一：tracing目录文件以及创建的代码
root@memory-153:/sys/kernel/debug/tracing# ls
available_events options stack_trace_filter
available_filter_functions per_cpu trace
available_tracers printk_formats trace_clock
buffer_size_kb README trace_marker
buffer_total_size_kb saved_cmdlines trace_options
current_tracer saved_cmdlines_size trace_pipe
dyn_ftrace_total_info set_event trace_stat
enabled_functions set_ftrace_filter tracing_cpumask
events set_ftrace_notrace tracing_max_latency
free_buffer set_ftrace_pid tracing_on
function_profile_enabled set_graph_function tracing_thresh
instances set_graph_notrace uprobe_events
kprobe_events snapshot uprobe_profile
kprobe_profile stack_max_size
max_graph_depth stack_trace
root@memory-153:/sys/kernel/debug/tracing# cat /boot/System.map-3.12.1 | grep trace | grep __initcall
ffffffff81e482d0 t __initcall_trace_init_flags_sys_exitearly
ffffffff81e482d8 t __initcall_trace_init_flags_sys_enterearly
ffffffff81e482e8 t __initcall_register_trigger_all_cpu_backtraceearly
ffffffff81e48348 t __initcall_tracer_alloc_buffersearly
ffffffff81e48358 t __initcall_init_trace_printkearly
ffffffff81e48360 t __initcall_event_trace_memsetupearly
ffffffff81e48368 t __initcall_init_ftrace_syscallsearly
ffffffff81e48410 t __initcall_ftrace_mod_cmd_init1
ffffffff81e48418 t __initcall_init_function_trace1
ffffffff81e48420 t __initcall_init_wakeup_tracer1
ffffffff81e48428 t __initcall_init_graph_trace1
ffffffff81e48430 t __initcall_event_trace_enable1
ffffffff81e48978 t __initcall_ftrace_init_debugfs5
ffffffff81e48980 t __initcall_tracer_init_debugfs5
ffffffff81e48988 t __initcall_init_trace_printk_function_export5
ffffffff81e48998 t __initcall_event_trace_init5
ffffffff81e489a0 t __initcall_init_kprobe_trace5
ffffffff81e489a8 t __initcall_init_uprobe_trace5
ffffffff81e48c10 t __initcall_init_tracepoints6
ffffffff81e48c20 t __initcall_stack_trace_init6
ffffffff81e48c28 t __initcall_init_mmio_trace6
ffffffff81e48c30 t __initcall_init_blk_tracer6
ffffffff81e494a8 t __initcall_clear_boot_tracer7
ffffffff81e494b0 t __initcall_kdb_ftrace_register7
ftrace_init_debugfs 7
available_filter_functions enabled_functions set_ftrace_filter
set_ftrace_notrace set_graph_function set_ftrace_pid trace_stat function_profile_enabled
tracer_init_debugfs 20
tracing_cpumask trace_options trace trace_pipe buffer_size_kb buffer_total_size_kb free_buffer trace_marker trace_clock tracing_on snapshot per_cpu
available_tracers current_tracer tracing_max_latency tracing_thresh README saved_cmdlines dyn_ftrace_total_info instances options
init_trace_printk_function_export 1 printk_formats
event_trace_init 3
available_events set_event events
init_kprobe_trace 2
kprobe_events kprobe_profile
init_uprobe_trace 2
uprobe_events uprobe_profile
stack_trace_init 3
stack_max_size stack_trace stack_trace_filter
not found:
saved_cmdlines_size set_graph_notrace max_graph_depth
二：tracepoint, ftrace event, syscall trace
tracepoint
VMLINUX_SYMBOL(__start___tracepoints_ptrs) = .; \
*(__tracepoints_ptrs) /* Tracepoints: pointer array */\
VMLINUX_SYMBOL(__stop___tracepoints_ptrs) = .; \
*(__tracepoints_strings)/* Tracepoints: strings */ \
tracepoint.h
#define DEFINE_TRACE_FN(name, reg, unreg) \
static const char __tpstrtab_##name[] \
__attribute__((section("__tracepoints_strings"))) = #name; \
struct tracepoint __tracepoint_##name \
__attribute__((section("__tracepoints"))) = \
{ __tpstrtab_##name, STATIC_KEY_INIT_FALSE, reg, unreg, NULL };\
