u-boot/arch/arm/cpu/armv7/sctlr.S
Marek Vasut c32248601c ARM: armv7: Add C wrapper for allow_unaligned()
Rename current assembler implementation of allow_unaligned() to
v7_arch_cp15_allow_unaligned() and add it into armv7.h header,
then add C wrapper of allow_unaligned().

This fixes misbehavior when linking U-Boot on ARMv7a i.MX6Q, where the
CPU specific allow_unaligned() implementation was ignored and instead the
__weak allow_unaligned() implementation from lib/efi_loader/efi_setup.c
was used, which led to "data abort" just before booting Linux via tftp,
in efi_dp_from_file() -> path_to_uefi() -> utf16_put() .

The problem is triggerd by c7c0ca3767 ("efi_loader: fix efi_dp_from_file()") .
Adding the wrapper fixes the problem.

Fixes: 78f90aaeec ("arm: armv7: allow unaligned memory access")
Signed-off-by: Marek Vasut <marex@denx.de>
2023-07-01 17:29:15 +02:00

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ArmAsm

/* SPDX-License-Identifier: GPL-2.0+ */
/*
* Routines to access the system control register
*
* Copyright (c) 2018 Heinrich Schuchardt
*/
#include <linux/linkage.h>
/*
* void v7_arch_cp15_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(v7_arch_cp15_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(v7_arch_cp15_allow_unaligned)