arm64: atomics: patch in lse instructions when supported by the CPU
authorWill Deacon <will.deacon@arm.com>
Tue, 3 Feb 2015 16:14:13 +0000 (16:14 +0000)
committerWill Deacon <will.deacon@arm.com>
Mon, 27 Jul 2015 14:28:50 +0000 (15:28 +0100)
commitc09d6a04d17d730b0463207a26ece082772b59ee
tree43aec4a96946d28bc0fd985b1219317bdcb2b8d2
parentc0385b24af15020a1e505f2c984db0d7c0d017e1
arm64: atomics: patch in lse instructions when supported by the CPU

On CPUs which support the LSE atomic instructions introduced in ARMv8.1,
it makes sense to use them in preference to ll/sc sequences.

This patch introduces runtime patching of atomic_t and atomic64_t
routines so that the call-site for the out-of-line ll/sc sequences is
patched with an LSE atomic instruction when we detect that
the CPU supports it.

If binutils is not recent enough to assemble the LSE instructions, then
the ll/sc sequences are inlined as though CONFIG_ARM64_LSE_ATOMICS=n.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
arch/arm64/Makefile
arch/arm64/include/asm/atomic.h
arch/arm64/include/asm/atomic_ll_sc.h
arch/arm64/include/asm/atomic_lse.h
arch/arm64/include/asm/lse.h [new file with mode: 0644]
arch/arm64/kernel/setup.c