152928Sjb/* $NetBSD$ */ 252928Sjb 3161560Smarcel/* 4161560Smarcel * Function calling ABI conversion from Linux to EFI for x86_64 5107508Sobrien * 6107508Sobrien * Copyright (C) 2007 Intel Corp 7131832Sobrien * Bibo Mao <bibo.mao@intel.com> 896783Sobrien * Huang Ying <ying.huang@intel.com> 996783Sobrien * Copyright (C) 2012 Felipe Contreras <felipe.contreras@gmail.com> 1096783Sobrien */ 1184902Sobrien 1284902Sobrien#if !defined(HAVE_USE_MS_ABI) 1384902Sobrien/* 1484902Sobrien * EFI calling conventions are documented at: 15131832Sobrien * http://msdn.microsoft.com/en-us/library/ms235286%28v=vs.80%29.aspx 16131832Sobrien * ELF calling conventions are documented at: 17107508Sobrien * http://www.x86-64.org/documentation/abi.pdf 1884902Sobrien * 1984902Sobrien * Basically here are the conversion rules: 20 * a) our function pointer is in %rdi 21 * b) rsi through r8 (elf) aka rcx through r9 (ms) require stack space 22 * on the MS side even though it's not getting used at all. 23 * c) 8(%rsp) is always aligned to 16 in ELF, so %rsp is shifted 8 bytes extra 24 * d) arguments are as follows: (elf -> ms) 25 * 1) rdi -> rcx (32 saved) 26 * 2) rsi -> rdx (32 saved) 27 * 3) rdx -> r8 (32 saved) 28 * 4) rcx -> r9 (32 saved) 29 * 5) r8 -> 32(%rsp) (32 saved) 30 * 6) r9 -> 40(%rsp) (48 saved) 31 * 7) 8(%rsp) -> 48(%rsp) (48 saved) 32 * 8) 16(%rsp) -> 56(%rsp) (64 saved) 33 * 9) 24(%rsp) -> 64(%rsp) (64 saved) 34 * 10) 32(%rsp) -> 72(%rsp) (80 saved) 35 * e) because the first argument we recieve in a thunker is actually the 36 * function to be called, arguments are offset as such: 37 * 0) rdi -> caller 38 * 1) rsi -> rcx (32 saved) 39 * 2) rdx -> rdx (32 saved) 40 * 3) rcx -> r8 (32 saved) 41 * 4) r8 -> r9 (32 saved) 42 * 5) r9 -> 32(%rsp) (32 saved) 43 * 6) 8(%rsp) -> 40(%rsp) (48 saved) 44 * 7) 16(%rsp) -> 48(%rsp) (48 saved) 45 * 8) 24(%rsp) -> 56(%rsp) (64 saved) 46 * 9) 32(%rsp) -> 64(%rsp) (64 saved) 47 * 10) 40(%rsp) -> 72(%rsp) (80 saved) 48 * f) arguments need to be moved in opposite order to avoid clobbering 49 */ 50 51#define ENTRY(name) \ 52 .globl name; \ 53 name: 54 55ENTRY(efi_call0) 56 subq $40, %rsp 57 call *%rdi 58 addq $40, %rsp 59 ret 60 61ENTRY(efi_call1) 62 subq $40, %rsp 63 mov %rsi, %rcx 64 call *%rdi 65 addq $40, %rsp 66 ret 67 68ENTRY(efi_call2) 69 subq $40, %rsp 70 /* mov %rdx, %rdx */ 71 mov %rsi, %rcx 72 call *%rdi 73 addq $40, %rsp 74 ret 75 76ENTRY(efi_call3) 77 subq $40, %rsp 78 mov %rcx, %r8 79 /* mov %rdx, %rdx */ 80 mov %rsi, %rcx 81 call *%rdi 82 addq $40, %rsp 83 ret 84 85ENTRY(efi_call4) 86 subq $40, %rsp 87 mov %r8, %r9 88 mov %rcx, %r8 89 /* mov %rdx, %rdx */ 90 mov %rsi, %rcx 91 call *%rdi 92 addq $40, %rsp 93 ret 94 95ENTRY(efi_call5) 96 subq $40, %rsp 97 mov %r9, 32(%rsp) 98 mov %r8, %r9 99 mov %rcx, %r8 100 /* mov %rdx, %rdx */ 101 mov %rsi, %rcx 102 call *%rdi 103 addq $40, %rsp 104 ret 105 106ENTRY(efi_call6) 107 subq $56, %rsp 108 mov 56+8(%rsp), %rax 109 mov %rax, 40(%rsp) 110 mov %r9, 32(%rsp) 111 mov %r8, %r9 112 mov %rcx, %r8 113 /* mov %rdx, %rdx */ 114 mov %rsi, %rcx 115 call *%rdi 116 addq $56, %rsp 117 ret 118 119ENTRY(efi_call7) 120 subq $56, %rsp 121 mov 56+16(%rsp), %rax 122 mov %rax, 48(%rsp) 123 mov 56+8(%rsp), %rax 124 mov %rax, 40(%rsp) 125 mov %r9, 32(%rsp) 126 mov %r8, %r9 127 mov %rcx, %r8 128 /* mov %rdx, %rdx */ 129 mov %rsi, %rcx 130 call *%rdi 131 addq $56, %rsp 132 ret 133 134ENTRY(efi_call8) 135 subq $72, %rsp 136 mov 72+24(%rsp), %rax 137 mov %rax, 56(%rsp) 138 mov 72+16(%rsp), %rax 139 mov %rax, 48(%rsp) 140 mov 72+8(%rsp), %rax 141 mov %rax, 40(%rsp) 142 mov %r9, 32(%rsp) 143 mov %r8, %r9 144 mov %rcx, %r8 145 /* mov %rdx, %rdx */ 146 mov %rsi, %rcx 147 call *%rdi 148 addq $72, %rsp 149 ret 150 151ENTRY(efi_call9) 152 subq $72, %rsp 153 mov 72+32(%rsp), %rax 154 mov %rax, 64(%rsp) 155 mov 72+24(%rsp), %rax 156 mov %rax, 56(%rsp) 157 mov 72+16(%rsp), %rax 158 mov %rax, 48(%rsp) 159 mov 72+8(%rsp), %rax 160 mov %rax, 40(%rsp) 161 mov %r9, 32(%rsp) 162 mov %r8, %r9 163 mov %rcx, %r8 164 /* mov %rdx, %rdx */ 165 mov %rsi, %rcx 166 call *%rdi 167 addq $72, %rsp 168 ret 169 170ENTRY(efi_call10) 171 subq $88, %rsp 172 mov 88+40(%rsp), %rax 173 mov %rax, 72(%rsp) 174 mov 88+32(%rsp), %rax 175 mov %rax, 64(%rsp) 176 mov 88+24(%rsp), %rax 177 mov %rax, 56(%rsp) 178 mov 88+16(%rsp), %rax 179 mov %rax, 48(%rsp) 180 mov 88+8(%rsp), %rax 181 mov %rax, 40(%rsp) 182 mov %r9, 32(%rsp) 183 mov %r8, %r9 184 mov %rcx, %r8 185 /* mov %rdx, %rdx */ 186 mov %rsi, %rcx 187 call *%rdi 188 addq $88, %rsp 189 ret 190 191#endif 192