From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave.Martin@arm.com (Dave P Martin) Date: Thu, 26 Mar 2015 12:53:35 +0000 Subject: [PATCH] ARM: force linker to use PIC veneers In-Reply-To: References: <1427192184-31261-1-git-send-email-ard.biesheuvel@linaro.org> <20150324122239.GB3579@e103592.cambridge.arm.com> <20150324135439.GC3579@e103592.cambridge.arm.com> <20150325104603.GA3560@e103592.cambridge.arm.com> <20150326113648.GC8656@n2100.arm.linux.org.uk> <20150326122203.GG8656@n2100.arm.linux.org.uk> Message-ID: <20150326125334.GA27016@e103592.cambridge.arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Mar 26, 2015 at 12:24:01PM +0000, Ard Biesheuvel wrote: > On 26 March 2015 at 13:22, Russell King - ARM Linux > wrote: > > On Thu, Mar 26, 2015 at 01:20:16PM +0100, Ard Biesheuvel wrote: [...] > >> 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. > > > > The bx is used for the Thumb -> ARM switch inside the veneer only, so > if you build for ARM these won't appear in the output Agreed that's what's _supposed_ to happen. Note that --use-blx is an override and might introduce BXs into a kernel that otherwise doesn't have them. But in any case, this option doesn't show a benefit for the scenario under discussion, hence my dropping the request (conditional on THUMB2_KERNEL in any case). Ard, can you should build a couple of !THUMB2_KERNEL/pre-v5 configurations with your change and check, just to be sure? Cheers ---Dave