thread_info.h

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/* MN10300 Low-level thread information
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */

#ifndef _ASM_THREAD_INFO_H
#define _ASM_THREAD_INFO_H

#ifdef __KERNEL__

#include <asm/page.h>

#define PREEMPT_ACTIVE      0x10000000

#ifdef CONFIG_4KSTACKS
#define THREAD_SIZE     (4096)
#define THREAD_SIZE_ORDER   (0)
#else
#define THREAD_SIZE     (8192)
#define THREAD_SIZE_ORDER   (1)
#endif

#define STACK_WARN      (THREAD_SIZE / 8)

/*
 * 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 struct {
    unsigned long   seg;
} mm_segment_t;

struct thread_info {
    struct task_struct  *task;      /* main task structure */
    struct exec_domain  *exec_domain;   /* execution domain */
    struct pt_regs      *frame;     /* current exception frame */
    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:
                           0-0xBFFFFFFF for user-thead
                           0-0xFFFFFFFF for kernel-thread
                        */
    struct restart_block    restart_block;

    __u8            supervisor_stack[0];
};

#define thread_info_to_uregs(ti)                    \
    ((struct pt_regs *)                     \
     ((unsigned long)ti + THREAD_SIZE - sizeof(struct pt_regs)))

#else /* !__ASSEMBLY__ */

#ifndef __ASM_OFFSETS_H__
#include <asm/asm-offsets.h>
#endif

#endif

/*
 * 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)
#define init_uregs                          \
    ((struct pt_regs *)                     \
     ((unsigned long) init_stack + THREAD_SIZE - sizeof(struct pt_regs)))

extern struct thread_info *__current_ti;

/* how to get the thread information struct from C */
static inline __attribute__((const))
struct thread_info *current_thread_info(void)
{
    struct thread_info *ti;
    asm("mov sp,%0\n"
        "and %1,%0\n"
        : "=d" (ti)
        : "i" (~(THREAD_SIZE - 1))
        : "cc");
    return ti;
}

static inline __attribute__((const))
struct pt_regs *current_frame(void)
{
    return current_thread_info()->frame;
}

/* how to get the current stack pointer from C */
static inline unsigned long current_stack_pointer(void)
{
    unsigned long sp;
    asm("mov sp,%0; ":"=r" (sp));
    return sp;
}

#ifndef CONFIG_KGDB
void arch_release_thread_info(struct thread_info *ti);
#endif
#define get_thread_info(ti) get_task_struct((ti)->task)
#define put_thread_info(ti) put_task_struct((ti)->task)

#else /* !__ASSEMBLY__ */

#ifndef __VMLINUX_LDS__
/* how to get the thread information struct from ASM */
.macro GET_THREAD_INFO reg
    mov sp,\reg
    and -THREAD_SIZE,\reg
.endm
#endif
#endif

/*
 * 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_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_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)

#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 */

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

#endif /* __KERNEL__ */

#endif /* _ASM_THREAD_INFO_H */