On 31/05/2024 10:34, Eduard Zingerman wrote: > On Tue, 2024-05-28 at 13:24 +0100, Alan Maguire wrote: >> Share relocation implementation with the kernel. As part of this, >> we also need the type/string visitation functions so add them to a >> btf_common.c file that also gets shared with the kernel. Relocation >> code in kernel and userspace is identical save for the impementation >> of the reparenting of split BTF to the relocated base BTF and >> retrieval of BTF header from "struct btf"; these small functions >> need separate user-space and kernel implementations. >> >> One other wrinkle on the kernel side is we have to map .BTF.ids in >> modules as they were generated with the type ids used at BTF encoding >> time. btf_relocate() optionally returns an array mapping from old BTF >> ids to relocated ids, so we use that to fix up these references where >> needed for kfuncs. >> >> Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx> >> --- > > I think we also need a test or a few tests to verify that ID sets are > converted correctly. > We sort of get that implicitly since bpf_testmod.ko will have a .BTF.base section, so its ID sets need to be relocated for the existing tests to work correctly. I'm thinking something that makes use of a bpf_iter_testmod_seq*() function while validating its BTF id > num base types might work, or did you have something specific in mind? Thanks! Alan > Acked-by: Eduard Zingerman <eddyz87@xxxxxxxxx>
