1. 根目录:
2. arch
3. arm
4. include
5. asm
6. thread_info.h

/*
 *  arch/arm/include/asm/thread_info.h
 *
 *  Copyright (C) 2002 Russell King.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#ifndef __ASM_ARM_THREAD_INFO_H
#define __ASM_ARM_THREAD_INFO_H

#ifdef __KERNEL__

#include <linux/compiler.h>
#include <asm/fpstate.h>

#define THREAD_SIZE_ORDER	1
#define THREAD_SIZE		8192
#define THREAD_START_SP		(THREAD_SIZE - 8)

#ifndef __ASSEMBLY__

struct task_struct;
struct exec_domain;

#include <asm/types.h>
#include <asm/domain.h>

typedef unsigned long mm_segment_t;

struct cpu_context_save {
	__u32	r4;
	__u32	r5;
	__u32	r6;
	__u32	r7;
	__u32	r8;
	__u32	r9;
	__u32	sl;
	__u32	fp;
	__u32	sp;
	__u32	pc;
	__u32	extra[2];		/* Xscale 'acc' register, etc */
};

struct arm_restart_block {
	union {
		/* For user cache flushing */
		struct {
			unsigned long start;
			unsigned long end;
		} cache;
	};
};

/*
 * low level task data that entry.S needs immediate access to.
 * __switch_to() assumes cpu_context follows immediately after cpu_domain.
 */
struct thread_info {
	unsigned long		flags;		/* low level flags */
	int			preempt_count;	/* 0 => preemptable, <0 => bug */
	mm_segment_t		addr_limit;	/* address limit */
	struct task_struct	*task;		/* main task structure */
	struct exec_domain	*exec_domain;	/* execution domain */
	__u32			cpu;		/* cpu */
	__u32			cpu_domain;	/* cpu domain */
	struct cpu_context_save	cpu_context;	/* cpu context */
	__u32			syscall;	/* syscall number */
	__u8			used_cp[16];	/* thread used copro */
	unsigned long		tp_value[2];	/* TLS registers */
#ifdef CONFIG_CRUNCH
	struct crunch_state	crunchstate;
#endif
	union fp_state		fpstate __attribute__((aligned(8)));
	union vfp_state		vfpstate;
#ifdef CONFIG_ARM_THUMBEE
	unsigned long		thumbee_state;	/* ThumbEE Handler Base register */
#endif
	struct restart_block	restart_block;
	struct arm_restart_block	arm_restart_block;
};

#define INIT_THREAD_INFO(tsk)						\
{									\
	.task		= &tsk,						\
	.exec_domain	= &default_exec_domain,				\
	.flags		= 0,						\
	.preempt_count	= INIT_PREEMPT_COUNT,				\
	.addr_limit	= KERNEL_DS,					\
	.cpu_domain	= domain_val(DOMAIN_USER, DOMAIN_MANAGER) |	\
			  domain_val(DOMAIN_KERNEL, DOMAIN_MANAGER) |	\
			  domain_val(DOMAIN_IO, DOMAIN_CLIENT),		\
	.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
 */
static inline struct thread_info *current_thread_info(void) __attribute_const__;

static inline struct thread_info *current_thread_info(void)
{
	register unsigned long sp asm ("sp");
	return (struct thread_info *)(sp & ~(THREAD_SIZE - 1));
}

#define thread_saved_pc(tsk)	\
	((unsigned long)(task_thread_info(tsk)->cpu_context.pc))
#define thread_saved_sp(tsk)	\
	((unsigned long)(task_thread_info(tsk)->cpu_context.sp))
#define thread_saved_fp(tsk)	\
	((unsigned long)(task_thread_info(tsk)->cpu_context.fp))

extern void crunch_task_disable(struct thread_info *);
extern void crunch_task_copy(struct thread_info *, void *);
extern void crunch_task_restore(struct thread_info *, void *);
extern void crunch_task_release(struct thread_info *);

extern void iwmmxt_task_disable(struct thread_info *);
extern void iwmmxt_task_copy(struct thread_info *, void *);
extern void iwmmxt_task_restore(struct thread_info *, void *);
extern void iwmmxt_task_release(struct thread_info *);
extern void iwmmxt_task_switch(struct thread_info *);

extern void vfp_sync_hwstate(struct thread_info *);
extern void vfp_flush_hwstate(struct thread_info *);

struct user_vfp;
struct user_vfp_exc;

extern int vfp_preserve_user_clear_hwstate(struct user_vfp __user *,
					   struct user_vfp_exc __user *);
extern int vfp_restore_user_hwstate(struct user_vfp __user *,
				    struct user_vfp_exc __user *);
#endif

/*
 * thread information flags:
 *  TIF_SYSCALL_TRACE	- syscall trace active
 *  TIF_SYSCAL_AUDIT	- syscall auditing active
 *  TIF_SIGPENDING	- signal pending
 *  TIF_NEED_RESCHED	- rescheduling necessary
 *  TIF_NOTIFY_RESUME	- callback before returning to user
 *  TIF_USEDFPU		- FPU was used by this task this quantum (SMP)
 *  TIF_POLLING_NRFLAG	- true if poll_idle() is polling TIF_NEED_RESCHED
 */
#define TIF_SIGPENDING		0
#define TIF_NEED_RESCHED	1
#define TIF_NOTIFY_RESUME	2	/* callback before returning to user */
#define TIF_SYSCALL_TRACE	8
#define TIF_SYSCALL_AUDIT	9
#define TIF_SYSCALL_TRACEPOINT	10
#define TIF_SECCOMP		11	/* seccomp syscall filtering active */
#define TIF_NOHZ		12	/* in adaptive nohz mode */
#define TIF_USING_IWMMXT	17
#define TIF_MEMDIE		18	/* is terminating due to OOM killer */
#define TIF_RESTORE_SIGMASK	20

#define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
#define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
#define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)
#define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
#define _TIF_SYSCALL_AUDIT	(1 << TIF_SYSCALL_AUDIT)
#define _TIF_SYSCALL_TRACEPOINT	(1 << TIF_SYSCALL_TRACEPOINT)
#define _TIF_SECCOMP		(1 << TIF_SECCOMP)
#define _TIF_USING_IWMMXT	(1 << TIF_USING_IWMMXT)

/* Checks for any syscall work in entry-common.S */
#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
			   _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP)

/*
 * Change these and you break ASM code in entry-common.S
 */
#define _TIF_WORK_MASK		(_TIF_NEED_RESCHED | _TIF_SIGPENDING | _TIF_NOTIFY_RESUME)

#endif /* __KERNEL__ */
#endif /* __ASM_ARM_THREAD_INFO_H */