Relocatable kdump kernel support in kexec-tools
This patch adds relocatable kernel support for kdump in the kexec-tools
code. A signature (0xfeed1234) is passed in r6 from panic code to the
purgatory code through kexec_sequence function. The signature is used to
differentiate between relocatable kdump kernel and non-kdump kernels.
The purgatory code compares the signature and sets the __kdump_flag in
head_64.S by using the offset with respect to next kernel load address.
During the boot up, kernel code checks __kdump_flag and if it is set, the
kernel will behave as relocatable kdump kernel.
Signed-off-by: Mohan Kumar M <[EMAIL PROTECTED]>
---
diff --git a/purgatory/arch/ppc64/v2wrap.S b/purgatory/arch/ppc64/v2wrap.S
index b3563de..f69dad2 100644
--- a/purgatory/arch/ppc64/v2wrap.S
+++ b/purgatory/arch/ppc64/v2wrap.S
@@ -45,6 +45,7 @@
oris rn,rn,[EMAIL PROTECTED]; \
ori rn,rn,[EMAIL PROTECTED]
+#define KDUMP_SIGNATURE 0xfeed1234
.machine ppc64
.globl purgatory_start
@@ -64,6 +65,7 @@ master:
isync
mr 17,3 # save cpu id to r17
mr 15,4 # save physical address in reg15
+ mr 18,6 # save kdump flag in reg18
LOADADDR(6,my_toc)
ld 2,0(6) #setup toc
@@ -94,6 +96,12 @@ master:
mtctr 4 # prepare branch too
mr 3,16 # restore dt address
+ LOADADDR(6,KDUMP_SIGNATURE)
+ cmpd 18,6
+ bne regular
+ li 7,1
+ std 7,24(4) # mark kdump flag at kernel
+regular:
lwz 7,0(4) # get the first instruction that we stole
stw 7,0(0) # and put it in the slave loop at 0
# skip cache flush, do we care?
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