linux-kernel - [tip:x86/mm] x86/cpufeatures, x86/fault: Mark SMAP as disabled when configured out

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Message-ID: <tip-dae0a10593007d049ea71601357ac41d4f247ee9@git.kernel.org>
Date:   Tue, 20 Nov 2018 00:15:03 -0800
From:   tip-bot for Andy Lutomirski <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, brgerst@...il.com, hpa@...or.com,
        tglx@...utronix.de, dave.hansen@...ux.intel.com,
        luto@...capital.net, yu-cheng.yu@...el.com, luto@...nel.org,
        riel@...riel.com, torvalds@...ux-foundation.org,
        dvlasenk@...hat.com, bp@...en8.de, peterz@...radead.org,
        mingo@...nel.org
Subject: [tip:x86/mm] x86/cpufeatures, x86/fault: Mark SMAP as disabled when
 configured out

Commit-ID:  dae0a10593007d049ea71601357ac41d4f247ee9
Gitweb:     https://git.kernel.org/tip/dae0a10593007d049ea71601357ac41d4f247ee9
Author:     Andy Lutomirski <luto@...nel.org>
AuthorDate: Mon, 19 Nov 2018 14:45:27 -0800
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Tue, 20 Nov 2018 08:44:28 +0100

x86/cpufeatures, x86/fault: Mark SMAP as disabled when configured out

Add X86_FEATURE_SMAP to the disabled features mask as appropriate
and use cpu_feature_enabled() in the fault code.  This lets us get
rid of a redundant IS_ENABLED(CONFIG_X86_SMAP).

Signed-off-by: Andy Lutomirski <luto@...nel.org>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Rik van Riel <riel@...riel.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@...el.com>
Link: http://lkml.kernel.org/r/fe93332eded3d702f0b0b4cf83928d6830739ba3.1542667307.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/include/asm/disabled-features.h | 8 +++++++-
 arch/x86/mm/fault.c                      | 5 +----
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
index 33833d1909af..a5ea841cc6d2 100644
--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -16,6 +16,12 @@
 # define DISABLE_MPX	(1<<(X86_FEATURE_MPX & 31))
 #endif
 
+#ifdef CONFIG_X86_SMAP
+# define DISABLE_SMAP	0
+#else
+# define DISABLE_SMAP	(1<<(X86_FEATURE_SMAP & 31))
+#endif
+
 #ifdef CONFIG_X86_INTEL_UMIP
 # define DISABLE_UMIP	0
 #else
@@ -68,7 +74,7 @@
 #define DISABLED_MASK6	0
 #define DISABLED_MASK7	(DISABLE_PTI)
 #define DISABLED_MASK8	0
-#define DISABLED_MASK9	(DISABLE_MPX)
+#define DISABLED_MASK9	(DISABLE_MPX|DISABLE_SMAP)
 #define DISABLED_MASK10	0
 #define DISABLED_MASK11	0
 #define DISABLED_MASK12	0
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 8624cb7d8d65..39e39cd42097 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1150,10 +1150,7 @@ static int fault_in_kernel_space(unsigned long address)
 
 static inline bool smap_violation(int error_code, struct pt_regs *regs)
 {
-	if (!IS_ENABLED(CONFIG_X86_SMAP))
-		return false;
-
-	if (!static_cpu_has(X86_FEATURE_SMAP))
+	if (!cpu_feature_enabled(X86_FEATURE_SMAP))
 		return false;
 
 	if (error_code & X86_PF_USER)