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 * 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 34 * words. 35 */ 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)) 42 #else 43 #define DATA_LE32(data) ((data) & 0xffffffff) 44 #endif 45 46 #define DEFINE_IMAGE_LE64(sym, data) \ 47 sym##_lo32 = DATA_LE32((data) & 0xffffffff); \ 48 sym##_hi32 = DATA_LE32((data) >> 32) 49 50 #ifdef CONFIG_CPU_BIG_ENDIAN 51 #define __HEAD_FLAG_BE 1 52 #else 53 #define __HEAD_FLAG_BE 0 54 #endif 55 56 #define __HEAD_FLAG_PAGE_SIZE ((PAGE_SHIFT - 10) / 2) 57 58 #define __HEAD_FLAG_PHYS_BASE 1 59 60 #define __HEAD_FLAGS ((__HEAD_FLAG_BE << 0) | \ 61 (__HEAD_FLAG_PAGE_SIZE << 1) | \ 62 (__HEAD_FLAG_PHYS_BASE << 3)) 63 64 /* 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. 68 */ 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); 73 74 #ifdef CONFIG_EFI 75 76 __efistub_stext_offset = stext - _text; 77 78 /* 79 * The EFI stub has its own symbol namespace prefixed by __efistub_, to 80 * isolate it from the kernel proper. The following symbols are legally 81 * accessed by the stub, so provide some aliases to make them accessible. 82 * Only include data symbols here, or text symbols of functions that are 83 * guaranteed to be safe when executed at another offset than they were 84 * linked at. The routines below are all implemented in assembler in a 85 * position independent manner 86 */ 87 __efistub_memcmp = __pi_memcmp; 88 __efistub_memchr = __pi_memchr; 89 __efistub_memcpy = __pi_memcpy; 90 __efistub_memmove = __pi_memmove; 91 __efistub_memset = __pi_memset; 92 __efistub_strlen = __pi_strlen; 93 __efistub_strnlen = __pi_strnlen; 94 __efistub_strcmp = __pi_strcmp; 95 __efistub_strncmp = __pi_strncmp; 96 __efistub_strrchr = __pi_strrchr; 97 __efistub___flush_dcache_area = __pi___flush_dcache_area; 98 99 #ifdef CONFIG_KASAN 100 __efistub___memcpy = __pi_memcpy; 101 __efistub___memmove = __pi_memmove; 102 __efistub___memset = __pi_memset; 103 #endif 104 105 __efistub__text = _text; 106 __efistub__end = _end; 107 __efistub__edata = _edata; 108 __efistub_screen_info = screen_info; 109 110 #endif 111 112 #endif /* __ASM_IMAGE_H */ 113