aemfvp-a/run-model: Add SATA device parameters to support distro boot

Also, add the following changes to this patch:
1. Add changes for accessing Terminal-0 via Telnet if the Armv-A
   Base AEM FVP is running on non-Xserver support.
2. Add separate scripts for busybox and distro boot support
   on Armv-A Base AEM FVP.
Signed-off-by: Selvarasu Ganesan <Selvarasu.Ganesan@arm.com>
Change-Id: I06a7a31be749f5fe88c9b2c148d1e787ede7b70f

aemfvp-a/boot.sh

+#!/bin/bash
+
+# Copyright (c) 2021, ARM Limited and Contributors. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# Redistributions of source code must retain the above copyright notice, this
+# list of conditions and the following disclaimer.
+#
+# Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# Neither the name of ARM nor the names of its contributors may be used
+# to endorse or promote products derived from this software without specific
+# prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+readonly bootloader_options=(
+"uefi"
+"u-boot"
+)
+
+#Set default bootloader
+bootloader="uefi"
+
+#Set default platform
+platform="aemfvp-a"
+
+#Network disabled by default
+net_enable="false"
+
+__print_examples()
+{
+	echo "Example 1: ./boot.sh"
+	echo "  Starts the execution of the $1 model and the software boots upto the"
+	echo "  busybox prompt. Here the default platform and bootloader"
+	echo "  selections are \"aemfvp-a\" and \"uefi\""
+	echo ""
+	echo "Example 2: ./boot.sh -p $1"
+	echo "  Starts the execution of the $1 model and the software boots upto the"
+	echo "  busybox prompt. Here the default bootloader selection is \"uefi\""
+	echo ""
+	echo "Example 3: ./boot.sh -p $1 -b [uefi|u-boot]"
+	echo "  Starts the execution of the $1 model and the software boots upto the"
+	echo "  busybox prompt. The selection of the bootloader to be either uefi or u-boot"
+	echo "  is based on command line parameters."
+	echo ""
+	echo "Example 4: ./boot.sh -p $1 -b [uefi|u-boot] -n true"
+	echo "  Starts the execution of the $1 model and the software boots upto the"
+	echo "  busybox prompt. The selection of the bootloader to be either uefi or u-boot"
+	echo "  is based on command line parameters. The model supports networking allowing"
+	echo "  the software running within the model to access the network."
+	echo ""
+}
+
+print_usage ()
+{
+	echo ""
+	echo "Boots upto busybox console on a specified platform."
+	echo "Usage: ./boot.sh -p <platform> [-b <uefi|u-boot>] [-n <true|false>]"
+	echo ""
+	echo "Supported command line parameters - "
+	echo "  -p   Specifies the platform to be selected \(default/optional\)"
+	echo "		Supported platform is -"
+	echo "	     	aemfvp-a"
+	echo "  -b   Specifies the bootloader to be selected \(optional\)"
+	echo "		Supported bootloader options are -"
+	echo "		${bootloader_options[@]}"
+	echo "  -n   Enable or disable network controller support on the platform \(optional\)."
+	echo "       If not specified, network support is disabled by default."
+	echo ""
+	__print_examples "aemfvp-a"
+	echo ""
+}
+
+while getopts "p:b:n:h" opt; do
+	case $opt in
+		p)
+			platform=$OPTARG
+			;;
+		b)
+			bootloader=$OPTARG
+			;;
+		n)
+			net_enable=$OPTARG
+			;;
+		*)
+			print_usage
+			exit 1
+			;;
+	esac
+done
+
+__parse_params_validate()
+{
+	#Ensure that the platform is supported
+	if [ -z "$platform" ] ; then
+		print_usage
+		exit 1
+	fi
+	if [ "$platform" != "aemfvp-a" ]; then
+		echo "[ERROR] Could not deduce which platform to execute on."
+		echo "Supported platform is -"
+		echo "aemfvp-a"
+		exit 1
+	fi
+}
+
+#Ensure that the platform is supported
+__parse_params_validate
+
+if [ "${bootloader}" != "uefi" ] && [ "${bootloader}" != "u-boot" ] ;then
+	echo "[ERROR] Invalid bootloader selection"
+	print_usage
+	exit 1
+
+fi
+
+if [ "${net_enable}" != "true" ] && [ "${net_enable}" != "false" ]; then
+	echo "[ERROR] Unsupported <network_enabled> selected"
+	print_usage
+	exit 1;
+fi
+
+out_dir="output/$platform"
+
+BL1="$out_dir/$platform/tf-bl1.bin"
+
+if [ "$bootloader" == "u-boot" ]; then
+	FIP="$out_dir/$platform/fip-uboot.bin"
+	IMAGE="$out_dir/$platform/Image"
+	DTB="$out_dir/$platform/fvp-base-revc.dtb"
+else
+	FIP="$out_dir/$platform/fip-uefi.bin"
+fi
+
+if  [ "${net_enable}" == "true" ]; then
+	NET=1
+fi
+
+DISK="$out_dir/components/$platform/grub-busybox.img"
+
+source ./model-scripts/$platform/run_model.sh

