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.rst
   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
 227 extern void ftrace_stub(unsigned long a0, unsigned long a1,
 228                         struct ftrace_ops *op, struct pt_regs *regs);
 229
 230 #else /* !CONFIG_FUNCTION_TRACER */
 231 /*
 232  * (un)register_ftrace_function must be a macro since the ops parameter
 233  * must not be evaluated.
 234  */
 235 #define register_ftrace_function(ops) ({ 0; })
 236 #define unregister_ftrace_function(ops) ({ 0; })
 237 static inline void ftrace_kill(void) { }
 238 static inline void ftrace_free_init_mem(void) { }
 239 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }
 240 #endif /* CONFIG_FUNCTION_TRACER */
 241
 242 #ifdef CONFIG_STACK_TRACER
 243
 244 #define STACK_TRACE_ENTRIES 500
 245
 246 struct stack_trace;
 247
 248 extern unsigned stack_trace_index[];
 249 extern struct stack_trace stack_trace_max;
 250 extern unsigned long stack_trace_max_size;
 251 extern arch_spinlock_t stack_trace_max_lock;
 252
 253 extern int stack_tracer_enabled;
 254 void stack_trace_print(void);
 255 int
 256 stack_trace_sysctl(struct ctl_table *table, int write,
 257                    void __user *buffer, size_t *lenp,
 258                    loff_t *ppos);
 259
 260 /* DO NOT MODIFY THIS VARIABLE DIRECTLY! */
 261 DECLARE_PER_CPU(int, disable_stack_tracer);
 262
 263 /**
 264  * stack_tracer_disable - temporarily disable the stack tracer
 265  *
 266  * There's a few locations (namely in RCU) where stack tracing
 267  * cannot be executed. This function is used to disable stack
 268  * tracing during those critical sections.
 269  *
 270  * This function must be called with preemption or interrupts
 271  * disabled and stack_tracer_enable() must be called shortly after
 272  * while preemption or interrupts are still disabled.
 273  */
 274 static inline void stack_tracer_disable(void)
 275 {
 276         /* Preemption or interupts must be disabled */
 277         if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
 278                 WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
 279         this_cpu_inc(disable_stack_tracer);
 280 }
 281
 282 /**
 283  * stack_tracer_enable - re-enable the stack tracer
 284  *
 285  * After stack_tracer_disable() is called, stack_tracer_enable()
 286  * must be called shortly afterward.
 287  */
 288 static inline void stack_tracer_enable(void)
 289 {
 290         if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
 291                 WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
 292         this_cpu_dec(disable_stack_tracer);
 293 }
 294 #else
 295 static inline void stack_tracer_disable(void) { }
 296 static inline void stack_tracer_enable(void) { }
 297 #endif
 298
 299 #ifdef CONFIG_DYNAMIC_FTRACE
 300
 301 int ftrace_arch_code_modify_prepare(void);
 302 int ftrace_arch_code_modify_post_process(void);
 303
 304 struct dyn_ftrace;
 305
 306 enum ftrace_bug_type {
 307         FTRACE_BUG_UNKNOWN,
 308         FTRACE_BUG_INIT,
 309         FTRACE_BUG_NOP,
 310         FTRACE_BUG_CALL,
 311         FTRACE_BUG_UPDATE,
 312 };
 313 extern enum ftrace_bug_type ftrace_bug_type;
 314
 315 /*
 316  * Archs can set this to point to a variable that holds the value that was
 317  * expected at the call site before calling ftrace_bug().
 318  */
 319 extern const void *ftrace_expected;
 320
 321 void ftrace_bug(int err, struct dyn_ftrace *rec);
 322
 323 struct seq_file;
 324
 325 extern int ftrace_text_reserved(const void *start, const void *end);
 326
 327 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr);
 328
 329 bool is_ftrace_trampoline(unsigned long addr);
 330
 331 /*
 332  * The dyn_ftrace record's flags field is split into two parts.
 333  * the first part which is '0-FTRACE_REF_MAX' is a counter of
 334  * the number of callbacks that have registered the function that
 335  * the dyn_ftrace descriptor represents.
 336  *
 337  * The second part is a mask:
 338  *  ENABLED - the function is being traced
 339  *  REGS    - the record wants the function to save regs
 340  *  REGS_EN - the function is set up to save regs.
