linux/include/linux/ftrace.h
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   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * Ftrace header.  For implementation details beyond the random comments
   4 * scattered below, see: Documentation/trace/ftrace-design.rst
   5 */
   6
   7#ifndef _LINUX_FTRACE_H
   8#define _LINUX_FTRACE_H
   9
  10#include <linux/trace_recursion.h>
  11#include <linux/trace_clock.h>
  12#include <linux/kallsyms.h>
  13#include <linux/linkage.h>
  14#include <linux/bitops.h>
  15#include <linux/ptrace.h>
  16#include <linux/ktime.h>
  17#include <linux/sched.h>
  18#include <linux/types.h>
  19#include <linux/init.h>
  20#include <linux/fs.h>
  21
  22#include <asm/ftrace.h>
  23
  24/*
  25 * If the arch supports passing the variable contents of
  26 * function_trace_op as the third parameter back from the
  27 * mcount call, then the arch should define this as 1.
  28 */
  29#ifndef ARCH_SUPPORTS_FTRACE_OPS
  30#define ARCH_SUPPORTS_FTRACE_OPS 0
  31#endif
  32
  33/*
  34 * If the arch's mcount caller does not support all of ftrace's
  35 * features, then it must call an indirect function that
  36 * does. Or at least does enough to prevent any unwelcome side effects.
  37 */
  38#if !ARCH_SUPPORTS_FTRACE_OPS
  39# define FTRACE_FORCE_LIST_FUNC 1
  40#else
  41# define FTRACE_FORCE_LIST_FUNC 0
  42#endif
  43
  44/* Main tracing buffer and events set up */
  45#ifdef CONFIG_TRACING
  46void trace_init(void);
  47void early_trace_init(void);
  48#else
  49static inline void trace_init(void) { }
  50static inline void early_trace_init(void) { }
  51#endif
  52
  53struct module;
  54struct ftrace_hash;
  55struct ftrace_direct_func;
  56
  57#if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_MODULES) && \
  58        defined(CONFIG_DYNAMIC_FTRACE)
  59const char *
  60ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
  61                   unsigned long *off, char **modname, char *sym);
  62#else
  63static inline const char *
  64ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
  65                   unsigned long *off, char **modname, char *sym)
  66{
  67        return NULL;
  68}
  69#endif
  70
  71#if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_DYNAMIC_FTRACE)
  72int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
  73                           char *type, char *name,
  74                           char *module_name, int *exported);
  75#else
  76static inline int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
  77                                         char *type, char *name,
  78                                         char *module_name, int *exported)
  79{
  80        return -1;
  81}
  82#endif
  83
  84#ifdef CONFIG_FUNCTION_TRACER
  85
  86extern int ftrace_enabled;
  87extern int
  88ftrace_enable_sysctl(struct ctl_table *table, int write,
  89                     void *buffer, size_t *lenp, loff_t *ppos);
  90
  91struct ftrace_ops;
  92
  93#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
  94
  95struct ftrace_regs {
  96        struct pt_regs          regs;
  97};
  98#define arch_ftrace_get_regs(fregs) (&(fregs)->regs)
  99
 100/*
 101 * ftrace_instruction_pointer_set() is to be defined by the architecture
 102 * if to allow setting of the instruction pointer from the ftrace_regs
 103 * when HAVE_DYNAMIC_FTRACE_WITH_ARGS is set and it supports
 104 * live kernel patching.
 105 */
 106#define ftrace_instruction_pointer_set(fregs, ip) do { } while (0)
 107#endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
 108
 109static __always_inline struct pt_regs *ftrace_get_regs(struct ftrace_regs *fregs)
 110{
 111        if (!fregs)
 112                return NULL;
 113
 114        return arch_ftrace_get_regs(fregs);
 115}
 116
 117typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
 118                              struct ftrace_ops *op, struct ftrace_regs *fregs);
 119
 120ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops);
 121
 122/*
 123 * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are
 124 * set in the flags member.
 125 * CONTROL, SAVE_REGS, SAVE_REGS_IF_SUPPORTED, RECURSION, STUB and
 126 * IPMODIFY are a kind of attribute flags which can be set only before
 127 * registering the ftrace_ops, and can not be modified while registered.
 128 * Changing those attribute flags after registering ftrace_ops will
 129 * cause unexpected results.
 130 *
 131 * ENABLED - set/unset when ftrace_ops is registered/unregistered
 132 * DYNAMIC - set when ftrace_ops is registered to denote dynamically
 133 *           allocated ftrace_ops which need special care
 134 * SAVE_REGS - The ftrace_ops wants regs saved at each function called
 135 *            and passed to the callback. If this flag is set, but the
 136 *            architecture does not support passing regs
 137 *            (CONFIG_DYNAMIC_FTRACE_WITH_REGS is not defined), then the
 138 *            ftrace_ops will fail to register, unless the next flag
 139 *            is set.
 140 * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the
 141 *            handler can handle an arch that does not save regs
 142 *            (the handler tests if regs == NULL), then it can set
 143 *            this flag instead. It will not fail registering the ftrace_ops
 144 *            but, the regs field will be NULL if the arch does not support
 145 *            passing regs to the handler.
