[PATCH v4 1/3] arm64/hwcap: Document allocation of upper bits of AT_HWCAP
Szabolcs Nagy
szabolcs.nagy at arm.com
Thu Jul 7 02:00:53 PDT 2022
The 07/06/2022 18:52, Mark Brown wrote:
> The top two bits of AT_HWCAP are reserved for use by glibc and the rest of
> the top 32 bits are being kept unallocated for potential use by glibc.
> Document this in the header.
>
> Signed-off-by: Mark Brown <broonie at kernel.org>
> ---
> arch/arm64/include/uapi/asm/hwcap.h | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h
> index 4bb2cc8ac446..cc2ccd0a9edf 100644
> --- a/arch/arm64/include/uapi/asm/hwcap.h
> +++ b/arch/arm64/include/uapi/asm/hwcap.h
> @@ -19,6 +19,9 @@
>
> /*
> * HWCAP flags - for AT_HWCAP
> + *
> + * Bits 60 and 61 are reserved for use by libc.
should be 62 and 63
> + * Bits 32-59 are unallocated for potential use by libc.
32-61
> */
> #define HWCAP_FP (1 << 0)
> #define HWCAP_ASIMD (1 << 1)
> --
> 2.30.2
>
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