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Commit f3ac6067 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

sched/headers: Move task-stack related APIs from <linux/sched.h> to <linux/sched/task_stack.h> 



Split out the task->stack related functionality, which is not really
part of the core scheduler APIs.

Only keep task_thread_info() because it's used by sched.h.

Update the code that uses those facilities.

Acked-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent d04b0ad3

arch/mips/kernel/smp-cps.c

+1 −1
Original line number Diff line number Diff line
@@ -11,7 +11,7 @@ 
#include <linux/delay.h>

#include <linux/io.h>

#include <linux/irqchip/mips-gic.h>

#include <linux/sched.h>

#include <linux/sched/task_stack.h>

#include <linux/sched/hotplug.h>

#include <linux/slab.h>

#include <linux/smp.h>

arch/mips/sibyte/sb1250/smp.c

+1 −1
Original line number Diff line number Diff line
@@ -21,7 +21,7 @@ 
#include <linux/interrupt.h>

#include <linux/smp.h>

#include <linux/kernel_stat.h>

#include <linux/sched.h>

#include <linux/sched/task_stack.h>



#include <asm/mmu_context.h>

#include <asm/io.h>

include/linux/sched.h

+9 −106
Original line number Diff line number Diff line
@@ -1450,6 +1450,15 @@ union thread_union { 
	unsigned long stack[THREAD_SIZE/sizeof(long)];

};



#ifdef CONFIG_THREAD_INFO_IN_TASK

static inline struct thread_info *task_thread_info(struct task_struct *task)

{

	return &task->thread_info;

}

#elif !defined(__HAVE_THREAD_FUNCTIONS)

# define task_thread_info(task)	((struct thread_info *)(task)->stack)

#endif



#ifndef __HAVE_ARCH_KSTACK_END

static inline int kstack_end(void *addr)

{
@@ -1540,112 +1549,6 @@ static inline void task_unlock(struct task_struct *p) 
	spin_unlock(&p->alloc_lock);

}



#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)	((void *)(task)->stack)



static inline void setup_thread_stack(struct task_struct *p, struct task_struct *org)

{

	*task_thread_info(p) = *task_thread_info(org);

	task_thread_info(p)->task = p;

}



/*

 * Return the address of the last usable long on the stack.

 *

 * When the stack grows down, this is just above the thread

 * info struct. Going any lower will corrupt the threadinfo.

 *

 * When the stack grows up, this is the highest address.

 * Beyond that position, we corrupt data on the next page.

 */

static inline unsigned long *end_of_stack(struct task_struct *p)

{

#ifdef CONFIG_STACK_GROWSUP

	return (unsigned long *)((unsigned long)task_thread_info(p) + THREAD_SIZE) - 1;

#else

	return (unsigned long *)(task_thread_info(p) + 1);

#endif

}



#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)



static inline int object_is_on_stack(void *obj)

{

	void *stack = task_stack_page(current);



	return (obj >= stack) && (obj < (stack + THREAD_SIZE));

}



extern void thread_stack_cache_init(void);



#ifdef CONFIG_DEBUG_STACK_USAGE

static inline unsigned long stack_not_used(struct task_struct *p)

{

	unsigned long *n = end_of_stack(p);



	do { 	/* Skip over canary */

# ifdef CONFIG_STACK_GROWSUP

		n--;

# else

		n++;

# endif

	} while (!*n);



# ifdef CONFIG_STACK_GROWSUP

	return (unsigned long)end_of_stack(p) - (unsigned long)n;

# else

	return (unsigned long)n - (unsigned long)end_of_stack(p);

# endif

}

#endif

extern void set_task_stack_end_magic(struct task_struct *tsk);



/* set thread flags in other task's structures

 * - see asm/thread_info.h for TIF_xxxx flags available

 */

include/linux/sched/task_stack.h

+104 −0
Original line number Diff line number Diff line 
#ifndef _LINUX_SCHED_TASK_STACK_H

#define _LINUX_SCHED_TASK_STACK_H



/*

 * task->stack (kernel stack) handling interfaces:

 */



#include <linux/sched.h>

#include <linux/magic.h>



#ifdef CONFIG_THREAD_INFO_IN_TASK



/*

 * 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_stack_page(task)	((void *)(task)->stack)



static inline void setup_thread_stack(struct task_struct *p, struct task_struct *org)

{

	*task_thread_info(p) = *task_thread_info(org);

	task_thread_info(p)->task = p;

}



/*

 * Return the address of the last usable long on the stack.

 *

 * When the stack grows down, this is just above the thread

 * info struct. Going any lower will corrupt the threadinfo.

 *

 * When the stack grows up, this is the highest address.

 * Beyond that position, we corrupt data on the next page.

 */

static inline unsigned long *end_of_stack(struct task_struct *p)

{

#ifdef CONFIG_STACK_GROWSUP

	return (unsigned long *)((unsigned long)task_thread_info(p) + THREAD_SIZE) - 1;

#else

	return (unsigned long *)(task_thread_info(p) + 1);

#endif

}



#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)



static inline int object_is_on_stack(void *obj)

{

	void *stack = task_stack_page(current);



	return (obj >= stack) && (obj < (stack + THREAD_SIZE));

}



extern void thread_stack_cache_init(void);



#ifdef CONFIG_DEBUG_STACK_USAGE

static inline unsigned long stack_not_used(struct task_struct *p)

{

	unsigned long *n = end_of_stack(p);



	do { 	/* Skip over canary */

# ifdef CONFIG_STACK_GROWSUP

		n--;

# else

		n++;

# endif

	} while (!*n);



# ifdef CONFIG_STACK_GROWSUP

	return (unsigned long)end_of_stack(p) - (unsigned long)n;

# else

	return (unsigned long)n - (unsigned long)end_of_stack(p);

# endif

}

#endif

extern void set_task_stack_end_magic(struct task_struct *tsk);



#endif /* _LINUX_SCHED_TASK_STACK_H */