Kleaf: Add support to create a modules.order files for images

* This is done by keeping a local copy of the make generated one, for
  each ddk_module or kernel_module. For kernel_module_group or
  kernel_modules_install this becomes a depset which is traversed in
  postorder (dependencies first) when needed.

* With this change kernel_images (initiramfs, (system|vendor)_dlkm) can
  control whether to use this new approach or keep the old behavior with
  the variable `create_modules_order` (set to True by default).

Bug: 306122000
Change-Id: Ic636c2da8d77e6c25e7eb9c8f6de68904828a9ad
Signed-off-by: Ulises Mendez Martinez <umendez@google.com>
(cherry picked from commit 1d3379dd0e0bb660bff2903ce7e93bd93e696700)

7 files changed, 61 insertions, 3 deletions

diff --git a/build_utils.sh b/build_utils.sh
index cdf7c85..6f02361 100644
--- a/build_utils.sh
+++ b/build_utils.sh
@@ -193,7 +193,11 @@ function create_modules_staging() {
   cp ${src_dir}/modules.builtin ${dest_dir}/modules.builtin
   cp ${src_dir}/modules.builtin.modinfo ${dest_dir}/modules.builtin.modinfo
 
-  if [[ -n "${EXT_MODULES}" ]] || [[ -n "${EXT_MODULES_MAKEFILE}" ]]; then
+  if [[ -n "${KLEAF_MODULES_ORDER}" ]] && [[ -d "${src_dir}/extra" ]]; then
+    mkdir -p ${dest_dir}/extra/
+    cp -r ${src_dir}/extra/* ${dest_dir}/extra/
+    cat ${KLEAF_MODULES_ORDER} >> ${dest_dir}/modules.order
+  elif [[ -n "${EXT_MODULES}" ]] || [[ -n "${EXT_MODULES_MAKEFILE}" ]]; then
     mkdir -p ${dest_dir}/extra/
     cp -r ${src_dir}/extra/* ${dest_dir}/extra/
 
diff --git a/kleaf/impl/common_providers.bzl b/kleaf/impl/common_providers.bzl
index 8dd23e5..994eca5 100644
--- a/kleaf/impl/common_providers.bzl
+++ b/kleaf/impl/common_providers.bzl
@@ -289,6 +289,10 @@ KernelModuleInfo = provider(
             names of all external modules in an unspecified order. This corresponds to `EXT_MODULES`
             in `build.sh`.""",
         "label": "Label to the `kernel_module` target.",
+        "modules_order": """A [depset](https://bazel.build/extending/depsets) of `modules.order`
+            files from ddk_module's, kernel_module, etc.
+            It uses [`postorder`](https://bazel.build/rules/lib/builtins/depset) ordering (dependencies
+            first).""",
     },
 )
 
diff --git a/kleaf/impl/image/image_utils.bzl b/kleaf/impl/image/image_utils.bzl
index c577e9d..3357fa5 100644
--- a/kleaf/impl/image/image_utils.bzl
+++ b/kleaf/impl/image/image_utils.bzl
@@ -164,6 +164,18 @@ def _build_modules_image_impl_common(
             options = "-al --chmod=F+w --include=source --include=build --exclude='*'",
         )
 
+    modules_order_cmd = ""
+    if ctx.attr.create_modules_order:
+        modules_order_depset = ctx.attr.kernel_modules_install[KernelModuleInfo].modules_order
+        modules_order_depset_list = modules_order_depset.to_list()
+        inputs += modules_order_depset_list
+        modules_order_cmd = """
+            cat {modules_order} > kleaf_modules.order
+            KLEAF_MODULES_ORDER=kleaf_modules.order
+        """.format(
+            modules_order = " ".join([modules_order.path for modules_order in modules_order_depset_list]),
+        )
+
     if set_ext_modules and ctx.attr._set_ext_modules[BuildSettingInfo].value:
         ext_modules = ctx.attr.kernel_modules_install[KernelModuleInfo].packages.to_list()
         command += """EXT_MODULES={quoted_ext_modules}""".format(
@@ -181,9 +193,11 @@ file a bug.""")
                mkdir -p ${{DIST_DIR}}
                cp {system_map} ${{DIST_DIR}}/System.map
 
+               {modules_order_cmd}
                {build_command}
     """.format(
         system_map = system_map.path,
+        modules_order_cmd = modules_order_cmd,
         build_command = build_command,
     )
 
@@ -214,6 +228,12 @@ def _build_modules_image_attrs_common(additional = None):
         "_set_ext_modules": attr.label(
             default = "//build/kernel/kleaf:set_ext_modules",
         ),
+        "create_modules_order": attr.bool(
+            default = True,
+            doc = """Whether to create and keep a modules.order file generated
+                by a postorder traversal of the `kernel_modules_install` sources.
+                It defaults to `True`.""",
+        ),
     }
     if additional != None:
         ret.update(additional)
diff --git a/kleaf/impl/image/kernel_images.bzl b/kleaf/impl/image/kernel_images.bzl
index 1d0b4ce..f2b7360 100644
--- a/kleaf/impl/image/kernel_images.bzl
+++ b/kleaf/impl/image/kernel_images.bzl
@@ -66,6 +66,7 @@ def kernel_images(
         avb_boot_algorithm = None,
         avb_boot_partition_name = None,
         dedup_dlkm_modules = None,
+        create_modules_order = None,
         **kwargs):
     """Build multiple kernel images.
 