aemfvp-a/distro.sh

+#!/bin/bash
+
+# Copyright (c) 2021, ARM Limited and Contributors. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# Redistributions of source code must retain the above copyright notice, this
+# list of conditions and the following disclaimer.
+#
+# Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# Neither the name of ARM nor the names of its contributors may be used
+# to endorse or promote products derived from this software without specific
+# prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+installer_image=""
+disk_size=""
+mode=""
+
+#Set default platform
+platform="aemfvp-a"
+
+#Network disabled by default
+net_enable="false"
+
+install ()
+{
+
+	#Sata disk output directory
+	mkdir -p "$PWD/satadisk"
+
+	export SATADISK_IMAGE_PATH="$PWD/satadisk/$RANDOM.satadisk"
+
+	# Create a disk of $disk_size GB
+	dd if=/dev/zero of=$SATADISK_IMAGE_PATH bs=1G count=$disk_size
+
+	echo "Created $SATADISK_IMAGE_PATH of size $disk_size GB, proceeding to install $installer_image ..."
+
+	./model-scripts/$platform/run_model.sh  -f distro
+}
+
+
+boot ()
+{
+	# Check if an installed sata disk image is supplied. If yes, boot from it.
+	if [ ! -z "$disk_image" ] ; then
+		dir_name="$(dirname $disk_image)"
+		if [ $dir_name == "." ] ; then
+			disk_image="$PWD/$disk_image"
+		fi
+		echo "Proceeding to boot supplied disk image name: $disk_image ..."
+		export SATADISK_IMAGE_PATH=$disk_image
+		./model-scripts/$platform/run_model.sh -f distro
+		exit 0
+	fi
+
+	# If $disk_image is not specified, see if there are more than one
+	# .satadisk files, if so, prompt the user to pick one with -d.
+	# If there is exactly one available, boot it. If there are none, prompt
+	# the user to install with -i/-s
+
+	available_images=$(find . -name "*.satadisk")
+	num_available_images=$(echo $available_images | wc -w)
+
+	case $num_available_images in
+		1)
+			# In the case of exactly one, the list of images will
+			# be the image name so just use it
+			echo "Found $available_images, proceeding to boot ..."
+			available_images=$PWD/$available_images
+			export SATADISK_IMAGE_PATH=$available_images
+
+			./model-scripts/$platform/run_model.sh -f distro
+			;;
+		*)
+			if [[ -z "$disk_image" ]]; then
+				echo "Found several available images:"
+				echo ""
+				echo $available_images | sed 's/\.\///g' | tr ' ' '\n'
+				echo ""
+				echo "Please choose one using distro_boot -d [disk_image]"
+				echo ""
+			fi
+			;;
+	esac
+}
+
+__print_examples()
+{
+	echo "Example 1: ./distro.sh -p $1 -i Fedora-Server-dvd-aarch64-34-1.2.iso -s 16"
+	echo "  Installs Fedora 34 on to a 16 GB disk."
+	echo ""
+	echo "Example 2: ./distro.sh -p $1"
+	echo "  Finds an available installed disk image and boots from it."
+	echo ""
+	echo "Example 3: ./distro.sh -p $1 -d fedora34.satadisk"
+	echo "  Boot from an existing installed disk image"
+}
+
+print_usage ()
+{
+	echo ""
+	echo "Install or boot linux distribution."
+	echo "Usage: ./distro.sh -p <platform> -i <image> -s <disk size> [-d <disk image>] [-n <true|false>]"
+	echo ""
+	echo "Supported command line parameters:"
+	echo "  -p   platform name (optional)"
+	echo "		Supported platform is -"
+	echo "		aemfvp-a"
+	echo "  -i   Image, takes a path to an iso installer image (mandatory for installation)"
+	echo "  -s   Disk size in GB (mandatory for installation)"
+	echo "  -d   Disk image with previously installed distro, used for"
+	echo "       disambiguation if there are more than one installed"
+	echo "       concurrently."
+	echo "  -n   Enable network: true or false (default: false)"
+	echo ""
+	__print_examples "aemfvp-a"
+	echo ""
+}
+
+while getopts "p:i:s:d:n:h" opt; do
+	case $opt in
+		p)
+			platform=$OPTARG
+			;;
+		i)
+			installer_image=$OPTARG
+			;;
+		s)
+			disk_size=$OPTARG
+			;;
+		d)
+			disk_image=$OPTARG
+			;;
+		n)
+			net_enable=$OPTARG
+			;;
+		*)
+			print_usage
+			exit 1
+			;;
+	esac
+done
+
+# Either an installer and a disk size is specified or neither.
+# If they are specified, create a new disk and boot the model with those params
+# if not, check for an existing .satadisk file and use that to boot from
+# otherwise throw an error
+
+if [[ ! -z $disk_size ]] && [[ ! -z $installer_image ]]; then
+	mode="install"
+elif [[ -z $disk_size ]] && [[ -z $installer_image ]]; then
+
+	# There is no need to separate the boot from single / multiple images
+	# at this stage, we can handle that in boot()
+	mode="boot"
+else
+	print_usage
+	exit 1
+fi
+
+__parse_params_validate()
+{
+	#Ensure that the platform is supported
+	if [ -z "$platform" ] ; then
+		print_usage
+		exit 1
+	fi
+	if [ "$platform" != "aemfvp-a" ]; then
+		echo "[ERROR] Could not deduce which platform to execute on."
+		echo "Supported platform is -"
+		echo "aemfvp-a"
+		exit 1
+	fi
+}
+#Ensure that the platform is supported
+__parse_params_validate
+
+out_dir="output/$platform"
+export BL1="$out_dir/$platform/tf-bl1.bin"
+export FIP="$out_dir/$platform/fip-uefi.bin"
+export DISK=$installer_image
+
+if [ "${net_enable}" != "true" ] && [ "${net_enable}" != "false" ]; then
+	echo "[ERROR] Unsupported <network_enabled> selected"
+	print_usage
+	exit 1;
+fi
+
+if  [ "${net_enable}" == "true" ]; then
+	export NET=1
+fi
+
+case $mode in
+	install)
+		install
+		;;
+	boot)
+		boot
+		;;
+	*)
+		echo "Unknown mode"
+		exit 1
+		;;
+esac

