linux-kernel - Re: [PATCH 3/3] efi/libstub: consider CONFIG

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Message-ID: <149af6cb-300c-af5e-2a91-161be0dd4d43@marek.ca>
Date: Sat, 12 Oct 2024 11:00:49 -0400
From: Jonathan Marek <jonathan@...ek.ca>
To: Ard Biesheuvel <ardb@...nel.org>
Cc: linux-efi@...r.kernel.org, open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/3] efi/libstub: consider CONFIG_CMDLINE for initrd= and
 dtb= options

On 10/12/24 10:50 AM, Ard Biesheuvel wrote:
...
> 
> Right.
> 
> Would the below work for you? It's not the prettiest code in the
> world, but at least it keeps the weird local to the function.
> 

Its missing the "load_options_size == 0" case, then CONFIG_CMDLINE 
should be used even if FORCE/etc. are not set. Otherwise it looks OK. 
(cmdline_len also shouldn't include the NUL character, but I don't think 
that matters)

> --- a/drivers/firmware/efi/libstub/file.c
> +++ b/drivers/firmware/efi/libstub/file.c
> @@ -189,26 +189,48 @@
>                                    unsigned long *load_addr,
>                                    unsigned long *load_size)
>   {
> -       const efi_char16_t *cmdline = efi_table_attr(image, load_options);
> -       u32 cmdline_len = efi_table_attr(image, load_options_size);
>          unsigned long efi_chunk_size = ULONG_MAX;
>          efi_file_protocol_t *volume = NULL;
> +       const efi_char16_t *cmdline;
>          efi_file_protocol_t *file;
>          unsigned long alloc_addr;
>          unsigned long alloc_size;
>          efi_status_t status;
> +       bool again = false;
> +       u32 cmdline_len;
>          int offset;
> 
>          if (!load_addr || !load_size)
>                  return EFI_INVALID_PARAMETER;
> 
> -       efi_apply_loadoptions_quirk((const void **)&cmdline, &cmdline_len);
> -       cmdline_len /= sizeof(*cmdline);
> -
>          if (IS_ENABLED(CONFIG_X86) && !efi_nochunk)
>                  efi_chunk_size = EFI_READ_CHUNK_SIZE;
> 
>          alloc_addr = alloc_size = 0;
> +
> +#ifdef CONFIG_CMDLINE
> +       if (IS_ENABLED(CONFIG_CMDLINE_FORCE) ||
> +           IS_ENABLED(CONFIG_CMDLINE_OVERRIDE) ||
> +           (again = (IS_ENABLED(CONFIG_X86) ||
> +                     IS_ENABLED(CONFIG_CMDLINE_EXTEND)))) {
> +               static const efi_char16_t builtin_cmdline[] = L""
> CONFIG_CMDLINE;
> +
> +               cmdline = builtin_cmdline;
> +               cmdline_len = sizeof(builtin_cmdline);
> +       } else
> +#endif
> +       {
> +do_load_options:
> +               cmdline = efi_table_attr(image, load_options);
> +               cmdline_len = efi_table_attr(image, load_options_size);
> +
> +               efi_apply_loadoptions_quirk((const void **)&cmdline,
> +                                           &cmdline_len);
> +
> +               again = false;
> +       }
> +       cmdline_len /= sizeof(*cmdline);
> +
>          do {
>                  struct finfo fi;
>                  unsigned long size;
> @@ -290,6 +312,9 @@
>                  efi_call_proto(volume, close);
>          } while (offset > 0);
> 
> +       if (again)
> +               goto do_load_options;
> +
>          *load_addr = alloc_addr;
>          *load_size = alloc_size;
>