From: Yonghong Song Date: Thu, 12 Jun 2025 04:30:49 +0000 (-0700) Subject: docs/bpf: Default cpu version changed from v1 to v3 in llvm 20 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=50034d93628143c747e90418b5bf7df6851ac612;p=thirdparty%2Fkernel%2Flinux.git docs/bpf: Default cpu version changed from v1 to v3 in llvm 20 The default cpu version is changed from v1 to v3 in llvm version 20. See [1] for more detailed reasoning. Update bpf_devel_QA.rst so developers can find such information easily. [1] https://github.com/llvm/llvm-project/pull/107008 Signed-off-by: Yonghong Song Link: https://lore.kernel.org/r/20250612043049.2411989-1-yonghong.song@linux.dev Signed-off-by: Alexei Starovoitov --- diff --git a/Documentation/bpf/bpf_devel_QA.rst b/Documentation/bpf/bpf_devel_QA.rst index 0acb4c9b8d90f..45bc5c5cd7937 100644 --- a/Documentation/bpf/bpf_devel_QA.rst +++ b/Documentation/bpf/bpf_devel_QA.rst @@ -611,9 +611,10 @@ Q: I have added a new BPF instruction to the kernel, how can I integrate it into LLVM? A: LLVM has a ``-mcpu`` selector for the BPF back end in order to allow -the selection of BPF instruction set extensions. By default the -``generic`` processor target is used, which is the base instruction set -(v1) of BPF. +the selection of BPF instruction set extensions. Before llvm version 20, +the ``generic`` processor target is used, which is the base instruction +set (v1) of BPF. Since llvm 20, the default processor target has changed +to instruction set v3. LLVM has an option to select ``-mcpu=probe`` where it will probe the host kernel for supported BPF instruction set extensions and selects the