arch/s390/kernel/vdso32/gettimeofday.S

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Userland implementation of gettimeofday() for 32 bits processes in a
   4  * s390 kernel for use in the vDSO
   5  *
   6  *  Copyright IBM Corp. 2008
   7  *  Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
   8  */
   9 #include <asm/vdso.h>
  10 #include <asm/asm-offsets.h>
  11 #include <asm/unistd.h>
  12
  13         .text
  14         .align 4
  15         .globl __kernel_gettimeofday
  16         .type  __kernel_gettimeofday,@function
  17 __kernel_gettimeofday:
  18         .cfi_startproc
  19         ahi     %r15,-16
  20         basr    %r5,0
  21 0:      al      %r5,13f-0b(%r5)                 /* get &_vdso_data */
  22 1:      ltr     %r3,%r3                         /* check if tz is NULL */
  23         je      2f
  24         mvc     0(8,%r3),__VDSO_TIMEZONE(%r5)
  25 2:      ltr     %r2,%r2                         /* check if tv is NULL */
  26         je      10f
  27         l       %r4,__VDSO_UPD_COUNT+4(%r5)     /* load update counter */
  28         tml     %r4,0x0001                      /* pending update ? loop */
  29         jnz     1b
  30         stcke   0(%r15)                         /* Store TOD clock */
  31         lm      %r0,%r1,__VDSO_TS_END(%r5)      /* TOD steering end time */
  32         s       %r0,1(%r15)
  33         sl      %r1,5(%r15)
  34         brc     3,14f
  35         ahi     %r0,-1
  36 14:     ltr     %r0,%r0                         /* past end of steering? */
  37         jm      16f
  38         srdl    %r0,15                          /* 1 per 2^16 */
  39         tm      __VDSO_TS_DIR+3(%r5),0x01       /* steering direction? */
  40         jz      15f
  41         lcr     %r0,%r0                         /* negative TOD offset */
  42         lcr     %r1,%r1
  43         je      15f
  44         ahi     %r0,-1
  45 15:     a       %r0,1(%r15)                     /* add TOD timestamp */
  46         al      %r1,5(%r15)
  47         brc     12,17f
  48         ahi     %r0,1
  49         j       17f
  50 16:     lm      %r0,%r1,1(%r15)                 /* load TOD timestamp */
  51 17:     s       %r0,__VDSO_XTIME_STAMP(%r5)     /* TOD - cycle_last */
  52         sl      %r1,__VDSO_XTIME_STAMP+4(%r5)
  53         brc     3,3f
  54         ahi     %r0,-1
  55 3:      ms      %r0,__VDSO_TK_MULT(%r5)         /*  * tk->mult */
  56         st      %r0,0(%r15)
  57         l       %r0,__VDSO_TK_MULT(%r5)
  58         ltr     %r1,%r1
  59         mr      %r0,%r0
  60         jnm     4f
  61         a       %r0,__VDSO_TK_MULT(%r5)
  62 4:      al      %r0,0(%r15)
  63         al      %r0,__VDSO_XTIME_NSEC(%r5)      /*  + xtime */
  64         al      %r1,__VDSO_XTIME_NSEC+4(%r5)
  65         brc     12,5f
  66         ahi     %r0,1
  67 5:      mvc     0(4,%r15),__VDSO_XTIME_SEC+4(%r5)
  68         cl      %r4,__VDSO_UPD_COUNT+4(%r5)     /* check update counter */
  69         jne     1b
  70         l       %r4,__VDSO_TK_SHIFT(%r5)        /* Timekeeper shift */
  71         srdl    %r0,0(%r4)                      /*  >> tk->shift */
  72         l       %r4,0(%r15)                     /* get tv_sec from stack */
  73         basr    %r5,0
  74 6:      ltr     %r0,%r0
  75         jnz     7f
  76         cl      %r1,11f-6b(%r5)
  77         jl      8f
  78 7:      ahi     %r4,1
  79         sl      %r1,11f-6b(%r5)
  80         brc     3,6b
  81         ahi     %r0,-1
  82         j       6b
  83 8:      st      %r4,0(%r2)                      /* store tv->tv_sec */
  84         ltr     %r1,%r1
  85         m       %r0,12f-6b(%r5)
  86         jnm     9f
  87         al      %r0,12f-6b(%r5)
  88 9:      srl     %r0,6
  89         st      %r0,4(%r2)                      /* store tv->tv_usec */
  90 10:     slr     %r2,%r2
  91         ahi     %r15,16
  92         br      %r14
  93 11:     .long   1000000000
  94 12:     .long   274877907
  95 13:     .long   _vdso_data - 0b
  96         .cfi_endproc
  97         .size   __kernel_gettimeofday,.-__kernel_gettimeofday