On Wed, Jun 24, 2020 at 01:31:38PM -0700, Sami Tolvanen wrote: > This patch series adds support for building x86_64 and arm64 kernels > with Clang's Link Time Optimization (LTO). > > In addition to performance, the primary motivation for LTO is to allow > Clang's Control-Flow Integrity (CFI) to be used in the kernel. Google's > Pixel devices have shipped with LTO+CFI kernels since 2018. > > Most of the patches are build system changes for handling LLVM bitcode, > which Clang produces with LTO instead of ELF object files, postponing > ELF processing until a later stage, and ensuring initcall ordering. > > Note that first objtool patch in the series is already in linux-next, > but as it's needed with LTO, I'm including it also here to make testing > easier. I'm very sad that yet again, memory ordering isn't addressed. LTO vastly increases the range of the optimizer to wreck things.
