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 bool is_ftrace_trampoline(unsigned long addr);
 336
 337 /*
 338  * The dyn_ftrace record's flags field is split into two parts.
 339  * the first part which is '0-FTRACE_REF_MAX' is a counter of
 340  * the number of callbacks that have registered the function that
 341  * the dyn_ftrace descriptor represents.
 342  *
 343  * The second part is a mask:
 344  *  ENABLED - the function is being traced
 345  *  REGS    - the record wants the function to save regs
 346  *  REGS_EN - the function is set up to save regs.
 347  *  IPMODIFY - the record allows for the IP address to be changed.
 348  *  DISABLED - the record is not ready to be touched yet
 349  *
 350  * When a new ftrace_ops is registered and wants a function to save
 351  * pt_regs, the rec->flag REGS is set. When the function has been
 352  * set up to save regs, the REG_EN flag is set. Once a function
 353  * starts saving regs it will do so until all ftrace_ops are removed
 354  * from tracing that function.
 355  */
 356 enum {
 357         FTRACE_FL_ENABLED       = (1UL << 31),
 358         FTRACE_FL_REGS          = (1UL << 30),
 359         FTRACE_FL_REGS_EN       = (1UL << 29),
 360         FTRACE_FL_TRAMP         = (1UL << 28),
 361         FTRACE_FL_TRAMP_EN      = (1UL << 27),
 362         FTRACE_FL_IPMODIFY      = (1UL << 26),
 363         FTRACE_FL_DISABLED      = (1UL << 25),
 364 };
 365
 366 #define FTRACE_REF_MAX_SHIFT    25
 367 #define FTRACE_FL_BITS          7
 368 #define FTRACE_FL_MASKED_BITS   ((1UL << FTRACE_FL_BITS) - 1)
 369 #define FTRACE_FL_MASK          (FTRACE_FL_MASKED_BITS << FTRACE_REF_MAX_SHIFT)
 370 #define FTRACE_REF_MAX          ((1UL << FTRACE_REF_MAX_SHIFT) - 1)
 371
 372 #define ftrace_rec_count(rec)   ((rec)->flags & ~FTRACE_FL_MASK)
 373
 374 struct dyn_ftrace {
 375         unsigned long           ip; /* address of mcount call-site */
 376         unsigned long           flags;
 377         struct dyn_arch_ftrace  arch;
 378 };
 379
 380 int ftrace_force_update(void);
 381 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
 382                          int remove, int reset);
 383 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
 384                        int len, int reset);
 385 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
 386                         int len, int reset);
 387 void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
 388 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
 389 void ftrace_free_filter(struct ftrace_ops *ops);
 390 void ftrace_ops_set_global_filter(struct ftrace_ops *ops);
 391
 392 enum {
 393         FTRACE_UPDATE_CALLS             = (1 << 0),
 394         FTRACE_DISABLE_CALLS            = (1 << 1),
 395         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
 396         FTRACE_START_FUNC_RET           = (1 << 3),
 397         FTRACE_STOP_FUNC_RET            = (1 << 4),
 398 };
 399
 400 /*
 401  * The FTRACE_UPDATE_* enum is used to pass information back
 402  * from the ftrace_update_record() and ftrace_test_record()
 403  * functions. These are called by the code update routines
 404  * to find out what is to be done for a given function.
