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 <compiler.h>
10 #include <bios_emul.h>
11 #include <irq_func.h>
12 #include <log.h>
13 #include <vbe.h>
14 #include <linux/linkage.h>
15 #include <asm/cache.h>
16 #include <asm/processor.h>
17 #include <asm/i8259.h>
18 #include <asm/io.h>
19 #include <asm/post.h>
20 #include "bios.h"
21
22 /* Interrupt handlers for each interrupt the ROM can call */
23 static int (*int_handler[256])(void);
24
25 /* to have a common register file for interrupt handlers */
26 #ifndef CONFIG_BIOSEMU
27 X86EMU_sysEnv _X86EMU_env;
28 #endif
29
30 asmlinkage void (*realmode_call)(u32 addr, u32 eax, u32 ebx, u32 ecx, u32 edx,
31 u32 esi, u32 edi);
32
33 asmlinkage void (*realmode_interrupt)(u32 intno, u32 eax, u32 ebx, u32 ecx,
34 u32 edx, u32 esi, u32 edi);
35
setup_realmode_code(void)36 static void setup_realmode_code(void)
37 {
38 memcpy((void *)REALMODE_BASE, &asm_realmode_code,
39 asm_realmode_code_size);
40
41 /* Ensure the global pointers are relocated properly. */
42 realmode_call = PTR_TO_REAL_MODE(asm_realmode_call);
43 realmode_interrupt = PTR_TO_REAL_MODE(__realmode_interrupt);
44
45 debug("Real mode stub @%x: %d bytes\n", REALMODE_BASE,
46 asm_realmode_code_size);
47 }
48
setup_rombios(void)49 static void setup_rombios(void)
50 {
51 const char date[] = "06/11/99";
52 memcpy((void *)0xffff5, &date, 8);
53
54 const char ident[] = "PCI_ISA";
55 memcpy((void *)0xfffd9, &ident, 7);
56
57 /* system model: IBM-AT */
58 writeb(0xfc, 0xffffe);
59 }
60
int_exception_handler(void)61 static int int_exception_handler(void)
62 {
63 /* compatibility shim */
64 struct eregs reg_info = {
65 .eax = M.x86.R_EAX,
66 .ecx = M.x86.R_ECX,
67 .edx = M.x86.R_EDX,
68 .ebx = M.x86.R_EBX,
69 .esp = M.x86.R_ESP,
70 .ebp = M.x86.R_EBP,
71 .esi = M.x86.R_ESI,
72 .edi = M.x86.R_EDI,
73 .vector = M.x86.intno,
74 .error_code = 0,
75 .eip = M.x86.R_EIP,
76 .cs = M.x86.R_CS,
77 .eflags = M.x86.R_EFLG
78 };
79 struct eregs *regs = ®_info;
80
81 debug("Oops, exception %d while executing option rom\n", regs->vector);
82 cpu_hlt();
83
84 return 0;
85 }
86
int_unknown_handler(void)87 static int int_unknown_handler(void)
88 {
89 debug("Unsupported software interrupt #0x%x eax 0x%x\n",
90 M.x86.intno, M.x86.R_EAX);
91
92 return -1;
93 }
94
95 /* setup interrupt handlers for mainboard */
bios_set_interrupt_handler(int intnum,int (* int_func)(void))96 void bios_set_interrupt_handler(int intnum, int (*int_func)(void))
97 {
98 int_handler[intnum] = int_func;
99 }
100
setup_interrupt_handlers(void)101 static void setup_interrupt_handlers(void)
102 {
103 int i;
104
105 /*
106 * The first 16 int_handler functions are not BIOS services,
107 * but the CPU-generated exceptions ("hardware interrupts")
108 */
109 for (i = 0; i < 0x10; i++)
110 int_handler[i] = &int_exception_handler;
111
112 /* Mark all other int_handler calls as unknown first */
113 for (i = 0x10; i < 0x100; i++) {
114 /* Skip if bios_set_interrupt_handler() isn't called first */
115 if (int_handler[i])
116 continue;
117
118 /*
119 * Now set the default functions that are actually needed
120 * to initialize the option roms. The board may override
121 * these with bios_set_interrupt_handler()
122 */
123 switch (i) {
124 case 0x10:
125 int_handler[0x10] = &int10_handler;
126 break;
127 case 0x12:
128 int_handler[0x12] = &int12_handler;
129 break;
130 case 0x16:
131 int_handler[0x16] = &int16_handler;
132 break;
133 case 0x1a:
134 int_handler[0x1a] = &int1a_handler;
135 break;
136 default:
137 int_handler[i] = &int_unknown_handler;
138 break;
139 }
140 }
141 }
142
write_idt_stub(void * target,u8 intnum)143 static void write_idt_stub(void *target, u8 intnum)
144 {
145 unsigned char *codeptr;
146
147 codeptr = (unsigned char *)target;
148 memcpy(codeptr, &__idt_handler, __idt_handler_size);
149 codeptr[3] = intnum; /* modify int# in the code stub. */
150 }
151
setup_realmode_idt(void)152 static void setup_realmode_idt(void)
153 {
154 struct realmode_idt *idts = NULL;
155 int i;
156
157 /*
158 * Copy IDT stub code for each interrupt. This might seem wasteful
159 * but it is really simple
160 */
161 for (i = 0; i < 256; i++) {
162 idts[i].cs = 0;
163 idts[i].offset = 0x1000 + (i * __idt_handler_size);
164 write_idt_stub((void *)((ulong)idts[i].offset), i);
165 }
166
167 /*
168 * Many option ROMs use the hard coded interrupt entry points in the
169 * system bios. So install them at the known locations.
