[PATCH] RAID6 Altivec fix

This patch fixes a signedness bug with RAID6 for Altivec, and makes the
Altivec code testable in userspace.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 13 insertions, 5 deletions

diff --git a/drivers/md/raid6altivec.uc b/drivers/md/raid6altivec.uc
index 1de8f030eee0..b9afd35b8812 100644
--- a/drivers/md/raid6altivec.uc
+++ b/drivers/md/raid6altivec.uc
@@ -27,16 +27,20 @@
 #ifdef CONFIG_ALTIVEC
 
 #include <altivec.h>
-#include <asm/system.h>
-#include <asm/cputable.h>
+#ifdef __KERNEL__
+# include <asm/system.h>
+# include <asm/cputable.h>
+#endif
 
 /*
- * This is the C data type to use
+ * This is the C data type to use.  We use a vector of
+ * signed char so vec_cmpgt() will generate the right
+ * instruction.
  */
 
-typedef vector unsigned char unative_t;
+typedef vector signed char unative_t;
 
-#define NBYTES(x) ((vector unsigned char) {x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x})
+#define NBYTES(x) ((vector signed char) {x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x})
 #define NSIZE   sizeof(unative_t)
 
 /*
@@ -108,7 +112,11 @@ int raid6_have_altivec(void);
 int raid6_have_altivec(void)
 {
         /* This assumes either all CPUs have Altivec or none does */
+# ifdef __KERNEL__
         return cpu_has_feature(CPU_FTR_ALTIVEC);
+# else
+        return 1;
+# endif
 }
 #endif