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authorAndrii Nakryiko <andrii@kernel.org>2021-08-15 00:05:57 -0700
committerDaniel Borkmann <daniel@iogearbox.net>2021-08-17 00:45:07 +0200
commitb89fbfbb854c9afc3047e8273cc3a694650b802e (patch)
treec7b3624e206ecc2f865cefb688bcdbf173c1beaa /include/linux/bpf_types.h
parent652c1b17b85b9c195978c051aa283027529db1fe (diff)
bpf: Implement minimal BPF perf link
Introduce a new type of BPF link - BPF perf link. This brings perf_event-based BPF program attachments (perf_event, tracepoints, kprobes, and uprobes) into the common BPF link infrastructure, allowing to list all active perf_event based attachments, auto-detaching BPF program from perf_event when link's FD is closed, get generic BPF link fdinfo/get_info functionality. BPF_LINK_CREATE command expects perf_event's FD as target_fd. No extra flags are currently supported. Force-detaching and atomic BPF program updates are not yet implemented, but with perf_event-based BPF links we now have common framework for this without the need to extend ioctl()-based perf_event interface. One interesting consideration is a new value for bpf_attach_type, which BPF_LINK_CREATE command expects. Generally, it's either 1-to-1 mapping from bpf_attach_type to bpf_prog_type, or many-to-1 mapping from a subset of bpf_attach_types to one bpf_prog_type (e.g., see BPF_PROG_TYPE_SK_SKB or BPF_PROG_TYPE_CGROUP_SOCK). In this case, though, we have three different program types (KPROBE, TRACEPOINT, PERF_EVENT) using the same perf_event-based mechanism, so it's many bpf_prog_types to one bpf_attach_type. I chose to define a single BPF_PERF_EVENT attach type for all of them and adjust link_create()'s logic for checking correspondence between attach type and program type. The alternative would be to define three new attach types (e.g., BPF_KPROBE, BPF_TRACEPOINT, and BPF_PERF_EVENT), but that seemed like unnecessary overkill and BPF_KPROBE will cause naming conflicts with BPF_KPROBE() macro, defined by libbpf. I chose to not do this to avoid unnecessary proliferation of bpf_attach_type enum values and not have to deal with naming conflicts. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/bpf/20210815070609.987780-5-andrii@kernel.org
Diffstat (limited to 'include/linux/bpf_types.h')
-rw-r--r--include/linux/bpf_types.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h
index ae3ac3a2018c..9c81724e4b98 100644
--- a/include/linux/bpf_types.h
+++ b/include/linux/bpf_types.h
@@ -136,3 +136,6 @@ BPF_LINK_TYPE(BPF_LINK_TYPE_ITER, iter)
BPF_LINK_TYPE(BPF_LINK_TYPE_NETNS, netns)
BPF_LINK_TYPE(BPF_LINK_TYPE_XDP, xdp)
#endif
+#ifdef CONFIG_PERF_EVENTS
+BPF_LINK_TYPE(BPF_LINK_TYPE_PERF_EVENT, perf)
+#endif