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-rw-r--r--arch/i386/Kconfig37
-rw-r--r--include/asm-i386/page.h4
2 files changed, 39 insertions, 2 deletions
diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
index 4e9e49a..d86c865 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 73296d9..997ca5d 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)