[PATCH] D110869: [X86] Implement -fzero-call-used-regs option

Thu Feb 3 12:23:01 PST 2022

nathanchance added a comment.

This diff allows me to boot on bare metal as of v5.17-rc2:

  diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
  index 6aef9ee28a39..8ee176dac669 100644
  --- a/arch/x86/kernel/Makefile
  +++ b/arch/x86/kernel/Makefile
  @@ -125,6 +125,7 @@ obj-$(CONFIG_DEBUG_NMI_SELFTEST) += nmi_selftest.o

   obj-$(CONFIG_KVM_GUEST)                += kvm.o kvmclock.o
   obj-$(CONFIG_PARAVIRT)         += paravirt.o
  +CFLAGS_paravirt.o += -fzero-call-used-regs=skip
   obj-$(CONFIG_PARAVIRT_SPINLOCKS)+= paravirt-spinlocks.o
   obj-$(CONFIG_PARAVIRT_CLOCK)   += pvclock.o
   obj-$(CONFIG_X86_PMEM_LEGACY_DEVICE) += pmem.o

I have uploaded the config used, the preprocessed file, and the "good" object (with the following diff) and the "bad" object (without the above diff) here: https://github.com/nathanchance/bug-files/tree/052a31e6d94c1b349cf6f3128087944444dace24/D110869

If there is any more information I can give, please let me know!

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D110869/new/

https://reviews.llvm.org/D110869