[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, 33 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 2f73f705d56..b5199752ac6 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -356,9 +356,42 @@ void __init init_IRQ(void)
 {
 	if (ppc_md.init_IRQ)
 		ppc_md.init_IRQ();
+
+	exc_lvl_ctx_init();
+
 	irq_ctx_init();
 }
 
+#if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
+struct thread_info   *critirq_ctx[NR_CPUS] __read_mostly;
+struct thread_info    *dbgirq_ctx[NR_CPUS] __read_mostly;
+struct thread_info *mcheckirq_ctx[NR_CPUS] __read_mostly;
+
+void exc_lvl_ctx_init(void)
+{
+	struct thread_info *tp;
+	int i;
+
+	for_each_possible_cpu(i) {
+		memset((void *)critirq_ctx[i], 0, THREAD_SIZE);
+		tp = critirq_ctx[i];
+		tp->cpu = i;
+		tp->preempt_count = 0;
+
+#ifdef CONFIG_BOOKE
+		memset((void *)dbgirq_ctx[i], 0, THREAD_SIZE);
+		tp = dbgirq_ctx[i];
+		tp->cpu = i;
+		tp->preempt_count = 0;
+
+		memset((void *)mcheckirq_ctx[i], 0, THREAD_SIZE);
+		tp = mcheckirq_ctx[i];
+		tp->cpu = i;
+		tp->preempt_count = HARDIRQ_OFFSET;
+#endif
+	}
+}
+#endif
 
 #ifdef CONFIG_IRQSTACKS
 struct thread_info *softirq_ctx[NR_CPUS] __read_mostly;