[kvm-unit-tests v2 05/10] powerpc: Indirect SPR accessor functions

[Nicholas Piggin]

Make overly-clever SPR accessor functions that allow a non-constant
SPR number to be specified. This will be used to restructure test
in the next change.

Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
---
 powerpc/sprs.c | 63 ++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 54 insertions(+), 9 deletions(-)

diff --git a/powerpc/sprs.c b/powerpc/sprs.c
index 6ee6dba..db341a9 100644
--- a/powerpc/sprs.c
+++ b/powerpc/sprs.c
@@ -28,21 +28,66 @@
 #include <asm/processor.h>
 #include <asm/barrier.h>
 
-#define mfspr(nr) ({ \
-	uint64_t ret; \
-	asm volatile("mfspr %0,%1" : "=r"(ret) : "i"(nr)); \
-	ret; \
-})
+/* "Indirect" mfspr/mtspr which accept a non-constant spr number */
+static uint64_t mfspr(unsigned spr)
+{
+	uint64_t tmp;
+	uint64_t ret;
+
+	asm volatile(
+"	bcl	20, 31, 1f		\n"
+"1:	mflr	%0			\n"
+"	addi	%0, %0, (2f-1b)		\n"
+"	add	%0, %0, %2		\n"
+"	mtctr	%0			\n"
+"	bctr				\n"
+"2:					\n"
+".LSPR=0				\n"
+".rept 1024				\n"
+"	mfspr	%1, .LSPR		\n"
+"	b	3f			\n"
+"	.LSPR=.LSPR+1			\n"
+".endr					\n"
+"3:					\n"
+	: "=&r"(tmp),
+	  "=r"(ret)
+	: "r"(spr*8) /* 8 bytes per 'mfspr ; b' block */
+	: "lr", "ctr");
+
+	return ret;
+}
 
-#define mtspr(nr, val) \
-	asm volatile("mtspr %0,%1" : : "i"(nr), "r"(val))
+static void mtspr(unsigned spr, uint64_t val)
+{
+	uint64_t tmp;
+
+	asm volatile(
+"	bcl	20, 31, 1f		\n"
+"1:	mflr	%0			\n"
+"	addi	%0, %0, (2f-1b)		\n"
+"	add	%0, %0, %2		\n"
+"	mtctr	%0			\n"
+"	bctr				\n"
+"2:					\n"
+".LSPR=0				\n"
+".rept 1024				\n"
+"	mtspr	.LSPR, %1		\n"
+"	b	3f			\n"
+"	.LSPR=.LSPR+1			\n"
+".endr					\n"
+"3:					\n"
+	: "=&r"(tmp)
+	: "r"(val),
+	  "r"(spr*8) /* 8 bytes per 'mfspr ; b' block */
+	: "lr", "ctr", "xer");
+}
 
 uint64_t before[1024], after[1024];
 
 /* Common SPRs for all PowerPC CPUs */
 static void set_sprs_common(uint64_t val)
 {
-	mtspr(9, val);		/* CTR */
+	// mtspr(9, val);	/* CTR */ /* Used by mfspr/mtspr */
 	// mtspr(273, val);	/* SPRG1 */  /* Used by our exception handler */
 	mtspr(274, val);	/* SPRG2 */
 	mtspr(275, val);	/* SPRG3 */
@@ -156,7 +201,7 @@ static void set_sprs(uint64_t val)
 
 static void get_sprs_common(uint64_t *v)
 {
-	v[9] = mfspr(9);	/* CTR */
+	v[9] = mfspr(9);	/* CTR */ /* Used by mfspr/mtspr */
 	// v[273] = mfspr(273);	/* SPRG1 */ /* Used by our exception handler */
 	v[274] = mfspr(274);	/* SPRG2 */
 	v[275] = mfspr(275);	/* SPRG3 */
-- 
2.37.2