Re: [PATCH v9 0/6] add support for relative references in special sections

Ard Biesheuvel [off-list ref] writes:

This adds support for emitting special sections such as initcall arrays,
PCI fixups and tracepoints as relative references rather than absolute
references. This reduces the size by 50% on 64-bit architectures, but
more importantly, it removes the need for carrying relocation metadata
for these sections in relocatable kernels (e.g., for KASLR) that needs
to be fixed up at boot time. On arm64, this reduces the vmlinux footprint
of such a reference by 8x (8 byte absolute reference + 24 byte RELA entry
vs 4 byte relative reference)

...

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Kees Cook <redacted>
Cc: Will Deacon <redacted>
Cc: Michael Ellerman <mpe@ellerman.id.au>

This seems to be working on powerpc.

It boots on a couple of machines with no obvious badness.

And there's some size reduction with a random config I had lying around:

  Total: Before=14820494, After=14673313, chg -0.99%


It can get some more testing once it's in linux-next as far as I'm
concerned.

  Acked-by: Michael Ellerman [off-list ref] (powerpc)

cheers