include/linux/ftrace.h

   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.txt
   5  */
   6
   7 #ifndef _LINUX_FTRACE_H
   8 #define _LINUX_FTRACE_H
   9
  10 #include <linux/trace_clock.h>
  11 #include <linux/kallsyms.h>
  12 #include <linux/linkage.h>
  13 #include <linux/bitops.h>
  14 #include <linux/ptrace.h>
  15 #include <linux/ktime.h>
  16 #include <linux/sched.h>
  17 #include <linux/types.h>
  18 #include <linux/init.h>
  19 #include <linux/fs.h>
  20
  21 #include <asm/ftrace.h>
  22
  23 /*
  24  * If the arch supports passing the variable contents of
  25  * function_trace_op as the third parameter back from the
  26  * mcount call, then the arch should define this as 1.
  27  */
  28 #ifndef ARCH_SUPPORTS_FTRACE_OPS
  29 #define ARCH_SUPPORTS_FTRACE_OPS 0
  30 #endif
  31
  32 /*
  33  * If the arch's mcount caller does not support all of ftrace's
  34  * features, then it must call an indirect function that
  35  * does. Or at least does enough to prevent any unwelcomed side effects.
  36  */
  37 #if !ARCH_SUPPORTS_FTRACE_OPS
  38 # define FTRACE_FORCE_LIST_FUNC 1
  39 #else
  40 # define FTRACE_FORCE_LIST_FUNC 0
  41 #endif
  42
  43 /* Main tracing buffer and events set up */
  44 #ifdef CONFIG_TRACING
  45 void trace_init(void);
  46 void early_trace_init(void);
  47 #else
  48 static inline void trace_init(void) { }
  49 static inline void early_trace_init(void) { }
  50 #endif
  51
  52 struct module;
  53 struct ftrace_hash;
  54
  55 #if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_MODULES) && \
  56         defined(CONFIG_DYNAMIC_FTRACE)
  57 const char *
  58 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
  59                    unsigned long *off, char **modname, char *sym);
  60 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
  61                            char *type, char *name,
  62                            char *module_name, int *exported);
  63 #else
  64 static inline const char *
  65 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
  66                    unsigned long *off, char **modname, char *sym)
  67 {
  68         return NULL;
  69 }
  70 static inline int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
  71                                          char *type, char *name,
  72                                          char *module_name, int *exported)
  73 {
  74         return -1;
  75 }
  76 #endif
  77
  78
  79 #ifdef CONFIG_FUNCTION_TRACER
  80
  81 extern int ftrace_enabled;
  82 extern int
  83 ftrace_enable_sysctl(struct ctl_table *table, int write,
  84                      void __user *buffer, size_t *lenp,
  85                      loff_t *ppos);
  86
  87 struct ftrace_ops;
  88
  89 typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
  90                               struct ftrace_ops *op, struct pt_regs *regs);
  91
  92 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops);
  93
  94 /*
  95  * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are
  96  * set in the flags member.
  97  * CONTROL, SAVE_REGS, SAVE_REGS_IF_SUPPORTED, RECURSION_SAFE, STUB and
  98  * IPMODIFY are a kind of attribute flags which can be set only before
  99  * registering the ftrace_ops, and can not be modified while registered.
 100  * Changing those attribute flags after registering ftrace_ops will
 101  * cause unexpected results.
 102  *
 103  * ENABLED - set/unset when ftrace_ops is registered/unregistered
 104  * DYNAMIC - set when ftrace_ops is registered to denote dynamically
 105  *           allocated ftrace_ops which need special care
 106  * SAVE_REGS - The ftrace_ops wants regs saved at each function called
 107  *            and passed to the callback. If this flag is set, but the
 108  *            architecture does not support passing regs
 109  *            (CONFIG_DYNAMIC_FTRACE_WITH_REGS is not defined), then the
 110  *            ftrace_ops will fail to register, unless the next flag
 111  *            is set.
 112  * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the
 113  *            handler can handle an arch that does not save regs
 114  *            (the handler tests if regs == NULL), then it can set
 115  *            this flag instead. It will not fail registering the ftrace_ops
 116  *            but, the regs field will be NULL if the arch does not support
 117  *            passing regs to the handler.
 118  *            Note, if this flag is set, the SAVE_REGS flag will automatically
 119  *            get set upon registering the ftrace_ops, if the arch supports it.
 120  * RECURSION_SAFE - The ftrace_ops can set this to tell the ftrace infrastructure
 121  *            that the call back has its own recursion protection. If it does
 122  *            not set this, then the ftrace infrastructure will add recursion
 123  *            protection for the caller.
