x86/raid6: correctly check for assembler capabilities

Just like for AVX2 (which simply needs an #if -> #ifdef conversion),
SSSE3 assembler support should be checked for before using it.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Jim Kukunas <james.t.kukunas@linux.intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NeilBrown <neilb@suse.de>

arch/x86/Makefile

@@ -148,6 +148,7 @@ cfi-sections := $(call as-instr,.cfi_sections .debug_frame,-DCONFIG_AS_CFI_SECTI
 
 # does binutils support specific instructions?
 asinstr := $(call as-instr,fxsaveq (%rax),-DCONFIG_AS_FXSAVEQ=1)
+asinstr += $(call as-instr,pshufb %xmm0$(comma)%xmm0,-DCONFIG_AS_SSSE3=1)
 asinstr += $(call as-instr,crc32l %eax$(comma)%eax,-DCONFIG_AS_CRC32=1)
 avx_instr := $(call as-instr,vxorps %ymm0$(comma)%ymm1$(comma)%ymm2,-DCONFIG_AS_AVX=1)
 avx2_instr :=$(call as-instr,vpbroadcastb %xmm0$(comma)%ymm1,-DCONFIG_AS_AVX2=1)

lib/raid6/algos.c

@@ -89,10 +89,10 @@ void (*raid6_datap_recov)(int, size_t, int, void **);
 EXPORT_SYMBOL_GPL(raid6_datap_recov);
 
 const struct raid6_recov_calls *const raid6_recov_algos[] = {
-#if (defined(__i386__) || defined(__x86_64__)) && !defined(__arch_um__)
 #ifdef CONFIG_AS_AVX2
 	&raid6_recov_avx2,
 #endif
+#ifdef CONFIG_AS_SSSE3
 	&raid6_recov_ssse3,
 #endif
 	&raid6_recov_intx1,

lib/raid6/recov_avx2.c

@@ -8,7 +8,7 @@
  * of the License.
  */
 
-#if CONFIG_AS_AVX2
+#ifdef CONFIG_AS_AVX2
 
 #include <linux/raid/pq.h>
 #include "x86.h"

lib/raid6/recov_ssse3.c

@@ -7,6 +7,8 @@
  * of the License.
  */
 
+#ifdef CONFIG_AS_SSSE3
+
 #include <linux/raid/pq.h>
 #include "x86.h"
 
@@ -330,3 +332,7 @@ const struct raid6_recov_calls raid6_recov_ssse3 = {
 #endif
 	.priority = 1,
 };
+
+#else
+#warning "your version of binutils lacks SSSE3 support"
+#endif