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>
126 lines
3.2 KiB
ArmAsm
126 lines
3.2 KiB
ArmAsm
/*
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* Userland implementation of clock_gettime() 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_clock_gettime
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.type __kernel_clock_gettime,@function
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__kernel_clock_gettime:
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.cfi_startproc
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larl %r5,_vdso_data
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cghi %r2,CLOCK_REALTIME
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je 4f
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cghi %r2,-2 /* CLOCK_THREAD_CPUTIME_ID for this thread */
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je 9f
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cghi %r2,CLOCK_MONOTONIC
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jne 12f
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/* CLOCK_MONOTONIC */
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ltgr %r3,%r3
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jz 3f /* tp == NULL */
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0: 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 */
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lg %r0,__VDSO_XTIME_SEC(%r5)
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alg %r1,__VDSO_WTOM_NSEC(%r5) /* + wall_to_monotonic */
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alg %r0,__VDSO_WTOM_SEC(%r5)
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clg %r4,__VDSO_UPD_COUNT(%r5) /* check update counter */
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jne 0b
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larl %r5,13f
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1: clg %r1,0(%r5)
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jl 2f
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slg %r1,0(%r5)
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aghi %r0,1
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j 1b
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2: stg %r0,0(%r3) /* store tp->tv_sec */
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stg %r1,8(%r3) /* store tp->tv_nsec */
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3: lghi %r2,0
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br %r14
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/* CLOCK_REALTIME */
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4: ltr %r3,%r3 /* tp == NULL */
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jz 8f
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5: lg %r4,__VDSO_UPD_COUNT(%r5) /* load update counter */
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tmll %r4,0x0001 /* pending update ? loop */
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jnz 5b
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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 */
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lg %r0,__VDSO_XTIME_SEC(%r5)
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clg %r4,__VDSO_UPD_COUNT(%r5) /* check update counter */
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jne 5b
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larl %r5,13f
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6: clg %r1,0(%r5)
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jl 7f
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slg %r1,0(%r5)
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aghi %r0,1
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j 6b
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7: stg %r0,0(%r3) /* store tp->tv_sec */
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stg %r1,8(%r3) /* store tp->tv_nsec */
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8: lghi %r2,0
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br %r14
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/* CLOCK_THREAD_CPUTIME_ID for this thread */
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9: icm %r0,15,__VDSO_ECTG_OK(%r5)
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jz 12f
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ear %r2,%a4
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llilh %r4,0x0100
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sar %a4,%r4
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lghi %r4,0
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epsw %r5,0
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sacf 512 /* Magic ectg instruction */
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.insn ssf,0xc80100000000,__VDSO_ECTG_BASE(4),__VDSO_ECTG_USER(4),4
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tml %r5,0x4000
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jo 11f
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tml %r5,0x8000
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jno 10f
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sacf 256
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j 11f
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10: sacf 0
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11: sar %a4,%r2
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algr %r1,%r0 /* r1 = cputime as TOD value */
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mghi %r1,1000 /* convert to nanoseconds */
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srlg %r1,%r1,12 /* r1 = cputime in nanosec */
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lgr %r4,%r1
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larl %r5,13f
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srlg %r1,%r1,9 /* divide by 1000000000 */
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mlg %r0,8(%r5)
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srlg %r0,%r0,11 /* r0 = tv_sec */
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stg %r0,0(%r3)
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msg %r0,0(%r5) /* calculate tv_nsec */
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slgr %r4,%r0 /* r4 = tv_nsec */
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stg %r4,8(%r3)
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lghi %r2,0
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br %r14
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/* Fallback to system call */
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12: lghi %r1,__NR_clock_gettime
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svc 0
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br %r14
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13: .quad 1000000000
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14: .quad 19342813113834067
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.cfi_endproc
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.size __kernel_clock_gettime,.-__kernel_clock_gettime
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