arch/s390/kernel/head.S

   1 /*
   2  *  arch/s390/kernel/head.S
   3  *
   4  * Copyright (C) IBM Corp. 1999,2006
   5  *
   6  *    Author(s): Hartmut Penner <hp@de.ibm.com>
   7  *               Martin Schwidefsky <schwidefsky@de.ibm.com>
   8  *               Rob van der Heij <rvdhei@iae.nl>
   9  *               Heiko Carstens <heiko.carstens@de.ibm.com>
  10  *
  11  * There are 5 different IPL methods
  12  *  1) load the image directly into ram at address 0 and do an PSW restart
  13  *  2) linload will load the image from address 0x10000 to memory 0x10000
  14  *     and start the code thru LPSW 0x0008000080010000 (VM only, deprecated)
  15  *  3) generate the tape ipl header, store the generated image on a tape
  16  *     and ipl from it
  17  *     In case of SL tape you need to IPL 5 times to get past VOL1 etc
  18  *  4) generate the vm reader ipl header, move the generated image to the
  19  *     VM reader (use option NOH!) and do a ipl from reader (VM only)
  20  *  5) direct call of start by the SALIPL loader
  21  *  We use the cpuid to distinguish between VM and native ipl
  22  *  params for kernel are pushed to 0x10400 (see setup.h)
  23  *
  24  */
  25
  26 #include <asm/setup.h>
  27 #include <asm/lowcore.h>
  28 #include <asm/asm-offsets.h>
  29 #include <asm/thread_info.h>
  30 #include <asm/page.h>
  31
  32 #ifdef CONFIG_64BIT
  33 #define ARCH_OFFSET     4
  34 #else
  35 #define ARCH_OFFSET     0
  36 #endif
  37
  38 .section ".text.head","ax"
  39 #ifndef CONFIG_IPL
  40         .org   0
  41         .long  0x00080000,0x80000000+startup    # Just a restart PSW
  42 #else
  43 #ifdef CONFIG_IPL_TAPE
  44 #define IPL_BS 1024
  45         .org   0
  46         .long  0x00080000,0x80000000+iplstart   # The first 24 bytes are loaded
  47         .long  0x27000000,0x60000001            # by ipl to addresses 0-23.
  48         .long  0x02000000,0x20000000+IPL_BS     # (a PSW and two CCWs).
  49         .long  0x00000000,0x00000000            # external old psw
  50         .long  0x00000000,0x00000000            # svc old psw
  51         .long  0x00000000,0x00000000            # program check old psw
  52         .long  0x00000000,0x00000000            # machine check old psw
  53         .long  0x00000000,0x00000000            # io old psw
  54         .long  0x00000000,0x00000000
  55         .long  0x00000000,0x00000000
  56         .long  0x00000000,0x00000000
  57         .long  0x000a0000,0x00000058            # external new psw
  58         .long  0x000a0000,0x00000060            # svc new psw
  59         .long  0x000a0000,0x00000068            # program check new psw
  60         .long  0x000a0000,0x00000070            # machine check new psw
  61         .long  0x00080000,0x80000000+.Lioint    # io new psw
  62
  63         .org   0x100
  64 #
  65 # subroutine for loading from tape
  66 # Paramters:
  67 #  R1 = device number
  68 #  R2 = load address
  69 .Lloader:
  70         st      %r14,.Lldret
  71         la      %r3,.Lorbread           # r3 = address of orb
  72         la      %r5,.Lirb               # r5 = address of irb
  73         st      %r2,.Lccwread+4         # initialize CCW data addresses
  74         lctl    %c6,%c6,.Lcr6
  75         slr     %r2,%r2
  76 .Lldlp:
  77         la      %r6,3                   # 3 retries
  78 .Lssch:
  79         ssch    0(%r3)                  # load chunk of IPL_BS bytes
  80         bnz     .Llderr
  81 .Lw4end:
  82         bas     %r14,.Lwait4io
  83         tm      8(%r5),0x82             # do we have a problem ?
  84         bnz     .Lrecov
  85         slr     %r7,%r7
  86         icm     %r7,3,10(%r5)           # get residual count
  87         lcr     %r7,%r7
  88         la      %r7,IPL_BS(%r7)         # IPL_BS-residual=#bytes read
  89         ar      %r2,%r7                 # add to total size
  90         tm      8(%r5),0x01             # found a tape mark ?
