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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2008-12-25 13:38:36 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2008-12-25 13:38:55 +0100
commitb020632e40c3ed5e8c0c066d022672907e8401cf (patch)
treed7f805bd27e8378436fbba7e7457afbd10c22ed8 /arch/s390/kernel/vdso32/gettimeofday.S
parentfc5243d98ac2575ad14a974b3c097e9ba874c03d (diff)
[S390] introduce vdso on s390
Add a vdso to speed up gettimeofday and clock_getres/clock_gettime for CLOCK_REALTIME/CLOCK_MONOTONIC. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/kernel/vdso32/gettimeofday.S')
-rw-r--r--arch/s390/kernel/vdso32/gettimeofday.S82
1 files changed, 82 insertions, 0 deletions
diff --git a/arch/s390/kernel/vdso32/gettimeofday.S b/arch/s390/kernel/vdso32/gettimeofday.S
new file mode 100644
index 00000000000..c32f29c3d70
--- /dev/null
+++ b/arch/s390/kernel/vdso32/gettimeofday.S
@@ -0,0 +1,82 @@
+/*
+ * Userland implementation of gettimeofday() for 32 bits processes in a
+ * s390 kernel for use in the vDSO
+ *
+ * Copyright IBM Corp. 2008
+ * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License (version 2 only)
+ * as published by the Free Software Foundation.
+ */
+#include <asm/vdso.h>
+#include <asm/asm-offsets.h>
+#include <asm/unistd.h>
+
+#include <asm/vdso.h>
+#include <asm/asm-offsets.h>
+#include <asm/unistd.h>
+
+ .text
+ .align 4
+ .globl __kernel_gettimeofday
+ .type __kernel_gettimeofday,@function
+__kernel_gettimeofday:
+ .cfi_startproc
+ basr %r5,0
+0: al %r5,13f-0b(%r5) /* get &_vdso_data */
+1: ltr %r3,%r3 /* check if tz is NULL */
+ je 2f
+ mvc 0(8,%r3),__VDSO_TIMEZONE(%r5)
+2: ltr %r2,%r2 /* check if tv is NULL */
+ je 10f
+ l %r4,__VDSO_UPD_COUNT+4(%r5) /* load update counter */
+ tml %r4,0x0001 /* pending update ? loop */
+ jnz 1b
+ stck 24(%r15) /* Store TOD clock */
+ lm %r0,%r1,24(%r15)
+ s %r0,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */
+ sl %r1,__VDSO_XTIME_STAMP+4(%r5)
+ brc 3,3f
+ ahi %r0,-1
+3: mhi %r0,1000 /* cyc2ns(clock,cycle_delta) */
+ st %r0,24(%r15)
+ lhi %r0,1000
+ ltr %r1,%r1
+ mr %r0,%r0
+ jnm 4f
+ ahi %r0,1000
+4: al %r0,24(%r15)
+ srdl %r0,12
+ al %r0,__VDSO_XTIME_NSEC(%r5) /* + xtime */
+ al %r1,__VDSO_XTIME_NSEC+4(%r5)
+ brc 12,5f
+ ahi %r0,1
+5: mvc 24(4,%r15),__VDSO_XTIME_SEC+4(%r5)
+ cl %r4,__VDSO_UPD_COUNT+4(%r5) /* check update counter */
+ jne 1b
+ l %r4,24(%r15) /* get tv_sec from stack */
+ basr %r5,0
+6: ltr %r0,%r0
+ jnz 7f
+ cl %r1,11f-6b(%r5)
+ jl 8f
+7: ahi %r4,1
+ sl %r1,11f-6b(%r5)
+ brc 3,6b
+ ahi %r0,-1
+ j 6b
+8: st %r4,0(%r2) /* store tv->tv_sec */
+ ltr %r1,%r1
+ m %r0,12f-6b(%r5)
+ jnm 9f
+ al %r0,12f-6b(%r5)
+9: srl %r0,6
+ st %r0,4(%r2) /* store tv->tv_usec */
+10: slr %r2,%r2
+ br %r14
+11: .long 1000000000
+12: .long 274877907
+13: .long _vdso_data - 0b
+ .cfi_endproc
+ .size __kernel_gettimeofday,.-__kernel_gettimeofday