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>

diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c
index b842fc82be15a079f5a9268fcddcc222cf41ccfc..1d3d0e71b0440847e16d4c381eaef5dbe68bb082 100644 (file)
--- 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))