Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * setup.S Copyright (C) 1991, 1992 Linus Torvalds | |
3 | * | |
4 | * setup.s is responsible for getting the system data from the BIOS, | |
5 | * and putting them into the appropriate places in system memory. | |
6 | * both setup.s and system has been loaded by the bootblock. | |
7 | * | |
8 | * This code asks the bios for memory/disk/other parameters, and | |
9 | * puts them in a "safe" place: 0x90000-0x901FF, ie where the | |
10 | * boot-block used to be. It is then up to the protected mode | |
11 | * system to read them from there before the area is overwritten | |
12 | * for buffer-blocks. | |
13 | * | |
14 | * Move PS/2 aux init code to psaux.c | |
15 | * (troyer@saifr00.cfsat.Honeywell.COM) 03Oct92 | |
16 | * | |
17 | * some changes and additional features by Christoph Niemann, | |
18 | * March 1993/June 1994 (Christoph.Niemann@linux.org) | |
19 | * | |
20 | * add APM BIOS checking by Stephen Rothwell, May 1994 | |
21 | * (sfr@canb.auug.org.au) | |
22 | * | |
23 | * High load stuff, initrd support and position independency | |
24 | * by Hans Lermen & Werner Almesberger, February 1996 | |
25 | * <lermen@elserv.ffm.fgan.de>, <almesber@lrc.epfl.ch> | |
26 | * | |
27 | * Video handling moved to video.S by Martin Mares, March 1996 | |
28 | * <mj@k332.feld.cvut.cz> | |
29 | * | |
30 | * Extended memory detection scheme retwiddled by orc@pell.chi.il.us (david | |
31 | * parsons) to avoid loadlin confusion, July 1997 | |
32 | * | |
33 | * Transcribed from Intel (as86) -> AT&T (gas) by Chris Noe, May 1999. | |
34 | * <stiker@northlink.com> | |
35 | * | |
f4549448 | 36 | * Fix to work around buggy BIOSes which don't use carry bit correctly |
1da177e4 LT |
37 | * and/or report extended memory in CX/DX for e801h memory size detection |
38 | * call. As a result the kernel got wrong figures. The int15/e801h docs | |
39 | * from Ralf Brown interrupt list seem to indicate AX/BX should be used | |
40 | * anyway. So to avoid breaking many machines (presumably there was a reason | |
41 | * to orginally use CX/DX instead of AX/BX), we do a kludge to see | |
42 | * if CX/DX have been changed in the e801 call and if so use AX/BX . | |
43 | * Michael Miller, April 2001 <michaelm@mjmm.org> | |
44 | * | |
45 | * Added long mode checking and SSE force. March 2003, Andi Kleen. | |
46 | */ | |
47 | ||
1da177e4 | 48 | #include <asm/segment.h> |
63104eec | 49 | #include <linux/utsrelease.h> |
1da177e4 LT |
50 | #include <linux/compile.h> |
51 | #include <asm/boot.h> | |
52 | #include <asm/e820.h> | |
53 | #include <asm/page.h> | |
54 | ||
55 | /* Signature words to ensure LILO loaded us right */ | |
56 | #define SIG1 0xAA55 | |
57 | #define SIG2 0x5A5A | |
58 | ||
59 | INITSEG = DEF_INITSEG # 0x9000, we move boot here, out of the way | |
60 | SYSSEG = DEF_SYSSEG # 0x1000, system loaded at 0x10000 (65536). | |
61 | SETUPSEG = DEF_SETUPSEG # 0x9020, this is the current segment | |
62 | # ... and the former contents of CS | |
63 | ||
64 | DELTA_INITSEG = SETUPSEG - INITSEG # 0x0020 | |
65 | ||
66 | .code16 | |
67 | .globl begtext, begdata, begbss, endtext, enddata, endbss | |
68 | ||
69 | .text | |
70 | begtext: | |
71 | .data | |
72 | begdata: | |
73 | .bss | |
74 | begbss: | |
75 | .text | |
76 | ||
77 | start: | |
78 | jmp trampoline | |
79 | ||
80 | # This is the setup header, and it must start at %cs:2 (old 0x9020:2) | |
81 | ||
82 | .ascii "HdrS" # header signature | |
8035d3ea | 83 | .word 0x0205 # header version number (>= 0x0105) |
1da177e4 LT |
84 | # or else old loadlin-1.5 will fail) |
85 | realmode_swtch: .word 0, 0 # default_switch, SETUPSEG | |
86 | start_sys_seg: .word SYSSEG | |
87 | .word kernel_version # pointing to kernel version string | |
