arch/s390/kernel/head.S

   1 /*
   2  *  arch/s390/kernel/head.S
   3  *
   4  *  S390 version
   5  *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
   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  *
  10  * There are 5 different IPL methods
  11  *  1) load the image directly into ram at address 0 and do an PSW restart
  12  *  2) linload will load the image from address 0x10000 to memory 0x10000
  13  *     and start the code thru LPSW 0x0008000080010000 (VM only, deprecated)
  14  *  3) generate the tape ipl header, store the generated image on a tape
  15  *     and ipl from it
  16  *     In case of SL tape you need to IPL 5 times to get past VOL1 etc
  17  *  4) generate the vm reader ipl header, move the generated image to the
  18  *     VM reader (use option NOH!) and do a ipl from reader (VM only)
  19  *  5) direct call of start by the SALIPL loader
  20  *  We use the cpuid to distinguish between VM and native ipl
  21  *  params for kernel are pushed to 0x10400 (see setup.h)
  22
  23     Changes:
  24     Okt 25 2000 <rvdheij@iae.nl>
  25         added code to skip HDR and EOF to allow SL tape IPL (5 retries)
  26         changed first CCW from rewind to backspace block
  27
  28  */
  29
  30 #include <linux/config.h>
  31 #include <asm/setup.h>
  32 #include <asm/lowcore.h>
  33 #include <asm/offsets.h>
  34 #include <asm/thread_info.h>
  35 #include <asm/page.h>
  36
  37 #ifndef CONFIG_IPL
  38         .org   0
  39         .long  0x00080000,0x80000000+startup   # Just a restart PSW
  40 #else
  41 #ifdef CONFIG_IPL_TAPE
  42 #define IPL_BS 1024
  43         .org   0
  44         .long  0x00080000,0x80000000+iplstart  # The first 24 bytes are loaded
  45         .long  0x27000000,0x60000001           # by ipl to addresses 0-23.
  46         .long  0x02000000,0x20000000+IPL_BS    # (a PSW and two CCWs).
  47         .long  0x00000000,0x00000000           # external old psw
  48         .long  0x00000000,0x00000000           # svc old psw
  49         .long  0x00000000,0x00000000           # program check old psw
  50         .long  0x00000000,0x00000000           # machine check old psw
  51         .long  0x00000000,0x00000000           # io old psw
  52         .long  0x00000000,0x00000000
  53         .long  0x00000000,0x00000000
  54         .long  0x00000000,0x00000000
  55         .long  0x000a0000,0x00000058           # external new psw
  56         .long  0x000a0000,0x00000060           # svc new psw
  57         .long  0x000a0000,0x00000068           # program check new psw
  58         .long  0x000a0000,0x00000070           # machine check new psw
  59         .long  0x00080000,0x80000000+.Lioint   # io new psw
  60
  61         .org   0x100
  62 #
  63 # subroutine for loading from tape
  64 # Paramters:
  65 #  R1 = device number
  66 #  R2 = load address
  67 .Lloader:
  68         st    %r14,.Lldret
  69         la    %r3,.Lorbread                    # r3 = address of orb
  70         la    %r5,.Lirb                        # r5 = address of irb
  71         st    %r2,.Lccwread+4                  # initialize CCW data addresses
  72         lctl  %c6,%c6,.Lcr6
  73         slr   %r2,%r2
  74 .Lldlp:
  75         la    %r6,3                            # 3 retries
  76 .Lssch:
  77         ssch  0(%r3)                           # load chunk of IPL_BS bytes
  78         bnz   .Llderr
  79 .Lw4end:
  80         bas   %r14,.Lwait4io
  81         tm    8(%r5),0x82                      # do we have a problem ?
  82         bnz   .Lrecov
  83         slr   %r7,%r7
  84         icm   %r7,3,10(%r5)                    # get residual count
  85         lcr   %r7,%r7
  86         la    %r7,IPL_BS(%r7)                  # IPL_BS-residual=#bytes read
  87         ar    %r2,%r7                          # add to total size
  88         tm    8(%r5),0x01                      # found a tape mark ?
  89         bnz   .Ldone
  90         l     %r0,.Lccwread+4                  # update CCW data addresses
  91         ar    %r0,%r7
  92         st    %r0,.Lccwread+4
  93         b     .Lldlp
  94 .Ldone:
  95         l     %r14,.Lldret
  96         br    %r14                             # r2 contains the total size
  97 .Lrecov:
  98         bas   %r14,.Lsense                     # do the sensing
  99         bct   %r6,.Lssch                       # dec. retry count & branch
 100         b     .Llderr
 101 #
 102 # Sense subroutine
 103 #
 104 .Lsense:
 105         st    %r14,.Lsnsret
 106         la    %r7,.Lorbsense
 107         ssch  0(%r7)                           # start sense command
 108         bnz   .Llderr
 109         bas   %r14,.Lwait4io
 110         l     %r14,.Lsnsret
 111         tm    8(%r5),0x82                      # do we have a problem ?
