linux/tools/perf/util/probe-event.h
Wang Nan da15bd9df4 perf probe: Support probing at absolute address
It should be useful to allow 'perf probe' probe at absolute offset of a
target. For example, when (u)probing at a instruction of a shared object
in a embedded system where debuginfo is not avaliable but we know the
offset of that instruction by manually digging.

This patch enables following perf probe command syntax:

  # perf probe 0xffffffff811e6615

And

  # perf probe /lib/x86_64-linux-gnu/libc-2.19.so 0xeb860

In the above example, we don't need a anchor symbol, so it is possible
to compute absolute addresses using other methods and then use 'perf
probe' to create the probing points.

v1 -> v2:
  Drop the leading '+' in cmdline;
  Allow uprobing at offset 0x0;
  Improve 'perf probe -l' result when uprobe at area without debuginfo.

v2 -> v3:
  Split bugfix to a separated patch.

Test result:

  # perf probe 0xffffffff8119d175 %ax
  # perf probe sys_write %ax
  # perf probe /lib64/libc-2.18.so 0x0 %ax
  # perf probe /lib64/libc-2.18.so 0x5 %ax
  # perf probe /lib64/libc-2.18.so 0xd8e40 %ax
  # perf probe /lib64/libc-2.18.so __write %ax
  # perf probe /lib64/libc-2.18.so 0xd8e49 %ax
  # cat /sys/kernel/debug/tracing/uprobe_events

  p:probe_libc/abs_0 /lib64/libc-2.18.so:0x          (null) arg1=%ax
  p:probe_libc/abs_5 /lib64/libc-2.18.so:0x0000000000000005 arg1=%ax
  p:probe_libc/abs_d8e40 /lib64/libc-2.18.so:0x00000000000d8e40 arg1=%ax
  p:probe_libc/__write /lib64/libc-2.18.so:0x00000000000d8e40 arg1=%ax
  p:probe_libc/abs_d8e49 /lib64/libc-2.18.so:0x00000000000d8e49 arg1=%ax

  # cat /sys/kernel/debug/tracing/kprobe_events

  p:probe/abs_ffffffff8119d175 0xffffffff8119d175 arg1=%ax
  p:probe/sys_write _text+1692016 arg1=%ax

  # perf probe -l

  Failed to find debug information for address 5
    probe:abs_ffffffff8119d175 (on sys_write+5 with arg1)
    probe:sys_write      (on sys_write with arg1)
    probe_libc:__write   (on @unix/syscall-template.S:81 in /lib64/libc-2.18.so with arg1)
    probe_libc:abs_0     (on 0x0 in /lib64/libc-2.18.so with arg1)
    probe_libc:abs_5     (on 0x5 in /lib64/libc-2.18.so with arg1)
    probe_libc:abs_d8e40 (on @unix/syscall-template.S:81 in /lib64/libc-2.18.so with arg1)
    probe_libc:abs_d8e49 (on __GI___libc_write+9 in /lib64/libc-2.18.so with arg1)

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1440586666-235233-7-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-08-26 10:41:12 -03:00