@@ -302,7 +303,10 @@ def kernel_images(
 
           If set, **additional changes in the userspace is required** so that
           `system_dlkm` modules are loaded before `vendor_dlkm` modules.
-
+        create_modules_order: Whether to create and keep a modules.order file
+          generated by a postorder traversal of the `kernel_modules_install` sources.
+          It applies to building `initramfs` and `vendor_dlkm` where previously
+          `$EXT_MODULES` was used. It defaults to `True`.
         **kwargs: Additional attributes to the internal rule, e.g.
           [`visibility`](https://docs.bazel.build/versions/main/visibility.html).
           See complete list
@@ -386,6 +390,7 @@ def kernel_images(
             modules_options = modules_options,
             ramdisk_compression = ramdisk_compression,
             ramdisk_compression_args = ramdisk_compression_args,
+            create_modules_order = create_modules_order,
             **kwargs
         )
         all_rules.append(":{}_initramfs".format(name))
@@ -406,6 +411,7 @@ def kernel_images(
             system_dlkm_modules_list = system_dlkm_modules_list,
             system_dlkm_modules_blocklist = system_dlkm_modules_blocklist,
             system_dlkm_props = system_dlkm_props,
+            create_modules_order = False,
             **kwargs
         )
         all_rules.append(":{}_system_dlkm_image".format(name))
@@ -428,6 +434,7 @@ def kernel_images(
             dedup_dlkm_modules = dedup_dlkm_modules,
             system_dlkm_image = "{}_system_dlkm_image".format(name) if build_system_dlkm else None,
             base_kernel_images = base_kernel_images,
+            create_modules_order = create_modules_order,
             **kwargs
         )
         all_rules.append(":{}_vendor_dlkm_image".format(name))
diff --git a/kleaf/impl/kernel_module.bzl b/kleaf/impl/kernel_module.bzl
index cbd84df..d24210b 100644
--- a/kleaf/impl/kernel_module.bzl
+++ b/kleaf/impl/kernel_module.bzl
@@ -417,6 +417,18 @@ def _kernel_module_impl(ctx):
     command += modpost_warn.cmd
     command_outputs += modpost_warn.outputs
 
+    # Keep a record of the modules.order generated by `make`.
+    modules_order = ctx.actions.declare_file("{}/modules.order".format(ctx.attr.name))
+    command_outputs.append(modules_order)
+    grab_modules_order_cmd = """
+        # Backup modules.order files before optionally dropping them.
+        cp -L -p {modules_staging_dir}/lib/modules/*/extra/{ext_mod}/modules.order.* {modules_order}
+    """.format(
+        ext_mod = ext_mod,
+        modules_staging_dir = modules_staging_dws.directory.path,
+        modules_order = modules_order.path,
+    )
+
     make_filter = ""
     if not ctx.attr.generate_btf:
         # Filter out warnings if there is no need for BTF generation
@@ -459,7 +471,8 @@ def _kernel_module_impl(ctx):
                {grab_cmd_cmd}
              # Move Module.symvers
                rsync -aL ${{OUT_DIR}}/${{ext_mod_rel}}/Module.symvers {module_symvers}
-
+             # Grab and then drop modules.order
+               {grab_modules_order_cmd}
                {drop_modules_order_cmd}
                """.format(
         label = ctx.label,
@@ -476,6 +489,7 @@ def _kernel_module_impl(ctx):
         all_module_names_file = all_module_names_file.path,
         grab_unstripped_cmd = grab_unstripped_cmd,
         check_no_remaining = check_no_remaining.path,
+        grab_modules_order_cmd = grab_modules_order_cmd,
         drop_modules_order_cmd = drop_modules_order_cmd,
         grab_cmd_cmd = grab_cmd_step.cmd,
     )
@@ -608,6 +622,7 @@ def _kernel_module_impl(ctx):
             files = depset(output_files),
             packages = depset([ext_mod]),
             label = ctx.label,
+            modules_order = depset([modules_order]),
         ),
         KernelUnstrippedModulesInfo(
             directories = depset([unstripped_dir], order = "postorder"),
diff --git a/kleaf/impl/kernel_module_group.bzl b/kleaf/impl/kernel_module_group.bzl
index 28409f7..831ad36 100644
--- a/kleaf/impl/kernel_module_group.bzl
+++ b/kleaf/impl/kernel_module_group.bzl
@@ -65,6 +65,10 @@ def _kernel_module_group_impl(ctx):
         ]),
         packages = depset(transitive = [target[KernelModuleInfo].packages for target in targets]),
         label = ctx.label,
+        modules_order = depset(
+            transitive = [target[KernelModuleInfo].modules_order for target in targets],
+            order = "postorder",
+        ),
     )
 
     unstripped_modules_info = KernelUnstrippedModulesInfo(
diff --git a/kleaf/impl/kernel_modules_install.bzl b/kleaf/impl/kernel_modules_install.bzl
index cb38106..c8ab534 100644
--- a/kleaf/impl/kernel_modules_install.bzl
+++ b/kleaf/impl/kernel_modules_install.bzl
@@ -194,6 +194,10 @@ def _kernel_modules_install_impl(ctx):
                 for target in ctx.attr.kernel_modules
             ]),
             label = ctx.label,
+            modules_order = depset(transitive = [
+                target[KernelModuleInfo].modules_order
+                for target in ctx.attr.kernel_modules
+            ], order = "postorder"),
         ),
         cmds_info,
     ]