 112         bnz   .Llderr
 113         br    %r14
 114 #
 115 # Wait for interrupt subroutine
 116 #
 117 .Lwait4io:
 118         lpsw  .Lwaitpsw
 119 .Lioint:
 120         c     %r1,0xb8                         # compare subchannel number
 121         bne   .Lwait4io
 122         tsch  0(%r5)
 123         slr   %r0,%r0
 124         tm    8(%r5),0x82                      # do we have a problem ?
 125         bnz   .Lwtexit
 126         tm    8(%r5),0x04                      # got device end ?
 127         bz    .Lwait4io
 128 .Lwtexit:
 129         br    %r14
 130 .Llderr:
 131         lpsw  .Lcrash
 132
 133         .align 8
 134 .Lorbread:
 135         .long  0x00000000,0x0080ff00,.Lccwread
 136         .align 8
 137 .Lorbsense:
 138         .long  0x00000000,0x0080ff00,.Lccwsense
 139         .align 8
 140 .Lccwread:
 141         .long  0x02200000+IPL_BS,0x00000000
 142 .Lccwsense:
 143         .long  0x04200001,0x00000000
 144 .Lwaitpsw:
 145         .long  0x020a0000,0x80000000+.Lioint
 146
 147 .Lirb:  .long  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
 148 .Lcr6:  .long  0xff000000
 149         .align 8
 150 .Lcrash:.long  0x000a0000,0x00000000
 151 .Lldret:.long  0
 152 .Lsnsret: .long 0
 153 #endif  /* CONFIG_IPL_TAPE */
 154
 155 #ifdef CONFIG_IPL_VM
 156 #define IPL_BS 0x730
 157         .org   0
 158         .long  0x00080000,0x80000000+iplstart  # The first 24 bytes are loaded
 159         .long  0x02000018,0x60000050           # by ipl to addresses 0-23.
 160         .long  0x02000068,0x60000050           # (a PSW and two CCWs).
 161         .fill  80-24,1,0x40                    # bytes 24-79 are discarded !!
 162         .long  0x020000f0,0x60000050           # The next 160 byte are loaded
 163         .long  0x02000140,0x60000050           # to addresses 0x18-0xb7
 164         .long  0x02000190,0x60000050           # They form the continuation
 165         .long  0x020001e0,0x60000050           # of the CCW program started
 166         .long  0x02000230,0x60000050           # by ipl and load the range
 167         .long  0x02000280,0x60000050           # 0x0f0-0x730 from the image
 168         .long  0x020002d0,0x60000050           # to the range 0x0f0-0x730
 169         .long  0x02000320,0x60000050           # in memory. At the end of
 170         .long  0x02000370,0x60000050           # the channel program the PSW
 171         .long  0x020003c0,0x60000050           # at location 0 is loaded.
 172         .long  0x02000410,0x60000050           # Initial processing starts
 173         .long  0x02000460,0x60000050           # at 0xf0 = iplstart.
 174         .long  0x020004b0,0x60000050
 175         .long  0x02000500,0x60000050
 176         .long  0x02000550,0x60000050
 177         .long  0x020005a0,0x60000050
 178         .long  0x020005f0,0x60000050
 179         .long  0x02000640,0x60000050
 180         .long  0x02000690,0x60000050
 181         .long  0x020006e0,0x20000050
 182
 183         .org   0xf0
 184 #
 185 # subroutine for loading cards from the reader
 186 #
 187 .Lloader:
 188         la    %r3,.Lorb                        # r2 = address of orb into r2
 189         la    %r5,.Lirb                        # r4 = address of irb
 190         la    %r6,.Lccws
 191         la    %r7,20
 192 .Linit:
 193         st    %r2,4(%r6)                       # initialize CCW data addresses
 194         la    %r2,0x50(%r2)
 195         la    %r6,8(%r6)
 196         bct   7,.Linit
 197
 198         lctl  %c6,%c6,.Lcr6                    # set IO subclass mask
 199         slr   %r2,%r2
 200 .Lldlp:
 201         ssch  0(%r3)                           # load chunk of 1600 bytes
 202         bnz   .Llderr
 203 .Lwait4irq:
 204         mvc   __LC_IO_NEW_PSW(8),.Lnewpsw      # set up IO interrupt psw
 205         lpsw  .Lwaitpsw
 206 .Lioint:
 207         c     %r1,0xb8                         # compare subchannel number
 208         bne   .Lwait4irq
 209         tsch  0(%r5)
 210
 211         slr   %r0,%r0
 212         ic    %r0,8(%r5)                       # get device status
 213         chi   %r0,8                            # channel end ?
