CONFIG_FUNCTION_TRACER */
 264
 265#ifdef CONFIG_STACK_TRACER
 266
 267#define STACK_TRACE_ENTRIES 500
 268
 269struct stack_trace;
 270
 271extern unsigned stack_trace_index[];
 272extern struct stack_trace stack_trace_max;
 273extern unsigned long stack_trace_max_size;
 274extern arch_spinlock_t stack_trace_max_lock;
 275
 276extern int stack_tracer_enabled;
 277void stack_trace_print(void);
 278int
 279stack_trace_sysctl(struct ctl_table *table, int write,
 280                   void __user *buffer, size_t *lenp,
 281                   loff_t *ppos);
 282#endif
 283
 284struct 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
 294int ftrace_arch_code_modify_prepare(void);
 295int ftrace_arch_code_modify_post_process(void);
 296
 297struct dyn_ftrace;
 298
 299enum ftrace_bug_type {
 300        FTRACE_BUG_UNKNOWN,
 301        FTRACE_BUG_INIT,
 302        FTRACE_BUG_NOP,
 303        FTRACE_BUG_CALL,
 304        FTRACE_BUG_UPDATE,
 305};
 306extern 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 */
 312extern const void *ftrace_expected;
 313
 314void ftrace_bug(int err, struct dyn_ftrace *rec);
 315
 316struct seq_file;
 317
 318struct 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
 332extern int
 333register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 334                              void *data);
 335extern void
 336unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 337                                void *data);
 338extern void
 339unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops);
 340extern void unregister_ftrace_function_probe_all(char *glob);
 341
 342extern int ftrace_text_reserved(const void *start, const void *end);
 343
 344extern int ftrace_nr_registered_ops(void);
 345
 346bool 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 */
 367enum {
 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
 385struct dyn_ftrace {
 386        unsigned long           ip; /* address of mcount call-site */
 387        unsigned long           flags;
 388        struct dyn_arch_ftrace  arch;
 389};
 390
 391int ftrace_force_update(void);
 392int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
 393                         int remove, int reset);
 394int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
 395                       int len, int reset);
 396int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
 397                        int len, int reset);
 398void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
 399void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
 400void ftrace_free_filter(struct ftrace_ops *ops);
 401
 402int register_ftrace_command(struct ftrace_func_command *cmd);
 403int unregister_ftrace_command(struct ftrace_func_command *cmd);
 404
 405enum {
 406        FTRACE_UPDATE_CALLS             = (1 << 0),
 407        FTRACE_DISABLE_CALLS            = (1 << 1),
 408        FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
 409        FTRACE_START_FUNC_RET           = (1 << 3),
 410        FTRACE_STOP_FUNC_RET            = (1 << 4),
 411};
 412
 413/*
 414 * The FTRACE_UPDATE_* enum is used to pass information back
 415 * from the ftrace_update_record() and ftrace_test_record()
 416 * functions. These are called by the code update routines
 417 * to find out what is to be done for a given function.
 418 *
 419 *  IGNORE           - The function is already what we want it to be
 420 *  MAKE_CALL        - Start tracing the function
 421 *  MODIFY_CALL      - Stop saving regs for the function
 422 *  MAKE_NOP         - Stop tracing the function
 423 */
 424enum {
 425        FTRACE_UPDATE_IGNORE,
 426        FTRACE_UPDATE_MAKE_CALL,
 427        FTRACE_UPDATE_MODIFY_CALL,
 428        FTRACE_UPDATE_MAKE_NOP,
 429};
 430
 431enum {
 432        FTRACE_ITER_FILTER      = (1 << 0),
 433        FTRACE_ITER_NOTRACE     = (1 << 1),
 434        FTRACE_ITER_PRINTALL    = (1 << 2),
 435        FTRACE_ITER_DO_HASH     = (1 << 3),
 436        FTRACE_ITER_HASH        = (1 << 4),
 437        FTRACE_ITER_ENABLED     = (1 << 5),
 438};
 439
 440void arch_ftrace_update_code(int command);
 441
 442struct ftrace_rec_iter;
 443
 444struct ftrace_rec_iter *ftrace_rec_iter_start(void);
 445struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
 446struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);
 447
 448#define for_ftrace_rec_iter(iter)               \
 449        for (iter = ftrace_rec_iter_start();    \
 450             iter;                              \
 451             iter = ftrace_rec_iter_next(iter))
 452
 453
 454int ftrace_update_record(struct dyn_ftrace *rec, int enable);
 455int ftrace_test_record(struct dyn_ftrace *rec, int enable);
 456void ftrace_run_stop_machine(int command);
 457unsigned long ftrace_location(unsigned long ip);
