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8f75582a2f
linux/arch/s390/boot/head.S
Vasily Gorbik 8f75582a2f s390: remove decompressor's head.S 
Decompressor's head.S provided "data mover" sole purpose of which has
been to safely move uncompressed kernel at 0x100000 and jump to it.

With current bzImage layout entire decompressor's code guaranteed to be
in a safe location under 0x100000, and hence could not be overwritten
during kernel move. For that reason head.S could be replaced with simple
memmove function. To do so introduce early boot code phase which is
executed from arch/s390/boot/head.S after "verify_facilities" and takes
care of optional kernel image decompression and transition to it.

Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-10-09 11:21:02 +02:00

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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright IBM Corp. 1999, 2010
*
* Author(s): Hartmut Penner <hp@de.ibm.com>
* Martin Schwidefsky <schwidefsky@de.ibm.com>
* Rob van der Heij <rvdhei@iae.nl>
* Heiko Carstens <heiko.carstens@de.ibm.com>
*
* 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/init.h>
#include <linux/linkage.h>
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
#include <asm/page.h>
#include <asm/ptrace.h>
#define ARCH_OFFSET 4
__HEAD
#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 0x200 = 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 0x1a0
.quad 0,iplstart
.org 0x200
#
# subroutine to wait for end I/O
#
.Lirqwait:
mvc __LC_IO_NEW_PSW(16),.Lnewpsw # set up IO interrupt psw
lpsw .Lwaitpsw
.Lioint:
br %r14
.align 8
.Lnewpsw:
.quad 0x0000000080000000,.Lioint
.Lwaitpsw:
.long 0x020a0000,0x80000000+.Lioint
#
# subroutine for loading cards from the reader
#
.Lloader:
la %r4,0(%r14)
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:
bas %r14,.Lirqwait
c %r1,__LC_SUBCHANNEL_ID # 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 %r4 # 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
.align 8
.Lccws: .rept 19
.long 0x02600050,0x00000000
.endr
.long 0x02200050,0x00000000
iplstart:
mvi __LC_AR_MODE_ID,1 # set esame flag
slr %r0,%r0 # set cpuid to zero
lhi %r1,2 # mode 2 = esame (dump)
sigp %r1,%r0,0x12 # switch to esame mode
bras %r13,0f
.fill 16,4,0x0
0: lmh %r0,%r15,0(%r13) # clear high-order half of gprs
sam31 # switch to 31 bit addressing mode
lh %r1,__LC_SUBCHANNEL_ID # test if subchannel number
bct %r1,.Lnoload # is valid
l %r1,__LC_SUBCHANNEL_ID # 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
#
.Lagain1:
l %r2,.Linitrd # ramdisk loc. is temp
bas %r14,.Lloader # load parameter file
ltr %r2,%r2 # got anything ?
bz .Lnopf
chi %r2,895
bnh .Lnotrunc
la %r2,895
.Lnotrunc:
l %r4,.Linitrd
clc 0(3,%r4),.L_hdr # if it is HDRx
bz .Lagain1 # skip dataset header
clc 0(3,%r4),.L_eof # if it is EOFx
bz .Lagain1 # skip dateset trailer
la %r5,0(%r4,%r2)
lr %r3,%r2
la %r3,COMMAND_LINE-PARMAREA(%r12) # load adr. of command line
mvc 0(256,%r3),0(%r4)
mvc 256(256,%r3),256(%r4)
mvc 512(256,%r3),512(%r4)
mvc 768(122,%r3),768(%r4)
slr %r0,%r0
b .Lcntlp
.Ldelspc:
ic %r0,0(%r2,%r3)
chi %r0,0x20 # is it a space ?
be .Lcntlp
ahi %r2,1
b .Leolp