170 */
171
172 /* int42 is the relocated int10 */
173 write_idt_stub((void *)0xff065, 0x42);
174 /* BIOS Int 11 Handler F000:F84D */
175 write_idt_stub((void *)0xff84d, 0x11);
176 /* BIOS Int 12 Handler F000:F841 */
177 write_idt_stub((void *)0xff841, 0x12);
178 /* BIOS Int 13 Handler F000:EC59 */
179 write_idt_stub((void *)0xfec59, 0x13);
180 /* BIOS Int 14 Handler F000:E739 */
181 write_idt_stub((void *)0xfe739, 0x14);
182 /* BIOS Int 15 Handler F000:F859 */
183 write_idt_stub((void *)0xff859, 0x15);
184 /* BIOS Int 16 Handler F000:E82E */
185 write_idt_stub((void *)0xfe82e, 0x16);
186 /* BIOS Int 17 Handler F000:EFD2 */
187 write_idt_stub((void *)0xfefd2, 0x17);
188 /* ROM BIOS Int 1A Handler F000:FE6E */
189 write_idt_stub((void *)0xffe6e, 0x1a);
190 }
191
192 #ifdef CONFIG_FRAMEBUFFER_SET_VESA_MODE
vbe_get_mode_info(struct vbe_mode_info * mi)193 static u8 vbe_get_mode_info(struct vbe_mode_info *mi)
194 {
195 u16 buffer_seg;
196 u16 buffer_adr;
197 char *buffer;
198
199 debug("VBE: Getting information about VESA mode %04x\n",
200 mi->video_mode);
201 buffer = PTR_TO_REAL_MODE(asm_realmode_buffer);
202 buffer_seg = (((unsigned long)buffer) >> 4) & 0xff00;
203 buffer_adr = ((unsigned long)buffer) & 0xffff;
204
205 realmode_interrupt(0x10, VESA_GET_MODE_INFO, 0x0000, mi->video_mode,
206 0x0000, buffer_seg, buffer_adr);
207 memcpy(mi->mode_info_block, buffer, sizeof(struct vbe_mode_info));
208 mi->valid = true;
209
210 return 0;
211 }
212
vbe_set_mode(struct vbe_mode_info * mi)213 static u8 vbe_set_mode(struct vbe_mode_info *mi)
214 {
215 int video_mode = mi->video_mode;
216
217 debug("VBE: Setting VESA mode %#04x\n", video_mode);
218 /* request linear framebuffer mode */
219 video_mode |= (1 << 14);
220 /* don't clear the framebuffer, we do that later */
221 video_mode |= (1 << 15);
222 realmode_interrupt(0x10, VESA_SET_MODE, video_mode,
223 0x0000, 0x0000, 0x0000, 0x0000);
224
225 return 0;
226 }
227
vbe_set_graphics(int vesa_mode,struct vbe_mode_info * mode_info)228 static void vbe_set_graphics(int vesa_mode, struct vbe_mode_info *mode_info)
229 {
230 unsigned char *framebuffer;
231
232 mode_info->video_mode = (1 << 14) | vesa_mode;
233 vbe_get_mode_info(mode_info);
234
235 framebuffer = (unsigned char *)(ulong)mode_info->vesa.phys_base_ptr;
236 debug("VBE: resolution: %dx%d@%d\n",
237 le16_to_cpu(mode_info->vesa.x_resolution),
238 le16_to_cpu(mode_info->vesa.y_resolution),
239 mode_info->vesa.bits_per_pixel);
240 debug("VBE: framebuffer: %p\n", framebuffer);
241 if (!framebuffer) {
242 debug("VBE: Mode does not support linear framebuffer\n");
243 return;
244 }
245
246 mode_info->video_mode &= 0x3ff;
247 vbe_set_mode(mode_info);
248 }
249 #endif /* CONFIG_FRAMEBUFFER_SET_VESA_MODE */
250
bios_run_on_x86(struct udevice * dev,unsigned long addr,int vesa_mode,struct vbe_mode_info * mode_info)251 void bios_run_on_x86(struct udevice *dev, unsigned long addr, int vesa_mode,
252 struct vbe_mode_info *mode_info)
253 {
254 pci_dev_t pcidev = dm_pci_get_bdf(dev);
