root/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 ENTRY(csky_cmpxchg)
  16         USPTOKSP
  17         mfcr    a3, epc
  18         addi    a3, TRAP0_SIZE
  19 
  20         subi    sp, 16
  21         stw     a3, (sp, 0)
  22         mfcr    a3, epsr
  23         stw     a3, (sp, 4)
  24         mfcr    a3, usp
  25         stw     a3, (sp, 8)
  26 
  27         psrset  ee
  28 #ifdef CONFIG_CPU_HAS_LDSTEX
  29 1:
  30         ldex    a3, (a2)
  31         cmpne   a0, a3
  32         bt16    2f
  33         mov     a3, a1
  34         stex    a3, (a2)
  35         bez     a3, 1b
  36 2:
  37         sync.is
  38 #else
  39 1:
  40         ldw     a3, (a2)
  41         cmpne   a0, a3
  42         bt16    3f
  43 2:
  44         stw     a1, (a2)
  45 3:
  46 #endif
  47         mvc     a0
  48         ldw     a3, (sp, 0)
  49         mtcr    a3, epc
  50         ldw     a3, (sp, 4)
  51         mtcr    a3, epsr
  52         ldw     a3, (sp, 8)
  53         mtcr    a3, usp
  54         addi    sp, 16
  55         KSPTOUSP
  56         rte
  57 END(csky_cmpxchg)
  58 
  59 #ifndef CONFIG_CPU_HAS_LDSTEX
  60 /*
  61  * Called from tlbmodified exception
  62  */
  63 ENTRY(csky_cmpxchg_fixup)
  64         mfcr    a0, epc
  65         lrw     a1, 2b
  66         cmpne   a1, a0
  67         bt      1f
  68         subi    a1, (2b - 1b)
  69         stw     a1, (sp, LSAVE_PC)
  70 1:
  71         rts
  72 END(csky_cmpxchg_fixup)
  73 #endif