powerpc/44x: No need to mask MSR:CE, ME or DE in _tlbil_va on 440

The handlers for Critical, Machine Check or Debug interrupts
will save and restore MMUCR nowadays, thus we only need to
disable normal interrupts when invalidating TLB entries.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Acked-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/mm/tlb_nohash_low.S

@@ -75,18 +75,19 @@ _GLOBAL(_tlbil_va)
 	mfspr	r5,SPRN_MMUCR
 	rlwimi	r5,r4,0,24,31			/* Set TID */
 
-	/* We have to run the search with interrupts disabled, even critical
-	 * and debug interrupts (in fact the only critical exceptions we have
-	 * are debug and machine check).  Otherwise  an interrupt which causes
-	 * a TLB miss can clobber the MMUCR between the mtspr and the tlbsx. */
+	/* We have to run the search with interrupts disabled, otherwise
+	 * an interrupt which causes a TLB miss can clobber the MMUCR
+	 * between the mtspr and the tlbsx.
+	 *
+	 * Critical and Machine Check interrupts take care of saving
+	 * and restoring MMUCR, so only normal interrupts have to be
+	 * taken care of.
+	 */
 	mfmsr	r4
-	lis	r6,(MSR_EE|MSR_CE|MSR_ME|MSR_DE)@ha
-	addi	r6,r6,(MSR_EE|MSR_CE|MSR_ME|MSR_DE)@l
-	andc	r6,r4,r6
-	mtmsr	r6
+	wrteei	0
 	mtspr	SPRN_MMUCR,r5
 	tlbsx.	r3, 0, r3
-	mtmsr	r4
+	wrtee	r4
 	bne	1f
 	sync
 	/* There are only 64 TLB entries, so r3 < 64,