  91         bnz     .Ldone
  92         l       %r0,.Lccwread+4         # update CCW data addresses
  93         ar      %r0,%r7
  94         st      %r0,.Lccwread+4
  95         b       .Lldlp
  96 .Ldone:
  97         l       %r14,.Lldret
  98         br      %r14                    # r2 contains the total size
  99 .Lrecov:
 100         bas     %r14,.Lsense            # do the sensing
 101         bct     %r6,.Lssch              # dec. retry count & branch
 102         b       .Llderr
 103 #
 104 # Sense subroutine
 105 #
 106 .Lsense:
 107         st      %r14,.Lsnsret
 108         la      %r7,.Lorbsense
 109         ssch    0(%r7)                  # start sense command
 110         bnz     .Llderr
 111         bas     %r14,.Lwait4io
 112         l       %r14,.Lsnsret
 113         tm      8(%r5),0x82             # do we have a problem ?
 114         bnz     .Llderr
 115         br      %r14
 116 #
 117 # Wait for interrupt subroutine
 118 #
 119 .Lwait4io:
 120         lpsw    .Lwaitpsw
 121 .Lioint:
 122         c       %r1,0xb8                # compare subchannel number
 123         bne     .Lwait4io
 124         tsch    0(%r5)
 125         slr     %r0,%r0
 126         tm      8(%r5),0x82             # do we have a problem ?
 127         bnz     .Lwtexit
 128         tm      8(%r5),0x04             # got device end ?
 129         bz      .Lwait4io
 130 .Lwtexit:
 131         br      %r14
 132 .Llderr:
 133         lpsw    .Lcrash
 134
 135         .align  8
 136 .Lorbread:
 137         .long   0x00000000,0x0080ff00,.Lccwread
 138         .align  8
 139 .Lorbsense:
 140         .long   0x00000000,0x0080ff00,.Lccwsense
 141         .align  8
 142 .Lccwread:
 143         .long   0x02200000+IPL_BS,0x00000000
 144 .Lccwsense:
 145         .long   0x04200001,0x00000000
 146 .Lwaitpsw:
 147         .long   0x020a0000,0x80000000+.Lioint
 148
 149 .Lirb:  .long   0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
 150 .Lcr6:  .long   0xff000000
 151         .align  8
 152 .Lcrash:.long   0x000a0000,0x00000000
 153 .Lldret:.long   0
 154 .Lsnsret: .long 0
 155 #endif  /* CONFIG_IPL_TAPE */
 156
 157 #ifdef CONFIG_IPL_VM
 158 #define IPL_BS  0x730
 159         .org    0
 160         .long   0x00080000,0x80000000+iplstart  # The first 24 bytes are loaded
 161         .long   0x02000018,0x60000050           # by ipl to addresses 0-23.
 162         .long   0x02000068,0x60000050           # (a PSW and two CCWs).
 163         .fill   80-24,1,0x40                    # bytes 24-79 are discarded !!
 164         .long   0x020000f0,0x60000050           # The next 160 byte are loaded
 165         .long   0x02000140,0x60000050           # to addresses 0x18-0xb7
 166         .long   0x02000190,0x60000050           # They form the continuation
 167         .long   0x020001e0,0x60000050           # of the CCW program started
 168         .long   0x02000230,0x60000050           # by ipl and load the range
 169         .long   0x02000280,0x60000050           # 0x0f0-0x730 from the image
 170         .long   0x020002d0,0x60000050           # to the range 0x0f0-0x730
 171         .long   0x02000320,0x60000050           # in memory. At the end of
 172         .long   0x02000370,0x60000050           # the channel program the PSW
 173         .long   0x020003c0,0x60000050           # at location 0 is loaded.
 174         .long   0x02000410,0x60000050           # Initial processing starts
 175         .long   0x02000460,0x60000050           # at 0xf0 = iplstart.
