wok annotate linux-libre/stuff/linux-libre-header-2.6.37-gnu.u @ rev 18897

syslinux/isohybrid.exe add -r support
author Pascal Bellard <pascal.bellard@slitaz.org>
date Sun Feb 14 22:06:06 2016 +0100 (2016-02-14)
parents
children
rev   line source
pascal@14201 1 --- linux-2.6.30.6/arch/x86/boot/header.S
pascal@14201 2 +++ linux-2.6.30.6/arch/x86/boot/header.S
pascal@14201 3 @@ -6,7 +6,7 @@
pascal@14201 4 * Based on bootsect.S and setup.S
pascal@14201 5 * modified by more people than can be counted
pascal@14201 6 *
pascal@14201 7 - * Rewritten as a common file by H. Peter Anvin (Apr 2007)
pascal@14201 8 + * Rewritten Pascal Bellard (Nov 2009)
pascal@14201 9 *
pascal@14201 10 * BIG FAT NOTE: We're in real mode using 64k segments. Therefore segment
pascal@14201 11 * addresses must be multiplied by 16 to obtain their respective linear
pascal@14201 12 @@ -27,6 +27,8 @@
pascal@14201 13
pascal@14201 14 BOOTSEG = 0x07C0 /* original address of boot-sector */
pascal@14201 15 SYSSEG = 0x1000 /* historical load address >> 4 */
pascal@14201 16 +INITSEG = 0x9000 /* boot address >> 4 */
pascal@14201 17 +SETUPSEG = 0x9020 /* setup address >> 4 */
pascal@14201 18
pascal@14201 19 #ifndef SVGA_MODE
pascal@14201 20 #define SVGA_MODE ASK_VGA
pascal@14201 21 @@ -40,53 +42,412 @@
pascal@14201 22 #define ROOT_RDONLY 1
pascal@14201 23 #endif
pascal@14201 24
pascal@14201 25 +/* some extra features */
pascal@14201 26 +#define EDIT_CMDLINE on hotkey
pascal@14201 27 +#define SHOW_REGS show int13 status & parameters
pascal@14201 28 +
pascal@14201 29 .code16
pascal@14201 30 .section ".bstext", "ax"
pascal@14201 31
pascal@14201 32 .global bootsect_start
pascal@14201 33 bootsect_start:
pascal@14201 34 + cld # assume nothing
pascal@14201 35 +stacktop = 0x9E00 # in 0x8000 .. 0xA000
pascal@14201 36 +zeroed = 48+10 # gdt + zeroed registers
pascal@14201 37 + movw $stacktop-12-zeroed, %di # stacktop is an arbitrary value >=
pascal@14201 38 + # length of bootsect + length of
pascal@14201 39 + # setup + room for stack;
pascal@14201 40 + # 12 is disk parm size.
pascal@14201 41 + pushw $INITSEG
pascal@14201 42 + popw %es # %es = INITSEG
pascal@14201 43 +
pascal@14201 44 + pushw %es
pascal@14201 45 + popw %ss # %ss and %es already contain INITSEG
pascal@14201 46 + movw %di, %sp # put stack at INITSEG:stacktop-...
pascal@14201 47 +
pascal@14201 48 +# Many BIOS's default disk parameter tables will not recognize
pascal@14201 49 +# multi-sector reads beyond the maximum sector number specified
pascal@14201 50 +# in the default diskette parameter tables - this may mean 7
pascal@14201 51 +# sectors in some cases.
pascal@14201 52 +#
pascal@14201 53 +# Since single sector reads are slow and out of the question,
pascal@14201 54 +# we must take care of this by creating new parameter tables
pascal@14201 55 +# (for the first disk) in RAM. We can set the maximum sector
pascal@14201 56 +# count to 36 - the most we will encounter on an ED 2.88.
