1 /* 2 * From Coreboot file device/oprom/realmode/x86.c 3 * 4 * Copyright (C) 2007 Advanced Micro Devices, Inc. 5 * Copyright (C) 2009-2010 coresystems GmbH 6 * 7 * SPDX-License-Identifier: GPL-2.0 8 */ 9 #include <common.h> 10 #include <bios_emul.h> 11 #include <vbe.h> 12 #include <asm/cache.h> 13 #include <asm/processor.h> 14 #include <asm/i8259.h> 15 #include <asm/io.h> 16 #include <asm/post.h> 17 #include "bios.h" 18 19 /* Interrupt handlers for each interrupt the ROM can call */ 20 static int (*int_handler[256])(void); 21 22 /* to have a common register file for interrupt handlers */ 23 X86EMU_sysEnv _X86EMU_env; 24 25 asmlinkage void (*realmode_call)(u32 addr, u32 eax, u32 ebx, u32 ecx, u32 edx, 26 u32 esi, u32 edi); 27 28 asmlinkage void (*realmode_interrupt)(u32 intno, u32 eax, u32 ebx, u32 ecx, 29 u32 edx, u32 esi, u32 edi); 30 31 static void setup_realmode_code(void) 32 { 33 memcpy((void *)REALMODE_BASE, &asm_realmode_code, 34 asm_realmode_code_size); 35 36 /* Ensure the global pointers are relocated properly. */ 37 realmode_call = PTR_TO_REAL_MODE(asm_realmode_call); 38 realmode_interrupt = PTR_TO_REAL_MODE(__realmode_interrupt); 39 40 debug("Real mode stub @%x: %d bytes\n", REALMODE_BASE, 41 asm_realmode_code_size); 42 } 43 44 static void setup_rombios(void) 45 { 46 const char date[] = "06/11/99"; 47 memcpy((void *)0xffff5, &date, 8); 48 49 const char ident[] = "PCI_ISA"; 50 memcpy((void *)0xfffd9, &ident, 7); 51 52 /* system model: IBM-AT */ 53 writeb(0xfc, 0xffffe); 54 } 55 56 static int int_exception_handler(void) 57 { 58 /* compatibility shim */ 59 struct eregs reg_info = { 60 .eax = M.x86.R_EAX, 61 .ecx = M.x86.R_ECX, 62 .edx = M.x86.R_EDX, 63 .ebx = M.x86.R_EBX, 64 .esp = M.x86.R_ESP, 65 .ebp = M.x86.R_EBP, 66 .esi = M.x86.R_ESI, 67 .edi = M.x86.R_EDI, 68 .vector = M.x86.intno, 69 .error_code = 0, 70 .eip = M.x86.R_EIP, 71 .cs = M.x86.R_CS, 72 .eflags = M.x86.R_EFLG 73 }; 74 struct eregs *regs = ®_info; 75 76 debug("Oops, exception %d while executing option rom\n", regs->vector); 77 cpu_hlt(); 78 79 return 0; 80 } 81 82 static int int_unknown_handler(void) 83 { 84 debug("Unsupported software interrupt #0x%x eax 0x%x\n", 85 M.x86.intno, M.x86.R_EAX); 86 87 return -1; 88 } 89 90 /* setup interrupt handlers for mainboard */ 91 void bios_set_interrupt_handler(int intnum, int (*int_func)(void)) 92 { 93 int_handler[intnum] = int_func; 94 } 95 96 static void setup_interrupt_handlers(void) 97 { 98 int i; 99 100 /* 101 * The first 16 int_handler functions are not BIOS services, 102 * but the CPU-generated exceptions ("hardware interrupts") 103 */ 104 for (i = 0; i < 0x10; i++) 105 int_handler[i] = &int_exception_handler; 106 107 /* Mark all other int_handler calls as unknown first */ 108 for (i = 0x10; i < 0x100; i++) { 109 /* Skip if bios_set_interrupt_handler() isn't called first */ 110 if (int_handler[i]) 111 continue; 112 113 /* 114 * Now set the default functions that are actually needed 115 * to initialize the option roms. The board may override 116 * these with bios_set_interrupt_handler() 117 */ 118 switch (i) { 119 case 0x10: 120 int_handler[0x10] = &int10_handler; 121 break; 122 case 0x12: 123 int_handler[0x12] = &int12_handler; 124 break; 125 case 