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[PATCH] fast vdso implementation for CLOCK_THREAD_CPUTIME_ID

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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>
This commit is contained in:
Martin Schwidefsky
2008-12-31 15:11:42 +01:00
parent 9cfb9b3c3a
commit c742b31c03
10 changed files with 222 additions and 32 deletions
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2
arch/s390/kernel/head64.S
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@@ -87,6 +87,8 @@ startup_continue:
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
#