linux-kernel - Re: x86/microcode update on systems without INITRD

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Message-ID: <20160111194311.GF4686@pd.tnic>
Date:	Mon, 11 Jan 2016 20:43:11 +0100
From:	Borislav Petkov <bp@...e.de>
To:	Michal Marek <mmarek@...e.cz>
Cc:	Markus Trippelsdorf <markus@...ppelsdorf.de>,
	Måns Rullgård <mans@...sr.com>,
	Thomas Voegtle <tv@...96.de>, linux-kernel@...r.kernel.org
Subject: Re: x86/microcode update on systems without INITRD

On Fri, Jan 08, 2016 at 03:48:37PM +0100, Michal Marek wrote:
> The comments are printed during make oldconfig if a symbol in the
> current menu needs updating. Which is probably not the case here, both
> MICROCODE and BLK_DEV_INITRD are existing symbols.

Right, and the problem is that "make oldconfig" sees that BLK_DEV_INITRD
is not enabled in that case and disables CONFIG_MICROCODE too. So by the time
the comment gets evaluated, CONFIG_MICROCODE is off so no workie.

I tried a different thing, see below. It is a bit lengthly but it does
what it should and we can always extend it for other stuff later as it
might turn useful, according to my suspicion :-)

With Thomas' config it says:

$ make oldconfig
You have CONFIG_MICROCODE enabled without BLK_DEV_INITRD. Enable
it and make sure microcode is added to your initrd as explained in
Documentation/x86/early-microcode.txt

scripts/kconfig/Makefile:85: recipe for target 'oldconfig' failed
make[1]: *** [oldconfig] Error 1
Makefile:531: recipe for target 'oldconfig' failed
make: *** [oldconfig] Error 2


It needs to be made to look at CONFIG_MODULES and make that warning just
a hint. I'll have to think about it more...

Thoughts?

---
 arch/x86/scripts/check-configs.sh | 41 +++++++++++++++++++++++++++++++++++++++
 scripts/kconfig/Makefile          |  3 +++
 2 files changed, 44 insertions(+)
 create mode 100644 arch/x86/scripts/check-configs.sh

diff --git a/arch/x86/scripts/check-configs.sh b/arch/x86/scripts/check-configs.sh
new file mode 100644
index 000000000000..51ae9bde6965
--- /dev/null
+++ b/arch/x86/scripts/check-configs.sh
@@ -0,0 +1,41 @@
+#!/bin/bash
+
+if [ "$1" != "oldconfig" ]; then
+	exit 0
+fi
+
+srctree=$2
+ARCH="$3"
+UNAME_RELEASE=$(uname -r)
+
+KCONFIGS=".config /lib/modules/$UNAME_RELEASE/.config /etc/kernel-config /boot/config-$UNAME_RELEASE"
+
+if [ "$ARCH" = "X86_32" ]; then
+	KCONFIGS="$KCONFIGS $srctree/arch/x86/configs/i386_defconfig"
+else
+	KCONFIGS="$KCONFIGS $srctree/arch/x86/configs/x86_64_defconfig"
+fi
+
+for k in $KCONFIGS;
+do
+	if [ -e $k ]; then
+		OLD_CONFIG=$k
+		break
+	fi
+done
+
+if [ -z "$OLD_CONFIG" ]; then exit 0; fi
+
+# Check optimal microcode loader .config settings
+if ! grep -q MICROCODE $OLD_CONFIG; then
+	exit 0
+fi
+
+MSG="You have CONFIG_MICROCODE enabled without BLK_DEV_INITRD. Enable\n\
+it and make sure microcode is added to your initrd as explained in\n\
+Documentation/x86/early-microcode.txt\n"
+
+if ! grep -v "^#" $OLD_CONFIG | grep -q BLK_DEV_INITRD; then
+	echo -e $MSG
+	exit 1
+fi
diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile
index d79cba4ce3eb..136ae9744efc 100644
--- a/scripts/kconfig/Makefile
+++ b/scripts/kconfig/Makefile
@@ -81,6 +81,9 @@ simple-targets := oldconfig allnoconfig allyesconfig allmodconfig \
 PHONY += $(simple-targets)
 
 $(simple-targets): $(obj)/conf
+ifneq ($(wildcard $(srctree)/arch/$(SRCARCH)/scripts/check-configs.sh),)
+	$(Q)$(CONFIG_SHELL) $(srctree)/arch/$(SRCARCH)/scripts/check-configs.sh $@ $(srctree) $(ARCH)
+endif
 	$< $(silent) --$@ $(Kconfig)
 
 PHONY += oldnoconfig savedefconfig defconfig
-- 
2.3.5

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