This is a note to let you know that I've just added the patch titled
x86/init: Fix cr4_init_shadow() on CR4-less machines
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-init-fix-cr4_init_shadow-on-cr4-less-machines.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 e1bfc11c5a6f40222a698a818dc269113245820e Mon Sep 17 00:00:00 2001
From: Andy Lutomirski <luto@xxxxxxxxxx>
Date: Wed, 28 Sep 2016 12:34:14 -0700
Subject: x86/init: Fix cr4_init_shadow() on CR4-less machines
From: Andy Lutomirski <luto@xxxxxxxxxx>
commit e1bfc11c5a6f40222a698a818dc269113245820e upstream.
cr4_init_shadow() will panic on 486-like machines without CR4. Fix
it using __read_cr4_safe().
Reported-by: david@xxxxxxxxxxxxxx
Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
Reviewed-by: Borislav Petkov <bp@xxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
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: 1e02ce4cccdc ("x86: Store a per-cpu shadow copy of CR4")
Link: http://lkml.kernel.org/r/43a20f81fb504013bf613913dc25574b45336a61.1475091074.git.luto@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/tlbflush.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -81,7 +81,7 @@ DECLARE_PER_CPU_SHARED_ALIGNED(struct tl
/* Initialize cr4 shadow for this CPU. */
static inline void cr4_init_shadow(void)
{
- this_cpu_write(cpu_tlbstate.cr4, __read_cr4());
+ this_cpu_write(cpu_tlbstate.cr4, __read_cr4_safe());
}
/* Set in this cpu's CR4. */
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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