 176         .long   0x020004b0,0x60000050
 177         .long   0x02000500,0x60000050
 178         .long   0x02000550,0x60000050
 179         .long   0x020005a0,0x60000050
 180         .long   0x020005f0,0x60000050
 181         .long   0x02000640,0x60000050
 182         .long   0x02000690,0x60000050
 183         .long   0x020006e0,0x20000050
 184
 185         .org    0xf0
 186 #
 187 # subroutine for loading cards from the reader
 188 #
 189 .Lloader:
 190         la      %r3,.Lorb               # r2 = address of orb into r2
 191         la      %r5,.Lirb               # r4 = address of irb
 192         la      %r6,.Lccws
 193         la      %r7,20
 194 .Linit:
 195         st      %r2,4(%r6)              # initialize CCW data addresses
 196         la      %r2,0x50(%r2)
 197         la      %r6,8(%r6)
 198         bct     7,.Linit
 199
 200         lctl    %c6,%c6,.Lcr6           # set IO subclass mask
 201         slr     %r2,%r2
 202 .Lldlp:
 203         ssch    0(%r3)                  # load chunk of 1600 bytes
 204         bnz     .Llderr
 205 .Lwait4irq:
 206         mvc     0x78(8),.Lnewpsw        # set up IO interrupt psw
 207         lpsw    .Lwaitpsw
 208 .Lioint:
 209         c       %r1,0xb8                # compare subchannel number
 210         bne     .Lwait4irq
 211         tsch    0(%r5)
 212
 213         slr     %r0,%r0
 214         ic      %r0,8(%r5)              # get device status
 215         chi     %r0,8                   # channel end ?
 216         be      .Lcont
 217         chi     %r0,12                  # channel end + device end ?
 218         be      .Lcont
 219
 220         l       %r0,4(%r5)
 221         s       %r0,8(%r3)              # r0/8 = number of ccws executed
 222         mhi     %r0,10                  # *10 = number of bytes in ccws
 223         lh      %r3,10(%r5)             # get residual count
 224         sr      %r0,%r3                 # #ccws*80-residual=#bytes read
 225         ar      %r2,%r0
 226
 227         br      %r14                    # r2 contains the total size
 228
 229 .Lcont:
 230         ahi     %r2,0x640               # add 0x640 to total size
 231         la      %r6,.Lccws
 232         la      %r7,20
 233 .Lincr:
 234         l       %r0,4(%r6)              # update CCW data addresses
 235         ahi     %r0,0x640
 236         st      %r0,4(%r6)
 237         ahi     %r6,8
 238         bct     7,.Lincr
 239
 240         b       .Lldlp
 241 .Llderr:
 242         lpsw    .Lcrash
 243
 244         .align  8
 245 .Lorb:  .long   0x00000000,0x0080ff00,.Lccws
 246 .Lirb:  .long   0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
 247 .Lcr6:  .long   0xff000000
 248 .Lloadp:.long   0,0
 249         .align  8
 250 .Lcrash:.long   0x000a0000,0x00000000
 251 .Lnewpsw:
 252         .long   0x00080000,0x80000000+.Lioint
 253 .Lwaitpsw:
 254         .long   0x020a0000,0x80000000+.Lioint
 255
 256         .align  8
 257 .Lccws: .rept   19
 258         .long   0x02600050,0x00000000
 259         .endr
 260         .long   0x02200050,0x00000000
 261 #endif  /* CONFIG_IPL_VM */
 262
 263 iplstart:
 264         lh      %r1,0xb8                # test if subchannel number
 265         bct     %r1,.Lnoload            #  is valid
 266         l       %r1,0xb8                # load ipl subchannel number
 267         la      %r2,IPL_BS              # load start address
 268         bas     %r14,.Lloader           # load rest of ipl image
 269         l       %r12,.Lparm             # pointer to parameter area
 270         st      %r1,IPL_DEVICE+ARCH_OFFSET-PARMAREA(%r12) # save ipl device number
 271
 272 #
 273 # load parameter file from ipl device
 274 #
 275 .Lagain1:
 276         l       %r2,.Linitrd            # ramdisk loc. is temp
 277         bas     %r14,.Lloader           # load parameter file
 278         ltr     %r2,%r2                 # got anything ?
