From: Thomas Gleixner <tglx@linutronix.de>
To: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>,
Andy Lutomirski <luto@amacapital.net>,
x86@kernel.org, LKML <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: Is GET_CR0_INTO_EAX macro unused?
Date: Tue, 3 Oct 2017 21:41:13 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.20.1710032139040.2278@nanos> (raw)
In-Reply-To: <9138e8d1-9e31-5ac7-a5cd-727967a847ef@redhat.com>
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.
Thanks,
tglx
prev parent reply other threads:[~2017-10-03 19:41 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-02 12:36 Denys Vlasenko
2017-10-03 19:41 ` Thomas Gleixner [this message]
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