thread_info.h

/* thread_info.h: description
 *
 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 * Derived from include/asm-i386/thread_info.h
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#ifndef _ASM_THREAD_INFO_H
#define _ASM_THREAD_INFO_H

#ifdef __KERNEL__

#ifndef __ASSEMBLY__
#include <asm/processor.h>
#endif

#define THREAD_SIZE		8192

/*
 * low level task data that entry.S needs immediate access to
 * - this struct should fit entirely inside of one cache line
 * - this struct shares the supervisor stack pages
 * - if the contents of this structure are changed, the assembly constants must also be changed
 */
#ifndef __ASSEMBLY__

struct thread_info {
	struct task_struct	*task;		/* main task structure */
	struct exec_domain	*exec_domain;	/* execution domain */
	unsigned long		flags;		/* low level flags */
	unsigned long		status;		/* thread-synchronous flags */
	__u32			cpu;		/* current CPU */
	int			preempt_count;	/* 0 => preemptable, <0 => BUG */

	mm_segment_t		addr_limit;	/* thread address space:
					 	   0-0xBFFFFFFF for user-thead
						   0-0xFFFFFFFF for kernel-thread
						*/
	struct restart_block    restart_block;

	__u8			supervisor_stack[0];
};

#else /* !__ASSEMBLY__ */

#include <asm/asm-offsets.h>

#endif

#define PREEMPT_ACTIVE		0x10000000

/*
 * macros/functions for gaining access to the thread information structure
 *
 * preempt_count needs to be 1 initially, until the scheduler is functional.
 */
#ifndef __ASSEMBLY__

#define INIT_THREAD_INFO(tsk)			\
{						\
	.task		= &tsk,			\
	.exec_domain	= &default_exec_domain,	\
	.flags		= 0,			\
	.cpu		= 0,			\
	.preempt_count	= 1,			\
	.addr_limit	= KERNEL_DS,		\
	.restart_block = {			\
		.fn = do_no_restart_syscall,	\
	},					\
}

#define init_thread_info	(init_thread_union.thread_info)
#define init_stack		(init_thread_union.stack)

/* how to get the thread information struct from C */
register struct thread_info *__current_thread_info asm("gr15");

#define current_thread_info() ({ __current_thread_info; })

/* thread information allocation */
#ifdef CONFIG_DEBUG_STACK_USAGE
#define alloc_thread_info(tsk)					\
	({							\
		struct thread_info *ret;			\
								\
		ret = kmalloc(THREAD_SIZE, GFP_KERNEL);		\
		if (ret)					\
			memset(ret, 0, THREAD_SIZE);		\
		ret;						\
	})
#else
#define alloc_thread_info(tsk)	kmalloc(THREAD_SIZE, GFP_KERNEL)
#endif

#define free_thread_info(info)	kfree(info)

#endif /* __ASSEMBLY__ */

/*
 * thread information flags
 * - these are process state flags that various assembly files may need to access
 * - pending work-to-be-done flags are in LSW
 * - other flags in MSW
 */
#define TIF_SYSCALL_TRACE	0	/* syscall trace active */
#define TIF_NOTIFY_RESUME	1	/* resumption notification requested */
#define TIF_SIGPENDING		2	/* signal pending */
#define TIF_NEED_RESCHED	3	/* rescheduling necessary */
#define TIF_SINGLESTEP		4	/* restore singlestep on return to user mode */
#define TIF_IRET		5	/* return with iret */
#define TIF_RESTORE_SIGMASK	6	/* restore signal mask in do_signal() */
#define TIF_POLLING_NRFLAG	16	/* true if poll_idle() is polling TIF_NEED_RESCHED */
#define TIF_MEMDIE		17	/* OOM killer killed process */

#define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
#define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)
#define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
#define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
#define _TIF_SINGLESTEP		(1 << TIF_SINGLESTEP)
#define _TIF_IRET		(1 << TIF_IRET)
#define _TIF_RESTORE_SIGMASK	(1 << TIF_RESTORE_SIGMASK)
#define _TIF_POLLING_NRFLAG	(1 << TIF_POLLING_NRFLAG)

#define _TIF_WORK_MASK		0x0000FFFE	/* work to do on interrupt/exception return */
#define _TIF_ALLWORK_MASK	0x0000FFFF	/* work to do on any return to u-space */

/*
 * Thread-synchronous status.
 *
 * This is different from the flags in that nobody else
 * ever touches our thread-synchronous status, so we don't
 * have to worry about atomic accesses.
 */
#define TS_USEDFPM		0x0001	/* FPU/Media was used by this task this quantum (SMP) */

#endif /* __KERNEL__ */

#endif /* _ASM_THREAD_INFO_H */