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 !defined(CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST) || \
  37        !ARCH_SUPPORTS_FTRACE_OPS
  38# define FTRACE_FORCE_LIST_FUNC 1
  39#else
  40# define FTRACE_FORCE_LIST_FUNC 0
  41#endif
  42
  43
  44struct module;
  45struct ftrace_hash;
  46
  47#ifdef CONFIG_FUNCTION_TRACER
  48
  49extern int ftrace_enabled;
  50extern int
  51ftrace_enable_sysctl(struct ctl_table *table, int write,
  52                     void __user *buffer, size_t *lenp,
  53                     loff_t *ppos);
  54
  55struct ftrace_ops;
  56
  57typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
  58                              struct ftrace_ops *op, struct pt_regs *regs);
  59
  60/*
  61 * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are
  62 * set in the flags member.
  63 *
  64 * ENABLED - set/unset when ftrace_ops is registered/unregistered
  65 * GLOBAL  - set manualy by ftrace_ops user to denote the ftrace_ops
  66 *           is part of the global tracers sharing the same filter
  67 *           via set_ftrace_* debugfs files.
  68 * DYNAMIC - set when ftrace_ops is registered to denote dynamically
  69 *           allocated ftrace_ops which need special care
  70 * CONTROL - set manualy by ftrace_ops user to denote the ftrace_ops
  71 *           could be controled by following calls:
  72 *             ftrace_function_local_enable
  73 *             ftrace_function_local_disable
  74 * SAVE_REGS - The ftrace_ops wants regs saved at each function called
  75 *            and passed to the callback. If this flag is set, but the
  76 *            architecture does not support passing regs
  77 *            (CONFIG_DYNAMIC_FTRACE_WITH_REGS is not defined), then the
  78 *            ftrace_ops will fail to register, unless the next flag
  79 *            is set.
  80 * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the
  81 *            handler can handle an arch that does not save regs
  82 *            (the handler tests if regs == NULL), then it can set
  83 *            this flag instead. It will not fail registering the ftrace_ops
  84 *            but, the regs field will be NULL if the arch does not support
  85 *            passing regs to the handler.
  86 *            Note, if this flag is set, the SAVE_REGS flag will automatically
  87 *            get set upon registering the ftrace_ops, if the arch supports it.
  88 * RECURSION_SAFE - The ftrace_ops can set this to tell the ftrace infrastructure
  89 *            that the call back has its own recursion protection. If it does
  90 *            not set this, then the ftrace infrastructure will add recursion
  91 *            protection for the caller.
  92 * STUB   - The ftrace_ops is just a place holder.
  93 */
  94enum {
  95        FTRACE_OPS_FL_ENABLED                   = 1 << 0,
  96        FTRACE_OPS_FL_GLOBAL                    = 1 << 1,
  97        FTRACE_OPS_FL_DYNAMIC                   = 1 << 2,
  98        FTRACE_OPS_FL_CONTROL                   = 1 << 3,
  99        FTRACE_OPS_FL_SAVE_REGS                 = 1 << 4,
 100        FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED    = 1 << 5,
 101        FTRACE_OPS_FL_RECURSION_SAFE            = 1 << 6,
 102        FTRACE_OPS_FL_STUB                      = 1 << 7,
 103};
 104
 105struct ftrace_ops {
 106        ftrace_func_t                   func;
 107        struct ftrace_ops               *next;
 108        unsigned long                   flags;
 109        int __percpu                    *disabled;
 110#ifdef CONFIG_DYNAMIC_FTRACE
 111        struct ftrace_hash              *notrace_hash;
 112        struct ftrace_hash              *filter_hash;
 113#endif
 114};
 115
 116extern int function_trace_stop;
 117
 118/*
 119 * Type of the current tracing.
 120 */
 121enum ftrace_tracing_type_t {
 122        FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
 123        FTRACE_TYPE_RETURN,     /* Hook the return of the function */
 124};
 125
 126/* Current tracing type, default is FTRACE_TYPE_ENTER */
 127extern enum ftrace_tracing_type_t ftrace_tracing_type;
 128
 129/**
 130 * ftrace_stop - stop function tracer.