 146 *            Note, if this flag is set, the SAVE_REGS flag will automatically
 147 *            get set upon registering the ftrace_ops, if the arch supports it.
 148 * RECURSION - The ftrace_ops can set this to tell the ftrace infrastructure
 149 *            that the call back needs recursion protection. If it does
 150 *            not set this, then the ftrace infrastructure will assume
 151 *            that the callback can handle recursion on its own.
 152 * STUB   - The ftrace_ops is just a place holder.
 153 * INITIALIZED - The ftrace_ops has already been initialized (first use time
 154 *            register_ftrace_function() is called, it will initialized the ops)
 155 * DELETED - The ops are being deleted, do not let them be registered again.
 156 * ADDING  - The ops is in the process of being added.
 157 * REMOVING - The ops is in the process of being removed.
 158 * MODIFYING - The ops is in the process of changing its filter functions.
 159 * ALLOC_TRAMP - A dynamic trampoline was allocated by the core code.
 160 *            The arch specific code sets this flag when it allocated a
 161 *            trampoline. This lets the arch know that it can update the
 162 *            trampoline in case the callback function changes.
 163 *            The ftrace_ops trampoline can be set by the ftrace users, and
 164 *            in such cases the arch must not modify it. Only the arch ftrace
 165 *            core code should set this flag.
 166 * IPMODIFY - The ops can modify the IP register. This can only be set with
 167 *            SAVE_REGS. If another ops with this flag set is already registered
 168 *            for any of the functions that this ops will be registered for, then
 169 *            this ops will fail to register or set_filter_ip.
 170 * PID     - Is affected by set_ftrace_pid (allows filtering on those pids)
 171 * RCU     - Set when the ops can only be called when RCU is watching.
 172 * TRACE_ARRAY - The ops->private points to a trace_array descriptor.
 173 * PERMANENT - Set when the ops is permanent and should not be affected by
 174 *             ftrace_enabled.
 175 * DIRECT - Used by the direct ftrace_ops helper for direct functions
 176 *            (internal ftrace only, should not be used by others)
 177 */
 178enum {
 179        FTRACE_OPS_FL_ENABLED                   = BIT(0),
 180        FTRACE_OPS_FL_DYNAMIC                   = BIT(1),
 181        FTRACE_OPS_FL_SAVE_REGS                 = BIT(2),
 182        FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED    = BIT(3),
 183        FTRACE_OPS_FL_RECURSION                 = BIT(4),
 184        FTRACE_OPS_FL_STUB                      = BIT(5),
 185        FTRACE_OPS_FL_INITIALIZED               = BIT(6),
 186        FTRACE_OPS_FL_DELETED                   = BIT(7),
 187        FTRACE_OPS_FL_ADDING                    = BIT(8),
 188        FTRACE_OPS_FL_REMOVING                  = BIT(9),
 189        FTRACE_OPS_FL_MODIFYING                 = BIT(10),
 190        FTRACE_OPS_FL_ALLOC_TRAMP               = BIT(11),
 191        FTRACE_OPS_FL_IPMODIFY                  = BIT(12),
 192        FTRACE_OPS_FL_PID                       = BIT(13),
 193        FTRACE_OPS_FL_RCU                       = BIT(14),
 194        FTRACE_OPS_FL_TRACE_ARRAY               = BIT(15),
 195        FTRACE_OPS_FL_PERMANENT                 = BIT(16),
 196        FTRACE_OPS_FL_DIRECT                    = BIT(17),
 197};
 198
 199#ifdef CONFIG_DYNAMIC_FTRACE
 200/* The hash used to know what functions callbacks trace */
 201struct ftrace_ops_hash {
 202        struct ftrace_hash __rcu        *notrace_hash;
 203        struct ftrace_hash __rcu        *filter_hash;
 204        struct mutex                    regex_lock;
 205};
 206
 207void ftrace_free_init_mem(void);
 208void ftrace_free_mem(struct module *mod, void *start, void *end);
 209#else
 210static inline void ftrace_free_init_mem(void) { }
 211static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }
 212#endif
 213
 214/*
 215 * Note, ftrace_ops can be referenced outside of RCU protection, unless
 216 * the RCU flag is set. If ftrace_ops is allocated and not part of kernel
 217 * core data, the unregistering of it will perform a scheduling on all CPUs
 218 * to make sure that there are no more users. Depending on the load of the
 219 * system that may take a bit of time.
 220 *
 221 * Any private data added must also take care not to be freed and if private
 222 * data is added to a ftrace_ops that is in core code, the user of the
 223 * ftrace_ops must perform a schedule_on_each_cpu() before freeing it.
