| blob | 9e6ba6f0756e92d56b645ddefc3cc32cd3a8ddfa |
1 /*
2 * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 *
18 */
20 FILE_LICENCE ( GPL2_OR_LATER )
22 .arch i386
24 /**
25 * High memory temporary load address
26 *
27 * Temporary buffer into which to copy (or decompress) our runtime
28 * image, prior to calling get_memmap() and relocate(). We don't
29 * actually leave anything here once install() has returned.
30 *
31 * We use the start of an even megabyte so that we don't have to worry
32 * about the current state of the A20 line.
33 *
34 * We use 4MB rather than 2MB because some PXE stack / PMM BIOS
35 * combinations are known to place data required by other UNDI ROMs
36 * loader around the 2MB mark.
37 */
38 .globl HIGHMEM_LOADPOINT
39 .equ HIGHMEM_LOADPOINT, ( 4 << 20 )
41 /* Image compression enabled */
42 #define COMPRESS 1
44 #define CR0_PE 1
46 /*****************************************************************************
47 * Utility function: print character (with LF -> LF,CR translation)
48 *
49 * Parameters:
50 * %al : character to print
51 * %ds:di : output buffer (or %di=0 to print to console)
52 * Returns:
53 * %ds:di : next character in output buffer (if applicable)
54 *****************************************************************************
55 */
56 .section ".prefix.lib", "awx", @progbits
57 .code16
58 .globl print_character
59 print_character:
60 /* Preserve registers */
61 pushw %ax
62 pushw %bx
63 pushw %bp
64 /* If %di is non-zero, write character to buffer and exit */
65 testw %di, %di
66 jz 1f
67 movb %al, %ds:(%di)
68 incw %di
69 jmp 3f
70 1: /* Print character */
71 movw $0x0007, %bx /* page 0, attribute 7 (normal) */
72 movb $0x0e, %ah /* write char, tty mode */
73 cmpb $0x0a, %al /* '\n'? */
74 jne 2f
75 int $0x10
76 movb $0x0d, %al
77 2: int $0x10
78 /* Restore registers and return */
79 3: popw %bp
80 popw %bx
81 popw %ax
82 ret
83 .size print_character, . - print_character
85 /*****************************************************************************
86 * Utility function: print a NUL-terminated string
87 *
88 * Parameters:
89 * %ds:si : string to print
90 * %ds:di : output buffer (or %di=0 to print to console)
91 * Returns:
92 * %ds:si : character after terminating NUL
93 * %ds:di : next character in output buffer (if applicable)
94 *****************************************************************************
95 */
96 .section ".prefix.lib", "awx", @progbits
97 .code16
98 .globl print_message
99 print_message:
100 /* Preserve registers */
101 pushw %ax
102 /* Print string */
103 1: lodsb
104 testb %al, %al
105 je 2f
106 call print_character
107 jmp 1b
108 2: /* Restore registers and return */
109 popw %ax
110 ret
111 .size print_message, . - print_message
113 /*****************************************************************************
114 * Utility functions: print hex digit/byte/word/dword
115 *
116 * Parameters:
117 * %al (low nibble) : digit to print
118 * %al : byte to print
119 * %ax : word to print
120 * %eax : dword to print
121 * %ds:di : output buffer (or %di=0 to print to console)
122 * Returns:
123 * %ds:di : next character in output buffer (if applicable)
124 *****************************************************************************