 131 *
 132 * A quick way to stop the function tracer. Note this an on off switch,
 133 * it is not something that is recursive like preempt_disable.
 134 * This does not disable the calling of mcount, it only stops the
 135 * calling of functions from mcount.
 136 */
 137static inline void ftrace_stop(void)
 138{
 139        function_trace_stop = 1;
 140}
 141
 142/**
 143 * ftrace_start - start the function tracer.
 144 *
 145 * This function is the inverse of ftrace_stop. This does not enable
 146 * the function tracing if the function tracer is disabled. This only
 147 * sets the function tracer flag to continue calling the functions
 148 * from mcount.
 149 */
 150static inline void ftrace_start(void)
 151{
 152        function_trace_stop = 0;
 153}
 154
 155/*
 156 * The ftrace_ops must be a static and should also
 157 * be read_mostly.  These functions do modify read_mostly variables
 158 * so use them sparely. Never free an ftrace_op or modify the
 159 * next pointer after it has been registered. Even after unregistering
 160 * it, the next pointer may still be used internally.
 161 */
 162int register_ftrace_function(struct ftrace_ops *ops);
 163int unregister_ftrace_function(struct ftrace_ops *ops);
 164void clear_ftrace_function(void);
 165
 166/**
 167 * ftrace_function_local_enable - enable controlled ftrace_ops on current cpu
 168 *
 169 * This function enables tracing on current cpu by decreasing
 170 * the per cpu control variable.
 171 * It must be called with preemption disabled and only on ftrace_ops
 172 * registered with FTRACE_OPS_FL_CONTROL. If called without preemption
 173 * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
 174 */
 175static inline void ftrace_function_local_enable(struct ftrace_ops *ops)
 176{
 177        if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_CONTROL)))
 178                return;
 179
 180        (*this_cpu_ptr(ops->disabled))--;
 181}
 182
 183/**
 184 * ftrace_function_local_disable - enable controlled ftrace_ops on current cpu
 185 *
 186 * This function enables tracing on current cpu by decreasing
 187 * the per cpu control variable.
 188 * It must be called with preemption disabled and only on ftrace_ops
 189 * registered with FTRACE_OPS_FL_CONTROL. If called without preemption
 190 * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
 191 */
 192static inline void ftrace_function_local_disable(struct ftrace_ops *ops)
 193{
 194        if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_CONTROL)))
 195                return;
 196
 197        (*this_cpu_ptr(ops->disabled))++;
 198}
 199
 200/**
 201 * ftrace_function_local_disabled - returns ftrace_ops disabled value
 202 *                                  on current cpu
 203 *
 204 * This function returns value of ftrace_ops::disabled on current cpu.
 205 * It must be called with preemption disabled and only on ftrace_ops
 206 * registered with FTRACE_OPS_FL_CONTROL. If called without preemption
 207 * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
 208 */
 209static inline int ftrace_function_local_disabled(struct ftrace_ops *ops)
 210{
 211        WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_CONTROL));
 212        return *this_cpu_ptr(ops->disabled);
 213}
 214
 215extern void ftrace_stub(unsigned long a0, unsigned long a1,
 216                        struct ftrace_ops *op, struct pt_regs *regs);
 217
 218#else /* !CONFIG_FUNCTION_TRACER */
 219/*
 220 * (un)register_ftrace_function must be a macro since the ops parameter
 221 * must not be evaluated.
