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| author |   Martin Schwidefsky <schwidefsky@de.ibm.com> | 2008-12-25 13:38:36 +0100 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2008-12-25 13:38:55 +0100 |
| commit | b020632e40c3ed5e8c0c066d022672907e8401cf (patch) | |
| tree | d7f805bd27e8378436fbba7e7457afbd10c22ed8 /arch/s390/kernel/vdso64/clock_getres.S | |
| parent | [S390] arch_setup_additional_pages arguments (diff) | |
| download | linux-dev-b020632e40c3ed5e8c0c066d022672907e8401cf.tar.xz linux-dev-b020632e40c3ed5e8c0c066d022672907e8401cf.zip | |
[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/vdso64/clock_getres.S')
| -rw-r--r-- | arch/s390/kernel/vdso64/clock_getres.S | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/arch/s390/kernel/vdso64/clock_getres.S b/arch/s390/kernel/vdso64/clock_getres.S new file mode 100644 index 000000000000..488e31a3c0e7 --- /dev/null +++ b/arch/s390/kernel/vdso64/clock_getres.S @@ -0,0 +1,39 @@ +/* + * Userland implementation of clock_getres() for 64 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_getres + .type __kernel_clock_getres,@function +__kernel_clock_getres: + .cfi_startproc + cghi %r2,CLOCK_REALTIME + je 0f + cghi %r2,CLOCK_MONOTONIC + jne 2f +0: ltgr %r3,%r3 + jz 1f /* res == NULL */ + larl %r1,3f + lg %r0,0(%r1) + xc 0(8,%r3),0(%r3) /* set tp->tv_sec to zero */ + stg %r0,8(%r3) /* store tp->tv_usec */ +1: lghi %r2,0 + br %r14 +2: lghi %r1,__NR_clock_getres /* fallback to svc */ + svc 0 + br %r14 +3: .quad CLOCK_REALTIME_RES + .cfi_endproc + .size __kernel_clock_getres,.-__kernel_clock_getres |