arch/arm/lib/bitops.h

   1 #include <asm/unwind.h>
   2
   3 #if __LINUX_ARM_ARCH__ >= 6
   4         .macro  bitop, name, instr
   5 ENTRY(  \name           )
   6 UNWIND( .fnstart        )
   7         ands    ip, r1, #3
   8         strneb  r1, [ip]                @ assert word-aligned
   9         mov     r2, #1
  10         and     r3, r0, #31             @ Get bit offset
  11         mov     r0, r0, lsr #5
  12         add     r1, r1, r0, lsl #2      @ Get word offset
  13 #if __LINUX_ARM_ARCH__ >= 7 && defined(CONFIG_SMP)
  14         .arch_extension mp
  15         ALT_SMP(W(pldw) [r1])
  16         ALT_UP(W(nop))
  17 #endif
  18         mov     r3, r2, lsl r3
  19 1:      ldrex   r2, [r1]
  20         \instr  r2, r2, r3
  21         strex   r0, r2, [r1]
  22         cmp     r0, #0
  23         bne     1b
  24         bx      lr
  25 UNWIND( .fnend          )
  26 ENDPROC(\name           )
  27         .endm
  28
  29         .macro  testop, name, instr, store
  30 ENTRY(  \name           )
  31 UNWIND( .fnstart        )
  32         ands    ip, r1, #3
  33         strneb  r1, [ip]                @ assert word-aligned
  34         mov     r2, #1
  35         and     r3, r0, #31             @ Get bit offset
  36         mov     r0, r0, lsr #5
  37         add     r1, r1, r0, lsl #2      @ Get word offset
  38         mov     r3, r2, lsl r3          @ create mask
  39         smp_dmb
  40 #if __LINUX_ARM_ARCH__ >= 7 && defined(CONFIG_SMP)
  41         .arch_extension mp
  42         ALT_SMP(W(pldw) [r1])
  43         ALT_UP(W(nop))
  44 #endif
  45 1:      ldrex   r2, [r1]
  46         ands    r0, r2, r3              @ save old value of bit
  47         \instr  r2, r2, r3              @ toggle bit
  48         strex   ip, r2, [r1]
  49         cmp     ip, #0
  50         bne     1b
  51         smp_dmb
  52         cmp     r0, #0
  53         movne   r0, #1
  54 2:      bx      lr
  55 UNWIND( .fnend          )
  56 ENDPROC(\name           )
  57         .endm
  58 #else
  59         .macro  bitop, name, instr
  60 ENTRY(  \name           )
  61 UNWIND( .fnstart        )
  62         ands    ip, r1, #3
  63         strneb  r1, [ip]                @ assert word-aligned
  64         and     r2, r0, #31
  65         mov     r0, r0, lsr #5
  66         mov     r3, #1
  67         mov     r3, r3, lsl r2
  68         save_and_disable_irqs ip
  69         ldr     r2, [r1, r0, lsl #2]
  70         \instr  r2, r2, r3
  71         str     r2, [r1, r0, lsl #2]
  72         restore_irqs ip
  73         mov     pc, lr
  74 UNWIND( .fnend          )
  75 ENDPROC(\name           )
  76         .endm
  77
  78 /**
  79  * testop - implement a test_and_xxx_bit operation.
  80  * @instr: operational instruction
  81  * @store: store instruction
  82  *
  83  * Note: we can trivially conditionalise the store instruction
  84  * to avoid dirtying the data cache.
  85  */
  86         .macro  testop, name, instr, store
  87 ENTRY(  \name           )
  88 UNWIND( .fnstart        )
  89         ands    ip, r1, #3
  90         strneb  r1, [ip]                @ assert word-aligned
  91         and     r3, r0, #31
  92         mov     r0, r0, lsr #5
  93         save_and_disable_irqs ip
  94         ldr     r2, [r1, r0, lsl #2]!
  95         mov     r0, #1
  96         tst     r2, r0, lsl r3
  97         \instr  r2, r2, r0, lsl r3
  98         \store  r2, [r1]
  99         moveq   r0, #0
 100         restore_irqs ip
 101         mov     pc, lr
 102 UNWIND( .fnend          )
 103 ENDPROC(\name           )
 104         .endm
 105 #endif