fvp/run_model.sh → aemfvp-a/run_model.sh

 #!/bin/bash
 
-# Copyright (c) 2015, ARM Limited and Contributors. All rights reserved.
+# Copyright (c) 2015-2021, ARM Limited and Contributors. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are met:
@@ -30,52 +30,32 @@
 
 err=0
 
-function usage
-{
-	echo "usage: $0 [--aarch32] [rundir]"
-	echo "Options:"
-	echo "  --aarch32    run the model in Aarch32 mode, if available"
-	echo "  [rundir]     the script will run from a directory specified on the commandline"
-	echo "               otherwise it will run from the current working directory"
-	echo "               use this to tell the model where to find the binaries you want"
-	echo "               to load if they aren't in the current directory."
-	exit
-}
+MODEL_TYPE="aemfvp-a"
+
+# Set default fs_type
+FS_TYPE="busybox"
 
 while [ "$1" != "" ]; do
 	case $1 in
-		"-h" | "-?" | "-help" | "--help" | "--h" | "help" )
-			usage
-			exit
-			;;
-		"--aarch32" | "--Aarch32" | "--AARCH32" )
-			model_arch=aarch32
-			;;
 		"--aarch64" | "--Aarch64" | "--AARCH64" )
 			model_arch=aarch64
 			;;
-		*)
-			if [ "$rundir" == "" ]
-			then
-				rundir=$1
+		-f)
+			shift
+			if test $# -gt 0; then
+				FS_TYPE=$1
 			fi
+			shift
 			;;
 	esac
 	shift
 done
 
 model_arch=${model_arch:-aarch64}
-rundir=${rundir:-.}
 
-if [ -e $rundir ]; then
-	cd $rundir
-else
-	echo "ERROR: the run directory to $rundir, however that path does not exist"
-	exit 1
-fi
 
