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

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Message-Id: <20171222084625.544783162@linuxfoundation.org>
Date:   Fri, 22 Dec 2017 09:45:18 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Borislav Petkov <bp@...en8.de>,
        Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Borislav Petkov <bp@...e.de>,
        Andy Lutomirski <luto@...nel.org>,
        "Michael S. Tsirkin" <mst@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        ricardo.neri@...el.com, linux-mm@...ck.org,
        Paul Gortmaker <paul.gortmaker@...driver.com>,
        Huang Rui <ray.huang@....com>, Shuah Khan <shuah@...nel.org>,
        linux-arch@...r.kernel.org, Jonathan Corbet <corbet@....net>,
        Jiri Slaby <jslaby@...e.cz>,
        "Ravi V. Shankar" <ravi.v.shankar@...el.com>,
        Denys Vlasenko <dvlasenk@...hat.com>,
        Chris Metcalf <cmetcalf@...lanox.com>,
        Brian Gerst <brgerst@...il.com>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Chen Yucong <slaoub@...il.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Dave Hansen <dave.hansen@...el.com>,
        Andy Lutomirski <luto@...capital.net>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>
Subject: [PATCH 4.14 033/159] x86/boot: Relocate definition of the initial state of CR0

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

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

From: Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>

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@...en8.de>
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Reviewed-by: Borislav Petkov <bp@...e.de>
Reviewed-by: Andy Lutomirski <luto@...nel.org>
Cc: "Michael S. Tsirkin" <mst@...hat.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: ricardo.neri@...el.com
Cc: linux-mm@...ck.org
Cc: Paul Gortmaker <paul.gortmaker@...driver.com>
Cc: Huang Rui <ray.huang@....com>
Cc: Shuah Khan <shuah@...nel.org>
Cc: linux-arch@...r.kernel.org
Cc: Jonathan Corbet <corbet@....net>
Cc: Jiri Slaby <jslaby@...e.cz>
Cc: "Ravi V. Shankar" <ravi.v.shankar@...el.com>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: Chris Metcalf <cmetcalf@...lanox.com>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Chen Yucong <slaoub@...il.com>
Cc: Vlastimil Babka <vbabka@...e.cz>
Cc: Dave Hansen <dave.hansen@...el.com>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Masami Hiramatsu <mhiramat@...nel.org>
Cc: Paolo Bonzini <pbonzini@...hat.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Link: https://lkml.kernel.org/r/1509135945-13762-3-git-send-email-ricardo.neri-calderon@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 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