2 * From Coreboot file device/oprom/realmode/x86.c
4 * Copyright (C) 2007 Advanced Micro Devices, Inc.
5 * Copyright (C) 2009-2010 coresystems GmbH
7 * SPDX-License-Identifier: GPL-2.0
10 #include <bios_emul.h>
12 #include <linux/linkage.h>
13 #include <asm/cache.h>
14 #include <asm/processor.h>
15 #include <asm/i8259.h>
20 /* Interrupt handlers for each interrupt the ROM can call */
21 static int (*int_handler[256])(void);
23 /* to have a common register file for interrupt handlers */
24 X86EMU_sysEnv _X86EMU_env;
26 asmlinkage void (*realmode_call)(u32 addr, u32 eax, u32 ebx, u32 ecx, u32 edx,
29 asmlinkage void (*realmode_interrupt)(u32 intno, u32 eax, u32 ebx, u32 ecx,
30 u32 edx, u32 esi, u32 edi);
32 static void setup_realmode_code(void)
34 memcpy((void *)REALMODE_BASE, &asm_realmode_code,
35 asm_realmode_code_size);
37 /* Ensure the global pointers are relocated properly. */
38 realmode_call = PTR_TO_REAL_MODE(asm_realmode_call);
39 realmode_interrupt = PTR_TO_REAL_MODE(__realmode_interrupt);
41 debug("Real mode stub @%x: %d bytes\n", REALMODE_BASE,
42 asm_realmode_code_size);
45 static void setup_rombios(void)
47 const char date[] = "06/11/99";
48 memcpy((void *)0xffff5, &date, 8);
50 const char ident[] = "PCI_ISA";
51 memcpy((void *)0xfffd9, &ident, 7);
53 /* system model: IBM-AT */
54 writeb(0xfc, 0xffffe);
57 static int int_exception_handler(void)
59 /* compatibility shim */
60 struct eregs reg_info = {
69 .vector = M.x86.intno,
73 .eflags = M.x86.R_EFLG
75 struct eregs *regs = ®_info;
77 debug("Oops, exception %d while executing option rom\n", regs->vector);
83 static int int_unknown_handler(void)
85 debug("Unsupported software interrupt #0x%x eax 0x%x\n",
86 M.x86.intno, M.x86.R_EAX);
91 /* setup interrupt handlers for mainboard */
92 void bios_set_interrupt_handler(int intnum, int (*int_func)(void))
94 int_handler[intnum] = int_func;
97 static void setup_interrupt_handlers(void)
102 * The first 16 int_handler functions are not BIOS services,
103 * but the CPU-generated exceptions ("hardware interrupts")
105 for (i = 0; i < 0x10; i++)
106 int_handler[i] = &int_exception_handler;
108 /* Mark all other int_handler calls as unknown first */
109 for (i = 0x10; i < 0x100; i++) {
110 /* Skip if bios_set_interrupt_handler() isn't called first */
115 * Now set the default functions that are actually needed
116 * to initialize the option roms. The board may override
117 * these with bios_set_interrupt_handler()
121 int_handler[0x10] = &int10_handler;
124 int_handler[0x12] = &int12_handler;
127 int_handler[0x16] = &int16_handler;
130 int_handler[0x1a] = &int1a_handler;
133 int_handler[i] = &int_unknown_handler;
139 static void write_idt_stub(void *target, u8 intnum)
141 unsigned char *codeptr;
143 codeptr = (unsigned char *)target;
144 memcpy(codeptr, &__idt_handler, __idt_handler_size);
145 codeptr[3] = intnum; /* modify int# in the code stub. */
148 static void setup_realmode_idt(void)
150 struct realmode_idt *idts = NULL;
154 * Copy IDT stub code for each interrupt. This might seem wasteful
155 * but it is really simple
157 for (i = 0; i < 256; i++) {
159 idts[i].offset = 0x1000 + (i * __idt_handler_size);
160 write_idt_stub((void *)((u32)idts[i].offset), i);
164 * Many option ROMs use the hard coded interrupt entry points in the
165 * system bios. So install them at the known locations.
