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From: mark.rutland@arm.com (Mark Rutland)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCHv6 6/8] arm64: use fixmap for text patching when text is RO
Date: Wed, 26 Nov 2014 16:18:02 +0000	[thread overview]
Message-ID: <20141126161802.GB1819@leverpostej> (raw)
In-Reply-To: <5474D056.2050101@codeaurora.org>

On Tue, Nov 25, 2014 at 06:54:14PM +0000, Laura Abbott wrote:
> On 11/25/2014 9:04 AM, Mark Rutland wrote:
> > Hi Laura,
> >
> > It looks like "early" means before we've set up the strict page
> > permissions, though as far as I can tell the fixmap will already be
> > available before we do any patching. Could we not always use the fixmap
> > for patching? Then we only need the patch_{map,unmap} additions, and not
> > the changes to distinguish the early cases.
> >
> >  From testing on Juno with defconfig, all of the early patches were
> > avoidable NOP -> NOP changes as part of static key initialisation, which
> > I think we can skip similarly to x86 (I'll send a patch shortly). All other
> > patches were not early and went via the fixmap.
> >
> > Even with the avoidable NOP -> NOP patching I did not see a noticeable
> > boot time difference from forcing the use of the fixmap.
> >
> 
> I was basing it off of the arm version which needed the early option.
> If arm64 doesn't need it I'll drop it.

Given that it only determines whether or not to use the fixmap, and we
can always use the fixmap, I think we can drop it.

Thanks,
Mark.

  reply	other threads:[~2014-11-26 16:18 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-21 21:50 [PATCHv6 0/8] Better page protections for arm64 Laura Abbott
2014-11-21 21:50 ` [PATCHv6 1/8] arm64: Treat handle_arch_irq as a function pointer Laura Abbott
2014-11-21 21:50 ` [PATCHv6 2/8] arm64: Switch to adrp for loading the stub vectors Laura Abbott
2014-11-21 21:50 ` [PATCHv6 3/8] arm64: Move cpu_resume into the text section Laura Abbott
2014-11-21 21:50 ` [PATCHv6 4/8] arm64: Move some head.text functions to executable section Laura Abbott
2014-11-26 16:30   ` Mark Rutland
2014-11-26 17:11     ` Will Deacon
2014-11-21 21:50 ` [PATCHv6 5/8] arm64: Factor out fixmap initialiation from ioremap Laura Abbott
2014-11-21 21:50 ` [PATCHv6 6/8] arm64: use fixmap for text patching when text is RO Laura Abbott
2014-11-25 17:04   ` Mark Rutland
2014-11-25 18:54     ` Laura Abbott
2014-11-26 16:18       ` Mark Rutland [this message]
2014-12-02 15:59         ` Catalin Marinas
2014-11-21 21:50 ` [PATCHv6 7/8] arm64: efi: Use ioremap_exec for code sections Laura Abbott
2014-11-25 17:26   ` Mark Rutland
2014-11-25 18:57     ` Laura Abbott
2014-12-02 17:15   ` Catalin Marinas
2014-12-02 17:20     ` Ard Biesheuvel
2014-11-21 21:50 ` [PATCHv6] arm64: add better page protections to arm64 Laura Abbott
2014-12-02 18:28   ` Catalin Marinas
2015-01-14 19:26     ` Laura Abbott
2014-11-25 15:33 ` [PATCHv6 0/8] Better page protections for arm64 Will Deacon
2014-11-25 16:32 ` Kees Cook

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