linux/tools/perf/util/probe-event.h
Ravi Bangoria 99e608b595 perf probe ppc64le: Fix probe location when using DWARF
Powerpc has Global Entry Point and Local Entry Point for functions.  LEP
catches call from both the GEP and the LEP. Symbol table of ELF contains
GEP and Offset from which we can calculate LEP, but debuginfo does not
have LEP info.

Currently, perf prioritize symbol table over dwarf to probe on LEP for
ppc64le. But when user tries to probe with function parameter, we fall
back to using dwarf(i.e. GEP) and when function called via LEP, probe
will never hit.

For example:

  $ objdump -d vmlinux
    ...
    do_sys_open():
    c0000000002eb4a0:       e8 00 4c 3c     addis   r2,r12,232
    c0000000002eb4a4:       60 00 42 38     addi    r2,r2,96
    c0000000002eb4a8:       a6 02 08 7c     mflr    r0
    c0000000002eb4ac:       d0 ff 41 fb     std     r26,-48(r1)

  $ sudo ./perf probe do_sys_open
  $ sudo cat /sys/kernel/debug/tracing/kprobe_events
    p:probe/do_sys_open _text+3060904

  $ sudo ./perf probe 'do_sys_open filename:string'
  $ sudo cat /sys/kernel/debug/tracing/kprobe_events
    p:probe/do_sys_open _text+3060896 filename_string=+0(%gpr4):string

For second case, perf probed on GEP. So when function will be called via
LEP, probe won't hit.

  $ sudo ./perf record -a -e probe:do_sys_open ls
    [ perf record: Woken up 1 times to write data ]
    [ perf record: Captured and wrote 0.195 MB perf.data ]

To resolve this issue, let's not prioritize symbol table, let perf
decide what it wants to use. Perf is already converting GEP to LEP when
it uses symbol table. When perf uses debuginfo, let it find LEP offset
form symbol table. This way we fall back to probe on LEP for all cases.

After patch:

  $ sudo ./perf probe 'do_sys_open filename:string'
  $ sudo cat /sys/kernel/debug/tracing/kprobe_events
    p:probe/do_sys_open _text+3060904 filename_string=+0(%gpr4):string

  $ sudo ./perf record -a -e probe:do_sys_open ls
    [ perf record: Woken up 1 times to write data ]
    [ perf record: Captured and wrote 0.197 MB perf.data (11 samples) ]

Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1470723805-5081-2-git-send-email-ravi.bangoria@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-08-09 12:14:29 -03:00

181 lines
5.8 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;
bool cache;
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 sdt; /* SDT/cached event flag */
bool uprobes; /* Uprobe event flag */
char *target; /* Target binary */
struct perf_probe_arg *args; /* Arguments */
struct probe_trace_event *tevs;
int ntevs;
};
/* 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;
int init_probe_symbol_maps(bool user_only);
void exit_probe_symbol_maps(void);
/* Command string to events */
int parse_perf_probe_command(const char *cmd, struct perf_probe_event *pev);
int parse_probe_trace_command(const char *cmd, struct probe_trace_event *tev);
/* Events to command string */
char *synthesize_perf_probe_command(struct perf_probe_event *pev);
char *synthesize_probe_trace_command(struct probe_trace_event *tev);
char *synthesize_perf_probe_arg(struct perf_probe_arg *pa);
char *synthesize_perf_probe_point(struct perf_probe_point *pp);
int perf_probe_event__copy(struct perf_probe_event *dst,
struct perf_probe_event *src);
/* Check the perf_probe_event needs debuginfo */
bool perf_probe_event_need_dwarf(struct perf_probe_event *pev);
/* Release event contents */
void clear_perf_probe_event(struct perf_probe_event *pev);
void clear_probe_trace_event(struct probe_trace_event *tev);
/* Command string to line-range */
int parse_line_range_desc(const char *cmd, struct line_range *lr);
/* Release line range members */
void line_range__clear(struct line_range *lr);
/* Initialize line range */
int line_range__init(struct line_range *lr);
int add_perf_probe_events(struct perf_probe_event *pevs, int npevs);
int convert_perf_probe_events(struct perf_probe_event *pevs, int npevs);
int apply_perf_probe_events(struct perf_probe_event *pevs, int npevs);
void cleanup_perf_probe_events(struct perf_probe_event *pevs, int npevs);
int del_perf_probe_events(struct strfilter *filter);
int show_perf_probe_event(const char *group, const char *event,
struct perf_probe_event *pev,
const char *module, bool use_stdout);
int show_perf_probe_events(struct strfilter *filter);
int show_line_range(struct line_range *lr, const char *module, bool user);
int show_available_vars(struct perf_probe_event *pevs, int npevs,
struct strfilter *filter);
int show_available_funcs(const char *module, struct strfilter *filter, bool user);
void arch__fix_tev_from_maps(struct perf_probe_event *pev,
struct probe_trace_event *tev, struct map *map,
struct symbol *sym);
/* 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);
struct map *get_target_map(const char *target, bool user);
void arch__post_process_probe_trace_events(struct perf_probe_event *pev,
int ntevs);
#endif /*_PROBE_EVENT_H */