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linux/arch/s390/kernel/head31.S
Martin Schwidefsky 3c1fcfe229 [PATCH] Directed yield: direct yield of spinlocks for s390. 
Use the new diagnose 0x9c in the spinlock implementation for s390.  It
yields the remaining timeslice of the virtual cpu that tries to acquire a
lock to the virtual cpu that is the current holder of the lock.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-01 00:39:22 -07:00

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/*
* 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>
*
*/
#
# 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
startup:basr %r13,0 # get base
.LPG0: l %r13,0f-.LPG0(%r13)
b 0(%r13)
0: .long startup_continue
#
# params at 10400 (setup.h)
#
.org PARMAREA
.long 0,0 # IPL_DEVICE
.long 0,0 # INITRD_START
.long 0,0 # INITRD_SIZE
.org COMMAND_LINE
.byte "root=/dev/ram0 ro"
.byte 0
.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
xc __SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15) # clear backchain
l %r14,.Lipl_save_parameters-.LPG1(%r13)
basr %r14,%r14
#
# clear bss memory
#
l %r2,.Lbss_bgn-.LPG1(%r13) # start of bss
l %r3,.Lbss_end-.LPG1(%r13) # end of bss
sr %r3,%r2 # length of bss
sr %r4,%r4
sr %r5,%r5 # set src,length and pad to zero
sr %r0,%r0
mvcle %r2,%r4,0 # clear mem
jo .-4 # branch back, if not finish
l %r2,.Lrcp-.LPG1(%r13) # Read SCP forced command word
.Lservicecall:
stosm .Lpmask-.LPG1(%r13),0x01 # authorize ext interrupts
stctl %r0, %r0,.Lcr-.LPG1(%r13) # get cr0
la %r1,0x200 # set bit 22
o %r1,.Lcr-.LPG1(%r13) # or old cr0 with r1
st %r1,.Lcr-.LPG1(%r13)
lctl %r0, %r0,.Lcr-.LPG1(%r13) # load modified cr0
mvc __LC_EXT_NEW_PSW(8),.Lpcext-.LPG1(%r13) # set postcall psw
la %r1, .Lsclph-.LPG1(%r13)
a %r1,__LC_EXT_NEW_PSW+4 # set handler
st %r1,__LC_EXT_NEW_PSW+4
l %r4,.Lsccbaddr-.LPG1(%r13) # %r4 is our index for sccb stuff
lr %r1,%r4 # our sccb
.insn rre,0xb2200000,%r2,%r1 # service call
ipm %r1
srl %r1,28 # get cc code
xr %r3, %r3
chi %r1,3
be .Lfchunk-.LPG1(%r13) # leave
chi %r1,2
be .Lservicecall-.LPG1(%r13)
lpsw .Lwaitsclp-.LPG1(%r13)
.Lsclph:
lh %r1,.Lsccbr-.Lsccb(%r4)
chi %r1,0x10 # 0x0010 is the sucess code
je .Lprocsccb # let's process the sccb
chi %r1,0x1f0
bne .Lfchunk-.LPG1(%r13) # unhandled error code
c %r2, .Lrcp-.LPG1(%r13) # Did we try Read SCP forced
bne .Lfchunk-.LPG1(%r13) # if no, give up
l %r2, .Lrcp2-.LPG1(%r13) # try with Read SCP
b .Lservicecall-.LPG1(%r13)
.Lprocsccb:
lhi %r1,0
icm %r1,3,.Lscpincr1-.Lsccb(%r4) # use this one if != 0
jnz .Lscnd
lhi %r1,0x800 # otherwise report 2GB
.Lscnd:
lhi %r3,0x800 # limit reported memory size to 2GB
cr %r1,%r3
jl .Lno2gb
lr %r1,%r3
.Lno2gb:
xr %r3,%r3 # same logic
ic %r3,.Lscpa1-.Lsccb(%r4)
chi %r3,0x00
jne .Lcompmem
l %r3,.Lscpa2-.Lsccb(%r4)
.Lcompmem:
mr %r2,%r1 # mem in MB on 128-bit
l %r1,.Lonemb-.LPG1(%r13)
mr %r2,%r1 # mem size in bytes in %r3
b .Lfchunk-.LPG1(%r13)
.align 4
.Lipl_save_parameters:
.long ipl_save_parameters
.Linittu:
.long init_thread_union
.Lpmask:
.byte 0
.align 8
.Lpcext:.long 0x00080000,0x80000000
.Lcr:
.long 0x00 # place holder for cr0
.Lwaitsclp:
.long 0x010a0000,0x80000000 + .Lsclph
.Lrcp:
.int 0x00120001 # Read SCP forced code
.Lrcp2:
.int 0x00020001 # Read SCP code
.Lonemb:
.int 0x100000
.Lfchunk:
#
# find memory chunks.
#
lr %r9,%r3 # end of mem
mvc __LC_PGM_NEW_PSW(8),.Lpcmem-.LPG1(%r13)
la %r1,1 # test in increments of 128KB
sll %r1,17
l %r3,.Lmchunk-.LPG1(%r13) # get pointer to memory_chunk array
slr %r4,%r4 # set start of chunk to zero
slr %r5,%r5 # set end of chunk to zero
slr %r6,%r6 # set access code to zero
la %r10, MEMORY_CHUNKS # number of chunks
.Lloop:
tprot 0(%r5),0 # test protection of first byte
ipm %r7
srl %r7,28
clr %r6,%r7 # compare cc with last access code
be .Lsame-.LPG1(%r13)
b .Lchkmem-.LPG1(%r13)
.Lsame:
ar %r5,%r1 # add 128KB to end of chunk
bno .Lloop-.LPG1(%r13) # r1 < 0x80000000 -> loop
.Lchkmem: # > 2GB or tprot got a program check
clr %r4,%r5 # chunk size > 0?
