linux-kernel - [tip:x86/cpu] x86/cpufeature: Make sure DISABLED/REQUIRED macros are updated

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Date:	Thu, 30 Jun 2016 14:34:51 -0700
From:	tip-bot for Dave Hansen <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	hpa@...or.com, dave.hansen@...ux.intel.com,
	linux-kernel@...r.kernel.org, dvlasenk@...hat.com,
	torvalds@...ux-foundation.org, jpoimboe@...hat.com,
	luto@...nel.org, peterz@...radead.org, brgerst@...il.com,
	mingo@...nel.org, dave@...1.net, bp@...en8.de, tglx@...utronix.de
Subject: [tip:x86/cpu] x86/cpufeature: Make sure DISABLED/REQUIRED macros
 are updated

Commit-ID:  1e61f78baf893c7eb49f633d23ccbb420c8f808e
Gitweb:     http://git.kernel.org/tip/1e61f78baf893c7eb49f633d23ccbb420c8f808e
Author:     Dave Hansen <dave.hansen@...ux.intel.com>
AuthorDate: Wed, 29 Jun 2016 13:01:08 -0700
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Thu, 30 Jun 2016 09:11:32 +0200

x86/cpufeature: Make sure DISABLED/REQUIRED macros are updated

x86 has two macros which allow us to evaluate some CPUID-based
features at compile time:

	REQUIRED_MASK_BIT_SET()
	DISABLED_MASK_BIT_SET()

They're both defined by having the compiler check the bit
argument against some constant masks of features.

But, when adding new CPUID leaves, we need to check new words
for these macros.  So make sure that those macros and the
REQUIRED_MASK* and DISABLED_MASK* get updated when necessary.

This looks kinda silly to have an open-coded value ("18" in
this case) open-coded in 5 places in the code.  But, we really do
need 5 places updated when NCAPINTS gets bumped, so now we just
force the issue.

Signed-off-by: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Dave Hansen <dave@...1.net>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Link: http://lkml.kernel.org/r/20160629200108.92466F6F@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/include/asm/cpufeature.h        | 8 ++++++--
 arch/x86/include/asm/disabled-features.h | 1 +
 arch/x86/include/asm/required-features.h | 1 +
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index ec81004..7b20720 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -67,7 +67,9 @@ extern const char * const x86_bug_flags[NBUGINTS*32];
 	   (((bit)>>5)==14 && (1UL<<((bit)&31) & REQUIRED_MASK14)) ||	\
 	   (((bit)>>5)==15 && (1UL<<((bit)&31) & REQUIRED_MASK15)) ||	\
 	   (((bit)>>5)==16 && (1UL<<((bit)&31) & REQUIRED_MASK16)) ||	\
-	   (((bit)>>5)==17 && (1UL<<((bit)&31) & REQUIRED_MASK17)))
+	   (((bit)>>5)==17 && (1UL<<((bit)&31) & REQUIRED_MASK17)) ||	\
+	   REQUIRED_MASK_CHECK					   ||	\
+	   BUILD_BUG_ON_ZERO(NCAPINTS != 18))
 
 #define DISABLED_MASK_BIT_SET(bit)					\
 	 ( (((bit)>>5)==0  && (1UL<<((bit)&31) & DISABLED_MASK0 )) ||	\
@@ -87,7 +89,9 @@ extern const char * const x86_bug_flags[NBUGINTS*32];
 	   (((bit)>>5)==14 && (1UL<<((bit)&31) & DISABLED_MASK14)) ||	\
 	   (((bit)>>5)==15 && (1UL<<((bit)&31) & DISABLED_MASK15)) ||	\
 	   (((bit)>>5)==16 && (1UL<<((bit)&31) & DISABLED_MASK16)) ||	\
-	   (((bit)>>5)==17 && (1UL<<((bit)&31) & DISABLED_MASK17)))
+	   (((bit)>>5)==17 && (1UL<<((bit)&31) & DISABLED_MASK17)) ||	\
+	   DISABLED_MASK_CHECK					   ||	\
+	   BUILD_BUG_ON_ZERO(NCAPINTS != 18))
 
 #define cpu_has(c, bit)							\
 	(__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 :	\
diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
index 5627f8c..85599ad 100644
--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -57,5 +57,6 @@
 #define DISABLED_MASK15	0
 #define DISABLED_MASK16	(DISABLE_PKU|DISABLE_OSPKE)
 #define DISABLED_MASK17	0
+#define DISABLED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 18)
 
 #endif /* _ASM_X86_DISABLED_FEATURES_H */
diff --git a/arch/x86/include/asm/required-features.h b/arch/x86/include/asm/required-features.h
index fad4277..fac9a5c 100644
--- a/arch/x86/include/asm/required-features.h
+++ b/arch/x86/include/asm/required-features.h
@@ -100,5 +100,6 @@
 #define REQUIRED_MASK15	0
 #define REQUIRED_MASK16	0
 #define REQUIRED_MASK17	0
+#define REQUIRED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 18)
 
 #endif /* _ASM_X86_REQUIRED_FEATURES_H */