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authorVivek Goyal <vgoyal@in.ibm.com>2007-01-05 16:36:30 -0800
committerLinus Torvalds <torvalds@woody.osdl.org>2007-01-05 23:55:23 -0800
commitdd0ec16fa6cf2498b831663a543e1b67fce6e155 (patch)
tree6b91a5ff9713c83f6026d1198be98f7ed1e845e6 /arch/i386
parenta75acf850ca80136a4f845cf9a7cd26e7465c1f4 (diff)
[PATCH] i386: Restore CONFIG_PHYSICAL_START option
o Relocatable bzImage support had got rid of CONFIG_PHYSICAL_START option thinking that now this option is not required as people can build a second kernel as relocatable and load it anywhere. So need of compiling the kernel for a custom address was gone. But Magnus uses vmlinux images for second kernel in Xen environment and he wants to continue to use it. o Restoring the CONFIG_PHYSICAL_START option for the time being. I think down the line we can get rid of it. Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/i386')
-rw-r--r--arch/i386/Kconfig41
1 files changed, 41 insertions, 0 deletions
diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
index 0d67a0a1151..0dfee812811 100644
--- a/arch/i386/Kconfig
+++ b/arch/i386/Kconfig
@@ -777,6 +777,47 @@ config CRASH_DUMP
PHYSICAL_START.
For more details see Documentation/kdump/kdump.txt
+config PHYSICAL_START
+ hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
+ default "0x100000"
+ help
+ This gives the physical address where the kernel is loaded.
+
+ If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
+ bzImage will decompress itself to above physical address and
+ run from there. Otherwise, bzImage will run from the address where
+ it has been loaded by the boot loader and will ignore above physical
+ address.
+
+ In normal kdump cases one does not have to set/change this option
+ as now bzImage can be compiled as a completely relocatable image
+ (CONFIG_RELOCATABLE=y) and be used to load and run from a different
+ address. This option is mainly useful for the folks who don't want
+ to use a bzImage for capturing the crash dump and want to use a
+ vmlinux instead. vmlinux is not relocatable hence a kernel needs
+ to be specifically compiled to run from a specific memory area
+ (normally a reserved region) and this option comes handy.
+
+ So if you are using bzImage for capturing the crash dump, leave
+ the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
+ Otherwise if you plan to use vmlinux for capturing the crash dump
+ change this value to start of the reserved region (Typically 16MB
+ 0x1000000). In other words, it can be set based on the "X" value as
+ specified in the "crashkernel=YM@XM" command line boot parameter
+ passed to the panic-ed kernel. Typically this parameter is set as
+ crashkernel=64M@16M. Please take a look at
+ Documentation/kdump/kdump.txt for more details about crash dumps.
+
+ Usage of bzImage for capturing the crash dump is recommended as
+ one does not have to build two kernels. Same kernel can be used
+ as production kernel and capture kernel. Above option should have
+ gone away after relocatable bzImage support is introduced. But it
+ is present because there are users out there who continue to use
+ vmlinux for dump capture. This option should go away down the
+ line.
+
+ Don't change this unless you know what you are doing.
+
config RELOCATABLE
bool "Build a relocatable kernel(EXPERIMENTAL)"
depends on EXPERIMENTAL