[PATCH] kexec: x86: add CONFIG_PYSICAL_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 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, 11 insertions, 0 deletions

diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
index 961ab20032f5..31567f4d333a 100644
--- a/arch/i386/Kconfig
+++ b/arch/i386/Kconfig
@@ -942,6 +942,17 @@ config SECCOMP
 
 source kernel/Kconfig.hz
 
+config PHYSICAL_START
+        hex "Physical address where the kernel is loaded" if EMBEDDED
+        default "0x100000"
+        help
+          This gives the physical address where the kernel is loaded.
+          Primarily used in the case of kexec on panic where the
+          fail safe kernel needs to run at a different address than
+          the panic-ed kernel.
+
+          Don't change this unless you know what you are doing.
+
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