 341  *  IPMODIFY - the record allows for the IP address to be changed.
 342  *  DISABLED - the record is not ready to be touched yet
 343  *
 344  * When a new ftrace_ops is registered and wants a function to save
 345  * pt_regs, the rec->flag REGS is set. When the function has been
 346  * set up to save regs, the REG_EN flag is set. Once a function
 347  * starts saving regs it will do so until all ftrace_ops are removed
 348  * from tracing that function.
 349  */
 350 enum {
 351         FTRACE_FL_ENABLED       = (1UL << 31),
 352         FTRACE_FL_REGS          = (1UL << 30),
 353         FTRACE_FL_REGS_EN       = (1UL << 29),
 354         FTRACE_FL_TRAMP         = (1UL << 28),
 355         FTRACE_FL_TRAMP_EN      = (1UL << 27),
 356         FTRACE_FL_IPMODIFY      = (1UL << 26),
 357         FTRACE_FL_DISABLED      = (1UL << 25),
 358 };
 359
 360 #define FTRACE_REF_MAX_SHIFT    25
 361 #define FTRACE_FL_BITS          7
 362 #define FTRACE_FL_MASKED_BITS   ((1UL << FTRACE_FL_BITS) - 1)
 363 #define FTRACE_FL_MASK          (FTRACE_FL_MASKED_BITS << FTRACE_REF_MAX_SHIFT)
 364 #define FTRACE_REF_MAX          ((1UL << FTRACE_REF_MAX_SHIFT) - 1)
 365
 366 #define ftrace_rec_count(rec)   ((rec)->flags & ~FTRACE_FL_MASK)
 367
 368 struct dyn_ftrace {
 369         unsigned long           ip; /* address of mcount call-site */
 370         unsigned long           flags;
 371         struct dyn_arch_ftrace  arch;
 372 };
 373
 374 int ftrace_force_update(void);
 375 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
 376                          int remove, int reset);
 377 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
 378                        int len, int reset);
 379 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
 380                         int len, int reset);
 381 void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
 382 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
 383 void ftrace_free_filter(struct ftrace_ops *ops);
 384 void ftrace_ops_set_global_filter(struct ftrace_ops *ops);
 385
 386 enum {
 387         FTRACE_UPDATE_CALLS             = (1 << 0),
 388         FTRACE_DISABLE_CALLS            = (1 << 1),
 389         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
 390         FTRACE_START_FUNC_RET           = (1 << 3),
 391         FTRACE_STOP_FUNC_RET            = (1 << 4),
 392 };
 393
 394 /*
 395  * The FTRACE_UPDATE_* enum is used to pass information back
 396  * from the ftrace_update_record() and ftrace_test_record()
 397  * functions. These are called by the code update routines
 398  * to find out what is to be done for a given function.
 399  *
 400  *  IGNORE           - The function is already what we want it to be
 401  *  MAKE_CALL        - Start tracing the function
 402  *  MODIFY_CALL      - Stop saving regs for the function
 403  *  MAKE_NOP         - Stop tracing the function
 404  */
 405 enum {
 406         FTRACE_UPDATE_IGNORE,
 407         FTRACE_UPDATE_MAKE_CALL,
 408         FTRACE_UPDATE_MODIFY_CALL,
 409         FTRACE_UPDATE_MAKE_NOP,
 410 };
 411
 412 enum {
 413         FTRACE_ITER_FILTER      = (1 << 0),
 414         FTRACE_ITER_NOTRACE     = (1 << 1),
 415         FTRACE_ITER_PRINTALL    = (1 << 2),
 416         FTRACE_ITER_DO_PROBES   = (1 << 3),
 417         FTRACE_ITER_PROBE       = (1 << 4),
 418         FTRACE_ITER_MOD         = (1 << 5),
 419         FTRACE_ITER_ENABLED     = (1 << 6),
 420 };
 421
 422 void arch_ftrace_update_code(int command);
 423
 424 struct ftrace_rec_iter;
 425
 426 struct ftrace_rec_iter *ftrace_rec_iter_start(void);
 427 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
 428 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);
 429
 430 #define for_ftrace_rec_iter(iter)               \
 431         for (iter = ftrace_rec_iter_start();    \
 432              iter;                              \
 433              iter = ftrace_rec_iter_next(iter))
 434
 435
 436 int ftrace_update_record(struct dyn_ftrace *rec, int enable);
 437 int ftrace_test_record(struct dyn_ftrace *rec, int enable);
 438 void ftrace_run_stop_machine(int command);
 439 unsigned long ftrace_location(unsigned long ip);
 440 unsigned long ftrace_location_range(unsigned long start, unsigned long end);
