1 files changed, 130 insertions, 0 deletions
diff --git a/arch/x86/kernel/stacktrace.c b/arch/x86/kernel/stacktrace.c
new file mode 100644
index 0000000000..ee117fcf46
--- /dev/null
+++ b/arch/x86/kernel/stacktrace.c
@@ -0,0 +1,130 @@
+/*
+ * Stack trace management functions
+ *
+ *  Copyright (C) 2006-2009 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ */
+#include <linux/sched.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/task_stack.h>
+#include <linux/stacktrace.h>
+#include <linux/export.h>
+#include <linux/uaccess.h>
+#include <asm/stacktrace.h>
+#include <asm/unwind.h>
+
+void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
+		     struct task_struct *task, struct pt_regs *regs)
+{
+	struct unwind_state state;
+	unsigned long addr;
+
+	if (regs && !consume_entry(cookie, regs->ip))
+		return;
+
+	for (unwind_start(&state, task, regs, NULL); !unwind_done(&state);
+	     unwind_next_frame(&state)) {
+		addr = unwind_get_return_address(&state);
+		if (!addr || !consume_entry(cookie, addr))
+			break;
+	}
+}
+
+int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry,
+			     void *cookie, struct task_struct *task)
+{
+	struct unwind_state state;
+	struct pt_regs *regs;
+	unsigned long addr;
+
+	for (unwind_start(&state, task, NULL, NULL);
+	     !unwind_done(&state) && !unwind_error(&state);
+	     unwind_next_frame(&state)) {
+
+		regs = unwind_get_entry_regs(&state, NULL);
+		if (regs) {
+			/* Success path for user tasks */
+			if (user_mode(regs))
+				return 0;
+
+			/*
+			 * Kernel mode registers on the stack indicate an
+			 * in-kernel interrupt or exception (e.g., preemption
+			 * or a page fault), which can make frame pointers
+			 * unreliable.
+			 */
+			if (IS_ENABLED(CONFIG_FRAME_POINTER))
+				return -EINVAL;
+		}
+
+		addr = unwind_get_return_address(&state);
+
+		/*
+		 * A NULL or invalid return address probably means there's some
+		 * generated code which __kernel_text_address() doesn't know
+		 * about.
+		 */
+		if (!addr)
+			return -EINVAL;
+
+		if (!consume_entry(cookie, addr))
+			return -EINVAL;
+	}
+
+	/* Check for stack corruption */
+	if (unwind_error(&state))
+		return -EINVAL;
+
+	return 0;
+}
+
+/* Userspace stacktrace - based on kernel/trace/trace_sysprof.c */
+
+struct stack_frame_user {
+	const void __user	*next_fp;
+	unsigned long		ret_addr;
+};
+
+static int
+copy_stack_frame(const struct stack_frame_user __user *fp,
+		 struct stack_frame_user *frame)
+{
+	int ret;
+
+	if (!__access_ok(fp, sizeof(*frame)))
+		return 0;
+
+	ret = 1;
+	pagefault_disable();
+	if (__get_user(frame->next_fp, &fp->next_fp) ||
+	    __get_user(frame->ret_addr, &fp->ret_addr))
+		ret = 0;
+	pagefault_enable();
+
+	return ret;
+}
+
+void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie,
+			  const struct pt_regs *regs)
+{
+	const void __user *fp = (const void __user *)regs->bp;
+
+	if (!consume_entry(cookie, regs->ip))
+		return;
+
+	while (1) {
+		struct stack_frame_user frame;
+
+		frame.next_fp = NULL;
+		frame.ret_addr = 0;
+		if (!copy_stack_frame(fp, &frame))
+			break;
+		if ((unsigned long)fp < regs->sp)
+			break;
+		if (!frame.ret_addr)
+			break;
+		if (!consume_entry(cookie, frame.ret_addr))
+			break;
+		fp = frame.next_fp;
+	}
+}
+