===== arch/ppc64/kernel/head.S 1.20 vs edited =====
--- 1.20/arch/ppc64/kernel/head.S	Tue Jan  6 00:21:31 2004
+++ edited/arch/ppc64/kernel/head.S	Fri Jan 16 11:30:10 2004
@@ -1225,18 +1225,6 @@
 	mulld   r20,r20,r21
 	clrldi  r20,r20,28      /* r20 = vsid */

-	/* Search the SLB for a free entry */
-	li      r22,1
-1:
-	slbmfee	r23,r22
-	rldicl  r23,r23,37,63
-	cmpwi   r23,0
-	beq     4f              /* Found an invalid entry              */
-
-	addi	r22,r22,1
-	cmpldi	r22,64
-	blt	1b
-
 	/* No free entry - just take the next entry, round-robin */
 	/* XXX we should get the number of SLB entries from the naca */
 SLB_NUM_ENTRIES = 64
@@ -1250,6 +1238,12 @@

 	/* r20 = vsid, r22 = entry */

+	/* Check to see if old entry is invalid. If so, no need to slbie */
+	slbmfee	r21,r22
+	rldicl  r23,r21,37,63
+	cmpwi   r23,0
+	beq     4f
+
 	/*
 	 * Never cast out the segment for our kernel stack. Since we
 	 * dont invalidate the ERAT we could have a valid translation
@@ -1269,8 +1263,13 @@
 	cmpd	r21,r23
 	beq-	2b

-4:
-	/* Put together the vsid portion of the entry. */
+	/* Invalidate the old entry */
+	lis	r23,-2049
+	ori	r23,r23,65535
+	and	r21,r21,r23
+	slbie	r21
+
+4:	/* Put together the vsid portion of the entry. */
 	li      r21,0
 	rldimi  r21,r20,12,0
 	ori     r20,r21,1024
@@ -1278,13 +1277,6 @@
 	ori	r20,r20,256    /* map kernel region with large ptes */
 #endif

-	/* Invalidate the old entry */
-	slbmfee	r21,r22
-	lis	r23,-2049
-	ori	r23,r23,65535
-	and	r21,r21,r23
-	slbie	r21
-
 	/* Put together the esid portion of the entry. */
 	mfspr	r21,DAR        /* Get the new esid                     */
 	rldicl  r21,r21,36,28  /* Permits a full 36b of ESID           */