thread_info.h

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/*
 * include/asm-xtensa/thread_info.h
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2001 - 2005 Tensilica Inc.
 */

#ifndef _XTENSA_THREAD_INFO_H
#define _XTENSA_THREAD_INFO_H

#ifdef __KERNEL__

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

/*
 * 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__

#if XTENSA_HAVE_COPROCESSORS

typedef struct xtregs_coprocessor {
    xtregs_cp0_t cp0;
    xtregs_cp1_t cp1;
    xtregs_cp2_t cp2;
    xtregs_cp3_t cp3;
    xtregs_cp4_t cp4;
    xtregs_cp5_t cp5;
    xtregs_cp6_t cp6;
    xtregs_cp7_t cp7;
} xtregs_coprocessor_t;

#endif

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           cpu;        /* current CPU */
    __s32           preempt_count;  /* 0 => preemptable,< 0 => BUG*/

    mm_segment_t        addr_limit; /* thread address space */
    struct restart_block    restart_block;

    unsigned long       cpenable;

    /* Allocate storage for extra user states and coprocessor states. */
#if XTENSA_HAVE_COPROCESSORS
    xtregs_coprocessor_t    xtregs_cp;
#endif
    xtregs_user_t       xtregs_user;
};

#else /* !__ASSEMBLY__ */

/* offsets into the thread_info struct for assembly code access */
#define TI_TASK      0x00000000
#define TI_EXEC_DOMAIN   0x00000004
#define TI_FLAGS     0x00000008
#define TI_STATUS    0x0000000C
#define TI_CPU       0x00000010
#define TI_PRE_COUNT     0x00000014
#define TI_ADDR_LIMIT    0x00000018
#define TI_RESTART_BLOCK 0x000001C

#endif

#define PREEMPT_ACTIVE      0x10000000

/*
 * 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)

/* how to get the thread information struct from C */
static inline struct thread_info *current_thread_info(void)
{
    struct thread_info *ti;
     __asm__("extui %0,a1,0,13\n\t"
             "xor %0, a1, %0" : "=&r" (ti) : );
    return ti;
}

#else /* !__ASSEMBLY__ */

/* how to get the thread information struct from ASM */
#define GET_THREAD_INFO(reg,sp) \
    extui reg, sp, 0, 13; \
    xor   reg, sp, reg
#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_SIGPENDING      1   /* signal pending */
#define TIF_NEED_RESCHED    2   /* rescheduling necessary */
#define TIF_SINGLESTEP      3   /* restore singlestep on return to user mode */
#define TIF_MEMDIE      5   /* is terminating due to OOM killer */
#define TIF_RESTORE_SIGMASK 6   /* restore signal mask in do_signal() */
#define TIF_NOTIFY_RESUME   7   /* callback before returning to user */

#define _TIF_SYSCALL_TRACE  (1<<TIF_SYSCALL_TRACE)
#define _TIF_SIGPENDING     (1<<TIF_SIGPENDING)
#define _TIF_NEED_RESCHED   (1<<TIF_NEED_RESCHED)
#define _TIF_SINGLESTEP     (1<<TIF_SINGLESTEP)

#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 */

/*
 * 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.
 */
#define TS_USEDFPU      0x0001  /* FPU was used by this task this quantum (SMP) */

#define THREAD_SIZE 8192    //(2*PAGE_SIZE)
#define THREAD_SIZE_ORDER 1

#endif  /* __KERNEL__ */
#endif  /* _XTENSA_THREAD_INFO */