4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Nick Desaulniers <ndesaulni...@google.com>

commit 82cd588052815eb4146f9f7c5347ca5e32c56360 upstream.

The bitmask used to define these values produces overflow, as seen by
this compiler warning:

arch/arm64/kernel/head.S:47:8: warning:
      integer overflow in preprocessor expression
  #elif (PAGE_OFFSET & 0x1fffff) != 0
         ^~~~~~~~~~~
arch/arm64/include/asm/memory.h:52:46: note:
      expanded from macro 'PAGE_OFFSET'
  #define PAGE_OFFSET             (UL(0xffffffffffffffff) << (VA_BITS -
1))
                                      ~~~~~~~~~~~~~~~~~~  ^

It would be preferrable to use GENMASK_ULL() instead, but it's not set
up to be used from assembly (the UL() macro token pastes UL suffixes
when not included in assembly sources).

Suggested-by: Ard Biesheuvel <ard.biesheu...@linaro.org>
Suggested-by: Yury Norov <yno...@caviumnetworks.com>
Suggested-by: Matthias Kaehlcke <m...@chromium.org>
Signed-off-by: Nick Desaulniers <ndesaulni...@google.com>
Signed-off-by: Will Deacon <will.dea...@arm.com>
[natechancellor: KIMAGE_VADDR doesn't exist]
Signed-off-by: Nathan Chancellor <natechancel...@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 arch/arm64/include/asm/memory.h |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -49,8 +49,10 @@
  * and PAGE_OFFSET - it must be within 128MB of the kernel text.
  */
 #define VA_BITS                        (CONFIG_ARM64_VA_BITS)
-#define VA_START               (UL(0xffffffffffffffff) << VA_BITS)
-#define PAGE_OFFSET            (UL(0xffffffffffffffff) << (VA_BITS - 1))
+#define VA_START               (UL(0xffffffffffffffff) - \
+       (UL(1) << VA_BITS) + 1)
+#define PAGE_OFFSET            (UL(0xffffffffffffffff) - \
+       (UL(1) << (VA_BITS - 1)) + 1)
 #define MODULES_END            (PAGE_OFFSET)
 #define MODULES_VADDR          (MODULES_END - SZ_64M)
 #define PCI_IO_END             (MODULES_VADDR - SZ_2M)


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