include/linux/ftrace.h

   1 #ifndef _LINUX_FTRACE_H
   2 #define _LINUX_FTRACE_H
   3
   4 #include <linux/linkage.h>
   5 #include <linux/fs.h>
   6 #include <linux/ktime.h>
   7 #include <linux/init.h>
   8 #include <linux/types.h>
   9 #include <linux/kallsyms.h>
  10
  11 #ifdef CONFIG_FUNCTION_TRACER
  12
  13 extern int ftrace_enabled;
  14 extern int
  15 ftrace_enable_sysctl(struct ctl_table *table, int write,
  16                      struct file *filp, void __user *buffer, size_t *lenp,
  17                      loff_t *ppos);
  18
  19 typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip);
  20
  21 struct ftrace_ops {
  22         ftrace_func_t     func;
  23         struct ftrace_ops *next;
  24 };
  25
  26 extern int function_trace_stop;
  27
  28 /**
  29  * ftrace_stop - stop function tracer.
  30  *
  31  * A quick way to stop the function tracer. Note this an on off switch,
  32  * it is not something that is recursive like preempt_disable.
  33  * This does not disable the calling of mcount, it only stops the
  34  * calling of functions from mcount.
  35  */
  36 static inline void ftrace_stop(void)
  37 {
  38         function_trace_stop = 1;
  39 }
  40
  41 /**
  42  * ftrace_start - start the function tracer.
  43  *
  44  * This function is the inverse of ftrace_stop. This does not enable
  45  * the function tracing if the function tracer is disabled. This only
  46  * sets the function tracer flag to continue calling the functions
  47  * from mcount.
  48  */
  49 static inline void ftrace_start(void)
  50 {
  51         function_trace_stop = 0;
  52 }
  53
  54 /*
  55  * The ftrace_ops must be a static and should also
  56  * be read_mostly.  These functions do modify read_mostly variables
  57  * so use them sparely. Never free an ftrace_op or modify the
  58  * next pointer after it has been registered. Even after unregistering
  59  * it, the next pointer may still be used internally.
  60  */
  61 int register_ftrace_function(struct ftrace_ops *ops);
  62 int unregister_ftrace_function(struct ftrace_ops *ops);
  63 void clear_ftrace_function(void);
  64
  65 extern void ftrace_stub(unsigned long a0, unsigned long a1);
  66
  67 #else /* !CONFIG_FUNCTION_TRACER */
  68 # define register_ftrace_function(ops) do { } while (0)
  69 # define unregister_ftrace_function(ops) do { } while (0)
  70 # define clear_ftrace_function(ops) do { } while (0)
  71 static inline void ftrace_kill(void) { }
  72 static inline void ftrace_stop(void) { }
  73 static inline void ftrace_start(void) { }
  74 #endif /* CONFIG_FUNCTION_TRACER */
  75
  76 #ifdef CONFIG_DYNAMIC_FTRACE
  77 enum {
  78         FTRACE_FL_FREE          = (1 << 0),
  79         FTRACE_FL_FAILED        = (1 << 1),
  80         FTRACE_FL_FILTER        = (1 << 2),
  81         FTRACE_FL_ENABLED       = (1 << 3),
  82         FTRACE_FL_NOTRACE       = (1 << 4),
  83         FTRACE_FL_CONVERTED     = (1 << 5),
  84         FTRACE_FL_FROZEN        = (1 << 6),
  85 };
  86
  87 struct dyn_ftrace {
  88         struct list_head        list;
  89         unsigned long           ip; /* address of mcount call-site */
  90         unsigned long           flags;
  91 };
  92
  93 int ftrace_force_update(void);
  94 void ftrace_set_filter(unsigned char *buf, int len, int reset);
  95
  96 /* defined in arch */
  97 extern int ftrace_ip_converted(unsigned long ip);
  98 extern unsigned char *ftrace_nop_replace(void);
  99 extern unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr);
 100 extern int ftrace_dyn_arch_init(void *data);
 101 extern int ftrace_update_ftrace_func(ftrace_func_t func);
 102 extern void ftrace_caller(void);
 103 extern void ftrace_call(void);
 104 extern void mcount_call(void);
 105
 106 /* May be defined in arch */
 107 extern int ftrace_arch_read_dyn_info(char *buf, int size);
 108
 109 /**
 110  * ftrace_modify_code - modify code segment
 111  * @ip: the address of the code segment
 112  * @old_code: the contents of what is expected to be there
 113  * @new_code: the code to patch in
 114  *
 115  * This is a very sensitive operation and great care needs
 116  * to be taken by the arch.  The operation should carefully
 117  * read the location, check to see if what is read is indeed
 118  * what we expect it to be, and then on success of the compare,
 119  * it should write to the location.
 120  *
 121  * Return must be:
 122  *  0 on success
 123  *  -EFAULT on error reading the location
 124  *  -EINVAL on a failed compare of the contents
 125  *  -EPERM  on error writing to the location
 126  * Any other value will be considered a failure.
 127  */
 128 extern int ftrace_modify_code(unsigned long ip, unsigned char *old_code,
 129                               unsigned char *new_code);
 130
 131 extern int skip_trace(unsigned long ip);
 132
 133 extern void ftrace_release(void *start, unsigned long size);
 134
 135 extern void ftrace_disable_daemon(void);
 136 extern void ftrace_enable_daemon(void);
 137 #else
 138 # define skip_trace(ip)                         ({ 0; })
 139 # define ftrace_force_update()                  ({ 0; })
 140 # define ftrace_set_filter(buf, len, reset)     do { } while (0)
 141 # define ftrace_disable_daemon()                do { } while (0)
 142 # define ftrace_enable_daemon()                 do { } while (0)
 143 static inline void ftrace_release(void *start, unsigned long size) { }
 144 #endif /* CONFIG_DYNAMIC_FTRACE */
 145
 146 /* totally disable ftrace - can not re-enable after this */
 147 void ftrace_kill(void);
 148
 149 static inline void tracer_disable(void)
 150 {
 151 #ifdef CONFIG_FUNCTION_TRACER
 152         ftrace_enabled = 0;
 153 #endif
 154 }
 155
 156 /*
 157  * Ftrace disable/restore without lock. Some synchronization mechanism
 158  * must be used to prevent ftrace_enabled to be changed between
 159  * disable/restore.
