thread_info.h

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/*
 * Copyright 2004-2010 Analog Devices Inc.
 *
 * Licensed under the GPL-2 or later.
 */

#ifndef _ASM_THREAD_INFO_H
#define _ASM_THREAD_INFO_H

#include <asm/page.h>
#include <asm/entry.h>
#include <asm/l1layout.h>
#include <linux/compiler.h>

#ifdef __KERNEL__

/* Thread Align Mask to reach to the top of the stack
 * for any process
 */
#define ALIGN_PAGE_MASK     0xffffe000

/*
 * Size of kernel stack for each process. This must be a power of 2...
 */
#define THREAD_SIZE_ORDER   1
#define THREAD_SIZE     8192    /* 2 pages */
#define STACK_WARN      (THREAD_SIZE/8)

#ifndef __ASSEMBLY__

typedef unsigned long mm_segment_t;

/*
 * low level task data.
 * If you change this, change the TI_* offsets below to match.
 */

struct thread_info {
    struct task_struct *task;   /* main task structure */
    struct exec_domain *exec_domain;    /* execution domain */
    unsigned long flags;    /* low level flags */
    int cpu;        /* cpu we're on */
    int preempt_count;  /* 0 => preemptable, <0 => BUG */
    mm_segment_t addr_limit;    /* address limit */
    struct restart_block restart_block;
#ifndef CONFIG_SMP
    struct l1_scratch_task_info l1_task_info;
#endif
};

/*
 * macros/functions for gaining access to the thread information structure
 */
#define INIT_THREAD_INFO(tsk)           \
{                       \
    .task       = &tsk,         \
    .exec_domain    = &default_exec_domain, \
    .flags      = 0,            \
    .cpu        = 0,            \
    .preempt_count  = INIT_PREEMPT_COUNT,   \
    .restart_block  = {         \
        .fn = do_no_restart_syscall,    \
    },                  \
}
#define init_thread_info    (init_thread_union.thread_info)
#define init_stack      (init_thread_union.stack)

/* Given a task stack pointer, you can find its corresponding
 * thread_info structure just by masking it to the THREAD_SIZE
 * boundary (currently 8K as you can see above).
 */
__attribute_const__
static inline struct thread_info *current_thread_info(void)
{
    struct thread_info *ti;
    __asm__("%0 = sp;" : "=da"(ti));
    return (struct thread_info *)((long)ti & ~((long)THREAD_SIZE-1));
}

#endif              /* __ASSEMBLY__ */

/*
 * Offsets in thread_info structure, used in assembly code
 */
#define TI_TASK     0
#define TI_EXECDOMAIN   4
#define TI_FLAGS    8
#define TI_CPU      12
#define TI_PREEMPT  16

#define PREEMPT_ACTIVE  0x4000000

/*
 * thread information flag bit numbers
 */
#define TIF_SYSCALL_TRACE   0   /* syscall trace active */
#define TIF_SIGPENDING      1   /* signal pending */
#define TIF_NEED_RESCHED    2   /* rescheduling necessary */
#define TIF_MEMDIE      4   /* is terminating due to OOM killer */
#define TIF_RESTORE_SIGMASK 5   /* restore signal mask in do_signal() */
#define TIF_IRQ_SYNC        7   /* sync pipeline stage */
#define TIF_NOTIFY_RESUME   8   /* callback before returning to user */
#define TIF_SINGLESTEP      9

/* as above, but as bit values */
#define _TIF_SYSCALL_TRACE  (1<<TIF_SYSCALL_TRACE)
#define _TIF_SIGPENDING     (1<<TIF_SIGPENDING)
#define _TIF_NEED_RESCHED   (1<<TIF_NEED_RESCHED)
#define _TIF_IRQ_SYNC       (1<<TIF_IRQ_SYNC)
#define _TIF_NOTIFY_RESUME  (1<<TIF_NOTIFY_RESUME)
#define _TIF_SINGLESTEP     (1<<TIF_SINGLESTEP)

#define _TIF_WORK_MASK      0x0000FFFE  /* work to do on interrupt/exception return */

#endif              /* __KERNEL__ */

#endif              /* _ASM_THREAD_INFO_H */