powerpc/kexec: Adds correct calling convention for kexec purgatory

Call kexec purgatory code correctly. We were getting lucky before.
If you examine the powerpc 32bit kexec "purgatory" code you will
see it expects the following:

>From kexec-tools: purgatory/arch/ppc/v2wrap_32.S
-> calling convention:
->   r3 = physical number of this cpu (all cpus)
->   r4 = address of this chunk (master only)

As such, we need to set r3 to the current core, r4 happens to be
unused by purgatory at the moment but we go ahead and set it
here as well

Signed-off-by: Matthew McClintock <msm@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S
index 6bbd7a604d24..a7a570dcdd57 100644
--- a/arch/powerpc/kernel/misc_32.S
+++ b/arch/powerpc/kernel/misc_32.S
@@ -810,6 +810,9 @@ relocate_new_kernel:
         isync
         sync
 
+        mfspr   r3, SPRN_PIR /* current core we are running on */
+        mr      r4, r5 /* load physical address of chunk called */
+
         /* jump to the entry point, usually the setup routine */
         mtlr    r5
         blrl