diff --git a/arch/powerpc/include/asm/kasan.h b/arch/powerpc/include/asm/kasan.h
index d635b96c7ea6..7355ed05e65e 100644
--- a/arch/powerpc/include/asm/kasan.h
+++ b/arch/powerpc/include/asm/kasan.h
@@ -15,11 +15,18 @@
 #ifndef __ASSEMBLY__
 
 #include <asm/page.h>
+#include <linux/sizes.h>
 
 #define KASAN_SHADOW_SCALE_SHIFT	3
 
+#if defined(CONFIG_PPC_BOOK3S_32) && defined(CONFIG_MODULES) && defined(CONFIG_STRICT_KERNEL_RWX)
+#define KASAN_KERN_START	ALIGN_DOWN(PAGE_OFFSET - SZ_256M, SZ_256M)
+#else
+#define KASAN_KERN_START	PAGE_OFFSET
+#endif
+
 #define KASAN_SHADOW_START	(KASAN_SHADOW_OFFSET + \
-				 (PAGE_OFFSET >> KASAN_SHADOW_SCALE_SHIFT))
+				 (KASAN_KERN_START >> KASAN_SHADOW_SCALE_SHIFT))
 
 #define KASAN_SHADOW_OFFSET	ASM_CONST(CONFIG_KASAN_SHADOW_OFFSET)