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