linux-kernel - Re: [PATCH v9 15/18] arm64: kexec: kexec EL2 vectors

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Date:   Mon, 25 Jan 2021 14:07:39 -0500
From:   Pavel Tatashin <pasha.tatashin@...een.com>
To:     Marc Zyngier <maz@...nel.org>
Cc:     James Morris <jmorris@...ei.org>, Sasha Levin <sashal@...nel.org>,
        "Eric W. Biederman" <ebiederm@...ssion.com>,
        kexec mailing list <kexec@...ts.infradead.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Jonathan Corbet <corbet@....net>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        James Morse <james.morse@....com>,
        Vladimir Murzin <vladimir.murzin@....com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Bhupesh Sharma <bhsharma@...hat.com>,
        linux-mm <linux-mm@...ck.org>,
        Mark Rutland <mark.rutland@....com>, steve.capper@....com,
        rfontana@...hat.com, Thomas Gleixner <tglx@...utronix.de>,
        Selin Dag <selindag@...il.com>
Subject: Re: [PATCH v9 15/18] arm64: kexec: kexec EL2 vectors

> > +.macro el1_sync_64
> > +     br      x4                      /* Jump to new world from el2 */
> > +     .fill 31, 4, 0                  /* Set other 31 instr to zeroes */
> > +.endm
>
> The common idiom to write this is to align the beginning of the
> macro, and not to bother about what follows:
>
> .macro whatever
>          .align 7
>          br      x4
> .endm
>
> Specially given that 0 is an undefined instruction, and I really hate to
> see
> those in the actual text. On the contrary, .align generates NOPs.

Fixed that.

>
> > +
> > +.macro invalid_vector label
> > +\label:
> > +     b \label
> > +     .fill 31, 4, 0                  /* Set other 31 instr to zeroes */
> > +.endm
> > +
> > +/* el2 vectors - switch el2 here while we restore the memory image. */
> > +     .align 11
> > +ENTRY(kexec_el2_vectors)
>
> Please see commit 617a2f392c92 ("arm64: kvm: Annotate assembly using
> modern
> annoations"), and follow the same pattern.

Fixed that as well.

Thank you,
Pasha