Re: [PATCH v2 2/7] init: add DPS root partition type UUID definitions

[Vincent Mailhol <mailhol@kernel.org>]

On 25/10/2026 at 14:13, sashiko-bot@kernel.org wrote:
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [Medium] init: DPS_ROOT_PARTITION_TYPE_UUID sets 64-bit UUID on 32-bit LOONGARCH
> --
> 
> commit 109ce0d2c6fc812a6bc94f72e97807013dc5fc56
> Author: Vincent Mailhol <mailhol@kernel.org>
> 
> init: add DPS root partition type UUID definitions
> 
> This commit adds the hidden DPS_ROOT_PARTITION_TYPE_UUID string Kconfig
> symbol populated with the Discoverable Partitions Specification root
> partition type UUIDs for EFI-supported architectures, along with the
> derived DPS_ROOT_AUTO_DISCOVERY boolean symbol.
> 
> Link: https://uapi-group.org/specifications/specs/discoverable_partitions_specification/
> 
>> diff --git a/init/Kconfig b/init/Kconfig
>> index b31aa298c4fe5..133854355697b 100644
>> --- a/init/Kconfig
>> +++ b/init/Kconfig
>> @@ -2166,6 +2166,20 @@ config ARCH_HAS_PREPARE_SYNC_CORE_CMD
>>  config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
>>  	bool
>>  
>> +config DPS_ROOT_PARTITION_TYPE_UUID
>> +	depends on EFI && EFI_PARTITION
>> +	string
>> +	default "69dad710-2ce4-4e3c-b16c-21a1d49abed3" if ARM
>> +	default "b921b045-1df0-41c3-af44-4c6f280d3fae" if ARM64
>> +	default "77055800-792c-4f94-b39a-98c91b762bb6" if LOONGARCH
> 
> [Severity: Medium]
> Should the LOONGARCH default also depend on 64BIT, matching the RISCV &&
> 64BIT check on the next line?
> 
> The UUID 77055800-792c-4f94-b39a-98c91b762bb6 is defined by the
> Discoverable Partitions Specification specifically for 64-bit LoongArch
> (SD_GPT_ROOT_LOONGARCH64), and the specification does not define a root
> partition type UUID for 32-bit LoongArch.

I see. I overlooked the 32-bit LoongArch case because DPS only defines
partition type UUIDs for LoongArch64. I will add a 64BIT guard in v3:

	default "77055800-792c-4f94-b39a-98c91b762bb6" if LOONGARCH && 64BIT

I will wait for further review comments before posting v3.

> In arch/loongarch/Kconfig, config LOONGARCH unconditionally selects EFI and
> supports both 32-bit and 64-bit kernel builds (such as
> arch/loongarch/configs/loongson32_defconfig):
> 
> arch/loongarch/Kconfig:
> config LOONGARCH
>     ...
> 	select EFI
> 	select GENERIC_ATOMIC64 if 32BIT
>     ...
> config 32BIT
> 	bool "32-bit kernel"
> 
> config 64BIT
> 	bool "64-bit kernel"
> 
> When building a 32-bit LoongArch kernel (CONFIG_LOONGARCH=y, CONFIG_32BIT=y,
> CONFIG_EFI=y, and CONFIG_EFI_PARTITION=y), DPS_ROOT_PARTITION_TYPE_UUID gets
> populated with the 64-bit LoongArch UUID and DPS_ROOT_AUTO_DISCOVERY is
> enabled. Because a 32-bit LoongArch kernel sets elf_check_arch to
> elf32_check_arch in arch/loongarch/include/asm/elf.h and only loads
> ELFCLASS32 binaries, wouldn't early_lookup_dps_root() auto-discover and
> mount a 64-bit LoongArch root partition when root= is omitted, and then fail
> to execute its 64-bit userspace?


Yours sincerely,
Vincent Mailhol