pascal@14201 57 +#
pascal@14201 58 +# High doesn't hurt. Low does. Let's use the max: 63
pascal@14201 59 +#
pascal@14201 60 +# Segments are as follows: %es = %ss = INITSEG,
pascal@14201 61 +
pascal@14201 62 + xorw %ax, %ax # %ax = 0
pascal@14201 63 + movw $zeroed/2, %cx # clear gdt + offset, %ds, limits
pascal@14201 64 + rep # don't worry about cld
pascal@14201 65 + stosw # already done above
pascal@14201 66 + popw %bx # offset = 0
pascal@14201 67 + popw %ds # %ds = 0
pascal@14201 68 + popw %gs # %gs = 0
pascal@14201 69 +
pascal@14201 70 + movb setup_sects+0x7C00, %al # read bootsector + setup (%ds = 0)
pascal@14201 71 + incw %ax
pascal@14201 72 +
pascal@14201 73 + pushw %es
pascal@14201 74 + pushw %di # %ds:%bx+0x78 is parameter table address
pascal@14201 75 + ldsw 0x78(%bx), %si # %ds:%si is source
pascal@14201 76 + movb $6, %cl # copy 12 bytes
pascal@14201 77 + rep # don't worry about cld
pascal@14201 78 + movsw # already done above
pascal@14201 79 + popl %gs:0x78(%bx) # update parameter table address
pascal@14201 80 + pushw %es
pascal@14201 81 + popw %ds # now %ds = %es = %ss = INITSEG
pascal@14201 82 + movb $63, 0x4-12(%di) # patch sector count, %di = stacktop
pascal@14201 83 + cli
pascal@14201 84 +
pascal@14201 85 + xchg %ax, %di # sector count
pascal@14201 86 + popw %ax # limits = 0
pascal@14201 87 + incw %cx # cylinder 0, sector 1
pascal@14201 88 + call read_first_sectors # read setup
pascal@14201 89 +
pascal@14201 90 +offset_version = 0xE
pascal@14201 91 + movw $0x200,%si
pascal@14201 92 + addw offset_version(%si),%si # starting protocol 2.00, Kernel 1.3.73
pascal@14201 93 + call putstr # show which kernel we are loading
pascal@14201 94 +
pascal@14201 95 +# The cmdline can be entered and modifed at boot time.
pascal@14201 96 +# Only characters before the cursor are passed to the kernel.
pascal@14201 97 + popw %bx # clear %bx
pascal@14201 98 + orw cmd_line_ptr, %bx
pascal@14201 99 + jz nocmdline
pascal@14201 100 + pushw %bx
pascal@14201 101 + incw %di
pascal@14201 102 + call read_sectors
pascal@14201 103 + popw %si
pascal@14201 104 + call putstr
pascal@14201 105 +#ifdef EDIT_CMDLINE
pascal@14201 106 +cmdlp:
pascal@14201 107 + movb $0x20, %al # clear end of line
pascal@14201 108 + int $0x10 # with Space
pascal@14201 109 + movb $8, %al # and BackSpace
pascal@14201 110 + int $0x10
pascal@14201 111 + decw %si
pascal@14201 112 +cmdget:
pascal@14201 113 + call wait4key
pascal@14201 114 + cmpb $8, %al # BackSpace ?
pascal@14201 115 + je cmdbs
pascal@14201 116 + movb %al, (%si) # store char
pascal@14201 117 + lodsw # %si += 2
pascal@14201 118 +cmdbs:
pascal@14201 119 +#if 1
pascal@14201 120 + cmpw %si,cmd_line_ptr
pascal@14201 121 + je cmdget
pascal@14201 122 +#endif
pascal@14201 123 + call putc # set %ah and %bx
pascal@14201 124 + cmpb $10, %al # Enter ?
pascal@14201 125 + jne cmdlp
pascal@14201 126 + movb %bh,-2(%si) # set end of string and remove CR
pascal@14201 127 +endcmdline:
pascal@14201 128 +#endif
pascal@14201 129 +nocmdline:
pascal@14201 130
pascal@14201 131 - # Normalize the start address
pascal@14201 132 - ljmp $BOOTSEG, $start2
pascal@14201 133 -
pascal@14201 134 -start2:
pascal@14201 135 - movw %cs, %ax
pascal@14201 136 - movw %ax, %ds
pascal@14201 137 - movw %ax, %es
pascal@14201 138 - movw %ax, %ss
pascal@14201 139 - xorw %sp, %sp
pascal@14201 140 - sti
pascal@14201 141 - cld
pascal@14201 142 -
pascal@14201 143 - movw $bugger_off_msg, %si
pascal@14201 144 +# This routine loads the system at address SYSSEG, making sure
pascal@14201 145 +# no 64kB boundaries are crossed. We try to load it as fast as
pascal@14201 146 +# possible, loading whole tracks whenever we can.