 224 */
 225struct ftrace_ops {
 226        ftrace_func_t                   func;
 227        struct ftrace_ops __rcu         *next;
 228        unsigned long                   flags;
 229        void                            *private;
 230        ftrace_func_t                   saved_func;
 231#ifdef CONFIG_DYNAMIC_FTRACE
 232        struct ftrace_ops_hash          local_hash;
 233        struct ftrace_ops_hash          *func_hash;
 234        struct ftrace_ops_hash          old_hash;
 235        unsigned long                   trampoline;
 236        unsigned long                   trampoline_size;
 237        struct list_head                list;
 238#endif
 239};
 240
 241extern struct ftrace_ops __rcu *ftrace_ops_list;
 242extern struct ftrace_ops ftrace_list_end;
 243
 244/*
 245 * Traverse the ftrace_ops_list, invoking all entries.  The reason that we
 246 * can use rcu_dereference_raw_check() is that elements removed from this list
 247 * are simply leaked, so there is no need to interact with a grace-period
 248 * mechanism.  The rcu_dereference_raw_check() calls are needed to handle
 249 * concurrent insertions into the ftrace_ops_list.
 250 *
 251 * Silly Alpha and silly pointer-speculation compiler optimizations!
 252 */
 253#define do_for_each_ftrace_op(op, list)                 \
 254        op = rcu_dereference_raw_check(list);                   \
 255        do
 256
 257/*
 258 * Optimized for just a single item in the list (as that is the normal case).
 259 */
 260#define while_for_each_ftrace_op(op)                            \
 261        while (likely(op = rcu_dereference_raw_check((op)->next)) &&    \
 262               unlikely((op) != &ftrace_list_end))
 263
 264/*
 265 * Type of the current tracing.
 266 */
 267enum ftrace_tracing_type_t {
 268        FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
 269        FTRACE_TYPE_RETURN,     /* Hook the return of the function */
 270};
 271
 272/* Current tracing type, default is FTRACE_TYPE_ENTER */
 273extern enum ftrace_tracing_type_t ftrace_tracing_type;
 274
 275/*
 276 * The ftrace_ops must be a static and should also
 277 * be read_mostly.  These functions do modify read_mostly variables
 278 * so use them sparely. Never free an ftrace_op or modify the
 279 * next pointer after it has been registered. Even after unregistering
 280 * it, the next pointer may still be used internally.
 281 */
 282int register_ftrace_function(struct ftrace_ops *ops);
 283int unregister_ftrace_function(struct ftrace_ops *ops);
 284
 285extern void ftrace_stub(unsigned long a0, unsigned long a1,
 286                        struct ftrace_ops *op, struct ftrace_regs *fregs);
 287
 288#else /* !CONFIG_FUNCTION_TRACER */
 289/*
 290 * (un)register_ftrace_function must be a macro since the ops parameter
 291 * must not be evaluated.
 292 */
 293#define register_ftrace_function(ops) ({ 0; })
 294#define unregister_ftrace_function(ops) ({ 0; })
 295static inline void ftrace_kill(void) { }
 296static inline void ftrace_free_init_mem(void) { }
 297static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }
 298#endif /* CONFIG_FUNCTION_TRACER */
 299
 300struct ftrace_func_entry {
 301        struct hlist_node hlist;
 302        unsigned long ip;
 303        unsigned long direct; /* for direct lookup only */
 304};
 305
 306struct dyn_ftrace;
 307
 308#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
 309extern int ftrace_direct_func_count;
 310int register_ftrace_direct(unsigned long ip, unsigned long addr);
 311int unregister_ftrace_direct(unsigned long ip, unsigned long addr);
 312int modify_ftrace_direct(unsigned long ip, unsigned long old_addr, unsigned long new_addr);
 313struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr);
 314int ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
 315                                struct dyn_ftrace *rec,
 316                                unsigned long old_addr,
 317                                unsigned long new_addr);
 318unsigned long ftrace_find_rec_direct(unsigned long ip);
 319#else
 320# define ftrace_direct_func_count 0
 321static inline int register_ftrace_direct(unsigned long ip, unsigned long addr)
 322{
 323        return -ENOTSUPP;
 324}
 325static inline int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
 326{
 327        return -ENOTSUPP;
 328}
 329static inline int modify_ftrace_direct(unsigned long ip,
 330                                       unsigned long old_addr, unsigned long new_addr)
 331{
 332        return -ENOTSUPP;
 333}
 334static inline struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr)
 335{
 336        return NULL;
 337}
 338static inline int ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
 339                                              struct dyn_ftrace *rec,
 340                                              unsigned long old_addr,
 341                                              unsigned long new_addr)
 342{
 343        return -ENODEV;
 344}
 345static inline unsigned long ftrace_find_rec_direct(unsigned long ip)
 346{
 347        return 0;
 348}
 349#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
 350
 351#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
 352/*
 353 * This must be implemented by the architecture.
 354 * It is the way the ftrace direct_ops helper, when called
 355 * via ftrace (because there's other callbacks besides the
 356 * direct call), can inform the architecture's trampoline that this
 357 * routine has a direct caller, and what the caller is.
 358 *
 359 * For example, in x86, it returns the direct caller
 360 * callback function via the regs->orig_ax parameter.
 361 * Then in the ftrace trampoline, if this is set, it makes
 362 * the return from the trampoline jump to the direct caller
 363 * instead of going back to the function it just traced.