 222 */
 223#define register_ftrace_function(ops) ({ 0; })
 224#define unregister_ftrace_function(ops) ({ 0; })
 225static inline int ftrace_nr_registered_ops(void)
 226{
 227        return 0;
 228}
 229static inline void clear_ftrace_function(void) { }
 230static inline void ftrace_kill(void) { }
 231static inline void ftrace_stop(void) { }
 232static inline void ftrace_start(void) { }
 233#endif /* CONFIG_FUNCTION_TRACER */
 234
 235#ifdef CONFIG_STACK_TRACER
 236extern int stack_tracer_enabled;
 237int
 238stack_trace_sysctl(struct ctl_table *table, int write,
 239                   void __user *buffer, size_t *lenp,
 240                   loff_t *ppos);
 241#endif
 242
 243struct ftrace_func_command {
 244        struct list_head        list;
 245        char                    *name;
 246        int                     (*func)(struct ftrace_hash *hash,
 247                                        char *func, char *cmd,
 248                                        char *params, int enable);
 249};
 250
 251#ifdef CONFIG_DYNAMIC_FTRACE
 252
 253int ftrace_arch_code_modify_prepare(void);
 254int ftrace_arch_code_modify_post_process(void);
 255
 256void ftrace_bug(int err, unsigned long ip);
 257
 258struct seq_file;
 259
 260struct ftrace_probe_ops {
 261        void                    (*func)(unsigned long ip,
 262                                        unsigned long parent_ip,
 263                                        void **data);
 264        int                     (*callback)(unsigned long ip, void **data);
 265        void                    (*free)(void **data);
 266        int                     (*print)(struct seq_file *m,
 267                                         unsigned long ip,
 268                                         struct ftrace_probe_ops *ops,
 269                                         void *data);
 270};
 271
 272extern int
 273register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 274                              void *data);
 275extern void
 276unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 277                                void *data);
 278extern void
 279unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops);
 280extern void unregister_ftrace_function_probe_all(char *glob);
 281
 282extern int ftrace_text_reserved(void *start, void *end);
 283
 284extern int ftrace_nr_registered_ops(void);
 285
 286/*
 287 * The dyn_ftrace record's flags field is split into two parts.
 288 * the first part which is '0-FTRACE_REF_MAX' is a counter of
 289 * the number of callbacks that have registered the function that
 290 * the dyn_ftrace descriptor represents.
 291 *
 292 * The second part is a mask:
 293 *  ENABLED - the function is being traced
 294 *  REGS    - the record wants the function to save regs
 295 *  REGS_EN - the function is set up to save regs.
 296 *
 297 * When a new ftrace_ops is registered and wants a function to save
 298 * pt_regs, the rec->flag REGS is set. When the function has been
 299 * set up to save regs, the REG_EN flag is set. Once a function
 300 * starts saving regs it will do so until all ftrace_ops are removed
 301 * from tracing that function.
 302 */
 303enum {
 304        FTRACE_FL_ENABLED       = (1UL << 29),
 305        FTRACE_FL_REGS          = (1UL << 30),
 306        FTRACE_FL_REGS_EN       = (1UL << 31)
 307};
 308
 309#define FTRACE_FL_MASK          (0x7UL << 29)
 310#define FTRACE_REF_MAX          ((1UL << 29) - 1)
 311
 312struct dyn_ftrace {
 313        union {
 314                unsigned long           ip; /* address of mcount call-site */
 315                struct dyn_ftrace       *freelist;
 316        };
 317        unsigned long           flags;
 318        struct dyn_arch_ftrace          arch;
 319};
 320
 321int ftrace_force_update(void);
 322int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
 323                         int remove, int reset);
 324int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
 325                       int len, int reset);
 326int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
 327                        int len, int reset);
 328void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
 329void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
 330void ftrace_free_filter(struct ftrace_ops *ops);
 331
 332int register_ftrace_command(struct ftrace_func_command *cmd);
 333int unregister_ftrace_command(struct ftrace_func_command *cmd);
 334
 335enum {
 336        FTRACE_UPDATE_CALLS             = (1 << 0),
 337        FTRACE_DISABLE_CALLS            = (1 << 1),
 338        FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
 339        FTRACE_START_FUNC_RET           = (1 << 3),
 340        FTRACE_STOP_FUNC_RET            = (1 << 4),
 341};
 342
 343/*
 344 * The FTRACE_UPDATE_* enum is used to pass information back
 345 * from the ftrace_update_record() and ftrace_test_record()
 346 * functions. These are called by the code update routines
 347 * to find out what is to be done for a given function.
