m/n/b/unifiedefi: add bazel rule for EFI unified kernel images
This adds a new Bazel rule for generating EFI unified kernel images.
It also wraps the current Metropolis kernel in one for future use
and as a cheap test.
Change-Id: I74d7a25cc3c12d5f240eb218fbbd8ba09db1333a
Reviewed-on: https://review.monogon.dev/c/monogon/+/336
Reviewed-by: Sergiusz Bazanski <serge@monogon.tech>
diff --git a/metropolis/node/BUILD.bazel b/metropolis/node/BUILD.bazel
index feade24..db01806 100644
--- a/metropolis/node/BUILD.bazel
+++ b/metropolis/node/BUILD.bazel
@@ -1,5 +1,6 @@
load("@io_bazel_rules_go//go:def.bzl", "go_library")
load("//metropolis/node/build:def.bzl", "erofs_image")
+load("//metropolis/node/build:efi.bzl", "efi_unified_kernel_image")
go_library(
name = "go_default_library",
@@ -89,10 +90,16 @@
},
)
+efi_unified_kernel_image(
+ name = "kernel_efi",
+ kernel = "//third_party/linux",
+ os_release = ":os-release-info",
+)
+
genrule(
name = "image",
srcs = [
- "//third_party/linux",
+ ":kernel_efi",
":rootfs",
],
outs = [
@@ -100,7 +107,7 @@
],
cmd = """
$(location //metropolis/node/build/mkimage) \
- -efi $(location //third_party/linux) \
+ -efi $(location :kernel_efi) \
-system $(location :rootfs) \
-out $@
""",
diff --git a/metropolis/node/build/efi.bzl b/metropolis/node/build/efi.bzl
new file mode 100644
index 0000000..21b1ef9
--- /dev/null
+++ b/metropolis/node/build/efi.bzl
@@ -0,0 +1,95 @@
+"""Rules for generating EFI unified kernel images. These are EFI-bootable PE/COFF files containing a stub loader,
+a kernel, and optional commandline and initramfs in one file.
+See https://systemd.io/BOOT_LOADER_SPECIFICATION/#type-2-efi-unified-kernel-images for more information.
+"""
+
+load("//build/toolchain/llvm-efi:transition.bzl", "build_efi_transition")
+
+def _efi_unified_kernel_image_impl(ctx):
+ out = ctx.actions.declare_file(ctx.attr.name + ".efi")
+
+ toolchain_info = ctx.attr._toolchain[platform_common.ToolchainInfo]
+
+ sections = [
+ dict(name = ".linux", file = ctx.file.kernel, vma = 0x2000000),
+ ]
+
+ if ctx.attr.cmdline != "":
+ cmdline_file = ctx.actions.declare_file("cmdline")
+ ctx.actions.write(
+ output = cmdline_file,
+ content = ctx.attr.cmdline,
+ )
+ sections.append(dict(name = ".cmdline", file = cmdline_file, vma = 0x30000))
+
+ if ctx.file.initramfs:
+ sections += [dict(name = ".initrd", file = ctx.file.initramfs, vma = 0x5000000)]
+ if ctx.file.os_release:
+ sections += [dict(name = ".osrel", file = ctx.file.os_release, vma = 0x20000)]
+ if ctx.file.splash:
+ sections += [dict(name = ".splash", file = ctx.file.splash, vma = 0x40000)]
+
+ args = []
+ for sec in sections:
+ args.append("--add-section")
+ args.append("{}={}".format(sec["name"], sec["file"].path))
+ args.append("--change-section-vma")
+ args.append("{}={}".format(sec["name"], sec["vma"]))
+
+ ctx.actions.run(
+ mnemonic = "GenEFIKernelImage",
+ progress_message = "Generating EFI unified kernel image",
+ inputs = [ctx.file.stub] + [s["file"] for s in sections],
+ outputs = [out],
+ executable = toolchain_info.objcopy_executable,
+ arguments = args + [
+ ctx.file.stub.path,
+ out.path,
+ ],
+ )
+ return [DefaultInfo(files = depset([out]), runfiles = ctx.runfiles(files = [out]))]
+
+efi_unified_kernel_image = rule(
+ implementation = _efi_unified_kernel_image_impl,
+ attrs = {
+ "kernel": attr.label(
+ doc = "The Linux kernel executable bzImage. Needs to have EFI handover and EFI stub enabled.",
+ mandatory = True,
+ allow_single_file = True,
+ ),
+ "cmdline": attr.string(
+ doc = "The kernel commandline to be embedded.",
+ ),
+ "initramfs": attr.label(
+ doc = "The initramfs to be embedded.",
+ allow_single_file = True,
+ ),
+ "os_release": attr.label(
+ doc = """
+ The os-release file identifying the operating system.
+ See https://www.freedesktop.org/software/systemd/man/os-release.html for format.
+ """,
+ allow_single_file = True,
+ ),
+ "splash": attr.label(
+ doc = "An image in BMP format which will be displayed as a splash screen until the kernel takes over.",
+ allow_single_file = True,
+ ),
+ "stub": attr.label(
+ doc = "The stub executable itself as a PE/COFF executable.",
+ default = "@efistub//:efistub",
+ allow_single_file = True,
+ executable = True,
+ cfg = build_efi_transition,
+ ),
+ "_toolchain": attr.label(
+ doc = "The toolchain used for objcopy.",
+ default = "//build/toolchain/llvm-efi:efi_cc_suite",
+ providers = [platform_common.ToolchainInfo],
+ ),
+ # Allow for transitions to be attached to this rule.
+ "_whitelist_function_transition": attr.label(
+ default = "@bazel_tools//tools/whitelists/function_transition_whitelist",
+ ),
+ },
+)