diff options
| author |   Will Deacon <will.deacon@arm.com> | 2015-02-03 16:14:13 +0000 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2015-07-27 15:28:50 +0100 |
| commit | c09d6a04d17d730b0463207a26ece082772b59ee (patch) | |
| tree | 43aec4a96946d28bc0fd985b1219317bdcb2b8d2 /arch/arm64/kernel | |
| parent | arm64: introduce CONFIG_ARM64_LSE_ATOMICS as fallback to ll/sc atomics (diff) | |
| download | linux-dev-c09d6a04d17d730b0463207a26ece082772b59ee.tar.xz linux-dev-c09d6a04d17d730b0463207a26ece082772b59ee.zip | |
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>
Diffstat (limited to 'arch/arm64/kernel')
| -rw-r--r-- | arch/arm64/kernel/setup.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index f4fbbc884893..97785c01acbf 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -285,6 +285,9 @@ static void __init setup_processor(void) case 2: elf_hwcap |= HWCAP_ATOMICS; cpus_set_cap(ARM64_CPU_FEAT_LSE_ATOMICS); + if (IS_ENABLED(CONFIG_AS_LSE) && + IS_ENABLED(CONFIG_ARM64_LSE_ATOMICS)) + pr_info("LSE atomics supported\n"); case 1: /* RESERVED */ case 0: |