linux/arch/s390/kernel/vdso64/gettimeofday.S

/*
 * 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 */
	msgf	%r1,__VDSO_NTP_MULT(%r5)	/*  * NTP adjustment */
	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
[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> 2008-12-25 13:38:36 +01:00			`/*`
			`* 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 */`
[S390] vdso: use ntp adjusted clock multiplier Commit "timekeeping: Fix clock_gettime vsyscall time warp" (0696b711e) introduced the new parameter "mult" to update_vsyscall(). This parameter contains the internal NTP adjusted clock multiplier. The s390x vdso did not use this adjusted multiplier. Instead, it used the constant clock multiplier for gettimeofday() and clock_gettime() variants. This may result in observable time warps as explained in commit 0696b711e. Make the NTP adjusted clock multiplier available to the s390x vdso implementation and use it for time calculations. Cc: <stable@kernel.org> Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> 2010-04-22 17:17:06 +02:00			`msgf %r1,__VDSO_NTP_MULT(%r5) /* * NTP adjustment */`
[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> 2008-12-25 13:38:36 +01:00			`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`