2 files changed, 39 insertions, 2 deletions

diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
index 4e9e49a55ea8..d86c865a7cd2 100644
--- a/arch/i386/Kconfig
+++ b/arch/i386/Kconfig
@@ -448,6 +448,43 @@ config HIGHMEM64G
 
 endchoice
 
+choice
+        depends on EXPERIMENTAL && !X86_PAE
+        prompt "Memory split"
+        default VMSPLIT_3G
+        help
+          Select the desired split between kernel and user memory.
+
+          If the address range available to the kernel is less than the
+          physical memory installed, the remaining memory will be available
+          as "high memory". Accessing high memory is a little more costly
+          than low memory, as it needs to be mapped into the kernel first.
+          Note that increasing the kernel address space limits the range
+          available to user programs, making the address space there
+          tighter.  Selecting anything other than the default 3G/1G split
+          will also likely make your kernel incompatible with binary-only
+          kernel modules.
+
+          If you are not absolutely sure what you are doing, leave this
+          option alone!
+
+        config VMSPLIT_3G
+                bool "3G/1G user/kernel split"
+        config VMSPLIT_3G_OPT
+                bool "3G/1G user/kernel split (for full 1G low memory)"
+        config VMSPLIT_2G
+                bool "2G/2G user/kernel split"
+        config VMSPLIT_1G
+                bool "1G/3G user/kernel split"
+endchoice
+
+config PAGE_OFFSET
+        hex
+        default 0xB0000000 if VMSPLIT_3G_OPT
+        default 0x78000000 if VMSPLIT_2G
+        default 0x40000000 if VMSPLIT_1G
+        default 0xC0000000
+
 config HIGHMEM
         bool
         depends on HIGHMEM64G || HIGHMEM4G
diff --git a/include/asm-i386/page.h b/include/asm-i386/page.h
index 73296d9924fb..997ca5d17876 100644
--- a/include/asm-i386/page.h
+++ b/include/asm-i386/page.h
@@ -110,10 +110,10 @@ extern int page_is_ram(unsigned long pagenr);
 #endif /* __ASSEMBLY__ */
 
 #ifdef __ASSEMBLY__
-#define __PAGE_OFFSET           (0xC0000000)
+#define __PAGE_OFFSET           CONFIG_PAGE_OFFSET
 #define __PHYSICAL_START        CONFIG_PHYSICAL_START
 #else
-#define __PAGE_OFFSET           (0xC0000000UL)
+#define __PAGE_OFFSET           ((unsigned long)CONFIG_PAGE_OFFSET)
 #define __PHYSICAL_START        ((unsigned long)CONFIG_PHYSICAL_START)
 #endif
 #define __KERNEL_START          (__PAGE_OFFSET + __PHYSICAL_START)