disklabel64 UFS+HAMMER boot support (was previously just HAMMER boot support)
[dragonfly.git] / sys / boot / pc32 / boot2 / boot1.S
CommitLineData
409cbc03 1/*
cacaceec
MD
2 * Copyright (c) 2003,2004 The DragonFly Project. All rights reserved.
3 *
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
16 * distribution.
17 * 3. Neither the name of The DragonFly Project nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific, prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
409cbc03
MD
34 * Copyright (c) 1998 Robert Nordier
35 * All rights reserved.
36 *
37 * Redistribution and use in source and binary forms are freely
38 * permitted provided that the above copyright notice and this
39 * paragraph and the following disclaimer are duplicated in all
40 * such forms.
41 *
42 * This software is provided "AS IS" and without any express or
43 * implied warranties, including, without limitation, the implied
44 * warranties of merchantability and fitness for a particular
45 * purpose.
46 *
47 * $FreeBSD: src/sys/boot/i386/boot2/boot1.s,v 1.23 2003/08/22 01:59:28 imp Exp $
7580e818 48 * $DragonFly: src/sys/boot/pc32/boot2/boot1.S,v 1.10 2008/09/13 11:45:45 corecode Exp $
409cbc03 49 */
984263bc 50
409cbc03 51#include "../bootasm.h"
984263bc 52
5ee58eed
MD
53// Partition Constants
54 .set PRT_OFF,0x1be // Partition offset
55 .set PRT_NUM,0x4 // Partitions
56 .set PRT_BSD,0xa5 // Partition type
984263bc 57
5ee58eed
MD
58// Flag Bits
59 .set FL_PACKET,0x80 // Packet mode
984263bc 60
5ee58eed
MD
61// Misc. Constants
62 .set SIZ_PAG,0x1000 // Page size
63 .set SIZ_SEC,0x200 // Sector size
7580e818 64#ifndef NSECT
5ee58eed 65 .set NSECT,0x10
7580e818 66#endif
409cbc03 67
984263bc
MD
68 .globl start
69 .globl xread
70 .code16
71
5ee58eed 72start: jmp main // Start recognizably
984263bc 73
5ee58eed
MD
74// This is the start of a standard BIOS Parameter Block (BPB). Most bootable
75// FAT disks have this at the start of their MBR. While normal BIOS's will
76// work fine without this section, IBM's El Torito emulation "fixes" up the
77// BPB by writing into the memory copy of the MBR. Rather than have data
78// written into our xread routine, we'll define a BPB to work around it.
79// The data marked with (T) indicates a field required for a ThinkPad to
80// recognize the disk and (W) indicates fields written from IBM BIOS code.
81// The use of the BPB is based on what OpenBSD and NetBSD implemented in
82// their boot code but the required fields were determined by trial and error.
83//
84// Note: If additional space is needed in boot1, one solution would be to
85// move the "prompt" message data (below) to replace the OEM ID.
984263bc
MD
86
87 .org 0x03, 0x00
5ee58eed 88oemid: .space 0x08, 0x00 // OEM ID
984263bc
MD
89
90 .org 0x0b, 0x00
5ee58eed
MD
91bpb: .word 512 // sector size (T)
92 .byte 0 // sectors/clustor
93 .word 0 // reserved sectors
94 .byte 0 // number of FATs
95 .word 0 // root entries
96 .word 0 // small sectors
97 .byte 0 // media type (W)
98 .word 0 // sectors/fat
99 .word 18 // sectors per track (T)
100 .word 2 // number of heads (T)
101 .long 0 // hidden sectors (W)
102 .long 0 // large sectors
984263bc
MD
103
104 .org 0x24, 0x00
5ee58eed 105ebpb: .byte 0 // BIOS physical drive number (W)
984263bc
MD
106
107 .org 0x25,0x90
5ee58eed
MD
108//
109// Trampoline used by boot2 to call read to read data from the disk via
110// the BIOS. Call with:
111//
112// %cx:%ax - long - LBA to read in
113// %es:(%bx) - caddr_t - buffer to read data into
114// %dl - byte - drive to read from
115// %dh - byte - num sectors to read
116//
984263bc 117
5ee58eed
MD
118xread: push %ss // Address
119 pop %ds // data
120//
121// Setup an EDD disk packet and pass it to read
122//
123xread.1: // Starting
124 pushl $0x0 // absolute
125 push %cx // block
126 push %ax // number
127 push %es // Address of
128 push %bx // transfer buffer
129 xor %ax,%ax // Number of
130 movb %dh,%al // blocks to
131 push %ax // transfer
132 push $0x10 // Size of packet
133 mov %sp,%bp // Packet pointer
134 callw read // Read from disk
135 lea 0x10(%bp),%sp // Clear stack
136 lret // To far caller
137//
138// Load the rest of boot2 and BTX up, copy the parts to the right locations,
139// and start it all up.
