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Patch "x86/microcode: Untangle from BLK_DEV_INITRD" has been added to the 4.5-stable tree

PATCH [email protected] 1 participant 1 message Apr 9, 2016

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This is a note to let you know that I've just added the patch titled

x86/microcode: Untangle from BLK_DEV_INITRD

to the 4.5-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
x86-microcode-untangle-from-blk_dev_initrd.patch
and it can be found in the queue-4.5 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 5f9c01aa7c49a2d74474d6d879a797b8badf29e6 Mon Sep 17 00:00:00 2001

From: Borislav Petkov <[email protected]>
Date: Wed, 3 Feb 2016 12:33:29 +0100
Subject: x86/microcode: Untangle from BLK_DEV_INITRD

From: Borislav Petkov <[email protected]>

commit 5f9c01aa7c49a2d74474d6d879a797b8badf29e6 upstream.

Thomas Voegtle reported that doing oldconfig with a .config which has CONFIG_MICROCODE enabled but BLK_DEV_INITRD disabled prevents the microcode loading mechanism from being built.

So untangle it from the BLK_DEV_INITRD dependency so that oldconfig doesn't turn it off and add an explanatory text to its Kconfig help what the supported methods for supplying microcode are.

Reported-by Thomas Voegtle <[email protected]>
Tested-by Thomas Voegtle <[email protected]>
Signed-off-by Borislav Petkov <[email protected]>
Cc Linus Torvalds <[email protected]>
Cc Peter Zijlstra <[email protected]>
Cc Thomas Gleixner <[email protected]>
Link http://lkml.kernel.org/r/[email protected] open here
Signed-off-by Ingo Molnar <[email protected]>
Signed-off-by Greg Kroah-Hartman <[email protected]>
---
 arch/x86/Kconfig                      |   23 ++++++++++++-----------
 arch/x86/include/asm/microcode.h      |   26 ++++++++++++++++++++++++++
 arch/x86/kernel/cpu/microcode/intel.c |   14 ++++----------
 3 files changed, 42 insertions(+), 21 deletions(-)
arch/x86/Kconfig +12 -11
@@ -1160,22 +1160,23 @@ config MICROCODE
 	bool "CPU microcode loading support"
 	default y
 	depends on CPU_SUP_AMD || CPU_SUP_INTEL
-	depends on BLK_DEV_INITRD
 	select FW_LOADER
 	---help---
-
 	  If you say Y here, you will be able to update the microcode on
-	  certain Intel and AMD processors. The Intel support is for the
-	  IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
-	  Xeon etc. The AMD support is for families 0x10 and later. You will
-	  obviously need the actual microcode binary data itself which is not
-	  shipped with the Linux kernel.
+	  Intel and AMD processors. The Intel support is for the IA32 family,
+	  e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
+	  AMD support is for families 0x10 and later. You will obviously need
+	  the actual microcode binary data itself which is not shipped with
+	  the Linux kernel.
 
-	  This option selects the general module only, you need to select
-	  at least one vendor specific module as well.
+	  The preferred method to load microcode from a detached initrd is described
+	  in Documentation/x86/early-microcode.txt. For that you need to enable
+	  CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
+	  initrd for microcode blobs.
 
-	  To compile this driver as a module, choose M here: the module
-	  will be called microcode.
+	  In addition, you can build-in the microcode into the kernel. For that you
+	  need to enable FIRMWARE_IN_KERNEL and add the vendor-supplied microcode
+	  to the CONFIG_EXTRA_FIRMWARE config option.
 
 config MICROCODE_INTEL
 	bool "Intel microcode loading support"
arch/x86/include/asm/microcode.h +26 -0
@@ -3,6 +3,7 @@
 
 #include <asm/cpu.h>
 #include <linux/earlycpio.h>
+#include <linux/initrd.h>
 
 #define native_rdmsr(msr, val1, val2)			\
 do {							\

@@ -143,4 +144,29 @@ static inline void reload_early_microcod
 static inline bool
 get_builtin_firmware(struct cpio_data *cd, const char *name)	{ return false; }
 #endif
+
+static inline unsigned long get_initrd_start(void)
+{
+#ifdef CONFIG_BLK_DEV_INITRD
+	return initrd_start;
+#else
+	return 0;
+#endif
+}
+
+static inline unsigned long get_initrd_start_addr(void)
+{
+#ifdef CONFIG_BLK_DEV_INITRD
+#ifdef CONFIG_X86_32
+	unsigned long *initrd_start_p = (unsigned long *)__pa_nodebug(&initrd_start);
+
+	return (unsigned long)__pa_nodebug(*initrd_start_p);
+#else
+	return get_initrd_start();
+#endif
+#else /* CONFIG_BLK_DEV_INITRD */
+	return 0;
+#endif
+}
+
 #endif /* _ASM_X86_MICROCODE_H */
arch/x86/kernel/cpu/microcode/intel.c +4 -10
@@ -694,7 +694,7 @@ int __init save_microcode_in_initrd_inte
 	if (count == 0)
 		return ret;
 
-	copy_initrd_ptrs(mc_saved, mc_saved_in_initrd, initrd_start, count);
+	copy_initrd_ptrs(mc_saved, mc_saved_in_initrd, get_initrd_start(), count);
 	ret = save_microcode(&mc_saved_data, mc_saved, count);
 	if (ret)
 		pr_err("Cannot save microcode patches from initrd.\n");

@@ -756,20 +756,14 @@ void load_ucode_intel_ap(void)
 	struct mc_saved_data *mc_saved_data_p;
 	struct ucode_cpu_info uci;
 	unsigned long *mc_saved_in_initrd_p;
-	unsigned long initrd_start_addr;
 	enum ucode_state ret;
 #ifdef CONFIG_X86_32
-	unsigned long *initrd_start_p;
 
-	mc_saved_in_initrd_p =
-		(unsigned long *)__pa_nodebug(mc_saved_in_initrd);
+	mc_saved_in_initrd_p = (unsigned long *)__pa_nodebug(mc_saved_in_initrd);
 	mc_saved_data_p = (struct mc_saved_data *)__pa_nodebug(&mc_saved_data);
-	initrd_start_p = (unsigned long *)__pa_nodebug(&initrd_start);
-	initrd_start_addr = (unsigned long)__pa_nodebug(*initrd_start_p);
 #else
-	mc_saved_data_p = &mc_saved_data;
 	mc_saved_in_initrd_p = mc_saved_in_initrd;
-	initrd_start_addr = initrd_start;
+	mc_saved_data_p = &mc_saved_data;
 #endif
 
 	/*

@@ -781,7 +775,7 @@ void load_ucode_intel_ap(void)
 
 	collect_cpu_info_early(&uci);
 	ret = load_microcode(mc_saved_data_p, mc_saved_in_initrd_p,
-			     initrd_start_addr, &uci);
+			     get_initrd_start_addr(), &uci);
 
 	if (ret != UCODE_OK)
 		return;

Patches currently in stable-queue which might be from [email protected] are

queue-4.5/x86-microcode-intel-make-early-loader-look-for-builtin-microcode-too.patch queue-4.5/edac-amd64_edac-shift-wrapping-issue-in-f1x_get_norm_dct_addr.patch queue-4.5/x86-microcode-untangle-from-blk_dev_initrd.patch