 124  * STUB   - The ftrace_ops is just a place holder.
 125  * INITIALIZED - The ftrace_ops has already been initialized (first use time
 126  *            register_ftrace_function() is called, it will initialized the ops)
 127  * DELETED - The ops are being deleted, do not let them be registered again.
 128  * ADDING  - The ops is in the process of being added.
 129  * REMOVING - The ops is in the process of being removed.
 130  * MODIFYING - The ops is in the process of changing its filter functions.
 131  * ALLOC_TRAMP - A dynamic trampoline was allocated by the core code.
 132  *            The arch specific code sets this flag when it allocated a
 133  *            trampoline. This lets the arch know that it can update the
 134  *            trampoline in case the callback function changes.
 135  *            The ftrace_ops trampoline can be set by the ftrace users, and
 136  *            in such cases the arch must not modify it. Only the arch ftrace
 137  *            core code should set this flag.
 138  * IPMODIFY - The ops can modify the IP register. This can only be set with
 139  *            SAVE_REGS. If another ops with this flag set is already registered
 140  *            for any of the functions that this ops will be registered for, then
 141  *            this ops will fail to register or set_filter_ip.
 142  * PID     - Is affected by set_ftrace_pid (allows filtering on those pids)
 143  * RCU     - Set when the ops can only be called when RCU is watching.
 144  * TRACE_ARRAY - The ops->private points to a trace_array descriptor.
 145  */
 146 enum {
 147         FTRACE_OPS_FL_ENABLED                   = 1 << 0,
 148         FTRACE_OPS_FL_DYNAMIC                   = 1 << 1,
 149         FTRACE_OPS_FL_SAVE_REGS                 = 1 << 2,
 150         FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED    = 1 << 3,
 151         FTRACE_OPS_FL_RECURSION_SAFE            = 1 << 4,
 152         FTRACE_OPS_FL_STUB                      = 1 << 5,
 153         FTRACE_OPS_FL_INITIALIZED               = 1 << 6,
 154         FTRACE_OPS_FL_DELETED                   = 1 << 7,
 155         FTRACE_OPS_FL_ADDING                    = 1 << 8,
 156         FTRACE_OPS_FL_REMOVING                  = 1 << 9,
 157         FTRACE_OPS_FL_MODIFYING                 = 1 << 10,
 158         FTRACE_OPS_FL_ALLOC_TRAMP               = 1 << 11,
 159         FTRACE_OPS_FL_IPMODIFY                  = 1 << 12,
 160         FTRACE_OPS_FL_PID                       = 1 << 13,
 161         FTRACE_OPS_FL_RCU                       = 1 << 14,
 162         FTRACE_OPS_FL_TRACE_ARRAY               = 1 << 15,
 163 };
 164
 165 #ifdef CONFIG_DYNAMIC_FTRACE
 166 /* The hash used to know what functions callbacks trace */
 167 struct ftrace_ops_hash {
 168         struct ftrace_hash __rcu        *notrace_hash;
 169         struct ftrace_hash __rcu        *filter_hash;
 170         struct mutex                    regex_lock;
 171 };
 172
 173 void ftrace_free_init_mem(void);
 174 void ftrace_free_mem(struct module *mod, void *start, void *end);
 175 #else
 176 static inline void ftrace_free_init_mem(void) { }
 177 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }
 178 #endif
 179
 180 /*
 181  * Note, ftrace_ops can be referenced outside of RCU protection, unless
 182  * the RCU flag is set. If ftrace_ops is allocated and not part of kernel
 183  * core data, the unregistering of it will perform a scheduling on all CPUs
 184  * to make sure that there are no more users. Depending on the load of the
 185  * system that may take a bit of time.
 186  *
 187  * Any private data added must also take care not to be freed and if private
 188  * data is added to a ftrace_ops that is in core code, the user of the
 189  * ftrace_ops must perform a schedule_on_each_cpu() before freeing it.
 190  */
 191 struct ftrace_ops {
 192         ftrace_func_t                   func;
 193         struct ftrace_ops __rcu         *next;
 194         unsigned long                   flags;
 195         void                            *private;
 196         ftrace_func_t                   saved_func;
 197 #ifdef CONFIG_DYNAMIC_FTRACE
 198         struct ftrace_ops_hash          local_hash;
 199         struct ftrace_ops_hash          *func_hash;
 200         struct ftrace_ops_hash          old_hash;
 201         unsigned long                   trampoline;
 202         unsigned long                   trampoline_size;
 203 #endif
 204 };
 205
 206 /*
 207  * Type of the current tracing.