125 */
126 .section ".prefix.lib", "awx", @progbits
127 .code16
128 .globl print_hex_dword
129 print_hex_dword:
130 rorl $16, %eax
131 call print_hex_word
132 rorl $16, %eax
133 /* Fall through */
134 .size print_hex_dword, . - print_hex_dword
135 .globl print_hex_word
136 print_hex_word:
137 xchgb %al, %ah
138 call print_hex_byte
139 xchgb %al, %ah
140 /* Fall through */
141 .size print_hex_word, . - print_hex_word
142 .globl print_hex_byte
143 print_hex_byte:
144 rorb $4, %al
145 call print_hex_nibble
146 rorb $4, %al
147 /* Fall through */
148 .size print_hex_byte, . - print_hex_byte
149 .globl print_hex_nibble
150 print_hex_nibble:
151 /* Preserve registers */
152 pushw %ax
153 /* Print digit (technique by Norbert Juffa <norbert.juffa@amd.com> */
154 andb $0x0f, %al
155 cmpb $10, %al
156 sbbb $0x69, %al
157 das
158 call print_character
159 /* Restore registers and return */
160 popw %ax
161 ret
162 .size print_hex_nibble, . - print_hex_nibble
164 /*****************************************************************************
165 * Utility function: print PCI bus:dev.fn
166 *
167 * Parameters:
168 * %ax : PCI bus:dev.fn to print
169 * %ds:di : output buffer (or %di=0 to print to console)
170 * Returns:
171 * %ds:di : next character in output buffer (if applicable)
172 *****************************************************************************
173 */
174 .section ".prefix.lib", "awx", @progbits
175 .code16
176 .globl print_pci_busdevfn
177 print_pci_busdevfn:
178 /* Preserve registers */
179 pushw %ax
180 /* Print bus */
181 xchgb %al, %ah
182 call print_hex_byte
183 /* Print ":" */
184 movb $( ':' ), %al
185 call print_character
186 /* Print device */
187 movb %ah, %al
188 shrb $3, %al
189 call print_hex_byte
190 /* Print "." */
191 movb $( '.' ), %al
192 call print_character
193 /* Print function */
194 movb %ah, %al
195 andb $0x07, %al
196 call print_hex_nibble
197 /* Restore registers and return */
198 popw %ax
199 ret
200 .size print_pci_busdevfn, . - print_pci_busdevfn
202 /*****************************************************************************
203 * Utility function: clear current line
204 *
205 * Parameters:
206 * %ds:di : output buffer (or %di=0 to print to console)
207 * Returns:
208 * %ds:di : next character in output buffer (if applicable)
209 *****************************************************************************
210 */
211 .section ".prefix.lib", "awx", @progbits
212 .code16
213 .globl print_kill_line
214 print_kill_line:
215 /* Preserve registers */
216 pushw %ax
217 pushw %cx
218 /* Print CR */
219 movb $( '\r' ), %al
220 call print_character
221 /* Print 79 spaces */
222 movb $( ' ' ), %al
223 movw $79, %cx
224 1: call print_character
225 loop 1b
226 /* Print CR */
227 movb $( '\r' ), %al
228 call print_character
229 /* Restore registers and return */
230 popw %cx
231 popw %ax
232 ret
233 .size print_kill_line, . - print_kill_line
235 /****************************************************************************
236 * pm_call (real-mode near call)
237 *
238 * Call routine in 16-bit protected mode for access to extended memory
239 *
240 * Parameters:
241 * %ax : address of routine to call in 16-bit protected mode
242 * Returns:
