bpf: Allow names of Rust types and functions in BTF

Names of types and functions in BTF that LLVM makes for a Rust program
are not C identifiers:

  [69] STRUCT 'NonNull<str>' size=16 vlen=1
  [147] FUNC 'write_fmt<scx_cosmos::BpfStream>' type_id=146

and the kernel rejects such BTF with "Invalid name". scx_simple and
scx_cosmos schedulers written in Rust have them in STRUCT, FWD and FUNC,
made of letters, digits and " #&()*,:;<>[]{}", 430 characters at most.

Allow any printable character in btf_name_valid_identifier(), like it's
done for DATASEC. It checks names of types, functions, members,
enumerators, variables and arguments, so all of them can have such
characters now. The limit of KSYM_NAME_LEN stays.

The name of FUNC is a part of the name of the program in kallsyms, where
a space would break the parsers. Replace what is not a character of
an identifier with '_' there.

Tests in prog_tests/btf.c expect "Invalid name" for names with '!' and
'*', which are valid now. Put a character that is not printable there.
The type name '?foo' is expected to load.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20261002124714.180012-6-alexei.starovoitov@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

0 files changed, 0 insertions, 0 deletions