arch/csky/kernel/atomic.S

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 // Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
   3
   4 #include <linux/linkage.h>
   5 #include <abi/entry.h>
   6
   7 .text
   8
   9 /*
  10  * int csky_cmpxchg(int oldval, int newval, int *ptr)
  11  *
  12  * If *ptr != oldval && return 1,
  13  * else *ptr = newval return 0.
  14  */
  15 #ifdef CONFIG_CPU_HAS_LDSTEX
  16 ENTRY(csky_cmpxchg)
  17         USPTOKSP
  18         mfcr    a3, epc
  19         INCTRAP a3
  20
  21         subi    sp, 8
  22         stw     a3, (sp, 0)
  23         mfcr    a3, epsr
  24         stw     a3, (sp, 4)
  25
  26         psrset  ee
  27 1:
  28         ldex    a3, (a2)
  29         cmpne   a0, a3
  30         bt16    2f
  31         mov     a3, a1
  32         stex    a3, (a2)
  33         bez     a3, 1b
  34 2:
  35         sync.is
  36         mvc     a0
  37         ldw     a3, (sp, 0)
  38         mtcr    a3, epc
  39         ldw     a3, (sp, 4)
  40         mtcr    a3, epsr
  41         addi    sp, 8
  42         KSPTOUSP
  43         rte
  44 END(csky_cmpxchg)
  45 #else
  46 ENTRY(csky_cmpxchg)
  47         USPTOKSP
  48         mfcr    a3, epc
  49         INCTRAP a3
  50
  51         subi    sp, 8
  52         stw     a3, (sp, 0)
  53         mfcr    a3, epsr
  54         stw     a3, (sp, 4)
  55
  56         psrset  ee
  57 1:
  58         ldw     a3, (a2)
  59         cmpne   a0, a3
  60         bt16    3f
  61 2:
  62         stw     a1, (a2)
  63 3:
  64         mvc     a0
  65         ldw     a3, (sp, 0)
  66         mtcr    a3, epc
  67         ldw     a3, (sp, 4)
  68         mtcr    a3, epsr
  69         addi    sp, 8
  70         KSPTOUSP
  71         rte
  72 END(csky_cmpxchg)
  73
  74 /*
  75  * Called from tlbmodified exception
  76  */
  77 ENTRY(csky_cmpxchg_fixup)
  78         mfcr    a0, epc
  79         lrw     a1, 2b
  80         cmpne   a1, a0
  81         bt      1f
  82         subi    a1, (2b - 1b)
  83         stw     a1, (sp, LSAVE_PC)
  84 1:
  85         rts
  86 END(csky_cmpxchg_fixup)
  87 #endif