1 files changed, 79 insertions, 2 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index f76d75fc9eaf..7543a476178b 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1471,6 +1471,13 @@ struct tlbflush_unmap_batch {
 };
 
 struct task_struct {
+#ifdef CONFIG_THREAD_INFO_IN_TASK
+	/*
+	 * For reasons of header soup (see current_thread_info()), this
+	 * must be the first element of task_struct.
+	 */
+	struct thread_info thread_info;
+#endif
 	volatile long state;	/* -1 unrunnable, 0 runnable, >0 stopped */
 	void *stack;
 	atomic_t usage;
@@ -1480,6 +1487,9 @@ struct task_struct {
 #ifdef CONFIG_SMP
 	struct llist_node wake_entry;
 	int on_cpu;
+#ifdef CONFIG_THREAD_INFO_IN_TASK
+	unsigned int cpu;	/* current CPU */
+#endif
 	unsigned int wakee_flips;
 	unsigned long wakee_flip_decay_ts;
 	struct task_struct *last_wakee;
@@ -1936,6 +1946,13 @@ struct task_struct {
 #ifdef CONFIG_MMU
 	struct task_struct *oom_reaper_list;
 #endif
+#ifdef CONFIG_VMAP_STACK
+	struct vm_struct *stack_vm_area;
+#endif
+#ifdef CONFIG_THREAD_INFO_IN_TASK
+	/* A live task holds one reference. */
+	atomic_t stack_refcount;
+#endif
 /* CPU-specific state of this task */
 	struct thread_struct thread;
 /*
@@ -1952,6 +1969,18 @@ extern int arch_task_struct_size __read_mostly;
 # define arch_task_struct_size (sizeof(struct task_struct))
 #endif
 
+#ifdef CONFIG_VMAP_STACK
+static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
+{
+	return t->stack_vm_area;
+}
+#else
+static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
+{
+	return NULL;
+}
+#endif
+
 /* Future-safe accessor for struct task_struct's cpus_allowed. */
 #define tsk_cpus_allowed(tsk) (&(tsk)->cpus_allowed)
 
@@ -2586,7 +2615,9 @@ extern void ia64_set_curr_task(int cpu, struct task_struct *p);
 void yield(void);
 
 union thread_union {
+#ifndef CONFIG_THREAD_INFO_IN_TASK
 	struct thread_info thread_info;
+#endif
 	unsigned long stack[THREAD_SIZE/sizeof(long)];
 };
 
@@ -3074,10 +3105,34 @@ static inline void threadgroup_change_end(struct task_struct *tsk)
 	cgroup_threadgroup_change_end(tsk);
 }
 
-#ifndef __HAVE_THREAD_FUNCTIONS
+#ifdef CONFIG_THREAD_INFO_IN_TASK
+
+static inline struct thread_info *task_thread_info(struct task_struct *task)
+{
+	return &task->thread_info;
+}
+
+/*
+ * When accessing the stack of a non-current task that might exit, use
+ * try_get_task_stack() instead.  task_stack_page will return a pointer
+ * that could get freed out from under you.
+ */
+static inline void *task_stack_page(const struct task_struct *task)
+{
+	return task->stack;
+}
+
+#define setup_thread_stack(new,old)	do { } while(0)
+
+static inline unsigned long *end_of_stack(const struct task_struct *task)
+{
+	return task->stack;
+}
+
+#elif !defined(__HAVE_THREAD_FUNCTIONS)
 
 #define task_thread_info(task)	((struct thread_info *)(task)->stack)
-#define task_stack_page(task)	((task)->stack)
+#define task_stack_page(task)	((void *)(task)->stack)
 
 static inline void setup_thread_stack(struct task_struct *p, struct task_struct *org)
 {
@@ -3104,6 +3159,24 @@ static inline unsigned long *end_of_stack(struct task_struct *p)
 }
 
 #endif
+
+#ifdef CONFIG_THREAD_INFO_IN_TASK
+static inline void *try_get_task_stack(struct task_struct *tsk)
+{
+	return atomic_inc_not_zero(&tsk->stack_refcount) ?
+		task_stack_page(tsk) : NULL;
+}
+
+extern void put_task_stack(struct task_struct *tsk);
+#else
+static inline void *try_get_task_stack(struct task_struct *tsk)
+{
+	return task_stack_page(tsk);
+}
+
+static inline void put_task_stack(struct task_struct *tsk) {}
+#endif
+
 #define task_stack_end_corrupted(task) \
 		(*(end_of_stack(task)) != STACK_END_MAGIC)
 
@@ -3390,7 +3463,11 @@ static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
 
 static inline unsigned int task_cpu(const struct task_struct *p)
 {
+#ifdef CONFIG_THREAD_INFO_IN_TASK
+	return p->cpu;
+#else
 	return task_thread_info(p)->cpu;
+#endif
 }
 
 static inline int task_node(const struct task_struct *p)