thread_info.h

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/*
 * Based on arch/arm/include/asm/thread_info.h
 *
 * Copyright (C) 2002 Russell King.
 * Copyright (C) 2012 ARM Ltd.
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#ifndef __ASM_THREAD_INFO_H
#define __ASM_THREAD_INFO_H

#ifdef __KERNEL__

#include <linux/compiler.h>

#ifndef CONFIG_ARM64_64K_PAGES
#define THREAD_SIZE_ORDER   1
#endif

#define THREAD_SIZE     8192
#define THREAD_START_SP     (THREAD_SIZE - 16)

#ifndef __ASSEMBLY__

struct task_struct;
struct exec_domain;

#include <asm/types.h>

typedef unsigned long mm_segment_t;

/*
 * 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 */
    mm_segment_t        addr_limit; /* address limit */
    struct task_struct  *task;      /* main task structure */
    struct exec_domain  *exec_domain;   /* execution domain */
    struct restart_block    restart_block;
    int         preempt_count;  /* 0 => preemptable, <0 => bug */
    int         cpu;        /* cpu */
};

#define INIT_THREAD_INFO(tsk)                       \
{                                   \
    .task       = &tsk,                     \
    .exec_domain    = &default_exec_domain,             \
    .flags      = 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
 */
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)(tsk->thread.cpu_context.pc))
#define thread_saved_sp(tsk)    \
    ((unsigned long)(tsk->thread.cpu_context.sp))
#define thread_saved_fp(tsk)    \
    ((unsigned long)(tsk->thread.cpu_context.fp))

#endif

/*
 * We use bit 30 of the preempt_count to indicate that kernel
 * preemption is occurring.  See <asm/hardirq.h>.
 */
#define PREEMPT_ACTIVE  0x40000000

/*
 * thread information flags:
 *  TIF_SYSCALL_TRACE   - syscall trace 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_POLLING_NRFLAG  16
#define TIF_MEMDIE      18  /* is terminating due to OOM killer */
#define TIF_FREEZE      19
#define TIF_RESTORE_SIGMASK 20
#define TIF_SINGLESTEP      21
#define TIF_32BIT       22  /* 32bit process */
#define TIF_SWITCH_MM       23  /* deferred switch_mm */

#define _TIF_SIGPENDING     (1 << TIF_SIGPENDING)
#define _TIF_NEED_RESCHED   (1 << TIF_NEED_RESCHED)
#define _TIF_NOTIFY_RESUME  (1 << TIF_NOTIFY_RESUME)
#define _TIF_32BIT      (1 << TIF_32BIT)

#define _TIF_WORK_MASK      (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
                 _TIF_NOTIFY_RESUME)

#endif /* __KERNEL__ */
#endif /* __ASM_THREAD_INFO_H */