 405  *
 406  *  IGNORE           - The function is already what we want it to be
 407  *  MAKE_CALL        - Start tracing the function
 408  *  MODIFY_CALL      - Stop saving regs for the function
 409  *  MAKE_NOP         - Stop tracing the function
 410  */
 411 enum {
 412         FTRACE_UPDATE_IGNORE,
 413         FTRACE_UPDATE_MAKE_CALL,
 414         FTRACE_UPDATE_MODIFY_CALL,
 415         FTRACE_UPDATE_MAKE_NOP,
 416 };
 417
 418 enum {
 419         FTRACE_ITER_FILTER      = (1 << 0),
 420         FTRACE_ITER_NOTRACE     = (1 << 1),
 421         FTRACE_ITER_PRINTALL    = (1 << 2),
 422         FTRACE_ITER_DO_PROBES   = (1 << 3),
 423         FTRACE_ITER_PROBE       = (1 << 4),
 424         FTRACE_ITER_MOD         = (1 << 5),
 425         FTRACE_ITER_ENABLED     = (1 << 6),
 426 };
 427
 428 void arch_ftrace_update_code(int command);
 429
 430 struct ftrace_rec_iter;
 431
 432 struct ftrace_rec_iter *ftrace_rec_iter_start(void);
 433 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
 434 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);
 435
 436 #define for_ftrace_rec_iter(iter)               \
 437         for (iter = ftrace_rec_iter_start();    \
 438              iter;                              \
 439              iter = ftrace_rec_iter_next(iter))
 440
 441
 442 int ftrace_update_record(struct dyn_ftrace *rec, int enable);
 443 int ftrace_test_record(struct dyn_ftrace *rec, int enable);
 444 void ftrace_run_stop_machine(int command);
 445 unsigned long ftrace_location(unsigned long ip);
 446 unsigned long ftrace_location_range(unsigned long start, unsigned long end);
 447 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec);
 448 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec);
 449
 450 extern ftrace_func_t ftrace_trace_function;
 451
 452 int ftrace_regex_open(struct ftrace_ops *ops, int flag,
 453                   struct inode *inode, struct file *file);
 454 ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 455                             size_t cnt, loff_t *ppos);
 456 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 457                              size_t cnt, loff_t *ppos);
 458 int ftrace_regex_release(struct inode *inode, struct file *file);
 459
 460 void __init
 461 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
 462
 463 /* defined in arch */
 464 extern int ftrace_ip_converted(unsigned long ip);
 465 extern int ftrace_dyn_arch_init(void);
 466 extern void ftrace_replace_code(int enable);
 467 extern int ftrace_update_ftrace_func(ftrace_func_t func);
 468 extern void ftrace_caller(void);
 469 extern void ftrace_regs_caller(void);
 470 extern void ftrace_call(void);
 471 extern void ftrace_regs_call(void);
 472 extern void mcount_call(void);
 473
 474 void ftrace_modify_all_code(int command);
 475
 476 #ifndef FTRACE_ADDR
 477 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
 478 #endif
 479
 480 #ifndef FTRACE_GRAPH_ADDR
 481 #define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller)
 482 #endif
 483
 484 #ifndef FTRACE_REGS_ADDR
 485 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 486 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller)
 487 #else
 488 # define FTRACE_REGS_ADDR FTRACE_ADDR
 489 #endif
 490 #endif
 491
 492 /*
 493  * If an arch would like functions that are only traced
 494  * by the function graph tracer to jump directly to its own
 495  * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR
 496  * to be that address to jump to.
 497  */
 498 #ifndef FTRACE_GRAPH_TRAMP_ADDR
 499 #define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0)
 500 #endif
 501
 502 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 503 extern void ftrace_graph_caller(void);
 504 extern int ftrace_enable_ftrace_graph_caller(void);
 505 extern int ftrace_disable_ftrace_graph_caller(void);
 506 #else
 507 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
 508 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
 509 #endif
 510
 511 /**
 512  * ftrace_make_nop - convert code into nop
 513  * @mod: module structure if called by module load initialization
 514  * @rec: the mcount call site record
 515  * @addr: the address that the call site should be calling
 516  *
 517  * This is a very sensitive operation and great care needs
 518  * to be taken by the arch.  The operation should carefully
 519  * read the location, check to see if what is read is indeed
 520  * what we expect it to be, and then on success of the compare,
 521  * it should write to the location.
 522  *
 523  * The code segment at @rec->ip should be a caller to @addr
 524  *
 525  * Return must be:
 526  *  0 on success
 527  *  -EFAULT on error reading the location
 528  *  -EINVAL on a failed compare of the contents
 529  *  -EPERM  on error writing to the location
 530  * Any other value will be considered a failure.
 531  */
 532 extern int ftrace_make_nop(struct module *mod,
 533                            struct dyn_ftrace *rec, unsigned long addr);
 534
 535 /**
 536  * ftrace_make_call - convert a nop call site into a call to addr
 537  * @rec: the mcount call site record
 538  * @addr: the address that the call site should call
 539  *
 540  * This is a very sensitive operation and great care needs
 541  * to be taken by the arch.  The operation should carefully
 542  * read the location, check to see if what is read is indeed
 543  * what we expect it to be, and then on success of the compare,
 544  * it should write to the location.
 545  *
 546  * The code segment at @rec->ip should be a nop
 547  *
 548  * Return must be:
 549  *  0 on success
 550  *  -EFAULT on error reading the location
 551  *  -EINVAL on a failed compare of the contents
 552  *  -EPERM  on error writing to the location
 553  * Any other value will be considered a failure.
