2 * Linker script macros to generate Image header fields.
4 * Copyright (C) 2014 ARM Ltd.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
22 #error This file should only be included in vmlinux.lds.S
26 * There aren't any ELF relocations we can use to endian-swap values known only
27 * at link time (e.g. the subtraction of two symbol addresses), so we must get
28 * the linker to endian-swap certain values before emitting them.
30 * Note that, in order for this to work when building the ELF64 PIE executable
31 * (for KASLR), these values should not be referenced via R_AARCH64_ABS64
32 * relocations, since these are fixed up at runtime rather than at build time
33 * when PIE is in effect. So we need to split them up in 32-bit high and low
36 #ifdef CONFIG_CPU_BIG_ENDIAN
37 #define DATA_LE32(data) \
38 ((((data) & 0x000000ff) << 24) | \
39 (((data) & 0x0000ff00) << 8) | \
40 (((data) & 0x00ff0000) >> 8) | \
41 (((data) & 0xff000000) >> 24))
43 #define DATA_LE32(data) ((data) & 0xffffffff)
46 #define DEFINE_IMAGE_LE64(sym, data) \
47 sym##_lo32 = DATA_LE32((data) & 0xffffffff); \
48 sym##_hi32 = DATA_LE32((data) >> 32)
50 #ifdef CONFIG_CPU_BIG_ENDIAN
51 #define __HEAD_FLAG_BE 1
53 #define __HEAD_FLAG_BE 0
56 #define __HEAD_FLAG_PAGE_SIZE ((PAGE_SHIFT - 10) / 2)
58 #define __HEAD_FLAG_PHYS_BASE 1
60 #define __HEAD_FLAGS ((__HEAD_FLAG_BE << 0) | \
61 (__HEAD_FLAG_PAGE_SIZE << 1) | \
62 (__HEAD_FLAG_PHYS_BASE << 3))
65 * These will output as part of the Image header, which should be little-endian
66 * regardless of the endianness of the kernel. While constant values could be
67 * endian swapped in head.S, all are done here for consistency.
69 #define HEAD_SYMBOLS \
70 DEFINE_IMAGE_LE64(_kernel_size_le, _end - _text); \
71 DEFINE_IMAGE_LE64(_kernel_offset_le, TEXT_OFFSET); \
72 DEFINE_IMAGE_LE64(_kernel_flags_le, __HEAD_FLAGS);
77 * Use ABSOLUTE() to avoid ld.lld treating this as a relative symbol:
78 * https://github.com/ClangBuiltLinux/linux/issues/561
80 __efistub_stext_offset = ABSOLUTE(stext - _text);
83 * The EFI stub has its own symbol namespace prefixed by __efistub_, to
84 * isolate it from the kernel proper. The following symbols are legally
85 * accessed by the stub, so provide some aliases to make them accessible.
86 * Only include data symbols here, or text symbols of functions that are
87 * guaranteed to be safe when executed at another offset than they were
88 * linked at. The routines below are all implemented in assembler in a
89 * position independent manner
91 __efistub_memcmp = __pi_memcmp;
92 __efistub_memchr = __pi_memchr;
93 __efistub_memcpy = __pi_memcpy;
94 __efistub_memmove = __pi_memmove;
95 __efistub_memset = __pi_memset;
96 __efistub_strlen = __pi_strlen;
97 __efistub_strnlen = __pi_strnlen;
98 __efistub_strcmp = __pi_strcmp;
99 __efistub_strncmp = __pi_strncmp;
100 __efistub_strrchr = __pi_strrchr;
101 __efistub___flush_dcache_area = __pi___flush_dcache_area;
104 __efistub___memcpy = __pi_memcpy;
105 __efistub___memmove = __pi_memmove;
106 __efistub___memset = __pi_memset;
109 __efistub__text = _text;
110 __efistub__end = _end;
111 __efistub__edata = _edata;
112 __efistub_screen_info = screen_info;
116 #endif /* __ASM_IMAGE_H */