[PATCH v5 bpf-next 0/9] bpf: Add d_path helper - preparation changes

Jiri Olsa
2020-07-03T09:51:28Z

hi,
this patchset does preparation work for adding d_path helper,
which still needs more work, but the initial set of patches
is ready and useful to have.

This patchset adds:
- support to generate BTF ID lists that are resolved during
kernel linking and usable within kernel code with following
macros:

BTF_ID_LIST(bpf_skb_output_btf_ids)
BTF_ID(struct, sk_buff)

and access it in kernel code via:
extern u32 bpf_skb_output_btf_ids[];

- resolve_btfids tool that scans elf object for .BTF_ids
section and resolves its symbols with BTF ID values
- resolving of bpf_ctx_convert struct and several other
objects with BTF_ID_LIST

v5 changes:
- added acks to patches I did not change in this version
- split the original patchset into 2 parts and sending the first one
where the support to define BTF list is added, the BTF set support
will be posted later on [Andrii]
- used u32 instead of int in btf_ids.h [Andrii]
- changed the btf_ids.h define guard [Andrii]
- added resolve_btfids_clean target [Andrii]
- moved resolve_btfids test into prog_tests suite [Andrii]
- fixed BTF type iteration index in test [Andrii]
- removed btf_id checks in bpf_ctx_convert resolve code [Yonghong]
- removed WARN_ON_ONCE from btf_resolve_helper_id [Yonghong]
- added BTF_ID_UNUSED macro [Yonghong]
- fixed out of the tree build failure [0day bot]

Also available at:
https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
bpf/d_path

thanks,
jirka

---
Jiri Olsa (9):
bpf: Add resolve_btfids tool to resolve BTF IDs in ELF object
bpf: Compile resolve_btfids tool at kernel compilation start
bpf: Add BTF_ID_LIST/BTF_ID/BTF_ID_UNUSED macros
bpf: Resolve BTF IDs in vmlinux image
bpf: Remove btf_id helpers resolving
bpf: Use BTF_ID to resolve bpf_ctx_convert struct
bpf: Add info about .BTF.ids section to btf.rst
tools headers: Adopt verbatim copy of btf_ids.h from kernel sources
selftests/bpf: Add test for resolve_btfids

Documentation/bpf/btf.rst | 36 +++++
Makefile | 25 +++-
include/asm-generic/vmlinux.lds.h | 4 +
include/linux/btf_ids.h | 87 ++++++++++++
kernel/bpf/btf.c | 103 ++------------
kernel/trace/bpf_trace.c | 9 +-
net/core/filter.c | 9 +-
scripts/link-vmlinux.sh | 6 +
tools/Makefile | 3 +
tools/bpf/Makefile | 9 +-
tools/bpf/resolve_btfids/Build | 26 ++++
tools/bpf/resolve_btfids/Makefile | 77 +++++++++++
tools/bpf/resolve_btfids/main.c | 716 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
tools/include/linux/btf_ids.h | 87 ++++++++++++
tools/include/linux/compiler.h | 4 +
tools/testing/selftests/bpf/Makefile | 22 ++-
tools/testing/selftests/bpf/prog_tests/resolve_btfids.c | 170 +++++++++++++++++++++++
17 files changed, 1289 insertions(+), 104 deletions(-)
create mode 100644 include/linux/btf_ids.h
create mode 100644 tools/bpf/resolve_btfids/Build
create mode 100644 tools/bpf/resolve_btfids/Makefile
create mode 100644 tools/bpf/resolve_btfids/main.c
create mode 100644 tools/include/linux/btf_ids.h
create mode 100644 tools/testing/selftests/bpf/prog_tests/resolve_btfids.c