After gethered all vars represented in trace_probe_arg, we can now use
functions in libbpf to generate the args prologue.
Signed-off-by: He Kuang <heku...@huawei.com>
---
tools/perf/util/probe-finder.c | 83 +++++++++++++++++++++++++++++++++++++++++-
1 file changed, 81 insertions(+), 2 deletions(-)
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 6785eab..455ff0f 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -1242,6 +1242,67 @@ end:
return ret;
}
+/*
+ * Convert args to bpf prologue
+ * 1) First pass for calculating the new program length:
+ * synthesize_probe_bpf(arg, nargs, NULL, &new_len);
+ *
+ * 2) 2nd pass do the actually convert
+ * new_prog = malloc(sizeof(struct bpf_insn) * new_len);
+ * synthesize_probe_bpf(arg, nargs, new_prog, &new_len);
+ */
+static int synthesize_probe_bpf(struct probe_trace_arg *arg,
+ int nargs,
+ char *new_prog,
+ int *new_len)
+{
+ int i;
+ char *new_insn = new_prog;
+
+ if (nargs == 0) {
+ *new_len = 0;
+ return 0;
+ }
+
+ new_insn += bpf_prologue_begin(new_prog);
+ /* Find each argument */
+ for (i = 0; i < nargs; i++) {
+ struct probe_trace_arg_ref *ref = arg[i].ref;
+ unsigned int regn = arg[i].regn;
+
+ /* Print argument value */
+ if (arg[i].value[0] == '@' && ref) {
+ /* TODO parse other arguments */
+ pr_debug("%d%+ld", regn, ref->offset);
+ } else {
+ int depth = 0;
+
+ new_insn += bpf_prologue_arg_deref(
+ get_arch_reg_offset(regn),
+ i + 1,
+ depth++,
+ new_prog ? new_insn : NULL,
+ !ref);
+
+ while (ref) {
+ new_insn += bpf_prologue_arg_deref(
+ ref->offset,
+ i + 1,
+ depth++,
+ new_prog ? new_insn : NULL,
+ !ref->next);
+ ref = ref->next;
+ }
+ }
+ }
+
+ new_insn += bpf_prologue_end(new_prog ? new_insn : NULL,
+ nargs);
+ *new_len = new_insn - new_prog;
+
+ return 0;
+}
+
/* Add a found probe point into trace event list */
static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
{
@@ -1335,6 +1396,8 @@ int debuginfo__find_bpf_prologue(struct debuginfo *dbg,
.pf = {.pev = pev, .callback = generate_bpf_prologue},
.mod = dbg->mod, .max_tevs = BPF_MAX_TEVS};
struct probe_trace_event *tevs;
+ struct probe_trace_event *tev;
+ char *new_prog;
int ret;
/* Allocate result tevs array */
@@ -1347,9 +1410,25 @@ int debuginfo__find_bpf_prologue(struct debuginfo *dbg,
ret = debuginfo__find_probes(dbg, &tf.pf);
- *result = NULL;
- *count = 0;
+ tev = &tevs[0];
+
+ synthesize_probe_bpf(tev->args, tev->nargs, NULL, count);
+ if (*count == 0)
+ goto end;
+
+ new_prog = malloc(*count);
+ if (!new_prog) {
+ ret = -ENOMEM;
+ goto end;
+ }
+ synthesize_probe_bpf(tev->args, tev->nargs, new_prog, count);
+
+ /* assign result to tvar */
+ *result = (char *)new_prog;
+
+end:
+ /* release tevs */
free(tevs);
return ret;
}
--
1.8.5.2
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