pascal@14201 147 +
pascal@14201 148 +ramdisk_image = 0x0218
pascal@14201 149 +ramdisk_size = 0x021C
pascal@14201 150 + movw %sp, %si # for bootsect_gdt
pascal@14201 151 + decw 16(%si) # bootsect_src = 64Kb
pascal@14201 152 + decw 24(%si) # bootsect_dst = 64Kb
pascal@14201 153 + movw $syssize, %di
pascal@14201 154 +type_of_loader = 0x210
pascal@14201 155 +loadflags = 0x211
pascal@14201 156 +heap_end_ptr = 0x224
pascal@14201 157 +ksyssize = 500
pascal@14201 158 + orw $0x80FF, type_of_loader-ksyssize(%di) # loader type = 0xFF
pascal@14201 159 + movw $stacktop-0x200, heap_end_ptr-ksyssize(%di)
pascal@14201 160 + movb $0x10, %al # destination = 0x100000
pascal@14201 161 + movb $5, %cl
pascal@14201 162 +initrdlp:
pascal@14201 163 + decw %ax
pascal@14201 164 + movb $0x93,%ah
pascal@14201 165 + movw %ax, 28(%si) # bootsect_dst_base+2
pascal@14201 166 + movb $(SYSSEG/4096), %al # source = SYSSEG
pascal@14201 167 + movw %ax, 20(%si) # bootsect_src_base+2
pascal@14201 168 + cbw
pascal@14201 169 + cwde
pascal@14201 170 + shlw %cl, %ax
pascal@14201 171 + decw %ax
pascal@14201 172 + addl (%di),%eax
pascal@14201 173 + shrl %cl, %eax
pascal@14201 174 +syslp:
pascal@14201 175 + pushw $SYSSEG
pascal@14201 176 + popw %es
pascal@14201 177 + movw $128,%di # 64Kb
pascal@14201 178 + subw %di, %ax # max 32M > int 15 limit
pascal@14201 179 + pushf
pascal@14201 180 + jnc not_last
pascal@14201 181 + addw %ax, %di
pascal@14201 182 +not_last:
pascal@14201 183 + xorw %bx, %bx # clear %bx
pascal@14201 184 + pushw %ax
pascal@14201 185 +#if defined(SHOW_REGS)
pascal@14201 186 + pushw %si
pascal@14201 187 + call read_sectors
pascal@14201 188 + popw %si
pascal@14201 189 +#else
pascal@14201 190 + call read_sectors
pascal@14201 191 +#endif
pascal@14201 192 + movw $0x8000, %cx # full 64K
pascal@14201 193 + movb $0x87, %ah
pascal@14201 194 + incb 28(%si) # bootsect_dst_base+2
pascal@14201 195 + int $0x15 # max 16M
pascal@14201 196 + popw %ax
pascal@14201 197 + popf
pascal@14201 198 + ja syslp
pascal@14201 199 + movw ramdisk_image+2,%ax
pascal@14201 200 + movw $ramdisk_size,%di
pascal@14201 201 + movb $9, %cl
pascal@14201 202 + cmpb %al,28(%si)
pascal@14201 203 + jb initrdlp
pascal@14201 204 +
pascal@14201 205 +# This procedure turns off the floppy drive motor, so
pascal@14201 206 +# that we enter the kernel in a known state, and
pascal@14201 207 +# don't have to worry about it later.
pascal@14201 208 +
pascal@14201 209 +#if 1
pascal@14201 210 +kill_motor:
pascal@14201 211 + xchgw %ax, %bx # reset FDC
pascal@14201 212 + int $0x13
pascal@14201 213 +#else
pascal@14201 214 +kill_motor:
pascal@14201 215 + movw $0x3f2, %dx
pascal@14201 216 + xchgw %ax, %bx
pascal@14201 217 + outb %al, %dx
pascal@14201 218 +#endif
pascal@14201 219
pascal@14201 220 -msg_loop:
pascal@14201 221 - lodsb
pascal@14201 222 - andb %al, %al
pascal@14201 223 - jz bs_die
pascal@14201 224 - movb $0xe, %ah
pascal@14201 225 - movw $7, %bx
pascal@14201 226 +# After that (everything loaded), we jump to the setup-routine
pascal@14201 227 +# loaded directly after the bootblock:
pascal@14201 228 +# Segments are as follows: %ds = %ss = INITSEG
pascal@14201 229 +
pascal@14201 230 + ljmp $SETUPSEG, $0
pascal@14201 231 +
pascal@14201 232 +# read_sectors reads %di sectors into %es:0 buffer.