 348 *
 349 *  IGNORE           - The function is already what we want it to be
 350 *  MAKE_CALL        - Start tracing the function
 351 *  MODIFY_CALL      - Stop saving regs for the function
 352 *  MODIFY_CALL_REGS - Start saving regs for the function
 353 *  MAKE_NOP         - Stop tracing the function
 354 */
 355enum {
 356        FTRACE_UPDATE_IGNORE,
 357        FTRACE_UPDATE_MAKE_CALL,
 358        FTRACE_UPDATE_MODIFY_CALL,
 359        FTRACE_UPDATE_MODIFY_CALL_REGS,
 360        FTRACE_UPDATE_MAKE_NOP,
 361};
 362
 363enum {
 364        FTRACE_ITER_FILTER      = (1 << 0),
 365        FTRACE_ITER_NOTRACE     = (1 << 1),
 366        FTRACE_ITER_PRINTALL    = (1 << 2),
 367        FTRACE_ITER_DO_HASH     = (1 << 3),
 368        FTRACE_ITER_HASH        = (1 << 4),
 369        FTRACE_ITER_ENABLED     = (1 << 5),
 370};
 371
 372void arch_ftrace_update_code(int command);
 373
 374struct ftrace_rec_iter;
 375
 376struct ftrace_rec_iter *ftrace_rec_iter_start(void);
 377struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
 378struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);
 379
 380#define for_ftrace_rec_iter(iter)               \
 381        for (iter = ftrace_rec_iter_start();    \
 382             iter;                              \
 383             iter = ftrace_rec_iter_next(iter))
 384
 385
 386int ftrace_update_record(struct dyn_ftrace *rec, int enable);
 387int ftrace_test_record(struct dyn_ftrace *rec, int enable);
 388void ftrace_run_stop_machine(int command);
 389unsigned long ftrace_location(unsigned long ip);
 390
 391extern ftrace_func_t ftrace_trace_function;
 392
 393int ftrace_regex_open(struct ftrace_ops *ops, int flag,
 394                  struct inode *inode, struct file *file);
 395ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 396                            size_t cnt, loff_t *ppos);
 397ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 398                             size_t cnt, loff_t *ppos);
 399int ftrace_regex_release(struct inode *inode, struct file *file);
 400
 401void __init
 402ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
 403
 404/* defined in arch */
 405extern int ftrace_ip_converted(unsigned long ip);
 406extern int ftrace_dyn_arch_init(void *data);
 407extern void ftrace_replace_code(int enable);
 408extern int ftrace_update_ftrace_func(ftrace_func_t func);
 409extern void ftrace_caller(void);
 410extern void ftrace_regs_caller(void);
 411extern void ftrace_call(void);
 412extern void ftrace_regs_call(void);
 413extern void mcount_call(void);
 414
 415void ftrace_modify_all_code(int command);
 416
 417#ifndef FTRACE_ADDR
 418#define FTRACE_ADDR ((unsigned long)ftrace_caller)
 419#endif
 420
 421#ifndef FTRACE_REGS_ADDR
 422#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 423# define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller)
 424#else
 425# define FTRACE_REGS_ADDR FTRACE_ADDR
 426#endif
 427#endif
 428
 429#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 430extern void ftrace_graph_caller(void);
 431extern int ftrace_enable_ftrace_graph_caller(void);
 432extern int ftrace_disable_ftrace_graph_caller(void);
 433#else
 434static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
 435static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
 436#endif
 437
 438/**
 439 * ftrace_make_nop - convert code into nop
 440 * @mod: module structure if called by module load initialization
 441 * @rec: the mcount call site record
 442 * @addr: the address that the call site should be calling
 443 *
 444 * This is a very sensitive operation and great care needs
 445 * to be taken by the arch.  The operation should carefully
 446 * read the location, check to see if what is read is indeed
 447 * what we expect it to be, and then on success of the compare,
 448 * it should write to the location.
 449 *
 450 * The code segment at @rec->ip should be a caller to @addr
 451 *
 452 * Return must be:
 453 *  0 on success
 454 *  -EFAULT on error reading the location
 455 *  -EINVAL on a failed compare of the contents
 456 *  -EPERM  on error writing to the location
 457 * Any other value will be considered a failure.
 458 */
 459extern int ftrace_make_nop(struct module *mod,
 460                           struct dyn_ftrace *rec, unsigned long addr);
 461
 462/**
 463 * ftrace_make_call - convert a nop call site into a call to addr
 464 * @rec: the mcount call site record
 465 * @addr: the address that the call site should call
 466 *
 467 * This is a very sensitive operation and great care needs
 468 * to be taken by the arch.  The operation should carefully
 469 * read the location, check to see if what is read is indeed
 470 * what we expect it to be, and then on success of the compare,
 471 * it should write to the location.
