On Fri, 15 Mar 2024 at 01:27, Tim Schumacher <timschumi@xxxxxx> wrote:
>
> The structure was moved to the efivarfs internals in commit 2d82e6227ea1
> ("efi: vars: Move efivar caching layer into efivarfs") after previously
> being used as the data ABI for efivars until its removal in commit
> 0f5b2c69a4cb ("efi: vars: Remove deprecated 'efivars' sysfs interface").
>
> As efivarfs only uses the structure for the variable name caching layer,
> the data-related members were never in use. Remove them to avoid
> implying that efivarfs is bound by the same restrictions that efivars
> once had.
>
> Since we are changing the last copy of "struct efi_variable", document
> the former layout in the ABI documentation of /sys/firmware/efi/vars
> that is still left over.
>
> Signed-off-by: Tim Schumacher <timschumi@xxxxxx>
> ---
> I'm unsure if this is how documentation of removed interfaces is/should
> be handled, input on this would be greatly appreciated. Of course, the
> alternative to what I did here is to remove the documentation
> completely. If someone is running a kernel old enough to have this
> interface, then the matching kernel source will still contain said
> documentation.
> ---
> Documentation/ABI/stable/sysfs-firmware-efi-vars | 12 ++++++++++--
> fs/efivarfs/internal.h | 3 ---
> 2 files changed, 10 insertions(+), 5 deletions(-)
>
Please just rip out the doc (but in a separate patch and cc the
Documentation maintainers)
> diff --git a/Documentation/ABI/stable/sysfs-firmware-efi-vars b/Documentation/ABI/stable/sysfs-firmware-efi-vars
> index 46ccd233e359..461b9139cedb 100644
> --- a/Documentation/ABI/stable/sysfs-firmware-efi-vars
> +++ b/Documentation/ABI/stable/sysfs-firmware-efi-vars
> @@ -41,8 +41,16 @@ Description:
> raw_var: A binary file that can be read to obtain
> a structure that contains everything
> there is to know about the variable.
> - For structure definition see "struct
> - efi_variable" in the kernel sources.
> +
> + The structure is defined as follows:
> + struct efi_variable {
> + efi_char16_t VariableName[512];
> + efi_guid_t VendorGuid;
> + unsigned long DataSize;
> + __u8 Data[1024];
> + efi_status_t Status;
> + __u32 Attributes;
> + } __attribute__((packed));
>
> This file can also be written to in
> order to update the value of a variable.
> diff --git a/fs/efivarfs/internal.h b/fs/efivarfs/internal.h
> index f7206158ee81..971560a01320 100644
> --- a/fs/efivarfs/internal.h
> +++ b/fs/efivarfs/internal.h
> @@ -24,9 +24,6 @@ struct efivarfs_fs_info {
> struct efi_variable {
> efi_char16_t VariableName[EFI_VAR_NAME_LEN/sizeof(efi_char16_t)];
> efi_guid_t VendorGuid;
> - unsigned long DataSize;
> - __u8 Data[1024];
> - efi_status_t Status;
> __u32 Attributes;
> } __attribute__((packed));
>
I suppose we can drop the packed attribute too, given that this is no
longer external ABI.
