Process debuginfo for bpf prologue, the process function is copied and
modified from debuginfo__find_trace_events(), but use a different
callback function for generating bpf prologue bytecode.
Signed-off-by: He Kuang <heku...@huawei.com>
---
tools/perf/util/probe-event.c | 27 +++++++++++++
tools/perf/util/probe-event.h | 2 +
tools/perf/util/probe-finder.c | 90 ++++++++++++++++++++++++++++++++++++++++++
tools/perf/util/probe-finder.h | 4 ++
4 files changed, 123 insertions(+)
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index c307cd7..fbdda4d 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -906,6 +906,33 @@ 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 3b6c284..5a6b86e 100644
--- a/tools/perf/util/probe-event.h
+++ b/tools/perf/util/probe-event.h
@@ -115,6 +115,8 @@ extern int synthesize_probe_trace_arg_bpf(struct
probe_trace_arg *arg,
extern int synthesize_probe_trace_arg_bpf_begin(struct strbuf *buf);
extern int synthesize_probe_trace_arg_bpf_end(struct probe_trace_arg *arg,
struct strbuf *buf, int num);
+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 249e6cb..bfb7625 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -1164,6 +1164,71 @@ static int expand_probe_args(Dwarf_Die *sc_die, struct
probe_finder *pf,
return n;
}
+#define BPF_PROLOGUE_MAX_LEN (1024)
+static int generate_bpf_prologue(Dwarf_Die *sc_die, struct probe_finder *pf)
+{
+ struct perf_probe_arg *args;
+ int ret = 0, i;
+ Dwarf_Die vr_die;
+ struct strbuf buf;
+ int narg;
+
+ if (pf->tvar)
+ return -ERANGE;
+
+ pf->tvar = (struct probe_trace_arg *)
+ malloc(sizeof(struct probe_trace_arg));
+ if (pf->tvar == NULL)
+ return -ENOMEM;
+
+ /* Expand special probe argument if exist */
+ args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
+ if (args == NULL)
+ return -ENOMEM;
+
+ narg = expand_probe_args(sc_die, pf, args);
+ if (narg <= 0)
+ goto end;
+
+ strbuf_init(&buf, BPF_PROLOGUE_MAX_LEN);
+ synthesize_probe_trace_arg_bpf_begin(&buf);
+
+ /* Find each argument */
+ for (i = 0; i < narg; i++) {
+ pf->pvar = &args[i];
+
+ memset(pf->tvar, 0, sizeof(struct probe_trace_arg));
+ /* 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;
+
+ ret = synthesize_probe_trace_arg_bpf(pf->tvar, &buf, i);
+ if (ret)
+ goto end;
+ }
+
+ synthesize_probe_trace_arg_bpf_end(pf->tvar, &buf, narg);
+
+ pr_debug("bpf_prologue: insn num=%d\n", pf->tvar->insns_cnt);
+
+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)
{
@@ -1248,6 +1313,31 @@ int debuginfo__find_trace_events(struct debuginfo *dbg,
return (ret < 0) ? ret : tf.ntevs;
}
+int debuginfo__find_bpf_prologue(struct debuginfo *dbg,
+ struct perf_probe_event *pev,
+ char **result, int *count)
+{
+ struct probe_finder pf = {.pev = pev,
+ .callback = generate_bpf_prologue};
+ int ret;
+
+ pf.tvar = NULL;
+ ret = debuginfo__find_probes(dbg, &pf);
+ if (ret == -ERANGE)
+ ret = 0;
+
+ if (pf.tvar) {
+ *result = pf.tvar->insns;
+ *count = pf.tvar->insns_cnt;
+ free(pf.tvar);
+ } else {
+ *result = NULL;
+ *count = 0;
+ }
+
+ 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 ebf8c8c..28437978 100644
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -40,6 +40,10 @@ 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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