 458unsigned long ftrace_location_range(unsigned long start, unsigned long end);
 459unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec);
 460unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec);
 461
 462extern ftrace_func_t ftrace_trace_function;
 463
 464int ftrace_regex_open(struct ftrace_ops *ops, int flag,
 465                  struct inode *inode, struct file *file);
 466ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 467                            size_t cnt, loff_t *ppos);
 468ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 469                             size_t cnt, loff_t *ppos);
 470int ftrace_regex_release(struct inode *inode, struct file *file);
 471
 472void __init
 473ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
 474
 475/* defined in arch */
 476extern int ftrace_ip_converted(unsigned long ip);
 477extern int ftrace_dyn_arch_init(void);
 478extern void ftrace_replace_code(int enable);
 479extern int ftrace_update_ftrace_func(ftrace_func_t func);
 480extern void ftrace_caller(void);
 481extern void ftrace_regs_caller(void);
 482extern void ftrace_call(void);
 483extern void ftrace_regs_call(void);
 484extern void mcount_call(void);
 485
 486void 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
 515extern void ftrace_graph_caller(void);
 516extern int ftrace_enable_ftrace_graph_caller(void);
 517extern int ftrace_disable_ftrace_graph_caller(void);
 518#else
 519static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
 520static 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 */
 544extern 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 */
 567extern 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 */
 591extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 592                              unsigned long addr);
 593#else
 594/* Should never be called */
 595static 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 */
 603extern int ftrace_arch_read_dyn_info(char *buf, int size);
 604
 605extern int skip_trace(unsigned long ip);
 606extern void ftrace_module_init(struct module *mod);
 607extern void ftrace_module_enable(struct module *mod);
 608extern void ftrace_release_mod(struct module *mod);
 609
 610extern void ftrace_disable_daemon(void);
 611extern void ftrace_enable_daemon(void);
 612#else /* CONFIG_DYNAMIC_FTRACE */
 613static inline int skip_trace(unsigned long ip) { return 0; }
 614static inline int ftrace_force_update(void) { return 0; }
 615static inline void ftrace_disable_daemon(void) { }
 616static inline void ftrace_enable_daemon(void) { }
 617static inline void ftrace_module_init(struct module *mod) { }
 618static inline void ftrace_module_enable(struct module *mod) { }
 619static inline void ftrace_release_mod(struct module *mod) { }
 620static inline __init int register_ftrace_command(struct ftrace_func_command *cmd)
 621{
 622        return -EINVAL;
 623}
 624static inline __init int unregister_ftrace_command(char *cmd_name)
 625{
 626        return -EINVAL;
 627}
 628static inline int ftrace_text_reserved(const void *start, const void *end)
 629{
 630        return 0;
 631}
 632static inline unsigned long ftrace_location(unsigned long ip)
 633{
 634        return 0;
 635}
 636
 637/*
 638 * Again users of functions that have ftrace_ops may not
 639 * have them defined when ftrace is not enabled, but these
 640 * functions may still be called. Use a macro instead of inline.
 641 */
 642#define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
 643#define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
 644#define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; })
 645#define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
 646#define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
 647#define ftrace_free_filter(ops) do { } while (0)
 648
 649static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 650                            size_t cnt, loff_t *ppos) { return -ENODEV; }
 651static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 652                             size_t cnt, loff_t *ppos) { return -ENODEV; }
 653static inline int
 654ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
 655
 656static inline bool is_ftrace_trampoline(unsigned long addr)
 657{
 658        return false;
 659}
 660#endif /* CONFIG_DYNAMIC_FTRACE */
 661
 662/* totally disable ftrace - can not re-enable after this */
 663void ftrace_kill(void);
 664
 665static inline void tracer_disable(void)
 666{
 667#ifdef CONFIG_FUNCTION_TRACER
 668        ftrace_enabled = 0;
 669#endif
 670}
 671
 672/*
 673 * Ftrace disable/restore without lock. Some synchronization mechanism
 674 * must be used to prevent ftrace_enabled to be changed between
 675 * disable/restore.
