1 /* SPDX-License-Identifier: GPL-2.0+ */ 2 /* 3 * Symbol access for symbols set up by binman as part of the build. 4 * 5 * This allows C code to access the position of a particular part of the image 6 * assembled by binman. 7 * 8 * Copyright (c) 2017 Google, Inc 9 */ 10 11 #ifndef __BINMAN_SYM_H 12 #define __BINMAN_SYM_H 13 14 /* BSYM in little endian, keep in sync with tools/binman/elf.py */ 15 #define BINMAN_SYM_MAGIC_VALUE (0x4d595342UL) 16 #define BINMAN_SYM_MISSING (-1UL) 17 18 #if CONFIG_IS_ENABLED(BINMAN_SYMBOLS) 19 20 /** 21 * binman_symname() - Internal function to get a binman symbol name 22 * 23 * @entry_name: Name of the entry to look for (e.g. 'u_boot_spl') 24 * @_prop_name: Property value to get from that entry (e.g. 'pos') 25 * @returns name of the symbol for that entry and property 26 */ 27 #define binman_symname(_entry_name, _prop_name) \ 28 _binman_ ## _entry_name ## _prop_ ## _prop_name 29 30 /** 31 * binman_sym_declare() - Declare a symbol that will be used at run-time 32 * 33 * @_type: Type f the symbol (e.g. unsigned long) 34 * @entry_name: Name of the entry to look for (e.g. 'u_boot_spl') 35 * @_prop_name: Property value to get from that entry (e.g. 'pos') 36 */ 37 #define binman_sym_declare(_type, _entry_name, _prop_name) \ 38 _type binman_symname(_entry_name, _prop_name) \ 39 __attribute__((aligned(4), unused, section(".binman_sym"))) 40 41 /** 42 * binman_sym_extern() - Declare a extern symbol that will be used at run-time 43 * 44 * @_type: Type f the symbol (e.g. unsigned long) 45 * @entry_name: Name of the entry to look for (e.g. 'u_boot_spl') 46 * @_prop_name: Property value to get from that entry (e.g. 'pos') 47 */ 48 #define binman_sym_extern(_type, _entry_name, _prop_name) \ 49 extern _type binman_symname(_entry_name, _prop_name) \ 50 __attribute__((aligned(4), unused, section(".binman_sym"))) 51 52 /** 53 * binman_sym_declare_optional() - Declare an optional symbol 54 * 55 * If this symbol cannot be provided by binman, an error will not be generated. 56 * Instead the image will be assigned the value BINMAN_SYM_MISSING. 57 * 58 * @_type: Type f the symbol (e.g. unsigned long) 59 * @entry_name: Name of the entry to look for (e.g. 'u_boot_spl') 60 * @_prop_name: Property value to get from that entry (e.g. 'pos') 61 */ 62 #define binman_sym_declare_optional(_type, _entry_name, _prop_name) \ 63 _type binman_symname(_entry_name, _prop_name) \ 64 __attribute__((aligned(4), weak, unused, \ 65 section(".binman_sym"))) 66 67 /** 68 * _binman_sym_magic - Internal magic symbol for validity checks 69 * 70 * When building images, binman fills in this symbol with the magic 71 * value #defined above. This is used to check at runtime if the 72 * symbol values were filled in and are OK to use. 73 */ 74 extern unsigned long _binman_sym_magic; 75 76 /** 77 * DECLARE_BINMAN_MAGIC_SYM - Declare the internal magic symbol 78 * 79 * This macro declares the _binman_sym_magic symbol so that it exists. 80 * Declaring it here would cause errors during linking due to multiple 81 * definitions of the symbol. 82 */ 83 #define DECLARE_BINMAN_MAGIC_SYM \ 84 unsigned long _binman_sym_magic \ 85 __attribute__((aligned(4), section(".binman_sym"))) 86 87 /** 88 * BINMAN_SYMS_OK - Check if the symbol values are valid 89 * 90 * This macro checks if the magic symbol's value is filled properly, 91 * which indicates that other symbols are OK to use as well. 92 * 93 * Return: 1 if binman symbol values are usable, 0 if not 94 */ 95 #define BINMAN_SYMS_OK \ 96 (*(unsigned long *)&_binman_sym_magic == BINMAN_SYM_MAGIC_VALUE) 97 98 /** 99 * binman_sym() - Access a previously declared symbol 100 * 101 * This is used to get the value of a symbol. E.g.: 102 * 103 * unsigned long address = binman_sym(unsigned long, u_boot_spl, pos); 104 * 105 * @_type: Type f the symbol (e.g. unsigned long) 106 * @entry_name: Name of the entry to look for (e.g. 'u_boot_spl') 107 * @_prop_name: Property value to get from that entry (e.g. 'pos') 108 * 109 * Return: value of that property (filled in by binman), or 110 * BINMAN_SYM_MISSING if the value is unavailable 111 */ 112 #define binman_sym(_type, _entry_name, _prop_name) \ 113 (BINMAN_SYMS_OK ? \ 114 (*(_type *)&binman_symname(_entry_name, _prop_name)) : \ 115 BINMAN_SYM_MISSING) 116 117 #else /* !CONFIG_IS_ENABLED(BINMAN_SYMBOLS) */ 118 119 #define binman_sym_declare(_type, _entry_name, _prop_name) 120 121 #define binman_sym_declare_optional(_type, _entry_name, _prop_name) 122 123 #define binman_sym_extern(_type, _entry_name, _prop_name) 124 125 #define DECLARE_BINMAN_MAGIC_SYM 126 127 #define BINMAN_SYMS_OK (0) 128 129 #define binman_sym(_type, _entry_name, _prop_name) BINMAN_SYM_MISSING 130 131 #endif /* CONFIG_IS_ENABLED(BINMAN_SYMBOLS) */ 132 133 #endif 134