Remove deprecated BOARD_BUILD_SYSTEM_ROOT_IMAGE

This variable is always false or empty now, so clean up remaining
references of the variable.

Remove "buildvariant=" kernel commandline as it was used by
system-as-root kernels to determine the system build variant. It is
unsupported now.

Bug: 241346584
Test: Presubmit
Change-Id: I0f97b6e0bf8b03429f65366119ff78f9c7983516
diff --git a/core/Makefile b/core/Makefile
index 198beb1..5afdfa7 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -975,10 +975,8 @@
 
 # TODO(b/229701033): clean up BOARD_BUILD_GKI_BOOT_IMAGE_WITHOUT_RAMDISK.
 ifneq ($(BOARD_BUILD_GKI_BOOT_IMAGE_WITHOUT_RAMDISK),true)
-  ifneq ($(BOARD_BUILD_SYSTEM_ROOT_IMAGE),true)
-    ifneq ($(BUILDING_INIT_BOOT_IMAGE),true)
-      INTERNAL_BOOTIMAGE_ARGS += --ramdisk $(INSTALLED_RAMDISK_TARGET)
-    endif
+  ifneq ($(BUILDING_INIT_BOOT_IMAGE),true)
+    INTERNAL_BOOTIMAGE_ARGS += --ramdisk $(INSTALLED_RAMDISK_TARGET)
   endif
 endif
 
@@ -990,9 +988,6 @@
 
 INTERNAL_BOOTIMAGE_FILES := $(filter-out --%,$(INTERNAL_BOOTIMAGE_ARGS))
 
-# TODO(b/241346584) Remove this when BOARD_BUILD_SYSTEM_ROOT_IMAGE is deprecated
-INTERNAL_KERNEL_CMDLINE := $(strip $(INTERNAL_KERNEL_CMDLINE) buildvariant=$(TARGET_BUILD_VARIANT))
-
 # kernel cmdline/base/pagesize in boot.
 # - If using GKI, use GENERIC_KERNEL_CMDLINE. Remove kernel base and pagesize because they are
 #   device-specific.
@@ -1989,8 +1984,6 @@
         $(hide) echo "avb_system_dlkm_rollback_index_location=$(BOARD_SYSTEM_SYSTEM_DLKM_ROLLBACK_INDEX_LOCATION)" >> $(1)))
 $(if $(filter true,$(BOARD_USES_RECOVERY_AS_BOOT)),\
     $(hide) echo "recovery_as_boot=true" >> $(1))
-$(if $(filter true,$(BOARD_BUILD_SYSTEM_ROOT_IMAGE)),\
-    $(hide) echo "system_root_image=true" >> $(1))
 $(if $(filter true,$(BOARD_BUILD_GKI_BOOT_IMAGE_WITHOUT_RAMDISK)),\
     $(hide) echo "gki_boot_image_without_ramdisk=true" >> $(1))
 $(hide) echo "root_dir=$(TARGET_ROOT_OUT)" >> $(1)
@@ -2267,20 +2260,18 @@
 #      (BOARD_USES_FULL_RECOVERY_IMAGE = true);
 #   b) We build a single image that contains boot and recovery both - no recovery image to install
 #      (BOARD_USES_RECOVERY_AS_BOOT = true);
-#   c) We mount the system image as / and therefore do not have a ramdisk in boot.img
-#      (BOARD_BUILD_SYSTEM_ROOT_IMAGE = true).
-#   d) We include the recovery DTBO image within recovery - not needing the resource file as we
+#   c) We include the recovery DTBO image within recovery - not needing the resource file as we
 #      do bsdiff because boot and recovery will contain different number of entries
 #      (BOARD_INCLUDE_RECOVERY_DTBO = true).
-#   e) We include the recovery ACPIO image within recovery - not needing the resource file as we
+#   d) We include the recovery ACPIO image within recovery - not needing the resource file as we
 #      do bsdiff because boot and recovery will contain different number of entries
 #      (BOARD_INCLUDE_RECOVERY_ACPIO = true).
-#   f) We build a single image that contains vendor_boot and recovery both - no recovery image to
+#   e) We build a single image that contains vendor_boot and recovery both - no recovery image to
 #      install
 #      (BOARD_MOVE_RECOVERY_RESOURCES_TO_VENDOR_BOOT = true).
 
