blob: 37bb6a567e8855fc841e016788211e7cf0f6944b [file] [log] [blame]
Matt Porterbd1fef52015-05-05 15:00:23 -04001/*
2 * (C) Copyright 2008-2011
3 * Graeme Russ, <graeme.russ@gmail.com>
4 *
5 * (C) Copyright 2002
6 * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
7 *
8 * (C) Copyright 2002
9 * Wolfgang Denk, DENX Software Engineering, <wd@denx.de>
10 *
11 * (C) Copyright 2002
12 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
13 * Marius Groeger <mgroeger@sysgo.de>
14 *
15 * Copyright 2015 ATS Advanced Telematics Systems GmbH
16 * Copyright 2015 Konsulko Group, Matt Porter <mporter@konsulko.com>
17 *
18 * SPDX-License-Identifier: GPL-2.0+
19 */
20
21#include <common.h>
22#include <command.h>
23
24DECLARE_GLOBAL_DATA_PTR;
25
26/*
27 * ARMv7M does not support ARM instruction mode. However, the
28 * interworking BLX and BX instructions do encode the ARM/Thumb
29 * field in bit 0. This means that when executing any Branch
30 * and eXchange instruction we must set bit 0 to one to guarantee
31 * that we keep the processor in Thumb instruction mode. From The
32 * ARMv7-M Instruction Set A4.1.1:
33 * "ARMv7-M only supports the Thumb instruction execution state,
34 * therefore the value of address bit [0] must be 1 in interworking
35 * instructions, otherwise a fault occurs."
36 */
37unsigned long do_go_exec(ulong (*entry)(int, char * const []),
38 int argc, char * const argv[])
39{
40 ulong addr = (ulong)entry | 1;
41 entry = (void *)addr;
42
43 return entry(argc, argv);
44}