be .Lchkloop-.LPG1(%r13)
st %r4,0(%r3) # store start address of chunk
lr %r0,%r5
slr %r0,%r4
st %r0,4(%r3) # store size of chunk
st %r6,8(%r3) # store type of chunk
la %r3,12(%r3)
l %r4,.Lmemsize-.LPG1(%r13) # address of variable memory_size
st %r5,0(%r4) # store last end to memory size
ahi %r10,-1 # update chunk number
.Lchkloop:
lr %r6,%r7 # set access code to last cc
# we got an exception or we're starting a new
# chunk , we must check if we should
# still try to find valid memory (if we detected
# the amount of available storage), and if we
# have chunks left
xr %r0,%r0
clr %r0,%r9 # did we detect memory?
je .Ldonemem # if not, leave
chi %r10,0 # do we have chunks left?
je .Ldonemem
alr %r5,%r1 # add 128KB to end of chunk
lr %r4,%r5 # potential new chunk
clr %r5,%r9 # should we go on?
jl .Lloop
.Ldonemem:
l %r12,.Lmflags-.LPG1(%r13) # get address of machine_flags
#
# find out if we are running under VM
#
stidp __LC_CPUID # store cpuid
tm __LC_CPUID,0xff # running under VM ?
bno .Lnovm-.LPG1(%r13)
oi 3(%r12),1 # set VM flag
.Lnovm:
lh %r0,__LC_CPUID+4 # get cpu version
chi %r0,0x7490 # running on a P/390 ?
bne .Lnop390-.LPG1(%r13)
oi 3(%r12),4 # set P/390 flag
.Lnop390:
#
# find out if we have an IEEE fpu
#
mvc __LC_PGM_NEW_PSW(8),.Lpcfpu-.LPG1(%r13)
efpc %r0,0 # test IEEE extract fpc instruction
oi 3(%r12),2 # set IEEE fpu flag
.Lchkfpu:
#
# find out if we have the CSP instruction
#
mvc __LC_PGM_NEW_PSW(8),.Lpccsp-.LPG1(%r13)
la %r0,0
lr %r1,%r0
la %r2,4
csp %r0,%r2 # Test CSP instruction
oi 3(%r12),8 # set CSP flag
.Lchkcsp:
#
# find out if we have the MVPG instruction
#
mvc __LC_PGM_NEW_PSW(8),.Lpcmvpg-.LPG1(%r13)
sr %r0,%r0
la %r1,0
la %r2,0
mvpg %r1,%r2 # Test CSP instruction
oi 3(%r12),16 # set MVPG flag
.Lchkmvpg:
#
# find out if we have the IDTE instruction
#
mvc __LC_PGM_NEW_PSW(8),.Lpcidte-.LPG1(%r13)
.long 0xb2b10000 # store facility list
tm 0xc8,0x08 # check bit for clearing-by-ASCE
bno .Lchkidte-.LPG1(%r13)
lhi %r1,2094
lhi %r2,0
.long 0xb98e2001
oi 3(%r12),0x80 # set IDTE flag
.Lchkidte:
#
# find out if the diag 0x9c is available
#
mvc __LC_PGM_NEW_PSW(8),.Lpcdiag9c-.LPG1(%r13)
stap __LC_CPUID+4 # store cpu address
lh %r1,__LC_CPUID+4
diag %r1,0,0x9c # test diag 0x9c
oi 2(%r12),1 # set diag9c flag
.Lchkdiag9c:
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 0xffffffff # 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
.Lduct: .long 0,0,0,0,0,0,0,0
.long 0,0,0,0,0,0,0,0
.Lpcmem:.long 0x00080000,0x80000000 + .Lchkmem
.Lpcfpu:.long 0x00080000,0x80000000 + .Lchkfpu
.Lpccsp:.long 0x00080000,0x80000000 + .Lchkcsp
.Lpcmvpg:.long 0x00080000,0x80000000 + .Lchkmvpg
.Lpcidte:.long 0x00080000,0x80000000 + .Lchkidte
.Lpcdiag9c:.long 0x00080000,0x80000000 + .Lchkdiag9c
.Lmemsize:.long memory_size
.Lmchunk:.long memory_chunk
.Lmflags:.long machine_flags
.Lbss_bgn: .long __bss_start
.Lbss_end: .long _end
.Lparmaddr: .long PARMAREA
.Lsccbaddr: .long .Lsccb
.globl ipl_schib
ipl_schib:
.rept 13
.long 0
.endr
.globl ipl_flags
ipl_flags:
.long 0
.globl ipl_devno
ipl_devno:
.word 0
.org 0x12000
.globl s390_readinfo_sccb
s390_readinfo_sccb:
.Lsccb:
.hword 0x1000 # length, one page
.byte 0x00,0x00,0x00
.byte 0x80 # variable response bit set
.Lsccbr:
.hword 0x00 # response code
.Lscpincr1:
.hword 0x00
.Lscpa1:
.byte 0x00
.fill 89,1,0
.Lscpa2:
.int 0x00
.Lscpincr2:
.quad 0x00
.fill 3984,1,0
.org 0x13000
#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
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