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>
129 lines
3.0 KiB
ArmAsm
129 lines
3.0 KiB
ArmAsm
/*
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* Userland implementation of clock_gettime() for 32 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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basr %r5,0
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0: al %r5,21f-0b(%r5) /* get &_vdso_data */
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chi %r2,CLOCK_REALTIME
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je 10f
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chi %r2,CLOCK_MONOTONIC
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jne 19f
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/* CLOCK_MONOTONIC */
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ltr %r3,%r3
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jz 9f /* tp == NULL */
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1: l %r4,__VDSO_UPD_COUNT+4(%r5) /* load update counter */
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tml %r4,0x0001 /* pending update ? loop */
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jnz 1b
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stck 24(%r15) /* Store TOD clock */
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lm %r0,%r1,24(%r15)
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s %r0,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */
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sl %r1,__VDSO_XTIME_STAMP+4(%r5)
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brc 3,2f
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ahi %r0,-1
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2: ms %r0,__VDSO_NTP_MULT(%r5) /* cyc2ns(clock,cycle_delta) */
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lr %r2,%r0
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l %r0,__VDSO_NTP_MULT(%r5)
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ltr %r1,%r1
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mr %r0,%r0
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jnm 3f
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a %r0,__VDSO_NTP_MULT(%r5)
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3: alr %r0,%r2
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srdl %r0,12
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al %r0,__VDSO_XTIME_NSEC(%r5) /* + xtime */
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al %r1,__VDSO_XTIME_NSEC+4(%r5)
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brc 12,4f
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ahi %r0,1
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4: l %r2,__VDSO_XTIME_SEC+4(%r5)
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al %r0,__VDSO_WTOM_NSEC(%r5) /* + wall_to_monotonic */
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al %r1,__VDSO_WTOM_NSEC+4(%r5)
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brc 12,5f
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ahi %r0,1
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5: al %r2,__VDSO_WTOM_SEC+4(%r5)
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cl %r4,__VDSO_UPD_COUNT+4(%r5) /* check update counter */
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jne 1b
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basr %r5,0
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6: ltr %r0,%r0
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jnz 7f
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cl %r1,20f-6b(%r5)
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jl 8f
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7: ahi %r2,1
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sl %r1,20f-6b(%r5)
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brc 3,6b
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ahi %r0,-1
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j 6b
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8: st %r2,0(%r3) /* store tp->tv_sec */
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st %r1,4(%r3) /* store tp->tv_nsec */
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9: lhi %r2,0
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br %r14
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/* CLOCK_REALTIME */
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10: ltr %r3,%r3 /* tp == NULL */
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jz 18f
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11: l %r4,__VDSO_UPD_COUNT+4(%r5) /* load update counter */
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tml %r4,0x0001 /* pending update ? loop */
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jnz 11b
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stck 24(%r15) /* Store TOD clock */
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lm %r0,%r1,24(%r15)
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s %r0,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */
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sl %r1,__VDSO_XTIME_STAMP+4(%r5)
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brc 3,12f
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ahi %r0,-1
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12: ms %r0,__VDSO_NTP_MULT(%r5) /* cyc2ns(clock,cycle_delta) */
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lr %r2,%r0
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l %r0,__VDSO_NTP_MULT(%r5)
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ltr %r1,%r1
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mr %r0,%r0
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jnm 13f
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a %r0,__VDSO_NTP_MULT(%r5)
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13: alr %r0,%r2
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srdl %r0,12
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al %r0,__VDSO_XTIME_NSEC(%r5) /* + xtime */
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al %r1,__VDSO_XTIME_NSEC+4(%r5)
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brc 12,14f
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ahi %r0,1
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14: l %r2,__VDSO_XTIME_SEC+4(%r5)
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cl %r4,__VDSO_UPD_COUNT+4(%r5) /* check update counter */
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jne 11b
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basr %r5,0
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15: ltr %r0,%r0
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jnz 16f
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cl %r1,20f-15b(%r5)
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jl 17f
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16: ahi %r2,1
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sl %r1,20f-15b(%r5)
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brc 3,15b
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ahi %r0,-1
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j 15b
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17: st %r2,0(%r3) /* store tp->tv_sec */
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st %r1,4(%r3) /* store tp->tv_nsec */
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18: lhi %r2,0
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br %r14
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/* Fallback to system call */
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19: lhi %r1,__NR_clock_gettime
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svc 0
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br %r14
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20: .long 1000000000
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21: .long _vdso_data - 0b
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.cfi_endproc
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.size __kernel_clock_gettime,.-__kernel_clock_gettime
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