arch/arm/lib/bitops.h

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