[PATCH 4.14 033/159] x86/boot: Relocate definition of the initial state of CR0

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ricardo Neri <ricardo.neri-calderon@xxxxxxxxxxxxxxx>

commit b0ce5b8c95c83a7b98c679b117e3d6ae6f97154b upstream.

Both head_32.S and head_64.S utilize the same value to initialize the
control register CR0. Also, other parts of the kernel might want to access
this initial definition (e.g., emulation code for User-Mode Instruction
Prevention uses this state to provide a sane dummy value for CR0 when
emulating the smsw instruction). Thus, relocate this definition to a
header file from which it can be conveniently accessed.

Suggested-by: Borislav Petkov <bp@xxxxxxxxx>
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@xxxxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Borislav Petkov <bp@xxxxxxx>
Reviewed-by: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: "Michael S. Tsirkin" <mst@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: ricardo.neri@xxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Cc: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
Cc: Huang Rui <ray.huang@xxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: linux-arch@xxxxxxxxxxxxxxx
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Jiri Slaby <jslaby@xxxxxxx>
Cc: "Ravi V. Shankar" <ravi.v.shankar@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: Chris Metcalf <cmetcalf@xxxxxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Chen Yucong <slaoub@xxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/1509135945-13762-3-git-send-email-ricardo.neri-calderon@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/x86/include/uapi/asm/processor-flags.h |    3 +++
 arch/x86/kernel/head_32.S                   |    3 ---
 arch/x86/kernel/head_64.S                   |    3 ---
 3 files changed, 3 insertions(+), 6 deletions(-)

--- a/arch/x86/include/uapi/asm/processor-flags.h
+++ b/arch/x86/include/uapi/asm/processor-flags.h
@@ -152,5 +152,8 @@
 #define CX86_ARR_BASE	0xc4
 #define CX86_RCR_BASE	0xdc
 
+#define CR0_STATE	(X86_CR0_PE | X86_CR0_MP | X86_CR0_ET | \
+			 X86_CR0_NE | X86_CR0_WP | X86_CR0_AM | \
+			 X86_CR0_PG)
 
 #endif /* _UAPI_ASM_X86_PROCESSOR_FLAGS_H */
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -212,9 +212,6 @@ ENTRY(startup_32_smp)
 #endif
 
 .Ldefault_entry:
-#define CR0_STATE	(X86_CR0_PE | X86_CR0_MP | X86_CR0_ET | \
-			 X86_CR0_NE | X86_CR0_WP | X86_CR0_AM | \
-			 X86_CR0_PG)
 	movl $(CR0_STATE & ~X86_CR0_PG),%eax
 	movl %eax,%cr0
 
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -154,9 +154,6 @@ ENTRY(secondary_startup_64)
 1:	wrmsr				/* Make changes effective */
 
 	/* Setup cr0 */
-#define CR0_STATE	(X86_CR0_PE | X86_CR0_MP | X86_CR0_ET | \
-			 X86_CR0_NE | X86_CR0_WP | X86_CR0_AM | \
-			 X86_CR0_PG)
 	movl	$CR0_STATE, %eax
 	/* Make changes effective */
 	movq	%rax, %cr0