thread_info.h

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/* thread_info.h: description
 *
 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 * 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
 */
#ifndef __ASSEMBLY__

#define INIT_THREAD_INFO(tsk)           \
{                       \
    .task       = &tsk,         \
    .exec_domain    = &default_exec_domain, \
    .flags      = 0,            \
    .cpu        = 0,            \
    .preempt_count  = INIT_PREEMPT_COUNT,   \
    .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; })

#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   /* callback before returning to user */
#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_RESTORE_SIGMASK 5   /* restore signal mask in do_signal() */
#define TIF_MEMDIE      7   /* is terminating due to OOM killer */

#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)

/* work to do on interrupt/exception return */
#define _TIF_WORK_MASK      \
    (_TIF_NOTIFY_RESUME | _TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_SINGLESTEP)

/* work to do on any return to u-space */
#define _TIF_ALLWORK_MASK   (_TIF_WORK_MASK | _TIF_SYSCALL_TRACE)

#if _TIF_ALLWORK_MASK >= 0x2000
#error "_TIF_ALLWORK_MASK won't fit in an ANDI now (see entry.S)"
#endif

/*
 * 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 */