 214         be    .Lcont
 215         chi   %r0,12                           # channel end + device end ?
 216         be    .Lcont
 217
 218         l     %r0,4(%r5)
 219         s     %r0,8(%r3)                       # r0/8 = number of ccws executed
 220         mhi   %r0,10                           # *10 = number of bytes in ccws
 221         lh    %r3,10(%r5)                      # get residual count
 222         sr    %r0,%r3                          # #ccws*80-residual=#bytes read
 223         ar    %r2,%r0
 224
 225         br    %r14                             # r2 contains the total size
 226
 227 .Lcont:
 228         ahi   %r2,0x640                        # add 0x640 to total size
 229         la    %r6,.Lccws
 230         la    %r7,20
 231 .Lincr:
 232         l     %r0,4(%r6)                       # update CCW data addresses
 233         ahi   %r0,0x640
 234         st    %r0,4(%r6)
 235         ahi   %r6,8
 236         bct   7,.Lincr
 237
 238         b     .Lldlp
 239 .Llderr:
 240         lpsw  .Lcrash
 241
 242         .align 8
 243 .Lorb:  .long  0x00000000,0x0080ff00,.Lccws
 244 .Lirb:  .long  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
 245 .Lcr6:  .long  0xff000000
 246 .Lloadp:.long  0,0
 247         .align 8
 248 .Lcrash:.long  0x000a0000,0x00000000
 249 .Lnewpsw:
 250         .long  0x00080000,0x80000000+.Lioint
 251 .Lwaitpsw:
 252         .long  0x020a0000,0x80000000+.Lioint
 253
 254         .align 8
 255 .Lccws: .rept  19
 256         .long  0x02600050,0x00000000
 257         .endr
 258         .long  0x02200050,0x00000000
 259 #endif  /* CONFIG_IPL_VM */
 260
 261 iplstart:
 262         lh    %r1,0xb8                         # test if subchannel number
 263         bct   %r1,.Lnoload                     #  is valid
 264         l     %r1,0xb8                         # load ipl subchannel number
 265         la    %r2,IPL_BS                       # load start address
 266         bas   %r14,.Lloader                    # load rest of ipl image
 267         l     %r12,.Lparm                      # pointer to parameter area
 268         st    %r1,IPL_DEVICE-PARMAREA(%r12)    # store ipl device number
 269
 270 #
 271 # load parameter file from ipl device
 272 #
 273 .Lagain1:
 274         l     %r2,INITRD_START-PARMAREA(%r12)  # use ramdisk location as temp
 275         bas   %r14,.Lloader                    # load parameter file
 276         ltr   %r2,%r2                          # got anything ?
 277         bz    .Lnopf
 278         chi   %r2,895
 279         bnh   .Lnotrunc
 280         la    %r2,895
 281 .Lnotrunc:
 282         l     %r4,INITRD_START-PARMAREA(%r12)
 283         clc   0(3,%r4),.L_hdr                  # if it is HDRx
 284         bz    .Lagain1                         # skip dataset header
 285         clc   0(3,%r4),.L_eof                  # if it is EOFx
 286         bz    .Lagain1                         # skip dateset trailer
 287         la    %r5,0(%r4,%r2)
 288         lr    %r3,%r2
 289 .Lidebc:
 290         tm    0(%r5),0x80                      # high order bit set ?
 291         bo    .Ldocv                           #  yes -> convert from EBCDIC
 292         ahi   %r5,-1
 293         bct   %r3,.Lidebc
 294         b     .Lnocv
 295 .Ldocv:
 296         l     %r3,.Lcvtab
 297         tr    0(256,%r4),0(%r3)                # convert parameters to ascii
 298         tr    256(256,%r4),0(%r3)
 299         tr    512(256,%r4),0(%r3)
 300         tr    768(122,%r4),0(%r3)
 301 .Lnocv: la    %r3,COMMAND_LINE-PARMAREA(%r12)  # load adr. of command line
 302         mvc   0(256,%r3),0(%r4)
 303         mvc   256(256,%r3),256(%r4)
 304         mvc   512(256,%r3),512(%r4)
 305         mvc   768(122,%r3),768(%r4)
 306         slr   %r0,%r0
 307         b     .Lcntlp
 308 .Ldelspc:
 309         ic    %r0,0(%r2,%r3)
 310         chi   %r0,0x20                         # is it a space ?
