[PATCH v3] ARM: advertise availability of v8 Crypto instructions
Russell King - ARM Linux
linux at arm.linux.org.uk
Wed Mar 18 04:01:14 PDT 2015
On Tue, Mar 10, 2015 at 08:54:48AM +0100, Ard Biesheuvel wrote:
> @@ -393,6 +393,37 @@ static void __init cpuid_init_hwcaps(void)
> vmsa = (read_cpuid_ext(CPUID_EXT_MMFR0) & 0xf) >> 0;
> if (vmsa >= 5)
> elf_hwcap |= HWCAP_LPAE;
> + /*
> + * ID_ISAR5 contains 4-bit wide signed feature blocks.
> + * The blocks we test below represent incremental functionality
> + * for non-negative values. Negative values are reserved.
> + */
> + features = read_cpuid_ext(ID_ISAR5);
> + block = (features >> 4) & 0xf;
Okay, what I'd like to see is something like:
block = cpuid_feature_extract_field(features, 4);
with this in cputype.h:
static inline int cpuid_feature_extract_field(u32 features, unsigned int field)
int feature = (features >> field) & 15;
/* feature registers are signed values */
if (feature > 8)
feature -= 16;
We can then use proper signed tests in the code - and convert all tests
to use this helper.
FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up
according to speedtest.net.
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