powerpc/book3e: Use way 3 for linear mapping bolted entry

An erratum on A2 can lead to the bolted entry we insert for the linear
mapping being evicted, to avoid that write the bolted entry to way 3.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/kernel/exceptions-64e.S

@@ -864,8 +864,9 @@ have_hes:
 	 * that will have to be made dependent on whether we are running under
 	 * a hypervisor I suppose.
 	 */
-	ori	r3,r3,MAS0_HES | MAS0_WQ_ALLWAYS
-	mtspr	SPRN_MAS0,r3
+	ori	r11,r3,MAS0_WQ_ALLWAYS
+	oris	r11,r11,MAS0_ESEL(3)@h /* Use way 3: workaround A2 erratum 376 */
+	mtspr	SPRN_MAS0,r11
 	lis	r3,(MAS1_VALID | MAS1_IPROT)@h
 	ori	r3,r3,BOOK3E_PAGESZ_1GB << MAS1_TSIZE_SHIFT
 	mtspr	SPRN_MAS1,r3