uml: initial revision

Added AndroidProducts.mk, which tells the build system to find the uml
makefile at uml.mk.

BoardConfig.mk specifies system.img to consist only of the /system
partition instead of the root. With CONFIG_BLK_DEV_INITRD=y in the
kernel, it is possible to boot from ramdisk.img and mount /data and
/system during init. TARGET_USER_MODE_LINUX enables uml-specific cflags.
TARGET_USES_64_BIT_BINDER is set to true due to UML not supporting
running 32-bit binaries in 64-bit mode.

Added fstab.uml to mount /data, /system, and the host filesystem
as a partition named /host. Since adb does not work with uml yet, an
already mounted hostfs makes it convenient to transfer files to the
uml system.

Added init.uml.rc, which tells init to mount the contents of fstab.uml
during the fs stage.

Added basic uml.mk to inherit minimal packages from embedded.mk and
copy init.uml.rc, fstab.uml, and surfaceflinger.rc into the system.img.

Failing service surfaceflinger has been disabled by the inclusion of a
custom surfaceflinger.rc file, which simply has `disabled' appended to
it.

Added vendorsetup.sh to add lunch combo uml-userdebug

In order to run UML for Android, you must have built the um kernel
with Android configs. To do this, run these commands from the kernel
repository:

$ ARCH=um SUBARCH=x86_64 scripts/kconfig/merge_config.sh
arch/um/configs/x86_64_defconfig kernel/configs/android-base.config
kernel/configs/android-recommended.config
$ make ARCH=um SUBARCH=x86_64 CROSS_COMPILE= -j40

The output is an executable vmlinux binary.

The command to run UML is:
$ ./vmlinux initrd=ramdisk.img ubda=system.img ubdb=userdata.img
androidboot.hardware=uml mem=256M umid=<umid>

To halt the uml process, in another terminal, run `uml_mconsole <umid>'
and supply the command `halt'.

Test: manual

Bug: 32523022
Change-Id: I4a1cd6ceb42831a995bbefd3dd8a6ca3596d65ea
Signed-off-by: Quang Luong <qal@google.com>

7 files changed, 92 insertions, 0 deletions

diff --git a/AndroidProducts.mk b/AndroidProducts.mk
new file mode 100644
index 0000000..369b2d4
--- /dev/null
+++ b/AndroidProducts.mk
@@ -0,0 +1,18 @@
+#
+# Copyright (C) 2017 The Android Open-Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+PRODUCT_MAKEFILES := \
+    $(LOCAL_DIR)/uml.mk
\ No newline at end of file
diff --git a/BoardConfig.mk b/BoardConfig.mk
new file mode 100644
index 0000000..b6eb431
--- /dev/null
+++ b/BoardConfig.mk
@@ -0,0 +1,22 @@
+#
+# Product-specific compile-time definitions.
+#
+
+# The generic product target doesn't have any hardware-specific pieces.
+TARGET_NO_BOOTLOADER := true
+TARGET_NO_KERNEL := true
+TARGET_CPU_ABI := x86_64
+TARGET_ARCH := x86_64
+TARGET_ARCH_VARIANT := x86_64
+
+TARGET_USER_MODE_LINUX := true
+
+TARGET_USES_64_BIT_BINDER := true
+
+TARGET_USERIMAGES_USE_EXT4 := true
+# Let UML mount userdata.img in a non-sparse format
+TARGET_USERIMAGES_SPARSE_EXT_DISABLED := true
+
+BOARD_SYSTEMIMAGE_PARTITION_SIZE := 786432000
+BOARD_USERDATAIMAGE_PARTITION_SIZE := 576716800
+BOARD_FLASH_BLOCK_SIZE := 512
diff --git a/fstab.uml b/fstab.uml
new file mode 100644
index 0000000..1131f38
--- /dev/null
+++ b/fstab.uml
@@ -0,0 +1,8 @@
+# Android fstab file.
+#<src>                                                  <mnt_point>         <type>    <mnt_flags and options>                              <fs_mgr_flags>
+# The filesystem that contains the filesystem checker binary (typically /system) cannot
+# specify MF_CHECK, and must come before any filesystems that do specify MF_CHECK
+/dev/block/ubda                                         /system             ext4      ro                                                   wait
+/dev/block/ubdb                                         /data               ext4      noatime,nosuid,nodev,nomblk_io_submit,errors=panic   wait,check
+# When UML sees type "hostfs", it will mount the hostfs to the mount point instead of checking the <src>
+none                                                    /host               hostfs    defaults                                             none
diff --git a/init.uml.rc b/init.uml.rc
new file mode 100644
index 0000000..e5b5d7d
--- /dev/null
+++ b/init.uml.rc
@@ -0,0 +1,2 @@
+on fs
+    mount_all ./fstab.uml
diff --git a/surfaceflinger.rc b/surfaceflinger.rc
new file mode 100644
index 0000000..0f2cb32
--- /dev/null
+++ b/surfaceflinger.rc
@@ -0,0 +1,12 @@
+# This custom surfaceflinger.rc simply has `disabled' appended to it.
+# Since we are using UML without a screen, and embedded.mk is the
+# smallest mk file but still contains surfaceflinger, including this
+# custom surfaceflinger.rc will disable surfaceflinger from running.
+
+service surfaceflinger /system/bin/surfaceflinger
+    class core
+    user system
+    group graphics drmrpc readproc
+    onrestart restart zygote
+    writepid /dev/stune/foreground/tasks
+    disabled
diff --git a/uml.mk b/uml.mk
new file mode 100644
index 0000000..a7fa7f7
--- /dev/null
+++ b/uml.mk
@@ -0,0 +1,29 @@
+# Copyright (C) 2017 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+$(call inherit-product, $(SRC_TARGET_DIR)/product/core_64_bit.mk)
+$(call inherit-product, $(SRC_TARGET_DIR)/product/embedded.mk)
+
+PRODUCT_NAME := uml
+PRODUCT_DEVICE := uml
+PRODUCT_BRAND := Android
+PRODUCT_MODEL := UML for x86_64
+
+# default is nosdcard, S/W button enabled in resource
+DEVICE_PACKAGE_OVERLAYS := device/generic/x86/overlay
+PRODUCT_CHARACTERISTICS := nosdcard
+
+PRODUCT_COPY_FILES += $(LOCAL_PATH)/fstab.uml:root/fstab.uml
+PRODUCT_COPY_FILES += $(LOCAL_PATH)/init.uml.rc:root/init.uml.rc
+PRODUCT_COPY_FILES += $(LOCAL_PATH)/surfaceflinger.rc:system/etc/init/surfaceflinger.rc
diff --git a/vendorsetup.sh b/vendorsetup.sh
new file mode 100755
index 0000000..fd5fc0b
--- /dev/null
+++ b/vendorsetup.sh
@@ -0,0 +1 @@
+add_lunch_combo uml-userdebug