[PATCH] powerpc: Don't overwrite flat device tree with kdump kernel

It's possible for prom_init to allocate the flat device tree inside the
kdump crash kernel region. If this happens, when we load the kdump kernel we
overwrite the flattened device tree, which is bad.

We could make prom_init try and avoid allocating inside the crash kernel
region, but then we run into issues if the crash kernel region uses all the
space inside the RMO. The easiest solution is to move the flat device tree
once we're running in the kernel.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/asm-powerpc/prom.h b/include/asm-powerpc/prom.h
index 5b2bd4eefb01..cbd297f44cce 100644
--- a/include/asm-powerpc/prom.h
+++ b/include/asm-powerpc/prom.h
@@ -222,5 +222,7 @@ extern int of_address_to_resource(struct device_node *dev, int index,
 extern int of_pci_address_to_resource(struct device_node *dev, int bar,
                                       struct resource *r);
 
+extern void kdump_move_device_tree(void);
+
 #endif /* __KERNEL__ */
 #endif /* _POWERPC_PROM_H */