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] and JA[SRC=3], 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. It's RFC because 1) to run self-tests it requires a patched llvm (https://github.com/llvm/llvm-project/pull/75110, thanks a lot Yonghong!) 2) before spending time writing selftests and proper bpftool updates [this time] I would prefer to get some initial feedback first (for examples, see below) The first patch is a formal fix. The second patch adds xlated -> original mapping. The third patch adds xlated -> jitted mapping. The fourth patch adds support for new instructions. And the fifth patch adds support for new syscall. Altogether this provides enough functionality to dynamically patch programs and support simple static keys. See the third patch which displays an example of mappings between xlated->orig, xlated->jited. See the last patch which includes description of how to implement simple static key functionality. This would be also interesting to hear what people think about more high-level api where one "key" controls a set of static branches in multiple programs and can serialize access to all the branches. What kind of BPF object can represent such functionality, besides a map, if any? [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@xxxxxxxxxxxxx/ Anton Protopopov (5): bpf: fix potential error return bpf: keep track of and expose xlated insn offsets bpf: x86: expose how xlated insns map to jitted insns bpf: add support for an extended JA instruction bpf: x86: add BPF_STATIC_BRANCH_UPDATE syscall arch/x86/net/bpf_jit_comp.c | 71 ++++++++++++++++++- 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 | 69 +++++++++++++++++- kernel/bpf/syscall.c | 112 ++++++++++++++++++++++++++++++ kernel/bpf/verifier.c | 58 ++++++++++++---- tools/bpf/bpftool/prog.c | 14 ++++ tools/bpf/bpftool/xlated_dumper.c | 2 +- tools/bpf/bpftool/xlated_dumper.h | 2 + tools/include/uapi/linux/bpf.h | 26 +++++++ 12 files changed, 375 insertions(+), 18 deletions(-) -- 2.34.1
