4.4-stable review patch. If anyone has any objections, please let me know.
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From: Dave Hansen dave.hansen@linux.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@linux.intel.com Cc: Andy Lutomirski luto@kernel.org Cc: Borislav Petkov bp@alien8.de Cc: Brian Gerst brgerst@gmail.com Cc: Dave Hansen dave@sr71.net Cc: Denys Vlasenko dvlasenk@redhat.com Cc: H. Peter Anvin hpa@zytor.com Cc: Josh Poimboeuf jpoimboe@redhat.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Link: http://lkml.kernel.org/r/20160629200108.92466F6F@viggo.jf.intel.com Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Srivatsa S. Bhat srivatsa@csail.mit.edu Reviewed-by: Matt Helsley (VMware) matt.helsley@gmail.com Reviewed-by: Alexey Makhalov amakhalov@vmware.com Reviewed-by: Bo Gan ganb@vmware.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.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 */