head.s

LINUX 2.6.17.4的源码

/*
 *  arch/s390/kernel/head.S
 *
 * (C) Copyright IBM Corp. 1999, 2005
 *
 *    Author(s): Hartmut Penner <[e-mail]>
 *		 Martin Schwidefsky <[e-mail]>
 *		 Rob van der Heij <[e-mail]>
 *		 Heiko Carstens <[e-mail]>
 *
 * There are 5 different IPL methods
 *  1) load the image directly into ram at address 0 and do an PSW restart
 *  2) linload will load the image from address 0x10000 to memory 0x10000
 *     and start the code thru LPSW 0x0008000080010000 (VM only, deprecated)
 *  3) generate the tape ipl header, store the generated image on a tape
 *     and ipl from it
 *     In case of SL tape you need to IPL 5 times to get past VOL1 etc
 *  4) generate the vm reader ipl header, move the generated image to the
 *     VM reader (use option NOH!) and do a ipl from reader (VM only)
 *  5) direct call of start by the SALIPL loader
 *  We use the cpuid to distinguish between VM and native ipl
 *  params for kernel are pushed to 0x10400 (see setup.h)
 *
 */

#include <linux/config.h>
#include <asm/setup.h>
#include <asm/lowcore.h>
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
#include <asm/page.h>

#ifdef CONFIG_64BIT
#define ARCH_OFFSET	4
#else
#define ARCH_OFFSET	0
#endif

#ifndef CONFIG_IPL
        .org   0
        .long  0x00080000,0x80000000+startup   # Just a restart PSW
#else
#ifdef CONFIG_IPL_TAPE
#define IPL_BS 1024
        .org   0
        .long  0x00080000,0x80000000+iplstart  # The first 24 bytes are loaded
        .long  0x27000000,0x60000001           # by ipl to addresses 0-23.
        .long  0x02000000,0x20000000+IPL_BS    # (a PSW and two CCWs).
        .long  0x00000000,0x00000000           # external old psw
        .long  0x00000000,0x00000000           # svc old psw
        .long  0x00000000,0x00000000           # program check old psw
        .long  0x00000000,0x00000000           # machine check old psw
        .long  0x00000000,0x00000000           # io old psw
        .long  0x00000000,0x00000000
        .long  0x00000000,0x00000000
        .long  0x00000000,0x00000000
        .long  0x000a0000,0x00000058           # external new psw
        .long  0x000a0000,0x00000060           # svc new psw
        .long  0x000a0000,0x00000068           # program check new psw
        .long  0x000a0000,0x00000070           # machine check new psw
        .long  0x00080000,0x80000000+.Lioint   # io new psw

        .org   0x100
#
# subroutine for loading from tape
# Paramters:	
#  R1 = device number
#  R2 = load address
.Lloader:	
        st    %r14,.Lldret
        la    %r3,.Lorbread                    # r3 = address of orb 
	la    %r5,.Lirb                        # r5 = address of irb
        st    %r2,.Lccwread+4                  # initialize CCW data addresses
        lctl  %c6,%c6,.Lcr6               
        slr   %r2,%r2
.Lldlp:
        la    %r6,3                            # 3 retries
.Lssch:
        ssch  0(%r3)                           # load chunk of IPL_BS bytes
        bnz   .Llderr
.Lw4end:
        bas   %r14,.Lwait4io
        tm    8(%r5),0x82                      # do we have a problem ?
        bnz   .Lrecov
        slr   %r7,%r7
        icm   %r7,3,10(%r5)                    # get residual count
        lcr   %r7,%r7
        la    %r7,IPL_BS(%r7)                  # IPL_BS-residual=#bytes read
        ar    %r2,%r7                          # add to total size
        tm    8(%r5),0x01                      # found a tape mark ?
        bnz   .Ldone
        l     %r0,.Lccwread+4                  # update CCW data addresses
        ar    %r0,%r7
        st    %r0,.Lccwread+4                
        b     .Lldlp
.Ldone:
        l     %r14,.Lldret
        br    %r14                             # r2 contains the total size
.Lrecov:
        bas   %r14,.Lsense                     # do the sensing
        bct   %r6,.Lssch                       # dec. retry count & branch
        b     .Llderr
#
# Sense subroutine
#
.Lsense:
        st    %r14,.Lsnsret
        la    %r7,.Lorbsense              
        ssch  0(%r7)                           # start sense command
        bnz   .Llderr
        bas   %r14,.Lwait4io
        l     %r14,.Lsnsret
        tm    8(%r5),0x82                      # do we have a problem ?
        bnz   .Llderr
        br    %r14
#
# Wait for interrupt subroutine
#
.Lwait4io:
        lpsw  .Lwaitpsw                 
.Lioint:
        c     %r1,0xb8                         # compare subchannel number
        bne   .Lwait4io
        tsch  0(%r5)
        slr   %r0,%r0
        tm    8(%r5),0x82                      # do we have a problem ?
        bnz   .Lwtexit
        tm    8(%r5),0x04                      # got device end ?
        bz    .Lwait4io
.Lwtexit:
        br    %r14
.Llderr:
        lpsw  .Lcrash              

