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157a1a27d5
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>
57 lines
1.6 KiB
ArmAsm
57 lines
1.6 KiB
ArmAsm
/*
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* Userland implementation of gettimeofday() for 64 bits processes in a
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* s390 kernel for use in the vDSO
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*
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* Copyright IBM Corp. 2008
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* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License (version 2 only)
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* as published by the Free Software Foundation.
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*/
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#include <asm/vdso.h>
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#include <asm/asm-offsets.h>
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#include <asm/unistd.h>
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.text
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.align 4
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.globl __kernel_gettimeofday
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.type __kernel_gettimeofday,@function
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__kernel_gettimeofday:
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.cfi_startproc
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larl %r5,_vdso_data
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0: ltgr %r3,%r3 /* check if tz is NULL */
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je 1f
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mvc 0(8,%r3),__VDSO_TIMEZONE(%r5)
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1: ltgr %r2,%r2 /* check if tv is NULL */
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je 4f
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lg %r4,__VDSO_UPD_COUNT(%r5) /* load update counter */
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tmll %r4,0x0001 /* pending update ? loop */
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jnz 0b
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stck 48(%r15) /* Store TOD clock */
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lg %r1,48(%r15)
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sg %r1,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */
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msgf %r1,__VDSO_NTP_MULT(%r5) /* * NTP adjustment */
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srlg %r1,%r1,12 /* cyc2ns(clock,cycle_delta) */
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alg %r1,__VDSO_XTIME_NSEC(%r5) /* + xtime.tv_nsec */
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lg %r0,__VDSO_XTIME_SEC(%r5) /* xtime.tv_sec */
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clg %r4,__VDSO_UPD_COUNT(%r5) /* check update counter */
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jne 0b
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larl %r5,5f
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2: clg %r1,0(%r5)
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jl 3f
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slg %r1,0(%r5)
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aghi %r0,1
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j 2b
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3: stg %r0,0(%r2) /* store tv->tv_sec */
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slgr %r0,%r0 /* tv_nsec -> tv_usec */
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ml %r0,8(%r5)
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srlg %r0,%r0,6
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stg %r0,8(%r2) /* store tv->tv_usec */
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4: lghi %r2,0
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br %r14
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5: .quad 1000000000
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.long 274877907
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.cfi_endproc
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.size __kernel_gettimeofday,.-__kernel_gettimeofday
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