LXR linux/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
   6ENTRY(  \name           )
   7UNWIND( .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
  201:      ldrex   r2, [r1]
  21        \instr  r2, r2, r3
  22        strex   r0, r2, [r1]
  23        cmp     r0, #0
  24        bne     1b
  25        bx      lr
  26UNWIND( .fnend          )
  27ENDPROC(\name           )
  28        .endm
  29
  30        .macro  testop, name, instr, store
  31ENTRY(  \name           )
  32UNWIND( .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
  461:      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
  552:      bx      lr
  56UNWIND( .fnend          )
  57ENDPROC(\name           )
  58        .endm
  59#else
  60        .macro  bitop, name, instr
  61ENTRY(  \name           )
  62UNWIND( .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
  75UNWIND( .fnend          )
  76ENDPROC(\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
  88ENTRY(  \name           )
  89UNWIND( .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
 103UNWIND( .fnend          )
 104ENDPROC(\name           )
 105        .endm
 106#endif
 107