1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Linker script macros to generate Image header fields.
4  *
5  * Copyright (C) 2014 ARM Ltd.
6  */
7 #ifndef __ARM64_KERNEL_IMAGE_H
8 #define __ARM64_KERNEL_IMAGE_H
9 
10 #ifndef LINKER_SCRIPT
11 #error This file should only be included in vmlinux.lds.S
12 #endif
13 
14 #include <asm/image.h>
15 
16 /*
17  * There aren't any ELF relocations we can use to endian-swap values known only
18  * at link time (e.g. the subtraction of two symbol addresses), so we must get
19  * the linker to endian-swap certain values before emitting them.
20  *
21  * Note that, in order for this to work when building the ELF64 PIE executable
22  * (for KASLR), these values should not be referenced via R_AARCH64_ABS64
23  * relocations, since these are fixed up at runtime rather than at build time
24  * when PIE is in effect. So we need to split them up in 32-bit high and low
25  * words.
26  */
27 #ifdef CONFIG_CPU_BIG_ENDIAN
28 #define DATA_LE32(data)				\
29 	((((data) & 0x000000ff) << 24) |	\
30 	 (((data) & 0x0000ff00) << 8)  |	\
31 	 (((data) & 0x00ff0000) >> 8)  |	\
32 	 (((data) & 0xff000000) >> 24))
33 #else
34 #define DATA_LE32(data) ((data) & 0xffffffff)
35 #endif
36 
37 #define DEFINE_IMAGE_LE64(sym, data)				\
38 	sym##_lo32 = DATA_LE32((data) & 0xffffffff);		\
39 	sym##_hi32 = DATA_LE32((data) >> 32)
40 
41 #define __HEAD_FLAG(field)	(__HEAD_FLAG_##field << \
42 					ARM64_IMAGE_FLAG_##field##_SHIFT)
43 
44 #ifdef CONFIG_CPU_BIG_ENDIAN
45 #define __HEAD_FLAG_BE		ARM64_IMAGE_FLAG_BE
46 #else
47 #define __HEAD_FLAG_BE		ARM64_IMAGE_FLAG_LE
48 #endif
49 
50 #define __HEAD_FLAG_PAGE_SIZE	((PAGE_SHIFT - 10) / 2)
51 
52 #define __HEAD_FLAG_PHYS_BASE	1
53 
54 #define __HEAD_FLAGS		(__HEAD_FLAG(BE)	| \
55 				 __HEAD_FLAG(PAGE_SIZE) | \
56 				 __HEAD_FLAG(PHYS_BASE))
57 
58 /*
59  * These will output as part of the Image header, which should be little-endian
60  * regardless of the endianness of the kernel. While constant values could be
61  * endian swapped in head.S, all are done here for consistency.
62  */
63 #define HEAD_SYMBOLS						\
64 	DEFINE_IMAGE_LE64(_kernel_size_le, _end - _text);	\
65 	DEFINE_IMAGE_LE64(_kernel_flags_le, __HEAD_FLAGS);
66 
67 #endif /* __ARM64_KERNEL_IMAGE_H */
68