sh: Replace DEBUG_STACKOVERFLOW with STACK_DEBUG.

STACK_DEBUG ties in to mcount in order to do function-granular stack
overflow checks as opposed to lazily checking from IRQ context. As the
default is nohz, the frequency of overflow checking is too irregular to
catch much useful information, and so the mcount approach employed by
sparc64 is adopted instead.

This kills off the old check entirely from the do_IRQ() path and now
adopts CONFIG_MCOUNT instead.

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

1 files changed, 0 insertions, 17 deletions

diff --git a/arch/sh/kernel/irq.c b/arch/sh/kernel/irq.c
index 3d09062f4682..278c68c60488 100644
--- a/arch/sh/kernel/irq.c
+++ b/arch/sh/kernel/irq.c
@@ -114,23 +114,6 @@ asmlinkage int do_IRQ(unsigned int irq, struct pt_regs *regs)
 #endif
 
         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
-
         irq = irq_demux(intc_evt2irq(irq));
 
 #ifdef CONFIG_IRQSTACKS