Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Daniel Borkmann says:

====================
pull-request: bpf-next 2020-02-21

The following pull-request contains BPF updates for your *net-next* tree.

We've added 25 non-merge commits during the last 4 day(s) which contain
a total of 33 files changed, 2433 insertions(+), 161 deletions(-).

The main changes are:

1) Allow for adding TCP listen sockets into sock_map/hash so they can be used
   with reuseport BPF programs, from Jakub Sitnicki.

2) Add a new bpf_program__set_attach_target() helper for adding libbpf support
   to specify the tracepoint/function dynamically, from Eelco Chaudron.

3) Add bpf_read_branch_records() BPF helper which helps use cases like profile
   guided optimizations, from Daniel Xu.

4) Enable bpf_perf_event_read_value() in all tracing programs, from Song Liu.

5) Relax BTF mandatory check if only used for libbpf itself e.g. to process
   BTF defined maps, from Andrii Nakryiko.

6) Move BPF selftests -mcpu compilation attribute from 'probe' to 'v3' as it has
   been observed that former fails in envs with low memlock, from Yonghong Song.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 31 insertions, 7 deletions

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 7469c7dcc15e..996162801f7a 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -2286,9 +2286,7 @@ static void bpf_object__sanitize_btf_ext(struct bpf_object *obj)
 
 static bool bpf_object__is_btf_mandatory(const struct bpf_object *obj)
 {
-	return obj->efile.btf_maps_shndx >= 0 ||
-		obj->efile.st_ops_shndx >= 0 ||
-		obj->nr_extern > 0;
+	return obj->efile.st_ops_shndx >= 0 || obj->nr_extern > 0;
 }
 
 static int bpf_object__init_btf(struct bpf_object *obj,
@@ -4945,8 +4943,8 @@ int bpf_program__load(struct bpf_program *prog, char *license, __u32 kern_ver)
 {
 	int err = 0, fd, i, btf_id;
 
-	if (prog->type == BPF_PROG_TYPE_TRACING ||
-	    prog->type == BPF_PROG_TYPE_EXT) {
+	if ((prog->type == BPF_PROG_TYPE_TRACING ||
+	     prog->type == BPF_PROG_TYPE_EXT) && !prog->attach_btf_id) {
 		btf_id = libbpf_find_attach_btf_id(prog);
 		if (btf_id <= 0)
 			return btf_id;
@@ -6589,6 +6587,9 @@ static inline int __find_vmlinux_btf_id(struct btf *btf, const char *name,
 	else
 		err = btf__find_by_name_kind(btf, name, BTF_KIND_FUNC);
 
+	if (err <= 0)
+		pr_warn("%s is not found in vmlinux BTF\n", name);
+
 	return err;
 }
 
@@ -6661,8 +6662,6 @@ static int libbpf_find_attach_btf_id(struct bpf_program *prog)
 			err = __find_vmlinux_btf_id(prog->obj->btf_vmlinux,
 						    name + section_defs[i].len,
 						    attach_type);
-		if (err <= 0)
-			pr_warn("%s is not found in vmlinux BTF\n", name);
 		return err;
 	}
 	pr_warn("failed to identify btf_id based on ELF section name '%s'\n", name);
@@ -8138,6 +8137,31 @@ void bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear)
 	}
 }
 
+int bpf_program__set_attach_target(struct bpf_program *prog,
+				   int attach_prog_fd,
+				   const char *attach_func_name)
+{
+	int btf_id;
+
+	if (!prog || attach_prog_fd < 0 || !attach_func_name)
+		return -EINVAL;
+
+	if (attach_prog_fd)
+		btf_id = libbpf_find_prog_btf_id(attach_func_name,
+						 attach_prog_fd);
+	else
+		btf_id = __find_vmlinux_btf_id(prog->obj->btf_vmlinux,
+					       attach_func_name,
+					       prog->expected_attach_type);
+
+	if (btf_id < 0)
+		return btf_id;
+
+	prog->attach_btf_id = btf_id;
+	prog->attach_prog_fd = attach_prog_fd;
+	return 0;
+}
+
 int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz)
 {
 	int err = 0, n, len, start, end = -1;