pascal@14201 233 +# %es:0 is updated to the next memory location.
pascal@14201 234 +# First, sectors are read sector by sector until
pascal@14201 235 +# sector per track count is known. Then they are
pascal@14201 236 +# read track by track.
pascal@14201 237 +# Assume no error on first track.
pascal@14201 238 +
pascal@14201 239 +#define FLOPPY_CYLINDERS 80 /* 80 cylinders minimum */
pascal@14201 240 +#define FLOPPY_HEADS 2 /* 2 heads minimum */
pascal@14201 241 +#define FLOPPY_SECTORS 18 /* 18 sectors minimum */
pascal@14201 242 +
pascal@14201 243 +#ifdef SHOW_REGS
pascal@14201 244 +print_loop:
pascal@14201 245 + movb $0x6 + 'A' - 1, %al
pascal@14201 246 + subb %cl, %al
pascal@14201 247 + movw $regs, %si # caller %si is saved
pascal@14201 248 + call putcs # putc(%al) + putstr(%si)
pascal@14201 249 +# it will print out all of the registers.
pascal@14201 250 + popw %bp # load word into %si
pascal@14201 251 + jmp print_all # print %bp (status)
pascal@14201 252 +#endif
pascal@14201 253 +check_limits:
pascal@14201 254 +#ifndef SHOW_REGS
pascal@14201 255 + popw %dx
pascal@14201 256 +#endif
pascal@14201 257 + cmpb $FLOPPY_SECTORS+1, %cl # 18 sectors minimum
pascal@14201 258 + jb check_head
pascal@14201 259 + cmpb %al, %cl # max sector known ?
pascal@14201 260 + ja next_head # no -> store it
pascal@14201 261 +check_head:
pascal@14201 262 + cmpb $FLOPPY_HEADS, %dh # 2 heads minimum
pascal@14201 263 + jb check_cylinder
pascal@14201 264 + cmpb %ah, %dh # max head known ?
pascal@14201 265 + ja next_cylinder # no -> store it
pascal@14201 266 +check_cylinder:
pascal@14201 267 + pushaw
pascal@14201 268 +#ifdef SHOW_REGS
pascal@14201 269 + cmpw $0x600,%bp # disk changed ?
pascal@14201 270 + je reset_floppy
pascal@14201 271 + pushw %es # print %es (named EX)
pascal@14201 272 + pushw %dx # print %dx
pascal@14201 273 + pushw %cx # print %cx
pascal@14201 274 + pushw %bx # print %bx
pascal@14201 275 + xchgw %ax, %si
pascal@14201 276 + movb $2,%ah
pascal@14201 277 + pushw %ax # print %ax
pascal@14201 278 + movb $6,%cl
pascal@14201 279 +print_all:
pascal@14201 280 + movb $4, %ch # 4 hex digits
pascal@14201 281 +print_digit:
pascal@14201 282 + rolw $4, %bp # rotate to use low 4 bits
pascal@14201 283 + movb $0x0f, %al
pascal@14201 284 + andw %bp, %ax # %al = mask for nybble
pascal@14201 285 + addb $0x90, %al # convert %al to ascii hex
pascal@14201 286 + daa # in only four instructions!
pascal@14201 287 + adcb $0x40, %al
pascal@14201 288 + daa
pascal@14201 289 + call putc # set %ah and %bx
pascal@14201 290 + decb %ch
pascal@14201 291 + jnz print_digit
pascal@14201 292 + movb $0x20, %al # SPACE
pascal@14201 293 int $0x10
pascal@14201 294 - jmp msg_loop
pascal@14201 295 -
pascal@14201 296 -bs_die:
pascal@14201 297 - # Allow the user to press a key, then reboot
pascal@14201 298 - xorw %ax, %ax
pascal@14201 299 + loop print_loop
pascal@14201 300 + call wait
pascal@14201 301 + cbw # %ah = 0
pascal@14201 302 +reset_floppy:
pascal@14201 303 +#else
pascal@14201 304 + cbw # %ah = 0
pascal@14201 305 +#endif
pascal@14201 306 + int $0x13 # reset controler
pascal@14201 307 + popaw
pascal@14201 308 +read_sectorslp:
pascal@14201 309 + pushw %dx # some bios break dx...
