Commit graph

2 commits

Author SHA1 Message Date
Heinrich Schuchardt
3a0654ecd0 efi_loader: correctly identify binary name
Only on the sandbox the default EFI binary name (e.g. BOOTX64.EFI) must
match the host architecture.

In all other cases we must use the target architecture.

Use #elif where appropriate.

Reported-by: Vagrant Cascadian <vagrant@reproducible-builds.org>
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
2022-06-12 09:17:54 +02:00
AKASHI Takahiro
4e65ca00f3 efi_loader: bootmgr: add booting from removable media
Under the current implementation, booting from removable media using
a architecture-specific default image name, say BOOTAA64.EFI, is
supported only in distro_bootcmd script. See the commit 74522c898b
("efi_loader: Add distro boot script for removable media").

This is, however, half-baked implementation because
1) UEFI specification requires this feature to be implemented as part
   of Boot Manager's responsibility:

  3 - Boot Manager
  3.5.1 Boot via the Simple File Protocol
  When booting via the EFI_SIMPLE_FILE_SYSTEM_PROTOCOL, the FilePath will
  start with a device path that points to the device that implements the
  EFI_SIMPLE_FILE_SYSTEM_PROTOCOL or the EFI_BLOCK_IO_PROTOCOL. The next
  part of the FilePath may point to the file name, including
  subdirectories, which contain the bootable image. If the file name is
  a null device path, the file name must be generated from the rules
  defined below.
  ...
  3.5.1.1 Removable Media Boot Behavior
  To generate a file name when none is present in the FilePath, the
  firmware must append a default file name in the form
  \EFI\BOOT\BOOT{machine type short-name}.EFI ...

2) So (1) entails the hehavior that the user's preference of boot media
   order should be determined by Boot#### and BootOrder variables.

With this patch, the semantics mentioned above is fully implemented.
For example, if you want to boot the system from USB and SCSI in this
order,
* define Boot0001 which contains only a device path to the USB device
  (without any file path/name)
* define Boot0002 which contains only a device path to the SCSI device,
and
* set BootOrder to Boot0001:Boot0002

To avoid build error for sandbox, default file name "BOOTSANDBOX.efi"
is defined even if it is out of scope of UEFI specification.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
On sandbox use binary name corresponding to host architecture.
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
2022-05-03 21:39:22 +02:00