Re: [RFC PATCH hurd] Add partial /proc/cpuinfo implementation

[Diego Nieto Cid]

Hi,

On Thu, Jan 09, 2025 at 11:51:27AM +0300, Sergey Bugaev wrote:
> 
> "Implementer", "architecture", "variant", "part", "revision" come from
> midr/revidr [0], and "features" are hwcap names. These are privileged
> registers that only EL1 can read, but on AArch64 gnumach, their values
> are obtainable from userland using the aarch64_get_hwcaps RPC (see
> gnumach:aarch64/include/mach/aarch64/mach_aarch64.defs and
> gnumach:aarch64/include/mach/aarch64/mach_aarch64_types.h).

Looking at the types.h header, I see there are HWCAP2_* definitions for
bits above 32. Since hwcaps_t is an uint32_t and the defs file claims to
return two values (I assume the first for HWCAP_* and the second for
HWCAP2_*), I don't see how to get the higher bits of HWCAP2_*.

How does that work?