 554  */
 555 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
 556
 557 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 558 /**
 559  * ftrace_modify_call - convert from one addr to another (no nop)
 560  * @rec: the mcount call site record
 561  * @old_addr: the address expected to be currently called to
 562  * @addr: the address to change to
 563  *
 564  * This is a very sensitive operation and great care needs
 565  * to be taken by the arch.  The operation should carefully
 566  * read the location, check to see if what is read is indeed
 567  * what we expect it to be, and then on success of the compare,
 568  * it should write to the location.
 569  *
 570  * The code segment at @rec->ip should be a caller to @old_addr
 571  *
 572  * Return must be:
 573  *  0 on success
 574  *  -EFAULT on error reading the location
 575  *  -EINVAL on a failed compare of the contents
 576  *  -EPERM  on error writing to the location
 577  * Any other value will be considered a failure.
 578  */
 579 extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 580                               unsigned long addr);
 581 #else
 582 /* Should never be called */
 583 static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 584                                      unsigned long addr)
 585 {
 586         return -EINVAL;
 587 }
 588 #endif
 589
 590 /* May be defined in arch */
 591 extern int ftrace_arch_read_dyn_info(char *buf, int size);
 592
 593 extern int skip_trace(unsigned long ip);
 594 extern void ftrace_module_init(struct module *mod);
 595 extern void ftrace_module_enable(struct module *mod);
 596 extern void ftrace_release_mod(struct module *mod);
 597
 598 extern void ftrace_disable_daemon(void);
 599 extern void ftrace_enable_daemon(void);
 600 #else /* CONFIG_DYNAMIC_FTRACE */
 601 static inline int skip_trace(unsigned long ip) { return 0; }
 602 static inline int ftrace_force_update(void) { return 0; }
 603 static inline void ftrace_disable_daemon(void) { }
 604 static inline void ftrace_enable_daemon(void) { }
 605 static inline void ftrace_module_init(struct module *mod) { }
 606 static inline void ftrace_module_enable(struct module *mod) { }
 607 static inline void ftrace_release_mod(struct module *mod) { }
 608 static inline int ftrace_text_reserved(const void *start, const void *end)
 609 {
 610         return 0;
 611 }
 612 static inline unsigned long ftrace_location(unsigned long ip)
 613 {
 614         return 0;
 615 }
 616
 617 /*
 618  * Again users of functions that have ftrace_ops may not
 619  * have them defined when ftrace is not enabled, but these
 620  * functions may still be called. Use a macro instead of inline.
 621  */
 622 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
 623 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
 624 #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; })
 625 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
 626 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
 627 #define ftrace_free_filter(ops) do { } while (0)
 628 #define ftrace_ops_set_global_filter(ops) do { } while (0)
 629
 630 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 631                             size_t cnt, loff_t *ppos) { return -ENODEV; }
 632 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 633                              size_t cnt, loff_t *ppos) { return -ENODEV; }
 634 static inline int
 635 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
 636
 637 static inline bool is_ftrace_trampoline(unsigned long addr)
 638 {
 639         return false;
 640 }
 641 #endif /* CONFIG_DYNAMIC_FTRACE */
 642
 643 /* totally disable ftrace - can not re-enable after this */
 644 void ftrace_kill(void);
 645
 646 static inline void tracer_disable(void)
 647 {
 648 #ifdef CONFIG_FUNCTION_TRACER
 649         ftrace_enabled = 0;
 650 #endif
 651 }
 652
 653 /*
 654  * Ftrace disable/restore without lock. Some synchronization mechanism
 655  * must be used to prevent ftrace_enabled to be changed between
 656  * disable/restore.