140//
984263bc 141
5ee58eed
MD
142//
143// Setup the segment registers to flat addressing (segment 0) and setup the
144// stack to end just below the start of our code.
145//
76adb3c3
MD
146// XXX note - our origin (start) points to the MEM_BIOS_LADDR. We run
147// from there but boot2 later on calls xread at BOOT1_ORIGIN.
148//
5ee58eed
MD
149main: cld // String ops inc
150 xor %cx,%cx // Zero
151 mov %cx,%es // Address
152 mov %cx,%ds // data
153 mov %cx,%ss // Set up
154 mov $start,%sp // stack
155//
cacaceec
MD
156// Relocate ourself to BOOT1_ORIGIN. Since %cx == 0, the inc %ch sets
157// %cx == 0x100 (256 words == 512 bytes).
5ee58eed
MD
158//
159 mov %sp,%si // Source
cacaceec 160 mov $BOOT1_ORIGIN,%di // Destination
5ee58eed
MD
161 incb %ch // Word count
162 rep // Copy
163 movsw // code
164//
165// If we are on a hard drive, then load the MBR and look for the first
76adb3c3
MD
166// FreeBSD slice.
167//
168// Note, we can't use the fake partition entry (part4), as it may contain
169// garbage if this is a normal boot1 on a slice, verses a dangerously
170// dedicated disk. Hardwire sector 0 to acquire the MBR
5ee58eed 171//
76adb3c3
MD
172 xor %ax,%ax
173 xor %cx,%cx
5ee58eed
MD
174 cmpb $0x80,%dl // Hard drive?
175 jb main.4 // No
176 movb $0x1,%dh // Block count
76adb3c3 177 callw nread_alt // Read MBR
5ee58eed 178 mov $0x1,%cx // Two passes
04144d62 179main.1: mov $BOOT2_LOAD_BUF+PRT_OFF,%si // Partition table
5ee58eed
MD
180 movb $0x1,%dh // Partition
181main.2: cmpb $PRT_BSD,0x4(%si) // Our partition type?
182 jne main.3 // No
183 jcxz main.5 // If second pass
184 testb $0x80,(%si) // Active?
185 jnz main.5 // Yes
186main.3: add $0x10,%si // Next entry
187 incb %dh // Partition
188 cmpb $0x1+PRT_NUM,%dh // In table?
189 jb main.2 // Yes
190 dec %cx // Do two
191 jcxz main.1 // passes
192//
193// If we get here, we didn't find any FreeBSD slices at all, so print an
194// error message and die.
195//
196 mov $msg_part,%si // Message
197 jmp error // Error
198//
199// Floppies use partition 0 of drive 0.
200//
201main.4: xor %dx,%dx // Partition:drive
202//
203// Ok, we have a slice and drive in %dx now, so use that to locate and load
204// boot2. %si references the start of the slice we are looking for, so go
d64b2e33
MD
205// ahead and load up the first N sectors (boot1 + boot2) from that.
206//
207// N is 16 for boot1 in a disklabel32 and up to 32 in a disklabel64. The
208// disklabel64 can hold up to 64 sectors but MEM_BTX_USR+BOOT2_VORIGIN
209// will overflow the segment if we use more then 32 sectors.
04144d62
MD
210//
211// When we read it in, we conveniently use BOOT2_LOAD_BUF (0x8c00) as our
212// transfer buffer. Thus, boot1 ends up at 0x8c00, and boot2 starts at
213// 0x8c00 + 0x200 = 0x8e00.
214//
2d7f6790 215// The first part of boot2 is the disklabel, which is 0x200 bytes long.
5ee58eed
MD
216// The second part is BTX, which is thus loaded into 0x9000, which is where
217// it also runs from. The boot2.bin binary starts right after the end of
218// BTX, so we have to figure out where the start of it is and then move the
04144d62
MD
219// binary to 0xc000. Normally, BTX clients start at MEM_BTX_USR, or 0xa000,
220// but when we use btxld to create boot2, we use an entry point of 0x2000.
221// That entry point is relative to MEM_BTX_USR; thus boot2.bin starts
222// at 0xc000.
5ee58eed 223//
cacaceec
MD
224// MEM_BTX_USR_ARG will be overwritten by the disk read and the relocation
225// loop, so we must store the argument after completing said loops.