.Lcntlp:
brct %r2,.Ldelspc
.Leolp:
slr %r0,%r0
stc %r0,0(%r2,%r3) # terminate buffer
.Lnopf:
#
# load ramdisk from ipl device
#
.Lagain2:
l %r2,.Linitrd # addr of ramdisk
st %r2,INITRD_START+ARCH_OFFSET-PARMAREA(%r12)
bas %r14,.Lloader # load ramdisk
st %r2,INITRD_SIZE+ARCH_OFFSET-PARMAREA(%r12) # store size of rd
ltr %r2,%r2
bnz .Lrdcont
st %r2,INITRD_START+ARCH_OFFSET-PARMAREA(%r12) # no ramdisk found
.Lrdcont:
l %r2,.Linitrd
clc 0(3,%r2),.L_hdr # skip HDRx and EOFx
bz .Lagain2
clc 0(3,%r2),.L_eof
bz .Lagain2
#
# reset files in VM reader
#
stidp .Lcpuid # store cpuid
tm .Lcpuid,0xff # running VM ?
bno .Lnoreset
la %r2,.Lreset
lhi %r3,26
diag %r2,%r3,8
la %r5,.Lirb
stsch 0(%r5) # check if irq is pending
tm 30(%r5),0x0f # by verifying if any of the
bnz .Lwaitforirq # activity or status control
tm 31(%r5),0xff # bits is set in the schib
bz .Lnoreset
.Lwaitforirq:
bas %r14,.Lirqwait # wait for IO interrupt
c %r1,__LC_SUBCHANNEL_ID # compare subchannel number
bne .Lwaitforirq
la %r5,.Lirb
tsch 0(%r5)
.Lnoreset:
b .Lnoload
#
# everything loaded, go for it
#
.Lnoload:
l %r1,.Lstartup
br %r1
.Linitrd:.long _end # default address of initrd
.Lparm: .long PARMAREA
.Lstartup: .long startup
.Lreset:.byte 0xc3,0xc8,0xc1,0xd5,0xc7,0xc5,0x40,0xd9,0xc4,0xd9,0x40
.byte 0xc1,0xd3,0xd3,0x40,0xd2,0xc5,0xc5,0xd7,0x40,0xd5,0xd6
.byte 0xc8,0xd6,0xd3,0xc4 # "change rdr all keep nohold"
.L_eof: .long 0xc5d6c600 /* C'EOF' */
.L_hdr: .long 0xc8c4d900 /* C'HDR' */
.align 8
.Lcpuid:.fill 8,1,0
#
# startup-code at 0x10000, running in absolute addressing mode
# this is called either by the ipl loader or directly by PSW restart
# or linload or SALIPL
#
.org 0x10000
ENTRY(startup)
j .Lep_startup_normal
.org EP_OFFSET
#
# This is a list of s390 kernel entry points. At address 0x1000f the number of
# valid entry points is stored.
#
# IMPORTANT: Do not change this table, it is s390 kernel ABI!
#
.ascii EP_STRING
.byte 0x00,0x01
#
# kdump startup-code at 0x10010, running in 64 bit absolute addressing mode
#
.org 0x10010
ENTRY(startup_kdump)
j .Lep_startup_kdump
.Lep_startup_normal:
mvi __LC_AR_MODE_ID,1 # set esame flag
slr %r0,%r0 # set cpuid to zero
lhi %r1,2 # mode 2 = esame (dump)
sigp %r1,%r0,0x12 # switch to esame mode
bras %r13,0f
.fill 16,4,0x0
0: lmh %r0,%r15,0(%r13) # clear high-order half of gprs
sam64 # switch to 64 bit addressing mode
basr %r13,0 # get base
.LPG0:
xc 0x200(256),0x200 # partially clear lowcore
xc 0x300(256),0x300
xc 0xe00(256),0xe00
xc 0xf00(256),0xf00
lctlg %c0,%c15,0x200(%r0) # initialize control registers
stcke __LC_BOOT_CLOCK
mvc __LC_LAST_UPDATE_CLOCK(8),__LC_BOOT_CLOCK+1
spt 6f-.LPG0(%r13)
mvc __LC_LAST_UPDATE_TIMER(8),6f-.LPG0(%r13)
l %r15,.Lstack-.LPG0(%r13)
brasl %r14,verify_facilities
brasl %r14,startup_kernel
.Lstack:
.long 0x8000 + THREAD_SIZE - STACK_FRAME_OVERHEAD
.align 8
6: .long 0x7fffffff,0xffffffff
#include "head_kdump.S"
#
# params at 10400 (setup.h)
#
.org PARMAREA
.long 0,0 # IPL_DEVICE
.long 0,0 # INITRD_START
.long 0,0 # INITRD_SIZE
.long 0,0 # OLDMEM_BASE
.long 0,0 # OLDMEM_SIZE
.org COMMAND_LINE
.byte "root=/dev/ram0 ro"
.byte 0
.org 0x11000
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