 279         bz      .Lnopf
 280         chi     %r2,895
 281         bnh     .Lnotrunc
 282         la      %r2,895
 283 .Lnotrunc:
 284         l       %r4,.Linitrd
 285         clc     0(3,%r4),.L_hdr         # if it is HDRx
 286         bz      .Lagain1                # skip dataset header
 287         clc     0(3,%r4),.L_eof         # if it is EOFx
 288         bz      .Lagain1                # skip dateset trailer
 289         la      %r5,0(%r4,%r2)
 290         lr      %r3,%r2
 291 .Lidebc:
 292         tm      0(%r5),0x80             # high order bit set ?
 293         bo      .Ldocv                  #  yes -> convert from EBCDIC
 294         ahi     %r5,-1
 295         bct     %r3,.Lidebc
 296         b       .Lnocv
 297 .Ldocv:
 298         l       %r3,.Lcvtab
 299         tr      0(256,%r4),0(%r3)       # convert parameters to ascii
 300         tr      256(256,%r4),0(%r3)
 301         tr      512(256,%r4),0(%r3)
 302         tr      768(122,%r4),0(%r3)
 303 .Lnocv: la      %r3,COMMAND_LINE-PARMAREA(%r12) # load adr. of command line
 304         mvc     0(256,%r3),0(%r4)
 305         mvc     256(256,%r3),256(%r4)
 306         mvc     512(256,%r3),512(%r4)
 307         mvc     768(122,%r3),768(%r4)
 308         slr     %r0,%r0
 309         b       .Lcntlp
 310 .Ldelspc:
 311         ic      %r0,0(%r2,%r3)
 312         chi     %r0,0x20                # is it a space ?
 313         be      .Lcntlp
 314         ahi     %r2,1
 315         b       .Leolp
 316 .Lcntlp:
 317         brct    %r2,.Ldelspc
 318 .Leolp:
 319         slr     %r0,%r0
 320         stc     %r0,0(%r2,%r3)          # terminate buffer
 321 .Lnopf:
 322
 323 #
 324 # load ramdisk from ipl device
 325 #
 326 .Lagain2:
 327         l       %r2,.Linitrd            # addr of ramdisk
 328         st      %r2,INITRD_START+ARCH_OFFSET-PARMAREA(%r12)
 329         bas     %r14,.Lloader           # load ramdisk
 330         st      %r2,INITRD_SIZE+ARCH_OFFSET-PARMAREA(%r12) # store size of rd
 331         ltr     %r2,%r2
 332         bnz     .Lrdcont
 333         st      %r2,INITRD_START+ARCH_OFFSET-PARMAREA(%r12) # no ramdisk found
 334 .Lrdcont:
 335         l       %r2,.Linitrd
 336
 337         clc     0(3,%r2),.L_hdr         # skip HDRx and EOFx
 338         bz      .Lagain2
 339         clc     0(3,%r2),.L_eof
 340         bz      .Lagain2
 341
 342 #ifdef CONFIG_IPL_VM
 343 #
 344 # reset files in VM reader
 345 #
 346         stidp   __LC_CPUID              # store cpuid
 347         tm      __LC_CPUID,0xff         # running VM ?
 348         bno     .Lnoreset
 349         la      %r2,.Lreset
 350         lhi     %r3,26
 351         diag    %r2,%r3,8
 352         la      %r5,.Lirb
 353         stsch   0(%r5)                  # check if irq is pending
 354         tm      30(%r5),0x0f            # by verifying if any of the
 355         bnz     .Lwaitforirq            # activity or status control
 356         tm      31(%r5),0xff            # bits is set in the schib
 357         bz      .Lnoreset
 358 .Lwaitforirq:
 359         mvc     0x78(8),.Lrdrnewpsw     # set up IO interrupt psw
 360 .Lwaitrdrirq:
 361         lpsw    .Lrdrwaitpsw
 362 .Lrdrint:
 363         c       %r1,0xb8                # compare subchannel number
 364         bne     .Lwaitrdrirq
 365         la      %r5,.Lirb
 366         tsch    0(%r5)
 367 .Lnoreset:
 368         b       .Lnoload
 369
 370         .align  8
 371 .Lrdrnewpsw:
 372         .long   0x00080000,0x80000000+.Lrdrint
 373 .Lrdrwaitpsw:
 374         .long   0x020a0000,0x80000000+.Lrdrint
 375 #endif
 376
 377 #
 378 # everything loaded, go for it
 379 #
 380 .Lnoload:
 381         l       %r1,.Lstartup
 382         br      %r1
 383
 384 .Linitrd:.long _end + 0x400000          # default address of initrd
 385 .Lparm: .long  PARMAREA
 386 .Lstartup: .long startup
 387 .Lcvtab:.long   _ebcasc                 # ebcdic to ascii table
 388 .Lreset:.byte   0xc3,0xc8,0xc1,0xd5,0xc7,0xc5,0x40,0xd9,0xc4,0xd9,0x40
 389         .byte   0xc1,0xd3,0xd3,0x40,0xd2,0xc5,0xc5,0xd7,0x40,0xd5,0xd6
 390         .byte   0xc8,0xd6,0xd3,0xc4     # "change rdr all keep nohold"
 391 .L_eof: .long   0xc5d6c600       /* C'EOF' */
 392 .L_hdr: .long   0xc8c4d900       /* C'HDR' */
 393
 394 #endif  /* CONFIG_IPL */
 395
 396 #
 397 # SALIPL loader support. Based on a patch by Rob van der Heij.
