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%3Ba=su...

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