[RFC PATCH 18/22] perf bpf: load eBPF programs into kernel.

[Wang Nan <wangnan0@huawei.com>]

This patch use bpf system call to load all eBPF programs into kernel.
Their fds are stored into prog_fd field in 'struct bpf_perf_prog'.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
---
 tools/perf/util/bpf-loader.c | 58 ++++++++++++++++++++++++++++++++++++++++++++
 tools/perf/util/bpf-loader.h |  3 +++
 2 files changed, 61 insertions(+)

diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index fe623df..0395483 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -324,6 +324,8 @@ bpf_perf_prog_free(struct bpf_perf_prog *prog)
 		clear_perf_probe_event(prog->pev);
 		bzero(prog->pev, sizeof(*prog->pev));
 	}
+	if (prog->prog_fd >= 0)
+		close(prog->prog_fd);
 	free(prog);
 }
 
@@ -372,6 +374,7 @@ bpf_perf_prog_alloc(struct bpf_obj *obj __maybe_unused,
 	memcpy(prog->insns, data,
 		prog->insns_cnt * sizeof(struct bpf_insn));
 	prog->idx = idx;
+	prog->prog_fd = -1;
 	return prog;
 out:
 	bpf_perf_prog_free(prog);
@@ -841,6 +844,59 @@ bpf_obj_relocate(struct bpf_obj *obj)
 	return 0;
 }
 
+static __u64 ptr_to_u64(void *ptr)
+{
+	return (__u64) (unsigned long) ptr;
+}
+
+static int
+bpf_perf_prog_load(struct bpf_obj *obj, struct bpf_perf_prog *prog)
+{
+	int fd;
+	union bpf_attr attr;
+#define LOG_BUF_SIZE 65536
+	static char bpf_log_buf[LOG_BUF_SIZE];
+
+	bzero(&attr, sizeof(attr));
+
+	attr.prog_type = BPF_PROG_TYPE_KPROBE;
+	attr.insn_cnt = prog->insns_cnt;
+	attr.insns = ptr_to_u64((void *) prog->insns);
+	attr.license = ptr_to_u64((void *) obj->license);
+	attr.log_buf = ptr_to_u64(bpf_log_buf);
+	attr.log_size = LOG_BUF_SIZE;
+	attr.log_level = 1;
+	attr.kern_version = obj->kern_version;
+
+	bpf_log_buf[0] = 0;
+	fd = sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
+
+	if (fd < 0) {
+		pr_err("bpf: load: failed to load program %s:\n"
+				"-- BEGIN DUMP LOG ---\n%s\n-- END LOG --\n",
+				prog->name, bpf_log_buf);
+		return fd;
+	}
+	pr_debug("bpf load: load program %s as %d\n", prog->name, fd);
+	prog->prog_fd = fd;
+
+	return 0;
+}
+
+static int
+bpf_obj_load_progs(struct bpf_obj *obj)
+{
+	struct bpf_perf_prog *prog;
+	int err;
+
+	list_for_each_entry(prog, &obj->progs_list, list) {
+		err = bpf_perf_prog_load(obj, prog);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
 int bpf__load(const char *path)
 {
 	struct bpf_obj *obj;
@@ -873,6 +929,8 @@ int bpf__load(const char *path)
 		goto out;
 	if ((err = bpf_obj_relocate(obj)))
 		goto out;
+	if ((err = bpf_obj_load_progs(obj)))
+		goto out;
 
 	list_add(&obj->list, &bpf_obj_list);
 	return 0;
diff --git a/tools/perf/util/bpf-loader.h b/tools/perf/util/bpf-loader.h
index 756ac2e..dfdc3ca 100644
--- a/tools/perf/util/bpf-loader.h
+++ b/tools/perf/util/bpf-loader.h
@@ -29,6 +29,9 @@ struct bpf_perf_prog {
 	size_t insns_cnt;
 
 	struct perf_probe_event *pev;
+
+	/* fd of loaded eBPF program */
+	int prog_fd;
 };
 
 struct bpf_obj {
-- 
1.8.3.4