164 lines
5.2 KiB
C

#ifndef _PROBE_EVENT_H
#define _PROBE_EVENT_H
#include <stdbool.h>
#include "intlist.h"
#include "strlist.h"
#include "strfilter.h"
/* Probe related configurations */
struct probe_conf {
bool show_ext_vars;
bool show_location_range;
bool force_add;
bool no_inlines;
int max_probes;
};
extern struct probe_conf probe_conf;
extern bool probe_event_dry_run;
/* kprobe-tracer and uprobe-tracer tracing point */
struct probe_trace_point {
char *realname; /* function real name (if needed) */
char *symbol; /* Base symbol */
char *module; /* Module name */
unsigned long offset; /* Offset from symbol */
unsigned long address; /* Actual address of the trace point */
bool retprobe; /* Return probe flag */
};
/* probe-tracer tracing argument referencing offset */
struct probe_trace_arg_ref {
struct probe_trace_arg_ref *next; /* Next reference */
long offset; /* Offset value */
};
/* kprobe-tracer and uprobe-tracer tracing argument */
struct probe_trace_arg {
char *name; /* Argument name */
char *value; /* Base value */
char *type; /* Type name */
struct probe_trace_arg_ref *ref; /* Referencing offset */
};
/* kprobe-tracer and uprobe-tracer tracing event (point + arg) */
struct probe_trace_event {
char *event; /* Event name */
char *group; /* Group name */
struct probe_trace_point point; /* Trace point */
int nargs; /* Number of args */
bool uprobes; /* uprobes only */
struct probe_trace_arg *args; /* Arguments */
};
/* Perf probe probing point */
struct perf_probe_point {
char *file; /* File path */
char *function; /* Function name */
int line; /* Line number */
bool retprobe; /* Return probe flag */
char *lazy_line; /* Lazy matching pattern */
unsigned long offset; /* Offset from function entry */
unsigned long abs_address; /* Absolute address of the point */
};
/* Perf probe probing argument field chain */
struct perf_probe_arg_field {
struct perf_probe_arg_field *next; /* Next field */
char *name; /* Name of the field */
long index; /* Array index number */
bool ref; /* Referencing flag */
};
/* Perf probe probing argument */
struct perf_probe_arg {
char *name; /* Argument name */
char *var; /* Variable name */
char *type; /* Type name */
struct perf_probe_arg_field *field; /* Structure fields */
};
/* Perf probe probing event (point + arg) */
struct perf_probe_event {
char *event; /* Event name */
char *group; /* Group name */
struct perf_probe_point point; /* Probe point */
int nargs; /* Number of arguments */
bool uprobes; /* Uprobe event flag */
char *target; /* Target binary */
struct perf_probe_arg *args; /* Arguments */
};
/* Line range */
struct line_range {
char *file; /* File name */
char *function; /* Function name */
int start; /* Start line number */
int end; /* End line number */
int offset; /* Start line offset */
char *path; /* Real path name */
char *comp_dir; /* Compile directory */
struct intlist *line_list; /* Visible lines */
};
/* List of variables */
struct variable_list {
struct probe_trace_point point; /* Actual probepoint */
struct strlist *vars; /* Available variables */
};
struct map;
/* Command string to events */
extern int parse_perf_probe_command(const char *cmd,
struct perf_probe_event *pev);
extern int parse_probe_trace_command(const char *cmd,
struct probe_trace_event *tev);
/* Events to command string */
extern char *synthesize_perf_probe_command(struct perf_probe_event *pev);
extern char *synthesize_probe_trace_command(struct probe_trace_event *tev);
extern int synthesize_perf_probe_arg(struct perf_probe_arg *pa, char *buf,
size_t len);
/* Check the perf_probe_event needs debuginfo */
extern bool perf_probe_event_need_dwarf(struct perf_probe_event *pev);
/* Release event contents */
extern void clear_perf_probe_event(struct perf_probe_event *pev);
extern void clear_probe_trace_event(struct probe_trace_event *tev);
/* Command string to line-range */
extern int parse_line_range_desc(const char *cmd, struct line_range *lr);
/* Release line range members */
extern void line_range__clear(struct line_range *lr);
/* Initialize line range */
extern int line_range__init(struct line_range *lr);
extern int add_perf_probe_events(struct perf_probe_event *pevs, int npevs);
extern int del_perf_probe_events(struct strfilter *filter);
extern int show_perf_probe_events(struct strfilter *filter);
extern int show_line_range(struct line_range *lr, const char *module,
bool user);
extern int show_available_vars(struct perf_probe_event *pevs, int npevs,
struct strfilter *filter);
extern int show_available_funcs(const char *module, struct strfilter *filter,
bool user);
bool arch__prefers_symtab(void);
void arch__fix_tev_from_maps(struct perf_probe_event *pev,
struct probe_trace_event *tev, struct map *map);
/* If there is no space to write, returns -E2BIG. */
int e_snprintf(char *str, size_t size, const char *format, ...)
__attribute__((format(printf, 3, 4)));
/* Maximum index number of event-name postfix */
#define MAX_EVENT_INDEX 1024
int copy_to_probe_trace_arg(struct probe_trace_arg *tvar,
struct perf_probe_arg *pvar);
#endif /*_PROBE_EVENT_H */