root/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 #include <asm/dwarf.h>
  13 #include <asm/ptrace.h>
  14 
  15         .text
  16         .align 4
  17         .globl __kernel_gettimeofday
  18         .type  __kernel_gettimeofday,@function
  19 __kernel_gettimeofday:
  20         CFI_STARTPROC
  21         ahi     %r15,-16
  22         CFI_ADJUST_CFA_OFFSET 16
  23         CFI_VAL_OFFSET 15, -STACK_FRAME_OVERHEAD
  24         basr    %r5,0
  25 0:      al      %r5,13f-0b(%r5)                 /* get &_vdso_data */
  26 1:      ltr     %r3,%r3                         /* check if tz is NULL */
  27         je      2f
  28         mvc     0(8,%r3),__VDSO_TIMEZONE(%r5)
  29 2:      ltr     %r2,%r2                         /* check if tv is NULL */
  30         je      10f
  31         l       %r4,__VDSO_UPD_COUNT+4(%r5)     /* load update counter */
  32         tml     %r4,0x0001                      /* pending update ? loop */
  33         jnz     1b
  34         stcke   0(%r15)                         /* Store TOD clock */
  35         lm      %r0,%r1,__VDSO_TS_END(%r5)      /* TOD steering end time */
  36         s       %r0,1(%r15)
  37         sl      %r1,5(%r15)
  38         brc     3,14f
  39         ahi     %r0,-1
  40 14:     ltr     %r0,%r0                         /* past end of steering? */
  41         jm      16f
  42         srdl    %r0,15                          /* 1 per 2^16 */
  43         tm      __VDSO_TS_DIR+3(%r5),0x01       /* steering direction? */
  44         jz      15f
  45         lcr     %r0,%r0                         /* negative TOD offset */
  46         lcr     %r1,%r1
  47         je      15f
  48         ahi     %r0,-1
  49 15:     a       %r0,1(%r15)                     /* add TOD timestamp */
  50         al      %r1,5(%r15)
  51         brc     12,17f
  52         ahi     %r0,1
  53         j       17f
  54 16:     lm      %r0,%r1,1(%r15)                 /* load TOD timestamp */
  55 17:     s       %r0,__VDSO_XTIME_STAMP(%r5)     /* TOD - cycle_last */
  56         sl      %r1,__VDSO_XTIME_STAMP+4(%r5)
  57         brc     3,3f
  58         ahi     %r0,-1
  59 3:      ms      %r0,__VDSO_TK_MULT(%r5)         /*  * tk->mult */
  60         st      %r0,0(%r15)
  61         l       %r0,__VDSO_TK_MULT(%r5)
  62         ltr     %r1,%r1
  63         mr      %r0,%r0
  64         jnm     4f
  65         a       %r0,__VDSO_TK_MULT(%r5)
  66 4:      al      %r0,0(%r15)
  67         al      %r0,__VDSO_XTIME_NSEC(%r5)      /*  + xtime */
  68         al      %r1,__VDSO_XTIME_NSEC+4(%r5)
  69         brc     12,5f
  70         ahi     %r0,1
  71 5:      mvc     0(4,%r15),__VDSO_XTIME_SEC+4(%r5)
  72         cl      %r4,__VDSO_UPD_COUNT+4(%r5)     /* check update counter */
  73         jne     1b
  74         l       %r4,__VDSO_TK_SHIFT(%r5)        /* Timekeeper shift */
  75         srdl    %r0,0(%r4)                      /*  >> tk->shift */
  76         l       %r4,0(%r15)                     /* get tv_sec from stack */
  77         basr    %r5,0
  78 6:      ltr     %r0,%r0
  79         jnz     7f
  80         cl      %r1,11f-6b(%r5)
  81         jl      8f
  82 7:      ahi     %r4,1
  83         sl      %r1,11f-6b(%r5)
  84         brc     3,6b
  85         ahi     %r0,-1
  86         j       6b
  87 8:      st      %r4,0(%r2)                      /* store tv->tv_sec */
  88         ltr     %r1,%r1
  89         m       %r0,12f-6b(%r5)
  90         jnm     9f
  91         al      %r0,12f-6b(%r5)
  92 9:      srl     %r0,6
  93         st      %r0,4(%r2)                      /* store tv->tv_usec */
  94 10:     slr     %r2,%r2
  95         ahi     %r15,16
  96         CFI_ADJUST_CFA_OFFSET -16
  97         CFI_RESTORE 15
  98         br      %r14
  99         CFI_ENDPROC
 100 11:     .long   1000000000
 101 12:     .long   274877907
 102 13:     .long   _vdso_data - 0b
 103         .size   __kernel_gettimeofday,.-__kernel_gettimeofday