include/linux/ftrace.h

   1 /*
   2  * Ftrace header.  For implementation details beyond the random comments
   3  * scattered below, see: Documentation/trace/ftrace-design.txt
   4  */
   5
   6 #ifndef _LINUX_FTRACE_H
   7 #define _LINUX_FTRACE_H
   8
   9 #include <linux/trace_clock.h>
  10 #include <linux/kallsyms.h>
  11 #include <linux/linkage.h>
  12 #include <linux/bitops.h>
  13 #include <linux/ptrace.h>
  14 #include <linux/ktime.h>
  15 #include <linux/sched.h>
  16 #include <linux/types.h>
  17 #include <linux/init.h>
  18 #include <linux/fs.h>
  19
  20 #include <asm/ftrace.h>
  21
  22 /*
  23  * If the arch supports passing the variable contents of
  24  * function_trace_op as the third parameter back from the
  25  * mcount call, then the arch should define this as 1.
  26  */
  27 #ifndef ARCH_SUPPORTS_FTRACE_OPS
  28 #define ARCH_SUPPORTS_FTRACE_OPS 0
  29 #endif
  30
  31 /*
  32  * If the arch's mcount caller does not support all of ftrace's
  33  * features, then it must call an indirect function that
  34  * does. Or at least does enough to prevent any unwelcomed side effects.
  35  */
  36 #if !ARCH_SUPPORTS_FTRACE_OPS
  37 # define FTRACE_FORCE_LIST_FUNC 1
  38 #else
  39 # define FTRACE_FORCE_LIST_FUNC 0
  40 #endif
  41
  42 /* Main tracing buffer and events set up */
  43 #ifdef CONFIG_TRACING
  44 void trace_init(void);
  45 void early_trace_init(void);
  46 #else
  47 static inline void trace_init(void) { }
  48 static inline void early_trace_init(void) { }
  49 #endif
  50
  51 struct module;
  52 struct ftrace_hash;
  53
  54 #ifdef CONFIG_FUNCTION_TRACER
  55
  56 extern int ftrace_enabled;
  57 extern int
  58 ftrace_enable_sysctl(struct ctl_table *table, int write,
  59                      void __user *buffer, size_t *lenp,
  60                      loff_t *ppos);
  61
  62 struct ftrace_ops;
  63
  64 typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
  65                               struct ftrace_ops *op, struct pt_regs *regs);
  66
  67 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops);
  68
  69 /*
  70  * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are
  71  * set in the flags member.
  72  * CONTROL, SAVE_REGS, SAVE_REGS_IF_SUPPORTED, RECURSION_SAFE, STUB and
  73  * IPMODIFY are a kind of attribute flags which can be set only before
  74  * registering the ftrace_ops, and can not be modified while registered.
  75  * Changing those attribute flags after registering ftrace_ops will
  76  * cause unexpected results.
  77  *
  78  * ENABLED - set/unset when ftrace_ops is registered/unregistered
  79  * DYNAMIC - set when ftrace_ops is registered to denote dynamically
  80  *           allocated ftrace_ops which need special care
  81  * PER_CPU - set manualy by ftrace_ops user to denote the ftrace_ops
  82  *           could be controlled by following calls:
  83  *             ftrace_function_local_enable
  84  *             ftrace_function_local_disable
  85  * SAVE_REGS - The ftrace_ops wants regs saved at each function called
  86  *            and passed to the callback. If this flag is set, but the
  87  *            architecture does not support passing regs
  88  *            (CONFIG_DYNAMIC_FTRACE_WITH_REGS is not defined), then the
  89  *            ftrace_ops will fail to register, unless the next flag
  90  *            is set.
  91  * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the
  92  *            handler can handle an arch that does not save regs
  93  *            (the handler tests if regs == NULL), then it can set
  94  *            this flag instead. It will not fail registering the ftrace_ops
  95  *            but, the regs field will be NULL if the arch does not support
  96  *            passing regs to the handler.
  97  *            Note, if this flag is set, the SAVE_REGS flag will automatically
  98  *            get set upon registering the ftrace_ops, if the arch supports it.
  99  * RECURSION_SAFE - The ftrace_ops can set this to tell the ftrace infrastructure
 100  *            that the call back has its own recursion protection. If it does
 101  *            not set this, then the ftrace infrastructure will add recursion
 102  *            protection for the caller.
 103  * STUB   - The ftrace_ops is just a place holder.
 104  * INITIALIZED - The ftrace_ops has already been initialized (first use time
 105  *            register_ftrace_function() is called, it will initialized the ops)
 106  * DELETED - The ops are being deleted, do not let them be registered again.
 107  * ADDING  - The ops is in the process of being added.
 108  * REMOVING - The ops is in the process of being removed.
