[PATCH] kexec: x86_64: add CONFIG_PHYSICAL_START

For one kernel to report a crash another kernel has created we need
to have 2 kernels loaded simultaneously in memory.  To accomplish this
the two kernels need to built to run at different physical addresses.

This patch adds the CONFIG_PHYSICAL_START option to the x86_64 kernel
so we can do just that.  You need to know what you are doing and
the ramifications are before changing this value, and most users
won't care so I have made it depend on CONFIG_EMBEDDED

bzImage kernels will work and run at a different address when compiled
with this option but they will still load at 1MB.  If you need a kernel
loaded at a different address as well you need to boot a vmlinux.

Signed-off-by: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 9 insertions, 9 deletions

diff --git a/arch/x86_64/kernel/head.S b/arch/x86_64/kernel/head.S
index 9bd2e7a4b81..8d765aa77a2 100644
--- a/arch/x86_64/kernel/head.S
+++ b/arch/x86_64/kernel/head.S
@@ -248,23 +248,23 @@ ENTRY(_stext)
          */
 .org 0x1000
 ENTRY(init_level4_pgt)
-        .quad   0x0000000000102007              /* -> level3_ident_pgt */
+        .quad   0x0000000000002007 + __PHYSICAL_START   /* -> level3_ident_pgt */
         .fill   255,8,0
-        .quad   0x000000000010a007
+        .quad   0x000000000000a007 + __PHYSICAL_START
         .fill   254,8,0
         /* (2^48-(2*1024*1024*1024))/(2^39) = 511 */
-        .quad   0x0000000000103007              /* -> level3_kernel_pgt */
+        .quad   0x0000000000003007 + __PHYSICAL_START   /* -> level3_kernel_pgt */
 
 .org 0x2000
 ENTRY(level3_ident_pgt)
-        .quad   0x0000000000104007
+        .quad   0x0000000000004007 + __PHYSICAL_START
         .fill   511,8,0
 
 .org 0x3000
 ENTRY(level3_kernel_pgt)
         .fill   510,8,0
         /* (2^48-(2*1024*1024*1024)-((2^39)*511))/(2^30) = 510 */
-        .quad   0x0000000000105007              /* -> level2_kernel_pgt */
+        .quad   0x0000000000005007 + __PHYSICAL_START   /* -> level2_kernel_pgt */
         .fill   1,8,0
 
 .org 0x4000
@@ -337,17 +337,17 @@ ENTRY(empty_bad_pmd_table)
 
 .org 0xa000
 ENTRY(level3_physmem_pgt)
-        .quad   0x0000000000105007              /* -> level2_kernel_pgt (so that __va works even before pagetable_init) */
+        .quad   0x0000000000005007 + __PHYSICAL_START   /* -> level2_kernel_pgt (so that __va works even before pagetable_init) */
 
         .org 0xb000
 #ifdef CONFIG_ACPI_SLEEP
 ENTRY(wakeup_level4_pgt)
-        .quad   0x0000000000102007              /* -> level3_ident_pgt */
+        .quad   0x0000000000002007 + __PHYSICAL_START   /* -> level3_ident_pgt */
         .fill   255,8,0
-        .quad   0x000000000010a007
+        .quad   0x000000000000a007 + __PHYSICAL_START
         .fill   254,8,0
         /* (2^48-(2*1024*1024*1024))/(2^39) = 511 */
-        .quad   0x0000000000103007              /* -> level3_kernel_pgt */
+        .quad   0x0000000000003007 + __PHYSICAL_START   /* -> level3_kernel_pgt */
 #endif
 
         .data