arch/s390/kernel/vdso32/clock_gettime.S

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Userland implementation of clock_gettime() 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_clock_gettime
  16         .type  __kernel_clock_gettime,@function
  17 __kernel_clock_gettime:
  18         .cfi_startproc
  19         ahi     %r15,-16
  20         basr    %r5,0
  21 0:      al      %r5,21f-0b(%r5)                 /* get &_vdso_data */
  22         chi     %r2,__CLOCK_REALTIME_COARSE
  23         je      10f
  24         chi     %r2,__CLOCK_REALTIME
  25         je      11f
  26         chi     %r2,__CLOCK_MONOTONIC_COARSE
  27         je      9f
  28         chi     %r2,__CLOCK_MONOTONIC
  29         jne     19f
  30
  31         /* CLOCK_MONOTONIC */
  32 1:      l       %r4,__VDSO_UPD_COUNT+4(%r5)     /* load update counter */
  33         tml     %r4,0x0001                      /* pending update ? loop */
  34         jnz     1b
  35         stcke   0(%r15)                         /* Store TOD clock */
  36         lm      %r0,%r1,1(%r15)
  37         s       %r0,__VDSO_XTIME_STAMP(%r5)     /* TOD - cycle_last */
  38         sl      %r1,__VDSO_XTIME_STAMP+4(%r5)
  39         brc     3,2f
  40         ahi     %r0,-1
  41 2:      ms      %r0,__VDSO_TK_MULT(%r5)         /*  * tk->mult */
  42         lr      %r2,%r0
  43         l       %r0,__VDSO_TK_MULT(%r5)
  44         ltr     %r1,%r1
  45         mr      %r0,%r0
  46         jnm     3f
  47         a       %r0,__VDSO_TK_MULT(%r5)
  48 3:      alr     %r0,%r2
  49         al      %r0,__VDSO_WTOM_NSEC(%r5)
  50         al      %r1,__VDSO_WTOM_NSEC+4(%r5)
  51         brc     12,5f
  52         ahi     %r0,1
  53 5:      l       %r2,__VDSO_TK_SHIFT(%r5)        /* Timekeeper shift */
  54         srdl    %r0,0(%r2)                      /*  >> tk->shift */
  55         l       %r2,__VDSO_WTOM_SEC+4(%r5)
  56         cl      %r4,__VDSO_UPD_COUNT+4(%r5)     /* check update counter */
  57         jne     1b
  58         basr    %r5,0
  59 6:      ltr     %r0,%r0
  60         jnz     7f
  61         cl      %r1,20f-6b(%r5)
  62         jl      8f
  63 7:      ahi     %r2,1
  64         sl      %r1,20f-6b(%r5)
  65         brc     3,6b
  66         ahi     %r0,-1
  67         j       6b
  68 8:      st      %r2,0(%r3)                      /* store tp->tv_sec */
  69         st      %r1,4(%r3)                      /* store tp->tv_nsec */
  70         lhi     %r2,0
  71         ahi     %r15,16
  72         br      %r14
  73
  74         /* CLOCK_MONOTONIC_COARSE */
  75 9:      l       %r4,__VDSO_UPD_COUNT+4(%r5)     /* load update counter */
  76         tml     %r4,0x0001                      /* pending update ? loop */
  77         jnz     9b
  78         l       %r2,__VDSO_WTOM_CRS_SEC+4(%r5)
  79         l       %r1,__VDSO_WTOM_CRS_NSEC+4(%r5)
  80         cl      %r4,__VDSO_UPD_COUNT+4(%r5)     /* check update counter */
  81         jne     9b
  82         j       8b
  83
  84         /* CLOCK_REALTIME_COARSE */
  85 10:     l       %r4,__VDSO_UPD_COUNT+4(%r5)     /* load update counter */
  86         tml     %r4,0x0001                      /* pending update ? loop */
  87         jnz     10b
  88         l       %r2,__VDSO_XTIME_CRS_SEC+4(%r5)