 398 # This entry point is called directly from the SALIPL loader and
 399 # doesn't need a builtin ipl record.
 400 #
 401         .org    0x800
 402         .globl  start
 403 start:
 404         stm     %r0,%r15,0x07b0         # store registers
 405         basr    %r12,%r0
 406 .base:
 407         l       %r11,.parm
 408         l       %r8,.cmd                # pointer to command buffer
 409
 410         ltr     %r9,%r9                 # do we have SALIPL parameters?
 411         bp      .sk8x8
 412
 413         mvc     0(64,%r8),0x00b0        # copy saved registers
 414         xc      64(240-64,%r8),0(%r8)   # remainder of buffer
 415         tr      0(64,%r8),.lowcase
 416         b       .gotr
 417 .sk8x8:
 418         mvc     0(240,%r8),0(%r9)       # copy iplparms into buffer
 419 .gotr:
 420         l       %r10,.tbl               # EBCDIC to ASCII table
 421         tr      0(240,%r8),0(%r10)
 422         slr     %r0,%r0
 423         st      %r0,INITRD_SIZE+ARCH_OFFSET-PARMAREA(%r11)
 424         st      %r0,INITRD_START+ARCH_OFFSET-PARMAREA(%r11)
 425         j       startup                 # continue with startup
 426 .tbl:   .long   _ebcasc                 # translate table
 427 .cmd:   .long   COMMAND_LINE            # address of command line buffer
 428 .parm:  .long   PARMAREA
 429 .lowcase:
 430         .byte 0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07
 431         .byte 0x08,0x09,0x0a,0x0b,0x0c,0x0d,0x0e,0x0f
 432         .byte 0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17
 433         .byte 0x18,0x19,0x1a,0x1b,0x1c,0x1d,0x1e,0x1f
 434         .byte 0x20,0x21,0x22,0x23,0x24,0x25,0x26,0x27
 435         .byte 0x28,0x29,0x2a,0x2b,0x2c,0x2d,0x2e,0x2f
 436         .byte 0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37
 437         .byte 0x38,0x39,0x3a,0x3b,0x3c,0x3d,0x3e,0x3f
 438         .byte 0x40,0x41,0x42,0x43,0x44,0x45,0x46,0x47
 439         .byte 0x48,0x49,0x4a,0x4b,0x4c,0x4d,0x4e,0x4f
 440         .byte 0x50,0x51,0x52,0x53,0x54,0x55,0x56,0x57
 441         .byte 0x58,0x59,0x5a,0x5b,0x5c,0x5d,0x5e,0x5f
 442         .byte 0x60,0x61,0x62,0x63,0x64,0x65,0x66,0x67
 443         .byte 0x68,0x69,0x6a,0x6b,0x6c,0x6d,0x6e,0x6f
 444         .byte 0x70,0x71,0x72,0x73,0x74,0x75,0x76,0x77
 445         .byte 0x78,0x79,0x7a,0x7b,0x7c,0x7d,0x7e,0x7f
 446
 447         .byte 0x80,0x81,0x82,0x83,0x84,0x85,0x86,0x87
 448         .byte 0x88,0x89,0x8a,0x8b,0x8c,0x8d,0x8e,0x8f
 449         .byte 0x90,0x91,0x92,0x93,0x94,0x95,0x96,0x97
 450         .byte 0x98,0x99,0x9a,0x9b,0x9c,0x9d,0x9e,0x9f
 451         .byte 0xa0,0xa1,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7
 452         .byte 0xa8,0xa9,0xaa,0xab,0xac,0xad,0xae,0xaf
 453         .byte 0xb0,0xb1,0xb2,0xb3,0xb4,0xb5,0xb6,0xb7
 454         .byte 0xb8,0xb9,0xba,0xbb,0xbc,0xbd,0xbe,0xbf