168 /* int42 is the relocated int10 */
169 write_idt_stub((void *)0xff065, 0x42);
170 /* BIOS Int 11 Handler F000:F84D */
171 write_idt_stub((void *)0xff84d, 0x11);
172 /* BIOS Int 12 Handler F000:F841 */
173 write_idt_stub((void *)0xff841, 0x12);
174 /* BIOS Int 13 Handler F000:EC59 */
175 write_idt_stub((void *)0xfec59, 0x13);
176 /* BIOS Int 14 Handler F000:E739 */
177 write_idt_stub((void *)0xfe739, 0x14);
178 /* BIOS Int 15 Handler F000:F859 */
179 write_idt_stub((void *)0xff859, 0x15);
180 /* BIOS Int 16 Handler F000:E82E */
181 write_idt_stub((void *)0xfe82e, 0x16);
182 /* BIOS Int 17 Handler F000:EFD2 */
183 write_idt_stub((void *)0xfefd2, 0x17);
184 /* ROM BIOS Int 1A Handler F000:FE6E */
185 write_idt_stub((void *)0xffe6e, 0x1a);
188 static u8 vbe_get_mode_info(struct vbe_mode_info *mi)
194 debug("VBE: Getting information about VESA mode %04x\n",
196 buffer = PTR_TO_REAL_MODE(asm_realmode_buffer);
197 buffer_seg = (((unsigned long)buffer) >> 4) & 0xff00;
198 buffer_adr = ((unsigned long)buffer) & 0xffff;
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));
208 static u8 vbe_set_mode(struct vbe_mode_info *mi)
210 int video_mode = mi->video_mode;
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);
223 static void vbe_set_graphics(int vesa_mode, struct vbe_mode_info *mode_info)
225 unsigned char *framebuffer;
227 mode_info->video_mode = (1 << 14) | vesa_mode;
228 vbe_get_mode_info(mode_info);
230 framebuffer = (unsigned char *)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);
237 debug("VBE: Mode does not support linear framebuffer\n");
241 mode_info->video_mode &= 0x3ff;
242 vbe_set_mode(mode_info);
245 void bios_run_on_x86(pci_dev_t pcidev, unsigned long addr, int vesa_mode,
246 struct vbe_mode_info *mode_info)
250 num_dev = PCI_BUS(pcidev) << 8 | PCI_DEV(pcidev) << 3 |
253 /* Needed to avoid exceptions in some ROMs */
256 /* Set up some legacy information in the F segment */
259 /* Set up C interrupt handlers */
260 setup_interrupt_handlers();
262 /* Set up real-mode IDT */
263 setup_realmode_idt();
265 /* Make sure the code is placed. */
266 setup_realmode_code();
268 debug("Calling Option ROM at %lx, pci device %#x...", addr, num_dev);
270 /* Option ROM entry point is at OPROM start + 3 */
271 realmode_call(addr + 0x0003, num_dev, 0xffff, 0x0000, 0xffff, 0x0,
276 vbe_set_graphics(vesa_mode, mode_info);
279 asmlinkage int interrupt_handler(u32 intnumber, u32 gsfs, u32 dses,
280 u32 edi, u32 esi, u32 ebp, u32 esp,
281 u32 ebx, u32 edx, u32 ecx, u32 eax,
282 u32 cs_ip, u16 stackflags)
293 #ifdef CONFIG_REALMODE_DEBUG
294 debug("oprom: INT# 0x%x\n", intnumber);
295 debug("oprom: eax: %08x ebx: %08x ecx: %08x edx: %08x\n",
297 debug("oprom: ebp: %08x esp: %08x edi: %08x esi: %08x\n",
299 debug("oprom: ip: %04x cs: %04x flags: %08x\n",
301 debug("oprom: stackflags = %04x\n", stackflags);
305 * Fetch arguments from the stack and put them to a place
306 * suitable for the interrupt handlers
316 M.x86.intno = intnumber;
319 M.x86.R_EFLG = flags;
321 /* Call the interrupt handler for this interrupt number */
322 ret = int_handler[intnumber]();
325 * This code is quite strange...
327 * Put registers back on the stack. The assembler code will pop them
328 * later. We force (volatile!) changing the values of the parameters
329 * of this function. We know that they stay alive on the stack after
330 * we leave this function.
332 *(volatile u32 *)&eax = M.x86.R_EAX;
333 *(volatile u32 *)&ecx = M.x86.R_ECX;
334 *(volatile u32 *)&edx = M.x86.R_EDX;
335 *(volatile u32 *)&ebx = M.x86.R_EBX;
336 *(volatile u32 *)&esi = M.x86.R_ESI;
337 *(volatile u32 *)&edi = M.x86.R_EDI;
338 flags = M.x86.R_EFLG;
340 /* Pass success or error back to our caller via the CARRY flag */
342 flags &= ~1; /* no error: clear carry */
344 debug("int%02x call returned error\n", intnumber);
345 flags |= 1; /* error: set carry */
347 *(volatile u16 *)&stackflags = flags;