Add devicetree-auto support for UKI

This adds support for matching multiple devicetrees in the `Devicetree`
config option by using globs, and appending each one to a UKI with
dtbauto. This does **not** support type 1 booting.

Fixes #3827

Author: craftyguy

mkosi/__init__.py

@@ -7,6 +7,7 @@
 import hashlib
 import itertools
 import json
+import glob
 import logging
 import os
 import re
@@ -90,7 +91,7 @@
 from mkosi.installer import clean_package_manager_metadata
 from mkosi.installer.pacman import Pacman
 from mkosi.installer.zypper import Zypper
-from mkosi.kmod import gen_required_kernel_modules, is_valid_kdir, loaded_modules, process_kernel_modules
+from mkosi.kmod import gen_required_kernel_modules, is_valid_kdir, loaded_modules, process_kernel_modules, globs_match_filename
 from mkosi.log import ARG_DEBUG, complete_step, die, log_notice, log_step
 from mkosi.manifest import Manifest
 from mkosi.mounts import (
@@ -1598,6 +1599,7 @@ def build_kernel_modules_initrd(context: Context, kver: str) -> Path:
 
 def find_devicetree(context: Context, kver: str) -> Path:
     assert context.config.devicetree
+    assert not glob.has_magic(os.fspath(context.config.devicetree))
 
     for d in (
         context.root / f"usr/lib/firmware/{kver}/device-tree",
@@ -1611,6 +1613,38 @@ def find_devicetree(context: Context, kver: str) -> Path:
     die(f"Requested devicetree {context.config.devicetree} not found")
 
 
+
+def find_devicetrees(context: Context, kver: str) -> list[Path]:
+    assert context.config.devicetree
+
+    if not glob.has_magic(os.fspath(context.config.devicetree)):
+        # Single devicetree
+        return [find_devicetree(context, kver)]
+
+    # Glob pattern - search all directories
+    dtb_dirs = [
+        context.root / f"usr/lib/firmware/{kver}/device-tree",
+        context.root / f"usr/lib/linux-image-{kver}",
+        context.root / f"usr/lib/modules/{kver}/dtb",
+    ]
+
+    matched_dtbs = []
+    for dtb_dir in dtb_dirs:
+        if not dtb_dir.exists():
+            continue
+
+        all_dtbs = [p for p in dtb_dir.rglob("*.dtb") if p.is_file()]
+        for dtb in all_dtbs:
+            rel_path = os.fspath(dtb.relative_to(dtb_dir))
+            if globs_match_filename(rel_path, [os.fspath(context.config.devicetree)], match_default=False):
+                matched_dtbs.append(dtb)
+
+    if not matched_dtbs:
+        logging.warning(f"Devicetree glob '{context.config.devicetree}' matched 0 files")
+
+    return matched_dtbs
+
+
 def want_signed_pcrs(config: Config) -> bool:
     return config.sign_expected_pcr == ConfigFeature.enabled or (
         config.sign_expected_pcr == ConfigFeature.auto
@@ -1769,9 +1803,14 @@ def build_uki(
     ]  # fmt: skip
 
     if context.config.devicetree:
-        dtb = find_devicetree(context, kver)
-        arguments += ["--devicetree", workdir(dtb)]
-        options += ["--ro-bind", dtb, workdir(dtb)]
+        if glob.has_magic(os.fspath(context.config.devicetree)):
+            for dtb in find_devicetrees(context, kver):
+                arguments += ["--devicetree-auto", workdir(dtb)]
+                options += ["--ro-bind", dtb, workdir(dtb)]
+        else:
+            dtb = find_devicetree(context, kver)
+            arguments += ["--devicetree", workdir(dtb)]
+            options += ["--ro-bind", dtb, workdir(dtb)]
 
     if context.config.splash:
         splash = context.root / os.fspath(context.config.splash).lstrip("/")
@@ -2016,6 +2055,8 @@ def install_type1(
 
     dtb = None
     if context.config.devicetree:
+        if glob.has_magic(os.fspath(context.config.devicetree)):
+            die("Devicetree globs are not supported with Type 1 boot entries, use UKI builds instead")
         dtb = dst / context.config.devicetree
         with umask(~0o700):
             dtb.parent.mkdir(parents=True, exist_ok=True)

mkosi/resources/man/mkosi.1.md

@@ -1085,6 +1085,9 @@ boolean argument: either `1`, `yes`, or `true` to enable, or `0`, `no`,
     instead of the one provided by firmware. **mkosi** will search for the
     specified file relative to common paths where Linux distributions install
     Devicetree files. It should typically have the format `<vendor>/<board>.dtb`.
+    When this includes globs, multiple dtbs may be included **only** when building a UKI.
+    Internally this uses the dtbauto feature. Using globs/dtbauto is is **not**
+    supported for Type 1 booting.
 
 `Splash=`, `--splash=`
 :   When set, the boot splash for any unified kernel image built by **mkosi** will