88 | # above section of header is compatible | |
89 | # with loadlin-1.5 (header v1.5). Don't | |
90 | # change it. | |
91 | ||
92 | type_of_loader: .byte 0 # = 0, old one (LILO, Loadlin, | |
93 | # Bootlin, SYSLX, bootsect...) | |
94 | # See Documentation/i386/boot.txt for | |
95 | # assigned ids | |
96 | ||
97 | # flags, unused bits must be zero (RFU) bit within loadflags | |
98 | loadflags: | |
99 | LOADED_HIGH = 1 # If set, the kernel is loaded high | |
100 | CAN_USE_HEAP = 0x80 # If set, the loader also has set | |
101 | # heap_end_ptr to tell how much | |
102 | # space behind setup.S can be used for | |
103 | # heap purposes. | |
104 | # Only the loader knows what is free | |
105 | #ifndef __BIG_KERNEL__ | |
106 | .byte 0 | |
107 | #else | |
108 | .byte LOADED_HIGH | |
109 | #endif | |
110 | ||
111 | setup_move_size: .word 0x8000 # size to move, when setup is not | |
112 | # loaded at 0x90000. We will move setup | |
113 | # to 0x90000 then just before jumping | |
114 | # into the kernel. However, only the | |
115 | # loader knows how much data behind | |
116 | # us also needs to be loaded. | |
117 | ||
118 | code32_start: # here loaders can put a different | |
119 | # start address for 32-bit code. | |
120 | #ifndef __BIG_KERNEL__ | |
121 | .long 0x1000 # 0x1000 = default for zImage | |
122 | #else | |
123 | .long 0x100000 # 0x100000 = default for big kernel | |
124 | #endif | |
125 | ||
126 | ramdisk_image: .long 0 # address of loaded ramdisk image | |
127 | # Here the loader puts the 32-bit | |
128 | # address where it loaded the image. | |
129 | # This only will be read by the kernel. | |
130 | ||
131 | ramdisk_size: .long 0 # its size in bytes | |
132 | ||
133 | bootsect_kludge: | |
134 | .long 0 # obsolete | |
135 | ||
136 | heap_end_ptr: .word modelist+1024 # (Header version 0x0201 or later) | |
137 | # space from here (exclusive) down to | |
138 | # end of setup code can be used by setup | |
139 | # for local heap purposes. | |
140 | ||
141 | pad1: .word 0 | |
142 | cmd_line_ptr: .long 0 # (Header version 0x0202 or later) | |
143 | # If nonzero, a 32-bit pointer | |
144 | # to the kernel command line. | |
145 | # The command line should be | |
146 | # located between the start of | |
147 | # setup and the end of low | |
148 | # memory (0xa0000), or it may | |
149 | # get overwritten before it | |
150 | # gets read. If this field is | |
151 | # used, there is no longer | |
152 | # anything magical about the | |
153 | # 0x90000 segment; the setup | |
154 | # can be located anywhere in | |
155 | # low memory 0x10000 or higher. | |
156 | ||
157 | ramdisk_max: .long 0xffffffff | |
8035d3ea VG |
158 | kernel_alignment: .long 0x200000 # physical addr alignment required for |
159 | # protected mode relocatable kernel | |
160 | #ifdef CONFIG_RELOCATABLE | |
161 | relocatable_kernel: .byte 1 | |
162 | #else | |
163 | relocatable_kernel: .byte 0 | |
164 | #endif | |
165 | pad2: .byte 0 | |
166 | pad3: .word 0 | |
167 | ||
1da177e4 LT |
168 | trampoline: call start_of_setup |
169 | .align 16 | |
170 | # The offset at this point is 0x240 | |
f9ba7053 | 171 | .space (0xeff-0x240+1) # E820 & EDD space (ending at 0xeff) |
1da177e4 LT |
172 | # End of setup header ##################################################### |
173 | ||
174 | start_of_setup: | |
175 | # Bootlin depends on this being done early | |
176 | movw $0x01500, %ax | |
177 | movb $0x81, %dl | |
178 | int $0x13 | |
179 | ||
180 | #ifdef SAFE_RESET_DISK_CONTROLLER | |
181 | # Reset the disk controller. | |
182 | movw $0x0000, %ax | |
183 | movb $0x80, %dl | |
184 | int $0x13 | |
185 | #endif | |
186 | ||
187 | # Set %ds = %cs, we know that SETUPSEG = %cs at this point | |
188 | movw %cs, %ax # aka SETUPSEG | |
189 | movw %ax, %ds | |