243 * none
244 * Corrupts:
245 * %ax
246 *
247 * The specified routine is called in 16-bit protected mode, with:
248 *
249 * %cs : 16-bit code segment with base matching real-mode %cs
250 * %ss : 16-bit data segment with base matching real-mode %ss
251 * %ds,%es,%fs,%gs : 32-bit data segment with zero base and 4GB limit
252 *
253 ****************************************************************************
254 */
256 #ifndef KEEP_IT_REAL
258 /* GDT for protected-mode calls */
259 .section ".prefix.lib", "awx", @progbits
260 .align 16
261 pm_call_vars:
262 gdt:
263 gdt_limit: .word gdt_length - 1
264 gdt_base: .long 0
265 .word 0 /* padding */
266 pm_cs: /* 16-bit protected-mode code segment */
267 .equ PM_CS, pm_cs - gdt
268 .word 0xffff, 0
269 .byte 0, 0x9b, 0x00, 0
270 pm_ss: /* 16-bit protected-mode stack segment */
271 .equ PM_SS, pm_ss - gdt
272 .word 0xffff, 0
273 .byte 0, 0x93, 0x00, 0
274 pm_ds: /* 32-bit protected-mode flat data segment */
275 .equ PM_DS, pm_ds - gdt
276 .word 0xffff, 0
277 .byte 0, 0x93, 0xcf, 0
278 gdt_end:
279 .equ gdt_length, . - gdt
280 .size gdt, . - gdt
282 .section ".prefix.lib", "awx", @progbits
283 .align 16
284 pm_saved_gdt:
285 .long 0, 0
286 .size pm_saved_gdt, . - pm_saved_gdt
288 .equ pm_call_vars_size, . - pm_call_vars
289 #define PM_CALL_VAR(x) ( -pm_call_vars_size + ( (x) - pm_call_vars ) )
291 .section ".prefix.lib", "awx", @progbits
292 .code16
293 pm_call:
294 /* Preserve registers, flags, and RM return point */
295 pushw %bp
296 movw %sp, %bp
297 subw $pm_call_vars_size, %sp
298 andw $0xfff0, %sp
299 pushfl
300 pushw %gs
301 pushw %fs
302 pushw %es
303 pushw %ds
304 pushw %ss
305 pushw %cs
306 pushw $99f
308 /* Set up local variable block, and preserve GDT */
309 pushw %cx
310 pushw %si
311 pushw %di
312 pushw %ss
313 popw %es
314 movw $pm_call_vars, %si
315 leaw PM_CALL_VAR(pm_call_vars)(%bp), %di
316 movw $pm_call_vars_size, %cx
317 cs rep movsb
318 popw %di
319 popw %si
320 popw %cx
321 sgdt PM_CALL_VAR(pm_saved_gdt)(%bp)
323 /* Set up GDT bases */
324 pushl %eax
325 pushl %edi
326 xorl %eax, %eax
327 movw %ss, %ax
328 shll $4, %eax
329 movzwl %bp, %edi
330 addr32 leal PM_CALL_VAR(gdt)(%eax, %edi), %eax
331 movl %eax, PM_CALL_VAR(gdt_base)(%bp)
332 movw %cs, %ax
333 movw $PM_CALL_VAR(pm_cs), %di
334 call set_seg_base
335 movw %ss, %ax
336 movw $PM_CALL_VAR(pm_ss), %di
337 call set_seg_base
338 popl %edi
339 popl %eax
341 /* Switch CPU to protected mode and load up segment registers */
342 pushl %eax
343 cli
344 data32 lgdt PM_CALL_VAR(gdt)(%bp)
345 movl %cr0, %eax
346 orb $CR0_PE, %al
347 movl %eax, %cr0
348 ljmp $PM_CS, $1f
349 1: movw $PM_SS, %ax
350 movw %ax, %ss
351 movw $PM_DS, %ax
352 movw %ax, %ds
353 movw %ax, %es
354 movw %ax, %fs
355 movw %ax, %gs
356 popl %eax
358 /* Call PM routine */
359 call *%ax
361 /* Set real-mode segment limits on %ds, %es, %fs and %gs */
362 movw %ss, %ax
363 movw %ax, %ds
364 movw %ax, %es
365 movw %ax, %fs
366 movw %ax, %gs
368 /* Return CPU to real mode */
369 movl %cr0, %eax
370 andb $0!CR0_PE, %al
371 movl %eax, %cr0
373 /* Restore registers and flags */
374 lret /* will ljmp to 99f */
375 99: popw %ss
376 popw %ds
377 popw %es
378 popw %fs
379 popw %gs
380 data32 lgdt PM_CALL_VAR(pm_saved_gdt)(%bp)
