3 files changed, 35 insertions, 0 deletions

diff --git a/arch/mips/Kconfig.debug b/arch/mips/Kconfig.debug
index 43dc27997730..f437cd1fafb8 100644
--- a/arch/mips/Kconfig.debug
+++ b/arch/mips/Kconfig.debug
@@ -67,6 +67,15 @@ config CMDLINE_OVERRIDE
 
           Normally, you will choose 'N' here.
 
+config DEBUG_STACKOVERFLOW
+        bool "Check for stack overflows"
+        depends on DEBUG_KERNEL
+        help
+          This option will cause messages to be printed if free stack space
+          drops below a certain limit(2GB on MIPS). The debugging option
+          provides another way to check stack overflow happened on kernel mode
+          stack usually caused by nested interruption.
+
 config DEBUG_STACK_USAGE
         bool "Enable stack utilization instrumentation"
         depends on DEBUG_KERNEL
diff --git a/arch/mips/include/asm/thread_info.h b/arch/mips/include/asm/thread_info.h
index 70df9c0d3c5b..d309556cacf8 100644
--- a/arch/mips/include/asm/thread_info.h
+++ b/arch/mips/include/asm/thread_info.h
@@ -83,6 +83,8 @@ register struct thread_info *__current_thread_info __asm__("$28");
 #define THREAD_SIZE (PAGE_SIZE << THREAD_SIZE_ORDER)
 #define THREAD_MASK (THREAD_SIZE - 1UL)
 
+#define STACK_WARN      (THREAD_SIZE / 8)
+
 #define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
 
 #ifdef CONFIG_DEBUG_STACK_USAGE
diff --git a/arch/mips/kernel/irq.c b/arch/mips/kernel/irq.c
index c6345f579a8a..4f93db58a79e 100644
--- a/arch/mips/kernel/irq.c
+++ b/arch/mips/kernel/irq.c
@@ -151,6 +151,29 @@ void __init init_IRQ(void)
 #endif
 }
 
+#ifdef DEBUG_STACKOVERFLOW
+static inline void check_stack_overflow(void)
+{
+        unsigned long sp;
+
+        __asm__ __volatile__("move %0, $sp" : "=r" (sp));
+        sp &= THREAD_MASK;
+
+        /*
+         * Check for stack overflow: is there less than STACK_WARN free?
+         * STACK_WARN is defined as 1/8 of THREAD_SIZE by default.
+         */
+        if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
+                printk("do_IRQ: stack overflow: %ld\n",
+                       sp - sizeof(struct thread_info));
+                dump_stack();
+        }
+}
+#else
+static inline void check_stack_overflow(void) {}
+#endif
+
+
 /*
  * do_IRQ handles all normal device IRQ's (the special
  * SMP cross-CPU interrupts have their own specific
@@ -159,6 +182,7 @@ void __init init_IRQ(void)
 void __irq_entry do_IRQ(unsigned int irq)
 {
         irq_enter();
+        check_stack_overflow();
         __DO_IRQ_SMTC_HOOK(irq);
         generic_handle_irq(irq);
         irq_exit();