 472 *
 473 * The code segment at @rec->ip should be a nop
 474 *
 475 * Return must be:
 476 *  0 on success
 477 *  -EFAULT on error reading the location
 478 *  -EINVAL on a failed compare of the contents
 479 *  -EPERM  on error writing to the location
 480 * Any other value will be considered a failure.
 481 */
 482extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
 483
 484#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 485/**
 486 * ftrace_modify_call - convert from one addr to another (no nop)
 487 * @rec: the mcount call site record
 488 * @old_addr: the address expected to be currently called to
 489 * @addr: the address to change to
 490 *
 491 * This is a very sensitive operation and great care needs
 492 * to be taken by the arch.  The operation should carefully
 493 * read the location, check to see if what is read is indeed
 494 * what we expect it to be, and then on success of the compare,
 495 * it should write to the location.
 496 *
 497 * The code segment at @rec->ip should be a caller to @old_addr
 498 *
 499 * Return must be:
 500 *  0 on success
 501 *  -EFAULT on error reading the location
 502 *  -EINVAL on a failed compare of the contents
 503 *  -EPERM  on error writing to the location
 504 * Any other value will be considered a failure.
 505 */
 506extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 507                              unsigned long addr);
 508#else
 509/* Should never be called */
 510static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 511                                     unsigned long addr)
 512{
 513        return -EINVAL;
 514}
 515#endif
 516
 517/* May be defined in arch */
 518extern int ftrace_arch_read_dyn_info(char *buf, int size);
 519
 520extern int skip_trace(unsigned long ip);
 521
 522extern void ftrace_disable_daemon(void);
 523extern void ftrace_enable_daemon(void);
 524#else /* CONFIG_DYNAMIC_FTRACE */
 525static inline int skip_trace(unsigned long ip) { return 0; }
 526static inline int ftrace_force_update(void) { return 0; }
 527static inline void ftrace_disable_daemon(void) { }
 528static inline void ftrace_enable_daemon(void) { }
 529static inline void ftrace_release_mod(struct module *mod) {}
 530static inline int register_ftrace_command(struct ftrace_func_command *cmd)
 531{
 532        return -EINVAL;
 533}
 534static inline int unregister_ftrace_command(char *cmd_name)
 535{
 536        return -EINVAL;
 537}
 538static inline int ftrace_text_reserved(void *start, void *end)
 539{
 540        return 0;
 541}
 542static inline unsigned long ftrace_location(unsigned long ip)
 543{
 544        return 0;
 545}
 546
 547/*
 548 * Again users of functions that have ftrace_ops may not
 549 * have them defined when ftrace is not enabled, but these
 550 * functions may still be called. Use a macro instead of inline.
 551 */
 552#define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
 553#define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
 554#define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; })
 555#define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
 556#define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
 557#define ftrace_free_filter(ops) do { } while (0)
 558
 559static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 560                            size_t cnt, loff_t *ppos) { return -ENODEV; }
 561static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 562                             size_t cnt, loff_t *ppos) { return -ENODEV; }
 563static inline loff_t ftrace_regex_lseek(struct file *file, loff_t offset, int whence)
 564{
 565        return -ENODEV;
 566}
 567static inline int
 568ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
 569#endif /* CONFIG_DYNAMIC_FTRACE */
 570
 571loff_t ftrace_filter_lseek(struct file *file, loff_t offset, int whence);
 572
 573/* totally disable ftrace - can not re-enable after this */
 574void ftrace_kill(void);
 575
 576static inline void tracer_disable(void)
 577{
 578#ifdef CONFIG_FUNCTION_TRACER
 579        ftrace_enabled = 0;
 580#endif
 581}
 582
 583/*
 584 * Ftrace disable/restore without lock. Some synchronization mechanism
 585 * must be used to prevent ftrace_enabled to be changed between
 586 * disable/restore.
