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Subject[RFC PATCH 6/6] perf bpf: Generate bpf prologue for arguments
Date
Generate bpf prologue before attaching bpf progs to perf probe event. If
prologue is generated, it will be pasted in front of the original bpf
prog.

Signed-off-by: He Kuang <hekuang@huawei.com>
---
tools/perf/util/bpf-loader.c | 66 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 66 insertions(+)

diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index c646ca4..8c746ef 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -900,6 +900,69 @@ bpf_perf_prog_load(struct bpf_obj *obj, struct bpf_perf_prog *prog)
return 0;
}

+#ifdef HAVE_DWARF_SUPPORT
+#if 0
+static void show_bpf_insn(char *buf, int len)
+{
+ int i, j;
+ char *ptr = buf;
+
+ for (i = 0; i < len; i++) {
+ pr_debug("[%03d] ", i);
+ for (j = 0; j < 8; j++)
+ pr_debug("0x%02x, ", (*ptr++) & 0xff);
+ pr_debug("\\\n");
+ }
+}
+#endif
+
+static int bpf_obj_prologue(struct bpf_obj *obj)
+{
+ struct bpf_perf_prog *prog;
+ int ret = -1;
+
+ list_for_each_entry(prog, &obj->progs_list, list) {
+ int count;
+ char *result;
+ int new_count;
+
+ if (!prog->pev)
+ continue;
+
+ ret = get_bpf_prologue(prog->pev, &result, &count);
+ if (ret)
+ return ret;
+
+ if (count > 0) {
+ bpf_dump_prog((struct bpf_insn *)result, count);
+
+ new_count = prog->insns_cnt + count;
+ result = realloc(result,
+ new_count * sizeof(struct bpf_insn));
+ if (!result)
+ return -ENOMEM;
+
+ memcpy(result + count * sizeof(struct bpf_insn),
+ prog->insns,
+ prog->insns_cnt * sizeof(struct bpf_insn));
+
+ free(prog->insns);
+ prog->insns = (struct bpf_insn *)result;
+ prog->insns_cnt = new_count;
+ } else {
+ pr_debug("bpf: no prologue generated\n");
+ }
+ }
+
+ return ret;
+}
+#else
+static int bpf_progs_prologue(struct bpf_obj *obj __maybe_unused)
+{
+ return 0;
+}
+#endif
+
static int
bpf_obj_load_progs(struct bpf_obj *obj)
{
@@ -946,6 +1009,9 @@ int bpf__load(const char *path)
goto out;
if ((err = bpf_obj_relocate(obj)))
goto out;
+ err = bpf_obj_prologue(obj);
+ if (err)
+ goto out;
if ((err = bpf_obj_load_progs(obj)))
goto out;

--
1.8.5.2


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