parisc: BTLB: Clear possibly existing BTLB entries

Call PDC to remove all existing BTLB entries (which may exist from
some previous operating system runs) before switching to virtual mode.

Signed-off-by: Helge Deller <deller@gmx.de>

Author: hdeller

arch/parisc/kernel/head.S

@@ -180,10 +180,10 @@ $pgt_fill_loop:
 	std		%dp,0x18(%r10)
 #endif
 
-#ifdef CONFIG_64BIT
-	/* Get PDCE_PROC for monarch CPU. */
 #define MEM_PDC_LO 0x388
 #define MEM_PDC_HI 0x35C
+#ifdef CONFIG_64BIT
+	/* Get PDCE_PROC for monarch CPU. */
 	ldw             MEM_PDC_LO(%r0),%r3
 	ldw             MEM_PDC_HI(%r0),%r10
 	depd            %r10, 31, 32, %r3        /* move to upper word */
@@ -269,7 +269,17 @@ stext_pdc_ret:
 	tovirt_r1	%r6
 	mtctl		%r6,%cr30		/* restore task thread info */
 #endif
-	
+
+#ifndef CONFIG_64BIT
+	/* clear all BTLBs */
+	ldi		PDC_BLOCK_TLB,%arg0
+	load32          PA(stext_pdc_btlb_ret), %rp
+	ldw             MEM_PDC_LO(%r0),%r3
+	bv              (%r3)
+	ldi		PDC_BTLB_PURGE_ALL,%arg1
+stext_pdc_btlb_ret:
+#endif
+
 	/* PARANOID: clear user scratch/user space SR's */
 	mtsp	%r0,%sr0
 	mtsp	%r0,%sr1