[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>

1 files changed, 20 insertions, 0 deletions

diff --git a/arch/parisc/kernel/firmware.c b/arch/parisc/kernel/firmware.c
index 0596f27340cc..c80c277454f3 100644
--- a/arch/parisc/kernel/firmware.c
+++ b/arch/parisc/kernel/firmware.c
@@ -512,6 +512,26 @@ int pdc_cache_info(struct pdc_cache_info *cache_info)
         return retval;
 }
 
+/**
+ * pdc_spaceid_bits - Return whether Space ID hashing is turned on.
+ * @space_bits: Should be 0, if not, bad mojo!
+ *
+ * Returns information about Space ID hashing.
+ */
+int pdc_spaceid_bits(unsigned long *space_bits)
+{
+	int retval;
+
+	spin_lock_irq(&pdc_lock);
+	pdc_result[0] = 0;
+	retval = mem_pdc_call(PDC_CACHE, PDC_CACHE_RET_SPID, __pa(pdc_result), 0);
+	convert_to_wide(pdc_result);
+	*space_bits = pdc_result[0];
+	spin_unlock_irq(&pdc_lock);
+
+	return retval;
+}
+
 #ifndef CONFIG_PA20
 /**
  * pdc_btlb_info - Return block TLB information.