thread_info.h

Go to the documentation of this file.

/*
 * Copyright (C) 2002  David Howells ([email protected])
 * Copyright 2010 Tilera Corporation. All Rights Reserved.
 *
 *   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, version 2.
 *
 *   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, GOOD TITLE or
 *   NON INFRINGEMENT.  See the GNU General Public License for
 *   more details.
 */

#ifndef _ASM_TILE_THREAD_INFO_H
#define _ASM_TILE_THREAD_INFO_H

#include <asm/processor.h>
#include <asm/page.h>
#ifndef __ASSEMBLY__

/*
 * Low level task data that assembly code needs immediate access to.
 * The structure is placed at the bottom of the supervisor stack.
 */
struct thread_info {
    struct task_struct  *task;      /* main task structure */
    struct exec_domain  *exec_domain;   /* execution domain */
    unsigned long       flags;      /* low level flags */
    unsigned long       status;     /* thread-synchronous flags */
    __u32           homecache_cpu;  /* CPU we are homecached on */
    __u32           cpu;        /* current CPU */
    int         preempt_count;  /* 0 => preemptable,
                           <0 => BUG */

    mm_segment_t        addr_limit; /* thread address space
                           (KERNEL_DS or USER_DS) */
    struct restart_block    restart_block;
    struct single_step_state *step_state;   /* single step state
                           (if non-zero) */
};

/*
 * 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,   \
    .addr_limit = KERNEL_DS,        \
    .restart_block  = {         \
        .fn = do_no_restart_syscall,    \
    },                  \
    .step_state = NULL,         \
}

#define init_thread_info    (init_thread_union.thread_info)
#define init_stack      (init_thread_union.stack)

#endif /* !__ASSEMBLY__ */

#if PAGE_SIZE < 8192
#define THREAD_SIZE_ORDER (13 - PAGE_SHIFT)
#else
#define THREAD_SIZE_ORDER (0)
#endif
#define THREAD_SIZE_PAGES (1 << THREAD_SIZE_ORDER)

#define THREAD_SIZE (PAGE_SIZE << THREAD_SIZE_ORDER)
#define LOG2_THREAD_SIZE (PAGE_SHIFT + THREAD_SIZE_ORDER)

#define STACK_WARN             (THREAD_SIZE/8)

#ifndef __ASSEMBLY__

void arch_release_thread_info(struct thread_info *info);

/* How to get the thread information struct from C. */
register unsigned long stack_pointer __asm__("sp");

#define current_thread_info() \
  ((struct thread_info *)(stack_pointer & -THREAD_SIZE))

/* Sit on a nap instruction until interrupted. */
extern void smp_nap(void);

/* Enable interrupts racelessly and nap forever: helper for cpu_idle(). */
extern void _cpu_idle(void);

#else /* __ASSEMBLY__ */

/*
 * How to get the thread information struct from assembly.
 * Note that we use different macros since different architectures
 * have different semantics in their "mm" instruction and we would
 * like to guarantee that the macro expands to exactly one instruction.
 */
#ifdef __tilegx__
#define EXTRACT_THREAD_INFO(reg) mm reg, zero, LOG2_THREAD_SIZE, 63
#else
#define GET_THREAD_INFO(reg) mm reg, sp, zero, LOG2_THREAD_SIZE, 31
#endif

#endif /* !__ASSEMBLY__ */

#define PREEMPT_ACTIVE      0x10000000

/*
 * Thread information flags that various assembly files may need to access.
 * Keep flags accessed frequently in low bits, particular since it makes
 * it easier to build constants in assembly.
 */
#define TIF_SIGPENDING      0   /* signal pending */
#define TIF_NEED_RESCHED    1   /* rescheduling necessary */
#define TIF_SINGLESTEP      2   /* restore singlestep on return to
                       user mode */
#define TIF_ASYNC_TLB       3   /* got an async TLB fault in kernel */
#define TIF_SYSCALL_TRACE   4   /* syscall trace active */
#define TIF_SYSCALL_AUDIT   5   /* syscall auditing active */
#define TIF_SECCOMP     6   /* secure computing */
#define TIF_MEMDIE      7   /* OOM killer at work */
#define TIF_NOTIFY_RESUME   8   /* callback before returning to user */

#define _TIF_SIGPENDING     (1<<TIF_SIGPENDING)
#define _TIF_NEED_RESCHED   (1<<TIF_NEED_RESCHED)
#define _TIF_SINGLESTEP     (1<<TIF_SINGLESTEP)
#define _TIF_ASYNC_TLB      (1<<TIF_ASYNC_TLB)
#define _TIF_SYSCALL_TRACE  (1<<TIF_SYSCALL_TRACE)
#define _TIF_SYSCALL_AUDIT  (1<<TIF_SYSCALL_AUDIT)
#define _TIF_SECCOMP        (1<<TIF_SECCOMP)
#define _TIF_MEMDIE     (1<<TIF_MEMDIE)
#define _TIF_NOTIFY_RESUME  (1<<TIF_NOTIFY_RESUME)

/* Work to do on any return to user space. */
#define _TIF_ALLWORK_MASK \
  (_TIF_SIGPENDING|_TIF_NEED_RESCHED|_TIF_SINGLESTEP|\
   _TIF_ASYNC_TLB|_TIF_NOTIFY_RESUME)

/*
 * Thread-synchronous status.
 *
 * This is different from the flags in that nobody else
 * ever touches our thread-synchronous status, so we don't
 * have to worry about atomic accesses.
 */
#ifdef __tilegx__
#define TS_COMPAT       0x0001  /* 32-bit compatibility mode */
#endif
#define TS_POLLING      0x0004  /* in idle loop but not sleeping */
#define TS_RESTORE_SIGMASK  0x0008  /* restore signal mask in do_signal */

#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, &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  /* !__ASSEMBLY__ */

#endif /* _ASM_TILE_THREAD_INFO_H */