[PATCH 1/5] powerpc/64s: Kernel Hypervisor Restricted Access Prevention

[Michael Ellerman]

Russell Currey <ruscur at russell.cc> writes:
> diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
> index 7b1693adff2a..090f72cbb02d 100644
> --- a/arch/powerpc/kernel/entry_64.S
> +++ b/arch/powerpc/kernel/entry_64.S
> @@ -286,6 +286,9 @@ BEGIN_FTR_SECTION
>  	HMT_MEDIUM_LOW
>  END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
>  
> +	/* headed back to userspace, so unlock the AMR */
> +	UNLOCK_AMR(r2)
> +

This one needs an ifdef, or preferable an empty version in a header for
non-book3s 64, otherwise we get:

  arch/powerpc/kernel/entry_64.S: Assembler messages:
  arch/powerpc/kernel/entry_64.S:290: Error: unrecognized opcode: `unlock_amr(%r2)'
  scripts/Makefile.build:405: recipe for target 'arch/powerpc/kernel/entry_64.o' failed

That's a corenet64-ish defconfig.

cheers