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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
 */
#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; })

#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR

/* thread information allocation */
#ifdef CONFIG_DEBUG_STACK_USAGE
#define alloc_thread_info(tsk)                              \
      ({                                        \
            struct thread_info *ret;                  \
                                                \
            ret = kzalloc(THREAD_SIZE, GFP_KERNEL);         \
                                                \
            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     /* 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_POLLING_NRFLAG    16    /* true if poll_idle() is polling TIF_NEED_RESCHED */
#define TIF_MEMDIE            17    /* is terminating due to OOM killer */
#define TIF_FREEZE            18    /* freezing for suspend */

#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_RESTORE_SIGMASK  (1 << TIF_RESTORE_SIGMASK)
#define _TIF_POLLING_NRFLAG   (1 << TIF_POLLING_NRFLAG)
#define _TIF_FREEZE           (1 << TIF_FREEZE)

#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 */

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