 311         be    .Lcntlp
 312         ahi   %r2,1
 313         b     .Leolp
 314 .Lcntlp:
 315         brct  %r2,.Ldelspc
 316 .Leolp:
 317         slr   %r0,%r0
 318         stc   %r0,0(%r2,%r3)                   # terminate buffer
 319 .Lnopf:
 320
 321 #
 322 # load ramdisk from ipl device
 323 #
 324 .Lagain2:
 325         l     %r2,INITRD_START-PARMAREA(%r12)  # load adr. of ramdisk
 326         bas   %r14,.Lloader                    # load ramdisk
 327         st    %r2,INITRD_SIZE-PARMAREA(%r12)   # store size of ramdisk
 328         ltr   %r2,%r2
 329         bnz   .Lrdcont
 330         st    %r2,INITRD_START-PARMAREA(%r12)  # no ramdisk found, null it
 331 .Lrdcont:
 332         l     %r2,INITRD_START-PARMAREA(%r12)
 333
 334         clc   0(3,%r2),.L_hdr                  # skip HDRx and EOFx
 335         bz    .Lagain2
 336         clc   0(3,%r2),.L_eof
 337         bz    .Lagain2
 338
 339 #ifdef CONFIG_IPL_VM
 340 #
 341 # reset files in VM reader
 342 #
 343         stidp __LC_CPUID                       # store cpuid
 344         tm    __LC_CPUID,0xff                  # running VM ?
 345         bno   .Lnoreset
 346         la    %r2,.Lreset
 347         lhi   %r3,26
 348         diag  %r2,%r3,8
 349         mvc   0x78(8),.Lrdrnewpsw              # set up IO interrupt psw
 350 .Lwaitrdrirq:
 351         lpsw  .Lrdrwaitpsw
 352 .Lrdrint:
 353         c     %r1,0xb8                         # compare subchannel number
 354         bne   .Lwaitrdrirq
 355         la    %r5,.Lirb
 356         tsch  0(%r5)
 357 .Lnoreset:
 358         b     .Lnoload
 359
 360         .align 8
 361 .Lrdrnewpsw:
 362         .long  0x00080000,0x80000000+.Lrdrint
 363 .Lrdrwaitpsw:
 364         .long  0x020a0000,0x80000000+.Lrdrint
 365 #endif
 366
 367 #
 368 # everything loaded, go for it
 369 #
 370 .Lnoload:
 371         l     %r1,.Lstartup
 372         br    %r1
 373
 374 .Lparm: .long  PARMAREA
 375 .Lstartup: .long startup
 376 .Lcvtab:.long  _ebcasc                         # ebcdic to ascii table
 377 .Lreset:.byte  0xc3,0xc8,0xc1,0xd5,0xc7,0xc5,0x40,0xd9,0xc4,0xd9,0x40
 378         .byte  0xc1,0xd3,0xd3,0x40,0xd2,0xc5,0xc5,0xd7,0x40,0xd5,0xd6
 379         .byte  0xc8,0xd6,0xd3,0xc4             # "change rdr all keep nohold"
 380 .L_eof: .long  0xc5d6c600       /* C'EOF' */
 381 .L_hdr: .long  0xc8c4d900       /* C'HDR' */
 382
 383 #endif  /* CONFIG_IPL */
 384
 385 #
 386 # SALIPL loader support. Based on a patch by Rob van der Heij.
 387 # This entry point is called directly from the SALIPL loader and
 388 # doesn't need a builtin ipl record.
 389 #
 390         .org  0x800
 391         .globl start
 392 start:
 393         stm   %r0,%r15,0x07b0           # store registers
 394         basr  %r12,%r0
 395 .base:
 396         l     %r11,.parm
 397         l     %r8,.cmd                  # pointer to command buffer
 398
 399         ltr   %r9,%r9                   # do we have SALIPL parameters?
