Re: Is GET_CR0_INTO_EAX macro unused?

From: Thomas Gleixner
Date: Tue Oct 03 2017 - 15:41:21 EST

On Mon, 2 Oct 2017, Denys Vlasenko wrote:

> Hi Andy,
> From by git archaeology, looks like last use of GET_CR0_INTO_EAX
> was removed long ago, in 2008 (see commit below).
> Right now, I only grep it here in a comment in entry_32.S:
> /*
> * We use macros for low-level operations which need to be overridden
> * for paravirtualization. The following will never clobber any registers:
> * INTERRUPT_RETURN (aka. "iret")
> * GET_CR0_INTO_EAX (aka. "movl %cr0, %eax")
> To support GET_CR0_INTO_EAX, paravirt has PV_CPU_read_cr0 a.k.a.
> struct pv_cpu_ops::read_cr0 and a bunch of code to support it
> for each hypervisor.
> Can we delete it?
> Or am I missing a non-obvious place where this macro is still in use?

That thing was simply forgotten and bitrots happily since 2008.