From: Ard Biesheuvel <ardb@xxxxxxxxxx> Weak external linkage is intended for cases where a symbol reference can remain unsatisfied in the final link. Taking the address of such a symbol should yield NULL if the reference was not satisfied. Given that ordinary RIP or PC relative references cannot produce NULL, some kind of indirection is always needed in such cases, and in position independent code, this results in a GOT entry. In ordinary code, it is arch specific but amounts to the same thing. While unavoidable in some cases, weak references are currently also used to declare symbols that are always defined in the final link, but not in the first linker pass. This means we end up with worse codegen for no good reason. So let's clean this up, by providing preliminary definitions that are only used as a fallback. Cc: Masahiro Yamada <masahiroy@xxxxxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Cc: Martin KaFai Lau <martin.lau@xxxxxxxxx> Cc: linux-arch@xxxxxxxxxxxxxxx Cc: linux-kbuild@xxxxxxxxxxxxxxx Cc: bpf@xxxxxxxxxxxxxxx Ard Biesheuvel (3): kallsyms: Avoid weak references for kallsyms symbols vmlinux: Avoid weak reference to notes section btf: Avoid weak external references include/asm-generic/vmlinux.lds.h | 21 ++++++++++++++ kernel/bpf/btf.c | 4 +-- kernel/kallsyms.c | 6 ---- kernel/kallsyms_internal.h | 30 ++++++++------------ kernel/ksysfs.c | 4 +-- lib/buildid.c | 4 +-- 6 files changed, 39 insertions(+), 30 deletions(-) -- 2.44.0.478.gd926399ef9-goog