 657  */
 658 static inline int __ftrace_enabled_save(void)
 659 {
 660 #ifdef CONFIG_FUNCTION_TRACER
 661         int saved_ftrace_enabled = ftrace_enabled;
 662         ftrace_enabled = 0;
 663         return saved_ftrace_enabled;
 664 #else
 665         return 0;
 666 #endif
 667 }
 668
 669 static inline void __ftrace_enabled_restore(int enabled)
 670 {
 671 #ifdef CONFIG_FUNCTION_TRACER
 672         ftrace_enabled = enabled;
 673 #endif
 674 }
 675
 676 /* All archs should have this, but we define it for consistency */
 677 #ifndef ftrace_return_address0
 678 # define ftrace_return_address0 __builtin_return_address(0)
 679 #endif
 680
 681 /* Archs may use other ways for ADDR1 and beyond */
 682 #ifndef ftrace_return_address
 683 # ifdef CONFIG_FRAME_POINTER
 684 #  define ftrace_return_address(n) __builtin_return_address(n)
 685 # else
 686 #  define ftrace_return_address(n) 0UL
 687 # endif
 688 #endif
 689
 690 #define CALLER_ADDR0 ((unsigned long)ftrace_return_address0)
 691 #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1))
 692 #define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2))
 693 #define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3))
 694 #define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4))
 695 #define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5))
 696 #define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6))
 697
 698 static inline unsigned long get_lock_parent_ip(void)
 699 {
 700         unsigned long addr = CALLER_ADDR0;
 701
 702         if (!in_lock_functions(addr))
 703                 return addr;
 704         addr = CALLER_ADDR1;
 705         if (!in_lock_functions(addr))
 706                 return addr;
 707         return CALLER_ADDR2;
 708 }
 709
 710 #ifdef CONFIG_IRQSOFF_TRACER
 711   extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
 712   extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
 713 #else
 714   static inline void time_hardirqs_on(unsigned long a0, unsigned long a1) { }
 715   static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { }
 716 #endif
 717
 718 #if defined(CONFIG_PREEMPT_TRACER) || \
 719         (defined(CONFIG_DEBUG_PREEMPT) && defined(CONFIG_PREEMPTIRQ_EVENTS))
 720   extern void trace_preempt_on(unsigned long a0, unsigned long a1);
 721   extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 722 #else
 723 /*
 724  * Use defines instead of static inlines because some arches will make code out
 725  * of the CALLER_ADDR, when we really want these to be a real nop.
 726  */
 727 # define trace_preempt_on(a0, a1) do { } while (0)
 728 # define trace_preempt_off(a0, a1) do { } while (0)
 729 #endif
 730
 731 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 732 extern void ftrace_init(void);
 733 #else
 734 static inline void ftrace_init(void) { }
 735 #endif
 736
 737 /*
 738  * Structure that defines an entry function trace.
 739  * It's already packed but the attribute "packed" is needed
 740  * to remove extra padding at the end.
 741  */
 742 struct ftrace_graph_ent {
 743         unsigned long func; /* Current function */
 744         int depth;
 745 } __packed;
 746
 747 /*
 748  * Structure that defines a return function trace.
 749  * It's already packed but the attribute "packed" is needed
 750  * to remove extra padding at the end.
 751  */
 752 struct ftrace_graph_ret {
 753         unsigned long func; /* Current function */
 754         /* Number of functions that overran the depth limit for current task */
 755         unsigned long overrun;
 756         unsigned long long calltime;
 757         unsigned long long rettime;
 758         int depth;
 759 } __packed;
 760
 761 /* Type of the callback handlers for tracing function graph*/
 762 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
 763 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
 764
 765 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 766
 767 /* for init task */
 768 #define INIT_FTRACE_GRAPH               .ret_stack = NULL,
 769
 770 /*
 771  * Stack of return addresses for functions
 772  * of a thread.
 773  * Used in struct thread_info
 774  */
 775 struct ftrace_ret_stack {
 776         unsigned long ret;
 777         unsigned long func;
 778         unsigned long long calltime;
 779 #ifdef CONFIG_FUNCTION_PROFILER
 780         unsigned long long subtime;
 781 #endif
 782 #ifdef HAVE_FUNCTION_GRAPH_FP_TEST
 783         unsigned long fp;
 784 #endif
 785 #ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
 786         unsigned long *retp;
 787 #endif
 788 };
 789
 790 /*
 791  * Primary handler of a function return.
 792  * It relays on ftrace_return_to_handler.
 793  * Defined in entry_32/64.S
 794  */
 795 extern void return_to_handler(void);
 796
 797 extern int
 798 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
 799                          unsigned long frame_pointer, unsigned long *retp);
 800
 801 unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
 802                                     unsigned long ret, unsigned long *retp);
 803
 804 /*
 805  * Sometimes we don't want to trace a function with the function
 806  * graph tracer but we want them to keep traced by the usual function
 807  * tracer if the function graph tracer is not configured.