 208  */
 209 enum ftrace_tracing_type_t {
 210         FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
 211         FTRACE_TYPE_RETURN,     /* Hook the return of the function */
 212 };
 213
 214 /* Current tracing type, default is FTRACE_TYPE_ENTER */
 215 extern enum ftrace_tracing_type_t ftrace_tracing_type;
 216
 217 /*
 218  * The ftrace_ops must be a static and should also
 219  * be read_mostly.  These functions do modify read_mostly variables
 220  * so use them sparely. Never free an ftrace_op or modify the
 221  * next pointer after it has been registered. Even after unregistering
 222  * it, the next pointer may still be used internally.
 223  */
 224 int register_ftrace_function(struct ftrace_ops *ops);
 225 int unregister_ftrace_function(struct ftrace_ops *ops);
 226 void clear_ftrace_function(void);
 227
 228 extern void ftrace_stub(unsigned long a0, unsigned long a1,
 229                         struct ftrace_ops *op, struct pt_regs *regs);
 230
 231 #else /* !CONFIG_FUNCTION_TRACER */
 232 /*
 233  * (un)register_ftrace_function must be a macro since the ops parameter
 234  * must not be evaluated.
 235  */
 236 #define register_ftrace_function(ops) ({ 0; })
 237 #define unregister_ftrace_function(ops) ({ 0; })
 238 static inline int ftrace_nr_registered_ops(void)
 239 {
 240         return 0;
 241 }
 242 static inline void clear_ftrace_function(void) { }
 243 static inline void ftrace_kill(void) { }
 244 static inline void ftrace_free_init_mem(void) { }
 245 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }
 246 #endif /* CONFIG_FUNCTION_TRACER */
 247
 248 #ifdef CONFIG_STACK_TRACER
 249
 250 #define STACK_TRACE_ENTRIES 500
 251
 252 struct stack_trace;
 253
 254 extern unsigned stack_trace_index[];
 255 extern struct stack_trace stack_trace_max;
 256 extern unsigned long stack_trace_max_size;
 257 extern arch_spinlock_t stack_trace_max_lock;
 258
 259 extern int stack_tracer_enabled;
 260 void stack_trace_print(void);
 261 int
 262 stack_trace_sysctl(struct ctl_table *table, int write,
 263                    void __user *buffer, size_t *lenp,
 264                    loff_t *ppos);
 265
 266 /* DO NOT MODIFY THIS VARIABLE DIRECTLY! */
 267 DECLARE_PER_CPU(int, disable_stack_tracer);
 268
 269 /**
 270  * stack_tracer_disable - temporarily disable the stack tracer
 271  *
 272  * There's a few locations (namely in RCU) where stack tracing
 273  * cannot be executed. This function is used to disable stack
 274  * tracing during those critical sections.
 275  *
 276  * This function must be called with preemption or interrupts
 277  * disabled and stack_tracer_enable() must be called shortly after
 278  * while preemption or interrupts are still disabled.
 279  */
 280 static inline void stack_tracer_disable(void)
 281 {
 282         /* Preemption or interupts must be disabled */
 283         if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
 284                 WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
 285         this_cpu_inc(disable_stack_tracer);
 286 }
 287
 288 /**
 289  * stack_tracer_enable - re-enable the stack tracer
 290  *
 291  * After stack_tracer_disable() is called, stack_tracer_enable()
 292  * must be called shortly afterward.
 293  */
 294 static inline void stack_tracer_enable(void)
 295 {
 296         if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
 297                 WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
 298         this_cpu_dec(disable_stack_tracer);
 299 }
 300 #else
 301 static inline void stack_tracer_disable(void) { }
 302 static inline void stack_tracer_enable(void) { }
 303 #endif
 304
 305 #ifdef CONFIG_DYNAMIC_FTRACE
 306
 307 int ftrace_arch_code_modify_prepare(void);
 308 int ftrace_arch_code_modify_post_process(void);
 309
 310 struct dyn_ftrace;
 311
 312 enum ftrace_bug_type {
 313         FTRACE_BUG_UNKNOWN,
 314         FTRACE_BUG_INIT,
 315         FTRACE_BUG_NOP,
 316         FTRACE_BUG_CALL,
 317         FTRACE_BUG_UPDATE,
 318 };
 319 extern enum ftrace_bug_type ftrace_bug_type;
 320
 321 /*
 322  * Archs can set this to point to a variable that holds the value that was
 323  * expected at the call site before calling ftrace_bug().