 400         bp    .sk8x8
 401
 402         mvc   0(64,%r8),0x00b0          # copy saved registers
 403         xc    64(240-64,%r8),0(%r8)     # remainder of buffer
 404         tr    0(64,%r8),.lowcase
 405         b     .gotr
 406 .sk8x8:
 407         mvc   0(240,%r8),0(%r9)         # copy iplparms into buffer
 408 .gotr:
 409         l     %r10,.tbl                 # EBCDIC to ASCII table
 410         tr    0(240,%r8),0(%r10)
 411         stidp __LC_CPUID                # Are we running on VM maybe
 412         cli   __LC_CPUID,0xff
 413         bnz   .test
 414         .long 0x83300060                # diag 3,0,x'0060' - storage size
 415         b     .done
 416 .test:
 417         mvc   0x68(8),.pgmnw            # set up pgm check handler
 418         l     %r2,.fourmeg
 419         lr    %r3,%r2
 420         bctr  %r3,%r0                   # 4M-1
 421 .loop:  iske  %r0,%r3
 422         ar    %r3,%r2
 423 .pgmx:
 424         sr    %r3,%r2
 425         la    %r3,1(%r3)
 426 .done:
 427         l     %r1,.memsize
 428         st    %r3,0(%r1)
 429         slr   %r0,%r0
 430         st    %r0,INITRD_SIZE-PARMAREA(%r11)
 431         st    %r0,INITRD_START-PARMAREA(%r11)
 432         j     startup                   # continue with startup
 433 .tbl:   .long _ebcasc                   # translate table
 434 .cmd:   .long COMMAND_LINE              # address of command line buffer
 435 .parm:  .long PARMAREA
 436 .memsize: .long memory_size
 437 .fourmeg: .long 0x00400000              # 4M
 438 .pgmnw: .long 0x00080000,.pgmx
 439 .lowcase:
 440         .byte 0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07
 441         .byte 0x08,0x09,0x0a,0x0b,0x0c,0x0d,0x0e,0x0f
 442         .byte 0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17
 443         .byte 0x18,0x19,0x1a,0x1b,0x1c,0x1d,0x1e,0x1f
 444         .byte 0x20,0x21,0x22,0x23,0x24,0x25,0x26,0x27
 445         .byte 0x28,0x29,0x2a,0x2b,0x2c,0x2d,0x2e,0x2f
 446         .byte 0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37
 447         .byte 0x38,0x39,0x3a,0x3b,0x3c,0x3d,0x3e,0x3f
 448         .byte 0x40,0x41,0x42,0x43,0x44,0x45,0x46,0x47
 449         .byte 0x48,0x49,0x4a,0x4b,0x4c,0x4d,0x4e,0x4f
 450         .byte 0x50,0x51,0x52,0x53,0x54,0x55,0x56,0x57
 451         .byte 0x58,0x59,0x5a,0x5b,0x5c,0x5d,0x5e,0x5f
 452         .byte 0x60,0x61,0x62,0x63,0x64,0x65,0x66,0x67
 453         .byte 0x68,0x69,0x6a,0x6b,0x6c,0x6d,0x6e,0x6f
 454         .byte 0x70,0x71,0x72,0x73,0x74,0x75,0x76,0x77
 455         .byte 0x78,0x79,0x7a,0x7b,0x7c,0x7d,0x7e,0x7f
 456
 457         .byte 0x80,0x81,0x82,0x83,0x84,0x85,0x86,0x87
 458         .byte 0x88,0x89,0x8a,0x8b,0x8c,0x8d,0x8e,0x8f
 459         .byte 0x90,0x91,0x92,0x93,0x94,0x95,0x96,0x97
 460         .byte 0x98,0x99,0x9a,0x9b,0x9c,0x9d,0x9e,0x9f
 461         .byte 0xa0,0xa1,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7
 462         .byte 0xa8,0xa9,0xaa,0xab,0xac,0xad,0xae,0xaf
 463         .byte 0xb0,0xb1,0xb2,0xb3,0xb4,0xb5,0xb6,0xb7
 464         .byte 0xb8,0xb9,0xba,0xbb,0xbc,0xbd,0xbe,0xbf
 465         .byte 0xc0,0x81,0x82,0x83,0x84,0x85,0x86,0x87   # .abcdefg
 466         .byte 0x88,0x89,0xca,0xcb,0xcc,0xcd,0xce,0xcf   # hi
 467         .byte 0xd0,0x91,0x92,0x93,0x94,0x95,0x96,0x97   # .jklmnop
 468         .byte 0x98,0x99,0xda,0xdb,0xdc,0xdd,0xde,0xdf   # qr
 469         .byte 0xe0,0xe1,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7   # ..stuvwx
 470         .byte 0xa8,0xa9,0xea,0xeb,0xec,0xed,0xee,0xef   # yz
 471         .byte 0xf0,0xf1,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7
 472         .byte 0xf8,0xf9,0xfa,0xfb,0xfc,0xfd,0xfe,0xff
 473
 474 #
 475 # startup-code at 0x10000, running in real mode
 476 # this is called either by the ipl loader or directly by PSW restart
 477 # or linload or SALIPL
 478 #
 479         .org  0x10000
 480 startup:basr  %r13,0                     # get base
