Commit c47d6a04 authored Apr 30, 2013 by Mark Rutland Committed by Catalin Marinas Apr 30, 2013

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>

parent 1ae90e79

arch/arm64/lib/bitops.S

+2 −2

Original line number	Diff line number	Diff line
		@@ -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