forked from luck/tmp_suning_uos_patched
070b7be633
If gettimeofday / clock_gettime are called multiple times in a row the STCK instruction will stall until a difference in the result is visible. This unnecessarily slows down the vdso calls, use stcke instead of stck to get rid of the stall. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
124 lines
3.1 KiB
ArmAsm
124 lines
3.1 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 5f
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cghi %r2,__CLOCK_THREAD_CPUTIME_ID
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je 9f
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cghi %r2,-2 /* Per-thread CPUCLOCK with PID=0, VIRT=1 */
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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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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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stcke 48(%r15) /* Store TOD clock */
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lgf %r2,__VDSO_TK_SHIFT(%r5) /* Timekeeper shift */
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lg %r0,__VDSO_WTOM_SEC(%r5)
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lg %r1,49(%r15)
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sg %r1,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */
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msgf %r1,__VDSO_TK_MULT(%r5) /* * tk->mult */
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alg %r1,__VDSO_WTOM_NSEC(%r5)
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srlg %r1,%r1,0(%r2) /* >> tk->shift */
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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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lghi %r2,0
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br %r14
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/* CLOCK_REALTIME */
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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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stcke 48(%r15) /* Store TOD clock */
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lgf %r2,__VDSO_TK_SHIFT(%r5) /* Timekeeper shift */
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lg %r1,49(%r15)
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sg %r1,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */
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msgf %r1,__VDSO_TK_MULT(%r5) /* * tk->mult */
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alg %r1,__VDSO_XTIME_NSEC(%r5) /* + tk->xtime_nsec */
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srlg %r1,%r1,0(%r2) /* >> tk->shift */
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lg %r0,__VDSO_XTIME_SEC(%r5) /* tk->xtime_sec */
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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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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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