 109  * MODIFYING - The ops is in the process of changing its filter functions.
 110  * ALLOC_TRAMP - A dynamic trampoline was allocated by the core code.
 111  *            The arch specific code sets this flag when it allocated a
 112  *            trampoline. This lets the arch know that it can update the
 113  *            trampoline in case the callback function changes.
 114  *            The ftrace_ops trampoline can be set by the ftrace users, and
 115  *            in such cases the arch must not modify it. Only the arch ftrace
 116  *            core code should set this flag.
 117  * IPMODIFY - The ops can modify the IP register. This can only be set with
 118  *            SAVE_REGS. If another ops with this flag set is already registered
 119  *            for any of the functions that this ops will be registered for, then
 120  *            this ops will fail to register or set_filter_ip.
 121  * PID     - Is affected by set_ftrace_pid (allows filtering on those pids)
 122  * RCU     - Set when the ops can only be called when RCU is watching.
 123  * TRACE_ARRAY - The ops->private points to a trace_array descriptor.
 124  */
 125 enum {
 126         FTRACE_OPS_FL_ENABLED                   = 1 << 0,
 127         FTRACE_OPS_FL_DYNAMIC                   = 1 << 1,
 128         FTRACE_OPS_FL_PER_CPU                   = 1 << 2,
 129         FTRACE_OPS_FL_SAVE_REGS                 = 1 << 3,
 130         FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED    = 1 << 4,
 131         FTRACE_OPS_FL_RECURSION_SAFE            = 1 << 5,
 132         FTRACE_OPS_FL_STUB                      = 1 << 6,
 133         FTRACE_OPS_FL_INITIALIZED               = 1 << 7,
 134         FTRACE_OPS_FL_DELETED                   = 1 << 8,
 135         FTRACE_OPS_FL_ADDING                    = 1 << 9,
 136         FTRACE_OPS_FL_REMOVING                  = 1 << 10,
 137         FTRACE_OPS_FL_MODIFYING                 = 1 << 11,
 138         FTRACE_OPS_FL_ALLOC_TRAMP               = 1 << 12,
 139         FTRACE_OPS_FL_IPMODIFY                  = 1 << 13,
 140         FTRACE_OPS_FL_PID                       = 1 << 14,
 141         FTRACE_OPS_FL_RCU                       = 1 << 15,
 142         FTRACE_OPS_FL_TRACE_ARRAY               = 1 << 16,
 143 };
 144
 145 #ifdef CONFIG_DYNAMIC_FTRACE
 146 /* The hash used to know what functions callbacks trace */
 147 struct ftrace_ops_hash {
 148         struct ftrace_hash              *notrace_hash;
 149         struct ftrace_hash              *filter_hash;
 150         struct mutex                    regex_lock;
 151 };
 152
 153 void ftrace_free_init_mem(void);
 154 #else
 155 static inline void ftrace_free_init_mem(void) { }
 156 #endif
 157
 158 /*
 159  * Note, ftrace_ops can be referenced outside of RCU protection, unless
 160  * the RCU flag is set. If ftrace_ops is allocated and not part of kernel
 161  * core data, the unregistering of it will perform a scheduling on all CPUs
 162  * to make sure that there are no more users. Depending on the load of the
 163  * system that may take a bit of time.
 164  *
 165  * Any private data added must also take care not to be freed and if private
 166  * data is added to a ftrace_ops that is in core code, the user of the
 167  * ftrace_ops must perform a schedule_on_each_cpu() before freeing it.
 168  */
 169 struct ftrace_ops {
 170         ftrace_func_t                   func;
 171         struct ftrace_ops               *next;
 172         unsigned long                   flags;
 173         void                            *private;
 174         ftrace_func_t                   saved_func;
 175         int __percpu                    *disabled;
 176 #ifdef CONFIG_DYNAMIC_FTRACE
 177         struct ftrace_ops_hash          local_hash;
 178         struct ftrace_ops_hash          *func_hash;
 179         struct ftrace_ops_hash          old_hash;
 180         unsigned long                   trampoline;
 181         unsigned long                   trampoline_size;
 182 #endif
 183 };
 184
 185 /*
 186  * Type of the current tracing.
 187  */
 188 enum ftrace_tracing_type_t {
 189         FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
 190         FTRACE_TYPE_RETURN,     /* Hook the return of the function */
 191 };
 192
 193 /* Current tracing type, default is FTRACE_TYPE_ENTER */
 194 extern enum ftrace_tracing_type_t ftrace_tracing_type;
 195
 196 /*
 197  * The ftrace_ops must be a static and should also
 198  * be read_mostly.  These functions do modify read_mostly variables
 199  * so use them sparely. Never free an ftrace_op or modify the
 200  * next pointer after it has been registered. Even after unregistering
 201  * it, the next pointer may still be used internally.