 160  */
 161 static inline int __ftrace_enabled_save(void)
 162 {
 163 #ifdef CONFIG_FUNCTION_TRACER
 164         int saved_ftrace_enabled = ftrace_enabled;
 165         ftrace_enabled = 0;
 166         return saved_ftrace_enabled;
 167 #else
 168         return 0;
 169 #endif
 170 }
 171
 172 static inline void __ftrace_enabled_restore(int enabled)
 173 {
 174 #ifdef CONFIG_FUNCTION_TRACER
 175         ftrace_enabled = enabled;
 176 #endif
 177 }
 178
 179 #ifdef CONFIG_FRAME_POINTER
 180 /* TODO: need to fix this for ARM */
 181 # define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
 182 # define CALLER_ADDR1 ((unsigned long)__builtin_return_address(1))
 183 # define CALLER_ADDR2 ((unsigned long)__builtin_return_address(2))
 184 # define CALLER_ADDR3 ((unsigned long)__builtin_return_address(3))
 185 # define CALLER_ADDR4 ((unsigned long)__builtin_return_address(4))
 186 # define CALLER_ADDR5 ((unsigned long)__builtin_return_address(5))
 187 # define CALLER_ADDR6 ((unsigned long)__builtin_return_address(6))
 188 #else
 189 # define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
 190 # define CALLER_ADDR1 0UL
 191 # define CALLER_ADDR2 0UL
 192 # define CALLER_ADDR3 0UL
 193 # define CALLER_ADDR4 0UL
 194 # define CALLER_ADDR5 0UL
 195 # define CALLER_ADDR6 0UL
 196 #endif
 197
 198 #ifdef CONFIG_IRQSOFF_TRACER
 199   extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
 200   extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
 201 #else
 202 # define time_hardirqs_on(a0, a1)               do { } while (0)
 203 # define time_hardirqs_off(a0, a1)              do { } while (0)
 204 #endif
 205
 206 #ifdef CONFIG_PREEMPT_TRACER
 207   extern void trace_preempt_on(unsigned long a0, unsigned long a1);
 208   extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 209 #else
 210 # define trace_preempt_on(a0, a1)               do { } while (0)
 211 # define trace_preempt_off(a0, a1)              do { } while (0)
 212 #endif
 213
 214 #ifdef CONFIG_TRACING
 215 extern int ftrace_dump_on_oops;
 216
 217 extern void tracing_start(void);
 218 extern void tracing_stop(void);
 219
 220 extern void
 221 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
 222
 223 /**
 224  * ftrace_printk - printf formatting in the ftrace buffer
 225  * @fmt: the printf format for printing
 226  *
 227  * Note: __ftrace_printk is an internal function for ftrace_printk and
 228  *       the @ip is passed in via the ftrace_printk macro.
 229  *
 230  * This function allows a kernel developer to debug fast path sections
 231  * that printk is not appropriate for. By scattering in various
 232  * printk like tracing in the code, a developer can quickly see
 233  * where problems are occurring.
 234  *
 235  * This is intended as a debugging tool for the developer only.
 236  * Please refrain from leaving ftrace_printks scattered around in
 237  * your code.
 238  */
 239 # define ftrace_printk(fmt...) __ftrace_printk(_THIS_IP_, fmt)
 240 extern int
 241 __ftrace_printk(unsigned long ip, const char *fmt, ...)
 242         __attribute__ ((format (printf, 2, 3)));
 243 extern void ftrace_dump(void);
 244 #else
 245 static inline void
 246 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { }
 247 static inline int
 248 ftrace_printk(const char *fmt, ...) __attribute__ ((format (printf, 1, 0)));
 249
 250 static inline void tracing_start(void) { }
 251 static inline void tracing_stop(void) { }
 252 static inline int
 253 ftrace_printk(const char *fmt, ...)
 254 {
 255         return 0;
 256 }
 257 static inline void ftrace_dump(void) { }
 258 #endif
 259
 260 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 261 extern void ftrace_init(void);
 262 extern void ftrace_init_module(unsigned long *start, unsigned long *end);
 263 #else
 264 static inline void ftrace_init(void) { }
 265 static inline void
 266 ftrace_init_module(unsigned long *start, unsigned long *end) { }
 267 #endif
 268
 269
 270 /*
 271  * Structure that defines a return function trace.
 272  */
 273 struct ftrace_retfunc {
 274         unsigned long ret; /* Return address */
 275         unsigned long func; /* Current function */
 276         unsigned long long calltime;
 277         unsigned long long rettime;
 278 };
 279
 280 #ifdef CONFIG_FUNCTION_RET_TRACER
 281 /* Type of a callback handler of tracing return function */
 282 typedef void (*trace_function_return_t)(struct ftrace_retfunc *);
 283
 284 extern void register_ftrace_return(trace_function_return_t func);
 285 /* The current handler in use */
 286 extern trace_function_return_t ftrace_function_return;
 287 extern void unregister_ftrace_return(void);
 288 #endif
 289
 290 #endif /* _LINUX_FTRACE_H */