[PATCH AUTOSEL for 4.9 224/281] MIPS: mm: adjust PKMAP location

[Sasha Levin]

From: Marcin Nowakowski <marcin.nowakowski@xxxxxxxxxx>

[ Upstream commit c56e7a4c3e77f6fbd9b55c06c14eda65aae58958 ]

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@xxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Patchwork: https://patchwork.linux-mips.org/patch/15950/
Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
---
 arch/mips/include/asm/pgtable-32.h | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/mips/include/asm/pgtable-32.h b/arch/mips/include/asm/pgtable-32.h
index d21f3da7bdb6..c0be540e83cb 100644
--- a/arch/mips/include/asm/pgtable-32.h
+++ b/arch/mips/include/asm/pgtable-32.h
@@ -18,6 +18,10 @@
 
 #include <asm-generic/pgtable-nopmd.h>
 
+#ifdef CONFIG_HIGHMEM
+#include <asm/highmem.h>
+#endif
+
 extern int temp_tlb_entry;
 
 /*
@@ -61,7 +65,8 @@ 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)
-- 
2.14.1