Make `runDepmod` behave more like `build-image-kernel-modules`

This CL adds the following to `prebuilt_kernel_modules`
1. System_deps property. This will be copied to the intermediates
   directory for running depmod, but will not be installed as part of
   this module. The use case for this is vendor_dlkm which depends on
   system_dlkm
2. Copy .ko files to staging directory based on their final install
   location on device.

More details on (2):
At ToT, the .ko files are copied to
$intermediates/lib/modules/0.0/*.ko

The resulting modules.dep is
foo.ko: bar.ko baz.ko

However, android devices do not have a single dlkm partition,
/lib/modules/, but we have split dlkm partitions. To ensure that the
modules.dep file resembles the paths on device, the .ko files will be
copied to the the following

$intermediates/lib/modules/0.0/system/lib/modules/*.ko
$intermediates/lib/modules/0.0/vendor/lib/modules/*.ko
$intermediates/lib/modules/0.0/odm/lib/modules/*.ko

The resulting modules.dep is
/vendor/lib/modules/foo.ko: /vendor/lib/modules/bar.ko
/system/modules/lib/baz.ko

Bug: 377562851
Test: verified that modules.* files are bit-identical for system_dlkm,
vendor_dlkm, odm_dlkm between kati and soong for aosp CF (top of CL
stack)

Change-Id: I000b45dcba041b03d86fb971d45b54147250148e

1 files changed, 63 insertions, 4 deletions

diff --git a/kernel/prebuilt_kernel_modules.go b/kernel/prebuilt_kernel_modules.go
index 5893211fb..78a463f75 100644
--- a/kernel/prebuilt_kernel_modules.go
+++ b/kernel/prebuilt_kernel_modules.go
@@ -47,6 +47,11 @@ type prebuiltKernelModulesProperties struct {
 	// List or filegroup of prebuilt kernel module files. Should have .ko suffix.
 	Srcs []string `android:"path,arch_variant"`
 
+	// List of system_dlkm kernel modules that the local kernel modules depend on.
+	// The deps will be assembled into intermediates directory for running depmod
+	// but will not be added to the current module's installed files.
+	System_deps []string `android:"path,arch_variant"`
+
 	// If false, then srcs will not be included in modules.load.
 	// This feature is used by system_dlkm
 	Load_by_default *bool
@@ -85,7 +90,9 @@ func (pkm *prebuiltKernelModules) GenerateAndroidBuildActions(ctx android.Module
 	if !pkm.installable() {
 		pkm.SkipInstall()
 	}
+
 	modules := android.PathsForModuleSrc(ctx, pkm.properties.Srcs)
+	systemModules := android.PathsForModuleSrc(ctx, pkm.properties.System_deps)
 
 	depmodOut := pkm.runDepmod(ctx, modules, systemModules)
 	strippedModules := stripDebugSymbols(ctx, modules)
@@ -102,6 +109,8 @@ func (pkm *prebuiltKernelModules) GenerateAndroidBuildActions(ctx android.Module
 	ctx.InstallFile(installDir, "modules.dep", depmodOut.modulesDep)
 	ctx.InstallFile(installDir, "modules.softdep", depmodOut.modulesSoftdep)
 	ctx.InstallFile(installDir, "modules.alias", depmodOut.modulesAlias)
+
+	ctx.SetOutputFiles(modules, ".modules")
 }
 
 var (
@@ -141,18 +150,56 @@ type depmodOutputs struct {
 	modulesAlias   android.OutputPath
 }
 
