[PATCH v4 0/8] Add basic Boot Loader Interface support

[Oliver Steffen]

This is a step towards supporting unified kernel images (UKI) in Grub.

Add a new module named boot_loader_interface, which provides a command
with the same name. It implements a small but quite useful part of the
Boot Loader Interface [0].  This interface uses EFI variables for
communication between the boot loader and the operating system.

This module sets two EFI variables under the vendor GUID
4a67b082-0a4c-41cf-b6c7-440b29bb8c4f:

- LoaderInfo: contains GRUB + <version number>.
  This allows the running operating system to identify the boot loader
  used during boot.

- LoaderDevicePartUUID: contains the partition UUID of the
  EFI System Partition (ESP). This is used by
  systemd-gpt-auto-generator [1] to find the root partitions (and
  others too), via partition type IDs [2]. This is especially useful for
  UKIs, where the kernel command line is fixed and usually does not
  contain any information about the root partition.

This module is only available on EFI platforms.

This series also unifies the GUID implementations and introduces a
printf format specifier for them: %pG.

[0] https://systemd.io/BOOT_LOADER_INTERFACE/
[1] 
https://www.freedesktop.org/software/systemd/man/systemd-gpt-auto-generator.html
[2] 
https://uapi-group.org/specifications/specs/discoverable_partitions_specification/

v4:
- Place grub_utf8_to_utf16_alloc() in kern/misc.c and use it in kern/efi.c
- bli: rework partition GUID code, improve error reporting
- Add documentation for the bli module
- Address other comments

v3:
- https://mail.gnu.org/archive/html/grub-devel/2023-03/msg00008.html
- Unify GUID implementations for GPT and EFI
- Add printf format specifier for GUIDs, drop guid print function from
  v2.
- WIP/Please comment: Started extracting utf8->utf16 code.  Where should
  this go?
- Address other comments

v2:
- https://mail.gnu.org/archive/html/grub-devel/2023-02/msg00099.html
- Addressed comments from Daniel
- Added a print function for gpt guids`
- Added integer overflow check in UTF16 conversion
- Added config drop-in file that loads the module on EFI

v1:
- https://mail.gnu.org/archive/html/grub-devel/2023-01/msg00104.html

Oliver Steffen (8):
  efi: Add grub_efi_set_variable_with_attributes
  Unify GUID types
  kern/misc: Add a format specifier GUIDs.
  grub-core: Make use of guid printf format specifier
  types.h: Add GRUB_SSIZE_MAX
  kern/misc, kern/efi: Extract UTF-8 to UTF-16 code
  Add a module for the Boot Loader Interface
  util/grub.d: Activate bli module on EFI

 Makefile.util.def                    |   6 +
 docs/grub.texi                       |  22 ++++
 grub-core/Makefile.core.def          |   6 +
 grub-core/commands/acpi.c            |   4 +-
 grub-core/commands/bli.c             | 166 +++++++++++++++++++++++++++
 grub-core/commands/efi/efifwsetup.c  |   4 +-
 grub-core/commands/efi/loadbios.c    |  14 +--
 grub-core/commands/efi/lsefi.c       |  17 +--
 grub-core/commands/efi/lsefisystab.c |  10 +-
 grub-core/commands/efi/lssal.c       |   4 +-
 grub-core/commands/efi/smbios.c      |  12 +-
 grub-core/commands/efi/tpm.c         |   6 +-
 grub-core/commands/probe.c           |   9 +-
 grub-core/disk/efi/efidisk.c         |   4 +-
 grub-core/efiemu/i386/pc/cfgtables.c |   6 +-
 grub-core/efiemu/main.c              |   4 +-
 grub-core/efiemu/runtime/efiemu.c    |  14 +--
 grub-core/kern/efi/acpi.c            |  12 +-
 grub-core/kern/efi/efi.c             |  86 +++++---------
 grub-core/kern/efi/fdt.c             |   2 +-
 grub-core/kern/efi/init.c            |   2 +-
 grub-core/kern/efi/sb.c              |   4 +-
 grub-core/kern/misc.c                | 118 +++++++++++++++----
 grub-core/loader/arm64/linux.c       |   4 +-
 grub-core/loader/efi/fdt.c           |   2 +-
 grub-core/loader/i386/xnu.c          |  13 +--
 grub-core/loader/ia64/efi/linux.c    |   2 +-
 grub-core/net/drivers/efi/efinet.c   |   4 +-
 grub-core/term/efi/console.c         |   2 +-
 grub-core/term/efi/serial.c          |   2 +-
 grub-core/video/efi_gop.c            |   8 +-
 grub-core/video/efi_uga.c            |   2 +-
 include/grub/efi/api.h               |  69 +++++------
 include/grub/efi/efi.h               |  20 ++--
 include/grub/efiemu/efiemu.h         |  10 +-
 include/grub/efiemu/runtime.h        |   2 +-
 include/grub/misc.h                  |   3 +
 include/grub/types.h                 |  11 ++
 util/grub.d/25_bli.in                |  25 ++++
 39 files changed, 483 insertions(+), 228 deletions(-)
 create mode 100644 grub-core/commands/bli.c
 create mode 100644 util/grub.d/25_bli.in

-- 
2.39.2