[PATCH 5.4 35/51] x86/speculation: Use DECLARE_PER_CPU for x86_spec_ctrl_current

From: Greg Kroah-Hartman
Date: Wed Oct 05 2022 - 07:36:13 EST

From: Nathan Chancellor <nathan@xxxxxxxxxx>

commit db886979683a8360ced9b24ab1125ad0c4d2cf76 upstream.

Clang warns:

arch/x86/kernel/cpu/bugs.c:58:21: error: section attribute is specified on redeclared variable [-Werror,-Wsection]
DEFINE_PER_CPU(u64, x86_spec_ctrl_current);
arch/x86/include/asm/nospec-branch.h:283:12: note: previous declaration is here
extern u64 x86_spec_ctrl_current;
1 error generated.

The declaration should be using DECLARE_PER_CPU instead so all
attributes stay in sync.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: fc02735b14ff ("KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS")
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
arch/x86/include/asm/nospec-branch.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -11,6 +11,7 @@
#include <asm/cpufeatures.h>
#include <asm/msr-index.h>
#include <asm/unwind_hints.h>
+#include <asm/percpu.h>

* This should be used immediately before a retpoline alternative. It tells
@@ -296,7 +297,7 @@ static inline void indirect_branch_predi

/* The Intel SPEC CTRL MSR base value cache */
extern u64 x86_spec_ctrl_base;
-extern u64 x86_spec_ctrl_current;
+DECLARE_PER_CPU(u64, x86_spec_ctrl_current);
extern void write_spec_ctrl_current(u64 val, bool force);
extern u64 spec_ctrl_current(void);