[tip:perf/core] tools lib bpf: New API to adjust type of a BPF program

[tip-bot for Wang Nan]

Commit-ID:  5f44e4c810bf3ace5a97a84554d4eeccbb563ca5
Gitweb:     http://git.kernel.org/tip/5f44e4c810bf3ace5a97a84554d4eeccbb563ca5
Author:     Wang Nan <wangnan0@xxxxxxxxxx>
AuthorDate: Wed, 13 Jul 2016 10:44:01 +0000
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Wed, 13 Jul 2016 23:09:02 -0300

tools lib bpf: New API to adjust type of a BPF program

Add 4 new APIs to adjust and query the type of a BPF program.
Load program according to type set by caller. Default is set to
BPF_PROG_TYPE_KPROBE.

Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Cc: pi3orama@xxxxxxx
Link: http://lkml.kernel.org/r/1468406646-21642-2-git-send-email-wangnan0@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/lib/bpf/libbpf.c | 53 +++++++++++++++++++++++++++++++++++++++++++-------
 tools/lib/bpf/libbpf.h |  9 +++++++++
 2 files changed, 55 insertions(+), 7 deletions(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 3dcda9e..4751936 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -158,6 +158,7 @@ struct bpf_program {
 	char *section_name;
 	struct bpf_insn *insns;
 	size_t insns_cnt;
+	enum bpf_prog_type type;
 
 	struct {
 		int insn_idx;
@@ -299,6 +300,7 @@ bpf_program__init(void *data, size_t size, char *name, int idx,
 	prog->idx = idx;
 	prog->instances.fds = NULL;
 	prog->instances.nr = -1;
+	prog->type = BPF_PROG_TYPE_KPROBE;
 
 	return 0;
 errout:
@@ -894,8 +896,8 @@ static int bpf_object__collect_reloc(struct bpf_object *obj)
 }
 
 static int
-load_program(struct bpf_insn *insns, int insns_cnt,
-	     char *license, u32 kern_version, int *pfd)
+load_program(enum bpf_prog_type type, struct bpf_insn *insns,
+	     int insns_cnt, char *license, u32 kern_version, int *pfd)
 {
 	int ret;
 	char *log_buf;
@@ -907,9 +909,8 @@ load_program(struct bpf_insn *insns, int insns_cnt,
 	if (!log_buf)
 		pr_warning("Alloc log buffer for bpf loader error, continue without log\n");
 
-	ret = bpf_load_program(BPF_PROG_TYPE_KPROBE, insns,
-			       insns_cnt, license, kern_version,
-			       log_buf, BPF_LOG_BUF_SIZE);
+	ret = bpf_load_program(type, insns, insns_cnt, license,
+			       kern_version, log_buf, BPF_LOG_BUF_SIZE);
 
 	if (ret >= 0) {
 		*pfd = ret;
@@ -968,7 +969,7 @@ bpf_program__load(struct bpf_program *prog,
 			pr_warning("Program '%s' is inconsistent: nr(%d) != 1\n",
 				   prog->section_name, prog->instances.nr);
 		}
-		err = load_program(prog->insns, prog->insns_cnt,
+		err = load_program(prog->type, prog->insns, prog->insns_cnt,
 				   license, kern_version, &fd);
 		if (!err)
 			prog->instances.fds[0] = fd;
@@ -997,7 +998,7 @@ bpf_program__load(struct bpf_program *prog,
 			continue;
 		}
 
-		err = load_program(result.new_insn_ptr,
+		err = load_program(prog->type, result.new_insn_ptr,
 				   result.new_insn_cnt,
 				   license, kern_version, &fd);
 
@@ -1316,6 +1317,44 @@ int bpf_program__nth_fd(struct bpf_program *prog, int n)
 	return fd;
 }
 
+static void bpf_program__set_type(struct bpf_program *prog,
+				  enum bpf_prog_type type)
+{
+	prog->type = type;
+}
+
+int bpf_program__set_tracepoint(struct bpf_program *prog)
+{
+	if (!prog)
+		return -EINVAL;
+	bpf_program__set_type(prog, BPF_PROG_TYPE_TRACEPOINT);
+	return 0;
+}
+
+int bpf_program__set_kprobe(struct bpf_program *prog)
+{
+	if (!prog)
+		return -EINVAL;
+	bpf_program__set_type(prog, BPF_PROG_TYPE_KPROBE);
+	return 0;
+}
+
+static bool bpf_program__is_type(struct bpf_program *prog,
+				 enum bpf_prog_type type)
+{
+	return prog ? (prog->type == type) : false;
+}
+
+bool bpf_program__is_tracepoint(struct bpf_program *prog)
+{
+	return bpf_program__is_type(prog, BPF_PROG_TYPE_TRACEPOINT);
+}
+
+bool bpf_program__is_kprobe(struct bpf_program *prog)
+{
+	return bpf_program__is_type(prog, BPF_PROG_TYPE_KPROBE);
+}
+
 int bpf_map__fd(struct bpf_map *map)
 {
 	return map ? map->fd : -EINVAL;
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index f392c5e..eb2a4c4 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -165,6 +165,15 @@ int bpf_program__set_prep(struct bpf_program *prog, int nr_instance,
 int bpf_program__nth_fd(struct bpf_program *prog, int n);
 
 /*
+ * Adjust type of bpf program. Default is kprobe.
+ */
+int bpf_program__set_tracepoint(struct bpf_program *prog);
+int bpf_program__set_kprobe(struct bpf_program *prog);
+
+bool bpf_program__is_tracepoint(struct bpf_program *prog);
+bool bpf_program__is_kprobe(struct bpf_program *prog);
+
+/*
  * We don't need __attribute__((packed)) now since it is
  * unnecessary for 'bpf_map_def' because they are all aligned.
  * In addition, using it will trigger -Wpacked warning message,