[arm] Refactor installer and build to allow arm builds targeted at grub platforms (sonic-net#11341)

Refactors the SONiC Installer to support greater flexibility in building for a given architecture and bootloader. 

#### Why I did it

Currently the SONiC installer assumes that if a platform is ARM based that it uses the `uboot` bootloader and uses the `grub` bootloader otherwise. This is not a correct assumption to make as ARM is not strictly tied to uboot and x86 is not strictly tied to grub. 

#### How I did it

To implement this I introduce the following changes:
* Remove the different arch folders from the `installer/` directory
* Merge the generic components of the ARM and x86 installer into `installer/installer.sh`
* Refactor x86 + grub specific functions into `installer/default_platform.conf` 
* Modify installer to call `default_platform.conf` file and also call `platform/[platform]/patform.conf` file as well to override as needed
* Update references to the installer in the `build_image.sh` script
* Add `TARGET_BOOTLOADER` variable that is by default `uboot` for ARM devices and `grub` for x86 unless overridden in `platform/[platform]/rules.mk`
* Update bootloader logic in `build_debian.sh` to be based on `TARGET_BOOTLOADER` instead of `TARGET_ARCH` and to reference the grub package in a generic manner

#### How to verify it

This has been tested on a ARM test platform as well as on Mellanox amd64 switches as well to ensure there was no impact. 

#### Description for the changelog
[arm] Refactor installer and build to allow arm builds targeted at grub platforms

#### Link to config_db schema for YANG module changes

N/A

Author: alexrallen

Makefile.work

@@ -104,6 +104,12 @@ ifeq ($(PLATFORM_ARCH),)
 	override PLATFORM_ARCH = $(CONFIGURED_ARCH)
 endif
 
+ifeq ($(CONFIGURED_ARCH),amd64)
+TARGET_BOOTLOADER = grub
+else
+TARGET_BOOTLOADER = uboot
+endif
+
 ifeq ($(BLDENV), bullseye)
 SLAVE_DIR = sonic-slave-bullseye
 else ifeq ($(BLDENV), buster)

build_debian.sh

@@ -65,7 +65,7 @@ if [[ -d $FILESYSTEM_ROOT ]]; then
 fi
 mkdir -p $FILESYSTEM_ROOT
 mkdir -p $FILESYSTEM_ROOT/$PLATFORM_DIR
-mkdir -p $FILESYSTEM_ROOT/$PLATFORM_DIR/x86_64-grub
+mkdir -p $FILESYSTEM_ROOT/$PLATFORM_DIR/grub
 touch $FILESYSTEM_ROOT/$PLATFORM_DIR/firsttime
 
 ## ensure proc is mounted
@@ -162,7 +162,7 @@ if [ "$SONIC_ENABLE_SECUREBOOT_SIGNATURE" = "y" ]; then
     fi
 
     echo '[INFO] Signing SONiC linux kernel image'
-    K=$FILESYSTEM_ROOT/boot/vmlinuz-${LINUX_KERNEL_VERSION}-amd64
+    K=$FILESYSTEM_ROOT/boot/vmlinuz-${LINUX_KERNEL_VERSION}-${CONFIGURED_ARCH}
     sbsign --key $SIGNING_KEY --cert $SIGNING_CERT --output /tmp/${K##*/} ${K}
     sudo cp -f /tmp/${K##*/} ${K}
 fi
@@ -392,11 +392,17 @@ sudo LANG=C DEBIAN_FRONTEND=noninteractive chroot $FILESYSTEM_ROOT apt-get -y in
     systemd-sysv \
     ntp
 
-if [[ $CONFIGURED_ARCH == amd64 ]]; then
+if [[ $TARGET_BOOTLOADER == grub ]]; then
+    if [[ $CONFIGURED_ARCH == amd64 ]]; then
+        GRUB_PKG=grub-pc-bin
+    elif [[ $CONFIGURED_ARCH == arm64 ]]; then
+        GRUB_PKG=grub-efi-arm64-bin
+    fi
+
     sudo LANG=C DEBIAN_FRONTEND=noninteractive chroot $FILESYSTEM_ROOT apt-get -y download \
-        grub-pc-bin
+        $GRUB_PKG
 
-    sudo mv $FILESYSTEM_ROOT/grub-pc-bin*.deb $FILESYSTEM_ROOT/$PLATFORM_DIR/x86_64-grub
+    sudo mv $FILESYSTEM_ROOT/grub*.deb $FILESYSTEM_ROOT/$PLATFORM_DIR/grub
 fi
 