 324  */
 325 extern const void *ftrace_expected;
 326
 327 void ftrace_bug(int err, struct dyn_ftrace *rec);
 328
 329 struct seq_file;
 330
 331 extern int ftrace_text_reserved(const void *start, const void *end);
 332
 333 extern int ftrace_nr_registered_ops(void);
 334
 335 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr);
 336
 337 bool is_ftrace_trampoline(unsigned long addr);
 338
 339 /*
 340  * The dyn_ftrace record's flags field is split into two parts.
 341  * the first part which is '0-FTRACE_REF_MAX' is a counter of
 342  * the number of callbacks that have registered the function that
 343  * the dyn_ftrace descriptor represents.
 344  *
 345  * The second part is a mask:
 346  *  ENABLED - the function is being traced
 347  *  REGS    - the record wants the function to save regs
 348  *  REGS_EN - the function is set up to save regs.
 349  *  IPMODIFY - the record allows for the IP address to be changed.
 350  *  DISABLED - the record is not ready to be touched yet
 351  *
 352  * When a new ftrace_ops is registered and wants a function to save
 353  * pt_regs, the rec->flag REGS is set. When the function has been
 354  * set up to save regs, the REG_EN flag is set. Once a function
 355  * starts saving regs it will do so until all ftrace_ops are removed
 356  * from tracing that function.
 357  */
 358 enum {
 359         FTRACE_FL_ENABLED       = (1UL << 31),
 360         FTRACE_FL_REGS          = (1UL << 30),
 361         FTRACE_FL_REGS_EN       = (1UL << 29),
 362         FTRACE_FL_TRAMP         = (1UL << 28),
 363         FTRACE_FL_TRAMP_EN      = (1UL << 27),
 364         FTRACE_FL_IPMODIFY      = (1UL << 26),
 365         FTRACE_FL_DISABLED      = (1UL << 25),
 366 };
 367
 368 #define FTRACE_REF_MAX_SHIFT    25
 369 #define FTRACE_FL_BITS          7
 370 #define FTRACE_FL_MASKED_BITS   ((1UL << FTRACE_FL_BITS) - 1)
 371 #define FTRACE_FL_MASK          (FTRACE_FL_MASKED_BITS << FTRACE_REF_MAX_SHIFT)
 372 #define FTRACE_REF_MAX          ((1UL << FTRACE_REF_MAX_SHIFT) - 1)
 373
 374 #define ftrace_rec_count(rec)   ((rec)->flags & ~FTRACE_FL_MASK)
 375
 376 struct dyn_ftrace {
 377         unsigned long           ip; /* address of mcount call-site */
 378         unsigned long           flags;
 379         struct dyn_arch_ftrace  arch;
 380 };
 381
 382 int ftrace_force_update(void);
 383 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
 384                          int remove, int reset);
 385 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
 386                        int len, int reset);
 387 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
 388                         int len, int reset);
 389 void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
 390 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
 391 void ftrace_free_filter(struct ftrace_ops *ops);
 392 void ftrace_ops_set_global_filter(struct ftrace_ops *ops);
 393
 394 enum {
 395         FTRACE_UPDATE_CALLS             = (1 << 0),
 396         FTRACE_DISABLE_CALLS            = (1 << 1),
 397         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
 398         FTRACE_START_FUNC_RET           = (1 << 3),
 399         FTRACE_STOP_FUNC_RET            = (1 << 4),
 400 };
 401
 402 /*
 403  * The FTRACE_UPDATE_* enum is used to pass information back
 404  * from the ftrace_update_record() and ftrace_test_record()
 405  * functions. These are called by the code update routines
 406  * to find out what is to be done for a given function.
