Add AltiVec RAID-Z

Implements the RAID-Z function using AltiVec SIMD.
This is basically the NEON code translated to AltiVec.

Note that the 'fletcher' algorithm requires 64-bits
operations, and the initial implementations of AltiVec
(PPC74xx a.k.a. G4, PPC970 a.k.a. G5) only has up to
32-bits operations, so no 'fletcher'.

Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Romain Dolbeau <[email protected]>
Closes #9539 

1 files changed, 40 insertions, 0 deletions

diff --git a/lib/libspl/include/sys/simd.h b/lib/libspl/include/sys/simd.h
index b25e476a3..32864e153 100644
--- a/lib/libspl/include/sys/simd.h
+++ b/lib/libspl/include/sys/simd.h
@@ -437,6 +437,46 @@ zfs_avx512vbmi_available(void)
 #define	kfpu_begin()		do {} while (0)
 #define	kfpu_end()		do {} while (0)
 
+#elif defined(__powerpc__)
+
+#define	kfpu_allowed()		1
+#define	kfpu_initialize(tsk)	do {} while (0)
+#define	kfpu_begin()		do {} while (0)
+#define	kfpu_end()		do {} while (0)
+
+/*
+ * Check if AltiVec instruction set is available
+ * No easy way beyond 'altivec works' :-(
+ */
+#include <signal.h>
+#include <setjmp.h>
+
+#ifdef __ALTIVEC__
+static jmp_buf env;
+static void sigillhandler(int x)
+{
+	longjmp(env, 1);
+}
+#endif
+
+static inline boolean_t
+zfs_altivec_available(void)
+{
+	boolean_t has_altivec = B_FALSE;
+#ifdef __ALTIVEC__
+	sighandler_t savesig;
+	savesig = signal(SIGILL, sigillhandler);
+	if (setjmp(env)) {
+		signal(SIGILL, savesig);
+		has_altivec = B_FALSE;
+	} else {
+		__asm__ __volatile__("vor 0,0,0\n" : : : "v0");
+		signal(SIGILL, savesig);
+		has_altivec = B_TRUE;
+	}
+#endif
+	return (has_altivec);
+}
 #else
 
 #define	kfpu_allowed()		0