 587 */
 588static inline int __ftrace_enabled_save(void)
 589{
 590#ifdef CONFIG_FUNCTION_TRACER
 591        int saved_ftrace_enabled = ftrace_enabled;
 592        ftrace_enabled = 0;
 593        return saved_ftrace_enabled;
 594#else
 595        return 0;
 596#endif
 597}
 598
 599static inline void __ftrace_enabled_restore(int enabled)
 600{
 601#ifdef CONFIG_FUNCTION_TRACER
 602        ftrace_enabled = enabled;
 603#endif
 604}
 605
 606#ifndef HAVE_ARCH_CALLER_ADDR
 607# ifdef CONFIG_FRAME_POINTER
 608#  define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
 609#  define CALLER_ADDR1 ((unsigned long)__builtin_return_address(1))
 610#  define CALLER_ADDR2 ((unsigned long)__builtin_return_address(2))
 611#  define CALLER_ADDR3 ((unsigned long)__builtin_return_address(3))
 612#  define CALLER_ADDR4 ((unsigned long)__builtin_return_address(4))
 613#  define CALLER_ADDR5 ((unsigned long)__builtin_return_address(5))
 614#  define CALLER_ADDR6 ((unsigned long)__builtin_return_address(6))
 615# else
 616#  define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
 617#  define CALLER_ADDR1 0UL
 618#  define CALLER_ADDR2 0UL
 619#  define CALLER_ADDR3 0UL
 620#  define CALLER_ADDR4 0UL
 621#  define CALLER_ADDR5 0UL
 622#  define CALLER_ADDR6 0UL
 623# endif
 624#endif /* ifndef HAVE_ARCH_CALLER_ADDR */
 625
 626#ifdef CONFIG_IRQSOFF_TRACER
 627  extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
 628  extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
 629#else
 630  static inline void time_hardirqs_on(unsigned long a0, unsigned long a1) { }
 631  static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { }
 632#endif
 633
 634#ifdef CONFIG_PREEMPT_TRACER
 635  extern void trace_preempt_on(unsigned long a0, unsigned long a1);
 636  extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 637#else
 638/*
 639 * Use defines instead of static inlines because some arches will make code out
 640 * of the CALLER_ADDR, when we really want these to be a real nop.
 641 */
 642# define trace_preempt_on(a0, a1) do { } while (0)
 643# define trace_preempt_off(a0, a1) do { } while (0)
 644#endif
 645
 646#ifdef CONFIG_FTRACE_MCOUNT_RECORD
 647extern void ftrace_init(void);
 648#else
 649static inline void ftrace_init(void) { }
 650#endif
 651
 652/*
 653 * Structure that defines an entry function trace.
 654 */
 655struct ftrace_graph_ent {
 656        unsigned long func; /* Current function */
 657        int depth;
 658};
 659
 660/*
 661 * Structure that defines a return function trace.
 662 */
 663struct ftrace_graph_ret {
 664        unsigned long func; /* Current function */
 665        unsigned long long calltime;
 666        unsigned long long rettime;
 667        /* Number of functions that overran the depth limit for current task */
 668        unsigned long overrun;
 669        int depth;
 670};
 671
 672/* Type of the callback handlers for tracing function graph*/
 673typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
 674typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
 675
 676#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 677
 678/* for init task */
 679#define INIT_FTRACE_GRAPH               .ret_stack = NULL,
 680
 681/*
 682 * Stack of return addresses for functions
 683 * of a thread.
 684 * Used in struct thread_info
 685 */
 686struct ftrace_ret_stack {
 687        unsigned long ret;
 688        unsigned long func;
 689        unsigned long long calltime;
 690        unsigned long long subtime;
 691        unsigned long fp;
 692};
 693
 694/*
 695 * Primary handler of a function return.
 696 * It relays on ftrace_return_to_handler.
 697 * Defined in entry_32/64.S
 698 */
 699extern void return_to_handler(void);
 700
 701extern int
 702ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
 703                         unsigned long frame_pointer);
 704
 705/*
 706 * Sometimes we don't want to trace a function with the function
 707 * graph tracer but we want them to keep traced by the usual function
 708 * tracer if the function graph tracer is not configured.
 709 */
 710#define __notrace_funcgraph             notrace
 711
 712/*
 713 * We want to which function is an entrypoint of a hardirq.
 714 * That will help us to put a signal on output.
