1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * From Coreboot file device/oprom/realmode/x86.c 4 * 5 * Copyright (C) 2007 Advanced Micro Devices, Inc. 6 * Copyright (C) 2009-2010 coresystems GmbH 7 */ 8 #include <common.h> 9 #include <bios_emul.h> 10 #include <vbe.h> 11 #include <linux/linkage.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 *)((ulong)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 #ifdef CONFIG_FRAMEBUFFER_SET_VESA_MODE 188 static u8 vbe_get_mode_info(struct vbe_mode_info *mi) 189 { 190 u16 buffer_seg; 191 u16 buffer_adr; 192 char *buffer; 193 194 debug("VBE: Getting information about VESA mode %04x\n", 195 mi->video_mode); 196 buffer = PTR_TO_REAL_MODE(asm_realmode_buffer); 197 buffer_seg = (((unsigned long)buffer) >> 4) & 0xff00; 198 buffer_adr = ((unsigned long)buffer) & 0xffff; 199 200 realmode_interrupt(0x10, VESA_GET_MODE_INFO, 0x0000, mi->video_mode, 201 0x0000, buffer_seg, buffer_adr); 202 memcpy(mi->mode_info_block, buffer, sizeof(struct vbe_mode_info)); 203 mi->valid = true; 204 205 return 0; 206 } 207 208 static u8 vbe_set_mode(struct vbe_mode_info *mi) 209 { 210 int video_mode = mi->video_mode; 211 212 debug("VBE: Setting VESA mode %#04x\n", video_mode); 213 /* request linear framebuffer mode */ 214 video_mode |= (1 << 14); 215 /* don't clear the framebuffer, we do that later */ 216 video_mode |= (1 << 15); 217 realmode_interrupt(0x10, VESA_SET_MODE, video_mode, 218 0x0000, 0x0000, 0x0000, 0x0000); 219 220 return 0; 221 } 222 223 static void vbe_set_graphics(int vesa_mode, struct vbe_mode_info *mode_info) 224 { 225 unsigned char *framebuffer; 226 227 mode_info->video_mode = (1 << 14) | vesa_mode; 228 vbe_get_mode_info(mode_info); 229 230 framebuffer = (unsigned char *)(ulong)mode_info->vesa.phys_base_ptr; 231 debug("VBE: resolution: %dx%d@%d\n", 232 le16_to_cpu(mode_info->vesa.x_resolution), 233 le16_to_cpu(mode_info->vesa.y_resolution), 234 mode_info->vesa.bits_per_pixel); 235 debug("VBE: framebuffer: %p\n", framebuffer); 236 if (!framebuffer) { 237 debug("VBE: Mode does not support linear framebuffer\n"); 238 return; 239 } 240 241 mode_info->video_mode &= 0x3ff; 242 vbe_set_mode(mode_info); 243 } 244 #endif /* CONFIG_FRAMEBUFFER_SET_VESA_MODE */ 245 246 void bios_run_on_x86(struct udevice *dev, unsigned long addr, int vesa_mode, 247 struct vbe_mode_info *mode_info) 248 { 249 pci_dev_t pcidev = dm_pci_get_bdf(dev); 250 u32 num_dev; 251 252 num_dev = PCI_BUS(pcidev) << 8 | PCI_DEV(pcidev) << 3 | 253 PCI_FUNC(pcidev); 254 255 /* Needed to avoid exceptions in some ROMs */ 256 interrupt_init(); 257 258 /* Set up some legacy information in the F segment */ 259 setup_rombios(); 260 261 /* Set up C interrupt handlers */ 262 setup_interrupt_handlers(); 263 264 /* Set up real-mode IDT */ 265 setup_realmode_idt(); 266 267 /* Make sure the code is placed. */ 268 setup_realmode_code(); 269 270 debug("Calling Option ROM at %lx, pci device %#x...", addr, num_dev); 271 272 /* Option ROM entry point is at OPROM start + 3 */ 273 realmode_call(addr + 0x0003, num_dev, 0xffff, 0x0000, 0xffff, 0x0, 274 0x0); 275 debug("done\n"); 276 277 #ifdef CONFIG_FRAMEBUFFER_SET_VESA_MODE 278 if (vesa_mode != -1) 279 vbe_set_graphics(vesa_mode, mode_info); 280 #endif 281 } 282 283 asmlinkage int interrupt_handler(u32 intnumber, u32 gsfs, u32 dses, 284 u32 edi, u32 esi, u32 ebp, u32 esp, 285 u32 ebx, u32 edx, u32 ecx, u32 eax, 286 u32 cs_ip, u16 stackflags) 287 { 288 u32 ip; 289 u32 cs; 290 u32 flags; 291 int ret = 0; 292 293 ip = cs_ip & 0xffff; 294 cs = cs_ip >> 16; 295 flags = stackflags; 296 297 #ifdef CONFIG_REALMODE_DEBUG 298 debug("oprom: INT# 0x%x\n", intnumber); 299 debug("oprom: eax: %08x ebx: %08x ecx: %08x edx: %08x\n", 300 eax, ebx, ecx, edx); 301 debug("oprom: ebp: %08x esp: %08x edi: %08x esi: %08x\n", 302 ebp, esp, edi, esi); 303 debug("oprom: ip: %04x cs: %04x flags: %08x\n", 304 ip, cs, flags); 305 debug("oprom: stackflags = %04x\n", stackflags); 306 #endif 307 308 /* 309 * Fetch arguments from the stack and put them to a place 310 * suitable for the interrupt handlers 311 */ 312 M.x86.R_EAX = eax; 313 M.x86.R_ECX = ecx; 314 M.x86.R_EDX = edx; 315 M.x86.R_EBX = ebx; 316 M.x86.R_ESP = esp; 317 M.x86.R_EBP = ebp; 318 M.x86.R_ESI = esi; 319 M.x86.R_EDI = edi; 320 M.x86.intno = intnumber; 321 M.x86.R_EIP = ip; 322 M.x86.R_CS = cs; 323 M.x86.R_EFLG = flags; 324 325 /* Call the interrupt handler for this interrupt number */ 326 ret = int_handler[intnumber](); 327 328 /* 329 * This code is quite strange... 330 * 331 * Put registers back on the stack. The assembler code will pop them 332 * later. We force (volatile!) changing the values of the parameters 333 * of this function. We know that they stay alive on the stack after 334 * we leave this function. 335 */ 336 *(volatile u32 *)&eax = M.x86.R_EAX; 337 *(volatile u32 *)&ecx = M.x86.R_ECX; 338 *(volatile u32 *)&edx = M.x86.R_EDX; 339 *(volatile u32 *)&ebx = M.x86.R_EBX; 340 *(volatile u32 *)&esi = M.x86.R_ESI; 341 *(volatile u32 *)&edi = M.x86.R_EDI; 342 flags = M.x86.R_EFLG; 343 344 /* Pass success or error back to our caller via the CARRY flag */ 345 if (ret) { 346 flags &= ~1; /* no error: clear carry */ 347 } else { 348 debug("int%02x call returned error\n", intnumber); 349 flags |= 1; /* error: set carry */ 350 } 351 *(volatile u16 *)&stackflags = flags; 352 353 return ret; 354 } 355