190 | # Check signature at end of setup | |
191 | cmpw $SIG1, setup_sig1 | |
192 | jne bad_sig | |
193 | ||
194 | cmpw $SIG2, setup_sig2 | |
195 | jne bad_sig | |
196 | ||
197 | jmp good_sig1 | |
198 | ||
199 | # Routine to print asciiz string at ds:si | |
200 | prtstr: | |
201 | lodsb | |
202 | andb %al, %al | |
203 | jz fin | |
204 | ||
205 | call prtchr | |
206 | jmp prtstr | |
207 | ||
208 | fin: ret | |
209 | ||
210 | # Space printing | |
211 | prtsp2: call prtspc # Print double space | |
212 | prtspc: movb $0x20, %al # Print single space (note: fall-thru) | |
213 | ||
214 | prtchr: | |
215 | pushw %ax | |
216 | pushw %cx | |
217 | movw $0007,%bx | |
218 | movw $0x01, %cx | |
219 | movb $0x0e, %ah | |
220 | int $0x10 | |
221 | popw %cx | |
222 | popw %ax | |
223 | ret | |
224 | ||
225 | beep: movb $0x07, %al | |
226 | jmp prtchr | |
227 | ||
228 | no_sig_mess: .string "No setup signature found ..." | |
229 | ||
230 | good_sig1: | |
231 | jmp good_sig | |
232 | ||
233 | # We now have to find the rest of the setup code/data | |
234 | bad_sig: | |
235 | movw %cs, %ax # SETUPSEG | |
236 | subw $DELTA_INITSEG, %ax # INITSEG | |
237 | movw %ax, %ds | |
238 | xorb %bh, %bh | |
239 | movb (497), %bl # get setup sect from bootsect | |
240 | subw $4, %bx # LILO loads 4 sectors of setup | |
241 | shlw $8, %bx # convert to words (1sect=2^8 words) | |
242 | movw %bx, %cx | |
243 | shrw $3, %bx # convert to segment | |
244 | addw $SYSSEG, %bx | |
245 | movw %bx, %cs:start_sys_seg | |
246 | # Move rest of setup code/data to here | |
247 | movw $2048, %di # four sectors loaded by LILO | |
248 | subw %si, %si | |
249 | movw %cs, %ax # aka SETUPSEG | |
250 | movw %ax, %es | |
251 | movw $SYSSEG, %ax | |
252 | movw %ax, %ds | |
253 | rep | |
254 | movsw | |
255 | movw %cs, %ax # aka SETUPSEG | |
256 | movw %ax, %ds | |
257 | cmpw $SIG1, setup_sig1 | |
258 | jne no_sig | |
259 | ||
260 | cmpw $SIG2, setup_sig2 | |
261 | jne no_sig | |
262 | ||
263 | jmp good_sig | |
264 | ||
265 | no_sig: | |
266 | lea no_sig_mess, %si | |
267 | call prtstr | |
268 | ||
269 | no_sig_loop: | |
270 | jmp no_sig_loop | |
271 | ||
272 | good_sig: | |
273 | movw %cs, %ax # aka SETUPSEG | |
274 | subw $DELTA_INITSEG, %ax # aka INITSEG | |
275 | movw %ax, %ds | |
276 | # Check if an old loader tries to load a big-kernel | |
277 | testb $LOADED_HIGH, %cs:loadflags # Do we have a big kernel? | |
278 | jz loader_ok # No, no danger for old loaders. | |
279 | ||
280 | cmpb $0, %cs:type_of_loader # Do we have a loader that | |
281 | # can deal with us? | |
282 | jnz loader_ok # Yes, continue. | |
283 | ||
284 | pushw %cs # No, we have an old loader, | |
285 | popw %ds # die. | |
286 | lea loader_panic_mess, %si | |
287 | call prtstr | |
288 | ||
289 | jmp no_sig_loop | |
290 | ||
291 | loader_panic_mess: .string "Wrong loader, giving up..." | |
292 | ||
293 | loader_ok: | |
294 | /* check for long mode. */ | |
295 | /* we have to do this before the VESA setup, otherwise the user | |
296 | can't see the error message. */ | |
297 | ||
298 | pushw %ds | |
299 | movw %cs,%ax | |
300 | movw %ax,%ds | |
301 | ||
302 | /* minimum CPUID flags for x86-64 */ | |
303 | /* see http://www.x86-64.org/lists/discuss/msg02971.html */ | |
304 | #define SSE_MASK ((1<<25)|(1<<26)) | |
305 | #define REQUIRED_MASK1 ((1<<0)|(1<<3)|(1<<4)|(1<<5)|(1<<6)|(1<<8)|\ | |
306 | (1<<13)|(1<<15)|(1<<24)) | |
307 | #define REQUIRED_MASK2 (1<<29) | |
308 | ||
309 | pushfl /* standard way to check for cpuid */ | |
310 | popl %eax | |
311 | movl %eax,%ebx | |
312 | xorl $0x200000,%eax | |
313 | pushl %eax | |
314 | popfl | |
315 | pushfl | |
316 | popl %eax | |
317 | cmpl %eax,%ebx | |
318 | jz no_longmode /* cpu has no cpuid */ | |
319 | movl $0x0,%eax | |
320 | cpuid | |