 202  */
 203 int register_ftrace_function(struct ftrace_ops *ops);
 204 int unregister_ftrace_function(struct ftrace_ops *ops);
 205 void clear_ftrace_function(void);
 206
 207 /**
 208  * ftrace_function_local_enable - enable ftrace_ops on current cpu
 209  *
 210  * This function enables tracing on current cpu by decreasing
 211  * the per cpu control variable.
 212  * It must be called with preemption disabled and only on ftrace_ops
 213  * registered with FTRACE_OPS_FL_PER_CPU. If called without preemption
 214  * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
 215  */
 216 static inline void ftrace_function_local_enable(struct ftrace_ops *ops)
 217 {
 218         if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU)))
 219                 return;
 220
 221         (*this_cpu_ptr(ops->disabled))--;
 222 }
 223
 224 /**
 225  * ftrace_function_local_disable - disable ftrace_ops on current cpu
 226  *
 227  * This function disables tracing on current cpu by increasing
 228  * the per cpu control variable.
 229  * It must be called with preemption disabled and only on ftrace_ops
 230  * registered with FTRACE_OPS_FL_PER_CPU. If called without preemption
 231  * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
 232  */
 233 static inline void ftrace_function_local_disable(struct ftrace_ops *ops)
 234 {
 235         if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU)))
 236                 return;
 237
 238         (*this_cpu_ptr(ops->disabled))++;
 239 }
 240
 241 /**
 242  * ftrace_function_local_disabled - returns ftrace_ops disabled value
 243  *                                  on current cpu
 244  *
 245  * This function returns value of ftrace_ops::disabled on current cpu.
 246  * It must be called with preemption disabled and only on ftrace_ops
 247  * registered with FTRACE_OPS_FL_PER_CPU. If called without preemption
 248  * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
 249  */
 250 static inline int ftrace_function_local_disabled(struct ftrace_ops *ops)
 251 {
 252         WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU));
 253         return *this_cpu_ptr(ops->disabled);
 254 }
 255
 256 extern void ftrace_stub(unsigned long a0, unsigned long a1,
 257                         struct ftrace_ops *op, struct pt_regs *regs);
 258
 259 #else /* !CONFIG_FUNCTION_TRACER */
 260 /*
 261  * (un)register_ftrace_function must be a macro since the ops parameter
 262  * must not be evaluated.
 263  */
 264 #define register_ftrace_function(ops) ({ 0; })
 265 #define unregister_ftrace_function(ops) ({ 0; })
 266 static inline int ftrace_nr_registered_ops(void)
 267 {
 268         return 0;
 269 }
 270 static inline void clear_ftrace_function(void) { }
 271 static inline void ftrace_kill(void) { }
 272 static inline void ftrace_free_init_mem(void) { }
 273 #endif /* CONFIG_FUNCTION_TRACER */
 274
 275 #ifdef CONFIG_STACK_TRACER
 276
 277 #define STACK_TRACE_ENTRIES 500
 278
 279 struct stack_trace;
 280
 281 extern unsigned stack_trace_index[];
 282 extern struct stack_trace stack_trace_max;
 283 extern unsigned long stack_trace_max_size;
 284 extern arch_spinlock_t stack_trace_max_lock;
 285
 286 extern int stack_tracer_enabled;
 287 void stack_trace_print(void);
 288 int
 289 stack_trace_sysctl(struct ctl_table *table, int write,
 290                    void __user *buffer, size_t *lenp,
 291                    loff_t *ppos);
 292
 293 /* DO NOT MODIFY THIS VARIABLE DIRECTLY! */
 294 DECLARE_PER_CPU(int, disable_stack_tracer);
 295
 296 /**
 297  * stack_tracer_disable - temporarily disable the stack tracer
 298  *
 299  * There's a few locations (namely in RCU) where stack tracing
 300  * cannot be executed. This function is used to disable stack
 301  * tracing during those critical sections.
 302  *
 303  * This function must be called with preemption or interrupts
 304  * disabled and stack_tracer_enable() must be called shortly after
 305  * while preemption or interrupts are still disabled.
 306  */
 307 static inline void stack_tracer_disable(void)
 308 {
 309         /* Preemption or interupts must be disabled */
 310         if (IS_ENABLED(CONFIG_PREEMPT_DEBUG))
 311                 WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
 312         this_cpu_inc(disable_stack_tracer);
 313 }
 314
 315 /**
 316  * stack_tracer_enable - re-enable the stack tracer
 317  *
 318  * After stack_tracer_disable() is called, stack_tracer_enable()
 319  * must be called shortly afterward.