 808  */
 809 #define __notrace_funcgraph             notrace
 810
 811 #define FTRACE_NOTRACE_DEPTH 65536
 812 #define FTRACE_RETFUNC_DEPTH 50
 813 #define FTRACE_RETSTACK_ALLOC_SIZE 32
 814 extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 815                                 trace_func_graph_ent_t entryfunc);
 816
 817 extern bool ftrace_graph_is_dead(void);
 818 extern void ftrace_graph_stop(void);
 819
 820 /* The current handlers in use */
 821 extern trace_func_graph_ret_t ftrace_graph_return;
 822 extern trace_func_graph_ent_t ftrace_graph_entry;
 823
 824 extern void unregister_ftrace_graph(void);
 825
 826 extern void ftrace_graph_init_task(struct task_struct *t);
 827 extern void ftrace_graph_exit_task(struct task_struct *t);
 828 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
 829
 830 static inline int task_curr_ret_stack(struct task_struct *t)
 831 {
 832         return t->curr_ret_stack;
 833 }
 834
 835 static inline void pause_graph_tracing(void)
 836 {
 837         atomic_inc(&current->tracing_graph_pause);
 838 }
 839
 840 static inline void unpause_graph_tracing(void)
 841 {
 842         atomic_dec(&current->tracing_graph_pause);
 843 }
 844 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */
 845
 846 #define __notrace_funcgraph
 847 #define INIT_FTRACE_GRAPH
 848
 849 static inline void ftrace_graph_init_task(struct task_struct *t) { }
 850 static inline void ftrace_graph_exit_task(struct task_struct *t) { }
 851 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
 852
 853 static inline int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 854                           trace_func_graph_ent_t entryfunc)
 855 {
 856         return -1;
 857 }
 858 static inline void unregister_ftrace_graph(void) { }
 859
 860 static inline int task_curr_ret_stack(struct task_struct *tsk)
 861 {
 862         return -1;
 863 }
 864
 865 static inline unsigned long
 866 ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret,
 867                       unsigned long *retp)
 868 {
 869         return ret;
 870 }
 871
 872 static inline void pause_graph_tracing(void) { }
 873 static inline void unpause_graph_tracing(void) { }
 874 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 875
 876 #ifdef CONFIG_TRACING
 877
 878 /* flags for current->trace */
 879 enum {
 880         TSK_TRACE_FL_TRACE_BIT  = 0,
 881         TSK_TRACE_FL_GRAPH_BIT  = 1,
 882 };
 883 enum {
 884         TSK_TRACE_FL_TRACE      = 1 << TSK_TRACE_FL_TRACE_BIT,
 885         TSK_TRACE_FL_GRAPH      = 1 << TSK_TRACE_FL_GRAPH_BIT,
 886 };
 887
 888 static inline void set_tsk_trace_trace(struct task_struct *tsk)
 889 {
 890         set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 891 }
 892
 893 static inline void clear_tsk_trace_trace(struct task_struct *tsk)
 894 {
 895         clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 896 }
 897
 898 static inline int test_tsk_trace_trace(struct task_struct *tsk)
 899 {
 900         return tsk->trace & TSK_TRACE_FL_TRACE;
 901 }
 902
 903 static inline void set_tsk_trace_graph(struct task_struct *tsk)
 904 {
 905         set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 906 }
 907
 908 static inline void clear_tsk_trace_graph(struct task_struct *tsk)
 909 {
 910         clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 911 }
 912
 913 static inline int test_tsk_trace_graph(struct task_struct *tsk)
 914 {
 915         return tsk->trace & TSK_TRACE_FL_GRAPH;
 916 }
 917
 918 enum ftrace_dump_mode;
 919
 920 extern enum ftrace_dump_mode ftrace_dump_on_oops;
 921 extern int tracepoint_printk;
 922
 923 extern void disable_trace_on_warning(void);
 924 extern int __disable_trace_on_warning;
 925
 926 #ifdef CONFIG_PREEMPT
 927 #define INIT_TRACE_RECURSION            .trace_recursion = 0,
 928 #endif
 929
 930 int tracepoint_printk_sysctl(struct ctl_table *table, int write,
 931                              void __user *buffer, size_t *lenp,
 932                              loff_t *ppos);
 933
 934 #else /* CONFIG_TRACING */
 935 static inline void  disable_trace_on_warning(void) { }
 936 #endif /* CONFIG_TRACING */
 937
 938 #ifndef INIT_TRACE_RECURSION
 939 #define INIT_TRACE_RECURSION
 940 #endif
 941
 942 #ifdef CONFIG_FTRACE_SYSCALLS
 943
 944 unsigned long arch_syscall_addr(int nr);
 945
 946 #endif /* CONFIG_FTRACE_SYSCALLS */
 947
 948 #endif /* _LINUX_FTRACE_H */