321 | cmpl $0x1,%eax | |
322 | jb no_longmode /* no cpuid 1 */ | |
323 | xor %di,%di | |
324 | cmpl $0x68747541,%ebx /* AuthenticAMD */ | |
325 | jnz noamd | |
326 | cmpl $0x69746e65,%edx | |
327 | jnz noamd | |
328 | cmpl $0x444d4163,%ecx | |
329 | jnz noamd | |
330 | mov $1,%di /* cpu is from AMD */ | |
331 | noamd: | |
332 | movl $0x1,%eax | |
333 | cpuid | |
334 | andl $REQUIRED_MASK1,%edx | |
335 | xorl $REQUIRED_MASK1,%edx | |
336 | jnz no_longmode | |
337 | movl $0x80000000,%eax | |
338 | cpuid | |
339 | cmpl $0x80000001,%eax | |
340 | jb no_longmode /* no extended cpuid */ | |
341 | movl $0x80000001,%eax | |
342 | cpuid | |
343 | andl $REQUIRED_MASK2,%edx | |
344 | xorl $REQUIRED_MASK2,%edx | |
345 | jnz no_longmode | |
346 | sse_test: | |
347 | movl $1,%eax | |
348 | cpuid | |
349 | andl $SSE_MASK,%edx | |
350 | cmpl $SSE_MASK,%edx | |
351 | je sse_ok | |
352 | test %di,%di | |
353 | jz no_longmode /* only try to force SSE on AMD */ | |
354 | movl $0xc0010015,%ecx /* HWCR */ | |
355 | rdmsr | |
356 | btr $15,%eax /* enable SSE */ | |
357 | wrmsr | |
358 | xor %di,%di /* don't loop */ | |
359 | jmp sse_test /* try again */ | |
360 | no_longmode: | |
361 | call beep | |
362 | lea long_mode_panic,%si | |
363 | call prtstr | |
364 | no_longmode_loop: | |
365 | jmp no_longmode_loop | |
366 | long_mode_panic: | |
367 | .string "Your CPU does not support long mode. Use a 32bit distribution." | |
368 | .byte 0 | |
369 | ||
370 | sse_ok: | |
371 | popw %ds | |
372 | ||
373 | # tell BIOS we want to go to long mode | |
374 | movl $0xec00,%eax # declare target operating mode | |
375 | movl $2,%ebx # long mode | |
376 | int $0x15 | |
377 | ||
378 | # Get memory size (extended mem, kB) | |
379 | ||
380 | xorl %eax, %eax | |
381 | movl %eax, (0x1e0) | |
382 | #ifndef STANDARD_MEMORY_BIOS_CALL | |
383 | movb %al, (E820NR) | |
384 | # Try three different memory detection schemes. First, try | |
385 | # e820h, which lets us assemble a memory map, then try e801h, | |
386 | # which returns a 32-bit memory size, and finally 88h, which | |
387 | # returns 0-64m | |
388 | ||
389 | # method E820H: | |
390 | # the memory map from hell. e820h returns memory classified into | |
391 | # a whole bunch of different types, and allows memory holes and | |
392 | # everything. We scan through this memory map and build a list | |
393 | # of the first 32 memory areas, which we return at [E820MAP]. | |
f4549448 | 394 | # This is documented at http://www.acpi.info/, in the ACPI 2.0 specification. |
1da177e4 LT |
395 | |
396 | #define SMAP 0x534d4150 | |
397 | ||
398 | meme820: | |
399 | xorl %ebx, %ebx # continuation counter | |
400 | movw $E820MAP, %di # point into the whitelist | |
401 | # so we can have the bios | |
402 | # directly write into it. | |
403 | ||
404 | jmpe820: | |
405 | movl $0x0000e820, %eax # e820, upper word zeroed | |
406 | movl $SMAP, %edx # ascii 'SMAP' | |
407 | movl $20, %ecx # size of the e820rec | |
408 | pushw %ds # data record. | |
409 | popw %es | |
410 | int $0x15 # make the call | |
411 | jc bail820 # fall to e801 if it fails | |
412 | ||
413 | cmpl $SMAP, %eax # check the return is `SMAP' | |
414 | jne bail820 # fall to e801 if it fails | |
415 | ||
416 | # cmpl $1, 16(%di) # is this usable memory? | |
417 | # jne again820 | |
418 | ||
419 | # If this is usable memory, we save it by simply advancing %di by | |
420 | # sizeof(e820rec). | |
421 | # | |
422 | good820: | |
f9ba7053 | 423 | movb (E820NR), %al # up to 128 entries |
1da177e4 | 424 | cmpb $E820MAX, %al |
f9ba7053 | 425 | jae bail820 |
1da177e4 LT |
426 | |
427 | incb (E820NR) | |
428 | movw %di, %ax | |
429 | addw $20, %ax | |
430 | movw %ax, %di | |
431 | again820: | |
432 | cmpl $0, %ebx # check to see if | |
433 | jne jmpe820 # %ebx is set to EOF | |
