kdumpctl: Add basic UKI support

A Unified Kernel Image (UKI) is a single EFI PE executable combining an
EFI stub, a kernel image, an initrd image, and the kernel command line.
They are defined in the Boot Loader Specification [1] as type #2
entries. UKIs have the advantage that all code as well as meta data that
is required to boot the system, not only the kernel image, is combined
in a single PE file and can be signed for EFI SecureBoot. This extends
the coverage of SecureBoot extensively.

For RHEL support for UKI were included into kernel-ark with 16c7e3ee836e
("redhat: Add sub-RPM with a EFI unified kernel image for virtual
machines").

There are two problems with UKIs from the kdump point of view at the
moment. First, they cannot be directly loaded via kexec_file_load and
second, the initrd included isn't suitable for kdump. In order to enable
kdump on systems with UKIs build the kdump initrd as usual and extract
the kernel image before loading the crash kernel.

[1] https://uapi-group.org/specifications/specs/boot_loader_specification/

Signed-off-by: Philipp Rudo <prudo@redhat.com>
Reviewed-by: Pingfan Liu <piliu@redhat.com>
Reviewed-by: Coiby Xu <coxu@redhat.com>

kdump-lib.sh

@@ -11,6 +11,17 @@ fi
 FADUMP_ENABLED_SYS_NODE="/sys/kernel/fadump_enabled"
 FADUMP_REGISTER_SYS_NODE="/sys/kernel/fadump_registered"
 
+is_uki()
+{
+	local img
+
+	img="$1"
+
+	[[ -f "$img" ]] || return
+	[[ "$(file -b --mime-type "$img")" == application/x-dosexec ]] || return
+	objdump -h -j .linux "$img" &> /dev/null
+}
+
 is_fadump_capable()
 {
 	# Check if firmware-assisted dump is enabled
@@ -489,7 +500,9 @@ prepare_kdump_kernel()
 	read -r machine_id < /etc/machine-id
 
 	boot_dirlist=${KDUMP_BOOTDIR:-"/boot /boot/efi /efi /"}
-	boot_imglist="$KDUMP_IMG-$kdump_kernelver$KDUMP_IMG_EXT $machine_id/$kdump_kernelver/$KDUMP_IMG"
+	boot_imglist="$KDUMP_IMG-$kdump_kernelver$KDUMP_IMG_EXT \
+		$machine_id/$kdump_kernelver/$KDUMP_IMG \
+		EFI/Linux/$machine_id-$kdump_kernelver.efi"
 
 	# The kernel of OSTree based systems is not in the standard locations.
 	if is_ostree; then
@@ -562,7 +575,11 @@ prepare_kdump_bootinfo()
 	fi
 
 	# Set KDUMP_BOOTDIR to where kernel image is stored
-	KDUMP_BOOTDIR=$(dirname "$KDUMP_KERNEL")
+	if is_uki "$KDUMP_KERNEL"; then
+		KDUMP_BOOTDIR=/boot
+	else
+		KDUMP_BOOTDIR=$(dirname "$KDUMP_KERNEL")
+	fi
 
 	# Default initrd should just stay aside of kernel image, try to find it in KDUMP_BOOTDIR
 	boot_initrdlist="initramfs-$KDUMP_KERNELVER.img initrd"
@@ -715,6 +732,11 @@ prepare_cmdline()
 	# may cause the hot-remove of some pci hotplug device.
 	is_aws_aarch64 && out=$(echo "$out" | sed -e "/\<irqpoll\>//")
 
+	# Always disable gpt-auto-generator as it hangs during boot of the
+	# crash kernel. Furthermore we know which disk will be used for dumping
+	# (if at all) and add it explicitly.
+	is_uki "$KDUMP_KERNEL" && out+="rd.systemd.gpt_auto=no "
+
 	# Trim unnecessary whitespaces
 	echo "$out" | sed -e "s/^ *//g" -e "s/ *$//g" -e "s/ \+/ /g"
 }

kdumpctl

@@ -694,7 +694,7 @@ function remove_kdump_kernel_key()
 # as the currently running kernel.
 load_kdump()
 {
-	local ret
+	local ret uki
 
 	KEXEC_ARGS=$(prepare_kexec_args "${KEXEC_ARGS}")
 	KDUMP_COMMANDLINE=$(prepare_cmdline "${KDUMP_COMMANDLINE}" "${KDUMP_COMMANDLINE_REMOVE}" "${KDUMP_COMMANDLINE_APPEND}")
@@ -707,6 +707,16 @@ load_kdump()
 		load_kdump_kernel_key
 	fi
 
+	if is_uki "$KDUMP_KERNEL"; then
+		uki=$KDUMP_KERNEL
+		KDUMP_KERNEL=$KDUMP_TMPDIR/vmlinuz
+		objcopy -O binary --only-section .linux "$uki" "$KDUMP_KERNEL"
+		sync -f "$KDUMP_KERNEL"
+		# Make sure the temp file has the correct SELinux label.
+		# Otherwise starting the kdump.service will fail.
+		chcon -t boot_t "$KDUMP_KERNEL"
+	fi
+
 	ddebug "$KEXEC $KEXEC_ARGS $standard_kexec_args --command-line=$KDUMP_COMMANDLINE --initrd=$TARGET_INITRD $KDUMP_KERNEL"
 
 	# The '12' represents an intermediate temporary file descriptor

kexec-tools.spec

@@ -66,6 +66,7 @@ Requires: dracut-network >= 050
 Requires: dracut-squash >= 050
 Requires: ethtool
 Requires: util-linux
+Requires: binutils
 Recommends: grubby
 Recommends: hostname
 BuildRequires: make