enable LTO for riscv

[nickdesaulniers]

I don't see it pushed to the riscv tree yet, but LTO for riscv is coming.

[nickdesaulniers]

wonder if this has landed yet?
https://lore.kernel.org/llvm/20220512205545.992288-1-twd2.me@gmail.com/

[nathanchance]

I don't see it on any branch in https://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux.git/ nor in mainline.

[nickdesaulniers]

cc @twd2

[twd2]

I saw my patch was once applied to for-next but later that commit was removed from the tree.
Is there anything I can improve? @palmer-dabbelt

[nathanchance]

@twd2 I sent a ping for it recently but I think it might just be better to resend the patch at this point. The RISC-V folks recently went back to tracking patches via Patchwork, which should help ensure the patch does not get lost (as well as make it obvious to you when it has been picked up).

[nathanchance]

I sent v3 due to arch/riscv/kernel/pi needing LTO disabled: https://lore.kernel.org/20231003-riscv-lto-v3-1-8aca61a4ecb4@kernel.org/

[twd2]

Cool! Thanks!

[nathanchance]

This has been accepted and is now available in -next, so we should be able to get this wired up there:

https://git.kernel.org/next/linux-next/c/021d23428bdbae032294e8f4a29cb53cb50ae71c