434 | bail820: | |
435 | ||
436 | ||
437 | # method E801H: | |
438 | # memory size is in 1k chunksizes, to avoid confusing loadlin. | |
439 | # we store the 0xe801 memory size in a completely different place, | |
440 | # because it will most likely be longer than 16 bits. | |
441 | # (use 1e0 because that's what Larry Augustine uses in his | |
442 | # alternative new memory detection scheme, and it's sensible | |
443 | # to write everything into the same place.) | |
444 | ||
445 | meme801: | |
446 | stc # fix to work around buggy | |
f4549448 | 447 | xorw %cx,%cx # BIOSes which don't clear/set |
1da177e4 LT |
448 | xorw %dx,%dx # carry on pass/error of |
449 | # e801h memory size call | |
450 | # or merely pass cx,dx though | |
451 | # without changing them. | |
452 | movw $0xe801, %ax | |
453 | int $0x15 | |
454 | jc mem88 | |
455 | ||
456 | cmpw $0x0, %cx # Kludge to handle BIOSes | |
457 | jne e801usecxdx # which report their extended | |
458 | cmpw $0x0, %dx # memory in AX/BX rather than | |
459 | jne e801usecxdx # CX/DX. The spec I have read | |
460 | movw %ax, %cx # seems to indicate AX/BX | |
461 | movw %bx, %dx # are more reasonable anyway... | |
462 | ||
463 | e801usecxdx: | |
464 | andl $0xffff, %edx # clear sign extend | |
465 | shll $6, %edx # and go from 64k to 1k chunks | |
466 | movl %edx, (0x1e0) # store extended memory size | |
467 | andl $0xffff, %ecx # clear sign extend | |
468 | addl %ecx, (0x1e0) # and add lower memory into | |
469 | # total size. | |
470 | ||
471 | # Ye Olde Traditional Methode. Returns the memory size (up to 16mb or | |
472 | # 64mb, depending on the bios) in ax. | |
473 | mem88: | |
474 | ||
475 | #endif | |
476 | movb $0x88, %ah | |
477 | int $0x15 | |
478 | movw %ax, (2) | |
479 | ||
480 | # Set the keyboard repeat rate to the max | |
481 | movw $0x0305, %ax | |
482 | xorw %bx, %bx | |
483 | int $0x16 | |
484 | ||
485 | # Check for video adapter and its parameters and allow the | |
486 | # user to browse video modes. | |
487 | call video # NOTE: we need %ds pointing | |
488 | # to bootsector | |
489 | ||
490 | # Get hd0 data... | |
491 | xorw %ax, %ax | |
492 | movw %ax, %ds | |
493 | ldsw (4 * 0x41), %si | |
494 | movw %cs, %ax # aka SETUPSEG | |
495 | subw $DELTA_INITSEG, %ax # aka INITSEG | |
496 | pushw %ax | |
497 | movw %ax, %es | |
498 | movw $0x0080, %di | |
499 | movw $0x10, %cx | |
500 | pushw %cx | |
501 | cld | |
502 | rep | |
503 | movsb | |
504 | # Get hd1 data... | |
505 | xorw %ax, %ax | |
506 | movw %ax, %ds | |
507 | ldsw (4 * 0x46), %si | |
508 | popw %cx | |
509 | popw %es | |
510 | movw $0x0090, %di | |
511 | rep | |
512 | movsb | |
513 | # Check that there IS a hd1 :-) | |
514 | movw $0x01500, %ax | |
515 | movb $0x81, %dl | |
516 | int $0x13 | |
517 | jc no_disk1 | |
518 | ||
519 | cmpb $3, %ah | |
520 | je is_disk1 | |
521 | ||
522 | no_disk1: | |
523 | movw %cs, %ax # aka SETUPSEG | |
524 | subw $DELTA_INITSEG, %ax # aka INITSEG | |
525 | movw %ax, %es | |
526 | movw $0x0090, %di | |
527 | movw $0x10, %cx | |
528 | xorw %ax, %ax | |
529 | cld | |
530 | rep | |
531 | stosb | |
532 | is_disk1: | |
533 | ||
534 | # Check for PS/2 pointing device | |
535 | movw %cs, %ax # aka SETUPSEG | |
536 | subw $DELTA_INITSEG, %ax # aka INITSEG | |
537 | movw %ax, %ds | |
606bd58d | 538 | movb $0, (0x1ff) # default is no pointing device |
1da177e4 LT |
539 | int $0x11 # int 0x11: equipment list |
540 | testb $0x04, %al # check if mouse installed | |
541 | jz no_psmouse | |
542 | ||
606bd58d | 543 | movb $0xAA, (0x1ff) # device present |
1da177e4 LT |
544 | no_psmouse: |
545 | ||
546 | #include "../../i386/boot/edd.S" | |
547 | ||
548 | # Now we want to move to protected mode ... | |
549 | cmpw $0, %cs:realmode_swtch | |