 441 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec);
 442 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec);
 443
 444 extern ftrace_func_t ftrace_trace_function;
 445
 446 int ftrace_regex_open(struct ftrace_ops *ops, int flag,
 447                   struct inode *inode, struct file *file);
 448 ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 449                             size_t cnt, loff_t *ppos);
 450 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 451                              size_t cnt, loff_t *ppos);
 452 int ftrace_regex_release(struct inode *inode, struct file *file);
 453
 454 void __init
 455 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
 456
 457 /* defined in arch */
 458 extern int ftrace_ip_converted(unsigned long ip);
 459 extern int ftrace_dyn_arch_init(void);
 460 extern void ftrace_replace_code(int enable);
 461 extern int ftrace_update_ftrace_func(ftrace_func_t func);
 462 extern void ftrace_caller(void);
 463 extern void ftrace_regs_caller(void);
 464 extern void ftrace_call(void);
 465 extern void ftrace_regs_call(void);
 466 extern void mcount_call(void);
 467
 468 void ftrace_modify_all_code(int command);
 469
 470 #ifndef FTRACE_ADDR
 471 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
 472 #endif
 473
 474 #ifndef FTRACE_GRAPH_ADDR
 475 #define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller)
 476 #endif
 477
 478 #ifndef FTRACE_REGS_ADDR
 479 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 480 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller)
 481 #else
 482 # define FTRACE_REGS_ADDR FTRACE_ADDR
 483 #endif
 484 #endif
 485
 486 /*
 487  * If an arch would like functions that are only traced
 488  * by the function graph tracer to jump directly to its own
 489  * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR
 490  * to be that address to jump to.
 491  */
 492 #ifndef FTRACE_GRAPH_TRAMP_ADDR
 493 #define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0)
 494 #endif
 495
 496 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 497 extern void ftrace_graph_caller(void);
 498 extern int ftrace_enable_ftrace_graph_caller(void);
 499 extern int ftrace_disable_ftrace_graph_caller(void);
 500 #else
 501 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
 502 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
 503 #endif
 504
 505 /**
 506  * ftrace_make_nop - convert code into nop
 507  * @mod: module structure if called by module load initialization
 508  * @rec: the mcount call site record
 509  * @addr: the address that the call site should be calling
 510  *
 511  * This is a very sensitive operation and great care needs
 512  * to be taken by the arch.  The operation should carefully
 513  * read the location, check to see if what is read is indeed
 514  * what we expect it to be, and then on success of the compare,
 515  * it should write to the location.
 516  *
 517  * The code segment at @rec->ip should be a caller to @addr
 518  *
 519  * Return must be:
 520  *  0 on success
 521  *  -EFAULT on error reading the location
 522  *  -EINVAL on a failed compare of the contents
 523  *  -EPERM  on error writing to the location
 524  * Any other value will be considered a failure.
 525  */
 526 extern int ftrace_make_nop(struct module *mod,
 527                            struct dyn_ftrace *rec, unsigned long addr);
 528
 529 /**
 530  * ftrace_make_call - convert a nop call site into a call to addr
 531  * @rec: the mcount call site record
 532  * @addr: the address that the call site should call
 533  *
 534  * This is a very sensitive operation and great care needs
 535  * to be taken by the arch.  The operation should carefully
 536  * read the location, check to see if what is read is indeed
 537  * what we expect it to be, and then on success of the compare,
 538  * it should write to the location.
 539  *
 540  * The code segment at @rec->ip should be a nop
 541  *
 542  * Return must be:
 543  *  0 on success
 544  *  -EFAULT on error reading the location
 545  *  -EINVAL on a failed compare of the contents
 546  *  -EPERM  on error writing to the location
 547  * Any other value will be considered a failure.