-CLUSTER0_NUM_CORES=${CLUSTER0_NUM_CORES:-1}
-CLUSTER1_NUM_CORES=${CLUSTER1_NUM_CORES:-1}
+CLUSTER0_NUM_CORES=${CLUSTER0_NUM_CORES:-4}
+CLUSTER1_NUM_CORES=${CLUSTER1_NUM_CORES:-4}
 
 # Check for obvious errors and set err=1 if we encounter one
 if [ ! -e "$MODEL" ]; then
@@ -88,27 +68,15 @@ else
 
 	case $version in
 		*Foundation* )
-			model_type=foundation
-			DTB=${DTB:-foundation-v8-gicv3.dtb}
+			err=1
 			;;
 		*Cortex_A32* )
-			model_type=cortex-a32
-			DTB=${DTB:-fvp-base-aemv8a-aemv8a.dtb}
+			err=1
 			;;
 		* )
 			model_type=aemv8
 			DTB=${DTB:-fvp-base-aemv8a-aemv8a.dtb}
-			if [ "$model_arch" == "aarch32" ]; then
-				arch_params="	-C cluster0.cpu0.CONFIG64=0                                 \
-						-C cluster0.cpu1.CONFIG64=0                                 \
-						-C cluster0.cpu2.CONFIG64=0                                 \
-						-C cluster0.cpu3.CONFIG64=0                                 \
-						-C cluster1.cpu0.CONFIG64=0                                 \
-						-C cluster1.cpu1.CONFIG64=0                                 \
-						-C cluster1.cpu2.CONFIG64=0                                 \
-						-C cluster1.cpu3.CONFIG64=0                                 \
-						"
-			fi
+
 			cores="-C cluster0.NUM_CORES=$CLUSTER0_NUM_CORES \
 				-C cluster1.NUM_CORES=$CLUSTER1_NUM_CORES"
 			;;
@@ -176,7 +144,6 @@ SECURE_MEMORY=${SECURE_MEMORY:-0}
 echo "Running FVP Base Model with these parameters:"
 echo "MODEL=$MODEL"
 echo "model_arch=$model_arch"
-echo "rundir=$rundir"
 echo "BL1=$BL1"
 echo "FIP=$FIP"
 echo "IMAGE=$IMAGE"
@@ -188,120 +155,127 @@ echo "CLUSTER0_NUM_CORES=$CLUSTER0_NUM_CORES"
 echo "CLUSTER1_NUM_CORES=$CLUSTER1_NUM_CORES"
 echo "SECURE_MEMORY=$SECURE_MEMORY"
 echo "NET=$NET"
+echo "TAP_INTERFACE=$TAP_INTERFACE"
+echo "SATADISK_IMAGE_PATH=$SATADISK_IMAGE_PATH"
 
 kern_addr=0x80080000
-dtb_addr=0x82000000
+dtb_addr=0x83000000
 initrd_addr=0x84000000
 
-if [ "$model_type" == "foundation" ]; then
-	GICV3=${GICV3:-1}
-	echo "GICV3=$GICV3"
-
-	if [ "$NET" == "1" ]; then
-		# The Foundation Model MAC address appears to be 00:02:F7:EF
-		# followed by the last two bytes of the host's MAC address.
-		net="--network bridged --network-bridge=ARM$USER"
-	fi
-
-	if [ "$DISK" != "" ]; then
-		disk_param=" --block-device=$DISK " 
-	fi
+CACHE_STATE_MODELLED=${CACHE_STATE_MODELLED:=0}
+echo "CACHE_STATE_MODELLED=$CACHE_STATE_MODELLED"
 
