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Message-ID: <1432456091-73384-11-git-send-email-hekuang@huawei.com>
Date: Sun, 24 May 2015 08:28:06 +0000
From: He Kuang <hekuang@...wei.com>
To: <wangnan0@...wei.com>, <paulus@...ba.org>,
<a.p.zijlstra@...llo.nl>, <mingo@...hat.com>, <acme@...nel.org>,
<namhyung@...nel.org>, <jolsa@...nel.org>, <ast@...mgrid.com>,
<masami.hiramatsu.pt@...achi.com>, <dsahern@...il.com>,
<brendan.d.gregg@...il.com>, <daniel@...earbox.net>
CC: <lizefan@...wei.com>, <linux-kernel@...r.kernel.org>
Subject: [RFC PATCH v2 10/15] perf bpf: Process debuginfo for generating bpf prologue
Process debuginfo for bpf prologue, the process function is copied and
modified from debuginfo__find_trace_events(), with a different callback
function for generating bpf prologue bytecode.
Signed-off-by: He Kuang <hekuang@...wei.com>
---
tools/perf/util/probe-event.c | 27 ++++++++++++
tools/perf/util/probe-event.h | 2 +
tools/perf/util/probe-finder.c | 93 ++++++++++++++++++++++++++++++++++++++++++
tools/perf/util/probe-finder.h | 4 ++
4 files changed, 126 insertions(+)
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 7f9f431..ccbf4d9 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -914,6 +914,33 @@ out:
return ret;
}
+int get_bpf_prologue(struct perf_probe_event *pev, char **result, int *count)
+{
+ int ret;
+ struct debuginfo *dinfo;
+ bool need_dwarf;
+
+ ret = init_symbol_maps(false);
+ if (ret < 0)
+ return ret;
+
+ need_dwarf = perf_probe_event_need_dwarf(pev);
+
+ dinfo = open_debuginfo(NULL, !need_dwarf);
+
+ if (!dinfo) {
+ if (need_dwarf)
+ return -ENOENT;
+ pr_debug("Could not open debuginfo. Try to use symbols.\n");
+ return 0;
+ }
+
+ pr_debug("Try to generate bpf prologue from debuginfo.\n");
+
+ ret = debuginfo__find_bpf_prologue(dinfo, pev, result, count);
+
+ return ret;
+}
#else /* !HAVE_DWARF_SUPPORT */
static int
diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
index 6c19395..3eb0183 100644
--- a/tools/perf/util/probe-event.h
+++ b/tools/perf/util/probe-event.h
@@ -106,6 +106,8 @@ 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);
+extern int get_bpf_prologue(struct perf_probe_event *pev,
+ char **result, int *count);
/* Check the perf_probe_event needs debuginfo */
extern bool perf_probe_event_need_dwarf(struct perf_probe_event *pev);
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 4de7649..6785eab 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -39,6 +39,7 @@
#include "util.h"
#include "symbol.h"
#include "probe-finder.h"
+#include <bpf/libbpf.h>
/* Kprobe tracer basic type is up to u64 */
#define MAX_BASIC_TYPE_BITS 64
@@ -1177,6 +1178,70 @@ static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
return n;
}
+static int generate_bpf_prologue(Dwarf_Die *sc_die, struct probe_finder *pf)
+{
+ struct trace_event_finder *tf =
+ container_of(pf, struct trace_event_finder, pf);
+ struct probe_trace_event *tev;
+ struct perf_probe_arg *args;
+ int ret, i;
+ Dwarf_Die vr_die;
+
+ /* Check number of tevs */
+ if (tf->ntevs == tf->max_tevs) {
+ pr_warning("Too many( > %d) probe point found.\n",
+ tf->max_tevs);
+ return -ERANGE;
+ }
+ tev = &tf->tevs[tf->ntevs++];
+
+ /* Expand special probe argument if exist */
+ args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
+ if (args == NULL)
+ return -ENOMEM;
+
+ ret = expand_probe_args(sc_die, pf, args);
+ if (ret <= 0)
+ goto end;
+
+ /* restrict nargs <= BPF_PROLOGUE_NRARGS_MAX */
+ if (ret > BPF_PROLOGUE_NRARGS_MAX)
+ ret = BPF_PROLOGUE_NRARGS_MAX;
+
+ tev->nargs = ret;
+ tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
+ if (tev->args == NULL) {
+ ret = -ENOMEM;
+ goto end;
+ }
+
+ /* Find each argument */
+ for (i = 0; i < tev->nargs; i++) {
+ pf->pvar = &args[i];
+ pf->tvar = &tev->args[i];
+
+ /* Search child die for local variables and parameters. */
+ if (!die_find_variable_at(sc_die, pf->pvar->var,
+ pf->addr, &vr_die)) {
+ /* Search again in global variables */
+ if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
+ 0, &vr_die)) {
+ pr_warning("Failed to find '%s' in this function.\n",
+ pf->pvar->var);
+ ret = -ENOENT;
+ }
+ }
+
+ if (ret >= 0)
+ ret = convert_variable(&vr_die, pf);
+ if (ret != 0)
+ break;
+ }
+end:
+ free(args);
+ return ret;
+}
+
/* Add a found probe point into trace event list */
static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
{
@@ -1261,6 +1326,34 @@ int debuginfo__find_trace_events(struct debuginfo *dbg,
return (ret < 0) ? ret : tf.ntevs;
}
+#define BPF_MAX_TEVS (1)
+int debuginfo__find_bpf_prologue(struct debuginfo *dbg,
+ struct perf_probe_event *pev,
+ char **result, int *count)
+{
+ struct trace_event_finder tf = {
+ .pf = {.pev = pev, .callback = generate_bpf_prologue},
+ .mod = dbg->mod, .max_tevs = BPF_MAX_TEVS};
+ struct probe_trace_event *tevs;
+ int ret;
+
+ /* Allocate result tevs array */
+ tevs = zalloc(sizeof(struct probe_trace_event) * BPF_MAX_TEVS);
+ if (tevs == NULL)
+ return -ENOMEM;
+
+ tf.tevs = tevs;
+ tf.ntevs = 0;
+
+ ret = debuginfo__find_probes(dbg, &tf.pf);
+
+ *result = NULL;
+ *count = 0;
+
+ free(tevs);
+ return ret;
+}
+
#define MAX_VAR_LEN 64
/* Collect available variables in this scope */
diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index f53553d..f046c63 100644
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -43,6 +43,10 @@ extern int debuginfo__find_trace_events(struct debuginfo *dbg,
struct probe_trace_event **tevs,
int max_tevs);
+extern int debuginfo__find_bpf_prologue(struct debuginfo *dbg,
+ struct perf_probe_event *pev,
+ char **result, int *count);
+
/* Find a perf_probe_point from debuginfo */
extern int debuginfo__find_probe_point(struct debuginfo *dbg,
unsigned long addr,
--
1.8.5.2
--
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