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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2006-09-30 23:27:45 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-01 00:39:22 -0700
commit3c1fcfe229e99752c74efb945a4a3f560be04204 (patch)
tree44085d9b599e06a92426141811a6f712beac17aa /arch/s390/kernel/head64.S
parentcdc39363d33506b0e067d41fc91f89d186bdf7f7 (diff)
downloadlinux-2.6.34-ux500-3c1fcfe229e99752c74efb945a4a3f560be04204.tar.gz
[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>
Diffstat (limited to 'arch/s390/kernel/head64.S')
-rw-r--r--arch/s390/kernel/head64.S11
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/s390/kernel/head64.S b/arch/s390/kernel/head64.S
index 48998d50b00..b30e5897cdf 100644
--- a/arch/s390/kernel/head64.S
+++ b/arch/s390/kernel/head64.S
@@ -251,6 +251,17 @@ startup_continue:
0:
#
+# find out if the diag 0x9c is available
+#
+ la %r1,0f-.LPG1(%r13) # set program check address
+ stg %r1,__LC_PGM_NEW_PSW+8
+ stap __LC_CPUID+4 # store cpu address
+ lh %r1,__LC_CPUID+4
+ diag %r1,0,0x9c # test diag 0x9c
+ oi 6(%r12),1 # set diag9c flag
+0:
+
+#
# find out if we have the MVCOS instruction
#
la %r1,0f-.LPG1(%r13) # set program check address