• Will Deacon's avatar
    locking/atomic, arch/arm64: Implement... · 2efe95fe
    Will Deacon authored
    locking/atomic, arch/arm64: Implement atomic{,64}_fetch_{add,sub,and,andnot,or,xor}{,_relaxed,_acquire,_release}() for LSE instructions
    
    Implement FETCH-OP atomic primitives, these are very similar to the
    existing OP-RETURN primitives we already have, except they return the
    value of the atomic variable _before_ modification.
    
    This is especially useful for irreversible operations -- such as
    bitops (because it becomes impossible to reconstruct the state prior
    to modification).
    
    This patch implements the LSE variants.
    Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
    Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
    Cc: Catalin Marinas <catalin.marinas@arm.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
    Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Steve Capper <steve.capper@arm.com>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: linux-arch@vger.kernel.org
    Cc: linux-arm-kernel@lists.infradead.org
    Cc: linux-kernel@vger.kernel.org
    Link: http://lkml.kernel.org/r/1461344493-8262-2-git-send-email-will.deacon@arm.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
    2efe95fe
atomic_lse.h 14.9 KB