-	if [ "$SECURE_MEMORY" == "1" ]; then
-		secure_memory_param=" --secure-memory"
+# search all the available network interfaces and find an available tap
+# network interface to use.
+find_tap_interface()
+{
+	echo -e "\n[INFO] Finding available TAP interface..."
+	if [[ -n "$TAP_NAME" ]]; then
+		TAP_INTERFACE=$TAP_NAME
 	else
-		secure_memory_param=" --no-secure-memory"
+		echo -e "\n[WARN] Environment variable TAP_NAME is not defined."
+		echo -e "[INFO] If you want to use a particular interface then please export TAP_NAME with the interface name."
+		echo -e "[INFO] Searching for available TAP device(s)..."
+		ALL_INTERFACES=`ifconfig -a | sed 's/[ \t].*//;/^\(lo\|\)$/d'`
+		while read -r line; do
+			last_char="${line: -1}"
+			#On machines with ubuntu 18.04+, the interface name ends with ":" character.
+			#Strip this character from the network interface name.
+			if [ "$last_char" == ":" ]; then
+				TAP_INTERFACE=${line::-1}
+			else
+				TAP_INTERFACE=$line
+			fi
+			# The file tun_flags will only be available under tap interface directory.
+			# Incase of multiple tap interfaces, only the first available tap interface will be used.
+			if [ -f "/sys/class/net/$TAP_INTERFACE/tun_flags" ];then
+				break;
+			fi
+		done <<< "$ALL_INTERFACES"
 	fi
-
-	if [ "$GICV3" == "1" ]; then
-		gic_param=" --gicv3"
+	if [[ -z "$TAP_INTERFACE" ]]; then
+		echo -e "[WARN] No TAP interface found !!! Please create a new tap interface for network to work inside the model."
+		return 1
 	else
-		gic_param=" --no-gicv3"
+		echo -e "[INFO] Interface Found : $TAP_INTERFACE"
 	fi
+	return 0
+}
 
-	if [ "$IMAGE" != "" ]; then
-		image_param="--data=${IMAGE}@${kern_addr}"
-	fi
-	if [ "$INITRD" != "" ]; then
-		initrd_param="--data=${INITRD}@${initrd_addr}"
-	fi
-	if [ "$DTB" != "" ]; then
-		dtb_param="--data=${DTB}@${dtb_addr}"
+if [ "$NET" == "1" ]; then
+	find_tap_interface
+	if [[ -z $TAP_INTERFACE ]]; then
+		echo "[ERROR] network interface name is empty"
+		exit 1;
 	fi
 
-	cmd="$MODEL \
-	--cores=$CLUSTER0_NUM_CORES \
-	$secure_memory_param \
-	--visualization \
-	--use-real-time \
-	$gic_param \
-	--data=${BL1}@0x0 \
-	--data=${FIP}@0x8000000 \
-	$image_param \
-	$dtb_param \
-	$initrd_param \
-	$disk_param \
-	$net \
-	--arm-v8.0
-	"
-else
-	CACHE_STATE_MODELLED=${CACHE_STATE_MODELLED:=0}
-	echo "CACHE_STATE_MODELLED=$CACHE_STATE_MODELLED"
-
-	if [ "$NET" == "1" ]; then
-		if [ "$MACADDR" == "" ]; then
-			# if the user didn't supply a MAC address, generate one
-			MACADDR=`echo -n 00:02:F7; dd bs=1 count=3 if=/dev/random 2>/dev/null |hexdump -v -e '/1 ":%02X"'`
-			echo MACADDR=$MACADDR
-		fi
+	if [ "$MACADDR" == "" ]; then
+		# if the user didn't supply a MAC address, generate one
+		MACADDR=`echo -n 00:02:F7; dd bs=1 count=3 if=/dev/random 2>/dev/null |hexdump -v -e '/1 ":%02X"'`
+		echo MACADDR=$MACADDR
+	fi
 
-		net="-C bp.hostbridge.interfaceName=ARM$USER \
+	net="-C bp.hostbridge.interfaceName=$TAP_INTERFACE \
 		-C bp.smsc_91c111.enabled=true \
 		-C bp.smsc_91c111.mac_address=${MACADDR}"
-	fi
+fi
 
-	if [ "$DISK" != "" ]; then
-		disk_param=" -C bp.virtioblockdevice.image_path=$DISK "
-	fi
+if [[ ! -z $FS_TYPE ]] && [ ${FS_TYPE,,} == "distro" ]; then
 
-	if [ "$IMAGE" != "" ]; then
-		image_param="--data cluster0.cpu0=${IMAGE}@${kern_addr}"
-	fi
-	if [ "$INITRD" != "" ]; then
-		initrd_param="--data cluster0.cpu0=${INITRD}@${initrd_addr}"
-	fi
-	if [ "$DTB" != "" ]; then
-		dtb_param="--data cluster0.cpu0=${DTB}@${dtb_addr}"
+	if [[ -n "$SATADISK_IMAGE_PATH" ]]; then
+		sata_disk_path="-C pci.ahci_pci.ahci.image_path=${SATADISK_IMAGE_PATH}"
+	else
+		echo "Error:Valid SATA hard disk image required to install the distribution image."
+		echo "Please create sata disk image and export using SATADISK_IMAGE_PATH variable"
+		exit 1
 	fi
+	remove_unused_virtio="-C pci.pcidevice0.bus=0xFF \