  89         l       %r1,__VDSO_XTIME_CRS_NSEC+4(%r5)
  90         cl      %r4,__VDSO_UPD_COUNT+4(%r5)     /* check update counter */
  91         jne     10b
  92         j       17f
  93
  94         /* CLOCK_REALTIME */
  95 11:     l       %r4,__VDSO_UPD_COUNT+4(%r5)     /* load update counter */
  96         tml     %r4,0x0001                      /* pending update ? loop */
  97         jnz     11b
  98         stcke   0(%r15)                         /* Store TOD clock */
  99         lm      %r0,%r1,__VDSO_TS_END(%r5)      /* TOD steering end time */
 100         s       %r0,1(%r15)                     /* no - ts_steering_end */
 101         sl      %r1,5(%r15)
 102         brc     3,22f
 103         ahi     %r0,-1
 104 22:     ltr     %r0,%r0                         /* past end of steering? */
 105         jm      24f
 106         srdl    %r0,15                          /* 1 per 2^16 */
 107         tm      __VDSO_TS_DIR+3(%r5),0x01       /* steering direction? */
 108         jz      23f
 109         lcr     %r0,%r0                         /* negative TOD offset */
 110         lcr     %r1,%r1
 111         je      23f
 112         ahi     %r0,-1
 113 23:     a       %r0,1(%r15)                     /* add TOD timestamp */
 114         al      %r1,5(%r15)
 115         brc     12,25f
 116         ahi     %r0,1
 117         j       25f
 118 24:     lm      %r0,%r1,1(%r15)                 /* load TOD timestamp */
 119 25:     s       %r0,__VDSO_XTIME_STAMP(%r5)     /* TOD - cycle_last */
 120         sl      %r1,__VDSO_XTIME_STAMP+4(%r5)
 121         brc     3,12f
 122         ahi     %r0,-1
 123 12:     ms      %r0,__VDSO_TK_MULT(%r5)         /*  * tk->mult */
 124         lr      %r2,%r0
 125         l       %r0,__VDSO_TK_MULT(%r5)
 126         ltr     %r1,%r1
 127         mr      %r0,%r0
 128         jnm     13f
 129         a       %r0,__VDSO_TK_MULT(%r5)
 130 13:     alr     %r0,%r2
 131         al      %r0,__VDSO_XTIME_NSEC(%r5)      /*  + tk->xtime_nsec */
 132         al      %r1,__VDSO_XTIME_NSEC+4(%r5)
 133         brc     12,14f
 134         ahi     %r0,1
 135 14:     l       %r2,__VDSO_TK_SHIFT(%r5)        /* Timekeeper shift */
 136         srdl    %r0,0(%r2)                      /*  >> tk->shift */
 137         l       %r2,__VDSO_XTIME_SEC+4(%r5)
 138         cl      %r4,__VDSO_UPD_COUNT+4(%r5)     /* check update counter */
 139         jne     11b
 140         basr    %r5,0
 141 15:     ltr     %r0,%r0
 142         jnz     16f
 143         cl      %r1,20f-15b(%r5)
 144         jl      17f
 145 16:     ahi     %r2,1
 146         sl      %r1,20f-15b(%r5)
 147         brc     3,15b
 148         ahi     %r0,-1
 149         j       15b
 150 17:     st      %r2,0(%r3)                      /* store tp->tv_sec */
 151         st      %r1,4(%r3)                      /* store tp->tv_nsec */
 152         lhi     %r2,0
 153         ahi     %r15,16
 154         br      %r14
 155
 156         /* Fallback to system call */
 157 19:     lhi     %r1,__NR_clock_gettime
 158         svc     0
 159         ahi     %r15,16
 160         br      %r14
 161
 162 20:     .long   1000000000
 163 21:     .long   _vdso_data - 0b
 164         .cfi_endproc
 165         .size   __kernel_clock_gettime,.-__kernel_clock_gettime