 676 */
 677static inline int __ftrace_enabled_save(void)
 678{
 679#ifdef CONFIG_FUNCTION_TRACER
 680        int saved_ftrace_enabled = ftrace_enabled;
 681        ftrace_enabled = 0;
 682        return saved_ftrace_enabled;
 683#else
 684        return 0;
 685#endif
 686}
 687
 688static inline void __ftrace_enabled_restore(int enabled)
 689{
 690#ifdef CONFIG_FUNCTION_TRACER
 691        ftrace_enabled = enabled;
 692#endif
 693}
 694
 695/* All archs should have this, but we define it for consistency */
 696#ifndef ftrace_return_address0
 697# define ftrace_return_address0 __builtin_return_address(0)
 698#endif
 699
 700/* Archs may use other ways for ADDR1 and beyond */
 701#ifndef ftrace_return_address
 702# ifdef CONFIG_FRAME_POINTER
 703#  define ftrace_return_address(n) __builtin_return_address(n)
 704# else
 705#  define ftrace_return_address(n) 0UL
 706# endif
 707#endif
 708
 709#define CALLER_ADDR0 ((unsigned long)ftrace_return_address0)
 710#define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1))
 711#define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2))
 712#define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3))
 713#define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4))
 714#define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5))
 715#define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6))
 716
 717static inline unsigned long get_lock_parent_ip(void)
 718{
 719        unsigned long addr = CALLER_ADDR0;
 720
 721        if (!in_lock_functions(addr))
 722                return addr;
 723        addr = CALLER_ADDR1;
 724        if (!in_lock_functions(addr))
 725                return addr;
 726        return CALLER_ADDR2;
 727}
 728
 729#ifdef CONFIG_IRQSOFF_TRACER
 730  extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
 731  extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
 732#else
 733  static inline void time_hardirqs_on(unsigned long a0, unsigned long a1) { }
 734  static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { }
 735#endif
 736
 737#ifdef CONFIG_PREEMPT_TRACER
 738  extern void trace_preempt_on(unsigned long a0, unsigned long a1);
 739  extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 740#else
 741/*
 742 * Use defines instead of static inlines because some arches will make code out
 743 * of the CALLER_ADDR, when we really want these to be a real nop.
 744 */
 745# define trace_preempt_on(a0, a1) do { } while (0)
 746# define trace_preempt_off(a0, a1) do { } while (0)
 747#endif
 748
 749#ifdef CONFIG_FTRACE_MCOUNT_RECORD
 750extern void ftrace_init(void);
 751#else
 752static inline void ftrace_init(void) { }
 753#endif
 754
 755/*
 756 * Structure that defines an entry function trace.
 757 * It's already packed but the attribute "packed" is needed
 758 * to remove extra padding at the end.
 759 */
 760struct ftrace_graph_ent {
 761        unsigned long func; /* Current function */
 762        int depth;
 763} __packed;
 764
 765/*
 766 * Structure that defines a return function trace.
 767 * It's already packed but the attribute "packed" is needed
 768 * to remove extra padding at the end.
 769 */
 770struct ftrace_graph_ret {
 771        unsigned long func; /* Current function */
 772        /* Number of functions that overran the depth limit for current task */
 773        unsigned long overrun;
 774        unsigned long long calltime;
 775        unsigned long long rettime;
 776        int depth;
 777} __packed;
 778
 779/* Type of the callback handlers for tracing function graph*/
 780typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
 781typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
 782
 783#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 784
 785/* for init task */
 786#define INIT_FTRACE_GRAPH               .ret_stack = NULL,
 787
 788/*
 789 * Stack of return addresses for functions
 790 * of a thread.
 791 * Used in struct thread_info
 792 */
 793struct ftrace_ret_stack {
 794        unsigned long ret;
 795        unsigned long func;
 796        unsigned long long calltime;
 797        unsigned long long subtime;
 798        unsigned long fp;
 799};
 800
 801/*
 802 * Primary handler of a function return.
 803 * It relays on ftrace_return_to_handler.
 804 * Defined in entry_32/64.S
 805 */
 806extern void return_to_handler(void);
 807
 808extern int
 809ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
 810                         unsigned long frame_pointer);
 811
 812/*
 813 * Sometimes we don't want to trace a function with the function
 814 * graph tracer but we want them to keep traced by the usual function
 815 * tracer if the function graph tracer is not configured.