 ifeq (,$(filter true, $(BOARD_USES_FULL_RECOVERY_IMAGE) $(BOARD_USES_RECOVERY_AS_BOOT) \
-  $(BOARD_BUILD_SYSTEM_ROOT_IMAGE) $(BOARD_INCLUDE_RECOVERY_DTBO) $(BOARD_INCLUDE_RECOVERY_ACPIO) \
+  $(BOARD_INCLUDE_RECOVERY_DTBO) $(BOARD_INCLUDE_RECOVERY_ACPIO) \
   $(BOARD_MOVE_RECOVERY_RESOURCES_TO_VENDOR_BOOT)))
 # Named '.dat' so we don't attempt to use imgdiff for patching it.
 RECOVERY_RESOURCE_ZIP := $(TARGET_OUT_VENDOR)/etc/recovery-resource.dat
@@ -2402,8 +2393,7 @@
 	# Use rsync because "cp -Rf" fails to overwrite broken symlinks on Mac.
 	rsync -a --exclude=sdcard $(IGNORE_RECOVERY_SEPOLICY) $(IGNORE_CACHE_LINK) $(TARGET_ROOT_OUT) $(TARGET_RECOVERY_OUT)
 	# Modifying ramdisk contents...
-	$(if $(filter true,$(BOARD_BUILD_SYSTEM_ROOT_IMAGE)),, \
-	  ln -sf /system/bin/init $(TARGET_RECOVERY_ROOT_OUT)/init)
+	ln -sf /system/bin/init $(TARGET_RECOVERY_ROOT_OUT)/init
 	# Removes $(TARGET_RECOVERY_ROOT_OUT)/init*.rc EXCEPT init.recovery*.rc.
 	find $(TARGET_RECOVERY_ROOT_OUT) -maxdepth 1 -name 'init*.rc' -type f -not -name "init.recovery.*.rc" | xargs rm -f
 	cp $(TARGET_ROOT_OUT)/init.recovery.*.rc $(TARGET_RECOVERY_ROOT_OUT)/ 2> /dev/null || true # Ignore error when the src file doesn't exist.
@@ -3156,7 +3146,7 @@
 ifneq ($(INSTALLED_BOOTIMAGE_TARGET),)
 ifneq ($(INSTALLED_RECOVERYIMAGE_TARGET),)
 ifneq ($(BOARD_USES_FULL_RECOVERY_IMAGE),true)
-ifneq (,$(filter true, $(BOARD_BUILD_SYSTEM_ROOT_IMAGE) $(BOARD_INCLUDE_RECOVERY_DTBO) $(BOARD_INCLUDE_RECOVERY_ACPIO)))
+ifneq (,$(filter true,$(BOARD_INCLUDE_RECOVERY_DTBO) $(BOARD_INCLUDE_RECOVERY_ACPIO)))
 diff_tool := $(HOST_OUT_EXECUTABLES)/bsdiff
 else
 diff_tool := $(HOST_OUT_EXECUTABLES)/imgdiff
@@ -4357,18 +4347,6 @@
     $(eval $(call check-and-set-custom-avb-chain-args,$(partition))))
 endif
 
-# Add kernel cmdline descriptor for kernel to mount system.img as root with
-# dm-verity. This works when system.img is either chained or not-chained:
-# - chained: The --setup_as_rootfs_from_kernel option will add dm-verity kernel
-#   cmdline descriptor to system.img
-# - not-chained: The --include_descriptors_from_image option for make_vbmeta_image
-#   will include the kernel cmdline descriptor from system.img into vbmeta.img
-ifeq ($(BOARD_BUILD_SYSTEM_ROOT_IMAGE),true)
-ifeq ($(filter system, $(BOARD_SUPER_PARTITION_PARTITION_LIST)),)
-BOARD_AVB_SYSTEM_ADD_HASHTREE_FOOTER_ARGS += --setup_as_rootfs_from_kernel
-endif
-endif
-
 BOARD_AVB_MAKE_VBMETA_IMAGE_ARGS += --padding_size 4096
 BOARD_AVB_MAKE_VBMETA_SYSTEM_IMAGE_ARGS += --padding_size 4096
 BOARD_AVB_MAKE_VBMETA_VENDOR_IMAGE_ARGS += --padding_size 4096
@@ -5703,10 +5681,8 @@
 	    $(TARGET_ROOT_OUT),$(zip_root)/ROOT)
 	@# If we are using recovery as boot, this is already done when processing recovery.
 ifneq ($(BOARD_USES_RECOVERY_AS_BOOT),true)
-ifneq ($(BOARD_BUILD_SYSTEM_ROOT_IMAGE),true)
 	$(hide) $(call package_files-copy-root, \
 	    $(TARGET_RAMDISK_OUT),$(zip_root)/BOOT/RAMDISK)
-endif
 ifdef INSTALLED_KERNEL_TARGET
 	$(hide) cp $(INSTALLED_KERNEL_TARGET) $(zip_root)/BOOT/
 endif
@@ -6012,10 +5988,8 @@
 endif
 	@# ROOT always contains the files for the root under normal boot.
 	$(hide) $(call fs_config,$(zip_root)/ROOT,) > $(zip_root)/META/root_filesystem_config.txt
-ifeq ($(BOARD_USES_RECOVERY_AS_BOOT),true)
-	@# BOOT/RAMDISK exists and contains the ramdisk for recovery if using BOARD_USES_RECOVERY_AS_BOOT.
+	@# BOOT/RAMDISK contains the first stage and recovery ramdisk.
 	$(hide) $(call fs_config,$(zip_root)/BOOT/RAMDISK,) > $(zip_root)/META/boot_filesystem_config.txt
-endif
 ifdef BUILDING_INIT_BOOT_IMAGE
 	$(hide) $(call package_files-copy-root, $(TARGET_RAMDISK_OUT),$(zip_root)/INIT_BOOT/RAMDISK)
 	$(hide) $(call fs_config,$(zip_root)/INIT_BOOT/RAMDISK,) > $(zip_root)/META/init_boot_filesystem_config.txt
@@ -6026,10 +6000,6 @@
 ifneq ($(INSTALLED_VENDOR_BOOTIMAGE_TARGET),)
 	$(call fs_config,$(zip_root)/VENDOR_BOOT/RAMDISK,) > $(zip_root)/META/vendor_boot_filesystem_config.txt
 endif
-ifneq ($(BOARD_BUILD_SYSTEM_ROOT_IMAGE),true)
-	@# BOOT/RAMDISK also exists and contains the first stage ramdisk if not using BOARD_BUILD_SYSTEM_ROOT_IMAGE.
-	$(hide) $(call fs_config,$(zip_root)/BOOT/RAMDISK,) > $(zip_root)/META/boot_filesystem_config.txt
-endif
 ifneq ($(INSTALLED_RECOVERYIMAGE_TARGET),)
 	$(hide) $(call fs_config,$(zip_root)/RECOVERY/RAMDISK,) > $(zip_root)/META/recovery_filesystem_config.txt
 endif