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
  78 enum {
  79         FTRACE_FL_FREE          = (1 << 0),
  80         FTRACE_FL_FAILED        = (1 << 1),
  81         FTRACE_FL_FILTER        = (1 << 2),
  82         FTRACE_FL_ENABLED       = (1 << 3),
  83         FTRACE_FL_NOTRACE       = (1 << 4),
  84         FTRACE_FL_CONVERTED     = (1 << 5),
  85         FTRACE_FL_FROZEN        = (1 << 6),
  86 };
  87
  88 struct dyn_ftrace {
  89         struct list_head        list;
  90         unsigned long           ip; /* address of mcount call-site */
  91         unsigned long           flags;
  92 };
  93
  94 int ftrace_force_update(void);
  95 void ftrace_set_filter(unsigned char *buf, int len, int reset);
  96
  97 /* defined in arch */
  98 extern int ftrace_ip_converted(unsigned long ip);
  99 extern unsigned char *ftrace_nop_replace(void);
 100 extern unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr);
 101 extern int ftrace_dyn_arch_init(void *data);
 102 extern int ftrace_update_ftrace_func(ftrace_func_t func);
 103 extern void ftrace_caller(void);
 104 extern void ftrace_call(void);
 105 extern void mcount_call(void);
 106
 107 /* May be defined in arch */
 108 extern int ftrace_arch_read_dyn_info(char *buf, int size);
 109
 110 /**
 111  * ftrace_modify_code - modify code segment
 112  * @ip: the address of the code segment
 113  * @old_code: the contents of what is expected to be there
 114  * @new_code: the code to patch in
 115  *
 116  * This is a very sensitive operation and great care needs
 117  * to be taken by the arch.  The operation should carefully
 118  * read the location, check to see if what is read is indeed
 119  * what we expect it to be, and then on success of the compare,
 120  * it should write to the location.
 121  *
 122  * Return must be:
 123  *  0 on success
 124  *  -EFAULT on error reading the location
 125  *  -EINVAL on a failed compare of the contents
 126  *  -EPERM  on error writing to the location
 127  * Any other value will be considered a failure.
 128  */
 129 extern int ftrace_modify_code(unsigned long ip, unsigned char *old_code,
 130                               unsigned char *new_code);
 131
 132 extern int skip_trace(unsigned long ip);
 133
 134 extern void ftrace_release(void *start, unsigned long size);
 135
 136 extern void ftrace_disable_daemon(void);
 137 extern void ftrace_enable_daemon(void);
 138
 139 #else
 140 # define skip_trace(ip)                         ({ 0; })
 141 # define ftrace_force_update()                  ({ 0; })
 142 # define ftrace_set_filter(buf, len, reset)     do { } while (0)
 143 # define ftrace_disable_daemon()                do { } while (0)
 144 # define ftrace_enable_daemon()                 do { } while (0)
 145 static inline void ftrace_release(void *start, unsigned long size) { }
 146 #endif /* CONFIG_DYNAMIC_FTRACE */
 147
 148 /* totally disable ftrace - can not re-enable after this */
 149 void ftrace_kill(void);
 150
 151 static inline void tracer_disable(void)
 152 {
 153 #ifdef CONFIG_FUNCTION_TRACER
 154         ftrace_enabled = 0;
 155 #endif
 156 }
 157
 158 /*
 159  * Ftrace disable/restore without lock. Some synchronization mechanism
 160  * must be used to prevent ftrace_enabled to be changed between
 161  * disable/restore.
