powerpc/kexec: Switch to a static PACA on the way out

With dynamic PACAs, the kexecing CPU's PACA won't lie within the kernel
static data and there is a chance that something may stomp it when preparing
to kexec.  This patch switches this final CPU to a static PACA just before
we pull the switch.

Signed-off-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c
index f88acf0218db..3db8d64f40e1 100644
--- a/arch/powerpc/kernel/paca.c
+++ b/arch/powerpc/kernel/paca.c
@@ -105,6 +105,16 @@ void __init initialise_paca(struct paca_struct *new_paca, int cpu)
 #endif /* CONFIG_PPC_STD_MMU_64 */
 }
 
+/* Put the paca pointer into r13 and SPRG_PACA */
+void setup_paca(struct paca_struct *new_paca)
+{
+        local_paca = new_paca;
+        mtspr(SPRN_SPRG_PACA, local_paca);
+#ifdef CONFIG_PPC_BOOK3E
+        mtspr(SPRN_SPRG_TLB_EXFRAME, local_paca->extlb);
+#endif
+}
+
 static int __initdata paca_size;
 
 void __init allocate_pacas(void)