Merge pull request #75 from keszybz/reconcile-s-g-a-g-and-d-p-s-and-b…

…-l-s

Reconcile the handling of /boot and /efi in BLS and DPS

specs/boot_loader_specification.md

@@ -112,9 +112,14 @@ These partitions shall be determined during _installation time_, and
 
 ### Mount Points
 
-It is recommended to mount `$BOOT` to `/boot/`, and the ESP to `/efi/`. If
-`$BOOT` and the ESP are the same, then either a bind mount or a symlink should
-be established making the partition available under both paths.
+It is recommended to mount `$BOOT` (either XBOOTLDR or the ESP) to `/boot/`.
+If both XBOOTLDR and the ESP are present, the ESP should be mounted to `/efi/`.
+
+Effectively, this means that
+`/boot/` is the location where new boot entries shall be written to.
+For the boot loader itself, the situation is more complicated,
+because its files may be located under `/boot/` or `/efi/`,
+depending on whether XBOOTLDR exists.
 
 (Mounting the ESP to `/boot/efi/`, as was traditionally done, is not
 recommended. Such a nested setup complicates an implementation via direct

specs/discoverable_partitions_specification.md

@@ -156,8 +156,8 @@ boot loader communicates this information to the OS, by implementing the
 | _`/usr/` Verity Signature Partition (TILE-Gx)_ | `4ede75e2-6ccc-4cc8-b9c7-70334b087510` `SD_GPT_USR_TILEGX_VERITY_SIG` | ditto | ditto |
 | _`/usr/` Verity Signature Partition (amd64/x86_64)_ | `e7bb33fb-06cf-4e81-8273-e543b413e2e2` `SD_GPT_USR_X86_64_VERITY_SIG` | ditto | ditto |
 | _`/usr/` Verity Signature Partition (x86)_ | `974a71c0-de41-43c3-be5d-5c5ccd1ad2c0` `SD_GPT_USR_X86_VERITY_SIG` | ditto | ditto |
-| _EFI System Partition_ | `c12a7328-f81f-11d2-ba4b-00a0c93ec93b` `SD_GPT_ESP` | VFAT | The ESP used for the current boot is automatically mounted to `/efi/` (or `/boot/` as fallback), unless a different partition is mounted there (possibly via `/etc/fstab`, or because the Extended Boot Loader Partition — see below — exists) or the directory is non-empty on the root disk.  This partition type is defined by the [UEFI Specification](http://www.uefi.org/specifications). |
-| _Extended Boot Loader Partition_ | `bc13c2ff-59e6-4262-a352-b275fd6f7172` `SD_GPT_XBOOTLDR` | Typically VFAT | The Extended Boot Loader Partition (XBOOTLDR) used for the current boot is automatically mounted to `/boot/`, unless a different partition is mounted there (possibly via `/etc/fstab`) or the directory is non-empty on the root disk. This partition type is defined by the [Boot Loader Specification](https://systemd.io/BOOT_LOADER_SPECIFICATION). |
+| _EFI System Partition_ | `c12a7328-f81f-11d2-ba4b-00a0c93ec93b` `SD_GPT_ESP` | VFAT | The ESP used for the current boot is automatically mounted to `/boot/` or `/efi/`, unless a different partition is mounted there (possibly via `/etc/fstab`) or the mount point directory is non-empty on the root disk. If both ESP and XBOOTLDR exist, the `/efi/` mount point shall be used for ESP. This partition type is defined by the [UEFI Specification](http://www.uefi.org/specifications). |
+| _Extended Boot Loader Partition_ | `bc13c2ff-59e6-4262-a352-b275fd6f7172` `SD_GPT_XBOOTLDR` | Typically VFAT | The Extended Boot Loader Partition (XBOOTLDR) used for the current boot is automatically mounted to `/boot/`, unless a different partition is mounted there (possibly via `/etc/fstab`) or the mount point directory is non-empty on the root disk. This partition type is defined by the [Boot Loader Specification](https://systemd.io/BOOT_LOADER_SPECIFICATION). |
 | _Swap_ | `0657fd6d-a4ab-43c4-84e5-0933c84b4f4f` `SD_GPT_SWAP` | Swap, optionally in LUKS | All swap partitions on the disk containing the root partition are automatically enabled. If the partition is encrypted with LUKS, the device mapper file will be named `/dev/mapper/swap`. This partition type predates the Discoverable Partitions Specification. |
 | _Home Partition_ | `933ac7e1-2eb4-4f13-b844-0e14e2aef915` `SD_GPT_HOME` | Any native, optionally in LUKS | The first partition with this type UUID on the disk containing the root partition is automatically mounted to `/home/`. If the partition is encrypted with LUKS, the device mapper file will be named `/dev/mapper/home`. |
 | _Server Data Partition_ | `3b8f8425-20e0-4f3b-907f-1a25a76f98e8` `SD_GPT_SRV` | Any native, optionally in LUKS | The first partition with this type UUID on the disk containing the root partition is automatically mounted to `/srv/`. If the partition is encrypted with LUKS, the device mapper file will be named `/dev/mapper/srv`. |