 364 */
 365static inline void arch_ftrace_set_direct_caller(struct pt_regs *regs,
 366                                                 unsigned long addr) { }
 367#endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
 368
 369#ifdef CONFIG_STACK_TRACER
 370
 371extern int stack_tracer_enabled;
 372
 373int stack_trace_sysctl(struct ctl_table *table, int write, void *buffer,
 374                       size_t *lenp, loff_t *ppos);
 375
 376/* DO NOT MODIFY THIS VARIABLE DIRECTLY! */
 377DECLARE_PER_CPU(int, disable_stack_tracer);
 378
 379/**
 380 * stack_tracer_disable - temporarily disable the stack tracer
 381 *
 382 * There's a few locations (namely in RCU) where stack tracing
 383 * cannot be executed. This function is used to disable stack
 384 * tracing during those critical sections.
 385 *
 386 * This function must be called with preemption or interrupts
 387 * disabled and stack_tracer_enable() must be called shortly after
 388 * while preemption or interrupts are still disabled.
 389 */
 390static inline void stack_tracer_disable(void)
 391{
 392        /* Preemption or interrupts must be disabled */
 393        if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
 394                WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
 395        this_cpu_inc(disable_stack_tracer);
 396}
 397
 398/**
 399 * stack_tracer_enable - re-enable the stack tracer
 400 *
 401 * After stack_tracer_disable() is called, stack_tracer_enable()
 402 * must be called shortly afterward.
 403 */
 404static inline void stack_tracer_enable(void)
 405{
 406        if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
 407                WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
 408        this_cpu_dec(disable_stack_tracer);
 409}
 410#else
 411static inline void stack_tracer_disable(void) { }
 412static inline void stack_tracer_enable(void) { }
 413#endif
 414
 415#ifdef CONFIG_DYNAMIC_FTRACE
 416
 417int ftrace_arch_code_modify_prepare(void);
 418int ftrace_arch_code_modify_post_process(void);
 419
 420enum ftrace_bug_type {
 421        FTRACE_BUG_UNKNOWN,
 422        FTRACE_BUG_INIT,
 423        FTRACE_BUG_NOP,
 424        FTRACE_BUG_CALL,
 425        FTRACE_BUG_UPDATE,
 426};
 427extern enum ftrace_bug_type ftrace_bug_type;
 428
 429/*
 430 * Archs can set this to point to a variable that holds the value that was
 431 * expected at the call site before calling ftrace_bug().
 432 */
 433extern const void *ftrace_expected;
 434
 435void ftrace_bug(int err, struct dyn_ftrace *rec);
 436
 437struct seq_file;
 438
 439extern int ftrace_text_reserved(const void *start, const void *end);
 440
 441struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr);
 442
 443bool is_ftrace_trampoline(unsigned long addr);
 444
 445/*
 446 * The dyn_ftrace record's flags field is split into two parts.
 447 * the first part which is '0-FTRACE_REF_MAX' is a counter of
 448 * the number of callbacks that have registered the function that
 449 * the dyn_ftrace descriptor represents.
 450 *
 451 * The second part is a mask:
 452 *  ENABLED - the function is being traced
 453 *  REGS    - the record wants the function to save regs
 454 *  REGS_EN - the function is set up to save regs.
 455 *  IPMODIFY - the record allows for the IP address to be changed.
 456 *  DISABLED - the record is not ready to be touched yet
 457 *  DIRECT   - there is a direct function to call
 458 *
 459 * When a new ftrace_ops is registered and wants a function to save
 460 * pt_regs, the rec->flags REGS is set. When the function has been
 461 * set up to save regs, the REG_EN flag is set. Once a function
 462 * starts saving regs it will do so until all ftrace_ops are removed
 463 * from tracing that function.
 464 */
 465enum {
 466        FTRACE_FL_ENABLED       = (1UL << 31),
 467        FTRACE_FL_REGS          = (1UL << 30),
 468        FTRACE_FL_REGS_EN       = (1UL << 29),
 469        FTRACE_FL_TRAMP         = (1UL << 28),
 470        FTRACE_FL_TRAMP_EN      = (1UL << 27),
 471        FTRACE_FL_IPMODIFY      = (1UL << 26),
 472        FTRACE_FL_DISABLED      = (1UL << 25),
 473        FTRACE_FL_DIRECT        = (1UL << 24),
 474        FTRACE_FL_DIRECT_EN     = (1UL << 23),
 475};
 476
 477#define FTRACE_REF_MAX_SHIFT    23
 478#define FTRACE_REF_MAX          ((1UL << FTRACE_REF_MAX_SHIFT) - 1)
 479
 480#define ftrace_rec_count(rec)   ((rec)->flags & FTRACE_REF_MAX)
 481
 482struct dyn_ftrace {
 483        unsigned long           ip; /* address of mcount call-site */
 484        unsigned long           flags;
 485        struct dyn_arch_ftrace  arch;
 486};
 487
 488int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
 489                         int remove, int reset);
 490int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
 491                       int len, int reset);
 492int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
 493                        int len, int reset);
 494void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
 495void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
 496void ftrace_free_filter(struct ftrace_ops *ops);
 497void ftrace_ops_set_global_filter(struct ftrace_ops *ops);
 498
 499enum {
 500        FTRACE_UPDATE_CALLS             = (1 << 0),
 501        FTRACE_DISABLE_CALLS            = (1 << 1),
 502        FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
 503        FTRACE_START_FUNC_RET           = (1 << 3),
 504        FTRACE_STOP_FUNC_RET            = (1 << 4),
 505        FTRACE_MAY_SLEEP                = (1 << 5),
 506};
 507
 508/*
 509 * The FTRACE_UPDATE_* enum is used to pass information back
 510 * from the ftrace_update_record() and ftrace_test_record()
 511 * functions. These are called by the code update routines
 512 * to find out what is to be done for a given function.
