diff --git a/drivers/gpu/arm/mali/Kbuild b/drivers/gpu/arm/mali/Kbuild
index ea4228adf15117..d5e91fcea8ab4c 100755
--- a/drivers/gpu/arm/mali/Kbuild
+++ b/drivers/gpu/arm/mali/Kbuild
@@ -25,7 +25,7 @@ MALI_ENABLE_CPU_CYCLES ?= 0
 # For customer releases the Linux Device Drivers will be provided as ARM proprietary and GPL releases:
 # The ARM proprietary product will only include the license/proprietary directory
 # The GPL product will only include the license/gpl directory
-ifeq ($(wildcard $(src)/linux/license/gpl/*),)
+ifeq ($(wildcard $(srctree)/$(src)/linux/license/gpl/*),)
     ccflags-y += -I$(src)/linux/license/proprietary
     ifeq ($(CONFIG_MALI400_PROFILING),y)
         $(error Profiling is incompatible with non-GPL license)
@@ -57,7 +57,7 @@ ifeq ($(MALI_PLATFORM_FILES),)
 ifeq ($(CONFIG_ARCH_EXYNOS4),y)
 EXTRA_DEFINES += -DMALI_FAKE_PLATFORM_DEVICE=1
 export MALI_PLATFORM=exynos4
-export MALI_PLATFORM_FILES_BUILDIN = $(notdir $(wildcard $(src)/platform/$(MALI_PLATFORM)/*.c))
+export MALI_PLATFORM_FILES_BUILDIN = $(notdir $(wildcard $(srctree)/$(src)/platform/$(MALI_PLATFORM)/*.c))
 export MALI_PLATFORM_FILES_ADD_PREFIX = $(addprefix platform/$(MALI_PLATFORM)/,$(MALI_PLATFORM_FILES_BUILDIN)) 
 endif
 endif
diff --git a/drivers/gpu/arm/ump/Kbuild b/drivers/gpu/arm/ump/Kbuild
index 11b9ab56c99bb2..4437fe65a0ce42 100755
--- a/drivers/gpu/arm/ump/Kbuild
+++ b/drivers/gpu/arm/ump/Kbuild
@@ -13,7 +13,7 @@
 CONFIG ?= default
 
 # Validate selected config
-ifneq ($(shell [ -d $(src)/arch-$(CONFIG) ] && [ -f  $(src)/arch-$(CONFIG)/config.h ] && echo "OK"), OK)
+ifneq ($(shell [ -d $(srctree)/$(src)/arch-$(CONFIG) ] && [ -f  $(srctree)/$(src)/arch-$(CONFIG)/config.h ] && echo "OK"), OK)
 $(warning Current directory is $(src))
 $(error No configuration found for config $(CONFIG). Check that arch-$(CONFIG)/config.h exists)
 else
diff --git a/include/linux/log2.h b/include/linux/log2.h
index fd7ff3d91e6a92..f38fae23bdac52 100644
--- a/include/linux/log2.h
+++ b/include/linux/log2.h
@@ -15,12 +15,6 @@
 #include <linux/types.h>
 #include <linux/bitops.h>
 
-/*
- * deal with unrepresentable constant logarithms
- */
-extern __attribute__((const, noreturn))
-int ____ilog2_NaN(void);
-
 /*
  * non-constant log of base 2 calculators
  * - the arch may override these in asm/bitops.h if they can be implemented
@@ -85,7 +79,7 @@ unsigned long __rounddown_pow_of_two(unsigned long n)
 #define ilog2(n)				\
 (						\
 	__builtin_constant_p(n) ? (		\
-		(n) < 1 ? ____ilog2_NaN() :	\
+		(n) < 2 ? 0 :			\
 		(n) & (1ULL << 63) ? 63 :	\
 		(n) & (1ULL << 62) ? 62 :	\
 		(n) & (1ULL << 61) ? 61 :	\
@@ -148,10 +142,7 @@ unsigned long __rounddown_pow_of_two(unsigned long n)
 		(n) & (1ULL <<  4) ?  4 :	\
 		(n) & (1ULL <<  3) ?  3 :	\
 		(n) & (1ULL <<  2) ?  2 :	\
-		(n) & (1ULL <<  1) ?  1 :	\
-		(n) & (1ULL <<  0) ?  0 :	\
-		____ilog2_NaN()			\
-				   ) :		\
+		1 ) :				\
 	(sizeof(n) <= 4) ?			\
 	__ilog2_u32(n) :			\
 	__ilog2_u64(n)				\