From mboxrd@z Thu Jan 1 00:00:00 1970 From: linux@arm.linux.org.uk (Russell King - ARM Linux) Date: Fri, 9 Jan 2015 16:46:08 +0000 Subject: [PATCH] arm: Remove early stack deallocation from restore_user_regs In-Reply-To: <1420470758-5874-1-git-send-email-daniel.thompson@linaro.org> References: <1418382718-16323-1-git-send-email-daniel.thompson@linaro.org> <1420470758-5874-1-git-send-email-daniel.thompson@linaro.org> Message-ID: <20150109164608.GV12302@n2100.arm.linux.org.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Jan 05, 2015 at 03:12:38PM +0000, Daniel Thompson wrote: > Currently restore_user_regs deallocates the SVC stack early in > its execution and relies on no exception being taken between > the deallocation and the registers being restored. The introduction > of a default FIQ handler that also uses the SVC stack breaks this > assumption and can result in corrupted register state. > > This patch works around the problem by removing the early > stack deallocation and using r2 as a temporary instead. I have > not found a way to do this without introducing an extra mov > instruction to the macro. > > Signed-off-by: Daniel Thompson > --- Please put it in the patch system, thanks. I think we should queue this one for stable too, as I think we need this for v3.18 (as a result of c0e7f7ee717e2b4c5791e7422424c96b5008c39e, ARM: 8150/3: fiq: Replace default FIQ handler)? -- FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up according to speedtest.net.