1/*
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright © 2022 Keith Packard
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above
14 *    copyright notice, this list of conditions and the following
15 *    disclaimer in the documentation and/or other materials provided
16 *    with the distribution.
17 *
18 * 3. Neither the name of the copyright holder nor the names of its
19 *    contributors may be used to endorse or promote products derived
20 *    from this software without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
25 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
26 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
27 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
28 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
29 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
31 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
32 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
33 * OF THE POSSIBILITY OF SUCH DAMAGE.
34 */
35#define PPC_BIT(bit)            (0x8000000000000000ULL >> (bit))
36	.text
37	.section	.text.init.enter
38	.global _start
39	.type	_start, @function
40_start:
41
42	/* Where are we? */
43	bl	here
44here:	mflr	%r2
45
46	/* Get stack pointer */
47	addi	%r1,%r2,stackaddr - here
48	ld	%r1,0(%r1)
49
50#ifdef __PPC64__
51	/* Figure out the initial TOC value */
52	addi	%r2,%r2,toc-here
53	ld	%r2,0(%r2)
54#endif
55
56	mfmsr	%r0
57	/* Enable FPU */
58	ori	%r0,%r0,PPC_BIT(50)
59	/* Enable VSX */
60	oris	%r0,%r0,PPC_BIT(40)>>16
61	/* Enable Altivec */
62	oris	%r0,%r0,PPC_BIT(38)>>16
63	mtmsr	%r0
64
65	/*
66	 *   r8 is the OPAL base
67	 *   r9 is the OPAL entry point point
68	 */
69	mr	%r3, %r8
70	mr	%r4, %r9
71	bl	_cstart
72	.align	3
73#ifdef __PPC64__
74toc:
75	.quad 	.TOC.@tocbase
76
77stackaddr:
78	.quad	__stack
79
80#else
81stackaddr:
82	.long	__stack
83#endif
84
85