 513 *
 514 *  IGNORE           - The function is already what we want it to be
 515 *  MAKE_CALL        - Start tracing the function
 516 *  MODIFY_CALL      - Stop saving regs for the function
 517 *  MAKE_NOP         - Stop tracing the function
 518 */
 519enum {
 520        FTRACE_UPDATE_IGNORE,
 521        FTRACE_UPDATE_MAKE_CALL,
 522        FTRACE_UPDATE_MODIFY_CALL,
 523        FTRACE_UPDATE_MAKE_NOP,
 524};
 525
 526enum {
 527        FTRACE_ITER_FILTER      = (1 << 0),
 528        FTRACE_ITER_NOTRACE     = (1 << 1),
 529        FTRACE_ITER_PRINTALL    = (1 << 2),
 530        FTRACE_ITER_DO_PROBES   = (1 << 3),
 531        FTRACE_ITER_PROBE       = (1 << 4),
 532        FTRACE_ITER_MOD         = (1 << 5),
 533        FTRACE_ITER_ENABLED     = (1 << 6),
 534};
 535
 536void arch_ftrace_update_code(int command);
 537void arch_ftrace_update_trampoline(struct ftrace_ops *ops);
 538void *arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec);
 539void arch_ftrace_trampoline_free(struct ftrace_ops *ops);
 540
 541struct ftrace_rec_iter;
 542
 543struct ftrace_rec_iter *ftrace_rec_iter_start(void);
 544struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
 545struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);
 546
 547#define for_ftrace_rec_iter(iter)               \
 548        for (iter = ftrace_rec_iter_start();    \
 549             iter;                              \
 550             iter = ftrace_rec_iter_next(iter))
 551
 552
 553int ftrace_update_record(struct dyn_ftrace *rec, bool enable);
 554int ftrace_test_record(struct dyn_ftrace *rec, bool enable);
 555void ftrace_run_stop_machine(int command);
 556unsigned long ftrace_location(unsigned long ip);
 557unsigned long ftrace_location_range(unsigned long start, unsigned long end);
 558unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec);
 559unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec);
 560
 561extern ftrace_func_t ftrace_trace_function;
 562
 563int ftrace_regex_open(struct ftrace_ops *ops, int flag,
 564                  struct inode *inode, struct file *file);
 565ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 566                            size_t cnt, loff_t *ppos);
 567ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 568                             size_t cnt, loff_t *ppos);
 569int ftrace_regex_release(struct inode *inode, struct file *file);
 570
 571void __init
 572ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
 573
 574/* defined in arch */
 575extern int ftrace_ip_converted(unsigned long ip);
 576extern int ftrace_dyn_arch_init(void);
 577extern void ftrace_replace_code(int enable);
 578extern int ftrace_update_ftrace_func(ftrace_func_t func);
 579extern void ftrace_caller(void);
 580extern void ftrace_regs_caller(void);
 581extern void ftrace_call(void);
 582extern void ftrace_regs_call(void);
 583extern void mcount_call(void);
 584
 585void ftrace_modify_all_code(int command);
 586
 587#ifndef FTRACE_ADDR
 588#define FTRACE_ADDR ((unsigned long)ftrace_caller)
 589#endif
 590
 591#ifndef FTRACE_GRAPH_ADDR
 592#define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller)
 593#endif
 594
 595#ifndef FTRACE_REGS_ADDR
 596#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 597# define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller)
 598#else
 599# define FTRACE_REGS_ADDR FTRACE_ADDR
 600#endif
 601#endif
 602
 603/*
 604 * If an arch would like functions that are only traced
 605 * by the function graph tracer to jump directly to its own
 606 * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR
 607 * to be that address to jump to.
 608 */
 609#ifndef FTRACE_GRAPH_TRAMP_ADDR
 610#define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0)
 611#endif
 612
 613#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 614extern void ftrace_graph_caller(void);
 615extern int ftrace_enable_ftrace_graph_caller(void);
 616extern int ftrace_disable_ftrace_graph_caller(void);
 617#else
 618static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
 619static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
 620#endif
 621
 622/**
 623 * ftrace_make_nop - convert code into nop
 624 * @mod: module structure if called by module load initialization
 625 * @rec: the call site record (e.g. mcount/fentry)
 626 * @addr: the address that the call site should be calling
 627 *
 628 * This is a very sensitive operation and great care needs
 629 * to be taken by the arch.  The operation should carefully
 630 * read the location, check to see if what is read is indeed
 631 * what we expect it to be, and then on success of the compare,
 632 * it should write to the location.
