x86: janitor stack overflow warning patch
Add KERN_WARNING to the printk as this could not be done in the
original patch, which allegedly only moves code around.
Un#ifdef do_IRQ.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index 3f76561..1c470d2 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -48,6 +48,29 @@
#endif
}
+#ifdef CONFIG_DEBUG_STACKOVERFLOW
+/* Debugging check for stack overflow: is there less than 1KB free? */
+static int check_stack_overflow(void)
+{
+ long sp;
+
+ __asm__ __volatile__("andl %%esp,%0" :
+ "=r" (sp) : "0" (THREAD_SIZE - 1));
+
+ return sp < (sizeof(struct thread_info) + STACK_WARN);
+}
+
+static void print_stack_overflow(void)
+{
+ printk(KERN_WARNING "low stack detected by irq handler\n");
+ dump_stack();
+}
+
+#else
+static inline int check_stack_overflow(void) { return 0; }
+static inline void print_stack_overflow(void) { }
+#endif
+
#ifdef CONFIG_4KSTACKS
/*
* per-CPU IRQ handling contexts (thread information and stack)
@@ -59,18 +82,12 @@
static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly;
static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
-#endif
-static void stack_overflow(void)
-{
- printk("low stack detected by irq handler\n");
- dump_stack();
-}
-
-static inline void call_on_stack2(void *func, void *stack,
- unsigned long arg1, unsigned long arg2)
+static inline void call_on_stack(void *func, void *stack,
+ unsigned long arg1, void *arg2)
{
unsigned long bx;
+
asm volatile(
" xchgl %%ebx,%%esp \n"
" call *%%edi \n"
@@ -81,44 +98,11 @@
: "memory", "cc", "ecx");
}
-/*
- * do_IRQ handles all normal device IRQ's (the special
- * SMP cross-CPU interrupts have their own specific
- * handlers).
- */
-unsigned int do_IRQ(struct pt_regs *regs)
-{
- struct pt_regs *old_regs;
- /* high bit used in ret_from_ code */
- int irq = ~regs->orig_ax;
- struct irq_desc *desc = irq_desc + irq;
-#ifdef CONFIG_4KSTACKS
+static inline int
+execute_on_irq_stack(int overflow, struct irq_desc *desc, int irq)
+{
union irq_ctx *curctx, *irqctx;
u32 *isp;
-#endif
- int overflow = 0;
-
- if (unlikely((unsigned)irq >= NR_IRQS)) {
- printk(KERN_EMERG "%s: cannot handle IRQ %d\n",
- __func__, irq);
- BUG();
- }
-
- old_regs = set_irq_regs(regs);
- irq_enter();
-#ifdef CONFIG_DEBUG_STACKOVERFLOW
- /* Debugging check for stack overflow: is there less than 1KB free? */
- {
- long sp;
-
- __asm__ __volatile__("andl %%esp,%0" :
- "=r" (sp) : "0" (THREAD_SIZE - 1));
- if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN)))
- overflow = 1;
- }
-#endif
-
-#ifdef CONFIG_4KSTACKS
curctx = (union irq_ctx *) current_thread_info();
irqctx = hardirq_ctx[smp_processor_id()];
@@ -129,31 +113,61 @@
* handler) we can't do that and just have to keep using the
* current stack (which is the irq stack already after all)
*/
- if (curctx != irqctx) {
- /* build the stack frame on the IRQ stack */
- isp = (u32*) ((char*)irqctx + sizeof(*irqctx));
- irqctx->tinfo.task = curctx->tinfo.task;
- irqctx->tinfo.previous_esp = current_stack_pointer;
+ if (unlikely(curctx == irqctx))
+ return 0;
- /*
- * Copy the softirq bits in preempt_count so that the
- * softirq checks work in the hardirq context.
- */
- irqctx->tinfo.preempt_count =
- (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) |
- (curctx->tinfo.preempt_count & SOFTIRQ_MASK);
+ /* build the stack frame on the IRQ stack */
+ isp = (u32 *) ((char*)irqctx + sizeof(*irqctx));
+ irqctx->tinfo.task = curctx->tinfo.task;
+ irqctx->tinfo.previous_esp = current_stack_pointer;
- /* Execute warning on interrupt stack */
- if (unlikely(overflow))
- call_on_stack2(stack_overflow, isp, 0, 0);
+ /*
+ * Copy the softirq bits in preempt_count so that the
+ * softirq checks work in the hardirq context.
+ */
+ irqctx->tinfo.preempt_count =
+ (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) |
+ (curctx->tinfo.preempt_count & SOFTIRQ_MASK);
- call_on_stack2(desc->handle_irq, isp, irq, (unsigned long)desc);
- } else
+ if (unlikely(overflow))
+ call_on_stack(print_stack_overflow, isp, 0, NULL);
+
+ call_on_stack(desc->handle_irq, isp, irq, desc);
+
+ return 1;
+}
+
+#else
+static inline int
+execute_on_irq_stack(int overflow, struct irq_desc *desc, int irq) { return 0; }
#endif
- {
- /* AK: Slightly bogus here */
- if (overflow)
- stack_overflow();
+
+/*
+ * do_IRQ handles all normal device IRQ's (the special
+ * SMP cross-CPU interrupts have their own specific
+ * handlers).
+ */
+unsigned int do_IRQ(struct pt_regs *regs)
+{
+ struct pt_regs *old_regs;
+ /* high bit used in ret_from_ code */
+ int overflow, irq = ~regs->orig_ax;
+ struct irq_desc *desc = irq_desc + irq;
+
+ if (unlikely((unsigned)irq >= NR_IRQS)) {
+ printk(KERN_EMERG "%s: cannot handle IRQ %d\n",
+ __func__, irq);
+ BUG();
+ }
+
+ old_regs = set_irq_regs(regs);
+ irq_enter();
+
+ overflow = check_stack_overflow();
+
+ if (!execute_on_irq_stack(overflow, desc, irq)) {
+ if (unlikely(overflow))
+ print_stack_overflow();
desc->handle_irq(irq, desc);
}