550 | jz rmodeswtch_normal | |
551 | ||
552 | lcall *%cs:realmode_swtch | |
553 | ||
554 | jmp rmodeswtch_end | |
555 | ||
556 | rmodeswtch_normal: | |
557 | pushw %cs | |
558 | call default_switch | |
559 | ||
560 | rmodeswtch_end: | |
561 | # we get the code32 start address and modify the below 'jmpi' | |
562 | # (loader may have changed it) | |
563 | movl %cs:code32_start, %eax | |
564 | movl %eax, %cs:code32 | |
565 | ||
566 | # Now we move the system to its rightful place ... but we check if we have a | |
567 | # big-kernel. In that case we *must* not move it ... | |
568 | testb $LOADED_HIGH, %cs:loadflags | |
569 | jz do_move0 # .. then we have a normal low | |
570 | # loaded zImage | |
571 | # .. or else we have a high | |
572 | # loaded bzImage | |
573 | jmp end_move # ... and we skip moving | |
574 | ||
575 | do_move0: | |
576 | movw $0x100, %ax # start of destination segment | |
577 | movw %cs, %bp # aka SETUPSEG | |
578 | subw $DELTA_INITSEG, %bp # aka INITSEG | |
579 | movw %cs:start_sys_seg, %bx # start of source segment | |
580 | cld | |
581 | do_move: | |
582 | movw %ax, %es # destination segment | |
583 | incb %ah # instead of add ax,#0x100 | |
584 | movw %bx, %ds # source segment | |
585 | addw $0x100, %bx | |
586 | subw %di, %di | |
587 | subw %si, %si | |
588 | movw $0x800, %cx | |
589 | rep | |
590 | movsw | |
591 | cmpw %bp, %bx # assume start_sys_seg > 0x200, | |
592 | # so we will perhaps read one | |
593 | # page more than needed, but | |
594 | # never overwrite INITSEG | |
595 | # because destination is a | |
596 | # minimum one page below source | |
597 | jb do_move | |
598 | ||
599 | end_move: | |
600 | # then we load the segment descriptors | |
601 | movw %cs, %ax # aka SETUPSEG | |
602 | movw %ax, %ds | |
603 | ||
604 | # Check whether we need to be downward compatible with version <=201 | |
605 | cmpl $0, cmd_line_ptr | |
606 | jne end_move_self # loader uses version >=202 features | |
607 | cmpb $0x20, type_of_loader | |
608 | je end_move_self # bootsect loader, we know of it | |
609 | ||
610 | # Boot loader doesnt support boot protocol version 2.02. | |
611 | # If we have our code not at 0x90000, we need to move it there now. | |
612 | # We also then need to move the params behind it (commandline) | |
613 | # Because we would overwrite the code on the current IP, we move | |
614 | # it in two steps, jumping high after the first one. | |
615 | movw %cs, %ax | |
616 | cmpw $SETUPSEG, %ax | |
617 | je end_move_self | |
618 | ||
619 | cli # make sure we really have | |
620 | # interrupts disabled ! | |
621 | # because after this the stack | |
622 | # should not be used | |
623 | subw $DELTA_INITSEG, %ax # aka INITSEG | |
624 | movw %ss, %dx | |
625 | cmpw %ax, %dx | |
626 | jb move_self_1 | |
627 | ||
628 | addw $INITSEG, %dx | |
629 | subw %ax, %dx # this will go into %ss after | |
630 | # the move | |
631 | move_self_1: | |
632 | movw %ax, %ds | |
633 | movw $INITSEG, %ax # real INITSEG | |
634 | movw %ax, %es | |
635 | movw %cs:setup_move_size, %cx | |
636 | std # we have to move up, so we use | |
637 | # direction down because the | |
638 | # areas may overlap | |
639 | movw %cx, %di | |
640 | decw %di | |
641 | movw %di, %si | |
642 | subw $move_self_here+0x200, %cx | |
643 | rep | |
644 | movsb | |
645 | ljmp $SETUPSEG, $move_self_here | |
646 | ||
647 | move_self_here: | |
648 | movw $move_self_here+0x200, %cx | |
649 | rep | |
650 | movsb | |
651 | movw $SETUPSEG, %ax | |
652 | movw %ax, %ds | |
653 | movw %dx, %ss | |
654 | end_move_self: # now we are at the right place | |
655 | lidt idt_48 # load idt with 0,0 | |
656 | xorl %eax, %eax # Compute gdt_base | |
657 | movw %ds, %ax # (Convert %ds:gdt to a linear ptr) | |
658 | shll $4, %eax | |
659 | addl $gdt, %eax | |
