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linux-next/arch/s390/kernel/head64.S
Martin Schwidefsky c742b31c03 [PATCH] fast vdso implementation for CLOCK_THREAD_CPUTIME_ID
The extract cpu time instruction (ectg) instruction allows the user
process to get the current thread cputime without calling into the
kernel. The code that uses the instruction needs to switch to the
access registers mode to get access to the per-cpu info page that
contains the two base values that are needed to calculate the current
cputime from the CPU timer with the ectg instruction.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-12-31 15:11:49 +01:00

178 lines
4.7 KiB
ArmAsm

/*
* arch/s390/kernel/head64.S
*
* Copyright (C) IBM Corp. 1999,2006
*
* 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: sll %r13,1 # remove high order bit
srl %r13,1
#ifdef CONFIG_ZFCPDUMP
# check if we have been ipled using zfcp dump:
tm 0xb9,0x01 # test if subchannel is enabled
jno .nodump # subchannel disabled
l %r1,0xb8
la %r5,.Lipl_schib-.LPG1(%r13)
stsch 0(%r5) # get schib of subchannel
jne .nodump # schib not available
tm 5(%r5),0x01 # devno valid?
jno .nodump
tm 4(%r5),0x80 # qdio capable device?
jno .nodump
l %r2,20(%r0) # address of ipl parameter block
lhi %r3,0
ic %r3,0x148(%r2) # get opt field
chi %r3,0x20 # load with dump?
jne .nodump
# store all prefix registers in case of load with dump:
la %r7,0 # base register for 0 page
la %r8,0 # first cpu
l %r11,.Lpref_arr_ptr-.LPG1(%r13) # address of prefix array
ahi %r11,4 # skip boot cpu
lr %r12,%r11
ahi %r12,(CONFIG_NR_CPUS*4) # end of prefix array
stap .Lcurrent_cpu+2-.LPG1(%r13) # store current cpu addr
1:
cl %r8,.Lcurrent_cpu-.LPG1(%r13) # is ipl cpu ?
je 4f # if yes get next cpu
2:
lr %r9,%r7
sigp %r9,%r8,0x9 # stop & store status of cpu
brc 8,3f # accepted
brc 4,4f # status stored: next cpu
brc 2,2b # busy: try again
brc 1,4f # not op: next cpu
3:
mvc 0(4,%r11),264(%r7) # copy prefix register to prefix array
ahi %r11,4 # next element in prefix array
clr %r11,%r12
je 5f # no more space in prefix array
4:
ahi %r8,1 # next cpu (r8 += 1)
cl %r8,.Llast_cpu-.LPG1(%r13) # is last possible cpu ?
jl 1b # jump if not last cpu
5:
lhi %r1,2 # mode 2 = esame (dump)
j 6f
.align 4
.Lipl_schib:
.rept 13
.long 0
.endr
.nodump:
lhi %r1,1 # mode 1 = esame (normal ipl)
6:
#else
lhi %r1,1 # mode 1 = esame (normal ipl)
#endif /* CONFIG_ZFCPDUMP */
mvi __LC_AR_MODE_ID,1 # set esame flag
slr %r0,%r0 # set cpuid to zero
sigp %r1,%r0,0x12 # switch to esame mode
sam64 # switch to 64 bit mode
lctlg %c0,%c15,.Lctl-.LPG1(%r13) # load control registers
lg %r12,.Lparmaddr-.LPG1(%r13) # pointer to parameter area
# move IPL device to lowcore
mvc __LC_IPLDEV(4),IPL_DEVICE+4-PARMAREA(%r12)
lghi %r0,__LC_PASTE
stg %r0,__LC_VDSO_PER_CPU
#
# Setup stack
#
larl %r15,init_thread_union
lg %r14,__TI_task(%r15) # cache current in lowcore
stg %r14,__LC_CURRENT
aghi %r15,1<<(PAGE_SHIFT+THREAD_ORDER) # init_task_union + THREAD_SIZE
stg %r15,__LC_KERNEL_STACK # set end of kernel stack
aghi %r15,-160
#
# Save ipl parameters, clear bss memory, initialize storage key for kernel pages,
# and create a kernel NSS if the SAVESYS= parm is defined
#
brasl %r14,startup_init
lpswe .Lentry-.LPG1(13) # jump to _stext in primary-space,
# virtual and never return ...
.align 16
.Lentry:.quad 0x0000000180000000,_stext
.Lctl: .quad 0x04350002 # cr0: various things
.quad 0 # cr1: primary space segment table
.quad .Lduct # cr2: dispatchable unit control table
.quad 0 # cr3: instruction authorization
.quad 0 # cr4: instruction authorization
.quad .Lduct # cr5: primary-aste origin
.quad 0 # cr6: I/O interrupts
.quad 0 # cr7: secondary space segment table
.quad 0 # cr8: access registers translation
.quad 0 # cr9: tracing off
.quad 0 # cr10: tracing off
.quad 0 # cr11: tracing off
.quad 0 # cr12: tracing off
.quad 0 # cr13: home space segment table
.quad 0xc0000000 # cr14: machine check handling off
.quad 0 # cr15: linkage stack operations
.Lpcmsk:.quad 0x0000000180000000
.L4malign:.quad 0xffffffffffc00000
.Lscan2g:.quad 0x80000000 + 0x20000 - 8 # 2GB + 128K - 8
.Lnop: .long 0x07000700
#ifdef CONFIG_ZFCPDUMP
.Lcurrent_cpu:
.long 0x0
.Llast_cpu:
.long 0x0000ffff
.Lpref_arr_ptr:
.long zfcpdump_prefix_array
#endif /* CONFIG_ZFCPDUMP */
.Lparmaddr:
.quad PARMAREA
.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
stctg %c0,%c15,0(%r15)
oi 6(%r15),0x40 # enable sigp emergency signal
oi 4(%r15),0x10 # switch on low address proctection
lctlg %c0,%c15,0(%r15)
lam 0,15,.Laregs-.LPG3(%r13) # load acrs needed by uaccess
brasl %r14,start_kernel # go to C code
#
# We returned from start_kernel ?!? PANIK
#
basr %r13,0
lpswe .Ldw-.(%r13) # load disabled wait psw
.align 8
.Ldw: .quad 0x0002000180000000,0x0000000000000000
.Laregs:.long 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0