 548  */
 549 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
 550
 551 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 552 /**
 553  * ftrace_modify_call - convert from one addr to another (no nop)
 554  * @rec: the mcount call site record
 555  * @old_addr: the address expected to be currently called to
 556  * @addr: the address to change to
 557  *
 558  * This is a very sensitive operation and great care needs
 559  * to be taken by the arch.  The operation should carefully
 560  * read the location, check to see if what is read is indeed
 561  * what we expect it to be, and then on success of the compare,
 562  * it should write to the location.
 563  *
 564  * The code segment at @rec->ip should be a caller to @old_addr
 565  *
 566  * Return must be:
 567  *  0 on success
 568  *  -EFAULT on error reading the location
 569  *  -EINVAL on a failed compare of the contents
 570  *  -EPERM  on error writing to the location
 571  * Any other value will be considered a failure.
 572  */
 573 extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 574                               unsigned long addr);
 575 #else
 576 /* Should never be called */
 577 static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 578                                      unsigned long addr)
 579 {
 580         return -EINVAL;
 581 }
 582 #endif
 583
 584 /* May be defined in arch */
 585 extern int ftrace_arch_read_dyn_info(char *buf, int size);
 586
 587 extern int skip_trace(unsigned long ip);
 588 extern void ftrace_module_init(struct module *mod);
 589 extern void ftrace_module_enable(struct module *mod);
 590 extern void ftrace_release_mod(struct module *mod);
 591
 592 extern void ftrace_disable_daemon(void);
 593 extern void ftrace_enable_daemon(void);
 594 #else /* CONFIG_DYNAMIC_FTRACE */
 595 static inline int skip_trace(unsigned long ip) { return 0; }
 596 static inline int ftrace_force_update(void) { return 0; }
 597 static inline void ftrace_disable_daemon(void) { }
 598 static inline void ftrace_enable_daemon(void) { }
 599 static inline void ftrace_module_init(struct module *mod) { }
 600 static inline void ftrace_module_enable(struct module *mod) { }
 601 static inline void ftrace_release_mod(struct module *mod) { }
 602 static inline int ftrace_text_reserved(const void *start, const void *end)
 603 {
 604         return 0;
 605 }
 606 static inline unsigned long ftrace_location(unsigned long ip)
 607 {
 608         return 0;
 609 }
 610
 611 /*
 612  * Again users of functions that have ftrace_ops may not
 613  * have them defined when ftrace is not enabled, but these
 614  * functions may still be called. Use a macro instead of inline.
 615  */
 616 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
 617 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
 618 #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; })
 619 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
 620 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
 621 #define ftrace_free_filter(ops) do { } while (0)
 622 #define ftrace_ops_set_global_filter(ops) do { } while (0)
 623
 624 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 625                             size_t cnt, loff_t *ppos) { return -ENODEV; }
 626 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 627                              size_t cnt, loff_t *ppos) { return -ENODEV; }
 628 static inline int
 629 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
 630
 631 static inline bool is_ftrace_trampoline(unsigned long addr)
 632 {
 633         return false;
 634 }
 635 #endif /* CONFIG_DYNAMIC_FTRACE */
 636
 637 /* totally disable ftrace - can not re-enable after this */
 638 void ftrace_kill(void);
 639
 640 static inline void tracer_disable(void)
 641 {
 642 #ifdef CONFIG_FUNCTION_TRACER
 643         ftrace_enabled = 0;
 644 #endif
 645 }
 646
 647 /*
 648  * Ftrace disable/restore without lock. Some synchronization mechanism
 649  * must be used to prevent ftrace_enabled to be changed between
 650  * disable/restore.