 633 *
 634 * The code segment at @rec->ip should be a caller to @addr
 635 *
 636 * Return must be:
 637 *  0 on success
 638 *  -EFAULT on error reading the location
 639 *  -EINVAL on a failed compare of the contents
 640 *  -EPERM  on error writing to the location
 641 * Any other value will be considered a failure.
 642 */
 643extern int ftrace_make_nop(struct module *mod,
 644                           struct dyn_ftrace *rec, unsigned long addr);
 645
 646
 647/**
 648 * ftrace_init_nop - initialize a nop call site
 649 * @mod: module structure if called by module load initialization
 650 * @rec: the call site record (e.g. mcount/fentry)
 651 *
 652 * This is a very sensitive operation and great care needs
 653 * to be taken by the arch.  The operation should carefully
 654 * read the location, check to see if what is read is indeed
 655 * what we expect it to be, and then on success of the compare,
 656 * it should write to the location.
 657 *
 658 * The code segment at @rec->ip should contain the contents created by
 659 * the compiler
 660 *
 661 * Return must be:
 662 *  0 on success
 663 *  -EFAULT on error reading the location
 664 *  -EINVAL on a failed compare of the contents
 665 *  -EPERM  on error writing to the location
 666 * Any other value will be considered a failure.
 667 */
 668#ifndef ftrace_init_nop
 669static inline int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec)
 670{
 671        return ftrace_make_nop(mod, rec, MCOUNT_ADDR);
 672}
 673#endif
 674
 675/**
 676 * ftrace_make_call - convert a nop call site into a call to addr
 677 * @rec: the call site record (e.g. mcount/fentry)
 678 * @addr: the address that the call site should call
 679 *
 680 * This is a very sensitive operation and great care needs
 681 * to be taken by the arch.  The operation should carefully
 682 * read the location, check to see if what is read is indeed
 683 * what we expect it to be, and then on success of the compare,
 684 * it should write to the location.
 685 *
 686 * The code segment at @rec->ip should be a nop
 687 *
 688 * Return must be:
 689 *  0 on success
 690 *  -EFAULT on error reading the location
 691 *  -EINVAL on a failed compare of the contents
 692 *  -EPERM  on error writing to the location
 693 * Any other value will be considered a failure.
 694 */
 695extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
 696
 697#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 698/**
 699 * ftrace_modify_call - convert from one addr to another (no nop)
 700 * @rec: the call site record (e.g. mcount/fentry)
 701 * @old_addr: the address expected to be currently called to
 702 * @addr: the address to change to
 703 *
 704 * This is a very sensitive operation and great care needs
 705 * to be taken by the arch.  The operation should carefully
 706 * read the location, check to see if what is read is indeed
 707 * what we expect it to be, and then on success of the compare,
 708 * it should write to the location.
 709 *
 710 * The code segment at @rec->ip should be a caller to @old_addr
 711 *
 712 * Return must be:
 713 *  0 on success
 714 *  -EFAULT on error reading the location
 715 *  -EINVAL on a failed compare of the contents
 716 *  -EPERM  on error writing to the location
 717 * Any other value will be considered a failure.
 718 */
 719extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 720                              unsigned long addr);
 721#else
 722/* Should never be called */
 723static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 724                                     unsigned long addr)
 725{
 726        return -EINVAL;
 727}
 728#endif
 729
 730/* May be defined in arch */
 731extern int ftrace_arch_read_dyn_info(char *buf, int size);
 732
 733extern int skip_trace(unsigned long ip);
 734extern void ftrace_module_init(struct module *mod);
 735extern void ftrace_module_enable(struct module *mod);
 736extern void ftrace_release_mod(struct module *mod);
 737
 738extern void ftrace_disable_daemon(void);
 739extern void ftrace_enable_daemon(void);
 740#else /* CONFIG_DYNAMIC_FTRACE */
 741static inline int skip_trace(unsigned long ip) { return 0; }
 742static inline void ftrace_disable_daemon(void) { }
 743static inline void ftrace_enable_daemon(void) { }
 744static inline void ftrace_module_init(struct module *mod) { }
 745static inline void ftrace_module_enable(struct module *mod) { }
 746static inline void ftrace_release_mod(struct module *mod) { }
 747static inline int ftrace_text_reserved(const void *start, const void *end)
 748{
 749        return 0;
 750}
 751static inline unsigned long ftrace_location(unsigned long ip)
 752{
 753        return 0;
 754}
 755
 756/*
 757 * Again users of functions that have ftrace_ops may not
 758 * have them defined when ftrace is not enabled, but these
 759 * functions may still be called. Use a macro instead of inline.