 320  */
 321 static inline void stack_tracer_enable(void)
 322 {
 323         if (IS_ENABLED(CONFIG_PREEMPT_DEBUG))
 324                 WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
 325         this_cpu_dec(disable_stack_tracer);
 326 }
 327 #else
 328 static inline void stack_tracer_disable(void) { }
 329 static inline void stack_tracer_enable(void) { }
 330 #endif
 331
 332 #ifdef CONFIG_DYNAMIC_FTRACE
 333
 334 int ftrace_arch_code_modify_prepare(void);
 335 int ftrace_arch_code_modify_post_process(void);
 336
 337 struct dyn_ftrace;
 338
 339 enum ftrace_bug_type {
 340         FTRACE_BUG_UNKNOWN,
 341         FTRACE_BUG_INIT,
 342         FTRACE_BUG_NOP,
 343         FTRACE_BUG_CALL,
 344         FTRACE_BUG_UPDATE,
 345 };
 346 extern enum ftrace_bug_type ftrace_bug_type;
 347
 348 /*
 349  * Archs can set this to point to a variable that holds the value that was
 350  * expected at the call site before calling ftrace_bug().
 351  */
 352 extern const void *ftrace_expected;
 353
 354 void ftrace_bug(int err, struct dyn_ftrace *rec);
 355
 356 struct seq_file;
 357
 358 extern int ftrace_text_reserved(const void *start, const void *end);
 359
 360 extern int ftrace_nr_registered_ops(void);
 361
 362 bool is_ftrace_trampoline(unsigned long addr);
 363
 364 /*
 365  * The dyn_ftrace record's flags field is split into two parts.
 366  * the first part which is '0-FTRACE_REF_MAX' is a counter of
 367  * the number of callbacks that have registered the function that
 368  * the dyn_ftrace descriptor represents.
 369  *
 370  * The second part is a mask:
 371  *  ENABLED - the function is being traced
 372  *  REGS    - the record wants the function to save regs
 373  *  REGS_EN - the function is set up to save regs.
 374  *  IPMODIFY - the record allows for the IP address to be changed.
 375  *  DISABLED - the record is not ready to be touched yet
 376  *
 377  * When a new ftrace_ops is registered and wants a function to save
 378  * pt_regs, the rec->flag REGS is set. When the function has been
 379  * set up to save regs, the REG_EN flag is set. Once a function
 380  * starts saving regs it will do so until all ftrace_ops are removed
 381  * from tracing that function.
 382  */
 383 enum {
 384         FTRACE_FL_ENABLED       = (1UL << 31),
 385         FTRACE_FL_REGS          = (1UL << 30),
 386         FTRACE_FL_REGS_EN       = (1UL << 29),
 387         FTRACE_FL_TRAMP         = (1UL << 28),
 388         FTRACE_FL_TRAMP_EN      = (1UL << 27),
 389         FTRACE_FL_IPMODIFY      = (1UL << 26),
 390         FTRACE_FL_DISABLED      = (1UL << 25),
 391 };
 392
 393 #define FTRACE_REF_MAX_SHIFT    25
 394 #define FTRACE_FL_BITS          7
 395 #define FTRACE_FL_MASKED_BITS   ((1UL << FTRACE_FL_BITS) - 1)
 396 #define FTRACE_FL_MASK          (FTRACE_FL_MASKED_BITS << FTRACE_REF_MAX_SHIFT)
 397 #define FTRACE_REF_MAX          ((1UL << FTRACE_REF_MAX_SHIFT) - 1)
 398
 399 #define ftrace_rec_count(rec)   ((rec)->flags & ~FTRACE_FL_MASK)
 400
 401 struct dyn_ftrace {
 402         unsigned long           ip; /* address of mcount call-site */
 403         unsigned long           flags;
 404         struct dyn_arch_ftrace  arch;
 405 };
 406
 407 int ftrace_force_update(void);
 408 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
 409                          int remove, int reset);
 410 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
 411                        int len, int reset);
 412 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
 413                         int len, int reset);
 414 void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
 415 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
 416 void ftrace_free_filter(struct ftrace_ops *ops);
 417 void ftrace_ops_set_global_filter(struct ftrace_ops *ops);
 418
 419 enum {
 420         FTRACE_UPDATE_CALLS             = (1 << 0),
 421         FTRACE_DISABLE_CALLS            = (1 << 1),
 422         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
 423         FTRACE_START_FUNC_RET           = (1 << 3),
 424         FTRACE_STOP_FUNC_RET            = (1 << 4),
 425 };
 426
 427 /*
 428  * The FTRACE_UPDATE_* enum is used to pass information back
 429  * from the ftrace_update_record() and ftrace_test_record()
 430  * functions. These are called by the code update routines
 431  * to find out what is to be done for a given function.
