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authorMohan Kumar M <mohan@in.ibm.com>2008-10-21 17:38:10 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2008-10-22 15:01:22 +1100
commit54622f10a6aabb8bb2bdacf3dd070046f03dc246 (patch)
tree73eb5ad4eeb7174b8c0ae1904bbe80602c5e295d /arch/powerpc/kernel/machine_kexec.c
parent4792adbac9eb41cea77a45ab76258ea10d411173 (diff)
downloadop-kernel-dev-54622f10a6aabb8bb2bdacf3dd070046f03dc246.zip
op-kernel-dev-54622f10a6aabb8bb2bdacf3dd070046f03dc246.tar.gz
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/kernel/machine_kexec.c')
-rw-r--r--arch/powerpc/kernel/machine_kexec.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/machine_kexec.c b/arch/powerpc/kernel/machine_kexec.c
index aab7688..ac2a21f 100644
--- a/arch/powerpc/kernel/machine_kexec.c
+++ b/arch/powerpc/kernel/machine_kexec.c
@@ -88,11 +88,13 @@ void __init reserve_crashkernel(void)
crash_size = crashk_res.end - crashk_res.start + 1;
+#ifndef CONFIG_RELOCATABLE
if (crashk_res.start != KDUMP_KERNELBASE)
printk("Crash kernel location must be 0x%x\n",
KDUMP_KERNELBASE);
crashk_res.start = KDUMP_KERNELBASE;
+#endif
crash_size = PAGE_ALIGN(crash_size);
crashk_res.end = crashk_res.start + crash_size - 1;
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