kernel-ark/arch/arm/lib/bitops.h
Russell King e7ec02938d [ARM SMP] Fix another ARMv6 bitop problem
We sometimes forgot to check whether the exclusive store succeeded.
Ensure that we always check.  Also ensure that we always use the
out of line versions, since the inline versions are not SMP safe.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-07-28 20:36:26 +01:00

65 lines
1.2 KiB
C

#if __LINUX_ARM_ARCH__ >= 6
.macro bitop, instr
mov r2, #1
and r3, r0, #7 @ Get bit offset
add r1, r1, r0, lsr #3 @ Get byte offset
mov r3, r2, lsl r3
1: ldrexb r2, [r1]
\instr r2, r2, r3
strexb r0, r2, [r1]
cmp r0, #0
bne 1b
mov pc, lr
.endm
.macro testop, instr, store
and r3, r0, #7 @ Get bit offset
mov r2, #1
add r1, r1, r0, lsr #3 @ Get byte offset
mov r3, r2, lsl r3 @ create mask
1: ldrexb r2, [r1]
ands r0, r2, r3 @ save old value of bit
\instr r2, r2, r3 @ toggle bit
strexb ip, r2, [r1]
cmp ip, #0
bne 1b
cmp r0, #0
movne r0, #1
2: mov pc, lr
.endm
#else
.macro bitop, instr
and r2, r0, #7
mov r3, #1
mov r3, r3, lsl r2
save_and_disable_irqs ip, r2
ldrb r2, [r1, r0, lsr #3]
\instr r2, r2, r3
strb r2, [r1, r0, lsr #3]
restore_irqs ip
mov pc, lr
.endm
/**
* testop - implement a test_and_xxx_bit operation.
* @instr: operational instruction
* @store: store instruction
*
* Note: we can trivially conditionalise the store instruction
* to avoid dirting the data cache.
*/
.macro testop, instr, store
add r1, r1, r0, lsr #3
and r3, r0, #7
mov r0, #1
save_and_disable_irqs ip, r2
ldrb r2, [r1]
tst r2, r0, lsl r3
\instr r2, r2, r0, lsl r3
\store r2, [r1]
restore_irqs ip
moveq r0, #0
mov pc, lr
.endm
#endif