 651  */
 652 static inline int __ftrace_enabled_save(void)
 653 {
 654 #ifdef CONFIG_FUNCTION_TRACER
 655         int saved_ftrace_enabled = ftrace_enabled;
 656         ftrace_enabled = 0;
 657         return saved_ftrace_enabled;
 658 #else
 659         return 0;
 660 #endif
 661 }
 662
 663 static inline void __ftrace_enabled_restore(int enabled)
 664 {
 665 #ifdef CONFIG_FUNCTION_TRACER
 666         ftrace_enabled = enabled;
 667 #endif
 668 }
 669
 670 /* All archs should have this, but we define it for consistency */
 671 #ifndef ftrace_return_address0
 672 # define ftrace_return_address0 __builtin_return_address(0)
 673 #endif
 674
 675 /* Archs may use other ways for ADDR1 and beyond */
 676 #ifndef ftrace_return_address
 677 # ifdef CONFIG_FRAME_POINTER
 678 #  define ftrace_return_address(n) __builtin_return_address(n)
 679 # else
 680 #  define ftrace_return_address(n) 0UL
 681 # endif
 682 #endif
 683
 684 #define CALLER_ADDR0 ((unsigned long)ftrace_return_address0)
 685 #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1))
 686 #define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2))
 687 #define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3))
 688 #define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4))
 689 #define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5))
 690 #define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6))
 691
 692 static inline unsigned long get_lock_parent_ip(void)
 693 {
 694         unsigned long addr = CALLER_ADDR0;
 695
 696         if (!in_lock_functions(addr))
 697                 return addr;
 698         addr = CALLER_ADDR1;
 699         if (!in_lock_functions(addr))
 700                 return addr;
 701         return CALLER_ADDR2;
 702 }
 703
 704 #ifdef CONFIG_TRACE_PREEMPT_TOGGLE
 705   extern void trace_preempt_on(unsigned long a0, unsigned long a1);
 706   extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 707 #else
 708 /*
 709  * Use defines instead of static inlines because some arches will make code out
 710  * of the CALLER_ADDR, when we really want these to be a real nop.
 711  */
 712 # define trace_preempt_on(a0, a1) do { } while (0)
 713 # define trace_preempt_off(a0, a1) do { } while (0)
 714 #endif
 715
 716 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 717 extern void ftrace_init(void);
 718 #else
 719 static inline void ftrace_init(void) { }
 720 #endif
 721
 722 /*
 723  * Structure that defines an entry function trace.
 724  * It's already packed but the attribute "packed" is needed
 725  * to remove extra padding at the end.
 726  */
 727 struct ftrace_graph_ent {
 728         unsigned long func; /* Current function */
 729         int depth;
 730 } __packed;
 731
 732 /*
 733  * Structure that defines a return function trace.
 734  * It's already packed but the attribute "packed" is needed
 735  * to remove extra padding at the end.
 736  */
 737 struct ftrace_graph_ret {
 738         unsigned long func; /* Current function */
 739         /* Number of functions that overran the depth limit for current task */
 740         unsigned long overrun;
 741         unsigned long long calltime;
 742         unsigned long long rettime;
 743         int depth;
 744 } __packed;
 745
 746 /* Type of the callback handlers for tracing function graph*/
 747 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
 748 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
 749
 750 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 751
 752 /*
 753  * Stack of return addresses for functions
 754  * of a thread.
 755  * Used in struct thread_info
 756  */
 757 struct ftrace_ret_stack {
 758         unsigned long ret;
 759         unsigned long func;
 760         unsigned long long calltime;
 761 #ifdef CONFIG_FUNCTION_PROFILER
 762         unsigned long long subtime;
 763 #endif
 764 #ifdef HAVE_FUNCTION_GRAPH_FP_TEST
 765         unsigned long fp;
 766 #endif
 767 #ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
 768         unsigned long *retp;
 769 #endif
 770 };
 771
 772 /*
 773  * Primary handler of a function return.
 774  * It relays on ftrace_return_to_handler.
 775  * Defined in entry_32/64.S
 776  */
 777 extern void return_to_handler(void);
 778
 779 extern int
 780 function_graph_enter(unsigned long ret, unsigned long func,
 781                      unsigned long frame_pointer, unsigned long *retp);
 782
 783 unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
 784                                     unsigned long ret, unsigned long *retp);
 785
 786 /*
 787  * Sometimes we don't want to trace a function with the function
 788  * graph tracer but we want them to keep traced by the usual function
 789  * tracer if the function graph tracer is not configured.