 407  *
 408  *  IGNORE           - The function is already what we want it to be
 409  *  MAKE_CALL        - Start tracing the function
 410  *  MODIFY_CALL      - Stop saving regs for the function
 411  *  MAKE_NOP         - Stop tracing the function
 412  */
 413 enum {
 414         FTRACE_UPDATE_IGNORE,
 415         FTRACE_UPDATE_MAKE_CALL,
 416         FTRACE_UPDATE_MODIFY_CALL,
 417         FTRACE_UPDATE_MAKE_NOP,
 418 };
 419
 420 enum {
 421         FTRACE_ITER_FILTER      = (1 << 0),
 422         FTRACE_ITER_NOTRACE     = (1 << 1),
 423         FTRACE_ITER_PRINTALL    = (1 << 2),
 424         FTRACE_ITER_DO_PROBES   = (1 << 3),
 425         FTRACE_ITER_PROBE       = (1 << 4),
 426         FTRACE_ITER_MOD         = (1 << 5),
 427         FTRACE_ITER_ENABLED     = (1 << 6),
 428 };
 429
 430 void arch_ftrace_update_code(int command);
 431
 432 struct ftrace_rec_iter;
 433
 434 struct ftrace_rec_iter *ftrace_rec_iter_start(void);
 435 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
 436 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);
 437
 438 #define for_ftrace_rec_iter(iter)               \
 439         for (iter = ftrace_rec_iter_start();    \
 440              iter;                              \
 441              iter = ftrace_rec_iter_next(iter))
 442
 443
 444 int ftrace_update_record(struct dyn_ftrace *rec, int enable);
 445 int ftrace_test_record(struct dyn_ftrace *rec, int enable);
 446 void ftrace_run_stop_machine(int command);
 447 unsigned long ftrace_location(unsigned long ip);
 448 unsigned long ftrace_location_range(unsigned long start, unsigned long end);
 449 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec);
 450 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec);
 451
 452 extern ftrace_func_t ftrace_trace_function;
 453
 454 int ftrace_regex_open(struct ftrace_ops *ops, int flag,
 455                   struct inode *inode, struct file *file);
 456 ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 457                             size_t cnt, loff_t *ppos);
 458 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 459                              size_t cnt, loff_t *ppos);
 460 int ftrace_regex_release(struct inode *inode, struct file *file);
 461
 462 void __init
 463 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
 464
 465 /* defined in arch */
 466 extern int ftrace_ip_converted(unsigned long ip);
 467 extern int ftrace_dyn_arch_init(void);
 468 extern void ftrace_replace_code(int enable);
 469 extern int ftrace_update_ftrace_func(ftrace_func_t func);
 470 extern void ftrace_caller(void);
 471 extern void ftrace_regs_caller(void);
 472 extern void ftrace_call(void);
 473 extern void ftrace_regs_call(void);
 474 extern void mcount_call(void);
 475
 476 void ftrace_modify_all_code(int command);
 477
 478 #ifndef FTRACE_ADDR
 479 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
 480 #endif
 481
 482 #ifndef FTRACE_GRAPH_ADDR
 483 #define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller)
 484 #endif
 485
 486 #ifndef FTRACE_REGS_ADDR
 487 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 488 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller)
 489 #else
 490 # define FTRACE_REGS_ADDR FTRACE_ADDR
 491 #endif
 492 #endif
 493
 494 /*
 495  * If an arch would like functions that are only traced
 496  * by the function graph tracer to jump directly to its own
 497  * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR
 498  * to be that address to jump to.
 499  */
 500 #ifndef FTRACE_GRAPH_TRAMP_ADDR
 501 #define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0)
 502 #endif
 503
 504 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 505 extern void ftrace_graph_caller(void);
 506 extern int ftrace_enable_ftrace_graph_caller(void);
 507 extern int ftrace_disable_ftrace_graph_caller(void);
 508 #else
 509 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
 510 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
 511 #endif
 512
 513 /**
 514  * ftrace_make_nop - convert code into nop
 515  * @mod: module structure if called by module load initialization
 516  * @rec: the mcount call site record
 517  * @addr: the address that the call site should be calling
 518  *
 519  * This is a very sensitive operation and great care needs
 520  * to be taken by the arch.  The operation should carefully
 521  * read the location, check to see if what is read is indeed
 522  * what we expect it to be, and then on success of the compare,
 523  * it should write to the location.
 524  *
 525  * The code segment at @rec->ip should be a caller to @addr
 526  *
 527  * Return must be:
 528  *  0 on success
 529  *  -EFAULT on error reading the location
 530  *  -EINVAL on a failed compare of the contents
 531  *  -EPERM  on error writing to the location
 532  * Any other value will be considered a failure.
 533  */
 534 extern int ftrace_make_nop(struct module *mod,
 535                            struct dyn_ftrace *rec, unsigned long addr);
 536
 537 /**
 538  * ftrace_make_call - convert a nop call site into a call to addr
 539  * @rec: the mcount call site record
 540  * @addr: the address that the call site should call
 541  *
 542  * This is a very sensitive operation and great care needs
 543  * to be taken by the arch.  The operation should carefully
 544  * read the location, check to see if what is read is indeed
 545  * what we expect it to be, and then on success of the compare,
 546  * it should write to the location.
