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 __ASM_IMAGE_H 19 #define __ASM_IMAGE_H 20 21 #ifndef LINKER_SCRIPT 22 #error This file should only be included in vmlinux.lds.S 23 #endif 24 25 /* 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. 29 */ 30 #ifdef CONFIG_CPU_BIG_ENDIAN 31 #define DATA_LE64(data) \ 32 ((((data) & 0x00000000000000ff) << 56) | \ 33 (((data) & 0x000000000000ff00) << 40) | \ 34 (((data) & 0x0000000000ff0000) << 24) | \ 35 (((data) & 0x00000000ff000000) << 8) | \ 36 (((data) & 0x000000ff00000000) >> 8) | \ 37 (((data) & 0x0000ff0000000000) >> 24) | \ 38 (((data) & 0x00ff000000000000) >> 40) | \ 39 (((data) & 0xff00000000000000) >> 56)) 40 #else 41 #define DATA_LE64(data) ((data) & 0xffffffffffffffff) 42 #endif 43 44 #ifdef CONFIG_CPU_BIG_ENDIAN 45 #define __HEAD_FLAG_BE 1 46 #else 47 #define __HEAD_FLAG_BE 0 48 #endif 49 50 #define __HEAD_FLAG_PAGE_SIZE ((PAGE_SHIFT - 10) / 2) 51 52 #define __HEAD_FLAGS ((__HEAD_FLAG_BE << 0) | \ 53 (__HEAD_FLAG_PAGE_SIZE << 1)) 54 55 /* 56 * These will output as part of the Image header, which should be little-endian 57 * regardless of the endianness of the kernel. While constant values could be 58 * endian swapped in head.S, all are done here for consistency. 59 */ 60 #define HEAD_SYMBOLS \ 61 _kernel_size_le = DATA_LE64(_end - _text); \ 62 _kernel_offset_le = DATA_LE64(TEXT_OFFSET); \ 63 _kernel_flags_le = DATA_LE64(__HEAD_FLAGS); 64 65 #ifdef CONFIG_EFI 66 67 /* 68 * Prevent the symbol aliases below from being emitted into the kallsyms 69 * table, by forcing them to be absolute symbols (which are conveniently 70 * ignored by scripts/kallsyms) rather than section relative symbols. 71 * The distinction is only relevant for partial linking, and only for symbols 72 * that are defined within a section declaration (which is not the case for 73 * the definitions below) so the resulting values will be identical. 74 */ 75 #define KALLSYMS_HIDE(sym) ABSOLUTE(sym) 76 77 /* 78 * The EFI stub has its own symbol namespace prefixed by __efistub_, to 79 * isolate it from the kernel proper. The following symbols are legally 80 * accessed by the stub, so provide some aliases to make them accessible. 81 * Only include data symbols here, or text symbols of functions that are 82 * guaranteed to be safe when executed at another offset than they were 83 * linked at. The routines below are all implemented in assembler in a 84 * position independent manner 85 */ 86 __efistub_memcmp = KALLSYMS_HIDE(__pi_memcmp); 87 __efistub_memchr = KALLSYMS_HIDE(__pi_memchr); 88 __efistub_memcpy = KALLSYMS_HIDE(__pi_memcpy); 89 __efistub_memmove = KALLSYMS_HIDE(__pi_memmove); 90 __efistub_memset = KALLSYMS_HIDE(__pi_memset); 91 __efistub_strlen = KALLSYMS_HIDE(__pi_strlen); 92 __efistub_strcmp = KALLSYMS_HIDE(__pi_strcmp); 93 __efistub_strncmp = KALLSYMS_HIDE(__pi_strncmp); 94 __efistub___flush_dcache_area = KALLSYMS_HIDE(__pi___flush_dcache_area); 95 96 #ifdef CONFIG_KASAN 97 __efistub___memcpy = KALLSYMS_HIDE(__pi_memcpy); 98 __efistub___memmove = KALLSYMS_HIDE(__pi_memmove); 99 __efistub___memset = KALLSYMS_HIDE(__pi_memset); 100 #endif 101 102 __efistub__text = KALLSYMS_HIDE(_text); 103 __efistub__end = KALLSYMS_HIDE(_end); 104 __efistub__edata = KALLSYMS_HIDE(_edata); 105 106 #endif 107 108 #endif /* __ASM_IMAGE_H */ 109