[PARISC] Ensure Space ID hashing is turned off

Check PDC_CACHE to see if spaceid hashing is turned on, and fail to
boot if that is the case.

However, some old machines do not implement the PDC_CACHE_RET_SPID
firmware call, so continue to boot if the call fails because of
PDC_BAD_OPTION (but fail in all other error returns).

Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c
index 851519c..bc7c4a4 100644
--- a/arch/parisc/kernel/cache.c
+++ b/arch/parisc/kernel/cache.c
@@ -236,7 +236,8 @@
 
 void disable_sr_hashing(void)
 {
-	int srhash_type;
+	int srhash_type, retval;
+	unsigned long space_bits;
 
 	switch (boot_cpu_data.cpu_type) {
 	case pcx: /* We shouldn't get this far.  setup.c should prevent it. */
@@ -262,6 +263,13 @@
 	}
 
 	disable_sr_hashing_asm(srhash_type);
+
+	retval = pdc_spaceid_bits(&space_bits);
+	/* If this procedure isn't implemented, don't panic. */
+	if (retval < 0 && retval != PDC_BAD_OPTION)
+		panic("pdc_spaceid_bits call failed.\n");
+	if (space_bits != 0)
+		panic("SpaceID hashing is still on!\n");
 }
 
 void flush_dcache_page(struct page *page)