Commit 7710cc69 authored Dec 01, 2017 by Vladimir Murzin Committed by Russell King Dec 17, 2017

ARM: 8732/1: NOMMU: Allow userspace to access background MPU region



Currently, with MPU enabled, we prohibit userspace access to anything
except RAM. Benjamin, reported that because of that his userspace
application cannot access framebuffer's memory he reserved in device
tree. It turns out we have no option other than to allow userspace
access memory covered by background region.

Reported-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

parent 7e19092f

arch/arm/mm/pmsa-v7.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -433,7 +433,7 @@ void __init mpu_setup(void)

		/* Background */
		err \|= mpu_setup_region(region++, 0, 32,
		MPU_ACR_XN \| MPU_RGN_STRONGLY_ORDERED \| MPU_AP_PL1RW_PL0NA,
		MPU_ACR_XN \| MPU_RGN_STRONGLY_ORDERED \| MPU_AP_PL1RW_PL0RW,
		0, false);

		#ifdef CONFIG_XIP_KERNEL

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