 432  *
 433  *  IGNORE           - The function is already what we want it to be
 434  *  MAKE_CALL        - Start tracing the function
 435  *  MODIFY_CALL      - Stop saving regs for the function
 436  *  MAKE_NOP         - Stop tracing the function
 437  */
 438 enum {
 439         FTRACE_UPDATE_IGNORE,
 440         FTRACE_UPDATE_MAKE_CALL,
 441         FTRACE_UPDATE_MODIFY_CALL,
 442         FTRACE_UPDATE_MAKE_NOP,
 443 };
 444
 445 enum {
 446         FTRACE_ITER_FILTER      = (1 << 0),
 447         FTRACE_ITER_NOTRACE     = (1 << 1),
 448         FTRACE_ITER_PRINTALL    = (1 << 2),
 449         FTRACE_ITER_DO_PROBES   = (1 << 3),
 450         FTRACE_ITER_PROBE       = (1 << 4),
 451         FTRACE_ITER_MOD         = (1 << 5),
 452         FTRACE_ITER_ENABLED     = (1 << 6),
 453 };
 454
 455 void arch_ftrace_update_code(int command);
 456
 457 struct ftrace_rec_iter;
 458
 459 struct ftrace_rec_iter *ftrace_rec_iter_start(void);
 460 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
 461 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);
 462
 463 #define for_ftrace_rec_iter(iter)               \
 464         for (iter = ftrace_rec_iter_start();    \
 465              iter;                              \
 466              iter = ftrace_rec_iter_next(iter))
 467
 468
 469 int ftrace_update_record(struct dyn_ftrace *rec, int enable);
 470 int ftrace_test_record(struct dyn_ftrace *rec, int enable);
 471 void ftrace_run_stop_machine(int command);
 472 unsigned long ftrace_location(unsigned long ip);
 473 unsigned long ftrace_location_range(unsigned long start, unsigned long end);
 474 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec);
 475 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec);
 476
 477 extern ftrace_func_t ftrace_trace_function;
 478
 479 int ftrace_regex_open(struct ftrace_ops *ops, int flag,
 480                   struct inode *inode, struct file *file);
 481 ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 482                             size_t cnt, loff_t *ppos);
 483 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 484                              size_t cnt, loff_t *ppos);
 485 int ftrace_regex_release(struct inode *inode, struct file *file);
 486
 487 void __init
 488 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
 489
 490 /* defined in arch */
 491 extern int ftrace_ip_converted(unsigned long ip);
 492 extern int ftrace_dyn_arch_init(void);
 493 extern void ftrace_replace_code(int enable);
 494 extern int ftrace_update_ftrace_func(ftrace_func_t func);
 495 extern void ftrace_caller(void);
 496 extern void ftrace_regs_caller(void);
 497 extern void ftrace_call(void);
 498 extern void ftrace_regs_call(void);
 499 extern void mcount_call(void);
 500
 501 void ftrace_modify_all_code(int command);
 502
 503 #ifndef FTRACE_ADDR
 504 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
 505 #endif
 506
 507 #ifndef FTRACE_GRAPH_ADDR
 508 #define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller)
 509 #endif
 510
 511 #ifndef FTRACE_REGS_ADDR
 512 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 513 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller)
 514 #else
 515 # define FTRACE_REGS_ADDR FTRACE_ADDR
 516 #endif
 517 #endif
 518
 519 /*
 520  * If an arch would like functions that are only traced
 521  * by the function graph tracer to jump directly to its own
 522  * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR
 523  * to be that address to jump to.
 524  */
 525 #ifndef FTRACE_GRAPH_TRAMP_ADDR
 526 #define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0)
 527 #endif
 528
 529 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 530 extern void ftrace_graph_caller(void);
 531 extern int ftrace_enable_ftrace_graph_caller(void);
 532 extern int ftrace_disable_ftrace_graph_caller(void);
 533 #else
 534 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
 535 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
 536 #endif
 537
 538 /**
 539  * ftrace_make_nop - convert code into nop
 540  * @mod: module structure if called by module load initialization
 541  * @rec: the mcount call site record
 542  * @addr: the address that the call site should be calling
 543  *
 544  * This is a very sensitive operation and great care needs
 545  * to be taken by the arch.  The operation should carefully
 546  * read the location, check to see if what is read is indeed
 547  * what we expect it to be, and then on success of the compare,
 548  * it should write to the location.
 549  *
 550  * The code segment at @rec->ip should be a caller to @addr
 551  *
 552  * Return must be:
 553  *  0 on success
 554  *  -EFAULT on error reading the location
 555  *  -EINVAL on a failed compare of the contents
 556  *  -EPERM  on error writing to the location
 557  * Any other value will be considered a failure.