 547  *
 548  * The code segment at @rec->ip should be a nop
 549  *
 550  * Return must be:
 551  *  0 on success
 552  *  -EFAULT on error reading the location
 553  *  -EINVAL on a failed compare of the contents
 554  *  -EPERM  on error writing to the location
 555  * Any other value will be considered a failure.
 556  */
 557 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
 558
 559 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 560 /**
 561  * ftrace_modify_call - convert from one addr to another (no nop)
 562  * @rec: the mcount call site record
 563  * @old_addr: the address expected to be currently called to
 564  * @addr: the address to change to
 565  *
 566  * This is a very sensitive operation and great care needs
 567  * to be taken by the arch.  The operation should carefully
 568  * read the location, check to see if what is read is indeed
 569  * what we expect it to be, and then on success of the compare,
 570  * it should write to the location.
 571  *
 572  * The code segment at @rec->ip should be a caller to @old_addr
 573  *
 574  * Return must be:
 575  *  0 on success
 576  *  -EFAULT on error reading the location
 577  *  -EINVAL on a failed compare of the contents
 578  *  -EPERM  on error writing to the location
 579  * Any other value will be considered a failure.
 580  */
 581 extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 582                               unsigned long addr);
 583 #else
 584 /* Should never be called */
 585 static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 586                                      unsigned long addr)
 587 {
 588         return -EINVAL;
 589 }
 590 #endif
 591
 592 /* May be defined in arch */
 593 extern int ftrace_arch_read_dyn_info(char *buf, int size);
 594
 595 extern int skip_trace(unsigned long ip);
 596 extern void ftrace_module_init(struct module *mod);
 597 extern void ftrace_module_enable(struct module *mod);
 598 extern void ftrace_release_mod(struct module *mod);
 599
 600 extern void ftrace_disable_daemon(void);
 601 extern void ftrace_enable_daemon(void);
 602 #else /* CONFIG_DYNAMIC_FTRACE */
 603 static inline int skip_trace(unsigned long ip) { return 0; }
 604 static inline int ftrace_force_update(void) { return 0; }
 605 static inline void ftrace_disable_daemon(void) { }
 606 static inline void ftrace_enable_daemon(void) { }
 607 static inline void ftrace_module_init(struct module *mod) { }
 608 static inline void ftrace_module_enable(struct module *mod) { }
 609 static inline void ftrace_release_mod(struct module *mod) { }
 610 static inline int ftrace_text_reserved(const void *start, const void *end)
 611 {
 612         return 0;
 613 }
 614 static inline unsigned long ftrace_location(unsigned long ip)
 615 {
 616         return 0;
 617 }
 618
 619 /*
 620  * Again users of functions that have ftrace_ops may not
 621  * have them defined when ftrace is not enabled, but these
 622  * functions may still be called. Use a macro instead of inline.
 623  */
 624 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
 625 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
 626 #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; })
 627 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
 628 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
 629 #define ftrace_free_filter(ops) do { } while (0)
 630 #define ftrace_ops_set_global_filter(ops) do { } while (0)
 631
 632 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 633                             size_t cnt, loff_t *ppos) { return -ENODEV; }
 634 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 635                              size_t cnt, loff_t *ppos) { return -ENODEV; }
 636 static inline int
 637 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
 638
 639 static inline bool is_ftrace_trampoline(unsigned long addr)
 640 {
 641         return false;
 642 }
 643 #endif /* CONFIG_DYNAMIC_FTRACE */
 644
 645 /* totally disable ftrace - can not re-enable after this */
 646 void ftrace_kill(void);
 647
 648 static inline void tracer_disable(void)
 649 {
 650 #ifdef CONFIG_FUNCTION_TRACER
 651         ftrace_enabled = 0;
 652 #endif
 653 }
 654
 655 /*
 656  * Ftrace disable/restore without lock. Some synchronization mechanism
 657  * must be used to prevent ftrace_enabled to be changed between
 658  * disable/restore.