 715 */
 716#define __irq_entry              __attribute__((__section__(".irqentry.text")))
 717
 718/* Limits of hardirq entrypoints */
 719extern char __irqentry_text_start[];
 720extern char __irqentry_text_end[];
 721
 722#define FTRACE_RETFUNC_DEPTH 50
 723#define FTRACE_RETSTACK_ALLOC_SIZE 32
 724extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 725                                trace_func_graph_ent_t entryfunc);
 726
 727extern void ftrace_graph_stop(void);
 728
 729/* The current handlers in use */
 730extern trace_func_graph_ret_t ftrace_graph_return;
 731extern trace_func_graph_ent_t ftrace_graph_entry;
 732
 733extern void unregister_ftrace_graph(void);
 734
 735extern void ftrace_graph_init_task(struct task_struct *t);
 736extern void ftrace_graph_exit_task(struct task_struct *t);
 737extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
 738
 739static inline int task_curr_ret_stack(struct task_struct *t)
 740{
 741        return t->curr_ret_stack;
 742}
 743
 744static inline void pause_graph_tracing(void)
 745{
 746        atomic_inc(&current->tracing_graph_pause);
 747}
 748
 749static inline void unpause_graph_tracing(void)
 750{
 751        atomic_dec(&current->tracing_graph_pause);
 752}
 753#else /* !CONFIG_FUNCTION_GRAPH_TRACER */
 754
 755#define __notrace_funcgraph
 756#define __irq_entry
 757#define INIT_FTRACE_GRAPH
 758
 759static inline void ftrace_graph_init_task(struct task_struct *t) { }
 760static inline void ftrace_graph_exit_task(struct task_struct *t) { }
 761static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
 762
 763static inline int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 764                          trace_func_graph_ent_t entryfunc)
 765{
 766        return -1;
 767}
 768static inline void unregister_ftrace_graph(void) { }
 769
 770static inline int task_curr_ret_stack(struct task_struct *tsk)
 771{
 772        return -1;
 773}
 774
 775static inline void pause_graph_tracing(void) { }
 776static inline void unpause_graph_tracing(void) { }
 777#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 778
 779#ifdef CONFIG_TRACING
 780
 781/* flags for current->trace */
 782enum {
 783        TSK_TRACE_FL_TRACE_BIT  = 0,
 784        TSK_TRACE_FL_GRAPH_BIT  = 1,
 785};
 786enum {
 787        TSK_TRACE_FL_TRACE      = 1 << TSK_TRACE_FL_TRACE_BIT,
 788        TSK_TRACE_FL_GRAPH      = 1 << TSK_TRACE_FL_GRAPH_BIT,
 789};
 790
 791static inline void set_tsk_trace_trace(struct task_struct *tsk)
 792{
 793        set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 794}
 795
 796static inline void clear_tsk_trace_trace(struct task_struct *tsk)
 797{
 798        clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 799}
 800
 801static inline int test_tsk_trace_trace(struct task_struct *tsk)
 802{
 803        return tsk->trace & TSK_TRACE_FL_TRACE;
 804}
 805
 806static inline void set_tsk_trace_graph(struct task_struct *tsk)
 807{
 808        set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 809}
 810
 811static inline void clear_tsk_trace_graph(struct task_struct *tsk)
 812{
 813        clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 814}
 815
 816static inline int test_tsk_trace_graph(struct task_struct *tsk)
 817{
 818        return tsk->trace & TSK_TRACE_FL_GRAPH;
 819}
 820
 821enum ftrace_dump_mode;
 822
 823extern enum ftrace_dump_mode ftrace_dump_on_oops;
 824
 825#ifdef CONFIG_PREEMPT
 826#define INIT_TRACE_RECURSION            .trace_recursion = 0,
 827#endif
 828
 829#endif /* CONFIG_TRACING */
 830
 831#ifndef INIT_TRACE_RECURSION
 832#define INIT_TRACE_RECURSION
 833#endif
 834
 835#ifdef CONFIG_FTRACE_SYSCALLS
 836
 837unsigned long arch_syscall_addr(int nr);
 838
 839#endif /* CONFIG_FTRACE_SYSCALLS */
 840
 841#endif /* _LINUX_FTRACE_H */
 842
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