summaryrefslogtreecommitdiffstats
path: root/qemu/roms/seabios/src/romlayout.S
blob: 53cc0f5e3d45c51dc263757b08871309d8a0d1a0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
// Rom layout and bios assembler to C interface.
//
// Copyright (C) 2008-2012  Kevin O'Connor <kevin@koconnor.net>
// Copyright (C) 2002  MandrakeSoft S.A.
//
// This file may be distributed under the terms of the GNU LGPLv3 license.

#include "asm-offsets.h" // BREGS_*
#include "config.h" // CONFIG_*
#include "entryfuncs.S" // ENTRY_*
#include "hw/rtc.h" // CMOS_RESET_CODE
#include "x86.h" // CR0_*

        .code16


/****************************************************************
 * 16bit / 32bit call trampolines
 ****************************************************************/

// Place CPU into 32bit mode from 16bit mode.
// %edx = return location (in 32bit mode)
// Clobbers: ecx, flags, segment registers, cr0, idt/gdt
        DECLFUNC transition32
        .global transition32_nmi_off
transition32:
        // Disable irqs (and clear direction flag)
        cli
        cld

        // Disable nmi
        movl %eax, %ecx
        movl $CMOS_RESET_CODE|NMI_DISABLE_BIT, %eax
        outb %al, $PORT_CMOS_INDEX
        inb $PORT_CMOS_DATA, %al

        // enable a20
        inb $PORT_A20, %al
        orb $A20_ENABLE_BIT, %al
        outb %al, $PORT_A20
        movl %ecx, %eax

transition32_nmi_off:
        // Set segment descriptors
        lidtw %cs:pmode_IDT_info
        lgdtw %cs:rombios32_gdt_48

        // Enable protected mode
        movl %cr0, %ecx
        andl $~(CR0_PG|CR0_CD|CR0_NW), %ecx
        orl $CR0_PE, %ecx
        movl %ecx, %cr0

        // start 32bit protected mode code
        ljmpl $SEG32_MODE32_CS, $(BUILD_BIOS_ADDR + 1f)

        .code32
        // init data segments
1:      movl $SEG32_MODE32_DS, %ecx
        movw %cx, %ds
        movw %cx, %es
        movw %cx, %ss
        movw %cx, %fs
        movw %cx, %gs

        jmpl *%edx
        .code16

// Place CPU into 16bit mode from 32bit mode.
// %edx = return location (in 16bit mode)
// Clobbers: ecx, flags, segment registers, cr0, idt/gdt
        DECLFUNC transition16
        .global transition16big
        .code32
transition16:
        // Reset data segment limits
        movl $SEG32_MODE16_DS, %ecx
        movw %cx, %ds
        movw %cx, %es
        movw %cx, %ss
        movw %cx, %fs
        movw %cx, %gs

        // Jump to 16bit mode
        ljmpw $SEG32_MODE16_CS, $1f

transition16big:
        movl $SEG32_MODE16BIG_DS, %ecx
        movw %cx, %ds
        movw %cx, %es
        movw %cx, %ss
        movw %cx, %fs
        movw %cx, %gs

        ljmpw $SEG32_MODE16BIG_CS, $1f

        .code16
        // Disable protected mode
1:      movl %cr0, %ecx
        andl $~CR0_PE, %ecx
        movl %ecx, %cr0

        // far jump to flush CPU queue after transition to real mode
        ljmpw $SEG_BIOS, $2f

        // restore IDT to normal real-mode defaults
2:      lidtw %cs:rmode_IDT_info

        // Clear segment registers
        xorw %cx, %cx
        movw %cx, %fs
        movw %cx, %gs
        movw %cx, %es
        movw %cx, %ds
        movw %cx, %ss  // Assume stack is in segment 0

        jmpl *%edx


/****************************************************************
 * External calling trampolines
 ****************************************************************/

// Far call a 16bit function from 16bit mode with a specified cpu register state
// %eax = address of struct bregs, %edx = segment of struct bregs
// Clobbers: %e[bc]x, %e[ds]i, flags
        DECLFUNC __farcall16
__farcall16:
        // Save %edx/%eax, %ebp
        pushl %ebp
        pushl %eax
        pushl %edx

        // Setup for iretw call
        movl %edx, %ds
        pushw %cs
        pushw $1f                       // return point
        pushw BREGS_flags(%eax)         // flags
        pushl BREGS_code(%eax)          // CS:IP

        // Load calling registers and invoke call
        RESTOREBREGS_DSEAX
        iretw                           // XXX - just do a lcalll
1:
        // Store flags, es, eax
        pushfw
        cli
        cld
        pushw %ds
        pushl %eax
        movw 0x08(%esp), %ds
        movl 0x0c(%esp), %eax
        SAVEBREGS_POP_DSEAX
        popw BREGS_flags(%eax)
        movw %ss, %cx
        movw %cx, %ds                   // Restore %ds == %ss

