thread_info.h

/*
 * include/asm-xtensa/thread_info.h
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2001 - 2005 Tensilica Inc.
 */

#ifndef _XTENSA_THREAD_INFO_H
#define _XTENSA_THREAD_INFO_H

#ifdef __KERNEL__

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

/*
 * 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__

#if XTENSA_HAVE_COPROCESSORS

typedef struct xtregs_coprocessor {
	xtregs_cp0_t cp0;
	xtregs_cp1_t cp1;
	xtregs_cp2_t cp2;
	xtregs_cp3_t cp3;
	xtregs_cp4_t cp4;
	xtregs_cp5_t cp5;
	xtregs_cp6_t cp6;
	xtregs_cp7_t cp7;
} xtregs_coprocessor_t;

#endif

struct thread_info {
	struct task_struct	*task;		/* main task structure */
	unsigned long		flags;		/* low level flags */
	unsigned long		status;		/* thread-synchronous flags */
	__u32			cpu;		/* current CPU */
	__s32			preempt_count;	/* 0 => preemptable,< 0 => BUG*/

	mm_segment_t		addr_limit;	/* thread address space */

	unsigned long		cpenable;

	/* Allocate storage for extra user states and coprocessor states. */
#if XTENSA_HAVE_COPROCESSORS
	xtregs_coprocessor_t	xtregs_cp;
#endif
	xtregs_user_t		xtregs_user;
};

#endif

/*
 * macros/functions for gaining access to the thread information structure
 */

#ifndef __ASSEMBLY__

#define INIT_THREAD_INFO(tsk)			\
{						\
	.task		= &tsk,			\
	.flags		= 0,			\
	.cpu		= 0,			\
	.preempt_count	= INIT_PREEMPT_COUNT,	\
	.addr_limit	= KERNEL_DS,		\
}

#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 */
static inline struct thread_info *current_thread_info(void)
{
	struct thread_info *ti;
	 __asm__("extui %0,a1,0,13\n\t"
	         "xor %0, a1, %0" : "=&r" (ti) : );
	return ti;
}

#else /* !__ASSEMBLY__ */

/* how to get the thread information struct from ASM */
#define GET_THREAD_INFO(reg,sp) \
	extui reg, sp, 0, 13; \
	xor   reg, sp, reg
#endif


/*
 * 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_SIGPENDING		1	/* signal pending */
#define TIF_NEED_RESCHED	2	/* rescheduling necessary */
#define TIF_SINGLESTEP		3	/* restore singlestep on return to user mode */
#define TIF_MEMDIE		5	/* is terminating due to OOM killer */
#define TIF_RESTORE_SIGMASK	6	/* restore signal mask in do_signal() */
#define TIF_NOTIFY_RESUME	7	/* callback before returning to user */
#define TIF_DB_DISABLED		8	/* debug trap disabled for syscall */

#define _TIF_SYSCALL_TRACE	(1<<TIF_SYSCALL_TRACE)
#define _TIF_SIGPENDING		(1<<TIF_SIGPENDING)
#define _TIF_NEED_RESCHED	(1<<TIF_NEED_RESCHED)
#define _TIF_SINGLESTEP		(1<<TIF_SINGLESTEP)

#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_USEDFPU		0x0001	/* FPU was used by this task this quantum (SMP) */

#define THREAD_SIZE 8192	//(2*PAGE_SIZE)
#define THREAD_SIZE_ORDER 1

#endif	/* __KERNEL__ */
#endif	/* _XTENSA_THREAD_INFO */