1 files changed, 27 insertions, 193 deletions

diff --git a/arch/x86_64/kernel/stacktrace.c b/arch/x86_64/kernel/stacktrace.c
index 32cf55e..6026b31 100644
--- a/arch/x86_64/kernel/stacktrace.c
+++ b/arch/x86_64/kernel/stacktrace.c
@@ -7,215 +7,49 @@
  */
 #include <linux/sched.h>
 #include <linux/stacktrace.h>
+#include <linux/module.h>
+#include <asm/stacktrace.h>
 
-#include <asm/smp.h>
-
-static inline int
-in_range(unsigned long start, unsigned long addr, unsigned long end)
+static void save_stack_warning(void *data, char *msg)
 {
-	return addr >= start && addr <= end;
 }
 
-static unsigned long
-get_stack_end(struct task_struct *task, unsigned long stack)
+static void
+save_stack_warning_symbol(void *data, char *msg, unsigned long symbol)
 {
-	unsigned long stack_start, stack_end, flags;
-	int i, cpu;
-
-	/*
-	 * The most common case is that we are in the task stack:
-	 */
-	stack_start = (unsigned long)task->thread_info;
-	stack_end = stack_start + THREAD_SIZE;
-
-	if (in_range(stack_start, stack, stack_end))
-		return stack_end;
-
-	/*
-	 * We are in an interrupt if irqstackptr is set:
-	 */
-	raw_local_irq_save(flags);
-	cpu = safe_smp_processor_id();
-	stack_end = (unsigned long)cpu_pda(cpu)->irqstackptr;
-
-	if (stack_end) {
-		stack_start = stack_end & ~(IRQSTACKSIZE-1);
-		if (in_range(stack_start, stack, stack_end))
-			goto out_restore;
-		/*
-		 * We get here if we are in an IRQ context but we
-		 * are also in an exception stack.
-		 */
-	}
-
-	/*
-	 * Iterate over all exception stacks, and figure out whether
-	 * 'stack' is in one of them:
-	 */
-	for (i = 0; i < N_EXCEPTION_STACKS; i++) {
-		/*
-		 * set 'end' to the end of the exception stack.
-		 */
-		stack_end = per_cpu(init_tss, cpu).ist[i];
-		stack_start = stack_end - EXCEPTION_STKSZ;
-
-		/*
-		 * Is 'stack' above this exception frame's end?
-		 * If yes then skip to the next frame.
-		 */
-		if (stack >= stack_end)
-			continue;
-		/*
-		 * Is 'stack' above this exception frame's start address?
-		 * If yes then we found the right frame.
-		 */
-		if (stack >= stack_start)
-			goto out_restore;
-
-		/*
-		 * If this is a debug stack, and if it has a larger size than
-		 * the usual exception stacks, then 'stack' might still
-		 * be within the lower portion of the debug stack:
-		 */
-#if DEBUG_STKSZ > EXCEPTION_STKSZ
-		if (i == DEBUG_STACK - 1 && stack >= stack_end - DEBUG_STKSZ) {
-			/*
-			 * Black magic. A large debug stack is composed of
-			 * multiple exception stack entries, which we
-			 * iterate through now. Dont look:
-			 */
-			do {
-				stack_end -= EXCEPTION_STKSZ;
-				stack_start -= EXCEPTION_STKSZ;
-			} while (stack < stack_start);
-
-			goto out_restore;
-		}
-#endif
-	}
-	/*
-	 * Ok, 'stack' is not pointing to any of the system stacks.
-	 */
-	stack_end = 0;
-
-out_restore:
-	raw_local_irq_restore(flags);
-
-	return stack_end;
 }
 
-
-/*
- * Save stack-backtrace addresses into a stack_trace buffer:
- */
-static inline unsigned long
-save_context_stack(struct stack_trace *trace, unsigned int skip,
-		   unsigned long stack, unsigned long stack_end)
+static int save_stack_stack(void *data, char *name)
 {
-	unsigned long addr;
-
-#ifdef CONFIG_FRAME_POINTER
-	unsigned long prev_stack = 0;
+	struct stack_trace *trace = (struct stack_trace *)data;
+	return trace->all_contexts ? 0 : -1;
+}
 