 455         .byte 0xc0,0x81,0x82,0x83,0x84,0x85,0x86,0x87   # .abcdefg
 456         .byte 0x88,0x89,0xca,0xcb,0xcc,0xcd,0xce,0xcf   # hi
 457         .byte 0xd0,0x91,0x92,0x93,0x94,0x95,0x96,0x97   # .jklmnop
 458         .byte 0x98,0x99,0xda,0xdb,0xdc,0xdd,0xde,0xdf   # qr
 459         .byte 0xe0,0xe1,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7   # ..stuvwx
 460         .byte 0xa8,0xa9,0xea,0xeb,0xec,0xed,0xee,0xef   # yz
 461         .byte 0xf0,0xf1,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7
 462         .byte 0xf8,0xf9,0xfa,0xfb,0xfc,0xfd,0xfe,0xff
 463
 464 #
 465 # startup-code at 0x10000, running in absolute addressing mode
 466 # this is called either by the ipl loader or directly by PSW restart
 467 # or linload or SALIPL
 468 #
 469         .org    0x10000
 470 startup:basr    %r13,0                  # get base
 471 .LPG0:
 472         xc      0x200(256),0x200        # partially clear lowcore
 473         xc      0x300(256),0x300
 474         l       %r1,5f-.LPG0(%r13)
 475         stck    0(%r1)
 476         spt     6f-.LPG0(%r13)
 477         mvc     __LC_LAST_UPDATE_CLOCK(8),0(%r1)
 478         mvc     __LC_LAST_UPDATE_TIMER(8),6f-.LPG0(%r13)
 479         mvc     __LC_EXIT_TIMER(8),5f-.LPG0(%r13)
 480 #ifndef CONFIG_MARCH_G5
 481         # check processor version against MARCH_{G5,Z900,Z990,Z9_109,Z10}
 482         stidp   __LC_CPUID              # store cpuid
 483         lhi     %r0,(3f-2f) / 2
 484         la      %r1,2f-.LPG0(%r13)
 485 0:      clc     __LC_CPUID+4(2),0(%r1)
 486         jne     3f
 487         lpsw    1f-.LPG0(13)            # machine type not good enough, crash
 488         .align 16
 489 1:      .long   0x000a0000,0x00000000
 490 2:
 491 #if defined(CONFIG_MARCH_Z10)
 492         .short 0x9672, 0x2064, 0x2066, 0x2084, 0x2086, 0x2094, 0x2096
 493 #elif defined(CONFIG_MARCH_Z9_109)
 494         .short 0x9672, 0x2064, 0x2066, 0x2084, 0x2086
 495 #elif defined(CONFIG_MARCH_Z990)
 496         .short 0x9672, 0x2064, 0x2066
 497 #elif defined(CONFIG_MARCH_Z900)
 498         .short 0x9672
 499 #endif
 500 3:      la      %r1,2(%r1)
 501         brct    %r0,0b
 502 #endif
 503
 504         l       %r13,4f-.LPG0(%r13)
 505         b       0(%r13)
 506         .align  4
 507 4:      .long   startup_continue
 508 5:      .long   sched_clock_base_cc
 509         .align  8
 510 6:      .long   0x7fffffff,0xffffffff
 511
 512 #
 513 # params at 10400 (setup.h)
 514 #
 515         .org    PARMAREA
 516         .long   0,0                     # IPL_DEVICE
 517         .long   0,0                     # INITRD_START
 518         .long   0,0                     # INITRD_SIZE
 519
 520         .org    COMMAND_LINE
 521         .byte   "root=/dev/ram0 ro"
 522         .byte   0
 523
 524 #ifdef CONFIG_64BIT
 525 #include "head64.S"
 526 #else
 527 #include "head31.S"
 528 #endif