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 8eda072e9d7c3429a372e3635dc5851f4a42dee1 upstream
Every time we add a word to our cpu features, we need to add something like this in two places:
(((bit)>>5)==16 && (1UL<<((bit)&31) & REQUIRED_MASK16))
The trick is getting the "16" in this case in both places. I've now screwed this up twice, so as pennance, I've come up with this patch to keep me and other poor souls from doing the same.
I also commented the logic behind the bit manipulation showcased above.
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/20160629200110.1BA8949E@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 | 90 +++++++++++++++++++++----------------- 1 file changed, 50 insertions(+), 40 deletions(-)
--- a/arch/x86/include/asm/cpufeature.h +++ b/arch/x86/include/asm/cpufeature.h @@ -49,48 +49,58 @@ extern const char * const x86_bug_flags[ #define test_cpu_cap(c, bit) \ test_bit(bit, (unsigned long *)((c)->x86_capability))
-#define REQUIRED_MASK_BIT_SET(bit) \ - ( (((bit)>>5)==0 && (1UL<<((bit)&31) & REQUIRED_MASK0 )) || \ - (((bit)>>5)==1 && (1UL<<((bit)&31) & REQUIRED_MASK1 )) || \ - (((bit)>>5)==2 && (1UL<<((bit)&31) & REQUIRED_MASK2 )) || \ - (((bit)>>5)==3 && (1UL<<((bit)&31) & REQUIRED_MASK3 )) || \ - (((bit)>>5)==4 && (1UL<<((bit)&31) & REQUIRED_MASK4 )) || \ - (((bit)>>5)==5 && (1UL<<((bit)&31) & REQUIRED_MASK5 )) || \ - (((bit)>>5)==6 && (1UL<<((bit)&31) & REQUIRED_MASK6 )) || \ - (((bit)>>5)==7 && (1UL<<((bit)&31) & REQUIRED_MASK7 )) || \ - (((bit)>>5)==8 && (1UL<<((bit)&31) & REQUIRED_MASK8 )) || \ - (((bit)>>5)==9 && (1UL<<((bit)&31) & REQUIRED_MASK9 )) || \ - (((bit)>>5)==10 && (1UL<<((bit)&31) & REQUIRED_MASK10)) || \ - (((bit)>>5)==11 && (1UL<<((bit)&31) & REQUIRED_MASK11)) || \ - (((bit)>>5)==12 && (1UL<<((bit)&31) & REQUIRED_MASK12)) || \ - (((bit)>>5)==13 && (1UL<<((bit)&31) & REQUIRED_MASK13)) || \ - (((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)) || \ - REQUIRED_MASK_CHECK || \ +/* + * There are 32 bits/features in each mask word. The high bits + * (selected with (bit>>5) give us the word number and the low 5 + * bits give us the bit/feature number inside the word. + * (1UL<<((bit)&31) gives us a mask for the feature_bit so we can + * see if it is set in the mask word. + */ +#define CHECK_BIT_IN_MASK_WORD(maskname, word, bit) \ + (((bit)>>5)==(word) && (1UL<<((bit)&31) & maskname##word )) + +#define REQUIRED_MASK_BIT_SET(feature_bit) \ + ( CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 0, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 1, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 2, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 3, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 4, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 5, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 6, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 7, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 8, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 9, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 10, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 11, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 12, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 13, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 14, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 15, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 16, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 17, feature_bit) || \ + REQUIRED_MASK_CHECK || \ BUILD_BUG_ON_ZERO(NCAPINTS != 18))
-#define DISABLED_MASK_BIT_SET(bit) \ - ( (((bit)>>5)==0 && (1UL<<((bit)&31) & DISABLED_MASK0 )) || \ - (((bit)>>5)==1 && (1UL<<((bit)&31) & DISABLED_MASK1 )) || \ - (((bit)>>5)==2 && (1UL<<((bit)&31) & DISABLED_MASK2 )) || \ - (((bit)>>5)==3 && (1UL<<((bit)&31) & DISABLED_MASK3 )) || \ - (((bit)>>5)==4 && (1UL<<((bit)&31) & DISABLED_MASK4 )) || \ - (((bit)>>5)==5 && (1UL<<((bit)&31) & DISABLED_MASK5 )) || \ - (((bit)>>5)==6 && (1UL<<((bit)&31) & DISABLED_MASK6 )) || \ - (((bit)>>5)==7 && (1UL<<((bit)&31) & DISABLED_MASK7 )) || \ - (((bit)>>5)==8 && (1UL<<((bit)&31) & DISABLED_MASK8 )) || \ - (((bit)>>5)==9 && (1UL<<((bit)&31) & DISABLED_MASK9 )) || \ - (((bit)>>5)==10 && (1UL<<((bit)&31) & DISABLED_MASK10)) || \ - (((bit)>>5)==11 && (1UL<<((bit)&31) & DISABLED_MASK11)) || \ - (((bit)>>5)==12 && (1UL<<((bit)&31) & DISABLED_MASK12)) || \ - (((bit)>>5)==13 && (1UL<<((bit)&31) & DISABLED_MASK13)) || \ - (((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)) || \ - DISABLED_MASK_CHECK || \ +#define DISABLED_MASK_BIT_SET(feature_bit) \ + ( CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 0, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 1, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 2, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 3, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 4, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 5, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 6, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 7, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 8, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 9, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 10, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 11, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 12, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 13, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 14, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 15, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 16, feature_bit) || \ + CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 17, feature_bit) || \ + DISABLED_MASK_CHECK || \ BUILD_BUG_ON_ZERO(NCAPINTS != 18))
#define cpu_has(c, bit) \