uboot/u-boot-stm32mp-2020.01/arch/arm/lib/cmd_boot.c

42 lines
1.3 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2008-2011
* Graeme Russ, <graeme.russ@gmail.com>
*
* (C) Copyright 2002
* Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
*
* (C) Copyright 2002
* Wolfgang Denk, DENX Software Engineering, <wd@denx.de>
*
* (C) Copyright 2002
* Sysgo Real-Time Solutions, GmbH <www.elinos.com>
* Marius Groeger <mgroeger@sysgo.de>
*
* Copyright 2015 ATS Advanced Telematics Systems GmbH
* Copyright 2015 Konsulko Group, Matt Porter <mporter@konsulko.com>
*/
#include <common.h>
#include <command.h>
/*
* ARMv7M does not support ARM instruction mode. However, the
* interworking BLX and BX instructions do encode the ARM/Thumb
* field in bit 0. This means that when executing any Branch
* and eXchange instruction we must set bit 0 to one to guarantee
* that we keep the processor in Thumb instruction mode. From The
* ARMv7-M Instruction Set A4.1.1:
* "ARMv7-M only supports the Thumb instruction execution state,
* therefore the value of address bit [0] must be 1 in interworking
* instructions, otherwise a fault occurs."
*/
unsigned long do_go_exec(ulong (*entry)(int, char * const []),
int argc, char * const argv[])
{
ulong addr = (ulong)entry | 1;
entry = (void *)addr;
return entry(argc, argv);
}