thread_info.h

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/*
 * OpenRISC Linux
 *
 * Linux architectural port borrowing liberally from similar works of
 * others.  All original copyrights apply as per the original source
 * declaration.
 *
 * OpenRISC implementation:
 * Copyright (C) 2003 Matjaz Breskvar <[email protected]>
 * Copyright (C) 2010-2011 Jonas Bonn <[email protected]>
 * et al.
 *
 * 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/types.h>
#include <asm/processor.h>
#endif


/* THREAD_SIZE is the size of the task_struct/kernel_stack combo.
 * normally, the stack is found by doing something like p + THREAD_SIZE
 * in or32, a page is 8192 bytes, which seems like a sane size
 */

#define THREAD_SIZE_ORDER 0
#define THREAD_SIZE       (PAGE_SIZE << THREAD_SIZE_ORDER)

/*
 * 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__

typedef unsigned long mm_segment_t;

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

    mm_segment_t        addr_limit; /* thread address space:
                           0-0x7FFFFFFF for user-thead
                           0-0xFFFFFFFF for kernel-thread
                         */
    struct restart_block    restart_block;
    __u8            supervisor_stack[0];

    /* saved context data */
    unsigned long           ksp;
};
#endif

/*
 * 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,  \
    },                      \
    .ksp            = 0,                            \
}

#define init_thread_info    (init_thread_union.thread_info)

/* how to get the thread information struct from C */
register struct thread_info *current_thread_info_reg asm("r10");
#define current_thread_info()   (current_thread_info_reg)

#define get_thread_info(ti) get_task_struct((ti)->task)
#define put_thread_info(ti) put_task_struct((ti)->task)

#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_SYSCALL_TRACEPOINT  8       /* for ftrace syscall instrumentation */
#define TIF_RESTORE_SIGMASK     9
#define TIF_POLLING_NRFLAG  16  /* true if poll_idle() is polling                        * TIF_NEED_RESCHED
                     */
#define TIF_MEMDIE              17

#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_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)


/* Work to do when returning from interrupt/exception */
/* For OpenRISC, this is anything in the LSW other than syscall trace */
#define _TIF_WORK_MASK (0xff & ~(_TIF_SYSCALL_TRACE|_TIF_SINGLESTEP))

#define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)

#endif /* __KERNEL__ */

#endif /* _ASM_THREAD_INFO_H */