arch/s390/kernel/vdso64/clock_getres.S

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Userland implementation of clock_getres() for 64 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_getres
  16         .type  __kernel_clock_getres,@function
  17 __kernel_clock_getres:
  18         .cfi_startproc
  19         larl    %r1,4f
  20         cghi    %r2,__CLOCK_REALTIME_COARSE
  21         je      0f
  22         cghi    %r2,__CLOCK_MONOTONIC_COARSE
  23         je      0f
  24         larl    %r1,3f
  25         cghi    %r2,__CLOCK_REALTIME
  26         je      0f
  27         cghi    %r2,__CLOCK_MONOTONIC
  28         je      0f
  29         cghi    %r2,__CLOCK_THREAD_CPUTIME_ID
  30         je      0f
  31         cghi    %r2,-2          /* Per-thread CPUCLOCK with PID=0, VIRT=1 */
  32         jne     2f
  33         larl    %r5,_vdso_data
  34         icm     %r0,15,__LC_ECTG_OK(%r5)
  35         jz      2f
  36 0:      ltgr    %r3,%r3
  37         jz      1f                              /* res == NULL */
  38         lg      %r0,0(%r1)
  39         xc      0(8,%r3),0(%r3)                 /* set tp->tv_sec to zero */
  40         stg     %r0,8(%r3)                      /* store tp->tv_usec */
  41 1:      lghi    %r2,0
  42         br      %r14
  43 2:      lghi    %r1,__NR_clock_getres           /* fallback to svc */
  44         svc     0
  45         br      %r14
  46 3:      .quad   __CLOCK_REALTIME_RES
  47 4:      .quad   __CLOCK_COARSE_RES
  48         .cfi_endproc
  49         .size   __kernel_clock_getres,.-__kernel_clock_getres