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authorMohan Kumar M <mohan@in.ibm.com>2008-10-21 21:38:10 +0400
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2008-10-22 08:01:22 +0400
commit54622f10a6aabb8bb2bdacf3dd070046f03dc246 (patch)
tree73eb5ad4eeb7174b8c0ae1904bbe80602c5e295d /arch/powerpc/Kconfig
parent4792adbac9eb41cea77a45ab76258ea10d411173 (diff)
downloadlinux-54622f10a6aabb8bb2bdacf3dd070046f03dc246.tar.xz
powerpc: Support for relocatable kdump kernel
This adds relocatable kernel support for kdump. With this one can use the same regular kernel to capture the kdump. A signature (0xfeed1234) is passed in r6 from panic code to the next kernel through kexec_sequence and purgatory code. The signature is used to differentiate between kdump kernel and non-kdump kernels. The purgatory code compares the signature and sets the __kdump_flag in head_64.S. During the boot up, kernel code checks __kdump_flag and if it is set, the kernel will behave as relocatable kdump kernel. This kernel will boot at the address where it was loaded by kexec-tools ie. at the address reserved through crashkernel boot parameter. CONFIG_CRASH_DUMP depends on CONFIG_RELOCATABLE option to build kdump kernel as relocatable. So the same kernel can be used as production and kdump kernel. This patch incorporates the changes suggested by Paul Mackerras to avoid GOT use and to avoid two copies of the code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Mohan Kumar M <mohan@in.ibm.com> Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/Kconfig')
-rw-r--r--arch/powerpc/Kconfig10
1 files changed, 3 insertions, 7 deletions
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 369d93e7377c..5b1527883fcb 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -323,13 +323,11 @@ config KEXEC
config CRASH_DUMP
bool "Build a kdump crash kernel"
- depends on PPC_MULTIPLATFORM && PPC64
+ depends on PPC_MULTIPLATFORM && PPC64 && RELOCATABLE
help
Build a kernel suitable for use as a kdump capture kernel.
- The kernel will be linked at a different address than normal, and
- so can only be used for Kdump.
-
- Don't change this unless you know what you are doing.
+ The same kernel binary can be used as production kernel and dump
+ capture kernel.
config PHYP_DUMP
bool "Hypervisor-assisted dump (EXPERIMENTAL)"
@@ -829,11 +827,9 @@ config PAGE_OFFSET
default "0xc000000000000000"
config KERNEL_START
hex
- default "0xc000000002000000" if CRASH_DUMP
default "0xc000000000000000"
config PHYSICAL_START
hex
- default "0x02000000" if CRASH_DUMP
default "0x00000000"
endif