arch/s390/kernel/vdso32/gettimeofday.S

   1 /*
   2  * Userland implementation of gettimeofday() for 32 bits processes in a
   3  * s390 kernel for use in the vDSO
   4  *
   5  *  Copyright IBM Corp. 2008
   6  *  Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License (version 2 only)
  10  * as published by the Free Software Foundation.
  11  */
  12 #include <asm/vdso.h>
  13 #include <asm/asm-offsets.h>
  14 #include <asm/unistd.h>
  15
  16         .text
  17         .align 4
  18         .globl __kernel_gettimeofday
  19         .type  __kernel_gettimeofday,@function
  20 __kernel_gettimeofday:
  21         .cfi_startproc
  22         ahi     %r15,-16
  23         basr    %r5,0
  24 0:      al      %r5,13f-0b(%r5)                 /* get &_vdso_data */
  25 1:      ltr     %r3,%r3                         /* check if tz is NULL */
  26         je      2f
  27         mvc     0(8,%r3),__VDSO_TIMEZONE(%r5)
  28 2:      ltr     %r2,%r2                         /* check if tv is NULL */
  29         je      10f
  30         l       %r4,__VDSO_UPD_COUNT+4(%r5)     /* load update counter */
  31         tml     %r4,0x0001                      /* pending update ? loop */
  32         jnz     1b
  33         stcke   0(%r15)                         /* Store TOD clock */
  34         lm      %r0,%r1,__VDSO_TS_END(%r5)      /* TOD steering end time */
  35         s       %r0,1(%r15)
  36         sl      %r1,5(%r15)
  37         brc     3,14f
  38         ahi     %r0,-1
  39 14:     ltr     %r0,%r0                         /* past end of steering? */
  40         jm      16f
  41         srdl    %r0,15                          /* 1 per 2^16 */
  42         tm      __VDSO_TS_DIR+3(%r5),0x01       /* steering direction? */
  43         jz      15f
  44         lcr     %r0,%r0                         /* negative TOD offset */
  45         lcr     %r1,%r1
  46         je      15f
  47         ahi     %r0,-1
  48 15:     a       %r0,1(%r15)                     /* add TOD timestamp */
  49         al      %r1,5(%r15)
  50         brc     12,17f
  51         ahi     %r0,1
  52         j       17f
  53 16:     lm      %r0,%r1,1(%r15)                 /* load TOD timestamp */
  54 17:     s       %r0,__VDSO_XTIME_STAMP(%r5)     /* TOD - cycle_last */
  55         sl      %r1,__VDSO_XTIME_STAMP+4(%r5)
  56         brc     3,3f
  57         ahi     %r0,-1
  58 3:      ms      %r0,__VDSO_TK_MULT(%r5)         /*  * tk->mult */
  59         st      %r0,0(%r15)
  60         l       %r0,__VDSO_TK_MULT(%r5)
  61         ltr     %r1,%r1
  62         mr      %r0,%r0
  63         jnm     4f
  64         a       %r0,__VDSO_TK_MULT(%r5)
  65 4:      al      %r0,0(%r15)
  66         al      %r0,__VDSO_XTIME_NSEC(%r5)      /*  + xtime */
  67         al      %r1,__VDSO_XTIME_NSEC+4(%r5)
  68         brc     12,5f
  69         ahi     %r0,1
  70 5:      mvc     0(4,%r15),__VDSO_XTIME_SEC+4(%r5)
  71         cl      %r4,__VDSO_UPD_COUNT+4(%r5)     /* check update counter */
  72         jne     1b
  73         l       %r4,__VDSO_TK_SHIFT(%r5)        /* Timekeeper shift */
  74         srdl    %r0,0(%r4)                      /*  >> tk->shift */
  75         l       %r4,0(%r15)                     /* get tv_sec from stack */
  76         basr    %r5,0
  77 6:      ltr     %r0,%r0
  78         jnz     7f
  79         cl      %r1,11f-6b(%r5)
  80         jl      8f
  81 7:      ahi     %r4,1
  82         sl      %r1,11f-6b(%r5)
  83         brc     3,6b
  84         ahi     %r0,-1
  85         j       6b
  86 8:      st      %r4,0(%r2)                      /* store tv->tv_sec */
  87         ltr     %r1,%r1
  88         m       %r0,12f-6b(%r5)
  89         jnm     9f
  90         al      %r0,12f-6b(%r5)
  91 9:      srl     %r0,6
  92         st      %r0,4(%r2)                      /* store tv->tv_usec */
  93 10:     slr     %r2,%r2
  94         ahi     %r15,16
  95         br      %r14
  96 11:     .long   1000000000
  97 12:     .long   274877907
  98 13:     .long   _vdso_data - 0b
  99         .cfi_endproc
 100         .size   __kernel_gettimeofday,.-__kernel_gettimeofday