linux-kernel - Re: [PATCH v2 08/12] x86/paravirt: remove no longer needed 32-bit pvops cruft

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Message-ID: <20201120165231.GA1074066@rani.riverdale.lan>
Date:   Fri, 20 Nov 2020 11:52:31 -0500
From:   Arvind Sankar <nivedita@...m.mit.edu>
To:     Juergen Gross <jgross@...e.com>
Cc:     xen-devel@...ts.xenproject.org, x86@...nel.org,
        linux-kernel@...r.kernel.org,
        virtualization@...ts.linux-foundation.org, peterz@...radead.org,
        luto@...nel.org, Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>, Deep Shah <sdeep@...are.com>,
        "VMware, Inc." <pv-drivers@...are.com>
Subject: Re: [PATCH v2 08/12] x86/paravirt: remove no longer needed 32-bit
 pvops cruft

On Fri, Nov 20, 2020 at 12:46:26PM +0100, Juergen Gross wrote:
> PVOP_VCALL4() is only used for Xen PV, while PVOP_CALL4() isn't used
> at all. Keep PVOP_CALL4() for 64 bits due to symmetry reasons.
> 
> This allows to remove the 32-bit definitions of those macros leading
> to a substantial simplification of the paravirt macros, as those were
> the only ones needing non-empty "pre" and "post" parameters.
> 
> PVOP_CALLEE2() and PVOP_VCALLEE2() are used nowhere, so remove them.
> 
> Another no longer needed case is special handling of return types
> larger than unsigned long. Replace that with a BUILD_BUG_ON().
> 
> DISABLE_INTERRUPTS() is used in 32-bit code only, so it can just be
> replaced by cli.
> 
> INTERRUPT_RETURN in 32-bit code can be replaced by iret.
> 
> GET_CR2_INTO_AX and ENABLE_INTERRUPTS are used nowhere, so they can
> be removed.

As a heads-up, GET_CR2_INTO_AX has been removed in tip:master already by
  31d854603305 ("x86/head/64: Remove unused GET_CR2_INTO() macro")