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>
This commit is contained in:
Vladimir Murzin 2017-12-01 10:19:11 +01:00 committed by Russell King
parent 7e19092f60
commit 7710cc691c

View file

@ -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