 162  */
 163 static inline int __ftrace_enabled_save(void)
 164 {
 165 #ifdef CONFIG_FUNCTION_TRACER
 166         int saved_ftrace_enabled = ftrace_enabled;
 167         ftrace_enabled = 0;
 168         return saved_ftrace_enabled;
 169 #else
 170         return 0;
 171 #endif
 172 }
 173
 174 static inline void __ftrace_enabled_restore(int enabled)
 175 {
 176 #ifdef CONFIG_FUNCTION_TRACER
 177         ftrace_enabled = enabled;
 178 #endif
 179 }
 180
 181 #ifdef CONFIG_FRAME_POINTER
 182 /* TODO: need to fix this for ARM */
 183 # define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
 184 # define CALLER_ADDR1 ((unsigned long)__builtin_return_address(1))
 185 # define CALLER_ADDR2 ((unsigned long)__builtin_return_address(2))
 186 # define CALLER_ADDR3 ((unsigned long)__builtin_return_address(3))
 187 # define CALLER_ADDR4 ((unsigned long)__builtin_return_address(4))
 188 # define CALLER_ADDR5 ((unsigned long)__builtin_return_address(5))
 189 # define CALLER_ADDR6 ((unsigned long)__builtin_return_address(6))
 190 #else
 191 # define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
 192 # define CALLER_ADDR1 0UL
 193 # define CALLER_ADDR2 0UL
 194 # define CALLER_ADDR3 0UL
 195 # define CALLER_ADDR4 0UL
 196 # define CALLER_ADDR5 0UL
 197 # define CALLER_ADDR6 0UL
 198 #endif
 199
 200 #ifdef CONFIG_IRQSOFF_TRACER
 201   extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
 202   extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
 203 #else
 204 # define time_hardirqs_on(a0, a1)               do { } while (0)
 205 # define time_hardirqs_off(a0, a1)              do { } while (0)
 206 #endif
 207
 208 #ifdef CONFIG_PREEMPT_TRACER
 209   extern void trace_preempt_on(unsigned long a0, unsigned long a1);
 210   extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 211 #else
 212 # define trace_preempt_on(a0, a1)               do { } while (0)
 213 # define trace_preempt_off(a0, a1)              do { } while (0)
 214 #endif
 215
 216 #ifdef CONFIG_TRACING
 217 extern int ftrace_dump_on_oops;
 218
 219 extern void
 220 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
 221
 222 /**
 223  * ftrace_printk - printf formatting in the ftrace buffer
 224  * @fmt: the printf format for printing
 225  *
 226  * Note: __ftrace_printk is an internal function for ftrace_printk and
 227  *       the @ip is passed in via the ftrace_printk macro.
 228  *
 229  * This function allows a kernel developer to debug fast path sections
 230  * that printk is not appropriate for. By scattering in various
 231  * printk like tracing in the code, a developer can quickly see
 232  * where problems are occurring.
 233  *
 234  * This is intended as a debugging tool for the developer only.
 235  * Please refrain from leaving ftrace_printks scattered around in
 236  * your code.
 237  */
 238 # define ftrace_printk(fmt...) __ftrace_printk(_THIS_IP_, fmt)
 239 extern int
 240 __ftrace_printk(unsigned long ip, const char *fmt, ...)
 241         __attribute__ ((format (printf, 2, 3)));
 242 extern void ftrace_dump(void);
 243 #else
 244 static inline void
 245 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { }
 246 static inline int
 247 ftrace_printk(const char *fmt, ...) __attribute__ ((format (printf, 1, 0)));
 248
 249 static inline int
 250 ftrace_printk(const char *fmt, ...)
 251 {
 252         return 0;
 253 }
 254 static inline void ftrace_dump(void) { }
 255 #endif
 256
 257 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 258 extern void ftrace_init(void);
 259 extern void ftrace_init_module(unsigned long *start, unsigned long *end);
 260 #else
 261 static inline void ftrace_init(void) { }
 262 static inline void
 263 ftrace_init_module(unsigned long *start, unsigned long *end) { }
 264 #endif
 265
 266
 267 /*
 268  * Structure which defines the trace of an initcall.
 269  * You don't have to fill the func field since it is
 270  * only used internally by the tracer.
 271  */
 272 struct boot_trace {
 273         pid_t                   caller;
 274         char                    func[KSYM_NAME_LEN];
 275         int                     result;
 276         unsigned long long      duration;               /* usecs */
 277         ktime_t                 calltime;
 278         ktime_t                 rettime;
 279 };
 280
 281 #ifdef CONFIG_BOOT_TRACER
 282 /* Append the trace on the ring-buffer */
 283 extern void trace_boot(struct boot_trace *it, initcall_t fn);
 284
 285 /* Tells the tracer that smp_pre_initcall is finished.
 286  * So we can start the tracing
 287  */
 288 extern void start_boot_trace(void);
 289
 290 /* Resume the tracing of other necessary events
 291  * such as sched switches
 292  */
 293 extern void enable_boot_trace(void);
 294
 295 /* Suspend this tracing. Actually, only sched_switches tracing have
 296  * to be suspended. Initcalls doesn't need it.)
 297  */
 298 extern void disable_boot_trace(void);
 299 #else
 300 static inline void trace_boot(struct boot_trace *it, initcall_t fn) { }
 301 static inline void start_boot_trace(void) { }
 302 static inline void enable_boot_trace(void) { }
 303 static inline void disable_boot_trace(void) { }
 304 #endif
 305
 306
 307
 308 #endif /* _LINUX_FTRACE_H */