pascal@14201 310 + pushw %ax # limits
pascal@14201 311 + subb %cl, %al # sectors remaining in track
pascal@14201 312 + ja tolastsect
pascal@14201 313 + movb $1, %al # 1 sector mini
pascal@14201 314 +tolastsect:
pascal@14201 315 + cbw
pascal@14201 316 + cmpw %di, %ax
pascal@14201 317 + jb more1trk
pascal@14201 318 + movw %di, %ax # sectors to read
pascal@14201 319 +more1trk:
pascal@14201 320 + pushw %ax # save context
pascal@14201 321 + movb $2, %ah # cmd: read chs
pascal@14201 322 + int $0x13
pascal@14201 323 +#ifdef SHOW_REGS
pascal@14201 324 + xchgw %ax, %bp # status
pascal@14201 325 +#endif
pascal@14201 326 +# ifdef SHOW_REGS
pascal@14201 327 + popw %si # save %ax
pascal@14201 328 + popw %ax # limits
pascal@14201 329 + popw %dx
pascal@14201 330 +# else
pascal@14201 331 + popw %dx # save %ax
pascal@14201 332 + popw %ax # limits
pascal@14201 333 +# endif
pascal@14201 334 + jc check_limits
pascal@14201 335 + xchgw %ax, %bp
pascal@14201 336 +# ifdef SHOW_REGS
pascal@14201 337 +update_regs:
pascal@14201 338 + incw %cx # next sector
pascal@14201 339 + movw %cx, %fs
pascal@14201 340 + addb $2,%bh # next location
pascal@14201 341 + decw %di # update sector counter
pascal@14201 342 + jz putcdot
pascal@14201 343 + decw %si
pascal@14201 344 + jnz update_regs
pascal@14201 345 +# else
pascal@14201 346 + addw %dx,%cx # next sector
pascal@14201 347 + addb %dl,%bh
pascal@14201 348 + addb %dl,%bh # next location
pascal@14201 349 + subw %dx,%di # update sector counter
pascal@14201 350 + popw %dx
pascal@14201 351 + jz putcdot
pascal@14201 352 +# endif
pascal@14201 353 +read_sectors:
pascal@14201 354 + movw %fs, %cx
pascal@14201 355 + xchgw %ax, %bp
pascal@14201 356 + cmpb %al,%cl # reach sector limit ?
pascal@14201 357 + jne bdendlp
pascal@14201 358 +next_head:
pascal@14201 359 + movb %cl,%al
pascal@14201 360 + incb %dh # next head
pascal@14201 361 + movb $1,%cl # first sector
pascal@14201 362 + cmpb %ah, %dh # reach head limit ?
pascal@14201 363 + jne bdendlp
pascal@14201 364 +next_cylinder:
pascal@14201 365 + movb %dh,%ah
pascal@14201 366 +# NOTE : support 256 cylinders max
pascal@14201 367 + incb %ch # next cylinder
pascal@14201 368 +read_first_sectors:
pascal@14201 369 + movb $0,%dh # first head
pascal@14201 370 +cylinder_count = 496
pascal@14201 371 + cmpb $FLOPPY_CYLINDERS,%ch # reach cylinder limit ?
pascal@14201 372 + jb bdendlp
pascal@14201 373 + cmpb cylinder_count, %ch
pascal@14201 374 + jb bdendlp
pascal@14201 375 +next_floppy:
pascal@14201 376 + movb $0,%ch # first cylinder
pascal@14201 377 + pushaw
pascal@14201 378 + movw $swap_floppy,%si
pascal@14201 379 + incb 12(%si)
pascal@14201 380 + pushw %bx
pascal@14201 381 + call putstr
pascal@14201 382 + popw %bx
pascal@14201 383 +waitfloppy:
pascal@14201 384 + call wait
pascal@14201 385 + jne waitfloppydone
pascal@14201 386 + pushw %dx # some bios break dx...