        // Remove %edx/%eax, restore %ebp
        popl %edx
        popl %eax
        popl %ebp

        retl

// IRQ trampolines
        .macro IRQ_TRAMPOLINE num
        DECLFUNC irq_trampoline_0x\num
        irq_trampoline_0x\num :
        int $0x\num
        lretw
        .endm

        IRQ_TRAMPOLINE 02
        IRQ_TRAMPOLINE 10
        IRQ_TRAMPOLINE 13
        IRQ_TRAMPOLINE 15
        IRQ_TRAMPOLINE 16
        IRQ_TRAMPOLINE 18
        IRQ_TRAMPOLINE 19
        IRQ_TRAMPOLINE 1c
        IRQ_TRAMPOLINE 4a


/****************************************************************
 * Misc. entry points.
 ****************************************************************/

// Entry point for QEMU smi interrupts.
        DECLFUNC entry_smi
entry_smi:
        // Transition to 32bit mode.
        movl $1f + BUILD_BIOS_ADDR, %edx
        jmp transition32_nmi_off
        .code32
1:      movl $BUILD_SMM_ADDR + 0x8000, %esp
        calll _cfunc32flat_handle_smi - BUILD_BIOS_ADDR
        rsm
        .code16

// Entry point for QEMU smp sipi interrupts.
        DECLFUNC entry_smp
entry_smp:
        // Transition to 32bit mode.
        cli
        cld
        movl $2f + BUILD_BIOS_ADDR, %edx
        jmp transition32_nmi_off
        .code32
        // Acquire lock and take ownership of shared stack
1:      rep ; nop
2:      lock btsl $0, SMPLock
        jc 1b
        movl SMPStack, %esp
        // Call handle_smp
        calll _cfunc32flat_handle_smp - BUILD_BIOS_ADDR
        // Release lock and halt processor.
        movl $0, SMPLock
3:      hlt
        jmp 3b
        .code16

// Resume (and reboot) entry point - called from entry_post
        DECLFUNC entry_resume
entry_resume:
        // Disable interrupts
        cli
        cld
        // Use the ExtraStack in low mem.
        movl $_zonelow_seg, %eax
        movw %ax, %ds
        movw %ax, %ss
        movl $ExtraStack + BUILD_EXTRA_STACK_SIZE, %esp
        // Call handler.
        jmp handle_resume

// PMM entry point
        DECLFUNC entry_pmm
entry_pmm:
        pushl %esp              // Backup %esp, then clear high bits
        movzwl %sp, %esp
        pushfl                  // Save registers clobbered by C code
        cli
        cld
        PUSHBREGS
        movl %ss, %ecx          // Move %ss to %ds
        movw %cx, %ds
        shll $4, %ecx
        movl $_cfunc32flat_handle_pmm, %eax // Setup: call32(handle_pmm, args, -1)
        leal PUSHBREGS_size+12(%esp, %ecx), %edx // %edx points to start of args
        movl $-1, %ecx
        calll __call32
        movw %ax, BREGS_eax(%esp)       // Modify %ax:%dx to return %eax
        shrl $16, %eax
        movw %ax, BREGS_edx(%esp)
        POPBREGS
        popfl
        popl %esp
        lretw

// PnP entry points
        DECLFUNC entry_pnp_real
        .global entry_pnp_prot
entry_pnp_prot:
        pushl %esp
        jmp 1f
entry_pnp_real:
        pushl %esp              // Backup %esp, then clear high bits
        movzwl %sp, %esp
1:
        pushfl                  // Save registers clobbered by C code
        cli
        cld
        PUSHBREGS
        movw %ss, %cx           // Move %ss to %ds
        movw %cx, %ds
        leal PUSHBREGS_size+12(%esp), %eax  // %eax points to start of u16 args
        calll handle_pnp
        movw %ax, BREGS_eax(%esp)   // Modify %eax to return %ax
        POPBREGS
        popfl
        popl %esp
        lretw

// APM entry points
        DECLFUNC entry_apm16
entry_apm16:
        pushfw          // save flags
        pushl %eax      // dummy
        ENTRY_ARG handle_apm
        addw $4, %sp    // pop dummy
        popfw           // restore flags
        lretw

        DECLFUNC entry_apm32
        .code32
entry_apm32:
        pushfl
        pushl %gs
        pushl %cs               // Move second descriptor after %cs to %gs
        addl $16, (%esp)
        popl %gs
        ENTRY_ARG_ESP _cfunc32seg_handle_apm
        popl %gs
        popfl
        lretl
        .code16

// PCI-BIOS entry points
        DECLFUNC entry_pcibios32
        .code32
entry_pcibios32:
        pushfl
        pushl %gs               // Backup %gs and set %gs=%ds
        pushl %ds
        popl %gs
        ENTRY_ARG_ESP _cfunc32seg_handle_pcibios
        popl %gs
        popfl
        lretl
        .code16