660 | movl %eax, (gdt_48+2) | |
661 | lgdt gdt_48 # load gdt with whatever is | |
662 | # appropriate | |
663 | ||
664 | # that was painless, now we enable a20 | |
665 | call empty_8042 | |
666 | ||
667 | movb $0xD1, %al # command write | |
668 | outb %al, $0x64 | |
669 | call empty_8042 | |
670 | ||
671 | movb $0xDF, %al # A20 on | |
672 | outb %al, $0x60 | |
673 | call empty_8042 | |
674 | ||
675 | # | |
676 | # You must preserve the other bits here. Otherwise embarrasing things | |
677 | # like laptops powering off on boot happen. Corrected version by Kira | |
678 | # Brown from Linux 2.2 | |
679 | # | |
680 | inb $0x92, %al # | |
681 | orb $02, %al # "fast A20" version | |
682 | outb %al, $0x92 # some chips have only this | |
683 | ||
684 | # wait until a20 really *is* enabled; it can take a fair amount of | |
685 | # time on certain systems; Toshiba Tecras are known to have this | |
686 | # problem. The memory location used here (0x200) is the int 0x80 | |
687 | # vector, which should be safe to use. | |
688 | ||
689 | xorw %ax, %ax # segment 0x0000 | |
690 | movw %ax, %fs | |
691 | decw %ax # segment 0xffff (HMA) | |
692 | movw %ax, %gs | |
693 | a20_wait: | |
694 | incw %ax # unused memory location <0xfff0 | |
695 | movw %ax, %fs:(0x200) # we use the "int 0x80" vector | |
696 | cmpw %gs:(0x210), %ax # and its corresponding HMA addr | |
697 | je a20_wait # loop until no longer aliased | |
698 | ||
699 | # make sure any possible coprocessor is properly reset.. | |
700 | xorw %ax, %ax | |
701 | outb %al, $0xf0 | |
702 | call delay | |
703 | ||
704 | outb %al, $0xf1 | |
705 | call delay | |
706 | ||
707 | # well, that went ok, I hope. Now we mask all interrupts - the rest | |
708 | # is done in init_IRQ(). | |
709 | movb $0xFF, %al # mask all interrupts for now | |
710 | outb %al, $0xA1 | |
711 | call delay | |
712 | ||
713 | movb $0xFB, %al # mask all irq's but irq2 which | |
714 | outb %al, $0x21 # is cascaded | |
715 | ||
716 | # Well, that certainly wasn't fun :-(. Hopefully it works, and we don't | |
717 | # need no steenking BIOS anyway (except for the initial loading :-). | |
718 | # The BIOS-routine wants lots of unnecessary data, and it's less | |
719 | # "interesting" anyway. This is how REAL programmers do it. | |
720 | # | |
721 | # Well, now's the time to actually move into protected mode. To make | |
722 | # things as simple as possible, we do no register set-up or anything, | |
723 | # we let the gnu-compiled 32-bit programs do that. We just jump to | |
724 | # absolute address 0x1000 (or the loader supplied one), | |
725 | # in 32-bit protected mode. | |
726 | # | |
727 | # Note that the short jump isn't strictly needed, although there are | |
728 | # reasons why it might be a good idea. It won't hurt in any case. | |
729 | movw $1, %ax # protected mode (PE) bit | |
730 | lmsw %ax # This is it! | |
731 | jmp flush_instr | |
732 | ||
733 | flush_instr: | |
734 | xorw %bx, %bx # Flag to indicate a boot | |
735 | xorl %esi, %esi # Pointer to real-mode code | |
736 | movw %cs, %si | |
737 | subw $DELTA_INITSEG, %si | |
738 | shll $4, %esi # Convert to 32-bit pointer | |
739 | # NOTE: For high loaded big kernels we need a | |
740 | # jmpi 0x100000,__KERNEL_CS | |
741 | # | |
742 | # but we yet haven't reloaded the CS register, so the default size | |
743 | # of the target offset still is 16 bit. | |
f4549448 | 744 | # However, using an operand prefix (0x66), the CPU will properly |
1da177e4 LT |
745 | # take our 48 bit far pointer. (INTeL 80386 Programmer's Reference |
746 | # Manual, Mixing 16-bit and 32-bit code, page 16-6) | |
747 | ||
748 | .byte 0x66, 0xea # prefix + jmpi-opcode | |
749 | code32: .long 0x1000 # will be set to 0x100000 | |
750 | # for big kernels | |
