microcode: add flexability: type & initramfs control

Bug reported that the MICROCODE option did not provide enough
flexability, as it enabled both AMD & Intel options by default, and
placed both sets of microcode into the initramfs.

Existing boolean option MICROCODE is now a string, which takes
no/all/amd/intel as inputs, describing which variant of kernel options
to enable. Boolean inputs are converted to no/all settings. This option
no longer include microcode in initramfs.

New option MICROCODE_INITRAMFS, enabled by default, includes the
microcode for matching kernel config options (INTEL/AMD) into the
initramfs. For users using sys-boot/grub-2.02-r1 or another bootloader
that supports multiple initramfs options, this option can be safely
disabled.

Fixes: https://bugs.gentoo.org/662492
Reported-by: Joerg Schaible <joerg.schaible@gmx.de>
Signed-off-by: Robin H. Johnson <robbat2@gentoo.org>

5 files changed, 43 insertions, 17 deletions

diff --git a/gen_cmdline.sh b/gen_cmdline.sh
index 3d9611fd..853723b7 100755
--- a/gen_cmdline.sh
+++ b/gen_cmdline.sh
@@ -98,8 +98,9 @@ longusage() {
   echo "	--mdadm			Include MDADM/MDMON support"
   echo "	--no-mdadm		Exclude MDADM/MDMON support"
   echo "	--mdadm-config=<file>	Use file as mdadm.conf in initramfs"
-  echo "	--microcode		Include early microcode support"
-  echo "	--no-microcode	Exclude early microcode support"
+  echo "	--microcode[=<type>]	Include early microcode support, for 'all'/'amd'/'intel' CPU types"
+  echo "	--no-microcode			Exclude early microcode support"
+  echo "	--microcode-initramfs	Include early microcode in initramfs"
   echo "	--nfs			Include NFS support"
   echo "	--no-nfs		Exclude NFS support"
   echo "	--dmraid		Include DMRAID support"
@@ -330,9 +331,20 @@ parse_cmdline() {
 			print_info 2 "CMD_BUSYBOX: ${CMD_BUSYBOX}"
 			;;
 		--microcode|--no-microcode)
-			CMD_MICROCODE=`parse_optbool "$*"`
+			case `parse_optbool "$*"` in
+				0) CMD_MICROCODE='no' ;;
+				1) CMD_MICROCODE='all' ;;
+			esac
 			print_info 2 "CMD_MICROCODE: ${CMD_MICROCODE}"
 			;;
+		--microcode=*)
+			CMD_MICROCODE="${*#*=}"
+			print_info 2 "CMD_MICROCODE: $CMD_MICROCODE"
+			;;
+		--microcode-initramfs|--no-microcode-initramfs)
+			CMD_MICROCODE_INITRAMFS=`parse_optbool "$*"`
+			print_info 2 "CMD_MICROCODE_INITRAMFS: ${CMD_MICROCODE_INITRAMFS}"
+			;;
 		--nfs|--no-nfs)
 			CMD_NFS=`parse_optbool "$*"`
 			print_info 2 "CMD_NFS: ${CMD_NFS}"
diff --git a/gen_configkernel.sh b/gen_configkernel.sh
index 697c478d..475526ab 100755
--- a/gen_configkernel.sh
+++ b/gen_configkernel.sh
@@ -277,17 +277,15 @@ config_kernel() {
 