0x16: 126 int_handler[0x16] = &int16_handler; 127 break; 128 case 0x1a: 129 int_handler[0x1a] = &int1a_handler; 130 break; 131 default: 132 int_handler[i] = &int_unknown_handler; 133 break; 134 } 135 } 136 } 137 138 static void write_idt_stub(void *target, u8 intnum) 139 { 140 unsigned char *codeptr; 141 142 codeptr = (unsigned char *)target; 143 memcpy(codeptr, &__idt_handler, __idt_handler_size); 144 codeptr[3] = intnum; /* modify int# in the code stub. */ 145 } 146 147 static void setup_realmode_idt(void) 148 { 149 struct realmode_idt *idts = NULL; 150 int i; 151 152 /* 153 * Copy IDT stub code for each interrupt. This might seem wasteful 154 * but it is really simple 155 */ 156 for (i = 0; i < 256; i++) { 157 idts[i].cs = 0; 158 idts[i].offset = 0x1000 + (i * __idt_handler_size); 159 write_idt_stub((void *)((u32)idts[i].offset), i); 160 } 161 162 /* 163 * Many option ROMs use the hard coded interrupt entry points in the 164 * system bios. So install them at the known locations. 165 */ 166 167 /* int42 is the relocated int10 */ 168 write_idt_stub((void *)0xff065, 0x42); 169 /* BIOS Int 11 Handler F000:F84D */ 170 write_idt_stub((void *)0xff84d, 0x11); 171 /* BIOS Int 12 Handler F000:F841 */ 172 write_idt_stub((void *)0xff841, 0x12); 173 /* BIOS Int 13 Handler F000:EC59 */ 174 write_idt_stub((void *)0xfec59, 0x13); 175 /* BIOS Int 14 Handler F000:E739 */ 176 write_idt_stub((void *)0xfe739, 0x14); 177 /* BIOS Int 15 Handler F000:F859 */ 178 write_idt_stub((void *)0xff859, 0x15); 179 /* BIOS Int 16 Handler F000:E82E */ 180 write_idt_stub((void *)0xfe82e, 0x16); 181 /* BIOS Int 17 Handler F000:EFD2 */ 182 write_idt_stub((void *)0xfefd2, 0x17); 183 /* ROM BIOS Int 1A Handler F000:FE6E */ 184 write_idt_stub((void *)0xffe6e, 0x1a); 185 } 186 187 static u8 vbe_get_mode_info(struct vbe_mode_info *mi) 188 { 189 u16 buffer_seg; 190 u16 buffer_adr; 191 char *buffer; 192 193 debug("VBE: Getting information about VESA mode %04x\n", 194 mi->video_mode); 195 buffer = PTR_TO_REAL_MODE(asm_realmode_buffer); 196 buffer_seg = (((unsigned long)buffer) >> 4) & 0xff00; 197 buffer_adr = ((unsigned long)buffer) & 0xffff; 198 199 realmode_interrupt(0x10, VESA_GET_MODE_INFO, 0x0000, mi->video_mode, 200 0x0000, buffer_seg, buffer_adr); 201 memcpy(mi->mode_info_block, buffer, sizeof(struct vbe_mode_info)); 202 mi->valid = true; 203 204 return 0; 205 } 206 207 static u8 vbe_set_mode(struct vbe_mode_info *mi) 208 { 209 debug("VBE: Setting VESA mode %#04x\n", mi->video_mode); 210 /* request linear framebuffer mode */ 211 mi->video_mode |= (1 << 14); 212 /* request clearing of framebuffer */ 213 mi->video_mode &= ~(1 << 15); 214 realmode_interrupt(0x10, VESA_SET_MODE, mi->video_mode, 215 0x0000, 0x0000, 0x0000, 0x0000); 216 217 return 0; 218 } 219 220 static void vbe_set_graphics(int vesa_mode, struct vbe_mode_info *mode_info) 221 { 222 unsigned char *framebuffer; 223 224 mode_info->video_mode = (1 << 14) | vesa_mode; 225 vbe_get_mode_info(mode_info); 226 227 framebuffer = (unsigned char *)mode_info->vesa.phys_base_ptr; 228 debug("VBE: resolution: %dx%d@%d\n", 229 le16_to_cpu(mode_info->vesa.x_resolution), 230 le16_to_cpu(mode_info->vesa.y_resolution), 231 mode_info->vesa.bits_per_pixel); 232 debug("VBE: framebuffer: %p\n", framebuffer); 233 if (!framebuffer) { 234 debug("VBE: Mode does not support linear framebuffer\n"); 235 return; 236 } 237 238 vbe_set_mode(mode_info); 239 } 240 241 void bios_run_on_x86(pci_dev_t pcidev, unsigned long addr, int vesa_mode, 242 struct vbe_mode_info *mode_info) 243 { 244 u32 num_dev; 245 246 num_dev = PCI_BUS(pcidev) << 8 | PCI_DEV(pcidev) << 3 | 247 PCI_FUNC(pcidev); 248 249 /* Needed to avoid exceptions in some ROMs */ 250 interrupt_init(); 251 252 /* Set up some legacy information in the F segment */ 253 setup_rombios(); 254 255 /* Set up C interrupt handlers */ 256 setup_interrupt_handlers(); 257 258 /* Set up real-mode IDT */ 259 setup_realmode_idt(); 260 261 /* Make sure the code is placed. */ 262 setup_realmode_code(); 263 264 disable_caches(); 265 debug("Calling Option ROM at %lx, pci device %#x...", addr, num_dev); 266 267 /* Option ROM entry point is at OPROM start + 3 */ 268 realmode_call(addr + 0x0003, num_dev, 0xffff, 0x0000, 0xffff, 0x0, 269 0x0); 270 debug("done\n"); 271 272 if (vesa_mode != -1) 273 vbe_set_graphics(vesa_mode, mode_info); 274 } 275 276 asmlinkage int interrupt_handler(u32 intnumber, u32 gsfs, u32 dses, 277 u32 edi, u32 esi, u32 ebp, u32 esp, 278 u32 ebx, u32 edx, u32 ecx, u32 eax, 279 u32 cs_ip, u16 stackflags) 280 { 281 u32 ip; 282 u32 cs; 283 u32 flags; 284 int ret = 0; 285 286 ip = cs_ip & 0xffff; 287 cs = cs_ip >> 16; 288 flags = stackflags; 289 290 #ifdef CONFIG_REALMODE_DEBUG 291 debug("oprom: INT# 0x%x\n", intnumber); 292 debug("oprom: eax: %08x ebx: %08x ecx: %08x edx: %08x\n", 293 eax, ebx, ecx, edx); 294 debug("oprom: ebp: %08x esp: %08x edi: %08x esi: %08x\n", 295 ebp, esp, edi, esi); 296 debug("oprom: ip: %04x cs: %04x flags: %08x\n", 297 ip, cs, flags); 298 debug("oprom: stackflags = %04x\n", stackflags); 299 #endif 300 301 /* 302 * Fetch arguments from the stack and put them to a place 303 * suitable for the interrupt handlers 304 */ 305 M.x86.R_EAX = eax; 306 M.x86.R_ECX = ecx; 307 M.x86.R_EDX = edx; 308 M.x86.R_EBX = ebx; 309 M.x86.R_ESP = esp; 310 M.x86.R_EBP = ebp; 311 M.x86.R_ESI = esi; 312 M.x86.R_EDI = edi; 313 M.x86.intno = intnumber; 314 M.x86.R_EIP = ip; 315 M.x86.R_CS = cs; 316 M.x86.R_EFLG = flags; 317 318 /* Call the interrupt handler for this interrupt number */ 319 ret = int_handler[intnumber](); 320 321 /* 322 * This code is quite strange... 323 * 324 * Put registers back on the stack. The assembler code will pop them 325 * later. We force (volatile!) changing the values of the parameters 326 * of this function. We know that they stay alive on the stack after 327 * we leave this function. 328 */ 329 *(volatile u32 *)&eax = M.x86.R_EAX; 330 *(volatile u32 *)&ecx = M.x86.R_ECX; 331 *(volatile u32 *)&edx = M.x86.R_EDX; 332 *(volatile u32 *)&ebx = M.x86.R_EBX; 333 *(volatile u32 *)&esi = M.x86.R_ESI; 334 *(volatile u32 *)&edi = M.x86.R_EDI; 335 flags = M.x86.R_EFLG; 336 337 /* Pass success or error back to our caller via the CARRY flag */ 338 if (ret) { 339 flags &= ~1; /* no error: clear carry */ 340 } else { 341 debug("int%02x call returned error\n", intnumber); 342 flags |= 1; /* error: set carry */ 343 } 344 *(volatile u16 *)&stackflags = flags; 345 346 return ret; 347 } 348