Patch "x86/cpuid: Replace set/clear_bit32()" has been added to the 4.14-stable tree

[<gregkh@linuxfoundation.org>]

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

    x86/cpuid: Replace set/clear_bit32()

to the 4.14-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-cpuid-replace-set-clear_bit32.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 06dd688ddda5819025e014b79aea9af6ab475fa2 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Thu, 2 Nov 2017 13:22:35 +0100
Subject: x86/cpuid: Replace set/clear_bit32()

From: Thomas Gleixner <tglx@linutronix.de>

commit 06dd688ddda5819025e014b79aea9af6ab475fa2 upstream.

Peter pointed out that the set/clear_bit32() variants are broken in various
aspects.

Replace them with open coded set/clear_bit() and type cast
cpu_info::x86_capability as it's done in all other places throughout x86.

Fixes: 0b00de857a64 ("x86/cpuid: Add generic table for CPUID dependencies")
Reported-by: Peter Ziljstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/x86/kernel/cpu/cpuid-deps.c |   26 +++++++++++---------------
 1 file changed, 11 insertions(+), 15 deletions(-)

--- a/arch/x86/kernel/cpu/cpuid-deps.c
+++ b/arch/x86/kernel/cpu/cpuid-deps.c
@@ -62,23 +62,19 @@ const static struct cpuid_dep cpuid_deps
 	{}
 };
 
-static inline void __clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int bit)
-{
-	clear_bit32(bit, c->x86_capability);
-}
-
-static inline void __setup_clear_cpu_cap(unsigned int bit)
-{
-	clear_cpu_cap(&boot_cpu_data, bit);
-	set_bit32(bit, cpu_caps_cleared);
-}
-
 static inline void clear_feature(struct cpuinfo_x86 *c, unsigned int feature)
 {
-	if (!c)
-		__setup_clear_cpu_cap(feature);
-	else
-		__clear_cpu_cap(c, feature);
+	/*
+	 * Note: This could use the non atomic __*_bit() variants, but the
+	 * rest of the cpufeature code uses atomics as well, so keep it for
+	 * consistency. Cleanup all of it separately.
+	 */
+	if (!c) {
+		clear_cpu_cap(&boot_cpu_data, feature);
+		set_bit(feature, (unsigned long *)cpu_caps_cleared);
+	} else {
+		clear_bit(feature, (unsigned long *)c->x86_capability);
+	}
 }
 
 /* Take the capabilities and the BUG bits into account */


Patches currently in stable-queue which might be from tglx@linutronix.de are

queue-4.14/x86-asm-remove-unnecessary-n-t-in-front-of-cc_set-from-asm-templates.patch
queue-4.14/x86-cpuid-add-generic-table-for-cpuid-dependencies.patch
queue-4.14/objtool-don-t-report-end-of-section-error-after-an-empty-unwind-hint.patch
queue-4.14/x86-cpufeatures-enable-new-sse-avx-avx512-cpu-features.patch
queue-4.14/x86-cpuid-prevent-out-of-bound-access-in-do_clear_cpu_cap.patch
queue-4.14/x86-cpufeatures-re-tabulate-the-x86_feature-definitions.patch
queue-4.14/x86-cpuid-replace-set-clear_bit32.patch