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[S390] Use diag260 for memory size detection.

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Avoid the tprot loop if diag260 works and reports that there are no
holes in memory. The tprot instruction can lead to a significant delay
in the ipl process if the virtual guest has a lot of memory and the
host is under memory pressure.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Heiko Carstens 2006-12-04 15:40:42 +01:00 committed by Martin Schwidefsky
parent 29b08d2bae
commit d57de5a367
1 changed files with 15 additions and 2 deletions
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17
arch/s390/kernel/head64.S
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@ -70,7 +70,22 @@ startup_continue:
sgr %r5,%r5 # set src,length and pad to zero
mvcle %r2,%r4,0 # clear mem
jo .-4 # branch back, if not finish
# set program check new psw mask
mvc __LC_PGM_NEW_PSW(8),.Lpcmsk-.LPG1(%r13)
larl %r1,.Lslowmemdetect # set program check address
stg %r1,__LC_PGM_NEW_PSW+8
lghi %r1,0xc
diag %r0,%r1,0x260 # get memory size of virtual machine
cgr %r0,%r1 # different? -> old detection routine
jne .Lslowmemdetect
aghi %r1,1 # size is one more than end
larl %r2,memory_chunk
stg %r1,8(%r2) # store size of chunk
larl %r2,memory_size
stg %r1,0(%r2) # set memory size
j .Ldonemem
.Lslowmemdetect:
l %r2,.Lrcp-.LPG1(%r13) # Read SCP forced command word
.Lservicecall:
stosm .Lpmask-.LPG1(%r13),0x01 # authorize ext interrupts
@ -139,8 +154,6 @@ startup_continue:
.int 0x100000
.Lfchunk:
# set program check new psw mask
mvc __LC_PGM_NEW_PSW(8),.Lpcmsk-.LPG1(%r13)
#
# find memory chunks.