MIPS: mm: adjust PKMAP location

Space reserved for PKMap should span from PKMAP_BASE to FIXADDR_START.
For large page sizes this is not the case as eg. for 64k pages the range
currently defined is from 0xfe000000 to 0x102000000(!!) which obviously
isn't right.
Remove the hardcoded location and set the BASE address as an offset from
FIXADDR_START.

Since all PKMAP ptes have to be placed in a contiguous memory, ensure
that this is the case by placing them all in a single page. This is
achieved by aligning the end address to pkmap pages count pages.
Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/15950/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/pgtable-32.h

@@ -19,6 +19,10 @@
 #define __ARCH_USE_5LEVEL_HACK
 #include <asm-generic/pgtable-nopmd.h>
 
+#ifdef CONFIG_HIGHMEM
+#include <asm/highmem.h>
+#endif
+
 extern int temp_tlb_entry;
 
 /*
@@ -62,7 +66,8 @@ extern int add_temporary_entry(unsigned long entrylo0, unsigned long entrylo1,
 
 #define VMALLOC_START	  MAP_BASE
 
-#define PKMAP_BASE		(0xfe000000UL)
+#define PKMAP_END	((FIXADDR_START) & ~((LAST_PKMAP << PAGE_SHIFT)-1))
+#define PKMAP_BASE	(PKMAP_END - PAGE_SIZE * LAST_PKMAP)
 
 #ifdef CONFIG_HIGHMEM
 # define VMALLOC_END	(PKMAP_BASE-2*PAGE_SIZE)