u-boot/arch/arm/lib/setjmp.S
Sergei Antonov 583f1b2f10 arm: ARMv4 assembly compatibility
There is currently a problem that U-Boot can not work on ARMv4
because assembly imlementations of memcpy() and some other functions
use "bx lr" instruction that is not available on ARMv4 ("mov pc, lr"
should be used instead).

A working preprocessor-based solution to this problem is found in
arch/arm/lib/relocate.S. Move it to the "ret" macro in
arch/arm/include/asm/assembler.h and change all "bx lr" code
to "ret lr" in functions that may run on ARMv4. Linux source code
deals with this problem in the same manner.

v1 -> v2:
Comment update. Pointed out by Andre Przywara.

Signed-off-by: Sergei Antonov <saproj@gmail.com>
CC: Samuel Holland <samuel@sholland.org>
CC: Ye Li <ye.li@nxp.com>
CC: Simon Glass <sjg@chromium.org>
CC: Andre Przywara <andre.przywara@arm.com>
CC: Marek Vasut <marex@denx.de>
CC: Sean Anderson <sean.anderson@seco.com>
CC: Tom Rini <trini@konsulko.com>
2022-09-02 13:40:42 -04:00

36 lines
730 B
ArmAsm

/* SPDX-License-Identifier: GPL-2.0+ */
/*
* (C) 2017 Theobroma Systems Design und Consulting GmbH
*/
#include <config.h>
#include <asm/assembler.h>
#include <linux/linkage.h>
.pushsection .text.setjmp, "ax"
ENTRY(setjmp)
/*
* A subroutine must preserve the contents of the registers
* r4-r8, r10, r11 (v1-v5, v7 and v8) and SP (and r9 in PCS
* variants that designate r9 as v6).
*/
mov ip, sp
stm a1, {v1-v8, ip, lr}
mov a1, #0
ret lr
ENDPROC(setjmp)
.popsection
.pushsection .text.longjmp, "ax"
ENTRY(longjmp)
ldm a1, {v1-v8, ip, lr}
mov sp, ip
mov a1, a2
/* If we were passed a return value of zero, return one instead */
cmp a1, #0
bne 1f
mov a1, #1
1:
ret lr
ENDPROC(longjmp)
.popsection