1 files changed, 100 insertions, 92 deletions

diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index 6a340485249..1abcb50b48a 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -104,32 +104,42 @@ in_irq_stack(unsigned long *stack, unsigned long *irq_stack,
 	return (stack >= irq_stack && stack < irq_stack_end);
 }
 
-/*
- * We are returning from the irq stack and go to the previous one.
- * If the previous stack is also in the irq stack, then bp in the first
- * frame of the irq stack points to the previous, interrupted one.
- * Otherwise we have another level of indirection: We first save
- * the bp of the previous stack, then we switch the stack to the irq one
- * and save a new bp that links to the previous one.
- * (See save_args())
- */
-static inline unsigned long
-fixup_bp_irq_link(unsigned long bp, unsigned long *stack,
-		  unsigned long *irq_stack, unsigned long *irq_stack_end)
+static const unsigned long irq_stack_size =
+	(IRQ_STACK_SIZE - 64) / sizeof(unsigned long);
+
+enum stack_type {
+	STACK_IS_UNKNOWN,
+	STACK_IS_NORMAL,
+	STACK_IS_EXCEPTION,
+	STACK_IS_IRQ,
+};
+
+static enum stack_type
+analyze_stack(int cpu, struct task_struct *task, unsigned long *stack,
+	      unsigned long **stack_end, unsigned long *irq_stack,
+	      unsigned *used, char **id)
 {
-#ifdef CONFIG_FRAME_POINTER
-	struct stack_frame *frame = (struct stack_frame *)bp;
-	unsigned long next;
+	unsigned long addr;
 
-	if (!in_irq_stack(stack, irq_stack, irq_stack_end)) {
-		if (!probe_kernel_address(&frame->next_frame, next))
-			return next;
-		else
-			WARN_ONCE(1, "Perf: bad frame pointer = %p in "
-				  "callchain\n", &frame->next_frame);
-	}
-#endif
-	return bp;
+	addr = ((unsigned long)stack & (~(THREAD_SIZE - 1)));
+	if ((unsigned long)task_stack_page(task) == addr)
+		return STACK_IS_NORMAL;
+
+	*stack_end = in_exception_stack(cpu, (unsigned long)stack,
+					used, id);
+	if (*stack_end)
+		return STACK_IS_EXCEPTION;
+
+	if (!irq_stack)
+		return STACK_IS_NORMAL;
+
+	*stack_end = irq_stack;
+	irq_stack = irq_stack - irq_stack_size;
+
+	if (in_irq_stack(stack, irq_stack, *stack_end))
+		return STACK_IS_IRQ;
+
+	return STACK_IS_UNKNOWN;
 }
 
 /*
@@ -144,85 +154,88 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
 		const struct stacktrace_ops *ops, void *data)
 {
 	const unsigned cpu = get_cpu();
-	unsigned long *irq_stack_end =
-		(unsigned long *)per_cpu(irq_stack_ptr, cpu);
-	unsigned used = 0;
 	struct thread_info *tinfo;
+	unsigned long *irq_stack = (unsigned long *)per_cpu(irq_stack_ptr, cpu);
+	unsigned long dummy;
+	unsigned used = 0;
 	int graph = 0;
+	int done = 0;
 
 	if (!task)
 		task = current;
 
 	if (!stack) {
-		unsigned long dummy;
-		stack = &dummy;
-		if (task && task != current)
+		if (regs)
+			stack = (unsigned long *)regs->sp;
+		else if (task != current)
 			stack = (unsigned long *)task->thread.sp;
+		else
+			stack = &dummy;
 	}
 
-#ifdef CONFIG_FRAME_POINTER
-	if (!bp) {
-		if (task == current) {
-			/* Grab bp right from our regs */
-			get_bp(bp);
-		} else {
-			/* bp is the last reg pushed by switch_to */
-			bp = *(unsigned long *) task->thread.sp;
-		}
-	}
-#endif
-
+	if (!bp)
+		bp = stack_frame(task, regs);
 	/*
 	 * Print function call entries in all stacks, starting at the
 	 * current stack address. If the stacks consist of nested
 	 * exceptions
 	 */
 	tinfo = task_thread_info(task);
-	for (;;) {
+	while (!done) {
+		unsigned long *stack_end;
+		enum stack_type stype;
 		char *id;
-		unsigned long *estack_end;
-		estack_end = in_exception_stack(cpu, (unsigned long)stack,
-						&used, &id);
 