 659  */
 660 static inline int __ftrace_enabled_save(void)
 661 {
 662 #ifdef CONFIG_FUNCTION_TRACER
 663         int saved_ftrace_enabled = ftrace_enabled;
 664         ftrace_enabled = 0;
 665         return saved_ftrace_enabled;
 666 #else
 667         return 0;
 668 #endif
 669 }
 670
 671 static inline void __ftrace_enabled_restore(int enabled)
 672 {
 673 #ifdef CONFIG_FUNCTION_TRACER
 674         ftrace_enabled = enabled;
 675 #endif
 676 }
 677
 678 /* All archs should have this, but we define it for consistency */
 679 #ifndef ftrace_return_address0
 680 # define ftrace_return_address0 __builtin_return_address(0)
 681 #endif
 682
 683 /* Archs may use other ways for ADDR1 and beyond */
 684 #ifndef ftrace_return_address
 685 # ifdef CONFIG_FRAME_POINTER
 686 #  define ftrace_return_address(n) __builtin_return_address(n)
 687 # else
 688 #  define ftrace_return_address(n) 0UL
 689 # endif
 690 #endif
 691
 692 #define CALLER_ADDR0 ((unsigned long)ftrace_return_address0)
 693 #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1))
 694 #define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2))
 695 #define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3))
 696 #define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4))
 697 #define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5))
 698 #define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6))
 699
 700 static inline unsigned long get_lock_parent_ip(void)
 701 {
 702         unsigned long addr = CALLER_ADDR0;
 703
 704         if (!in_lock_functions(addr))
 705                 return addr;
 706         addr = CALLER_ADDR1;
 707         if (!in_lock_functions(addr))
 708                 return addr;
 709         return CALLER_ADDR2;
 710 }
 711
 712 #ifdef CONFIG_IRQSOFF_TRACER
 713   extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
 714   extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
 715 #else
 716   static inline void time_hardirqs_on(unsigned long a0, unsigned long a1) { }
 717   static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { }
 718 #endif
 719
 720 #if defined(CONFIG_PREEMPT_TRACER) || \
 721         (defined(CONFIG_DEBUG_PREEMPT) && defined(CONFIG_PREEMPTIRQ_EVENTS))
 722   extern void trace_preempt_on(unsigned long a0, unsigned long a1);
 723   extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 724 #else
 725 /*
 726  * Use defines instead of static inlines because some arches will make code out
 727  * of the CALLER_ADDR, when we really want these to be a real nop.
 728  */
 729 # define trace_preempt_on(a0, a1) do { } while (0)
 730 # define trace_preempt_off(a0, a1) do { } while (0)
 731 #endif
 732
 733 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 734 extern void ftrace_init(void);
 735 #else
 736 static inline void ftrace_init(void) { }
 737 #endif
 738
 739 /*
 740  * Structure that defines an entry function trace.
 741  * It's already packed but the attribute "packed" is needed
 742  * to remove extra padding at the end.
 743  */
 744 struct ftrace_graph_ent {
 745         unsigned long func; /* Current function */
 746         int depth;
 747 } __packed;
 748
 749 /*
 750  * Structure that defines a return function trace.
 751  * It's already packed but the attribute "packed" is needed
 752  * to remove extra padding at the end.
 753  */
 754 struct ftrace_graph_ret {
 755         unsigned long func; /* Current function */
 756         /* Number of functions that overran the depth limit for current task */
 757         unsigned long overrun;
 758         unsigned long long calltime;
 759         unsigned long long rettime;
 760         int depth;
 761 } __packed;
 762
 763 /* Type of the callback handlers for tracing function graph*/
 764 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
 765 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
 766
 767 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 768
 769 /* for init task */
 770 #define INIT_FTRACE_GRAPH               .ret_stack = NULL,
 771
 772 /*
 773  * Stack of return addresses for functions
 774  * of a thread.
 775  * Used in struct thread_info
 776  */
 777 struct ftrace_ret_stack {
 778         unsigned long ret;
 779         unsigned long func;
 780         unsigned long long calltime;
 781 #ifdef CONFIG_FUNCTION_PROFILER
 782         unsigned long long subtime;
 783 #endif
 784 #ifdef HAVE_FUNCTION_GRAPH_FP_TEST
 785         unsigned long fp;
 786 #endif
 787 #ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
 788         unsigned long *retp;
 789 #endif
 790 };
 791
 792 /*
 793  * Primary handler of a function return.
 794  * It relays on ftrace_return_to_handler.
 795  * Defined in entry_32/64.S
 796  */
 797 extern void return_to_handler(void);
 798
 799 extern int
 800 function_graph_enter(unsigned long ret, unsigned long func,
 801                      unsigned long frame_pointer, unsigned long *retp);
 802
 803 unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
 804                                     unsigned long ret, unsigned long *retp);
 805
 806 /*
 807  * Sometimes we don't want to trace a function with the function
 808  * graph tracer but we want them to keep traced by the usual function
 809  * tracer if the function graph tracer is not configured.
