This is a note to let you know that I've just added the patch titled
x86/boot: Initialize FPU and X86_FEATURE_ALWAYS even if we don't have CPUID
to the 4.7-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-boot-initialize-fpu-and-x86_feature_always-even-if-we-don-t-have-cpuid.patch
and it can be found in the queue-4.7 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 05fb3c199bb09f5b85de56cc3ede194ac95c5e1f Mon Sep 17 00:00:00 2001
From: Andy Lutomirski <luto@xxxxxxxxxx>
Date: Wed, 28 Sep 2016 16:06:33 -0700
Subject: x86/boot: Initialize FPU and X86_FEATURE_ALWAYS even if we don't have CPUID
From: Andy Lutomirski <luto@xxxxxxxxxx>
commit 05fb3c199bb09f5b85de56cc3ede194ac95c5e1f upstream.
Otherwise arch_task_struct_size == 0 and we die. While we're at it,
set X86_FEATURE_ALWAYS, too.
Reported-by: David Saggiorato <david@xxxxxxxxxxxxxx>
Tested-by: David Saggiorato <david@xxxxxxxxxxxxxx>
Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Dave Hansen <dave@xxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Fixes: aaeb5c01c5b ("x86/fpu, sched: Introduce CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT and use it on x86")
Link: http://lkml.kernel.org/r/8de723afbf0811071185039f9088733188b606c9.1475103911.git.luto@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/common.c | 29 ++++++++++++++---------------
1 file changed, 14 insertions(+), 15 deletions(-)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -804,21 +804,20 @@ static void __init early_identify_cpu(st
identify_cpu_without_cpuid(c);
/* cyrix could have cpuid enabled via c_identify()*/
- if (!have_cpuid_p())
- return;
-
- cpu_detect(c);
- get_cpu_vendor(c);
- get_cpu_cap(c);
-
- if (this_cpu->c_early_init)
- this_cpu->c_early_init(c);
-
- c->cpu_index = 0;
- filter_cpuid_features(c, false);
-
- if (this_cpu->c_bsp_init)
- this_cpu->c_bsp_init(c);
+ if (have_cpuid_p()) {
+ cpu_detect(c);
+ get_cpu_vendor(c);
+ get_cpu_cap(c);
+
+ if (this_cpu->c_early_init)
+ this_cpu->c_early_init(c);
+
+ c->cpu_index = 0;
+ filter_cpuid_features(c, false);
+
+ if (this_cpu->c_bsp_init)
+ this_cpu->c_bsp_init(c);
+ }
setup_force_cpu_cap(X86_FEATURE_ALWAYS);
fpu__init_system(c);
Patches currently in stable-queue which might be from luto@xxxxxxxxxx are
queue-4.7/x86-init-fix-cr4_init_shadow-on-cr4-less-machines.patch
queue-4.7/x86-boot-initialize-fpu-and-x86_feature_always-even-if-we-don-t-have-cpuid.patch
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