        DECLFUNC entry_pcibios16
entry_pcibios16:
        ENTRY_ARG handle_pcibios
        iretw

// int 1589 entry point
        DECLFUNC entry_1589
entry_1589:
        ENTRY_ARG handle_1589
        iretw

// BIOS32 support
        DECLFUNC entry_bios32
        .code32
entry_bios32:
        pushfl
#if CONFIG_PCIBIOS
        // Check for PCI-BIOS request
        cmpl $0x49435024, %eax // $PCI
        jne 1f
        movl $BUILD_BIOS_ADDR, %ebx
        movl $BUILD_BIOS_SIZE, %ecx
        movl $entry_pcibios32, %edx
        xorb %al, %al
        jmp 2f
#endif
        // Unknown request
1:      movb $0x80, %al
        // Return to caller
2:      popfl
        lretl
        .code16

// 32bit elf entry point
        DECLFUNC entry_elf
        .code32
entry_elf:
        cli
        cld
        movl %eax, entry_elf_eax
        movl %ebx, entry_elf_ebx
        lidtl (BUILD_BIOS_ADDR + pmode_IDT_info)
        lgdtl (BUILD_BIOS_ADDR + rombios32_gdt_48)
        movl $SEG32_MODE32_DS, %eax
        movw %ax, %ds
        movw %ax, %es
        movw %ax, %fs
        movw %ax, %gs
        movw %ax, %ss
        movl $BUILD_STACK_ADDR, %esp
        ljmpl $SEG32_MODE32_CS, $_cfunc32flat_handle_post
        .code16

// UEFI Compatibility Support Module (CSM) entry point
        DECLFUNC entry_csm
entry_csm:
        // Backup register state
        pushfw
        cli
        cld
        pushl %eax                      // dummy
        PUSHBREGS

        // Backup stack location and convert to a "flat pointer"
        movl %ss, %eax
        movw %ax, BREGS_code+2(%esp)    // Store %ss in bregs->code.seg
        shll $4, %eax
        addl %esp, %eax

        // Change to BUILD_STACK_ADDR stack and call handle_csm(bregs)
        ENTRY_INTO32 _cfunc32flat_handle_csm

        DECLFUNC __csm_return
        .code32
__csm_return:
        movl $1f, %edx
        jmp transition16big
        .code16

        // Switch back to original stack
1:      movzwl BREGS_code+2(%eax), %edx
        movl %edx, %ecx
        shll $4, %ecx
        subl %ecx, %eax
        movl %edx, %ss
        movl %eax, %esp

        // Restore register state and return.
        POPBREGS
        addw $4, %sp                    // pop dummy
        popfw
        lretw


/****************************************************************
 * Interrupt entry points
 ****************************************************************/

        // Main entry point for hardware interrupts handled on extra stack
        DECLFUNC irqentry_extrastack
irqentry_extrastack:
        cli
        cld
        pushw %ds               // Set %ds:%eax to space on ExtraStack
        pushl %eax
        movl $_zonelow_seg, %eax
        movl %eax, %ds
        movl StackPos, %eax
        subl $PUSHBREGS_size+8, %eax
        SAVEBREGS_POP_DSEAX
        popl %ecx
        movl %esp, PUSHBREGS_size(%eax)
        movw %ss, PUSHBREGS_size+4(%eax)

        movw %ds, %dx           // Setup %ss/%esp and call function
        movw %dx, %ss
        movl %eax, %esp
        calll *%ecx

        movl %esp, %eax         // Restore registers and return
        movw PUSHBREGS_size+4(%eax), %ss
        movl PUSHBREGS_size(%eax), %esp
        RESTOREBREGS_DSEAX
        iretw

        // Main entry point for software interrupts handled on extra stack
        DECLFUNC irqentry_arg_extrastack
irqentry_arg_extrastack:
        cli
        cld
        pushw %ds               // Set %ds:%eax to space on ExtraStack
        pushl %eax
        movl $_zonelow_seg, %eax
        movl %eax, %ds
        movl StackPos, %eax
        subl $PUSHBREGS_size+16, %eax
        SAVEBREGS_POP_DSEAX     // Save registers on extra stack
        popl %ecx
        movl %esp, PUSHBREGS_size+8(%eax)
        movw %ss, PUSHBREGS_size+12(%eax)
        popl BREGS_code(%eax)
        popw BREGS_flags(%eax)

        movw %ds, %dx           // Setup %ss/%esp and call function
        movw %dx, %ss
        movl %eax, %esp
        calll *%ecx

        movl %esp, %eax         // Restore registers and return
        movw PUSHBREGS_size+12(%eax), %ss
        movl PUSHBREGS_size+8(%eax), %esp
        popl %edx
        popw %dx
        pushw BREGS_flags(%eax)
        pushl BREGS_code(%eax)
        RESTOREBREGS_DSEAX
        iretw