 	# Microcode setting, intended for early microcode loading
 	# needs to be compiled in.
-	if isTrue ${MICROCODE}
+	kconfig_microcode_intel=(CONFIG_MICROCODE_INTEL CONFIG_MICROCODE_INTEL_EARLY)
+	kconfig_microcode_amd=(CONFIG_MICROCODE_AMD CONFIG_MICROCODE_AMD_EARLY)
+	if [[ -n "${MICROCODE}" ]]
 	then
-		for k in \
-			CONFIG_MICROCODE \
-			CONFIG_MICROCODE_INTEL \
-			CONFIG_MICROCODE_AMD \
-			CONFIG_MICROCODE_OLD_INTERFACE \
-			CONFIG_MICROCODE_INTEL_EARLY \
-			CONFIG_MICROCODE_AMD_EARLY \
-			CONFIG_MICROCODE_EARLY \
-			; do
+		kconfigs=(CONFIG_MICROCODE CONFIG_MICROCODE_OLD_INTERFACE CONFIG_MICROCODE_EARLY)
+		[[ "$MICROCODE" == all ]] && kconfigs+=( ${kconfig_microcode_amd[@]} ${kconfig_microcode_intel[@]} )
+		[[ "$MICROCODE" == amd ]] && kconfigs+=( ${kconfig_microcode_amd[@]} )
+		[[ "$MICROCODE" == intel ]] && kconfigs+=( ${kconfig_microcode_intel[@]} )
+		for k in "${kconfigs[@]}" ; do
 			cfg=$(kconfig_get_opt "${KERNEL_OUTPUTDIR}/.config" "$k")
 			case "$cfg" in
 				y) ;; # Do nothing
diff --git a/gen_determineargs.sh b/gen_determineargs.sh
index b686fca9..bd0150a5 100755
--- a/gen_determineargs.sh
+++ b/gen_determineargs.sh
@@ -121,7 +121,8 @@ determine_real_args() {
 	set_config_with_override BOOL   HYPERV               CMD_HYPERV
 	set_config_with_override BOOL   BUSYBOX              CMD_BUSYBOX              "yes"
 	set_config_with_override BOOL   NFS                  CMD_NFS                  "yes"
-	set_config_with_override BOOL   MICROCODE            CMD_MICROCODE
+	set_config_with_override STRING MICROCODE            CMD_MICROCODE            "all"
+	set_config_with_override BOOL   MICROCODE_INITRAMFS  CMD_MICROCODE_INITRAMFS  "yes"
 	set_config_with_override BOOL   UNIONFS              CMD_UNIONFS
 	set_config_with_override BOOL   NETBOOT              CMD_NETBOOT
 	set_config_with_override STRING REAL_ROOT            CMD_REAL_ROOT
@@ -234,5 +235,13 @@ determine_real_args() {
 		INTEGRATED_INITRAMFS=0
 	fi
 
+	MICROCODE=${MICROCODE,,}
+	case ${MICROCODE} in
+		all|amd|intel) ;;
+		y|yes|1|true|t) MICROCODE='all' ;;
+		n|no|none|0|false|f) MICROCODE='' ;;
+		*) gen_die "Invalid microcode '${MICROCODE}', --microcode=<type> requires one of: no, all, intel, amd" ;;
+	esac
+
 	get_KV
 }
diff --git a/gen_initramfs.sh b/gen_initramfs.sh
index 768f2915..a2c55c6e 100755
--- a/gen_initramfs.sh
+++ b/gen_initramfs.sh
@@ -1149,7 +1149,8 @@ create_initramfs() {
 		## It only loads monolithic ucode from an uncompressed cpio, which MUST
 		## be before the other cpio archives in the stream.
 		cfg_CONFIG_MICROCODE=$(kconfig_get_opt "${KERNEL_OUTPUTDIR}"/.config CONFIG_MICROCODE)
-		if isTrue "${MICROCODE}" && [ "${cfg_CONFIG_MICROCODE}" == "y" ]; then
+		if isTrue "${MICROCODE_INITRAMFS}" && [ "${cfg_CONFIG_MICROCODE}" == "y" ]; then
+			print_info 1 "--microcode-initramfs is enabled by default for compatability but made obsolete by sys-boot/grub-2.02-r1"
 			cfg_CONFIG_MICROCODE_INTEL=$(kconfig_get_opt "${KERNEL_OUTPUTDIR}"/.config CONFIG_MICROCODE_INTEL)
 			cfg_CONFIG_MICROCODE_AMD=$(kconfig_get_opt "${KERNEL_OUTPUTDIR}"/.config CONFIG_MICROCODE_AMD)
 			print_info 1 "early-microcode: >> Preparing..."
diff --git a/genkernel.conf b/genkernel.conf
index 5e5a67b7..57cb2b0d 100644
--- a/genkernel.conf
+++ b/genkernel.conf
@@ -74,8 +74,14 @@ USECOLOR="yes"
 # Add in GnuPG support
 #GPG="no"
 
-# Add in early microcode support
-#MICROCODE="no"
+# Add in early microcode support: this sets the kernel options for early microcode loading
+# Acceptible values: empty/"no", "all", "intel", "amd"
+#MICROCODE="all"
+
+# Include early microcode in generated initramfs
+# This is enabled by default for upgrade compatability, however is obsoleted by
+# sys-boot/grub-2.02-r1, which supports multiple initramfs in the bootloader.
+#MICROCODE_INITRAMFS="no"
 
 # Add in NFS support
 #NFS="no"