1 files changed, 47 insertions, 9 deletions

diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
index cbde675bc95c..0afec8566e7b 100644
--- a/arch/i386/Kconfig
+++ b/arch/i386/Kconfig
@@ -47,15 +47,6 @@ config DMI
 
 source "init/Kconfig"
 
-config DOUBLEFAULT
-        default y
-        bool "Enable doublefault exception handler" if EMBEDDED
-        help
-          This option allows trapping of rare doublefault exceptions that
-          would otherwise cause a system to silently reboot. Disabling this
-          option saves about 4k and might cause you much additional grey
-          hair.
-
 menu "Processor type and features"
 
 choice
@@ -451,12 +442,50 @@ config HIGHMEM4G
 
 config HIGHMEM64G
         bool "64GB"
+        depends on X86_CMPXCHG64
         help
           Select this if you have a 32-bit processor and more than 4
           gigabytes of physical RAM.
 
 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
@@ -711,6 +740,15 @@ config HOTPLUG_CPU
 
           Say N.
 
+config DOUBLEFAULT
+        default y
+        bool "Enable doublefault exception handler" if EMBEDDED
+        help
+          This option allows trapping of rare doublefault exceptions that
+          would otherwise cause a system to silently reboot. Disabling this
+          option saves about 4k and might cause you much additional grey
+          hair.
+
 endmenu