381 popfl
382 movw %bp, %sp
383 popw %bp
384 ret
385 .size pm_call, . - pm_call
387 set_seg_base:
388 rolw $4, %ax
389 movw %ax, 2(%bp,%di)
390 andw $0xfff0, 2(%bp,%di)
391 movb %al, 4(%bp,%di)
392 andb $0x0f, 4(%bp,%di)
393 ret
394 .size set_seg_base, . - set_seg_base
396 #endif /* KEEP_IT_REAL */
398 /****************************************************************************
399 * copy_bytes (real-mode or 16-bit protected-mode near call)
400 *
401 * Copy bytes
402 *
403 * Parameters:
404 * %ds:esi : source address
405 * %es:edi : destination address
406 * %ecx : length
407 * Returns:
408 * %ds:esi : next source address
409 * %es:edi : next destination address
410 * Corrupts:
411 * None
412 ****************************************************************************
413 */
414 .section ".prefix.lib", "awx", @progbits
415 .code16
416 copy_bytes:
417 pushl %ecx
418 rep addr32 movsb
419 popl %ecx
420 ret
421 .size copy_bytes, . - copy_bytes
423 /****************************************************************************
424 * install_block (real-mode near call)
425 *
426 * Install block to specified address
427 *
428 * Parameters:
429 * %esi : source physical address (must be a multiple of 16)
430 * %edi : destination physical address (must be a multiple of 16)
431 * %ecx : length of (decompressed) data
432 * %edx : total length of block (including any uninitialised data portion)
433 * Returns:
434 * %esi : next source physical address (will be a multiple of 16)
435 * Corrupts:
436 * none
437 ****************************************************************************
438 */
439 .section ".prefix.lib", "awx", @progbits
440 .code16
441 install_block:
443 #ifdef KEEP_IT_REAL
445 /* Preserve registers */
446 pushw %ds
447 pushw %es
448 pushl %ecx
449 pushl %edi
451 /* Convert %esi and %edi to segment registers */
452 shrl $4, %esi
453 movw %si, %ds
454 xorw %si, %si
455 shrl $4, %edi
456 movw %di, %es
457 xorw %di, %di
459 #else /* KEEP_IT_REAL */
461 /* Call self in protected mode */
462 pushw %ax
463 movw $1f, %ax
464 call pm_call
465 popw %ax
466 ret
467 1:
468 /* Preserve registers */
469 pushl %ecx
470 pushl %edi
472 #endif /* KEEP_IT_REAL */
475 #if COMPRESS
476 /* Decompress source to destination */
477 call decompress16
478 #else
479 /* Copy source to destination */
480 call copy_bytes
481 #endif
483 /* Zero .bss portion */
484 negl %ecx
485 addl %edx, %ecx
486 pushw %ax
487 xorw %ax, %ax
488 rep addr32 stosb
489 popw %ax
491 /* Round up %esi to start of next source block */
492 addl $0xf, %esi
493 andl $~0xf, %esi
496 #ifdef KEEP_IT_REAL
498 /* Convert %ds:esi back to a physical address */
499 movzwl %ds, %cx
500 shll $4, %ecx
501 addl %ecx, %esi
503 /* Restore registers */
504 popl %edi
505 popl %ecx
506 popw %es
507 popw %ds
509 #else /* KEEP_IT_REAL */
511 /* Restore registers */
512 popl %edi
513 popl %ecx
515 #endif
517 ret
518 .size install_block, . - install_block
520 /****************************************************************************
521 * alloc_basemem (real-mode near call)
522 *
523 * Allocate space for .text16 and .data16 from top of base memory.
524 * Memory is allocated using the BIOS free base memory counter at
525 * 0x40:13.
