From mboxrd@z Thu Jan  1 00:00:00 1970
From: linux@arm.linux.org.uk (Russell King - ARM Linux)
Date: Thu, 26 Mar 2015 12:22:04 +0000
Subject: [PATCH] ARM: force linker to use PIC veneers
In-Reply-To: <CAKv+Gu8ktOUcQrGOwMfbt8s2QG+RFdnKBykVfhXPTLSUFtWQyA@mail.gmail.com>
References: <1427192184-31261-1-git-send-email-ard.biesheuvel@linaro.org>
 <20150324122239.GB3579@e103592.cambridge.arm.com>
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 <20150324135439.GC3579@e103592.cambridge.arm.com>
 <CAKv+Gu9NeqOTjUux9S7p5o89T1tc9ACraC0D53Y=CCTNzZXKMg@mail.gmail.com>
 <20150325104603.GA3560@e103592.cambridge.arm.com>
 <20150326113648.GC8656@n2100.arm.linux.org.uk>
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Message-ID: <20150326122203.GG8656@n2100.arm.linux.org.uk>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Thu, Mar 26, 2015 at 01:20:16PM +0100, Ard Biesheuvel wrote:
> On 26 March 2015 at 12:36, Russell King - ARM Linux
> <linux@arm.linux.org.uk> wrote:
> > On Wed, Mar 25, 2015 at 10:46:14AM +0000, Dave Martin wrote:
> >> Hmmm, you seem to be right.
> >>
> >> Thumb has no bx <label> instruction, and veneers introduced by ld are
> >> always ARM code, so this looks tricky to avoid without patching ld.
> >>
> >> As you observe, this only impacts large kernels anyway.
> >>
> >> So,
> >>
> >> Reviewed-by: Dave Martin <Dave.Martin@arm.com>
> >
> > Someone needs to check what the result is like for older CPUs too.
> >
> 
> Any specific concerns? The --pic-veneer switch dates back to 2009, so
> it's been around for a while

BX.  Not every CPU supports BX.

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