255 u32 num_dev;
256
257 num_dev = PCI_BUS(pcidev) << 8 | PCI_DEV(pcidev) << 3 |
258 PCI_FUNC(pcidev);
259
260 /* Needed to avoid exceptions in some ROMs */
261 interrupt_init();
262
263 /* Set up some legacy information in the F segment */
264 setup_rombios();
265
266 /* Set up C interrupt handlers */
267 setup_interrupt_handlers();
268
269 /* Set up real-mode IDT */
270 setup_realmode_idt();
271
272 /* Make sure the code is placed. */
273 setup_realmode_code();
274
275 debug("Calling Option ROM at %lx, pci device %#x...", addr, num_dev);
276
277 /* Option ROM entry point is at OPROM start + 3 */
278 realmode_call(addr + 0x0003, num_dev, 0xffff, 0x0000, 0xffff, 0x0,
279 0x0);
280 debug("done\n");
281
282 #ifdef CONFIG_FRAMEBUFFER_SET_VESA_MODE
283 if (vesa_mode != -1)
284 vbe_set_graphics(vesa_mode, mode_info);
285 #endif
286 }
287
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)288 asmlinkage int interrupt_handler(u32 intnumber, u32 gsfs, u32 dses,
289 u32 edi, u32 esi, u32 ebp, u32 esp,
290 u32 ebx, u32 edx, u32 ecx, u32 eax,
291 u32 cs_ip, u16 stackflags)
292 {
293 u32 ip;
294 u32 cs;
295 u32 flags;
296 int ret = 0;
297
298 ip = cs_ip & 0xffff;
299 cs = cs_ip >> 16;
300 flags = stackflags;
301
302 #ifdef CONFIG_REALMODE_DEBUG
303 debug("oprom: INT# 0x%x\n", intnumber);
304 debug("oprom: eax: %08x ebx: %08x ecx: %08x edx: %08x\n",
305 eax, ebx, ecx, edx);
306 debug("oprom: ebp: %08x esp: %08x edi: %08x esi: %08x\n",
307 ebp, esp, edi, esi);
308 debug("oprom: ip: %04x cs: %04x flags: %08x\n",
309 ip, cs, flags);
310 debug("oprom: stackflags = %04x\n", stackflags);
311 #endif
312
313 /*
314 * Fetch arguments from the stack and put them to a place
315 * suitable for the interrupt handlers
316 */
317 M.x86.R_EAX = eax;
318 M.x86.R_ECX = ecx;
319 M.x86.R_EDX = edx;
320 M.x86.R_EBX = ebx;
321 M.x86.R_ESP = esp;
322 M.x86.R_EBP = ebp;
323 M.x86.R_ESI = esi;
324 M.x86.R_EDI = edi;
325 M.x86.intno = intnumber;
326 M.x86.R_EIP = ip;
327 M.x86.R_CS = cs;
328 M.x86.R_EFLG = flags;
329
330 /* Call the interrupt handler for this interrupt number */
331 ret = int_handler[intnumber]();
332
333 /*
334 * This code is quite strange...
335 *
336 * Put registers back on the stack. The assembler code will pop them
337 * later. We force (volatile!) changing the values of the parameters
338 * of this function. We know that they stay alive on the stack after
339 * we leave this function.
340 */
341 *(volatile u32 *)&eax = M.x86.R_EAX;
342 *(volatile u32 *)&ecx = M.x86.R_ECX;
343 *(volatile u32 *)&edx = M.x86.R_EDX;
344 *(volatile u32 *)&ebx = M.x86.R_EBX;
345 *(volatile u32 *)&esi = M.x86.R_ESI;
346 *(volatile u32 *)&edi = M.x86.R_EDI;
347 flags = M.x86.R_EFLG;
348
349 /* Pass success or error back to our caller via the CARRY flag */
350 if (ret) {
351 flags &= ~1; /* no error: clear carry */
352 } else {
353 debug("int%02x call returned error\n", intnumber);
354 flags |= 1; /* error: set carry */
355 }
356 *(volatile u16 *)&stackflags = flags;
357
358 return ret;
359 }
360