microblaze: Highmem support

The first highmem implementation.

Signed-off-by: Michal Simek <monstr@monstr.eu>

1 files changed, 11 insertions, 13 deletions

diff --git a/arch/microblaze/Kconfig b/arch/microblaze/Kconfig
index 3267cc5..86ae278 100644
--- a/arch/microblaze/Kconfig
+++ b/arch/microblaze/Kconfig
@@ -159,20 +159,18 @@ config XILINX_UNCACHED_SHADOW
 	  The feature requires the design to define the RAM memory controller
 	  window to be twice as large as the actual physical memory.
 
-config HIGHMEM_START_BOOL
-	bool "Set high memory pool address"
-	depends on ADVANCED_OPTIONS && HIGHMEM
-	help
-	  This option allows you to set the base address of the kernel virtual
-	  area used to map high memory pages.  This can be useful in
-	  optimizing the layout of kernel virtual memory.
-
-	  Say N here unless you know what you are doing.
-
-config HIGHMEM_START
-	hex "Virtual start address of high memory pool" if HIGHMEM_START_BOOL
+config HIGHMEM
+	bool "High memory support"
 	depends on MMU
-	default "0xfe000000"
+	help
+	  The address space of Microblaze processors is only 4 Gigabytes large
+	  and it has to accommodate user address space, kernel address
+	  space as well as some memory mapped IO. That means that, if you
+	  have a large amount of physical memory and/or IO, not all of the
+	  memory can be "permanently mapped" by the kernel. The physical
+	  memory that is not permanently mapped is called "high memory".
+
+	  If unsure, say n.
 
 config LOWMEM_SIZE_BOOL
 	bool "Set maximum low memory"