 481 .LPG1:  lctl  %c0,%c15,.Lctl-.LPG1(%r13) # load control registers
 482         la    %r12,_pstart-.LPG1(%r13)   # pointer to parameter area
 483                                          # move IPL device to lowcore
 484         mvc   __LC_IPLDEV(4),IPL_DEVICE-PARMAREA(%r12)
 485
 486 #
 487 # clear bss memory
 488 #
 489         l     %r2,.Lbss_bgn-.LPG1(%r13) # start of bss
 490         l     %r3,.Lbss_end-.LPG1(%r13) # end of bss
 491         sr    %r3,%r2                   # length of bss
 492         sr    %r4,%r4                   #
 493         sr    %r5,%r5                   # set src,length and pad to zero
 494         sr    %r0,%r0                   #
 495         mvcle %r2,%r4,0                 # clear mem
 496         jo    .-4                       # branch back, if not finish
 497
 498         l     %r2,.Lrcp-.LPG1(%r13)     # Read SCP forced command word
 499 .Lservicecall:
 500         stosm .Lpmask-.LPG1(%r13),0x01  # authorize ext interrupts
 501
 502         stctl %r0, %r0,.Lcr-.LPG1(%r13) # get cr0
 503         la    %r1,0x200                 # set bit 22
 504         o     %r1,.Lcr-.LPG1(%r13)      # or old cr0 with r1
 505         st    %r1,.Lcr-.LPG1(%r13)
 506         lctl  %r0, %r0,.Lcr-.LPG1(%r13) # load modified cr0
 507
 508         mvc   __LC_EXT_NEW_PSW(8),.Lpcext-.LPG1(%r13) # set postcall psw
 509         la    %r1, .Lsclph-.LPG1(%r13)
 510         a     %r1,__LC_EXT_NEW_PSW+4    # set handler
 511         st    %r1,__LC_EXT_NEW_PSW+4
 512
 513         la    %r4,_pstart-.LPG1(%r13)   # %r4 is our index for sccb stuff
 514         la    %r1, .Lsccb-PARMAREA(%r4) # our sccb
 515         .insn rre,0xb2200000,%r2,%r1    # service call
 516         ipm   %r1
 517         srl   %r1,28                    # get cc code
 518         xr    %r3, %r3
 519         chi   %r1,3
 520         be    .Lfchunk-.LPG1(%r13)      # leave
 521         chi   %r1,2
 522         be    .Lservicecall-.LPG1(%r13)
 523         lpsw  .Lwaitsclp-.LPG1(%r13)
 524 .Lsclph:
 525         lh    %r1,.Lsccbr-PARMAREA(%r4)
 526         chi   %r1,0x10                  # 0x0010 is the sucess code
 527         je    .Lprocsccb                # let's process the sccb
 528         chi   %r1,0x1f0
 529         bne   .Lfchunk-.LPG1(%r13)      # unhandled error code
 530         c     %r2, .Lrcp-.LPG1(%r13)    # Did we try Read SCP forced
 531         bne   .Lfchunk-.LPG1(%r13)      # if no, give up
 532         l     %r2, .Lrcp2-.LPG1(%r13)   # try with Read SCP
 533         b     .Lservicecall-.LPG1(%r13)
 534 .Lprocsccb:
 535         lhi   %r1,0
 536         icm   %r1,3,.Lscpincr1-PARMAREA(%r4) # use this one if != 0
 537         jnz   .Lscnd
 538         lhi   %r1,0x800                 # otherwise report 2GB
 539 .Lscnd:
 540         lhi   %r3,0x800                 # limit reported memory size to 2GB
 541         cr    %r1,%r3
 542         jl    .Lno2gb
 543         lr    %r1,%r3
 544 .Lno2gb:
 545         xr    %r3,%r3                   # same logic
 546         ic    %r3,.Lscpa1-PARMAREA(%r4)
 547         chi   %r3,0x00
 548         jne   .Lcompmem
 549         l     %r3,.Lscpa2-PARMAREA(%r13)
 550 .Lcompmem:
 551         mr    %r2,%r1                   # mem in MB on 128-bit
 552         l     %r1,.Lonemb-.LPG1(%r13)
 553         mr    %r2,%r1                   # mem size in bytes in %r3
 554         b     .Lfchunk-.LPG1(%r13)
 555
 556 .Lpmask:
 557         .byte 0
 558 .align 8
 559 .Lpcext:.long  0x00080000,0x80000000
 560 .Lcr:
 561         .long 0x00                      # place holder for cr0
 562 .Lwaitsclp:
 563         .long 0x020A0000
 564         .long .Lsclph
 565 .Lrcp:
 566         .int 0x00120001                 # Read SCP forced code
 567 .Lrcp2:
 568         .int 0x00020001                 # Read SCP code
 569 .Lonemb:
 570         .int 0x100000
 571 .Lfchunk:
 572
 573 #
 574 # find memory chunks.
