selftests/powerpc/64: Test all paths through copy routines

The hand-coded assembler 64-bit copy routines include feature sections
that select one code path or another depending on which CPU we are
executing on.  The self-tests for these copy routines end up testing
just one path.  This adds a mechanism for selecting any desired code
path at compile time, and makes 2 or 3 versions of each test, each
using a different code path, so as to cover all the possible paths.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
[mpe: Add -mcpu=power4 to CFLAGS for older compilers]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/lib/memcpy_power7.S

@@ -19,7 +19,10 @@
  */
 #include <asm/ppc_asm.h>
 
-_GLOBAL(memcpy_power7)
+#ifndef SELFTEST_CASE
+/* 0 == don't use VMX, 1 == use VMX */
+#define SELFTEST_CASE	0
+#endif
 
 #ifdef __BIG_ENDIAN__
 #define LVS(VRT,RA,RB)		lvsl	VRT,RA,RB
@@ -29,20 +32,17 @@ _GLOBAL(memcpy_power7)
 #define VPERM(VRT,VRA,VRB,VRC)	vperm	VRT,VRB,VRA,VRC
 #endif
 
-#ifdef CONFIG_ALTIVEC
+_GLOBAL(memcpy_power7)
 	cmpldi	r5,16
 	cmpldi	cr1,r5,4096
-
 	std	r3,-STACKFRAMESIZE+STK_REG(R31)(r1)
-
 	blt	.Lshort_copy
-	bgt	cr1,.Lvmx_copy
-#else
-	cmpldi	r5,16
 
-	std	r3,-STACKFRAMESIZE+STK_REG(R31)(r1)
-
-	blt	.Lshort_copy
+#ifdef CONFIG_ALTIVEC
+test_feature = SELFTEST_CASE
+BEGIN_FTR_SECTION
+	bgt	cr1, .Lvmx_copy
+END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
 #endif
 
 .Lnonvmx_copy:
@@ -223,8 +223,8 @@ _GLOBAL(memcpy_power7)
 	addi	r1,r1,STACKFRAMESIZE
 	b	.Lnonvmx_copy
 
-#ifdef CONFIG_ALTIVEC
 .Lvmx_copy:
+#ifdef CONFIG_ALTIVEC
 	mflr	r0
 	std	r4,-STACKFRAMESIZE+STK_REG(R30)(r1)
 	std	r5,-STACKFRAMESIZE+STK_REG(R29)(r1)