-		if (estack_end) {
+		stype = analyze_stack(cpu, task, stack, &stack_end,
+				      irq_stack, &used, &id);
+
+		/* Default finish unless specified to continue */
+		done = 1;
+
+		switch (stype) {
+
+		/* Break out early if we are on the thread stack */
+		case STACK_IS_NORMAL:
+			break;
+
+		case STACK_IS_EXCEPTION:
+
 			if (ops->stack(data, id) < 0)
 				break;
 
 			bp = ops->walk_stack(tinfo, stack, bp, ops,
-					     data, estack_end, &graph);
+					     data, stack_end, &graph);
 			ops->stack(data, "<EOE>");
 			/*
 			 * We link to the next stack via the
 			 * second-to-last pointer (index -2 to end) in the
 			 * exception stack:
 			 */
-			stack = (unsigned long *) estack_end[-2];
-			continue;
-		}
-		if (irq_stack_end) {
-			unsigned long *irq_stack;
-			irq_stack = irq_stack_end -
-				(IRQ_STACK_SIZE - 64) / sizeof(*irq_stack);
-
-			if (in_irq_stack(stack, irq_stack, irq_stack_end)) {
-				if (ops->stack(data, "IRQ") < 0)
-					break;
-				bp = ops->walk_stack(tinfo, stack, bp,
-					ops, data, irq_stack_end, &graph);
-				/*
-				 * We link to the next stack (which would be
-				 * the process stack normally) the last
-				 * pointer (index -1 to end) in the IRQ stack:
-				 */
-				stack = (unsigned long *) (irq_stack_end[-1]);
-				bp = fixup_bp_irq_link(bp, stack, irq_stack,
-						       irq_stack_end);
-				irq_stack_end = NULL;
-				ops->stack(data, "EOI");
-				continue;
-			}
+			stack = (unsigned long *) stack_end[-2];
+			done = 0;
+			break;
+
+		case STACK_IS_IRQ:
+
+			if (ops->stack(data, "IRQ") < 0)
+				break;
+			bp = ops->walk_stack(tinfo, stack, bp,
+				     ops, data, stack_end, &graph);
+			/*
+			 * We link to the next stack (which would be
+			 * the process stack normally) the last
+			 * pointer (index -1 to end) in the IRQ stack:
+			 */
+			stack = (unsigned long *) (stack_end[-1]);
+			irq_stack = NULL;
+			ops->stack(data, "EOI");
+			done = 0;
+			break;
+
+		case STACK_IS_UNKNOWN:
+			ops->stack(data, "UNK");
+			break;
 		}
-		break;
 	}
 
 	/*
@@ -265,36 +278,31 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
 		if (stack >= irq_stack && stack <= irq_stack_end) {
 			if (stack == irq_stack_end) {
 				stack = (unsigned long *) (irq_stack_end[-1]);
-				printk(KERN_CONT " <EOI> ");
+				pr_cont(" <EOI> ");
 			}
 		} else {
 		if (((long) stack & (THREAD_SIZE-1)) == 0)
 			break;
 		}
 		if (i && ((i % STACKSLOTS_PER_LINE) == 0))
-			printk(KERN_CONT "\n");
-		printk(KERN_CONT " %016lx", *stack++);
+			pr_cont("\n");
+		pr_cont(" %016lx", *stack++);
 		touch_nmi_watchdog();
 	}
 	preempt_enable();
 
-	printk(KERN_CONT "\n");
+	pr_cont("\n");
 	show_trace_log_lvl(task, regs, sp, bp, log_lvl);
 }
 
-void show_registers(struct pt_regs *regs)
+void show_regs(struct pt_regs *regs)
 {
 	int i;
 	unsigned long sp;
-	const int cpu = smp_processor_id();
-	struct task_struct *cur = current;
 
 	sp = regs->sp;
-	printk("CPU %d ", cpu);
-	print_modules();
+	show_regs_print_info(KERN_DEFAULT);
 	__show_regs(regs, 1);
-	printk("Process %s (pid: %d, threadinfo %p, task %p)\n",
-		cur->comm, cur->pid, task_thread_info(cur), cur);
 
 	/*
 	 * When in-kernel, we also print out the stack and code at the
@@ -306,11 +314,11 @@ void show_registers(struct pt_regs *regs)
 		unsigned char c;
 		u8 *ip;
 
-		printk(KERN_EMERG "Stack:\n");
+		printk(KERN_DEFAULT "Stack:\n");
 		show_stack_log_lvl(NULL, regs, (unsigned long *)sp,
-				regs->bp, KERN_EMERG);
+				   0, KERN_DEFAULT);
 
-		printk(KERN_EMERG "Code: ");
+		printk(KERN_DEFAULT "Code: ");
 
 		ip = (u8 *)regs->ip - code_prologue;
 		if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
@@ -321,16 +329,16 @@ void show_registers(struct pt_regs *regs)
 		for (i = 0; i < code_len; i++, ip++) {
 			if (ip < (u8 *)PAGE_OFFSET ||
 					probe_kernel_address(ip, c)) {
-				printk(" Bad RIP value.");
+				pr_cont(" Bad RIP value.");
 				break;
 			}
 			if (ip == (u8 *)regs->ip)
-				printk("<%02x> ", c);
+				pr_cont("<%02x> ", c);
 			else
-				printk("%02x ", c);
+				pr_cont("%02x ", c);
 		}
 	}
-	printk("\n");
+	pr_cont("\n");
 }
 
 int is_valid_bugaddr(unsigned long ip)