thread_info.h

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#ifndef _ALPHA_THREAD_INFO_H
#define _ALPHA_THREAD_INFO_H

#ifdef __KERNEL__

#ifndef __ASSEMBLY__
#include <asm/processor.h>
#include <asm/types.h>
#include <asm/hwrpb.h>
#include <asm/sysinfo.h>
#endif

#ifndef __ASSEMBLY__
struct thread_info {
    struct pcb_struct   pcb;        /* palcode state */

    struct task_struct  *task;      /* main task structure */
    unsigned int        flags;      /* low level flags */
    unsigned int        ieee_state; /* see fpu.h */

    struct exec_domain  *exec_domain;   /* execution domain */
    mm_segment_t        addr_limit; /* thread address space */
    unsigned        cpu;        /* current CPU */
    int         preempt_count; /* 0 => preemptable, <0 => BUG */
    unsigned int        status;     /* thread-synchronous flags */

    int bpt_nsaved;
    unsigned long bpt_addr[2];      /* breakpoint handling  */
    unsigned int bpt_insn[2];

    struct restart_block    restart_block;
};

/*
 * Macros/functions for gaining access to the thread information structure.
 */
#define INIT_THREAD_INFO(tsk)           \
{                       \
    .task       = &tsk,         \
    .exec_domain    = &default_exec_domain, \
    .addr_limit = KERNEL_DS,        \
    .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)

/* How to get the thread information struct from C.  */
register struct thread_info *__current_thread_info __asm__("$8");
#define current_thread_info()  __current_thread_info

#endif /* __ASSEMBLY__ */

/* Thread information allocation.  */
#define THREAD_SIZE_ORDER 1
#define THREAD_SIZE (2*PAGE_SIZE)

#define PREEMPT_ACTIVE      0x40000000

/*
 * Thread information flags:
 * - these are process state flags and used from assembly
 * - pending work-to-be-done flags come first and must be assigned to be
 *   within bits 0 to 7 to fit in and immediate operand.
 *
 * TIF_SYSCALL_TRACE is known to be 0 via blbs.
 */
#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_DIE_IF_KERNEL   9   /* dik recursion lock */
#define TIF_MEMDIE      13  /* is terminating due to OOM killer */

#define _TIF_SYSCALL_TRACE  (1<<TIF_SYSCALL_TRACE)
#define _TIF_SIGPENDING     (1<<TIF_SIGPENDING)
#define _TIF_NEED_RESCHED   (1<<TIF_NEED_RESCHED)
#define _TIF_NOTIFY_RESUME  (1<<TIF_NOTIFY_RESUME)

/* Work to do on interrupt/exception return.  */
#define _TIF_WORK_MASK      (_TIF_SIGPENDING | _TIF_NEED_RESCHED | \
                 _TIF_NOTIFY_RESUME)

/* Work to do on any return to userspace.  */
#define _TIF_ALLWORK_MASK   (_TIF_WORK_MASK     \
                 | _TIF_SYSCALL_TRACE)

#define TS_UAC_NOPRINT      0x0001  /* ! Preserve the following three */
#define TS_UAC_NOFIX        0x0002  /* ! flags as they match          */
#define TS_UAC_SIGBUS       0x0004  /* ! userspace part of 'osf_sysinfo' */
#define TS_RESTORE_SIGMASK  0x0008  /* restore signal mask in do_signal() */
#define TS_POLLING      0x0010  /* idle task polling need_resched,
                       skip sending interrupt */

#define tsk_is_polling(t) (task_thread_info(t)->status & TS_POLLING)

#ifndef __ASSEMBLY__
#define HAVE_SET_RESTORE_SIGMASK    1
static inline void set_restore_sigmask(void)
{
    struct thread_info *ti = current_thread_info();
    ti->status |= TS_RESTORE_SIGMASK;
    WARN_ON(!test_bit(TIF_SIGPENDING, (unsigned long *)&ti->flags));
}
static inline void clear_restore_sigmask(void)
{
    current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
}
static inline bool test_restore_sigmask(void)
{
    return current_thread_info()->status & TS_RESTORE_SIGMASK;
}
static inline bool test_and_clear_restore_sigmask(void)
{
    struct thread_info *ti = current_thread_info();
    if (!(ti->status & TS_RESTORE_SIGMASK))
        return false;
    ti->status &= ~TS_RESTORE_SIGMASK;
    return true;
}
#endif

#define SET_UNALIGN_CTL(task,value) ({              \
    __u32 status = task_thread_info(task)->status & ~UAC_BITMASK;   \
    if (value & PR_UNALIGN_NOPRINT)                 \
        status |= TS_UAC_NOPRINT;               \
    if (value & PR_UNALIGN_SIGBUS)                  \
        status |= TS_UAC_SIGBUS;                \
    if (value & 4)  /* alpha-specific */                \
        status |= TS_UAC_NOFIX;                 \
    task_thread_info(task)->status = status;            \
    0; })

#define GET_UNALIGN_CTL(task,value) ({              \
    __u32 status = task_thread_info(task)->status & ~UAC_BITMASK;   \
    __u32 res = 0;                          \
    if (status & TS_UAC_NOPRINT)                    \
        res |= PR_UNALIGN_NOPRINT;              \
    if (status & TS_UAC_SIGBUS)                 \
        res |= PR_UNALIGN_SIGBUS;               \
    if (status & TS_UAC_NOFIX)                  \
        res |= 4;                       \
    put_user(res, (int __user *)(value));               \
    })

#endif /* __KERNEL__ */
#endif /* _ALPHA_THREAD_INFO_H */