linux/arch/s390/kernel/head31.S
Heiko Carstens c58d92b233 [S390] Remove initial kernel stack backchain initialization.
Early init code clears the backchain of the initial kernel stack frame.
This is not necessary since it is pre initialized with zeros. Plus it
was broken on 64 bit since it cleared only four of eight bytes.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-12-25 13:39:13 +01:00

106 lines
2.8 KiB
ArmAsm

/*
* arch/s390/kernel/head31.S
*
* Copyright (C) IBM Corp. 2005,2006
*
* 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>
*
*/
.org 0x11000
startup_continue:
basr %r13,0 # get base
.LPG1:
mvi __LC_AR_MODE_ID,0 # set ESA flag (mode 0)
lctl %c0,%c15,.Lctl-.LPG1(%r13) # load control registers
l %r12,.Lparmaddr-.LPG1(%r13) # pointer to parameter area
# move IPL device to lowcore
mvc __LC_IPLDEV(4),IPL_DEVICE-PARMAREA(%r12)
#
# Setup stack
#
l %r15,.Linittu-.LPG1(%r13)
mvc __LC_CURRENT(4),__TI_task(%r15)
ahi %r15,1<<(PAGE_SHIFT+THREAD_ORDER) # init_task_union+THREAD_SIZE
st %r15,__LC_KERNEL_STACK # set end of kernel stack
ahi %r15,-96
#
# Save ipl parameters, clear bss memory, initialize storage key for kernel pages,
# and create a kernel NSS if the SAVESYS= parm is defined
#
l %r14,.Lstartup_init-.LPG1(%r13)
basr %r14,%r14
lpsw .Lentry-.LPG1(13) # jump to _stext in primary-space,
# virtual and never return ...
.align 8
.Lentry:.long 0x00080000,0x80000000 + _stext
.Lctl: .long 0x04b50002 # cr0: various things
.long 0 # cr1: primary space segment table
.long .Lduct # cr2: dispatchable unit control table
.long 0 # cr3: instruction authorization
.long 0 # cr4: instruction authorization
.long .Lduct # cr5: primary-aste origin
.long 0 # cr6: I/O interrupts
.long 0 # cr7: secondary space segment table
.long 0 # cr8: access registers translation
.long 0 # cr9: tracing off
.long 0 # cr10: tracing off
.long 0 # cr11: tracing off
.long 0 # cr12: tracing off
.long 0 # cr13: home space segment table
.long 0xc0000000 # cr14: machine check handling off
.long 0 # cr15: linkage stack operations
.Lmchunk:.long memory_chunk
.Lbss_bgn: .long __bss_start
.Lbss_end: .long _end
.Lparmaddr: .long PARMAREA
.Linittu: .long init_thread_union
.Lstartup_init:
.long startup_init
.align 64
.Lduct: .long 0,0,0,0,.Lduald,0,0,0
.long 0,0,0,0,0,0,0,0
.align 128
.Lduald:.rept 8
.long 0x80000000,0,0,0 # invalid access-list entries
.endr
.org 0x12000
.globl _ehead
_ehead:
#ifdef CONFIG_SHARED_KERNEL
.org 0x100000
#endif
#
# startup-code, running in absolute addressing mode
#
.globl _stext
_stext: basr %r13,0 # get base
.LPG3:
# check control registers
stctl %c0,%c15,0(%r15)
oi 2(%r15),0x40 # enable sigp emergency signal
oi 0(%r15),0x10 # switch on low address protection
lctl %c0,%c15,0(%r15)
#
lam 0,15,.Laregs-.LPG3(%r13) # load access regs needed by uaccess
l %r14,.Lstart-.LPG3(%r13)
basr %r14,%r14 # call start_kernel
#
# We returned from start_kernel ?!? PANIK
#
basr %r13,0
lpsw .Ldw-.(%r13) # load disabled wait psw
#
.align 8
.Ldw: .long 0x000a0000,0x00000000
.Lstart:.long start_kernel
.Laregs:.long 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0