diff --git a/Changes.md b/Changes.md
index 1ab005f..5edb1d8 100644
--- a/Changes.md
+++ b/Changes.md
@@ -1,5 +1,35 @@
 # Build System Changes for Android.mk Writers
 
+## Genrule starts disallowing directory inputs
+
+To better specify the inputs to the build, we are restricting use of directories
+as inputs to genrules.
+
+To fix existing uses, change inputs to specify the inputs and update the command
+accordingly. For example:
+
+```
+genrule: {
+    name: "foo",
+    srcs: ["bar"],
+    cmd: "cp $(location bar)/*.xml $(gendir)",
+    ...
+}
+```
+
+would become
+
+```
+genrule: {
+    name: "foo",
+    srcs: ["bar/*.xml"],
+    cmd: "cp $(in) $(gendir)",
+    ...
+}
+
+`BUILD_BROKEN_INPUT_DIR_MODULES` can be used to allowlist specific directories
+with genrules that have input directories.
+
 ## Dexpreopt starts enforcing `<uses-library>` checks (for Java modules)
 
 In order to construct correct class loader context for dexpreopt, build system
diff --git a/core/board_config.mk b/core/board_config.mk
index 405fea6..97b258d 100644
--- a/core/board_config.mk
+++ b/core/board_config.mk
@@ -174,6 +174,7 @@
   BUILD_BROKEN_DUP_SYSPROP \
   BUILD_BROKEN_ELF_PREBUILT_PRODUCT_COPY_FILES \
   BUILD_BROKEN_ENFORCE_SYSPROP_OWNER \
+  BUILD_BROKEN_INPUT_DIR_MODULES \
   BUILD_BROKEN_MISSING_REQUIRED_MODULES \
   BUILD_BROKEN_OUTSIDE_INCLUDE_DIRS \
   BUILD_BROKEN_PREBUILT_ELF_FILES \
diff --git a/core/soong_config.mk b/core/soong_config.mk
index 355cd3e..c24df60 100644
--- a/core/soong_config.mk
+++ b/core/soong_config.mk
@@ -270,6 +270,7 @@
 $(call add_json_bool, BuildBrokenEnforceSyspropOwner,     $(filter true,$(BUILD_BROKEN_ENFORCE_SYSPROP_OWNER)))
 $(call add_json_bool, BuildBrokenTrebleSyspropNeverallow, $(filter true,$(BUILD_BROKEN_TREBLE_SYSPROP_NEVERALLOW)))
 $(call add_json_bool, BuildBrokenVendorPropertyNamespace, $(filter true,$(BUILD_BROKEN_VENDOR_PROPERTY_NAMESPACE)))
+$(call add_json_list, BuildBrokenInputDirModules, $(BUILD_BROKEN_INPUT_DIR_MODULES))
 
 $(call add_json_bool, BuildDebugfsRestrictionsEnabled, $(filter true,$(PRODUCT_SET_DEBUGFS_RESTRICTIONS)))