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arm64: klib: bitops: fix unpredictable stxr usage 

We're currently relying on unpredictable behaviour in our testops
(test_and_*_bit), as stxr is unpredictable when the status register and
the source register are the same

This patch changes reallocates the status register so as to bring us back into
the realm of predictable behaviour. Boot tested on an AEMv8 model.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Mark Rutland 2013-04-30 11:11:15 +01:00 committed by Catalin Marinas
parent 1ae90e7905
commit c47d6a04e6
1 changed files with 2 additions and 2 deletions
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arch/arm64/lib/bitops.S
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@ -50,8 +50,8 @@ ENTRY( \name )
1: ldxr x2, [x1]
lsr x0, x2, x3 // Save old value of bit
\instr x2, x2, x4 // toggle bit
stxr w2, x2, [x1]
cbnz w2, 1b
stxr w5, x2, [x1]
cbnz w5, 1b
smp_dmb ish
and x0, x0, #1
3: ret