pascal@14201 387 + cbw
pascal@14201 388 + int $0x13 # reset FDC
pascal@14201 389 + movw $0x201,%ax
pascal@14201 390 +# cwd
pascal@14201 391 +# movw $1,%cx
pascal@14201 392 + int $0x13 # read first sector
pascal@14201 393 + popw %dx
pascal@14201 394 + rclb $1,%ah # floppy changed 06=>0D no error 00
pascal@14201 395 + cmpb -2(%si), %ah # 0D then 00
pascal@14201 396 + jne waitfloppy # no => try again
pascal@14201 397 + incw %si
pascal@14201 398 + orb %ah,%ah # was 00 ?
pascal@14201 399 + jne waitfloppy
pascal@14201 400 +waitfloppydone:
pascal@14201 401 + popaw
pascal@14201 402 +bdendlp:
pascal@14201 403 + jmp read_sectorslp
pascal@14201 404 +
pascal@14201 405 +putcdot:
pascal@14201 406 + pushw %ss
pascal@14201 407 + popw %es # restore es
pascal@14201 408 + movb $0x2e+3, %al # loading... message 2e = .
pascal@14201 409 +putclf:
pascal@14201 410 + subb $3, %al
pascal@14201 411 +putc:
pascal@14201 412 + movb $0xe, %ah
pascal@14201 413 + movw $7, %bx # one dot each 64k
pascal@14201 414 + int $0x10
pascal@14201 415 + cmp $0xd, %al # CR ?
pascal@14201 416 + je putclf
pascal@14201 417 + ret
pascal@14201 418 +
pascal@14201 419 +putstr:
pascal@14201 420 + movb $0xd, %al # CR
pascal@14201 421 +putcs:
pascal@14201 422 + call putc
pascal@14201 423 + lodsb
pascal@14201 424 + orb %al,%al # end of string is \0
pascal@14201 425 + jnz putcs
pascal@14201 426 + ret
pascal@14201 427 +
pascal@14201 428 +clock = 0x46C
pascal@14201 429 +wait:
pascal@14201 430 +wait4key:
pascal@14201 431 + movw $clock, %di
pascal@14201 432 +#define DELAY 5
pascal@14201 433 + movb $(DELAY*182)/10,%cl
pascal@14201 434 + addb %gs:(%di),%cl
pascal@14201 435 +waitkbd:
pascal@14201 436 + movw $0x10D, %ax # test keyboard, timeout => CR
pascal@14201 437 + cmpb %gs:(%di),%cl
pascal@14201 438 + je waitdone
pascal@14201 439 int $0x16
pascal@14201 440 - int $0x19
pascal@14201 441 + jz waitkbd
pascal@14201 442 + cbw
pascal@14201 443 + int $0x16 # eat char
pascal@14201 444 + movw %di, %gs # disable timeout
pascal@14201 445 + incw %di # clear Z
pascal@14201 446 +waitdone:
pascal@14201 447 + ret
pascal@14201 448
pascal@14201 449 - # int 0x19 should never return. In case it does anyway,
pascal@14201 450 - # invoke the BIOS reset code...
pascal@14201 451 - ljmp $0xf000,$0xfff0
pascal@14201 452 -
pascal@14201 453 - .section ".bsdata", "a"
pascal@14201 454 -bugger_off_msg:
pascal@14201 455 - .ascii "Direct booting from floppy is no longer supported.\r\n"
pascal@14201 456 - .ascii "Please use a boot loader program instead.\r\n"
pascal@14201 457 - .ascii "\n"
pascal@14201 458 - .ascii "Remove disk and press any key to reboot . . .\r\n"
pascal@14201 459 - .byte 0
pascal@14201 460 +#ifdef SHOW_REGS
pascal@14201 461 +regs: .asciz "X:"
pascal@14201 462 +#endif
pascal@14201 463
pascal@14201 464 +swap_floppy: .ascii "Insert disk 1"
pascal@14201 465 + .ascii "."
pascal@14201 466 + .byte 7,13,0
pascal@14201 467
pascal@14201 468 # Kernel attributes; used by setup. This is part 1 of the
pascal@14201 469 # header, from the old boot sector.