Add early kdump support in initramfs.

Kdump service starts too late, so early crashes will have no chance
to get kdump kernel booting, this will cause crash information to be
lost. It is necessary to add a dracut module in order to load crash
kernel and initramfs as early as possible. You can provide "rd.early
kdump" in grub commandline to enable, then the early kdump will load
those files like the normal kdump, which is disabled by default.

For the normal kdump service, it can check whether the early kdump
has loaded the crash kernel and initramfs. It has no conflict with
the early kdump.

If you rebuild the new initramfs for early kdump, the new initramfs
size will become large, because it will put the vmlinuz and kdump
initramfs into the new initramfs.

In addition, early kdump doesn't support fadump.

Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
Reviewed-by: Kazuhito Hagio <khagio@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>

dracut-early-kdump-module-setup.sh

@@ -0,0 +1,44 @@
+#!/bin/bash
+
+. /etc/sysconfig/kdump
+. /lib/kdump/kdump-lib.sh
+
+KDUMP_KERNEL=""
+KDUMP_INITRD=""
+
+check() {
+    if [ ! -f /etc/sysconfig/kdump ] || [ ! -f /lib/kdump/kdump-lib.sh ]\
+        || [ -n "${IN_KDUMP}" ]
+    then
+        return 1
+    fi
+    return 255
+}
+
+depends() {
+    echo "base shutdown"
+    return 0
+}
+
+prepare_kernel_initrd() {
+    KDUMP_BOOTDIR=$(check_boot_dir "${KDUMP_BOOTDIR}")
+    if [ -z "$KDUMP_KERNELVER" ]; then
+        kdump_kver=`uname -r`
+    else
+        kdump_kver=$KDUMP_KERNELVER
+    fi
+    KDUMP_KERNEL="${KDUMP_BOOTDIR}/${KDUMP_IMG}-${kdump_kver}${KDUMP_IMG_EXT}"
+    KDUMP_INITRD="${KDUMP_BOOTDIR}/initramfs-${kdump_kver}kdump.img"
+}
+
+install() {
+    inst_multiple tail find cut dirname hexdump
+    inst_simple "/etc/sysconfig/kdump"
+    inst_binary "/usr/sbin/kexec"
+    inst_binary "/usr/bin/gawk" "/usr/bin/awk"
+    inst_script "/lib/kdump/kdump-lib.sh" "/lib/kdump-lib.sh"
+    inst_hook cmdline 00 "$moddir/early-kdump.sh"
+    prepare_kernel_initrd
+    inst_binary "$KDUMP_KERNEL"
+    inst_binary "$KDUMP_INITRD"
+}

dracut-early-kdump.sh

@@ -0,0 +1,84 @@
+#! /bin/sh
+
+KEXEC=/sbin/kexec
+standard_kexec_args="-p"
+
+EARLY_KDUMP_INITRD=""
+EARLY_KDUMP_KERNEL=""
+EARLY_KDUMP_CMDLINE=""
+EARLY_KDUMP_KERNELVER=""
+EARLY_KEXEC_ARGS=""
+
+. /etc/sysconfig/kdump
+. /lib/dracut-lib.sh
+. /lib/kdump-lib.sh
+
+prepare_parameters()
+{
+    EARLY_KDUMP_CMDLINE=$(prepare_cmdline "${KDUMP_COMMANDLINE}" "${KDUMP_COMMANDLINE_REMOVE}" "${KDUMP_COMMANDLINE_APPEND}")
+    KDUMP_BOOTDIR=$(check_boot_dir "${KDUMP_BOOTDIR}")
+
+    #make early-kdump kernel string
+    if [ -z "$KDUMP_KERNELVER" ]; then
+        EARLY_KDUMP_KERNELVER=`uname -r`
+    else
+        EARLY_KDUMP_KERNELVER=$KDUMP_KERNELVER
+    fi
+
+    EARLY_KDUMP_KERNEL="${KDUMP_BOOTDIR}/${KDUMP_IMG}-${EARLY_KDUMP_KERNELVER}${KDUMP_IMG_EXT}"
+
+    #make early-kdump initrd string
+    EARLY_KDUMP_INITRD="${KDUMP_BOOTDIR}/initramfs-${EARLY_KDUMP_KERNELVER}kdump.img"
+}
+
+early_kdump_load()
+{
+    check_kdump_feasibility
+    if [ $? -ne 0 ]; then
+        return 1
+    fi
+
+    if is_fadump_capable; then
+        echo "WARNING: early kdump doesn't support fadump."
+        return 1
+    fi
+
+    check_current_kdump_status
+    if [ $? == 0 ]; then
+        return 1
+    fi
+
+    prepare_parameters
+
+    EARLY_KEXEC_ARGS=$(prepare_kexec_args "${KEXEC_ARGS}")
+
+    if is_secure_boot_enforced; then
+        echo "Secure Boot is enabled. Using kexec file based syscall."
+        EARLY_KEXEC_ARGS="$EARLY_KEXEC_ARGS -s"
+    fi
+
+    $KEXEC ${EARLY_KEXEC_ARGS} $standard_kexec_args \
+        --command-line="$EARLY_KDUMP_CMDLINE" \
+        --initrd=$EARLY_KDUMP_INITRD $EARLY_KDUMP_KERNEL
+    if [ $? == 0 ]; then
+        echo "kexec: loaded early-kdump kernel"
+        return 0
+    else
+        echo "kexec: failed to load early-kdump kernel"
+        return 1
+    fi
+}
+
+set_early_kdump()
+{
+    if getargbool 0 rd.earlykdump; then
+        echo "early-kdump is enabled."
+        early_kdump_load
+    else
+        echo "early-kdump is disabled."
+    fi
+
+    return 0
+}
+
+set_early_kdump

