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
setup_realmode_code(void)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
setup_rombios(void)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
int_exception_handler(void)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
int_unknown_handler(void)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 */
bios_set_interrupt_handler(int intnum,int (* int_func)(void))91 void bios_set_interrupt_handler(int intnum, int (*int_func)(void))
92 {
93 int_handler[intnum] = int_func;
94 }
95
setup_interrupt_handlers(void)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
write_idt_stub(void * target,u8 intnum)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
setup_realmode_idt(void)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
vbe_get_mode_info(struct vbe_mode_info * mi)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
vbe_set_mode(struct vbe_mode_info * mi)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
vbe_set_graphics(int vesa_mode,struct vbe_mode_info * mode_info)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
bios_run_on_x86(struct udevice * dev,unsigned long addr,int vesa_mode,struct vbe_mode_info * mode_info)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
interrupt_handler(u32 intnumber,u32 gsfs,u32 dses,u32 edi,u32 esi,u32 ebp,u32 esp,u32 ebx,u32 edx,u32 ecx,u32 eax,u32 cs_ip,u16 stackflags)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