 816 */
 817#define __notrace_funcgraph             notrace
 818
 819#define FTRACE_NOTRACE_DEPTH 65536
 820#define FTRACE_RETFUNC_DEPTH 50
 821#define FTRACE_RETSTACK_ALLOC_SIZE 32
 822extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 823                                trace_func_graph_ent_t entryfunc);
 824
 825extern bool ftrace_graph_is_dead(void);
 826extern void ftrace_graph_stop(void);
 827
 828/* The current handlers in use */
 829extern trace_func_graph_ret_t ftrace_graph_return;
 830extern trace_func_graph_ent_t ftrace_graph_entry;
 831
 832extern void unregister_ftrace_graph(void);
 833
 834extern void ftrace_graph_init_task(struct task_struct *t);
 835extern void ftrace_graph_exit_task(struct task_struct *t);
 836extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
 837
 838static inline int task_curr_ret_stack(struct task_struct *t)
 839{
 840        return t->curr_ret_stack;
 841}
 842
 843static inline void pause_graph_tracing(void)
 844{
 845        atomic_inc(&current->tracing_graph_pause);
 846}
 847
 848static inline void unpause_graph_tracing(void)
 849{
 850        atomic_dec(&current->tracing_graph_pause);
 851}
 852#else /* !CONFIG_FUNCTION_GRAPH_TRACER */
 853
 854#define __notrace_funcgraph
 855#define INIT_FTRACE_GRAPH
 856
 857static inline void ftrace_graph_init_task(struct task_struct *t) { }
 858static inline void ftrace_graph_exit_task(struct task_struct *t) { }
 859static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
 860
 861static inline int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 862                          trace_func_graph_ent_t entryfunc)
 863{
 864        return -1;
 865}
 866static inline void unregister_ftrace_graph(void) { }
 867
 868static inline int task_curr_ret_stack(struct task_struct *tsk)
 869{
 870        return -1;
 871}
 872
 873static inline void pause_graph_tracing(void) { }
 874static inline void unpause_graph_tracing(void) { }
 875#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 876
 877#ifdef CONFIG_TRACING
 878
 879/* flags for current->trace */
 880enum {
 881        TSK_TRACE_FL_TRACE_BIT  = 0,
 882        TSK_TRACE_FL_GRAPH_BIT  = 1,
 883};
 884enum {
 885        TSK_TRACE_FL_TRACE      = 1 << TSK_TRACE_FL_TRACE_BIT,
 886        TSK_TRACE_FL_GRAPH      = 1 << TSK_TRACE_FL_GRAPH_BIT,
 887};
 888
 889static inline void set_tsk_trace_trace(struct task_struct *tsk)
 890{
 891        set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 892}
 893
 894static inline void clear_tsk_trace_trace(struct task_struct *tsk)
 895{
 896        clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 897}
 898
 899static inline int test_tsk_trace_trace(struct task_struct *tsk)
 900{
 901        return tsk->trace & TSK_TRACE_FL_TRACE;
 902}
 903
 904static inline void set_tsk_trace_graph(struct task_struct *tsk)
 905{
 906        set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 907}
 908
 909static inline void clear_tsk_trace_graph(struct task_struct *tsk)
 910{
 911        clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 912}
 913
 914static inline int test_tsk_trace_graph(struct task_struct *tsk)
 915{
 916        return tsk->trace & TSK_TRACE_FL_GRAPH;
 917}
 918
 919enum ftrace_dump_mode;
 920
 921extern enum ftrace_dump_mode ftrace_dump_on_oops;
 922extern int tracepoint_printk;
 923
 924extern void disable_trace_on_warning(void);
 925extern int __disable_trace_on_warning;
 926
 927#ifdef CONFIG_PREEMPT
 928#define INIT_TRACE_RECURSION            .trace_recursion = 0,
 929#endif
 930
 931#else /* CONFIG_TRACING */
 932static inline void  disable_trace_on_warning(void) { }
 933#endif /* CONFIG_TRACING */
 934
 935#ifndef INIT_TRACE_RECURSION
 936#define INIT_TRACE_RECURSION
 937#endif
 938
 939#ifdef CONFIG_FTRACE_SYSCALLS
 940
 941unsigned long arch_syscall_addr(int nr);
 942
 943#endif /* CONFIG_FTRACE_SYSCALLS */
 944
 945#endif /* _LINUX_FTRACE_H */
 946