226//
227main.5: pushw %dx // Save args
5ee58eed 228 movb $NSECT,%dh // Sector count
6080181b
SS
229#ifdef DISKLABEL64
230 // In disklabel64 boot2 starts
231 addl $7,0x8(%si) // offset 0x1000.
232#endif
5ee58eed 233 callw nread // Read disk
4e06dda7
MD
234 mov $MEM_BTX_ORG,%bx // Base of BTX header
235 mov 0xa(%bx),%si // Get BTX text length (btx.S)
236 add %bx,%si // %si = start of boot2.bin
237 // %di = relocation target
238 mov $MEM_BTX_USR+BOOT2_VORIGIN,%di
239 mov $MEM_BTX_ORG+(NSECT-1)*SIZ_SEC,%cx
240 sub %si,%cx // %cx = Size of boot2 client
241 rep // Relocate boot2
242 movsb
cacaceec 243 popw MEM_BTX_USR_ARG // save (disk,slice) for boot2
4e06dda7
MD
244
245#if 0
246 // XXX DISABLED. This makes incorrect assumptions about
247 // where BSS begins, potentially leaving garbage in the BSS
248 // space. The BSS zeroing code has been moved to
249 // btx/lib/btxcsu.S (BTX client startup code) where we have
250 // more definitive knowledge about where BSS resides.
251 //
252 // %cx now contains 0. Calculate 0x[1]0000 - %di to get a
253 // count of assumed BSS bytes from the end of boot2.bin up
254 // to 0x10000, then zero it out.
255 //
256 sub %di,%cx
257 xorb %al,%al
258 rep
259 stosb
260#endif
5ee58eed 261 callw seta20 // Enable A20
cacaceec
MD
262
263 // YYY
264 pushw $MEM_BTX_ENTRY // Start BTX
265 retw
5ee58eed
MD
266//
267// Enable A20 so we can access memory above 1 meg.
268//
269seta20: cli // Disable interrupts
270seta20.1: inb $0x64,%al // Get status
271 testb $0x2,%al // Busy?
272 jnz seta20.1 // Yes
273 movb $0xd1,%al // Command: Write
274 outb %al,$0x64 // output port
275seta20.2: inb $0x64,%al // Get status
276 testb $0x2,%al // Busy?
277 jnz seta20.2 // Yes
278 movb $0xdf,%al // Enable
279 outb %al,$0x60 // A20
280 sti // Enable interrupts
281 retw // To caller
282//
283// Trampoline used to call read from within boot1.
284//
76adb3c3 285nread:
5ee58eed
MD
286 mov 0x8(%si),%ax // Get
287 mov 0xa(%si),%cx // LBA
76adb3c3
MD
288nread_alt:
289 mov $BOOT2_LOAD_BUF,%bx // Transfer buffer
5ee58eed
MD
290 push %cs // Read from
291 callw xread.1 // disk
292 jnc return // If success, return
293 mov $msg_read,%si // Otherwise, set the error
294 // message and fall through to
295 // the error routine
296//
297// Print out the error message pointed to by %ds:(%si) followed
298// by a prompt, wait for a keypress, and then reboot the machine.
299//
300error: callw putstr // Display message
301 mov $prompt,%si // Display
302 callw putstr // prompt
303 xorb %ah,%ah // BIOS: Get
304 int $0x16 // keypress
305 movw $0x1234, BDA_BOOT // Do a warm boot
306 ljmp $0xffff,$0x0 // reboot the machine
307//
308// Display a null-terminated string using the BIOS output.
309//
310putstr.0: mov $0x7,%bx // Page:attribute
311 movb $0xe,%ah // BIOS: Display
312 int $0x10 // character
313putstr: lodsb // Get char
314 testb %al,%al // End of string?
315 jne putstr.0 // No
984263bc 316
5ee58eed
MD
317//
318// Overused return code. ereturn is used to return an error from the
319// read function. Since we assume putstr succeeds, we (ab)use the
320// same code when we return from putstr.
321//
322ereturn: movb $0x1,%ah // Invalid
323 stc // argument
324return: retw // To caller
325//
326// Reads sectors from the disk. If EDD is enabled, then check if it is
327// installed and use it if it is. If it is not installed or not enabled, then
328// fall back to using CHS. Since we use a LBA, if we are using CHS, we have to
329// fetch the drive parameters from the BIOS and divide it out ourselves.
