x86: clean up stack overflow debug check

Impact: cleanup

Simplify the irq-sampled stack overflow debug check:

 - eliminate an #idef

 - use WARN_ONCE() to emit a single warning (all bets are off
   after the first such warning anyway)

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 10 insertions, 15 deletions

diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c
index b842fc82be15..1d3d0e71b044 100644
--- a/arch/x86/kernel/irq_64.c
+++ b/arch/x86/kernel/irq_64.c
@@ -18,7 +18,6 @@
 #include <asm/idle.h>
 #include <asm/smp.h>
 
-#ifdef CONFIG_DEBUG_STACKOVERFLOW
 /*
  * Probabilistic stack overflow check:
  *
@@ -28,20 +27,18 @@
  */
 static inline void stack_overflow_check(struct pt_regs *regs)
 {
+#ifdef CONFIG_DEBUG_STACKOVERFLOW
         u64 curbase = (u64)task_stack_page(current);
-        static unsigned long warned = INITIAL_JIFFIES - 60*HZ;
-
-        if (regs->sp >= curbase && regs->sp <= curbase + THREAD_SIZE &&
-                        regs->sp < curbase + sizeof(struct thread_info) +
-                        sizeof(struct pt_regs) + 128 &&
-                        time_after(jiffies, warned + 60*HZ)) {
-                printk("do_IRQ: %s near stack overflow (cur:%Lx,sp:%lx)\n",
-                       current->comm, curbase, regs->sp);
-                show_stack(NULL,NULL);
-                warned = jiffies;
-        }
-}
+
+        WARN_ONCE(regs->sp >= curbase &&
+                  regs->sp <= curbase + THREAD_SIZE &&
+                  regs->sp <  curbase + sizeof(struct thread_info) +
+                                        sizeof(struct pt_regs) + 128,
+
+                  "do_IRQ: %s near stack overflow (cur:%Lx,sp:%lx)\n",
+                        current->comm, curbase, regs->sp);
 #endif
+}
 
 /*
  * do_IRQ handles all normal device IRQ's (the special
@@ -61,9 +58,7 @@ asmlinkage unsigned int do_IRQ(struct pt_regs *regs)
         irq_enter();
         irq = __get_cpu_var(vector_irq)[vector];
 
-#ifdef CONFIG_DEBUG_STACKOVERFLOW
         stack_overflow_check(regs);
-#endif
 
         desc = irq_to_desc(irq);
         if (likely(desc))