 558  */
 559 extern int ftrace_make_nop(struct module *mod,
 560                            struct dyn_ftrace *rec, unsigned long addr);
 561
 562 /**
 563  * ftrace_make_call - convert a nop call site into a call to addr
 564  * @rec: the mcount call site record
 565  * @addr: the address that the call site should call
 566  *
 567  * This is a very sensitive operation and great care needs
 568  * to be taken by the arch.  The operation should carefully
 569  * read the location, check to see if what is read is indeed
 570  * what we expect it to be, and then on success of the compare,
 571  * it should write to the location.
 572  *
 573  * The code segment at @rec->ip should be a nop
 574  *
 575  * Return must be:
 576  *  0 on success
 577  *  -EFAULT on error reading the location
 578  *  -EINVAL on a failed compare of the contents
 579  *  -EPERM  on error writing to the location
 580  * Any other value will be considered a failure.
 581  */
 582 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
 583
 584 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 585 /**
 586  * ftrace_modify_call - convert from one addr to another (no nop)
 587  * @rec: the mcount call site record
 588  * @old_addr: the address expected to be currently called to
 589  * @addr: the address to change to
 590  *
 591  * This is a very sensitive operation and great care needs
 592  * to be taken by the arch.  The operation should carefully
 593  * read the location, check to see if what is read is indeed
 594  * what we expect it to be, and then on success of the compare,
 595  * it should write to the location.
 596  *
 597  * The code segment at @rec->ip should be a caller to @old_addr
 598  *
 599  * Return must be:
 600  *  0 on success
 601  *  -EFAULT on error reading the location
 602  *  -EINVAL on a failed compare of the contents
 603  *  -EPERM  on error writing to the location
 604  * Any other value will be considered a failure.
 605  */
 606 extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 607                               unsigned long addr);
 608 #else
 609 /* Should never be called */
 610 static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 611                                      unsigned long addr)
 612 {
 613         return -EINVAL;
 614 }
 615 #endif
 616
 617 /* May be defined in arch */
 618 extern int ftrace_arch_read_dyn_info(char *buf, int size);
 619
 620 extern int skip_trace(unsigned long ip);
 621 extern void ftrace_module_init(struct module *mod);
 622 extern void ftrace_module_enable(struct module *mod);
 623 extern void ftrace_release_mod(struct module *mod);
 624
 625 extern void ftrace_disable_daemon(void);
 626 extern void ftrace_enable_daemon(void);
 627 #else /* CONFIG_DYNAMIC_FTRACE */
 628 static inline int skip_trace(unsigned long ip) { return 0; }
 629 static inline int ftrace_force_update(void) { return 0; }
 630 static inline void ftrace_disable_daemon(void) { }
 631 static inline void ftrace_enable_daemon(void) { }
 632 static inline void ftrace_module_init(struct module *mod) { }
 633 static inline void ftrace_module_enable(struct module *mod) { }
 634 static inline void ftrace_release_mod(struct module *mod) { }
 635 static inline int ftrace_text_reserved(const void *start, const void *end)
 636 {
 637         return 0;
 638 }
 639 static inline unsigned long ftrace_location(unsigned long ip)
 640 {
 641         return 0;
 642 }
 643
 644 /*
 645  * Again users of functions that have ftrace_ops may not
 646  * have them defined when ftrace is not enabled, but these
 647  * functions may still be called. Use a macro instead of inline.
 648  */
 649 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
 650 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
 651 #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; })
 652 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
 653 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
 654 #define ftrace_free_filter(ops) do { } while (0)
 655 #define ftrace_ops_set_global_filter(ops) do { } while (0)
 656
 657 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 658                             size_t cnt, loff_t *ppos) { return -ENODEV; }
 659 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 660                              size_t cnt, loff_t *ppos) { return -ENODEV; }
 661 static inline int
 662 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
 663
 664 static inline bool is_ftrace_trampoline(unsigned long addr)
 665 {
 666         return false;
 667 }
 668 #endif /* CONFIG_DYNAMIC_FTRACE */
 669
 670 /* totally disable ftrace - can not re-enable after this */
 671 void ftrace_kill(void);
 672
 673 static inline void tracer_disable(void)
 674 {
 675 #ifdef CONFIG_FUNCTION_TRACER
 676         ftrace_enabled = 0;
 677 #endif
 678 }
 679
 680 /*
 681  * Ftrace disable/restore without lock. Some synchronization mechanism
 682  * must be used to prevent ftrace_enabled to be changed between
 683  * disable/restore.