-	while (in_range(prev_stack, stack, stack_end)) {
-		pr_debug("stack:          %p\n", (void *)stack);
-		addr = (unsigned long)(((unsigned long *)stack)[1]);
-		pr_debug("addr:           %p\n", (void *)addr);
-		if (!skip)
-			trace->entries[trace->nr_entries++] = addr-1;
-		else
-			skip--;
-		if (trace->nr_entries >= trace->max_entries)
-			break;
-		if (!addr)
-			return 0;
-		/*
-		 * Stack frames must go forwards (otherwise a loop could
-		 * happen if the stackframe is corrupted), so we move
-		 * prev_stack forwards:
-		 */
-		prev_stack = stack;
-		stack = (unsigned long)(((unsigned long *)stack)[0]);
-	}
-	pr_debug("invalid:        %p\n", (void *)stack);
-#else
-	while (stack < stack_end) {
-		addr = ((unsigned long *)stack)[0];
-		stack += sizeof(long);
-		if (__kernel_text_address(addr)) {
-			if (!skip)
-				trace->entries[trace->nr_entries++] = addr-1;
-			else
-				skip--;
-			if (trace->nr_entries >= trace->max_entries)
-				break;
-		}
+static void save_stack_address(void *data, unsigned long addr)
+{
+	struct stack_trace *trace = (struct stack_trace *)data;
+	if (trace->skip > 0) {
+		trace->skip--;
+		return;
 	}
-#endif
-	return stack;
+	if (trace->nr_entries < trace->max_entries - 1)
+		trace->entries[trace->nr_entries++] = addr;
 }
 
-#define MAX_STACKS 10
+static struct stacktrace_ops save_stack_ops = {
+	.warning = save_stack_warning,
+	.warning_symbol = save_stack_warning_symbol,
+	.stack = save_stack_stack,
+	.address = save_stack_address,
+};
 
 /*
  * Save stack-backtrace addresses into a stack_trace buffer.
- * If all_contexts is set, all contexts (hardirq, softirq and process)
- * are saved. If not set then only the current context is saved.
  */
-void save_stack_trace(struct stack_trace *trace,
-		      struct task_struct *task, int all_contexts,
-		      unsigned int skip)
+void save_stack_trace(struct stack_trace *trace, struct task_struct *task)
 {
-	unsigned long stack = (unsigned long)&stack;
-	int i, nr_stacks = 0, stacks_done[MAX_STACKS];
-
-	WARN_ON(trace->nr_entries || !trace->max_entries);
-
-	if (!task)
-		task = current;
-
-	pr_debug("task: %p, ti: %p\n", task, task->thread_info);
-
-	if (!task || task == current) {
-		/* Grab rbp right from our regs: */
-		asm ("mov %%rbp, %0" : "=r" (stack));
-		pr_debug("rbp:            %p\n", (void *)stack);
-	} else {
-		/* rbp is the last reg pushed by switch_to(): */
-		stack = task->thread.rsp;
-		pr_debug("other task rsp: %p\n", (void *)stack);
-		stack = (unsigned long)(((unsigned long *)stack)[0]);
-		pr_debug("other task rbp: %p\n", (void *)stack);
-	}
-
-	while (1) {
-		unsigned long stack_end = get_stack_end(task, stack);
-
-		pr_debug("stack:          %p\n", (void *)stack);
-		pr_debug("stack end:      %p\n", (void *)stack_end);
-
-		/*
-		 * Invalid stack addres?
-		 */
-		if (!stack_end)
-			return;
-		/*
-		 * Were we in this stack already? (recursion)
-		 */
-		for (i = 0; i < nr_stacks; i++)
-			if (stacks_done[i] == stack_end)
-				return;
-		stacks_done[nr_stacks] = stack_end;
-
-		stack = save_context_stack(trace, skip, stack, stack_end);
-		if (!all_contexts || !stack ||
-				trace->nr_entries >= trace->max_entries)
-			return;
-		trace->entries[trace->nr_entries++] = ULONG_MAX;
-		if (trace->nr_entries >= trace->max_entries)
-			return;
-		if (++nr_stacks >= MAX_STACKS)
-			return;
-	}
+	dump_trace(task, NULL, NULL, &save_stack_ops, trace);
+	trace->entries[trace->nr_entries++] = ULONG_MAX;
 }
+EXPORT_SYMBOL(save_stack_trace);