Re: [PATCH v1] xen/arm: arm32: Add support to identify the Cortex-R52 processor

[Julien Grall <julien@xxxxxxx>]

Hi,

On 20/06/2023 16:17, Ayan Kumar Halder wrote:
> Add a special configuration (CONFIG_AARCH32_V8R) to setup the Cortex-R52
> specifics.
>
> Cortex-R52 is an Arm-V8R AArch32 processor.
>
> Refer ARM DDI 0487I.a ID081822, G8-9647, G8.2.112 MIDR,
> bits[31:24] = 0x41 , Arm Ltd
> bits[23:20] = Implementation defined
> bits[19:16] = 0xf , Arch features are individually identified
> bits[15:4] = Implementation defined
> bits[3:0] = Implementation defined
>
> Thus, the processor id is 0x410f0000 and the processor id mask is
> 0xff0f0000
>
> Also, there is no special initialization required for R52.
Are you saying that Xen upstream + this patch will boot on Cortex-R52?

> Signed-off-by: Ayan Kumar Halder <ayan.kumar.halder@xxxxxxx>
> ---
>   xen/arch/arm/Kconfig         |  7 +++++++
>   xen/arch/arm/arm32/Makefile  |  1 +
>   xen/arch/arm/arm32/proc-v8.S | 32 ++++++++++++++++++++++++++++++++
>   3 files changed, 40 insertions(+)
>   create mode 100644 xen/arch/arm/arm32/proc-v8.S
>
> diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
> index 61e581b8c2..c45753a2dd 100644
> --- a/xen/arch/arm/Kconfig
> +++ b/xen/arch/arm/Kconfig
> @@ -3,6 +3,13 @@ config ARM_32
>         depends on "$(ARCH)" = "arm32"
>         select ARCH_MAP_DOMAIN_PAGE
>   
> +config AARCH32_V8R
> +       bool "AArch32 Arm V8R Support (UNSUPPORTED)" if UNSUPPORTED
> +       def_bool n
> +       depends on ARM_32
> +       help
> +         This option enables Armv8-R profile for AArch32.
> +
>   config ARM_64
>         def_bool y
>         depends on !ARM_32
> diff --git a/xen/arch/arm/arm32/Makefile b/xen/arch/arm/arm32/Makefile
> index 520fb42054..2ab808a7a8 100644
> --- a/xen/arch/arm/arm32/Makefile
> +++ b/xen/arch/arm/arm32/Makefile
> @@ -8,6 +8,7 @@ obj-y += head.o
>   obj-y += insn.o
>   obj-$(CONFIG_LIVEPATCH) += livepatch.o
>   obj-y += proc-v7.o proc-caxx.o
> +obj-$(CONFIG_AARCH32_V8R) += proc-v8.o
>   obj-y += smpboot.o
>   obj-y += traps.o
>   obj-y += vfp.o
> diff --git a/xen/arch/arm/arm32/proc-v8.S b/xen/arch/arm/arm32/proc-v8.S
> new file mode 100644
> index 0000000000..c5a566b165
> --- /dev/null
> +++ b/xen/arch/arm/arm32/proc-v8.S
Below you say the file will contain v8r specific initialization. So 
please rename it to proc-v8r.S.
Cheers,

--
Julien Grall