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-rw-r--r--arch/s390/kernel/vdso32/clock_gettime.S128
1 files changed, 128 insertions, 0 deletions
diff --git a/arch/s390/kernel/vdso32/clock_gettime.S b/arch/s390/kernel/vdso32/clock_gettime.S
new file mode 100644
index 000000000000..4a98909a8310
--- /dev/null
+++ b/arch/s390/kernel/vdso32/clock_gettime.S
@@ -0,0 +1,128 @@
+/*
+ * Userland implementation of clock_gettime() 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>
+
+ .text
+ .align 4
+ .globl __kernel_clock_gettime
+ .type __kernel_clock_gettime,@function
+__kernel_clock_gettime:
+ .cfi_startproc
+ basr %r5,0
+0: al %r5,21f-0b(%r5) /* get &_vdso_data */
+ chi %r2,CLOCK_REALTIME
+ je 10f
+ chi %r2,CLOCK_MONOTONIC
+ jne 19f
+
+ /* CLOCK_MONOTONIC */
+ ltr %r3,%r3
+ jz 9f /* tp == NULL */
+1: 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 3,2f
+ ahi %r0,-1
+2: mhi %r0,1000 /* cyc2ns(clock,cycle_delta) */
+ lr %r2,%r0
+ lhi %r0,1000
+ ltr %r1,%r1
+ mr %r0,%r0
+ jnm 3f
+ ahi %r0,1000
+3: alr %r0,%r2
+ srdl %r0,12
+ al %r0,__VDSO_XTIME_NSEC(%r5) /* + xtime */
+ al %r1,__VDSO_XTIME_NSEC+4(%r5)
+ brc 12,4f
+ ahi %r0,1
+4: l %r2,__VDSO_XTIME_SEC+4(%r5)
+ al %r0,__VDSO_WTOM_NSEC(%r5) /* + wall_to_monotonic */
+ al %r1,__VDSO_WTOM_NSEC+4(%r5)
+ brc 12,5f
+ ahi %r0,1
+5: al %r2,__VDSO_WTOM_SEC+4(%r5)
+ cl %r4,__VDSO_UPD_COUNT+4(%r5) /* check update counter */
+ jne 1b
+ basr %r5,0
+6: ltr %r0,%r0
+ jnz 7f
+ cl %r1,20f-6b(%r5)
+ jl 8f
+7: ahi %r2,1
+ sl %r1,20f-6b(%r5)
+ brc 3,6b
+ ahi %r0,-1
+ j 6b
+8: st %r2,0(%r3) /* store tp->tv_sec */
+ st %r1,4(%r3) /* store tp->tv_nsec */
+9: lhi %r2,0
+ br %r14
+
+ /* CLOCK_REALTIME */
+10: ltr %r3,%r3 /* tp == NULL */
+ jz 18f
+11: l %r4,__VDSO_UPD_COUNT+4(%r5) /* load update counter */
+ tml %r4,0x0001 /* pending update ? loop */
+ jnz 11b
+ 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 3,12f
+ ahi %r0,-1
+12: mhi %r0,1000 /* cyc2ns(clock,cycle_delta) */
+ lr %r2,%r0
+ lhi %r0,1000
+ ltr %r1,%r1
+ mr %r0,%r0
+ jnm 13f
+ ahi %r0,1000
+13: alr %r0,%r2
+ srdl %r0,12
+ al %r0,__VDSO_XTIME_NSEC(%r5) /* + xtime */
+ al %r1,__VDSO_XTIME_NSEC+4(%r5)
+ brc 12,14f
+ ahi %r0,1
+14: l %r2,__VDSO_XTIME_SEC+4(%r5)
+ cl %r4,__VDSO_UPD_COUNT+4(%r5) /* check update counter */
+ jne 11b
+ basr %r5,0
+15: ltr %r0,%r0
+ jnz 16f
+ cl %r1,20f-15b(%r5)
+ jl 17f
+16: ahi %r2,1
+ sl %r1,20f-15b(%r5)
+ brc 3,15b
+ ahi %r0,-1
+ j 15b
+17: st %r2,0(%r3) /* store tp->tv_sec */
+ st %r1,4(%r3) /* store tp->tv_nsec */
+18: lhi %r2,0
+ br %r14
+
+ /* Fallback to system call */
+19: lhi %r1,__NR_clock_gettime
+ svc 0
+ br %r14
+
+20: .long 1000000000
+21: .long _vdso_data - 0b
+ .cfi_endproc
+ .size __kernel_clock_gettime,.-__kernel_clock_gettime
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