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u-boot/arch/arm/cpu/arm11/sctlr.S
Marek Vasut 2b17dd1d9d ARM: arm11: Add C wrapper for allow_unaligned()
Rename current assembler implementation of allow_unaligned() to
arm11_arch_cp15_allow_unaligned() and add it into arm11.h header,
then add C wrapper of allow_unaligned().

This fixes misbehavior when linking U-Boot, 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: d47a774680 ("arm: arm11: allow unaligned memory access")
Signed-off-by: Marek Vasut <marex@denx.de>
2023-07-01 17:29:15 +02:00

25 lines
892 B
ArmAsm

/* SPDX-License-Identifier: GPL-2.0+ */
/*
* Routines to access the system control register
*
* Copyright (c) 2019 Heinrich Schuchardt
*/
#include <linux/linkage.h>
/*
* void arm11_arch_cp15_allow_unaligned(void) - allow unaligned access
*
* This routine sets the enable unaligned data support flag and clears the
* aligned flag in the system control register.
* After calling this routine unaligned access does no longer leads to a
* data abort or undefined behavior but is handled by the CPU.
* For details see the "ARM Architecture Reference Manual" for ARMv6.
*/
ENTRY(arm11_arch_cp15_allow_unaligned)
mrc p15, 0, r0, c1, c0, 0 @ load system control register
orr r0, r0, #1 << 22 @ set unaligned data support flag
bic r0, r0, #2 @ clear aligned flag
mcr p15, 0, r0, c1, c0, 0 @ write system control register
bx lr @ return
ENDPROC(arm11_arch_cp15_allow_unaligned)