+var (
+	// system/lib/modules/foo.ko: system/lib/modules/bar.ko
+	// will be converted to
+	// /system/lib/modules/foo.ko: /system/lib/modules/bar.ko
+	addLeadingSlashToPaths = pctx.AndroidStaticRule("add_leading_slash",
+		blueprint.RuleParams{
+			Command: `sed -e 's|\([^: ]*lib/modules/[^: ]*\)|/\1|g' $in > $out`,
+		},
+	)
+)
+
+// This is the path in soong intermediates where the .ko files will be copied.
+// The layout should match the layout on device so that depmod can create meaningful modules.* files.
+func modulesDirForAndroidDlkm(ctx android.ModuleContext, modulesDir android.OutputPath, system bool) android.OutputPath {
+	if ctx.InstallInSystemDlkm() || system {
+		// The first component can be either system or system_dlkm
+		// system works because /system/lib/modules is a symlink to /system_dlkm/lib/modules.
+		// system was chosen to match the contents of the kati built modules.dep
+		return modulesDir.Join(ctx, "system", "lib", "modules")
+	} else if ctx.InstallInVendorDlkm() {
+		return modulesDir.Join(ctx, "vendor", "lib", "modules")
+	} else if ctx.InstallInOdmDlkm() {
+		return modulesDir.Join(ctx, "odm", "lib", "modules")
+	} else {
+		// not an android dlkm module.
+		return modulesDir
+	}
+}
+
 func (pkm *prebuiltKernelModules) runDepmod(ctx android.ModuleContext, modules android.Paths, systemModules android.Paths) depmodOutputs {
 	baseDir := android.PathForModuleOut(ctx, "depmod").OutputPath
 	fakeVer := "0.0" // depmod demands this anyway
 	modulesDir := baseDir.Join(ctx, "lib", "modules", fakeVer)
+	modulesCpDir := modulesDirForAndroidDlkm(ctx, modulesDir, false)
 
 	builder := android.NewRuleBuilder(pctx, ctx)
 
 	// Copy the module files to a temporary dir
-	builder.Command().Text("rm").Flag("-rf").Text(modulesDir.String())
-	builder.Command().Text("mkdir").Flag("-p").Text(modulesDir.String())
+	builder.Command().Text("rm").Flag("-rf").Text(modulesCpDir.String())
+	builder.Command().Text("mkdir").Flag("-p").Text(modulesCpDir.String())
 	for _, m := range modules {
-		builder.Command().Text("cp").Input(m).Text(modulesDir.String())
+		builder.Command().Text("cp").Input(m).Text(modulesCpDir.String())
+	}
+
+	modulesDirForSystemDlkm := modulesDirForAndroidDlkm(ctx, modulesDir, true)
+	if len(systemModules) > 0 {
+		builder.Command().Text("mkdir").Flag("-p").Text(modulesDirForSystemDlkm.String())
+	}
+	for _, m := range systemModules {
+		builder.Command().Text("cp").Input(m).Text(modulesDirForSystemDlkm.String())
 	}
 
 	// Enumerate modules to load
@@ -176,6 +223,7 @@ func (pkm *prebuiltKernelModules) runDepmod(ctx android.ModuleContext, modules a
 	modulesDep := modulesDir.Join(ctx, "modules.dep")
 	modulesSoftdep := modulesDir.Join(ctx, "modules.softdep")
 	modulesAlias := modulesDir.Join(ctx, "modules.alias")
+	builder.Command().Text("mkdir").Flag("-p").Text(modulesDir.String())
 	builder.Command().
 		BuiltTool("depmod").
 		FlagWithArg("-b ", baseDir.String()).
@@ -186,5 +234,16 @@ func (pkm *prebuiltKernelModules) runDepmod(ctx android.ModuleContext, modules a
 
 	builder.Build("depmod", fmt.Sprintf("depmod %s", ctx.ModuleName()))
 
-	return depmodOutputs{modulesLoad, modulesDep, modulesSoftdep, modulesAlias}
+	finalModulesDep := modulesDep
+	// Add a leading slash to paths in modules.dep of android dlkm
+	if ctx.InstallInSystemDlkm() || ctx.InstallInVendorDlkm() || ctx.InstallInOdmDlkm() {
+		finalModulesDep := modulesDep.ReplaceExtension(ctx, "intermediates")
+		ctx.Build(pctx, android.BuildParams{
+			Rule:   addLeadingSlashToPaths,
+			Input:  modulesDep,
+			Output: finalModulesDep,
+		})
+	}
+
+	return depmodOutputs{modulesLoad, finalModulesDep, modulesSoftdep, modulesAlias}
 }