        // Main entry point for software interrupts (using caller's stack)
        DECLFUNC irqentry_arg
irqentry_arg:
        ENTRY_ARG_ST
        iretw

        // Helper macros for hardware interrupt declaration
        .macro IRQ_ENTRY num
        .global entry_\num
        entry_\num :
        pushl $ handle_\num
        jmp irqentry_extrastack
        .endm

        .macro DECL_IRQ_ENTRY num
        DECLFUNC entry_\num
        IRQ_ENTRY \num
        .endm

        // Helper macros for software interrupt declaration
        .macro IRQ_ENTRY_ARG num
        .global entry_\num
        entry_\num :
        pushl $ handle_\num
#if CONFIG_ENTRY_EXTRASTACK
        jmp irqentry_arg_extrastack
#else
        jmp irqentry_arg
#endif
        .endm

        .macro DECL_IRQ_ENTRY_ARG num
        DECLFUNC entry_\num
        IRQ_ENTRY_ARG \num
        .endm

        // Various entry points (that don't require a fixed location).
        DECL_IRQ_ENTRY_ARG 13
        DECL_IRQ_ENTRY 76
        DECL_IRQ_ENTRY 70
        DECL_IRQ_ENTRY 74
        DECL_IRQ_ENTRY 75
        DECL_IRQ_ENTRY hwpic1
        DECL_IRQ_ENTRY hwpic2

        // int 18/19 are special - they reset stack and call into 32bit mode.
        DECLFUNC entry_19
entry_19:
        ENTRY_INTO32 _cfunc32flat_handle_19

        DECLFUNC entry_18
entry_18:
        ENTRY_INTO32 _cfunc32flat_handle_18


/****************************************************************
 * Fixed position entry points
 ****************************************************************/

        // Specify a location in the fixed part of bios area.
        .macro ORG addr
        .section .fixedaddr.\addr
        .endm

        ORG 0xe05b
entry_post:
        cmpl $0, %cs:HaveRunPost                // Check for resume/reboot
        jnz entry_resume
        ENTRY_INTO32 _cfunc32flat_handle_post   // Normal entry point

        ORG 0xe2c3
        .global entry_02
entry_02:
        ENTRY handle_02  // NMI handler does not switch onto extra stack
        iretw

        ORG 0xe3fe
        .global entry_13_official
entry_13_official:
        jmp entry_13

        // 0xe401 - OldFDPT in misc.c

        ORG 0xe6f2
        .global entry_19_official
entry_19_official:
        jmp entry_19

        // 0xe6f5 - BIOS_CONFIG_TABLE in misc.c

        // 0xe729 - BaudTable in misc.c

        ORG 0xe739
        IRQ_ENTRY_ARG 14

        ORG 0xe82e
        IRQ_ENTRY_ARG 16

        ORG 0xe987
        IRQ_ENTRY 09

        ORG 0xec59
        IRQ_ENTRY_ARG 40

        ORG 0xef57
        IRQ_ENTRY 0e

        // 0xefc7 - diskette_param_table in misc.c

        ORG 0xefd2
        IRQ_ENTRY_ARG 17

        ORG 0xf045
entry_10_0x0f:
        // XXX - INT 10 Functions 0-Fh Entry Point
        iretw

        ORG 0xf065
        IRQ_ENTRY_ARG 10

        // 0xf0a4 - VideoParams in misc.c

        ORG 0xf841
        IRQ_ENTRY_ARG 12

        ORG 0xf84d
        IRQ_ENTRY_ARG 11

        ORG 0xf859
        .global entry_15_official
entry_15_official:
        cmpb $0x89, %ah
        je entry_1589           // 1589 calls return in protected mode
        IRQ_ENTRY_ARG 15

        // 0xfa6e - vgafont8 in font.c

        ORG 0xfe6e
        .global entry_1a_official
entry_1a_official:
        cmpb $0xb1, %ah
        je entry_pcibios16      // PCIBIOS calls can be in protected mode
        IRQ_ENTRY_ARG 1a

        ORG 0xfea5
        IRQ_ENTRY 08

        // 0xfef3 - InitVectors in misc.c

        ORG 0xff53
        .global entry_iret_official
entry_iret_official:
        iretw

        ORG 0xff54
        IRQ_ENTRY_ARG 05

        ORG 0xfff0 // Power-up Entry Point
        .global reset_vector
reset_vector:
        ljmpw $SEG_BIOS, $entry_post

        // 0xfff5 - BiosDate in misc.c

        // 0xfffe - BiosModelId in misc.c

        // 0xffff - BiosChecksum in misc.c

        .end