Re: [PATCH 1/2] arm64: Move firmware fdt search into global function

[Andrei Borzenkov <arvidjaar@gmail.com>]

29.02.2016 02:22, Alexander Graf пишет:
> Searching for a device tree that EFI passes to us via configuration tables
> is nothing architecture specific. Move it into generic code.
> 
> Signed-off-by: Alexander Graf <agraf@suse.de>
> ---
>  grub-core/kern/efi/init.c    | 22 ++++++++++++++++++++++
>  grub-core/loader/arm64/fdt.c | 24 +-----------------------
>  include/grub/efi/efi.h       |  2 ++
>  3 files changed, 25 insertions(+), 23 deletions(-)
> 
> diff --git a/grub-core/kern/efi/init.c b/grub-core/kern/efi/init.c
> index e9c85de..fb90ecd 100644
> --- a/grub-core/kern/efi/init.c
> +++ b/grub-core/kern/efi/init.c
> @@ -72,6 +72,28 @@ grub_machine_get_bootlocation (char **device, char **path)
>      }
>  }
>  
> +void *
> +grub_efi_get_firmware_fdt (void)
> +{
> +  grub_efi_configuration_table_t *tables;
> +  grub_efi_guid_t fdt_guid = GRUB_EFI_DEVICE_TREE_GUID;
> +  void *firmware_fdt = NULL;
> +  unsigned int i;
> +
> +  /* Look for FDT in UEFI config tables. */
> +  tables = grub_efi_system_table->configuration_table;
> +
> +  for (i = 0; i < grub_efi_system_table->num_table_entries; i++)
> +    if (grub_memcmp (&tables[i].vendor_guid, &fdt_guid, sizeof (fdt_guid)) == 0)
> +      {
> +	firmware_fdt = tables[i].vendor_table;
> +	grub_dprintf ("linux", "found registered FDT @ %p\n", firmware_fdt);
> +	break;
> +      }
> +
> +  return firmware_fdt;
> +}
> +

Is it relevant for x86? I cannot even find anything related to FDT or
"device tree" in UEFI spec, it falls under vendor extensions. What other
use it has except in Linux loader?

I really fail to see why it should be moved into core until at least one
more non-trivial caller is present.

>  void
>  grub_efi_fini (void)
>  {
> diff --git a/grub-core/loader/arm64/fdt.c b/grub-core/loader/arm64/fdt.c
> index 5202c14..db49cf6 100644
> --- a/grub-core/loader/arm64/fdt.c
> +++ b/grub-core/loader/arm64/fdt.c
> @@ -28,28 +28,6 @@
>  static void *loaded_fdt;
>  static void *fdt;
>  
> -static void *
> -get_firmware_fdt (void)
> -{
> -  grub_efi_configuration_table_t *tables;
> -  grub_efi_guid_t fdt_guid = GRUB_EFI_DEVICE_TREE_GUID;
> -  void *firmware_fdt = NULL;
> -  unsigned int i;
> -
> -  /* Look for FDT in UEFI config tables. */
> -  tables = grub_efi_system_table->configuration_table;
> -
> -  for (i = 0; i < grub_efi_system_table->num_table_entries; i++)
> -    if (grub_memcmp (&tables[i].vendor_guid, &fdt_guid, sizeof (fdt_guid)) == 0)
> -      {
> -	firmware_fdt = tables[i].vendor_table;
> -	grub_dprintf ("linux", "found registered FDT @ %p\n", firmware_fdt);
> -	break;
> -      }
> -
> -  return firmware_fdt;
> -}
> -
>  void *
>  grub_fdt_load (grub_size_t additional_size)
>  {
> @@ -65,7 +43,7 @@ grub_fdt_load (grub_size_t additional_size)
>    if (loaded_fdt)
>      raw_fdt = loaded_fdt;
>    else
> -    raw_fdt = get_firmware_fdt();
> +    raw_fdt = grub_efi_get_firmware_fdt();
>  
>    size =
>      raw_fdt ? grub_fdt_get_totalsize (raw_fdt) : GRUB_FDT_EMPTY_TREE_SZ;
> diff --git a/include/grub/efi/efi.h b/include/grub/efi/efi.h
> index 0e6fd86..2acf85e 100644
> --- a/include/grub/efi/efi.h
> +++ b/include/grub/efi/efi.h
> @@ -81,6 +81,8 @@ extern void (*EXPORT_VAR(grub_efi_net_config)) (grub_efi_handle_t hnd,
>  						char **device,
>  						char **path);
>  
> +void *EXPORT_FUNC(grub_efi_get_firmware_fdt)(void);
> +
>  grub_addr_t grub_efi_modules_addr (void);
>  
>  void grub_efi_mm_init (void);
>