526 *
527 * Parameters:
528 * none
529 * Returns:
530 * %ax : .text16 segment address
531 * %bx : .data16 segment address
532 * Corrupts:
533 * none
534 ****************************************************************************
535 */
536 .section ".prefix.lib", "awx", @progbits
537 .code16
538 .globl alloc_basemem
539 alloc_basemem:
540 /* Preserve registers */
541 pushw %fs
543 /* FBMS => %ax as segment address */
544 pushw $0x40
545 popw %fs
546 movw %fs:0x13, %ax
547 shlw $6, %ax
549 /* Calculate .data16 segment address */
550 subw $_data16_memsz_pgh, %ax
551 pushw %ax
553 /* Calculate .text16 segment address */
554 subw $_text16_memsz_pgh, %ax
555 pushw %ax
557 /* Update FBMS */
558 shrw $6, %ax
559 movw %ax, %fs:0x13
561 /* Retrieve .text16 and .data16 segment addresses */
562 popw %ax
563 popw %bx
565 /* Restore registers and return */
566 popw %fs
567 ret
568 .size alloc_basemem, . - alloc_basemem
570 /****************************************************************************
571 * free_basemem (real-mode near call)
572 *
573 * Free space allocated with alloc_basemem.
574 *
575 * Parameters:
576 * %ax : .text16 segment address
577 * %bx : .data16 segment address
578 * Returns:
579 * %ax : 0 if successfully freed
580 * Corrupts:
581 * none
582 ****************************************************************************
583 */
584 .section ".text16", "ax", @progbits
585 .code16
586 .globl free_basemem
587 free_basemem:
588 /* Preserve registers */
589 pushw %fs
591 /* Check FBMS counter */
592 pushw %ax
593 shrw $6, %ax
594 pushw $0x40
595 popw %fs
596 cmpw %ax, %fs:0x13
597 popw %ax
598 jne 1f
600 /* Check hooked interrupt count */
601 cmpw $0, %cs:hooked_bios_interrupts
602 jne 1f
604 /* OK to free memory */
605 addw $_text16_memsz_pgh, %ax
606 addw $_data16_memsz_pgh, %ax
607 shrw $6, %ax
608 movw %ax, %fs:0x13
609 xorw %ax, %ax
611 1: /* Restore registers and return */
612 popw %fs
613 ret
614 .size free_basemem, . - free_basemem
616 .section ".text16.data", "aw", @progbits
617 .globl hooked_bios_interrupts
618 hooked_bios_interrupts:
619 .word 0
620 .size hooked_bios_interrupts, . - hooked_bios_interrupts
622 /****************************************************************************
623 * install (real-mode near call)
624 *
625 * Install all text and data segments.
626 *
627 * Parameters:
628 * none
629 * Returns:
630 * %ax : .text16 segment address
631 * %bx : .data16 segment address
632 * Corrupts:
633 * none
634 ****************************************************************************
635 */
636 .section ".prefix.lib", "awx", @progbits
637 .code16
638 .globl install
639 install:
640 /* Preserve registers */
641 pushl %esi
642 pushl %edi
643 /* Allocate space for .text16 and .data16 */
644 call alloc_basemem
645 /* Image source = %cs:0000 */
646 xorl %esi, %esi
647 /* Image destination = HIGHMEM_LOADPOINT */
648 movl $HIGHMEM_LOADPOINT, %edi
649 /* Install text and data segments */
650 call install_prealloc
651 /* Restore registers and return */
652 popl %edi
653 popl %esi
654 ret
655 .size install, . - install
657 /****************************************************************************
658 * install_prealloc (real-mode near call)
659 *
660 * Install all text and data segments.
