On Sun, Feb 4, 2024 at 1:06 PM Daniel Xu <dxu@xxxxxxxxx> wrote: > > This patchset enables dumping kfunc prototypes from bpftool. This is > useful b/c with this patchset, end users will no longer have to manually > define kfunc prototypes. For the kernel tree, this also means we can > drop kfunc prototypes from: > > tools/testing/selftests/bpf/bpf_kfuncs.h > tools/testing/selftests/bpf/bpf_experimental.h > > Example usage: > > $ make PAHOLE=/home/dxu/dev/pahole/build/pahole -j30 vmlinux > > $ ./tools/bpf/bpftool/bpftool btf dump file ./vmlinux format c | rg "__ksym;" | head -3 > extern void cgroup_rstat_updated(struct cgroup *cgrp, int cpu) __weak __ksym; > extern void cgroup_rstat_flush(struct cgroup *cgrp) __weak __ksym; > extern struct bpf_key *bpf_lookup_user_key(u32 serial, u64 flags) __weak __ksym; > > Note that this patchset is only effective after the enabling pahole [0] > change is merged and the resulting feature enabled with > --btf_features=decl_tag_kfuncs. > > [0]: https://lore.kernel.org/bpf/cover.1707071969.git.dxu@xxxxxxxxx/ > > === Changelog === > > From v1: > * Add __weak annotation > * Use btf_dump for kfunc prototypes > * Update kernel bpf_rdonly_cast() signature > > Daniel Xu (2): > bpf: Have bpf_rdonly_cast() take a const pointer > bpftool: Support dumping kfunc prototypes from BTF I've applied patch #1 as it's a good change regardless. Please send v2 for patch #2. > > kernel/bpf/helpers.c | 4 ++-- > tools/bpf/bpftool/btf.c | 45 +++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 47 insertions(+), 2 deletions(-) > > -- > 2.42.1 >