 575 #
 576         lr    %r9,%r3                    # end of mem
 577         mvc   __LC_PGM_NEW_PSW(8),.Lpcmem-.LPG1(%r13)
 578         la    %r1,1                      # test in increments of 128KB
 579         sll   %r1,17
 580         l     %r3,.Lmchunk-.LPG1(%r13)   # get pointer to memory_chunk array
 581         slr   %r4,%r4                    # set start of chunk to zero
 582         slr   %r5,%r5                    # set end of chunk to zero
 583         slr   %r6,%r6                    # set access code to zero
 584         la    %r10, MEMORY_CHUNKS        # number of chunks
 585 .Lloop:
 586         tprot 0(%r5),0                   # test protection of first byte
 587         ipm   %r7
 588         srl   %r7,28
 589         clr   %r6,%r7                    # compare cc with last access code
 590         be    .Lsame-.LPG1(%r13)
 591         b     .Lchkmem-.LPG1(%r13)
 592 .Lsame:
 593         ar    %r5,%r1                    # add 128KB to end of chunk
 594         bno   .Lloop-.LPG1(%r13)         # r1 < 0x80000000 -> loop
 595 .Lchkmem:                                # > 2GB or tprot got a program check
 596         clr   %r4,%r5                    # chunk size > 0?
 597         be    .Lchkloop-.LPG1(%r13)
 598         st    %r4,0(%r3)                 # store start address of chunk
 599         lr    %r0,%r5
 600         slr   %r0,%r4
 601         st    %r0,4(%r3)                 # store size of chunk
 602         st    %r6,8(%r3)                 # store type of chunk
 603         la    %r3,12(%r3)
 604         l     %r4,.Lmemsize-.LPG1(%r13)  # address of variable memory_size
 605         st    %r5,0(%r4)                 # store last end to memory size
 606         ahi   %r10,-1                    # update chunk number
 607 .Lchkloop:
 608         lr    %r6,%r7                    # set access code to last cc
 609         # we got an exception or we're starting a new
 610         # chunk , we must check if we should
 611         # still try to find valid memory (if we detected
 612         # the amount of available storage), and if we
 613         # have chunks left
 614         xr    %r0,%r0
 615         clr   %r0,%r9                    # did we detect memory?
 616         je    .Ldonemem                  # if not, leave
 617         chi   %r10,0                     # do we have chunks left?
 618         je    .Ldonemem
 619         alr   %r5,%r1                    # add 128KB to end of chunk
 620         lr    %r4,%r5                    # potential new chunk
 621         clr    %r5,%r9                   # should we go on?
 622         jl     .Lloop
 623 .Ldonemem:
 624         l      %r12,.Lmflags-.LPG1(%r13) # get address of machine_flags
 625 #
 626 # find out if we are running under VM
 627 #
 628         stidp  __LC_CPUID               # store cpuid
 629         tm     __LC_CPUID,0xff          # running under VM ?
 630         bno    .Lnovm-.LPG1(%r13)
 631         oi     3(%r12),1                # set VM flag
 632 .Lnovm:
 633         lh     %r0,__LC_CPUID+4         # get cpu version
 634         chi    %r0,0x7490               # running on a P/390 ?
 635         bne    .Lnop390-.LPG1(%r13)
 636         oi     3(%r12),4                # set P/390 flag
 637 .Lnop390:
 638
 639 #
 640 # find out if we have an IEEE fpu
 641 #
 642         mvc    __LC_PGM_NEW_PSW(8),.Lpcfpu-.LPG1(%r13)
 643         efpc   %r0,0                    # test IEEE extract fpc instruction
 644         oi     3(%r12),2                # set IEEE fpu flag
 645 .Lchkfpu:
 646
 647 #
 648 # find out if we have the CSP instruction
 649 #
 650        mvc    __LC_PGM_NEW_PSW(8),.Lpccsp-.LPG1(%r13)
 651        la     %r0,0
 652        lr     %r1,%r0
 653        la     %r2,4
 654        csp    %r0,%r2                   # Test CSP instruction
 655        oi     3(%r12),8                 # set CSP flag
 656 .Lchkcsp:
 657
 658 #
 659 # find out if we have the MVPG instruction
 660 #
 661        mvc    __LC_PGM_NEW_PSW(8),.Lpcmvpg-.LPG1(%r13)
 662        sr     %r0,%r0
 663        la     %r1,0
 664        la     %r2,0
 665        mvpg   %r1,%r2                   # Test CSP instruction
 666        oi     3(%r12),16                # set MVPG flag
 667 .Lchkmvpg:
 668
 669 #
 670 # find out if we have the IDTE instruction
 671 #
 672         mvc     __LC_PGM_NEW_PSW(8),.Lpcidte-.LPG1(%r13)
 673         .long   0xb2b10000              # store facility list
 674         tm      0xc8,0x08               # check bit for clearing-by-ASCE
 675         bno     .Lchkidte-.LPG1(%r13)
 676         lhi     %r1,2094
 677         lhi     %r2,0
 678         .long   0xb98e2001
 679         oi      3(%r12),0x80            # set IDTE flag
 680 .Lchkidte:
 681
 682         lpsw  .Lentry-.LPG1(13)         # jump to _stext in primary-space,
 683                                         # virtual and never return ...