 ## Disable kexec supported reboot which was installed by default
@@ -572,7 +578,7 @@ fi
 ## Update initramfs
 sudo chroot $FILESYSTEM_ROOT update-initramfs -u
 ## Convert initrd image to u-boot format
-if [[ $CONFIGURED_ARCH == armhf || $CONFIGURED_ARCH == arm64 ]]; then
+if [[ $TARGET_BOOTLOADER == uboot ]]; then
     INITRD_FILE=initrd.img-${LINUX_KERNEL_VERSION}-${CONFIGURED_ARCH}
     if [[ $CONFIGURED_ARCH == armhf ]]; then
         INITRD_FILE=initrd.img-${LINUX_KERNEL_VERSION}-armmp

build_image.sh

@@ -84,7 +84,7 @@ generate_onie_installer_image()
 
     ## Generate an ONIE installer image
     ## Note: Don't leave blank between lines. It is single line command.
-    ./onie-mk-demo.sh $TARGET_PLATFORM $TARGET_MACHINE $TARGET_PLATFORM-$TARGET_MACHINE-$ONIEIMAGE_VERSION \
+    ./onie-mk-demo.sh $CONFIGURED_ARCH $TARGET_MACHINE $TARGET_PLATFORM-$TARGET_MACHINE-$ONIEIMAGE_VERSION \
           installer platform/$TARGET_MACHINE/platform.conf $output_file OS $IMAGE_VERSION $ONIE_IMAGE_PART_SIZE \
           $ONIE_INSTALLER_PAYLOAD
 }
@@ -111,7 +111,7 @@ if [ "$IMAGE_TYPE" = "onie" ]; then
     mkdir -p `dirname $OUTPUT_ONIE_IMAGE`
     sudo rm -f $OUTPUT_ONIE_IMAGE
 
-    generate_device_list "./installer/$TARGET_PLATFORM/platforms_asic"
+    generate_device_list "./installer/platforms_asic"
 
     generate_onie_installer_image
 
@@ -125,7 +125,7 @@ elif [ "$IMAGE_TYPE" = "raw" ]; then
     mkdir -p `dirname $OUTPUT_RAW_IMAGE`
     sudo rm -f $OUTPUT_RAW_IMAGE
 
-    generate_device_list "./installer/$TARGET_PLATFORM/platforms_asic"
+    generate_device_list "./installer/platforms_asic"
 
     generate_onie_installer_image "$tmp_output_onie_image"
 
@@ -159,7 +159,7 @@ elif [ "$IMAGE_TYPE" = "raw" ]; then
 
 elif [ "$IMAGE_TYPE" = "kvm" ]; then
 
-    generate_device_list "./installer/$TARGET_PLATFORM/platforms_asic"
+    generate_device_list "./installer/platforms_asic"
 
     generate_onie_installer_image
     # Generate single asic KVM image

files/build_templates/sonic_debian_extension.j2

@@ -297,7 +297,7 @@ sudo dpkg --root=$FILESYSTEM_ROOT -i $debs_path/libnss-radius_*.deb || \
 sudo sed -i -e '/^passwd/s/ radius//' $FILESYSTEM_ROOT/etc/nsswitch.conf
 
 # Install a custom version of kdump-tools  (and its dependencies via 'apt-get -y install -f')
-if [[ $CONFIGURED_ARCH == amd64 ]]; then
+if [[ $TARGET_BOOTLOADER == grub ]]; then
 sudo DEBIAN_FRONTEND=noninteractive dpkg --root=$FILESYSTEM_ROOT -i $debs_path/kdump-tools_*.deb || \
     sudo LANG=C DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true chroot $FILESYSTEM_ROOT apt-get -q --no-install-suggests --no-install-recommends install
     cat $IMAGE_CONFIGS/kdump/kdump-tools | sudo tee -a $FILESYSTEM_ROOT/etc/default/kdump-tools > /dev/null

files/image_config/platform/rc.local

@@ -293,7 +293,7 @@ if [ -f $FIRST_BOOT_FILE ]; then
     # we now install a grub for SONiC.
     if [ -n "$onie_platform" ] && [ -n  "$grub_installation_needed" ]; then
 
-        grub_bin=$(ls /host/image-$SONIC_VERSION/platform/x86_64-grub/grub-pc-bin*.deb 2> /dev/null)
+        grub_bin=$(ls /host/image-$SONIC_VERSION/platform/grub/grub*.deb 2> /dev/null)
         if [ -z "$grub_bin" ]; then
             log_migration "Unable to locate grub package !"
             firsttime_exit