start.S revision 344409 
1/*-
2 * Copyright (c) 2014 Andrew Turner
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: stable/11/stand/efi/loader/arch/arm64/start.S 344409 2019-02-21 02:46:32Z kevans $
27 */
28
29/*
30 * We need to be a PE32+ file for EFI. On some architectures we can use
31 * objcopy to create the correct file, however on arm64 we need to do
32 * it ourselves.
33 */
34
35#define	IMAGE_FILE_MACHINE_ARM64	0xaa64
36
37#define	IMAGE_SCN_CNT_CODE		0x00000020
38#define	IMAGE_SCN_CNT_INITIALIZED_DATA	0x00000040
39#define	IMAGE_SCN_MEM_DISCARDABLE	0x02000000
40#define	IMAGE_SCN_MEM_EXECUTE		0x20000000
41#define	IMAGE_SCN_MEM_READ		0x40000000
42
43	.section .peheader,"a"
44efi_start:
45	/* The MS-DOS Stub, only used to get the offset of the COFF header */
46	.ascii	"MZ"
47	.short	0
48	.space	0x38
49	.long	pe_sig - efi_start
50
51	/* The PE32 Signature. Needs to be 8-byte aligned */
52	.align	3
53pe_sig:
54	.ascii	"PE"
55	.short	0
56coff_head:
57	.short	IMAGE_FILE_MACHINE_ARM64	/* AArch64 file */
58	.short	2				/* 2 Sections */
59	.long	0				/* Timestamp */
60	.long	0				/* No symbol table */
61	.long	0				/* No symbols */
62	.short	section_table - optional_header	/* Optional header size */
63	.short	0	/* Characteristics TODO: Fill in */
64
65optional_header:
66	.short	0x020b				/* PE32+ (64-bit addressing) */
67	.byte	0				/* Major linker version */
68	.byte	0				/* Minor linker version */
69	.long	_edata - _end_header		/* Code size */
70	.long	0				/* No initialized data */
71	.long	0				/* No uninitialized data */
72	.long	_start - efi_start		/* Entry point */
73	.long	_end_header - efi_start		/* Start of code */
74
75optional_windows_header:
76	.quad	0				/* Image base */
77	.long	32				/* Section Alignment */
78	.long	8				/* File alignment */
79	.short	0				/* Major OS version */
80	.short	0				/* Minor OS version */
81	.short	0				/* Major image version */
82	.short	0				/* Minor image version */
83	.short	0				/* Major subsystem version */
84	.short	0				/* Minor subsystem version */
85	.long	0				/* Win32 version */
86	.long	_edata - efi_start		/* Image size */
87	.long	_end_header - efi_start		/* Header size */
88	.long	0				/* Checksum */
89	.short	0xa				/* Subsystem (EFI app) */
90	.short	0				/* DLL Characteristics */
91	.quad	0				/* Stack reserve */
92	.quad	0				/* Stack commit */
93	.quad	0				/* Heap reserve */
94	.quad	0				/* Heap commit */
95	.long	0				/* Loader flags */
96	.long	6				/* Number of RVAs */
97
98	/* RVAs: */
99	.quad	0
100	.quad	0
101	.quad	0
102	.quad	0
103	.quad	0
104	.quad	0
105
106section_table:
107	/* We need a .reloc section for EFI */
108	.ascii	".reloc"
109	.byte	0
110	.byte	0				/* Pad to 8 bytes */
111	.long	0				/* Virtual size */
112	.long	0				/* Virtual address */
113	.long	0				/* Size of raw data */
114	.long	0				/* Pointer to raw data */
115	.long	0				/* Pointer to relocations */
116	.long	0				/* Pointer to line numbers */
117	.short	0				/* Number of relocations */
118	.short	0				/* Number of line numbers */
119	.long	(IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ | \
120		 IMAGE_SCN_MEM_DISCARDABLE)	/* Characteristics */
121
122	/* The contents of the loader */
123	.ascii	".text"
124	.byte	0
125	.byte	0
126	.byte	0				/* Pad to 8 bytes */
127	.long	_edata - _end_header		/* Virtual size */
128	.long	_end_header - efi_start		/* Virtual address */
129	.long	_edata - _end_header		/* Size of raw data */
130	.long	_end_header - efi_start		/* Pointer to raw data */
131	.long	0				/* Pointer to relocations */
132	.long	0				/* Pointer to line numbers */
133	.short	0				/* Number of relocations */
134	.short	0				/* Number of line numbers */
135	.long	(IMAGE_SCN_CNT_CODE | IMAGE_SCN_MEM_EXECUTE | \
136		 IMAGE_SCN_MEM_READ)		/* Characteristics */
137_end_header:
138
139	.text
140	.globl	_start
141_start:
142	/* Save the boot params to the stack */
143	stp	x0, x1, [sp, #-16]!
144
145	adr	x0, __bss_start
146	adr	x1, __bss_end
147
148	b 2f
149
1501:
151	stp	xzr, xzr, [x0], #16
1522:
153	cmp	x0, x1
154	b.lo	1b
155
156	adr	x0, ImageBase
157	adr	x1, _DYNAMIC
158
159	bl	self_reloc
160
161	ldp	x0, x1, [sp], #16
162
163#ifndef EFI_BOOT1
164	/*
165	 * Load the stack to use. The default stack may be too small for
166	 * the lua loader.
167	 */
168	adr	x2, initstack_end
169	mov	sp, x2
170#endif
171
172	bl	efi_main
173
1741:	b	1b
175
176#ifndef EFI_BOOT1
177.bss
178	.align	4
179initstack:
180	.space	(64 * 1024)
181initstack_end:
182#endif
183