On Mon, Apr 24, 2023 at 06:57:24PM +0200, Ard Biesheuvel wrote:
> In preparation for updating the EFI stub boot flow to avoid the bare
> metal decompressor code altogether, implement the support code for
> switching between 4 and 5 levels of paging before jumping to the kernel
> proper.
I must admit it is neat. I like it a lot.
Any chance we can share the code with the traditional decompressor?
There's not much that EFI specific here. It should be possible to isolate
it from the rest, no?
> @@ -792,6 +925,14 @@ asmlinkage unsigned long efi_main(efi_handle_t handle,
> (get_efi_config_table(ACPI_20_TABLE_GUID) ?:
> get_efi_config_table(ACPI_TABLE_GUID));
>
> +#ifdef CONFIG_X86_64
> + status = efi_setup_5level_paging();
> + if (status != EFI_SUCCESS) {
> + efi_err("efi_setup_5level_paging() failed!\n");
> + goto fail;
> + }
> +#endif
> +
> /*
> * If the kernel isn't already loaded at a suitable address,
> * relocate it.
> @@ -910,6 +1051,10 @@ asmlinkage unsigned long efi_main(efi_handle_t handle,
> goto fail;
> }
>
> +#ifdef CONFIG_X86_64
> + efi_5level_switch();
> +#endif
> +
> return bzimage_addr;
> fail:
> efi_err("efi_main() failed!\n");
Maybe use IS_ENABLED() + dummy efi_setup_5level_paging()/efi_5level_switch()
instead of #ifdefs?
--
Kiryl Shutsemau / Kirill A. Shutemov