 760 */
 761#define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
 762#define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
 763#define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; })
 764#define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
 765#define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
 766#define ftrace_free_filter(ops) do { } while (0)
 767#define ftrace_ops_set_global_filter(ops) do { } while (0)
 768
 769static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 770                            size_t cnt, loff_t *ppos) { return -ENODEV; }
 771static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 772                             size_t cnt, loff_t *ppos) { return -ENODEV; }
 773static inline int
 774ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
 775
 776static inline bool is_ftrace_trampoline(unsigned long addr)
 777{
 778        return false;
 779}
 780#endif /* CONFIG_DYNAMIC_FTRACE */
 781
 782/* totally disable ftrace - can not re-enable after this */
 783void ftrace_kill(void);
 784
 785static inline void tracer_disable(void)
 786{
 787#ifdef CONFIG_FUNCTION_TRACER
 788        ftrace_enabled = 0;
 789#endif
 790}
 791
 792/*
 793 * Ftrace disable/restore without lock. Some synchronization mechanism
 794 * must be used to prevent ftrace_enabled to be changed between
 795 * disable/restore.
 796 */
 797static inline int __ftrace_enabled_save(void)
 798{
 799#ifdef CONFIG_FUNCTION_TRACER
 800        int saved_ftrace_enabled = ftrace_enabled;
 801        ftrace_enabled = 0;
 802        return saved_ftrace_enabled;
 803#else
 804        return 0;
 805#endif
 806}
 807
 808static inline void __ftrace_enabled_restore(int enabled)
 809{
 810#ifdef CONFIG_FUNCTION_TRACER
 811        ftrace_enabled = enabled;
 812#endif
 813}
 814
 815/* All archs should have this, but we define it for consistency */
 816#ifndef ftrace_return_address0
 817# define ftrace_return_address0 __builtin_return_address(0)
 818#endif
 819
 820/* Archs may use other ways for ADDR1 and beyond */
 821#ifndef ftrace_return_address
 822# ifdef CONFIG_FRAME_POINTER
 823#  define ftrace_return_address(n) __builtin_return_address(n)
 824# else
 825#  define ftrace_return_address(n) 0UL
 826# endif
 827#endif
 828
 829#define CALLER_ADDR0 ((unsigned long)ftrace_return_address0)
 830#define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1))
 831#define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2))
 832#define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3))
 833#define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4))
 834#define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5))
 835#define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6))
 836
 837static inline unsigned long get_lock_parent_ip(void)
 838{
 839        unsigned long addr = CALLER_ADDR0;
 840
 841        if (!in_lock_functions(addr))
 842                return addr;
 843        addr = CALLER_ADDR1;
 844        if (!in_lock_functions(addr))
 845                return addr;
 846        return CALLER_ADDR2;
 847}
 848
 849#ifdef CONFIG_TRACE_PREEMPT_TOGGLE
 850  extern void trace_preempt_on(unsigned long a0, unsigned long a1);
 851  extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 852#else
 853/*
 854 * Use defines instead of static inlines because some arches will make code out
 855 * of the CALLER_ADDR, when we really want these to be a real nop.
 856 */
 857# define trace_preempt_on(a0, a1) do { } while (0)
 858# define trace_preempt_off(a0, a1) do { } while (0)
 859#endif
 860
 861#ifdef CONFIG_FTRACE_MCOUNT_RECORD
 862extern void ftrace_init(void);
 863#ifdef CC_USING_PATCHABLE_FUNCTION_ENTRY
 864#define FTRACE_CALLSITE_SECTION "__patchable_function_entries"
 865#else
 866#define FTRACE_CALLSITE_SECTION "__mcount_loc"
 867#endif
 868#else
 869static inline void ftrace_init(void) { }
 870#endif
 871
 872/*
 873 * Structure that defines an entry function trace.
 874 * It's already packed but the attribute "packed" is needed
 875 * to remove extra padding at the end.
 876 */
 877struct ftrace_graph_ent {
 878        unsigned long func; /* Current function */
 879        int depth;
 880} __packed;
 881
 882/*
 883 * Structure that defines a return function trace.
 884 * It's already packed but the attribute "packed" is needed
 885 * to remove extra padding at the end.
 886 */
 887struct ftrace_graph_ret {
 888        unsigned long func; /* Current function */
 889        int depth;
 890        /* Number of functions that overran the depth limit for current task */
 891        unsigned int overrun;
 892        unsigned long long calltime;
 893        unsigned long long rettime;
 894} __packed;
 895
 896/* Type of the callback handlers for tracing function graph*/
 897typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
 898typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
 899
 900extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace);
 901
 902#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 903
 904struct fgraph_ops {
 905        trace_func_graph_ent_t          entryfunc;
 906        trace_func_graph_ret_t          retfunc;
 907};
 908
 909/*
 910 * Stack of return addresses for functions
 911 * of a thread.
