lkl: make object_is_on_stack() check host thread stacks

arch/lkl/include/asm/thread_info.h

@@ -8,6 +8,23 @@
 #include <asm/processor.h>
 #include <asm/host_ops.h>
 
+#define __HAVE_ARCH_OBJECT_IS_ON_STACK
+static inline int arch_object_is_on_stack(const void *obj)
+{
+	unsigned long addr = (unsigned long)obj;
+	unsigned long stack_size;
+	unsigned long stack;
+
+	if (!lkl_ops || !lkl_ops->thread_stack)
+		return 0;
+
+	stack = (unsigned long)lkl_ops->thread_stack(&stack_size);
+	if (!stack)
+		return 0;
+
+	return addr >= stack && addr - stack < stack_size;
+}
+
 struct thread_info {
 	struct task_struct *task;
 	unsigned long flags;

include/linux/sched/task_stack.h

@@ -88,10 +88,17 @@ void exit_task_stack_account(struct task_struct *tsk);
 
 static inline int object_is_on_stack(const void *obj)
 {
+#ifndef __HAVE_ARCH_OBJECT_IS_ON_STACK
 	void *stack = task_stack_page(current);
+#endif
 
 	obj = kasan_reset_tag(obj);
+
+#ifdef __HAVE_ARCH_OBJECT_IS_ON_STACK
+	return arch_object_is_on_stack(obj);
+#else
 	return (obj >= stack) && (obj < (stack + THREAD_SIZE));
+#endif
 }
 
 extern void thread_stack_cache_init(void);