early-kdump-howto.txt

@@ -0,0 +1,54 @@
+Early Kdump HOWTO
+
+Introduction
+
+Kdump service starts too late, so early crashes will have no chance to get
+kdump kernel booting, this will cause crash information to be lost. It is
+necessary to add a dracut module in order to load crash kernel and initramfs
+as early as possible. You can provide "rd.earlykdump" in grub commandline
+to enable, then the early kdump will load those files like the normal kdump,
+which is disabled by default.
+
+For the normal kdump service, it can check whether the early kdump has loaded
+the crash kernel and initramfs. It has no conflict with the early kdump.
+
+How to configure early kdump:
+
+We assume if you're reading this document, you should already have kexec-tools
+installed.
+
+You can rebuild the initramfs with earlykdump support with below steps:
+1. start kdump service to make sure kdump initramfs is created.
+    # systemctl start kdump
+
+2. rebuild system initramfs with earlykdump support.
+    # dracut --add earlykdump
+
+3. add rd.earlykdump in grub kernel command line.
+
+Note: earlykdump initramfs size will be large because it includes vmlinuz and
+kdump initramfs. And for step 2 if you are sure to overwrite system initramfs
+you can backup the original initramfs and use "--force" option.
+
+After making said changes, reboot your system to take effect. Of course, if you
+want to disable early kdump, you can simply remove "rd.earlykdump" from kernel
+boot parameters in grub, and reboot system like above.
+
+Once the boot is completed, you can check the status of the early kdump support
+on the command prompt:
+
+    # journalctl -x|grep early-kdump
+
+Then, you will see some useful logs, for exapmle:
+
+1. if early kdump is successful.
+Mar 09 09:57:56 localhost.localdomain dracut-cmdline[190]: early-kdump is enabled.
+Mar 09 09:57:56 localhost.localdomain dracut-cmdline[190]: kexec: loaded early-
+kdump kernel
+
+2. if early kdump is disabled.
+Mar 09 10:02:47 localhost.localdomain dracut-cmdline[189]: early-kdump is disabled.
+
+Limitation
+
+At present, early kdump doesn't support fadump.

kexec-tools.spec

@@ -29,6 +29,7 @@ Source24: kdump-lib-initramfs.sh
 Source25: kdump.sysconfig.ppc64le
 Source26: kdumpctl.8
 Source27: live-image-kdump-howto.txt
+Source28: early-kdump-howto.txt
 
 #######################################
 # These are sources for mkdumpramfs
@@ -42,6 +43,8 @@ Source104: dracut-kdump-emergency.service
 Source105: dracut-kdump-error-handler.service
 Source106: dracut-kdump-capture.service
 Source107: dracut-kdump-emergency.target
+Source108: dracut-early-kdump.sh
+Source109: dracut-early-kdump-module-setup.sh
 
 Requires(post): systemd-units
 Requires(preun): systemd-units
@@ -132,6 +135,7 @@ rm -f kexec-tools.spec.in
 cp %{SOURCE10} .
 cp %{SOURCE21} .
 cp %{SOURCE27} .
+cp %{SOURCE28} .
 
 make
 %ifarch %{ix86} x86_64 ppc64 s390x ppc64le aarch64
@@ -190,6 +194,7 @@ make -C kdump-anaconda-addon install DESTDIR=$RPM_BUILD_ROOT
 %find_lang kdump-anaconda-addon
 
 %define remove_dracut_prefix() %(echo -n %1|sed 's/.*dracut-//g')
+%define remove_dracut_early_kdump_prefix() %(echo -n %1|sed 's/.*dracut-early-kdump-//g')
 
 # deal with dracut modules
 mkdir -p -m755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase
@@ -203,6 +208,11 @@ cp %{SOURCE106} $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpb
 cp %{SOURCE107} $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix %{SOURCE107}}
 chmod 755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix %{SOURCE100}}
 chmod 755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix %{SOURCE101}}
+mkdir -p -m755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99earlykdump
+cp %{SOURCE108} $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99earlykdump/%{remove_dracut_prefix %{SOURCE108}}
+cp %{SOURCE109} $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99earlykdump/%{remove_dracut_early_kdump_prefix %{SOURCE109}}
+chmod 755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99earlykdump/%{remove_dracut_prefix %{SOURCE108}}
+chmod 755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99earlykdump/%{remove_dracut_early_kdump_prefix %{SOURCE109}}
 
 
 %define dracutlibdir %{_prefix}/lib/dracut
@@ -301,6 +311,7 @@ done
 %license COPYING
 %doc TODO
 %doc kexec-kdump-howto.txt
+%doc early-kdump-howto.txt
 %doc kdump-in-cluster-environment.txt
 %doc live-image-kdump-howto.txt
 %ifarch %{ix86} x86_64 ppc64 s390x ppc64le aarch64