[PATCH v1 bpf-next 0/9] BPF static branches

[Anton Protopopov <aspsk@isovalent.com>]

This series adds support for mapping between xlated and original
instructions offsets, mapping between xlated and jitted instructions
offsets (x86), support for two new BPF instruction JA[SRC=1]
(goto[l]_or_nop) and JA[SRC=3] (nop_or_goto[l]), and a new syscall to
configure the jitted values of such instructions.

This a follow up to the previous attempt to add static keys support
(see [1], [2]) which implements lower-level functionality than what
was proposed before.

The first patch .
The second patch adds xlated -> original mapping.
The third patch adds .

The fourth patch adds support for new instructions.
And the fifth patch adds support for new syscall.

The following patches are included:
  Patch 1 is a formal bug fix
  Patch 2 adds the xlated -> original mapping
  Patch 3 adds the xlated -> jitted mapping
  Patch 4 adds tests for instructions mappings
  Patch 5 adds bpftool support for printing new instructions
  Patch 6 add support for an extended JA instruction
  Patch 7 add support for kernel/bpftool to display new instructions
  Patch 8 adds a new BPF_STATIC_BRANCH_UPDATE syscall
  Patch 9 adds tests for the new ja* instructions and the new syscall

Altogether this provides enough functionality to dynamically patch
programs and support simple static keys.

rfc -> v1:
- converted to v1 based on the feedback (there was none)
- bpftool support was added to dump new instructions
- self-tests were added
- minor fixes & checkpatch warnings

  [1] https://lpc.events/event/17/contributions/1608/attachments/1278/2578/bpf-static-keys.pdf
  [2] https://lore.kernel.org/bpf/20231206141030.1478753-1-aspsk@isovalent.com/
  [3] https://github.com/llvm/llvm-project/pull/75110

Anton Protopopov (9):
  bpf: fix potential error return
  bpf: keep track of and expose xlated insn offsets
  bpf: expose how xlated insns map to jitted insns
  selftests/bpf: Add tests for instructions mappings
  bpftool: dump new fields of bpf prog info
  bpf: add support for an extended JA instruction
  bpf: Add kernel/bpftool asm support for new instructions
  bpf: add BPF_STATIC_BRANCH_UPDATE syscall
  selftests/bpf: Add tests for new ja* instructions

 arch/x86/net/bpf_jit_comp.c                   |  73 ++++-
 include/linux/bpf.h                           |  11 +
 include/linux/bpf_verifier.h                  |   1 -
 include/linux/filter.h                        |   1 +
 include/uapi/linux/bpf.h                      |  26 ++
 kernel/bpf/core.c                             |  67 ++++-
 kernel/bpf/disasm.c                           |  33 ++-
 kernel/bpf/syscall.c                          | 115 ++++++++
 kernel/bpf/verifier.c                         |  58 +++-
 tools/bpf/bpftool/prog.c                      |  14 +
 tools/bpf/bpftool/xlated_dumper.c             |  18 ++
 tools/bpf/bpftool/xlated_dumper.h             |   2 +
 tools/include/uapi/linux/bpf.h                |  26 ++
 .../bpf/prog_tests/bpf_insns_mappings.c       | 156 ++++++++++
 .../bpf/prog_tests/bpf_static_branches.c      | 269 ++++++++++++++++++
 .../selftests/bpf/progs/bpf_insns_mappings.c  | 155 ++++++++++
 16 files changed, 1002 insertions(+), 23 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/bpf_insns_mappings.c
 create mode 100644 tools/testing/selftests/bpf/prog_tests/bpf_static_branches.c
 create mode 100644 tools/testing/selftests/bpf/progs/bpf_insns_mappings.c

-- 
2.34.1