powerpc: Add support for popcnt instructions

POWER5 added popcntb, and POWER7 added popcntw and popcntd. As a first step
this patch does all the work out of line, but it would be nice to implement
them as inlines with an out of line fallback.

The performance issue with hweight was noticed when disabling SMT on a large
(192 thread) POWER7 box. The patch improves that testcase by about 8%.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 6 insertions, 3 deletions

diff --git a/arch/powerpc/include/asm/cputable.h b/arch/powerpc/include/asm/cputable.h
index f3a1fdd9cf08..f0a211d96923 100644
--- a/arch/powerpc/include/asm/cputable.h
+++ b/arch/powerpc/include/asm/cputable.h
@@ -199,6 +199,8 @@ extern const char *powerpc_base_platform;
 #define CPU_FTR_UNALIGNED_LD_STD        LONG_ASM_CONST(0x0080000000000000)
 #define CPU_FTR_ASYM_SMT                LONG_ASM_CONST(0x0100000000000000)
 #define CPU_FTR_STCX_CHECKS_ADDRESS     LONG_ASM_CONST(0x0200000000000000)
+#define CPU_FTR_POPCNTB                 LONG_ASM_CONST(0x0400000000000000)
+#define CPU_FTR_POPCNTD                 LONG_ASM_CONST(0x0800000000000000)
 
 #ifndef __ASSEMBLY__
 
@@ -403,21 +405,22 @@ extern const char *powerpc_base_platform;
             CPU_FTR_PPCAS_ARCH_V2 | CPU_FTR_CTRL | \
             CPU_FTR_MMCRA | CPU_FTR_SMT | \
             CPU_FTR_COHERENT_ICACHE | CPU_FTR_LOCKLESS_TLBIE | \
-            CPU_FTR_PURR | CPU_FTR_STCX_CHECKS_ADDRESS)
+            CPU_FTR_PURR | CPU_FTR_STCX_CHECKS_ADDRESS | \
+            CPU_FTR_POPCNTB)
 #define CPU_FTRS_POWER6 (CPU_FTR_USE_TB | CPU_FTR_LWSYNC | \
             CPU_FTR_PPCAS_ARCH_V2 | CPU_FTR_CTRL | \
             CPU_FTR_MMCRA | CPU_FTR_SMT | \
             CPU_FTR_COHERENT_ICACHE | CPU_FTR_LOCKLESS_TLBIE | \
             CPU_FTR_PURR | CPU_FTR_SPURR | CPU_FTR_REAL_LE | \
             CPU_FTR_DSCR | CPU_FTR_UNALIGNED_LD_STD | \
-            CPU_FTR_STCX_CHECKS_ADDRESS)
+            CPU_FTR_STCX_CHECKS_ADDRESS | CPU_FTR_POPCNTB)
 #define CPU_FTRS_POWER7 (CPU_FTR_USE_TB | CPU_FTR_LWSYNC | \
             CPU_FTR_PPCAS_ARCH_V2 | CPU_FTR_CTRL | \
             CPU_FTR_MMCRA | CPU_FTR_SMT | \
             CPU_FTR_COHERENT_ICACHE | CPU_FTR_LOCKLESS_TLBIE | \
             CPU_FTR_PURR | CPU_FTR_SPURR | CPU_FTR_REAL_LE | \
             CPU_FTR_DSCR | CPU_FTR_SAO  | CPU_FTR_ASYM_SMT | \
-            CPU_FTR_STCX_CHECKS_ADDRESS)
+            CPU_FTR_STCX_CHECKS_ADDRESS | CPU_FTR_POPCNTB | CPU_FTR_POPCNTD)
 #define CPU_FTRS_CELL   (CPU_FTR_USE_TB | CPU_FTR_LWSYNC | \
             CPU_FTR_PPCAS_ARCH_V2 | CPU_FTR_CTRL | \
             CPU_FTR_ALTIVEC_COMP | CPU_FTR_MMCRA | CPU_FTR_SMT | \