751 | .word __KERNEL_CS | |
752 | ||
753 | # Here's a bunch of information about your current kernel.. | |
754 | kernel_version: .ascii UTS_RELEASE | |
755 | .ascii " (" | |
756 | .ascii LINUX_COMPILE_BY | |
757 | .ascii "@" | |
758 | .ascii LINUX_COMPILE_HOST | |
759 | .ascii ") " | |
760 | .ascii UTS_VERSION | |
761 | .byte 0 | |
762 | ||
763 | # This is the default real mode switch routine. | |
764 | # to be called just before protected mode transition | |
765 | default_switch: | |
766 | cli # no interrupts allowed ! | |
767 | movb $0x80, %al # disable NMI for bootup | |
768 | # sequence | |
769 | outb %al, $0x70 | |
770 | lret | |
771 | ||
772 | ||
773 | # This routine checks that the keyboard command queue is empty | |
774 | # (after emptying the output buffers) | |
775 | # | |
776 | # Some machines have delusions that the keyboard buffer is always full | |
777 | # with no keyboard attached... | |
778 | # | |
779 | # If there is no keyboard controller, we will usually get 0xff | |
780 | # to all the reads. With each IO taking a microsecond and | |
781 | # a timeout of 100,000 iterations, this can take about half a | |
782 | # second ("delay" == outb to port 0x80). That should be ok, | |
783 | # and should also be plenty of time for a real keyboard controller | |
784 | # to empty. | |
785 | # | |
786 | ||
787 | empty_8042: | |
788 | pushl %ecx | |
789 | movl $100000, %ecx | |
790 | ||
791 | empty_8042_loop: | |
792 | decl %ecx | |
793 | jz empty_8042_end_loop | |
794 | ||
795 | call delay | |
796 | ||
797 | inb $0x64, %al # 8042 status port | |
798 | testb $1, %al # output buffer? | |
799 | jz no_output | |
800 | ||
801 | call delay | |
802 | inb $0x60, %al # read it | |
803 | jmp empty_8042_loop | |
804 | ||
805 | no_output: | |
806 | testb $2, %al # is input buffer full? | |
807 | jnz empty_8042_loop # yes - loop | |
808 | empty_8042_end_loop: | |
809 | popl %ecx | |
810 | ret | |
811 | ||
812 | # Read the cmos clock. Return the seconds in al | |
813 | gettime: | |
814 | pushw %cx | |
815 | movb $0x02, %ah | |
816 | int $0x1a | |
817 | movb %dh, %al # %dh contains the seconds | |
818 | andb $0x0f, %al | |
819 | movb %dh, %ah | |
820 | movb $0x04, %cl | |
821 | shrb %cl, %ah | |
822 | aad | |
823 | popw %cx | |
824 | ret | |
825 | ||
826 | # Delay is needed after doing I/O | |
827 | delay: | |
828 | outb %al,$0x80 | |
829 | ret | |
830 | ||
831 | # Descriptor tables | |
832 | gdt: | |
833 | .word 0, 0, 0, 0 # dummy | |
834 | ||
835 | .word 0, 0, 0, 0 # unused | |
836 | ||
837 | .word 0xFFFF # 4Gb - (0x100000*0x1000 = 4Gb) | |
838 | .word 0 # base address = 0 | |
839 | .word 0x9A00 # code read/exec | |
840 | .word 0x00CF # granularity = 4096, 386 | |
841 | # (+5th nibble of limit) | |
842 | ||
843 | .word 0xFFFF # 4Gb - (0x100000*0x1000 = 4Gb) | |
844 | .word 0 # base address = 0 | |
845 | .word 0x9200 # data read/write | |
846 | .word 0x00CF # granularity = 4096, 386 | |
847 | # (+5th nibble of limit) | |
51d67a48 | 848 | gdt_end: |
1da177e4 LT |
849 | idt_48: |
850 | .word 0 # idt limit = 0 | |
851 | .word 0, 0 # idt base = 0L | |
852 | gdt_48: | |
51d67a48 | 853 | .word gdt_end-gdt-1 # gdt limit |
1da177e4 LT |
854 | .word 0, 0 # gdt base (filled in later) |
855 | ||
856 | # Include video setup & detection code | |
857 | ||
858 | #include "video.S" | |
859 | ||
860 | # Setup signature -- must be last | |
861 | setup_sig1: .word SIG1 | |
862 | setup_sig2: .word SIG2 | |
863 | ||
864 | # After this point, there is some free space which is used by the video mode | |
865 | # handling code to store the temporary mode table (not used by the kernel). | |
866 | ||
867 | modelist: | |
868 | ||
869 | .text | |
870 | endtext: | |
871 | .data | |
872 | enddata: | |
873 | .bss | |
874 | endbss: |