 684  */
 685 static inline int __ftrace_enabled_save(void)
 686 {
 687 #ifdef CONFIG_FUNCTION_TRACER
 688         int saved_ftrace_enabled = ftrace_enabled;
 689         ftrace_enabled = 0;
 690         return saved_ftrace_enabled;
 691 #else
 692         return 0;
 693 #endif
 694 }
 695
 696 static inline void __ftrace_enabled_restore(int enabled)
 697 {
 698 #ifdef CONFIG_FUNCTION_TRACER
 699         ftrace_enabled = enabled;
 700 #endif
 701 }
 702
 703 /* All archs should have this, but we define it for consistency */
 704 #ifndef ftrace_return_address0
 705 # define ftrace_return_address0 __builtin_return_address(0)
 706 #endif
 707
 708 /* Archs may use other ways for ADDR1 and beyond */
 709 #ifndef ftrace_return_address
 710 # ifdef CONFIG_FRAME_POINTER
 711 #  define ftrace_return_address(n) __builtin_return_address(n)
 712 # else
 713 #  define ftrace_return_address(n) 0UL
 714 # endif
 715 #endif
 716
 717 #define CALLER_ADDR0 ((unsigned long)ftrace_return_address0)
 718 #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1))
 719 #define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2))
 720 #define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3))
 721 #define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4))
 722 #define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5))
 723 #define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6))
 724
 725 static inline unsigned long get_lock_parent_ip(void)
 726 {
 727         unsigned long addr = CALLER_ADDR0;
 728
 729         if (!in_lock_functions(addr))
 730                 return addr;
 731         addr = CALLER_ADDR1;
 732         if (!in_lock_functions(addr))
 733                 return addr;
 734         return CALLER_ADDR2;
 735 }
 736
 737 #ifdef CONFIG_IRQSOFF_TRACER
 738   extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
 739   extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
 740 #else
 741   static inline void time_hardirqs_on(unsigned long a0, unsigned long a1) { }
 742   static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { }
 743 #endif
 744
 745 #ifdef CONFIG_PREEMPT_TRACER
 746   extern void trace_preempt_on(unsigned long a0, unsigned long a1);
 747   extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 748 #else
 749 /*
 750  * Use defines instead of static inlines because some arches will make code out
 751  * of the CALLER_ADDR, when we really want these to be a real nop.
 752  */
 753 # define trace_preempt_on(a0, a1) do { } while (0)
 754 # define trace_preempt_off(a0, a1) do { } while (0)
 755 #endif
 756
 757 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 758 extern void ftrace_init(void);
 759 #else
 760 static inline void ftrace_init(void) { }
 761 #endif
 762
 763 /*
 764  * Structure that defines an entry function trace.
 765  * It's already packed but the attribute "packed" is needed
 766  * to remove extra padding at the end.
 767  */
 768 struct ftrace_graph_ent {
 769         unsigned long func; /* Current function */
 770         int depth;
 771 } __packed;
 772
 773 /*
 774  * Structure that defines a return function trace.
 775  * It's already packed but the attribute "packed" is needed
 776  * to remove extra padding at the end.
 777  */
 778 struct ftrace_graph_ret {
 779         unsigned long func; /* Current function */
 780         /* Number of functions that overran the depth limit for current task */
 781         unsigned long overrun;
 782         unsigned long long calltime;
 783         unsigned long long rettime;
 784         int depth;
 785 } __packed;
 786
 787 /* Type of the callback handlers for tracing function graph*/
 788 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
 789 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
 790
 791 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 792
 793 /* for init task */
 794 #define INIT_FTRACE_GRAPH               .ret_stack = NULL,
 795
 796 /*
 797  * Stack of return addresses for functions
 798  * of a thread.
 799  * Used in struct thread_info
 800  */
 801 struct ftrace_ret_stack {
 802         unsigned long ret;
 803         unsigned long func;
 804         unsigned long long calltime;
 805 #ifdef CONFIG_FUNCTION_PROFILER
 806         unsigned long long subtime;
 807 #endif
 808 #ifdef HAVE_FUNCTION_GRAPH_FP_TEST
 809         unsigned long fp;
 810 #endif
 811 #ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
 812         unsigned long *retp;
 813 #endif
 814 };
 815
 816 /*
 817  * Primary handler of a function return.
 818  * It relays on ftrace_return_to_handler.
 819  * Defined in entry_32/64.S
 820  */
 821 extern void return_to_handler(void);
 822
 823 extern int
 824 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
 825                          unsigned long frame_pointer, unsigned long *retp);
 826
 827 unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
 828                                     unsigned long ret, unsigned long *retp);
 829
 830 /*
 831  * Sometimes we don't want to trace a function with the function
 832  * graph tracer but we want them to keep traced by the usual function
 833  * tracer if the function graph tracer is not configured.
