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Subject[PATCH 1/3] x86/init: Fix cr4_init_shadow() on CR4-less machines
Date
cr4_init_shadow() will panic on 486-like machines without CR4.  Fix
it using __read_cr4_safe().

Cc: stable@vger.kernel.org
Reported-by: david@saggiorato.net
Fixes: 1e02ce4cccdc ("x86: Store a per-cpu shadow copy of CR4")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
arch/x86/include/asm/tlbflush.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
index 6fa85944af83..dee8a70382ba 100644
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -81,7 +81,7 @@ DECLARE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate);
/* 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. */
--
2.7.4
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