[PATCH] powerpc: Add CONFIG_CRASH_DUMP

This patch adds a Kconfig variable, CONFIG_CRASH_DUMP, which configures the
built kernel for use as a Kdump kernel.

Currently "all" this involves is changing the value of KERNELBASE to 32 MB.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 9 insertions, 1 deletions

diff --git a/include/asm-powerpc/page.h b/include/asm-powerpc/page.h
index 4696bdbcc085..76d7cb4b4ffc 100644
--- a/include/asm-powerpc/page.h
+++ b/include/asm-powerpc/page.h
@@ -51,8 +51,16 @@
  *
  * If you want to test if something's a kernel address, use is_kernel_addr().
  */
+
+#ifdef CONFIG_CRASH_DUMP
+/* Kdump kernel runs at 32 MB, change at your peril. */
+#define PHYSICAL_START  0x2000000
+#else
+#define PHYSICAL_START  0x0
+#endif
+
 #define PAGE_OFFSET     ASM_CONST(CONFIG_KERNEL_START)
-#define KERNELBASE      PAGE_OFFSET
+#define KERNELBASE      (PAGE_OFFSET + PHYSICAL_START)
 
 #ifdef CONFIG_DISCONTIGMEM
 #define page_to_pfn(page)       discontigmem_page_to_pfn(page)