 834  */
 835 #define __notrace_funcgraph             notrace
 836
 837 #define FTRACE_NOTRACE_DEPTH 65536
 838 #define FTRACE_RETFUNC_DEPTH 50
 839 #define FTRACE_RETSTACK_ALLOC_SIZE 32
 840 extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 841                                 trace_func_graph_ent_t entryfunc);
 842
 843 extern bool ftrace_graph_is_dead(void);
 844 extern void ftrace_graph_stop(void);
 845
 846 /* The current handlers in use */
 847 extern trace_func_graph_ret_t ftrace_graph_return;
 848 extern trace_func_graph_ent_t ftrace_graph_entry;
 849
 850 extern void unregister_ftrace_graph(void);
 851
 852 extern void ftrace_graph_init_task(struct task_struct *t);
 853 extern void ftrace_graph_exit_task(struct task_struct *t);
 854 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
 855
 856 static inline int task_curr_ret_stack(struct task_struct *t)
 857 {
 858         return t->curr_ret_stack;
 859 }
 860
 861 static inline void pause_graph_tracing(void)
 862 {
 863         atomic_inc(&current->tracing_graph_pause);
 864 }
 865
 866 static inline void unpause_graph_tracing(void)
 867 {
 868         atomic_dec(&current->tracing_graph_pause);
 869 }
 870 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */
 871
 872 #define __notrace_funcgraph
 873 #define INIT_FTRACE_GRAPH
 874
 875 static inline void ftrace_graph_init_task(struct task_struct *t) { }
 876 static inline void ftrace_graph_exit_task(struct task_struct *t) { }
 877 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
 878
 879 static inline int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 880                           trace_func_graph_ent_t entryfunc)
 881 {
 882         return -1;
 883 }
 884 static inline void unregister_ftrace_graph(void) { }
 885
 886 static inline int task_curr_ret_stack(struct task_struct *tsk)
 887 {
 888         return -1;
 889 }
 890
 891 static inline unsigned long
 892 ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret,
 893                       unsigned long *retp)
 894 {
 895         return ret;
 896 }
 897
 898 static inline void pause_graph_tracing(void) { }
 899 static inline void unpause_graph_tracing(void) { }
 900 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 901
 902 #ifdef CONFIG_TRACING
 903
 904 /* flags for current->trace */
 905 enum {
 906         TSK_TRACE_FL_TRACE_BIT  = 0,
 907         TSK_TRACE_FL_GRAPH_BIT  = 1,
 908 };
 909 enum {
 910         TSK_TRACE_FL_TRACE      = 1 << TSK_TRACE_FL_TRACE_BIT,
 911         TSK_TRACE_FL_GRAPH      = 1 << TSK_TRACE_FL_GRAPH_BIT,
 912 };
 913
 914 static inline void set_tsk_trace_trace(struct task_struct *tsk)
 915 {
 916         set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 917 }
 918
 919 static inline void clear_tsk_trace_trace(struct task_struct *tsk)
 920 {
 921         clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 922 }
 923
 924 static inline int test_tsk_trace_trace(struct task_struct *tsk)
 925 {
 926         return tsk->trace & TSK_TRACE_FL_TRACE;
 927 }
 928
 929 static inline void set_tsk_trace_graph(struct task_struct *tsk)
 930 {
 931         set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 932 }
 933
 934 static inline void clear_tsk_trace_graph(struct task_struct *tsk)
 935 {
 936         clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 937 }
 938
 939 static inline int test_tsk_trace_graph(struct task_struct *tsk)
 940 {
 941         return tsk->trace & TSK_TRACE_FL_GRAPH;
 942 }
 943
 944 enum ftrace_dump_mode;
 945
 946 extern enum ftrace_dump_mode ftrace_dump_on_oops;
 947 extern int tracepoint_printk;
 948
 949 extern void disable_trace_on_warning(void);
 950 extern int __disable_trace_on_warning;
 951
 952 #ifdef CONFIG_PREEMPT
 953 #define INIT_TRACE_RECURSION            .trace_recursion = 0,
 954 #endif
 955
 956 int tracepoint_printk_sysctl(struct ctl_table *table, int write,
 957                              void __user *buffer, size_t *lenp,
 958                              loff_t *ppos);
 959
 960 #else /* CONFIG_TRACING */
 961 static inline void  disable_trace_on_warning(void) { }
 962 #endif /* CONFIG_TRACING */
 963
 964 #ifndef INIT_TRACE_RECURSION
 965 #define INIT_TRACE_RECURSION
 966 #endif
 967
 968 #ifdef CONFIG_FTRACE_SYSCALLS
 969
 970 unsigned long arch_syscall_addr(int nr);
 971
 972 #endif /* CONFIG_FTRACE_SYSCALLS */
 973
 974 #endif /* _LINUX_FTRACE_H */