On Thu, Nov 11, 2021 at 5:26 PM Yonghong Song <yhs@xxxxxx> wrote: > > LLVM patches ([1] for clang, [2] and [3] for BPF backend) > added support for btf_type_tag attributes. This patch > added support for the kernel. > > The main motivation for btf_type_tag is to bring kernel > annotations __user, __rcu etc. to btf. With such information > available in btf, bpf verifier can detect mis-usages > and reject the program. For example, for __user tagged pointer, > developers can then use proper helper like bpf_probe_read_kernel() > etc. to read the data. > > BTF_KIND_TYPE_TAG may also useful for other tracing > facility where instead of to require user to specify > kernel/user address type, the kernel can detect it > by itself with btf. > > Patch 1 added support in kernel, Patch 2 for libbpf and Patch 3 > for bpftool. Patches 4-9 are for bpf selftests and Patch 10 > updated docs/bpf/btf.rst file with new btf kind. > > [1] https://reviews.llvm.org/D111199 > [2] https://reviews.llvm.org/D113222 > [3] https://reviews.llvm.org/D113496 > > Changelogs: > v2 -> v3: > - rebase to resolve merge conflicts. > v1 -> v2: > - add more dedup tests. > - remove build requirement for LLVM=1. > - remove testing macro __has_attribute in bpf programs > as it is always defined in recent clang compilers. Applied. Thanks. Cannot wait to get tags available in vmlinux.
