[POWERPC] Move to runtime allocated exception stacks

For the additonal exception levels (critical, debug, machine check) on
40x/book-e we were using "static" allocations of the stack in the
associated head.S.

Move to a runtime allocation to make the code a bit easier to read as
we mimic how we handle IRQ stacks.  Its also a bit easier to setup the
stack with a "dummy" thread_info in C code.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Acked-by: Paul Mackerras <paulus@samba.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/include/asm-powerpc/irq.h b/include/asm-powerpc/irq.h
index 5089deb8fec3..1ef8e304e0ea 100644
--- a/include/asm-powerpc/irq.h
+++ b/include/asm-powerpc/irq.h
@@ -619,6 +619,19 @@ struct pt_regs;
 
 #define __ARCH_HAS_DO_SOFTIRQ
 
+#if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
+/*
+ * Per-cpu stacks for handling critical, debug and machine check
+ * level interrupts.
+ */
+extern struct thread_info *critirq_ctx[NR_CPUS];
+extern struct thread_info *dbgirq_ctx[NR_CPUS];
+extern struct thread_info *mcheckirq_ctx[NR_CPUS];
+extern void exc_lvl_ctx_init(void);
+#else
+#define exc_lvl_ctx_init()
+#endif
+
 #ifdef CONFIG_IRQSTACKS
 /*
  * Per-cpu stacks for handling hard and soft interrupts.