linux-kernel - [PATCH 4.4 35/43] x86/cpufeature: Make sure DISABLED/REQUIRED macros are updated

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Message-Id: <20180716073515.772914193@linuxfoundation.org>
Date:   Mon, 16 Jul 2018 09:36:40 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Dave Hansen <dave.hansen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Borislav Petkov <bp@...en8.de>,
        Brian Gerst <brgerst@...il.com>, Dave Hansen <dave@...1.net>,
        Denys Vlasenko <dvlasenk@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>,
        "Srivatsa S. Bhat" <srivatsa@...il.mit.edu>,
        "Matt Helsley (VMware)" <matt.helsley@...il.com>,
        Alexey Makhalov <amakhalov@...are.com>,
        Bo Gan <ganb@...are.com>
Subject: [PATCH 4.4 35/43] x86/cpufeature: Make sure DISABLED/REQUIRED macros are updated

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

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

From: Dave Hansen <dave.hansen@...ux.intel.com>

commit 1e61f78baf893c7eb49f633d23ccbb420c8f808e upstream

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>
Signed-off-by: Srivatsa S. Bhat <srivatsa@...il.mit.edu>
Reviewed-by: Matt Helsley (VMware) <matt.helsley@...il.com>
Reviewed-by: Alexey Makhalov <amakhalov@...are.com>
Reviewed-by: Bo Gan <ganb@...are.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.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(-)

--- 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[
 	   (((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[
 	   (((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 :	\
--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -59,5 +59,6 @@
 #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 */
--- 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 */