[PATCH v11 10/14] riscv: hwprobe: Add thead vendor extension probing

[Yangyu Chen]

On 11/14/24 10:21, Charlie Jenkins wrote:
> Add a new hwprobe key "RISCV_HWPROBE_KEY_VENDOR_EXT_THEAD_0" which
> allows userspace to probe for the new RISCV_ISA_VENDOR_EXT_XTHEADVECTOR
> vendor extension.
> 

Hi Charlie,

How about changing the name of the key from 
"RISCV_ISA_VENDOR_EXT_XTHEADVECTOR" to "RISCV_HWPROBE_KEY_VENDOR_EXT_0" 
and use marchid to identify what the vendor is, each vendor will have 
its own bit definition in this value. So we can avoid adding so many 
hwprobe keys for each vendor in the future.

I proposed a commit here: 
https://github.com/cyyself/linux/commit/36390645d85d1ac75dd71172f167719df4297f59

> This new key will allow userspace code to probe for which thead vendor
> extensions are supported. This API is modeled to be consistent with
> RISCV_HWPROBE_KEY_IMA_EXT_0. The bitmask returned will have each bit
> corresponding to a supported thead vendor extension of the cpumask set.
> Just like RISCV_HWPROBE_KEY_IMA_EXT_0, this allows a userspace program
> to determine all of the supported thead vendor extensions in one call.
> 
> Signed-off-by: Charlie Jenkins <charlie at rivosinc.com>
> Reviewed-by: Evan Green <evan at rivosinc.com>
> ---
>   arch/riscv/include/asm/hwprobe.h                   |  3 +-
>   .../include/asm/vendor_extensions/thead_hwprobe.h  | 19 +++++++++++
>   .../include/asm/vendor_extensions/vendor_hwprobe.h | 37 ++++++++++++++++++++++
>   arch/riscv/include/uapi/asm/hwprobe.h              |  3 +-
>   arch/riscv/include/uapi/asm/vendor/thead.h         |  3 ++
>   arch/riscv/kernel/sys_hwprobe.c                    |  5 +++
>   arch/riscv/kernel/vendor_extensions/Makefile       |  1 +
>   .../riscv/kernel/vendor_extensions/thead_hwprobe.c | 19 +++++++++++
>   8 files changed, 88 insertions(+), 2 deletions(-)
>