static struct tracepoint * const __tracepoint_ptr_##name __used \
__attribute__((section("__tracepoints_ptrs"))) = \
&__tracepoint_##name;
ftrace event
trace_types 所有tracer链表
nop tracer
function_trace
wakeup_tracer
wakeup_rt_tracer
mmio_tracer
blk_tracer
vmlinux.lds.h
#define FTRACE_EVENTS() . = ALIGN(8); \
VMLINUX_SYMBOL(__start_ftrace_events) = .; \
*(_ftrace_events) \
VMLINUX_SYMBOL(__stop_ftrace_events) = .;
ftrace.h
#undef DEFINE_EVENT_PRINT
#define DEFINE_EVENT_PRINT(template, call, proto, args, print) \
\
static const char print_fmt_##call[] = print; \
\
static struct ftrace_event_call __used event_##call = { \
.name = #call, \
.class = &event_class_##template, \
.event.funcs = &ftrace_event_type_funcs_##call, \
.print_fmt = print_fmt_##call, \
}; \
static struct ftrace_event_call __used \
__attribute__((section("_ftrace_events"))) *__event_##call = &event_##call
syscall trace
#define SYSCALL_TRACE_ENTER_EVENT(sname) \
static struct syscall_metadata __syscall_meta_##sname; \
static struct ftrace_event_call __used \
event_enter_##sname = { \
.name = "sys_enter"#sname, \
.class = &event_class_syscall_enter, \
.event.funcs = &enter_syscall_print_funcs, \
.data = (void *)&__syscall_meta_##sname,\
.flags = TRACE_EVENT_FL_CAP_ANY, \
}; \
static struct ftrace_event_call __used \
__attribute__((section("_ftrace_events"))) \
*__event_enter_##sname = &event_enter_##sname;
#define SYSCALL_TRACE_EXIT_EVENT(sname) \
static struct syscall_metadata __syscall_meta_##sname; \
static struct ftrace_event_call __used \
event_exit_##sname = { \
.name = "sys_exit"#sname, \
.class = &event_class_syscall_exit, \
.event.funcs = &exit_syscall_print_funcs, \
.data = (void *)&__syscall_meta_##sname,\
.flags = TRACE_EVENT_FL_CAP_ANY, \
}; \
static struct ftrace_event_call __used \
__attribute__((section("_ftrace_events"))) \
*__event_exit_##sname = &event_exit_##sname;
#define SYSCALL_METADATA(sname, nb, ...) \
static const char *types_##sname[] = { \
__MAP(nb,__SC_STR_TDECL,__VA_ARGS__) \
}; \
static const char *args_##sname[] = { \
__MAP(nb,__SC_STR_ADECL,__VA_ARGS__) \
}; \
SYSCALL_TRACE_ENTER_EVENT(sname); \
SYSCALL_TRACE_EXIT_EVENT(sname); \
static struct syscall_metadata __used \
__syscall_meta_##sname = { \
.name = "sys"#sname, \
.syscall_nr = -1, /* Filled in at boot */ \
.nb_args = nb, \
.types = nb ? types_##sname : NULL, \
.args = nb ? args_##sname : NULL, \
.enter_event = &event_enter_##sname, \
.exit_event = &event_exit_##sname, \
.enter_fields = LIST_HEAD_INIT(__syscall_meta_##sname.enter_fields), \
}; \
static struct syscall_metadata __used \
__attribute__((section("__syscalls_metadata"))) \
*__p_syscall_meta_##sname = &__syscall_meta_##sname;
#else
#define SYSCALL_METADATA(sname, nb, ...)
#endif
#define SYSCALL_DEFINE0(sname) \
SYSCALL_METADATA(_##sname, 0); \
asmlinkage long sys_##sname(void)
#define SYSCALL_DEFINE1(name, ...) SYSCALL_DEFINEx(1, _##name, __VA_ARGS__)
#define SYSCALL_DEFINE2(name, ...) SYSCALL_DEFINEx(2, _##name, __VA_ARGS__)
#define SYSCALL_DEFINE3(name, ...) SYSCALL_DEFINEx(3, _##name, __VA_ARGS__)
#define SYSCALL_DEFINE4(name, ...) SYSCALL_DEFINEx(4, _##name, __VA_ARGS__)
#define SYSCALL_DEFINE5(name, ...) SYSCALL_DEFINEx(5, _##name, __VA_ARGS__)
#define SYSCALL_DEFINE6(name, ...) SYSCALL_DEFINEx(6, _##name, __VA_ARGS__)
#define SYSCALL_DEFINEx(x, sname, ...) \
SYSCALL_METADATA(sname, x, __VA_ARGS__) \
__SYSCALL_DEFINEx(x, sname, __VA_ARGS__)