Re: [PATCH 1/3] arm64/cpufeature.h: Add macros for a cpu features testing

From: Suzuki K. Poulose
Date: Fri Sep 04 2015 - 08:00:22 EST

On 03/09/15 19:11, Alexander Kuleshov wrote:
This patch provides a couple of macros for the testing of processor
features (crypto and FP/SIMD) like support of SHA1, AES instructions,
support for FPU and etc. There is already a couple of places in the
arch/arm64/kernel where these processor features are tested and these
macros are facilitate this.

Signed-off-by: Alexander Kuleshov <kuleshovmail@xxxxxxxxx>
arch/arm64/include/asm/cpufeature.h | 44 +++++++++++++++++++++++++++++++++++++
1 file changed, 44 insertions(+)

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index c104421..2919455 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -28,7 +28,50 @@

#define ARM64_NCAPS 4

+ * ID_AA64ISAR0_EL1 AES, bits [7:4]
+ */
+#define ID_AA64ISAR0_EL1_AES_MASK 4
+#define ID_AA64ISAR0_EL1_AES(feature) \
+ (((feature >> ID_AA64ISAR0_EL1_AES_MASK) & 0xf) & 1UL)
+#define ID_AA64ISAR0_EL1_PMULL(feature) \
+ (((feature >> ID_AA64ISAR0_EL1_AES_MASK) & 0xf) & 2UL)

There is generic CPUID feature helper queued for 4.3, which can extract
the feature bits

cpuid_feature_extract_field(feature, shift)

You might want to use it instead. Btw, I have a patch series(waiting for
the merge window, before I post), which changes the way we initialise the
HWCAP bits.


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