1 /* 2 * Linker script macros to generate Image header fields. 3 * 4 * Copyright (C) 2014 ARM Ltd. 5 * 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. 9 * 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. 14 * 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/>. 17 */ 18 #ifndef __ARM64_KERNEL_IMAGE_H 19 #define __ARM64_KERNEL_IMAGE_H 20 21 #ifndef LINKER_SCRIPT 22 #error This file should only be included in vmlinux.lds.S 23 #endif 24 25 #include <asm/image.h> 26 27 /* 28 * There aren't any ELF relocations we can use to endian-swap values known only 29 * at link time (e.g. the subtraction of two symbol addresses), so we must get 30 * the linker to endian-swap certain values before emitting them. 31 * 32 * Note that, in order for this to work when building the ELF64 PIE executable 33 * (for KASLR), these values should not be referenced via R_AARCH64_ABS64 34 * relocations, since these are fixed up at runtime rather than at build time 35 * when PIE is in effect. So we need to split them up in 32-bit high and low 36 * words. 37 */ 38 #ifdef CONFIG_CPU_BIG_ENDIAN 39 #define DATA_LE32(data) \ 40 ((((data) & 0x000000ff) << 24) | \ 41 (((data) & 0x0000ff00) << 8) | \ 42 (((data) & 0x00ff0000) >> 8) | \ 43 (((data) & 0xff000000) >> 24)) 44 #else 45 #define DATA_LE32(data) ((data) & 0xffffffff) 46 #endif 47 48 #define DEFINE_IMAGE_LE64(sym, data) \ 49 sym##_lo32 = DATA_LE32((data) & 0xffffffff); \ 50 sym##_hi32 = DATA_LE32((data) >> 32) 51 52 #define __HEAD_FLAG(field) (__HEAD_FLAG_##field << \ 53 ARM64_IMAGE_FLAG_##field##_SHIFT) 54 55 #ifdef CONFIG_CPU_BIG_ENDIAN 56 #define __HEAD_FLAG_BE ARM64_IMAGE_FLAG_BE 57 #else 58 #define __HEAD_FLAG_BE ARM64_IMAGE_FLAG_LE 59 #endif 60 61 #define __HEAD_FLAG_PAGE_SIZE ((PAGE_SHIFT - 10) / 2) 62 63 #define __HEAD_FLAG_PHYS_BASE 1 64 65 #define __HEAD_FLAGS (__HEAD_FLAG(BE) | \ 66 __HEAD_FLAG(PAGE_SIZE) | \ 67 __HEAD_FLAG(PHYS_BASE)) 68 69 /* 70 * These will output as part of the Image header, which should be little-endian 71 * regardless of the endianness of the kernel. While constant values could be 72 * endian swapped in head.S, all are done here for consistency. 73 */ 74 #define HEAD_SYMBOLS \ 75 DEFINE_IMAGE_LE64(_kernel_size_le, _end - _text); \ 76 DEFINE_IMAGE_LE64(_kernel_offset_le, TEXT_OFFSET); \ 77 DEFINE_IMAGE_LE64(_kernel_flags_le, __HEAD_FLAGS); 78 79 #ifdef CONFIG_EFI 80 81 __efistub_stext_offset = stext - _text; 82 83 /* 84 * Prevent the symbol aliases below from being emitted into the kallsyms 85 * table, by forcing them to be absolute symbols (which are conveniently 86 * ignored by scripts/kallsyms) rather than section relative symbols. 87 * The distinction is only relevant for partial linking, and only for symbols 88 * that are defined within a section declaration (which is not the case for 89 * the definitions below) so the resulting values will be identical. 90 */ 91 #define KALLSYMS_HIDE(sym) ABSOLUTE(sym) 92 93 /* 94 * The EFI stub has its own symbol namespace prefixed by __efistub_, to 95 * isolate it from the kernel proper. The following symbols are legally 96 * accessed by the stub, so provide some aliases to make them accessible. 97 * Only include data symbols here, or text symbols of functions that are 98 * guaranteed to be safe when executed at another offset than they were 99 * linked at. The routines below are all implemented in assembler in a 100 * position independent manner 101 */ 102 __efistub_memcmp = KALLSYMS_HIDE(__pi_memcmp); 103 __efistub_memchr = KALLSYMS_HIDE(__pi_memchr); 104 __efistub_memcpy = KALLSYMS_HIDE(__pi_memcpy); 105 __efistub_memmove = KALLSYMS_HIDE(__pi_memmove); 106 __efistub_memset = KALLSYMS_HIDE(__pi_memset); 107 __efistub_strlen = KALLSYMS_HIDE(__pi_strlen); 108 __efistub_strnlen = KALLSYMS_HIDE(__pi_strnlen); 109 __efistub_strcmp = KALLSYMS_HIDE(__pi_strcmp); 110 __efistub_strncmp = KALLSYMS_HIDE(__pi_strncmp); 111 __efistub_strrchr = KALLSYMS_HIDE(__pi_strrchr); 112 __efistub___flush_dcache_area = KALLSYMS_HIDE(__pi___flush_dcache_area); 113 114 #ifdef CONFIG_KASAN 115 __efistub___memcpy = KALLSYMS_HIDE(__pi_memcpy); 116 __efistub___memmove = KALLSYMS_HIDE(__pi_memmove); 117 __efistub___memset = KALLSYMS_HIDE(__pi_memset); 118 #endif 119 120 __efistub__text = KALLSYMS_HIDE(_text); 121 __efistub__end = KALLSYMS_HIDE(_end); 122 __efistub__edata = KALLSYMS_HIDE(_edata); 123 __efistub_screen_info = KALLSYMS_HIDE(screen_info); 124 125 #endif 126 127 #endif /* __ARM64_KERNEL_IMAGE_H */ 128