 684         .align 8
 685 .Lentry:.long  0x00080000,0x80000000 + _stext
 686 .Lctl:  .long  0x04b50002               # cr0: various things
 687         .long  0                        # cr1: primary space segment table
 688         .long  .Lduct                   # cr2: dispatchable unit control table
 689         .long  0                        # cr3: instruction authorization
 690         .long  0                        # cr4: instruction authorization
 691         .long  0xffffffff               # cr5: primary-aste origin
 692         .long  0                        # cr6:  I/O interrupts
 693         .long  0                        # cr7:  secondary space segment table
 694         .long  0                        # cr8:  access registers translation
 695         .long  0                        # cr9:  tracing off
 696         .long  0                        # cr10: tracing off
 697         .long  0                        # cr11: tracing off
 698         .long  0                        # cr12: tracing off
 699         .long  0                        # cr13: home space segment table
 700         .long  0xc0000000               # cr14: machine check handling off
 701         .long  0                        # cr15: linkage stack operations
 702 .Lpcmem:.long  0x00080000,0x80000000 + .Lchkmem
 703 .Lpcfpu:.long  0x00080000,0x80000000 + .Lchkfpu
 704 .Lpccsp:.long  0x00080000,0x80000000 + .Lchkcsp
 705 .Lpcmvpg:.long 0x00080000,0x80000000 + .Lchkmvpg
 706 .Lpcidte:.long 0x00080000,0x80000000 + .Lchkidte
 707 .Lmemsize:.long memory_size
 708 .Lmchunk:.long memory_chunk
 709 .Lmflags:.long machine_flags
 710 .Lbss_bgn:  .long  __bss_start
 711 .Lbss_end:  .long  _end
 712
 713         .org PARMAREA-64
 714 .Lduct: .long 0,0,0,0,0,0,0,0
 715         .long 0,0,0,0,0,0,0,0
 716
 717 #
 718 # params at 10400 (setup.h)
 719 #
 720         .org   PARMAREA
 721         .global _pstart
 722 _pstart:
 723         .long  0,0                      # IPL_DEVICE
 724         .long  0,RAMDISK_ORIGIN         # INITRD_START
 725         .long  0,RAMDISK_SIZE           # INITRD_SIZE
 726
 727         .org   COMMAND_LINE
 728         .byte  "root=/dev/ram0 ro"
 729         .byte  0
 730         .org   0x11000
 731 .Lsccb:
 732         .hword 0x1000                   # length, one page
 733         .byte 0x00,0x00,0x00
 734         .byte 0x80                      # variable response bit set
 735 .Lsccbr:
 736         .hword 0x00                     # response code
 737 .Lscpincr1:
 738         .hword 0x00
 739 .Lscpa1:
 740         .byte 0x00
 741         .fill 89,1,0
 742 .Lscpa2:
 743         .int 0x00
 744 .Lscpincr2:
 745         .quad 0x00
 746         .fill 3984,1,0
 747         .org 0x12000
 748         .global _pend
 749 _pend:
 750
 751 #ifdef CONFIG_SHARED_KERNEL
 752         .org   0x100000
 753 #endif
 754
 755 #
 756 # startup-code, running in virtual mode
 757 #
 758         .globl _stext
 759 _stext: basr  %r13,0                    # get base
 760 .LPG2:
 761 #
 762 # Setup stack
 763 #
 764         l     %r15,.Linittu-.LPG2(%r13)
 765         mvc   __LC_CURRENT(4),__TI_task(%r15)
 766         ahi   %r15,1<<(PAGE_SHIFT+THREAD_ORDER) # init_task_union + THREAD_SIZE
 767         st    %r15,__LC_KERNEL_STACK    # set end of kernel stack
 768         ahi   %r15,-96
 769         xc    __SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15) # clear backchain
 770
 771 # check control registers
 772         stctl  %c0,%c15,0(%r15)
 773         oi     2(%r15),0x40             # enable sigp emergency signal
 774         oi     0(%r15),0x10             # switch on low address protection
 775         lctl   %c0,%c15,0(%r15)
 776
 777 #
 778         lam    0,15,.Laregs-.LPG2(%r13) # load access regs needed by uaccess
 779         l      %r14,.Lstart-.LPG2(%r13)
 780         basr   %r14,%r14                # call start_kernel
 781 #
 782 # We returned from start_kernel ?!? PANIK
 783 #
 784         basr  %r13,0
 785         lpsw  .Ldw-.(%r13)           # load disabled wait psw
 786 #
 787             .align 8
 788 .Ldw:       .long  0x000a0000,0x00000000
 789 .Linittu:   .long  init_thread_union
 790 .Lstart:    .long  start_kernel
 791 .Laregs:    .long  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
 792