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authorThomas Gleixner <tglx@linutronix.de>2008-05-05 15:58:15 +0200
committerIngo Molnar <mingo@elte.hu>2008-05-12 21:28:06 +0200
commitde9b10af1287bf25b9c0433de53a2e95ef611aa7 (patch)
tree9bc83f349f9ca651ce9d7c56aee9c3c3c7ae79e0 /arch
parent04b361abfdc522239e3a071f3afdebf5787d9f03 (diff)
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>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/irq_32.c136
1 files changed, 75 insertions, 61 deletions
diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index 3f76561da81..1c470d2e5af 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -48,6 +48,29 @@ void ack_bad_irq(unsigned int irq)
#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 @@ union irq_ctx {
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"
@@ -81,22 +98,61 @@ static inline void call_on_stack2(void *func, void *stack,
: "memory", "cc", "ecx");
}
+static inline int
+execute_on_irq_stack(int overflow, struct irq_desc *desc, int irq)
+{
+ union irq_ctx *curctx, *irqctx;
+ u32 *isp;
+
+ curctx = (union irq_ctx *) current_thread_info();
+ irqctx = hardirq_ctx[smp_processor_id()];
+
+ /*
+ * this is where we switch to the IRQ stack. However, if we are
+ * already using the IRQ stack (because we interrupted a hardirq
+ * handler) we can't do that and just have to keep using the
+ * current stack (which is the irq stack already after all)
+ */
+ if (unlikely(curctx == irqctx))
+ return 0;
+
+ /* 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;
+
+ /*
+ * 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);
+
+ 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
+
/*
* 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;
+ int overflow, irq = ~regs->orig_ax;
struct irq_desc *desc = irq_desc + irq;
-#ifdef CONFIG_4KSTACKS
- 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",
@@ -106,54 +162,12 @@ unsigned int do_IRQ(struct pt_regs *regs)
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()];
+ overflow = check_stack_overflow();
- /*
- * this is where we switch to the IRQ stack. However, if we are
- * already using the IRQ stack (because we interrupted a hardirq
- * 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;
-
- /*
- * 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);
-
- /* Execute warning on interrupt stack */
+ if (!execute_on_irq_stack(overflow, desc, irq)) {
if (unlikely(overflow))
- call_on_stack2(stack_overflow, isp, 0, 0);
-
- call_on_stack2(desc->handle_irq, isp, irq, (unsigned long)desc);
- } else
-#endif
- {
- /* AK: Slightly bogus here */
- if (overflow)
- stack_overflow();
+ print_stack_overflow();
desc->handle_irq(irq, desc);
}