powerpc/book3s64/pkeys: Use PVR check instead of cpu feature

We are wrongly using CPU_FTRS_POWER8 to check for P8 support. Instead, we should
use PVR value. Now considering we are using CPU_FTRS_POWER8, that
implies we returned true for P9 with older firmware. Keep the same behavior
by checking for P9 PVR value.

Fixes: cf43d3b2 ("powerpc: Enable pkey subsystem")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200709032946.881753-2-aneesh.kumar@linux.ibm.com

arch/powerpc/mm/book3s64/pkeys.c

@@ -83,13 +83,17 @@ static int pkey_initialize(void)
 	scan_pkey_feature();
 
 	/*
-	 * Let's assume 32 pkeys on P8 bare metal, if its not defined by device
-	 * tree. We make this exception since skiboot forgot to expose this
-	 * property on power8.
+	 * Let's assume 32 pkeys on P8/P9 bare metal, if its not defined by device
+	 * tree. We make this exception since some version of skiboot forgot to
+	 * expose this property on power8/9.
 	 */
-	if (!pkeys_devtree_defined && !firmware_has_feature(FW_FEATURE_LPAR) &&
-			cpu_has_feature(CPU_FTRS_POWER8))
-		pkeys_total = 32;
+	if (!pkeys_devtree_defined && !firmware_has_feature(FW_FEATURE_LPAR)) {
+		unsigned long pvr = mfspr(SPRN_PVR);
+
+		if (PVR_VER(pvr) == PVR_POWER8 || PVR_VER(pvr) == PVR_POWER8E ||
+		    PVR_VER(pvr) == PVR_POWER8NVL || PVR_VER(pvr) == PVR_POWER9)
+			pkeys_total = 32;
+	}
 
 	/*
 	 * Adjust the upper limit, based on the number of bits supported by