        .align 8
.Lorbread:
	.long  0x00000000,0x0080ff00,.Lccwread
        .align 8
.Lorbsense:
        .long  0x00000000,0x0080ff00,.Lccwsense
        .align 8
.Lccwread:
        .long  0x02200000+IPL_BS,0x00000000
.Lccwsense:
        .long  0x04200001,0x00000000
.Lwaitpsw:
	.long  0x020a0000,0x80000000+.Lioint

.Lirb:	.long  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.Lcr6:  .long  0xff000000
        .align 8
.Lcrash:.long  0x000a0000,0x00000000
.Lldret:.long  0
.Lsnsret: .long 0
#endif  /* CONFIG_IPL_TAPE */

#ifdef CONFIG_IPL_VM
#define IPL_BS 0x730
        .org   0
        .long  0x00080000,0x80000000+iplstart  # The first 24 bytes are loaded
        .long  0x02000018,0x60000050           # by ipl to addresses 0-23.
        .long  0x02000068,0x60000050           # (a PSW and two CCWs).
        .fill  80-24,1,0x40                    # bytes 24-79 are discarded !!
        .long  0x020000f0,0x60000050           # The next 160 byte are loaded
        .long  0x02000140,0x60000050           # to addresses 0x18-0xb7
        .long  0x02000190,0x60000050           # They form the continuation
        .long  0x020001e0,0x60000050           # of the CCW program started
        .long  0x02000230,0x60000050           # by ipl and load the range
        .long  0x02000280,0x60000050           # 0x0f0-0x730 from the image
        .long  0x020002d0,0x60000050           # to the range 0x0f0-0x730
        .long  0x02000320,0x60000050           # in memory. At the end of
        .long  0x02000370,0x60000050           # the channel program the PSW
        .long  0x020003c0,0x60000050           # at location 0 is loaded.
        .long  0x02000410,0x60000050           # Initial processing starts
        .long  0x02000460,0x60000050           # at 0xf0 = iplstart.
        .long  0x020004b0,0x60000050
        .long  0x02000500,0x60000050
        .long  0x02000550,0x60000050
        .long  0x020005a0,0x60000050
        .long  0x020005f0,0x60000050
        .long  0x02000640,0x60000050
        .long  0x02000690,0x60000050
        .long  0x020006e0,0x20000050

        .org   0xf0
#
# subroutine for loading cards from the reader
#
.Lloader:	
	la    %r3,.Lorb                        # r2 = address of orb into r2
	la    %r5,.Lirb                        # r4 = address of irb
        la    %r6,.Lccws              
        la    %r7,20
.Linit:
        st    %r2,4(%r6)                       # initialize CCW data addresses
        la    %r2,0x50(%r2)
        la    %r6,8(%r6)
        bct   7,.Linit

        lctl  %c6,%c6,.Lcr6                    # set IO subclass mask
	slr   %r2,%r2
.Lldlp:
        ssch  0(%r3)                           # load chunk of 1600 bytes
        bnz   .Llderr
.Lwait4irq:
        mvc   0x78(8),.Lnewpsw                 # set up IO interrupt psw
        lpsw  .Lwaitpsw              
.Lioint:
        c     %r1,0xb8                         # compare subchannel number
	bne   .Lwait4irq
	tsch  0(%r5)

	slr   %r0,%r0
	ic    %r0,8(%r5)                       # get device status
	chi   %r0,8                            # channel end ?
	be    .Lcont
	chi   %r0,12                           # channel end + device end ?
	be    .Lcont

        l     %r0,4(%r5)
        s     %r0,8(%r3)                       # r0/8 = number of ccws executed
        mhi   %r0,10                           # *10 = number of bytes in ccws
        lh    %r3,10(%r5)                      # get residual count
        sr    %r0,%r3                          # #ccws*80-residual=#bytes read
	ar    %r2,%r0
	
        br    %r14                             # r2 contains the total size

.Lcont:
	ahi   %r2,0x640                        # add 0x640 to total size
        la    %r6,.Lccws             
        la    %r7,20
.Lincr:
        l     %r0,4(%r6)                       # update CCW data addresses
        ahi   %r0,0x640
        st    %r0,4(%r6)
        ahi   %r6,8
        bct   7,.Lincr

        b     .Lldlp
.Llderr:
        lpsw  .Lcrash              

        .align 8
.Lorb:	.long  0x00000000,0x0080ff00,.Lccws
.Lirb:	.long  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.Lcr6:  .long  0xff000000
.Lloadp:.long  0,0
        .align 8
.Lcrash:.long  0x000a0000,0x00000000
.Lnewpsw:
        .long  0x00080000,0x80000000+.Lioint
.Lwaitpsw:
        .long  0x020a0000,0x80000000+.Lioint

        .align 8
.Lccws: .rept  19
        .long  0x02600050,0x00000000
        .endr
        .long  0x02200050,0x00000000
#endif  /* CONFIG_IPL_VM */

iplstart:
        lh    %r1,0xb8                         # test if subchannel number
        bct   %r1,.Lnoload                     #  is valid
	l     %r1,0xb8                         # load ipl subchannel number
        la    %r2,IPL_BS                       # load start address
        bas   %r14,.Lloader                    # load rest of ipl image
        l     %r12,.Lparm                      # pointer to parameter area
        st    %r1,IPL_DEVICE+ARCH_OFFSET-PARMAREA(%r12) # save ipl device number

#
# load parameter file from ipl device
#