diff options
| 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/gettimeofday.S | |
| parent | fc5243d98ac2575ad14a974b3c097e9ba874c03d (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/vdso64/gettimeofday.S')
| -rw-r--r-- | arch/s390/kernel/vdso64/gettimeofday.S | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/arch/s390/kernel/vdso64/gettimeofday.S b/arch/s390/kernel/vdso64/gettimeofday.S new file mode 100644 index 00000000000..f873e75634e --- /dev/null +++ b/arch/s390/kernel/vdso64/gettimeofday.S @@ -0,0 +1,56 @@ +/* + * Userland implementation of gettimeofday() 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_gettimeofday + .type __kernel_gettimeofday,@function +__kernel_gettimeofday: + .cfi_startproc + larl %r5,_vdso_data +0: ltgr %r3,%r3 /* check if tz is NULL */ + je 1f + mvc 0(8,%r3),__VDSO_TIMEZONE(%r5) +1: ltgr %r2,%r2 /* check if tv is NULL */ + je 4f + lg %r4,__VDSO_UPD_COUNT(%r5) /* load update counter */ + tmll %r4,0x0001 /* pending update ? loop */ + jnz 0b + stck 48(%r15) /* Store TOD clock */ + lg %r1,48(%r15) + sg %r1,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */ + mghi %r1,1000 + srlg %r1,%r1,12 /* cyc2ns(clock,cycle_delta) */ + alg %r1,__VDSO_XTIME_NSEC(%r5) /* + xtime.tv_nsec */ + lg %r0,__VDSO_XTIME_SEC(%r5) /* xtime.tv_sec */ + clg %r4,__VDSO_UPD_COUNT(%r5) /* check update counter */ + jne 0b + larl %r5,5f +2: clg %r1,0(%r5) + jl 3f + slg %r1,0(%r5) + aghi %r0,1 + j 2b +3: stg %r0,0(%r2) /* store tv->tv_sec */ + slgr %r0,%r0 /* tv_nsec -> tv_usec */ + ml %r0,8(%r5) + srlg %r0,%r0,6 + stg %r0,8(%r2) /* store tv->tv_usec */ +4: lghi %r2,0 + br %r14 +5: .quad 1000000000 + .long 274877907 + .cfi_endproc + .size __kernel_gettimeofday,.-__kernel_gettimeofday |