root/include/asm-xtensa/thread_info.h

INCLUDED FROM

DEFINITIONS

1. current_thread_info

/*
 * 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
 *
 * preempt_count needs to be 1 initially, until the scheduler is functional.
 */

#ifndef __ASSEMBLY__

#define INIT_THREAD_INFO(tsk)                   \
{                                               \
        .task           = &tsk,                 \
        .exec_domain    = &default_exec_domain, \
        .flags          = 0,                    \
        .cpu            = 0,                    \
        .preempt_count  = 1,                    \
        .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_IRET                4       /* return with iret */
#define TIF_MEMDIE              5
#define TIF_RESTORE_SIGMASK     6       /* restore signal mask in do_signal() */
#define TIF_POLLING_NRFLAG      16      /* true if poll_idle() is polling TIF_NEED_RESCHED */

#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_IRET               (1<<TIF_IRET)
#define _TIF_POLLING_NRFLAG     (1<<TIF_POLLING_NRFLAG)
#define _TIF_RESTORE_SIGMASK    (1<<TIF_RESTORE_SIGMASK)

#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 */