330// Call with:
331//
332// %dl - byte - drive number
333// stack - 10 bytes - EDD Packet
ed987dc9
MD
334
335read:
336 /*
337 * Try EDD mode first. If not enabled or no BIOS support
338 * exists, fall back to CHS mode.
339 */
340 testb $FL_PACKET,%cs:BOOT1_ORIGIN+flags-start
341 jz read.1
342
343 /*
344 * BIOS: check extensions present
345 */
346 mov $0x55aa,%bx
347 push %dx
348 movb $0x41,%ah
349 int $0x13
350 pop %dx
351 jc read.1 /* BIOS error return */
352 cmp $0xaa55,%bx /* check for proper magic */
353 jne read.1
354 testb $0x1,%cl /* packet interface support? */
355 jz read.1
356
357 /*
358 * Issue packet command.
359 * BIOS: Extended read command
360 */
361 mov %bp,%si
362 movb $0x42,%ah
363 int $0x13
364 retw
365
366 /*
367 * Fallback to CHS mode
368 */
369read.1:
370 push %dx // Save
5ee58eed
MD
371 movb $0x8,%ah // BIOS: Get drive
372 int $0x13 // parameters
373 movb %dh,%ch // Max head number
374 pop %dx // Restore
375 jc return // If error
376 andb $0x3f,%cl // Sectors per track
377 jz ereturn // If zero
378 cli // Disable interrupts
379 mov 0x8(%bp),%eax // Get LBA
380 push %dx // Save
381 movzbl %cl,%ebx // Divide by
382 xor %edx,%edx // sectors
383 div %ebx // per track
384 movb %ch,%bl // Max head number
385 movb %dl,%ch // Sector number
386 inc %bx // Divide by
387 xorb %dl,%dl // number
388 div %ebx // of heads
389 movb %dl,%bh // Head number
390 pop %dx // Restore
391 cmpl $0x3ff,%eax // Cylinder number supportable?
392 sti // Enable interrupts
ed987dc9 393 ja ereturn // No, failed
5ee58eed
MD
394 xchgb %al,%ah // Set up cylinder
395 rorb $0x2,%al // number
396 orb %ch,%al // Merge
397 inc %ax // sector
398 xchg %ax,%cx // number
399 movb %bh,%dh // Head number
400 subb %ah,%al // Sectors this track
401 mov 0x2(%bp),%ah // Blocks to read
402 cmpb %ah,%al // To read
403 jb read.2 // this
404#ifdef TRACK_AT_A_TIME
405 movb %ah,%al // track
406#else
407 movb $1,%al // one sector
408#endif
409read.2: mov $0x5,%di // Try count
410read.3: les 0x4(%bp),%bx // Transfer buffer
411 push %ax // Save
412 movb $0x2,%ah // BIOS: Read
413 int $0x13 // from disk
414 pop %bx // Restore
415 jnc read.4 // If success
416 dec %di // Retry?
417 jz read.6 // No
418 xorb %ah,%ah // BIOS: Reset
419 int $0x13 // disk system
420 xchg %bx,%ax // Block count
421 jmp read.3 // Continue
422read.4: movzbw %bl,%ax // Sectors read
423 add %ax,0x8(%bp) // Adjust
424 jnc read.5 // LBA,
425 incw 0xa(%bp) // transfer
426read.5: shlb %bl // buffer
427 add %bl,0x5(%bp) // pointer,
428 sub %al,0x2(%bp) // block count
ed987dc9 429 ja read.1 // If not done
5ee58eed 430read.6: retw // To caller
984263bc 431
5ee58eed 432// Messages
984263bc
MD
433
434msg_read: .asciz "Read"
435msg_part: .asciz "Boot"
436
437prompt: .asciz " error\r\n"
438
5ee58eed 439flags: .byte FLAGS // Flags
984263bc
MD
440
441 .org PRT_OFF,0x90
442
5ee58eed 443// Partition table
76adb3c3
MD
444//
445// THIS MAY NOT BE WRITTEN OUT TO THE BOOT1 AREA OF THE DISKLABEL. This
446// section is only written out when the disklabel is placed on the raw
447// disk instead of in a slice, when creating a dangerously dedicated disk.
984263bc
MD
448
449 .fill 0x30,0x1,0x0
450part4: .byte 0x80, 0x00, 0x01, 0x00
5ee58eed 451 .byte 0xa5, 0xfe, 0xff, 0xff
984263bc 452 .byte 0x00, 0x00, 0x00, 0x00
5ee58eed 453 .byte 0x50, 0xc3, 0x00, 0x00 // 50000 sectors long, bleh
984263bc 454
5ee58eed 455 .word 0xaa55 // Magic number