 912 * Used in struct thread_info
 913 */
 914struct ftrace_ret_stack {
 915        unsigned long ret;
 916        unsigned long func;
 917        unsigned long long calltime;
 918#ifdef CONFIG_FUNCTION_PROFILER
 919        unsigned long long subtime;
 920#endif
 921#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
 922        unsigned long fp;
 923#endif
 924#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
 925        unsigned long *retp;
 926#endif
 927};
 928
 929/*
 930 * Primary handler of a function return.
 931 * It relays on ftrace_return_to_handler.
 932 * Defined in entry_32/64.S
 933 */
 934extern void return_to_handler(void);
 935
 936extern int
 937function_graph_enter(unsigned long ret, unsigned long func,
 938                     unsigned long frame_pointer, unsigned long *retp);
 939
 940struct ftrace_ret_stack *
 941ftrace_graph_get_ret_stack(struct task_struct *task, int idx);
 942
 943unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
 944                                    unsigned long ret, unsigned long *retp);
 945
 946/*
 947 * Sometimes we don't want to trace a function with the function
 948 * graph tracer but we want them to keep traced by the usual function
 949 * tracer if the function graph tracer is not configured.
 950 */
 951#define __notrace_funcgraph             notrace
 952
 953#define FTRACE_RETFUNC_DEPTH 50
 954#define FTRACE_RETSTACK_ALLOC_SIZE 32
 955
 956extern int register_ftrace_graph(struct fgraph_ops *ops);
 957extern void unregister_ftrace_graph(struct fgraph_ops *ops);
 958
 959extern bool ftrace_graph_is_dead(void);
 960extern void ftrace_graph_stop(void);
 961
 962/* The current handlers in use */
 963extern trace_func_graph_ret_t ftrace_graph_return;
 964extern trace_func_graph_ent_t ftrace_graph_entry;
 965
 966extern void ftrace_graph_init_task(struct task_struct *t);
 967extern void ftrace_graph_exit_task(struct task_struct *t);
 968extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
 969
 970static inline void pause_graph_tracing(void)
 971{
 972        atomic_inc(&current->tracing_graph_pause);
 973}
 974
 975static inline void unpause_graph_tracing(void)
 976{
 977        atomic_dec(&current->tracing_graph_pause);
 978}
 979#else /* !CONFIG_FUNCTION_GRAPH_TRACER */
 980
 981#define __notrace_funcgraph
 982
 983static inline void ftrace_graph_init_task(struct task_struct *t) { }
 984static inline void ftrace_graph_exit_task(struct task_struct *t) { }
 985static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
 986
 987/* Define as macros as fgraph_ops may not be defined */
 988#define register_ftrace_graph(ops) ({ -1; })
 989#define unregister_ftrace_graph(ops) do { } while (0)
 990
 991static inline unsigned long
 992ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret,
 993                      unsigned long *retp)
 994{
 995        return ret;
 996}
 997
 998static inline void pause_graph_tracing(void) { }
 999static inline void unpause_graph_tracing(void) { }
1000#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1001
1002#ifdef CONFIG_TRACING
1003
1004/* flags for current->trace */
1005enum {
1006        TSK_TRACE_FL_TRACE_BIT  = 0,
1007        TSK_TRACE_FL_GRAPH_BIT  = 1,
1008};
1009enum {
1010        TSK_TRACE_FL_TRACE      = 1 << TSK_TRACE_FL_TRACE_BIT,
1011        TSK_TRACE_FL_GRAPH      = 1 << TSK_TRACE_FL_GRAPH_BIT,
1012};
1013
1014static inline void set_tsk_trace_trace(struct task_struct *tsk)
1015{
1016        set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
1017}
1018
1019static inline void clear_tsk_trace_trace(struct task_struct *tsk)
1020{
1021        clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
1022}
1023
1024static inline int test_tsk_trace_trace(struct task_struct *tsk)
1025{
1026        return tsk->trace & TSK_TRACE_FL_TRACE;
1027}
1028
1029static inline void set_tsk_trace_graph(struct task_struct *tsk)
1030{
1031        set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
1032}
1033
1034static inline void clear_tsk_trace_graph(struct task_struct *tsk)
1035{
1036        clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
1037}
1038
1039static inline int test_tsk_trace_graph(struct task_struct *tsk)
1040{
1041        return tsk->trace & TSK_TRACE_FL_GRAPH;
1042}
1043
1044enum ftrace_dump_mode;
1045
1046extern enum ftrace_dump_mode ftrace_dump_on_oops;
1047extern int tracepoint_printk;
1048
1049extern void disable_trace_on_warning(void);
1050extern int __disable_trace_on_warning;
1051
1052int tracepoint_printk_sysctl(struct ctl_table *table, int write,
1053                             void *buffer, size_t *lenp, loff_t *ppos);
1054
1055#else /* CONFIG_TRACING */
1056static inline void  disable_trace_on_warning(void) { }
1057#endif /* CONFIG_TRACING */
1058
1059#ifdef CONFIG_FTRACE_SYSCALLS
1060
1061unsigned long arch_syscall_addr(int nr);
1062
1063#endif /* CONFIG_FTRACE_SYSCALLS */
1064
1065#endif /* _LINUX_FTRACE_H */
1066