File 0028-arm-armv7-allow-unaligned-memory-ac.patch of Package u-boot-a20-olinuxino-lime2.16979
From 8105e402a44d836864ea23c945907d37c9fe531f Mon Sep 17 00:00:00 2001 From: Heinrich Schuchardt <xypron.glpk@gmx.de> Date: Tue, 3 Apr 2018 21:59:33 +0200 Subject: [PATCH] arm: armv7: allow unaligned memory access The UEFI spec mandates that unaligned memory access should be enabled if supported by the CPU architecture. This patch implements the function unaligned_access() to reset the aligned access flag in the system control register (SCTLR). It is called when the bootefi command is invoked. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> [agraf: fix SPDX identifier] Signed-off-by: Alexander Graf <agraf@suse.de> --- arch/arm/cpu/armv7/Makefile | 4 ++++ arch/arm/cpu/armv7/sctlr.S | 22 ++++++++++++++++++++++ 2 files changed, 26 insertions(+) create mode 100644 arch/arm/cpu/armv7/sctlr.S diff --git a/arch/arm/cpu/armv7/Makefile b/arch/arm/cpu/armv7/Makefile index b14ee54519..cdb56e490b 100644 --- a/arch/arm/cpu/armv7/Makefile +++ b/arch/arm/cpu/armv7/Makefile @@ -12,6 +12,10 @@ obj-y += cache_v7.o cache_v7_asm.o obj-y += cpu.o cp15.o obj-y += syslib.o +ifneq ($(CONFIG_SPL_BUILD),y) +obj-$(CONFIG_EFI_LOADER) += sctlr.o +endif + ifneq ($(CONFIG_SKIP_LOWLEVEL_INIT),y) obj-y += lowlevel_init.o endif diff --git a/arch/arm/cpu/armv7/sctlr.S b/arch/arm/cpu/armv7/sctlr.S new file mode 100644 index 0000000000..bd56e41afe --- /dev/null +++ b/arch/arm/cpu/armv7/sctlr.S @@ -0,0 +1,22 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * Routines to access the system control register + * + * Copyright (c) 2018 Heinrich Schuchardt + */ + +#include <linux/linkage.h> + +/* + * void allow_unaligned(void) - allow unaligned access + * + * This routine clears the aligned flag in the system control register. + * After calling this routine unaligned access does no longer lead to a + * data abort but is handled by the CPU. + */ +ENTRY(allow_unaligned) + mrc p15, 0, r0, c1, c0, 0 @ load system control register + bic r0, r0, #2 @ clear aligned flag + mcr p15, 0, r0, c1, c0, 0 @ write system control register + bx lr @ return +ENDPROC(allow_unaligned)
