The bitops prototype use an 'int' as the bit index type but the asm
implementation assume it to be a 'long'. Since the compiler does not
guarantee zeroing the upper 32-bits in a register when used as 'int',
change the bitops implementation accordingly.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

This patch changes the test_and_*_bit functions to use the
load-acquire/store-release instructions instead of explicit DMB.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

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: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

This patch implements the AArch64-specific atomic bitops functions using
exclusive memory accesses to avoid locking.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>