 790  */
 791 #define __notrace_funcgraph             notrace
 792
 793 #define FTRACE_NOTRACE_DEPTH 65536
 794 #define FTRACE_RETFUNC_DEPTH 50
 795 #define FTRACE_RETSTACK_ALLOC_SIZE 32
 796 extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 797                                 trace_func_graph_ent_t entryfunc);
 798
 799 extern bool ftrace_graph_is_dead(void);
 800 extern void ftrace_graph_stop(void);
 801
 802 /* The current handlers in use */
 803 extern trace_func_graph_ret_t ftrace_graph_return;
 804 extern trace_func_graph_ent_t ftrace_graph_entry;
 805
 806 extern void unregister_ftrace_graph(void);
 807
 808 extern void ftrace_graph_init_task(struct task_struct *t);
 809 extern void ftrace_graph_exit_task(struct task_struct *t);
 810 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
 811
 812 static inline int task_curr_ret_stack(struct task_struct *t)
 813 {
 814         return t->curr_ret_stack;
 815 }
 816
 817 static inline void pause_graph_tracing(void)
 818 {
 819         atomic_inc(&current->tracing_graph_pause);
 820 }
 821
 822 static inline void unpause_graph_tracing(void)
 823 {
 824         atomic_dec(&current->tracing_graph_pause);
 825 }
 826 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */
 827
 828 #define __notrace_funcgraph
 829
 830 static inline void ftrace_graph_init_task(struct task_struct *t) { }
 831 static inline void ftrace_graph_exit_task(struct task_struct *t) { }
 832 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
 833
 834 static inline int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 835                           trace_func_graph_ent_t entryfunc)
 836 {
 837         return -1;
 838 }
 839 static inline void unregister_ftrace_graph(void) { }
 840
 841 static inline int task_curr_ret_stack(struct task_struct *tsk)
 842 {
 843         return -1;
 844 }
 845
 846 static inline unsigned long
 847 ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret,
 848                       unsigned long *retp)
 849 {
 850         return ret;
 851 }
 852
 853 static inline void pause_graph_tracing(void) { }
 854 static inline void unpause_graph_tracing(void) { }
 855 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 856
 857 #ifdef CONFIG_TRACING
 858
 859 /* flags for current->trace */
 860 enum {
 861         TSK_TRACE_FL_TRACE_BIT  = 0,
 862         TSK_TRACE_FL_GRAPH_BIT  = 1,
 863 };
 864 enum {
 865         TSK_TRACE_FL_TRACE      = 1 << TSK_TRACE_FL_TRACE_BIT,
 866         TSK_TRACE_FL_GRAPH      = 1 << TSK_TRACE_FL_GRAPH_BIT,
 867 };
 868
 869 static inline void set_tsk_trace_trace(struct task_struct *tsk)
 870 {
 871         set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 872 }
 873
 874 static inline void clear_tsk_trace_trace(struct task_struct *tsk)
 875 {
 876         clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 877 }
 878
 879 static inline int test_tsk_trace_trace(struct task_struct *tsk)
 880 {
 881         return tsk->trace & TSK_TRACE_FL_TRACE;
 882 }
 883
 884 static inline void set_tsk_trace_graph(struct task_struct *tsk)
 885 {
 886         set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 887 }
 888
 889 static inline void clear_tsk_trace_graph(struct task_struct *tsk)
 890 {
 891         clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 892 }
 893
 894 static inline int test_tsk_trace_graph(struct task_struct *tsk)
 895 {
 896         return tsk->trace & TSK_TRACE_FL_GRAPH;
 897 }
 898
 899 enum ftrace_dump_mode;
 900
 901 extern enum ftrace_dump_mode ftrace_dump_on_oops;
 902 extern int tracepoint_printk;
 903
 904 extern void disable_trace_on_warning(void);
 905 extern int __disable_trace_on_warning;
 906
 907 int tracepoint_printk_sysctl(struct ctl_table *table, int write,
 908                              void __user *buffer, size_t *lenp,
 909                              loff_t *ppos);
 910
 911 #else /* CONFIG_TRACING */
 912 static inline void  disable_trace_on_warning(void) { }
 913 #endif /* CONFIG_TRACING */
 914
 915 #ifdef CONFIG_FTRACE_SYSCALLS
 916
 917 unsigned long arch_syscall_addr(int nr);
 918
 919 #endif /* CONFIG_FTRACE_SYSCALLS */
 920
 921 #endif /* _LINUX_FTRACE_H */