661 *
662 * Parameters:
663 * %ax : .text16 segment address
664 * %bx : .data16 segment address
665 * %esi : Image source physical address (or zero for %cs:0000)
666 * %edi : Decompression temporary area physical address
667 * Corrupts:
668 * none
669 ****************************************************************************
670 */
671 .section ".prefix.lib", "awx", @progbits
672 .code16
673 .globl install_prealloc
674 install_prealloc:
675 /* Save registers */
676 pushal
677 pushw %ds
678 pushw %es
680 /* Sanity: clear the direction flag asap */
681 cld
683 /* Calculate physical address of payload (i.e. first source) */
684 testl %esi, %esi
685 jnz 1f
686 movw %cs, %si
687 shll $4, %esi
688 1: addl $_payload_lma, %esi
690 /* Install .text16 and .data16 */
691 pushl %edi
692 movzwl %ax, %edi
693 shll $4, %edi
694 movl $_text16_memsz, %ecx
695 movl %ecx, %edx
696 call install_block /* .text16 */
697 movzwl %bx, %edi
698 shll $4, %edi
699 movl $_data16_filesz, %ecx
700 movl $_data16_memsz, %edx
701 call install_block /* .data16 */
702 popl %edi
704 /* Set up %ds for access to .data16 */
705 movw %bx, %ds
707 #ifdef KEEP_IT_REAL
708 /* Initialise libkir */
709 movw %ax, (init_libkir_vector+2)
710 lcall *init_libkir_vector
711 #else
712 /* Install .text and .data to temporary area in high memory,
713 * prior to reading the E820 memory map and relocating
714 * properly.
715 */
716 movl $_textdata_filesz, %ecx
717 movl $_textdata_memsz, %edx
718 call install_block
720 /* Initialise librm at current location */
721 movw %ax, (init_librm_vector+2)
722 lcall *init_librm_vector
724 /* Call relocate() to determine target address for relocation.
725 * relocate() will return with %esi, %edi and %ecx set up
726 * ready for the copy to the new location.
727 */
728 movw %ax, (prot_call_vector+2)
729 pushl $relocate
730 lcall *prot_call_vector
731 popl %edx /* discard */
733 /* Copy code to new location */
734 pushl %edi
735 pushw %ax
736 movw $copy_bytes, %ax
737 call pm_call
738 popw %ax
739 popl %edi
741 /* Initialise librm at new location */
742 lcall *init_librm_vector
744 #endif
745 /* Restore registers */
746 popw %es
747 popw %ds
748 popal
749 ret
750 .size install_prealloc, . - install_prealloc
752 /* Vectors for far calls to .text16 functions */
753 .section ".data16", "aw", @progbits
754 #ifdef KEEP_IT_REAL
755 init_libkir_vector:
756 .word init_libkir
757 .word 0
758 .size init_libkir_vector, . - init_libkir_vector
759 #else
760 init_librm_vector:
761 .word init_librm
762 .word 0
763 .size init_librm_vector, . - init_librm_vector
764 prot_call_vector:
765 .word prot_call
766 .word 0
767 .size prot_call_vector, . - prot_call_vector
768 #endif
770 /****************************************************************************
771 * uninstall (real-mode near call)
772 *
773 * Uninstall all text and data segments.
774 *
775 * Parameters:
776 * %ax : .text16 segment address
777 * %bx : .data16 segment address
778 * Returns:
779 * none
780 * Corrupts:
781 * none
782 ****************************************************************************
783 */
784 .section ".text16", "ax", @progbits
785 .code16
786 .globl uninstall
787 uninstall:
788 call free_basemem
789 ret
790 .size uninstall, . - uninstall
794 /* File split information for the compressor */
795 #if COMPRESS
796 .section ".zinfo", "a", @progbits
797 .ascii "COPY"
798 .long _prefix_lma
799 .long _prefix_filesz
800 .long _max_align
801 .ascii "PACK"
802 .long _text16_lma
803 .long _text16_filesz
804 .long _max_align
805 .ascii "PACK"
806 .long _data16_lma
807 .long _data16_filesz
808 .long _max_align
809 .ascii "PACK"
810 .long _textdata_lma
811 .long _textdata_filesz
812 .long _max_align
813 #else /* COMPRESS */
814 .section ".zinfo", "a", @progbits
815 .ascii "COPY"
816 .long _prefix_lma
817 .long _filesz
818 .long _max_align
819 #endif /* COMPRESS */