xtensa: extract init_kio

KIO region placement may be specified in the device tree, that's why
it's initialized with the rest of MMU after the early_init_devtree. In
order to support KASAN the MMU must be initialized earlier.
Separate KIO initialization from the rest of MMU initialization.
Reinitialize KIO if its location is specified in the device tree.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

arch/xtensa/mm/mmu.c

@@ -82,6 +82,23 @@ void init_mmu(void)
 	set_itlbcfg_register(0);
 	set_dtlbcfg_register(0);
 #endif
+	init_kio();
+	local_flush_tlb_all();
+
+	/* Set rasid register to a known value. */
+
+	set_rasid_register(ASID_INSERT(ASID_USER_FIRST));
+
+	/* Set PTEVADDR special register to the start of the page
+	 * table, which is in kernel mappable space (ie. not
+	 * statically mapped).  This register's value is undefined on
+	 * reset.
+	 */
+	set_ptevaddr_register(XCHAL_PAGE_TABLE_VADDR);
+}
+
+void init_kio(void)
+{
 #if XCHAL_HAVE_PTP_MMU && XCHAL_HAVE_SPANNING_WAY && defined(CONFIG_OF)
 	/*
 	 * Update the IO area mapping in case xtensa_kio_paddr has changed
@@ -95,17 +112,4 @@ void init_mmu(void)
 	write_itlb_entry(__pte(xtensa_kio_paddr + CA_BYPASS),
 			XCHAL_KIO_BYPASS_VADDR + 6);
 #endif
-
-	local_flush_tlb_all();
-
-	/* Set rasid register to a known value. */
-
-	set_rasid_register(ASID_INSERT(ASID_USER_FIRST));
-
-	/* Set PTEVADDR special register to the start of the page
-	 * table, which is in kernel mappable space (ie. not
-	 * statically mapped).  This register's value is undefined on
-	 * reset.
-	 */
-	set_ptevaddr_register(PGTABLE_START);
 }