Re: [PATCH v6 1/8] efi: Pass KHO state to the next kernel in a configuration table

[sashiko-bot@kernel.org]

> From: George Guo <guodongtai@kylinos.cn>
> 
> KHO has to give the next kernel two addresses: the KHO FDT and the
> bootmem area list. arm64 and riscv put them under /chosen in the boot
> FDT. LoongArch systems booting with EFI and ACPI do not require a boot
> FDT, so KHO needs another way to pass this information.
> 
> Add a Linux EFI configuration table for them, under
> LINUX_EFI_KEXEC_HANDOVER_GUID. It points to a struct linux_efi_kho_data.
> 
>   - On a cold boot, the LoongArch EFI stub installs the table, zeroed.
>     Each kexec'd kernel is given the same EFI system table, so it finds
>     the same table.
> 
>   - In early boot, efi_config_parse_tables() reserves the table so
>     neither the page allocator nor kexec segments use it, and calls
>     kho_populate() if the table holds KHO state.
> 
>   - Provide efi_kho_update() to update the table before kexec. Map the
>     table during boot so updates do not require allocation or mapping
>     at panic time.
> 
>   - efi_kho_table_found() tells architecture code whether the table was
>     found at boot, so it can turn KHO off when the table is missing.
> 
> Only the LoongArch stub installs the table, and only with
> CONFIG_KEXEC_HANDOVER. Elsewhere there is no table and this code does
> nothing.
> 
> Signed-off-by: George Guo <guodongtai@kylinos.cn>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261029172956.20791-1-dongtai.guo@linux.dev?part=1