 810  */
 811 #define __notrace_funcgraph             notrace
 812
 813 #define FTRACE_NOTRACE_DEPTH 65536
 814 #define FTRACE_RETFUNC_DEPTH 50
 815 #define FTRACE_RETSTACK_ALLOC_SIZE 32
 816 extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 817                                 trace_func_graph_ent_t entryfunc);
 818
 819 extern bool ftrace_graph_is_dead(void);
 820 extern void ftrace_graph_stop(void);
 821
 822 /* The current handlers in use */
 823 extern trace_func_graph_ret_t ftrace_graph_return;
 824 extern trace_func_graph_ent_t ftrace_graph_entry;
 825
 826 extern void unregister_ftrace_graph(void);
 827
 828 extern void ftrace_graph_init_task(struct task_struct *t);
 829 extern void ftrace_graph_exit_task(struct task_struct *t);
 830 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
 831
 832 static inline int task_curr_ret_stack(struct task_struct *t)
 833 {
 834         return t->curr_ret_stack;
 835 }
 836
 837 static inline void pause_graph_tracing(void)
 838 {
 839         atomic_inc(&current->tracing_graph_pause);
 840 }
 841
 842 static inline void unpause_graph_tracing(void)
 843 {
 844         atomic_dec(&current->tracing_graph_pause);
 845 }
 846 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */
 847
 848 #define __notrace_funcgraph
 849 #define INIT_FTRACE_GRAPH
 850
 851 static inline void ftrace_graph_init_task(struct task_struct *t) { }
 852 static inline void ftrace_graph_exit_task(struct task_struct *t) { }
 853 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
 854
 855 static inline int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 856                           trace_func_graph_ent_t entryfunc)
 857 {
 858         return -1;
 859 }
 860 static inline void unregister_ftrace_graph(void) { }
 861
 862 static inline int task_curr_ret_stack(struct task_struct *tsk)
 863 {
 864         return -1;
 865 }
 866
 867 static inline unsigned long
 868 ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret,
 869                       unsigned long *retp)
 870 {
 871         return ret;
 872 }
 873
 874 static inline void pause_graph_tracing(void) { }
 875 static inline void unpause_graph_tracing(void) { }
 876 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 877
 878 #ifdef CONFIG_TRACING
 879
 880 /* flags for current->trace */
 881 enum {
 882         TSK_TRACE_FL_TRACE_BIT  = 0,
 883         TSK_TRACE_FL_GRAPH_BIT  = 1,
 884 };
 885 enum {
 886         TSK_TRACE_FL_TRACE      = 1 << TSK_TRACE_FL_TRACE_BIT,
 887         TSK_TRACE_FL_GRAPH      = 1 << TSK_TRACE_FL_GRAPH_BIT,
 888 };
 889
 890 static inline void set_tsk_trace_trace(struct task_struct *tsk)
 891 {
 892         set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 893 }
 894
 895 static inline void clear_tsk_trace_trace(struct task_struct *tsk)
 896 {
 897         clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 898 }
 899
 900 static inline int test_tsk_trace_trace(struct task_struct *tsk)
 901 {
 902         return tsk->trace & TSK_TRACE_FL_TRACE;
 903 }
 904
 905 static inline void set_tsk_trace_graph(struct task_struct *tsk)
 906 {
 907         set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 908 }
 909
 910 static inline void clear_tsk_trace_graph(struct task_struct *tsk)
 911 {
 912         clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 913 }
 914
 915 static inline int test_tsk_trace_graph(struct task_struct *tsk)
 916 {
 917         return tsk->trace & TSK_TRACE_FL_GRAPH;
 918 }
 919
 920 enum ftrace_dump_mode;
 921
 922 extern enum ftrace_dump_mode ftrace_dump_on_oops;
 923 extern int tracepoint_printk;
 924
 925 extern void disable_trace_on_warning(void);
 926 extern int __disable_trace_on_warning;
 927
 928 #ifdef CONFIG_PREEMPT
 929 #define INIT_TRACE_RECURSION            .trace_recursion = 0,
 930 #endif
 931
 932 int tracepoint_printk_sysctl(struct ctl_table *table, int write,
 933                              void __user *buffer, size_t *lenp,
 934                              loff_t *ppos);
 935
 936 #else /* CONFIG_TRACING */
 937 static inline void  disable_trace_on_warning(void) { }
 938 #endif /* CONFIG_TRACING */
 939
 940 #ifndef INIT_TRACE_RECURSION
 941 #define INIT_TRACE_RECURSION
 942 #endif
 943
 944 #ifdef CONFIG_FTRACE_SYSCALLS
 945
 946 unsigned long arch_syscall_addr(int nr);
 947
 948 #endif /* CONFIG_FTRACE_SYSCALLS */
 949
 950 #endif /* _LINUX_FTRACE_H */