sh: stack debugging support.

This adds a DEBUG_STACK_USAGE and DEBUG_STACKOVERFLOW for SH.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 16 insertions, 1 deletions

diff --git a/arch/sh/kernel/irq.c b/arch/sh/kernel/irq.c
index c2e07f7f3496..7066611aeb72 100644
--- a/arch/sh/kernel/irq.c
+++ b/arch/sh/kernel/irq.c
@@ -60,7 +60,6 @@ unlock:
 }
 #endif
 
-
 asmlinkage int do_IRQ(unsigned long r4, unsigned long r5,
                       unsigned long r6, unsigned long r7,
                       struct pt_regs regs)
@@ -69,6 +68,22 @@ asmlinkage int do_IRQ(unsigned long r4, unsigned long r5,
 
         irq_enter();
 
+#ifdef CONFIG_DEBUG_STACKOVERFLOW
+        /* Debugging check for stack overflow: is there less than 1KB free? */
+        {
+                long sp;
+
+                __asm__ __volatile__ ("and r15, %0" :
+                                        "=r" (sp) : "0" (THREAD_SIZE - 1));
+
+                if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
+                        printk("do_IRQ: stack overflow: %ld\n",
+                               sp - sizeof(struct thread_info));
+                        dump_stack();
+                }
+        }
+#endif
+
 #ifdef CONFIG_CPU_HAS_INTEVT
         __asm__ __volatile__ (
 #ifdef CONFIG_CPU_HAS_SR_RB