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/*

 * Initialise posix-related structures.

 *

 * Copyright (C) 2007-2009 Bahadir Balban

 */

#include <l4lib/kip.h>

#include <l4lib/ipcdefs.h>

#include <l4/macros.h>

#include <stdio.h>

#include <shpage.h>

#include <sys/types.h>

#include <sys/shm.h>

#include <shpage.h>

#include <libposix.h>

#include INC_GLUE(memlayout.h)

#if 0

/*

 * Shared page initialisation of posix-like tasks.

 *

 * POSIX tasks currently use a default shared page for communciation.

 * This could have been also done by long ipc calls.

 */

/*

 * Shared page for this task. Used for passing data among ipc

 * parties when message registers are not big enough. Every thread

 * has right to own one, and it has an address unique to every

 * thread. It must be explicitly mapped by both parties of the ipc

 * in order to be useful.

 */

void *shared_page;

/*

 * Obtains a unique address for the task's shared page. Note this

 * just returns the address. This address is used as an shm key

 * to map it via shmget()/shmat() later on.

 */

static void *shared_page_address(void)

{

        void *addr;

        int err;

        /* We're asking it for ourself. */

        write_mr(L4SYS_ARG0, self_tid());

        /* Call pager with utcb address request. Check ipc error. */

        if ((err = l4_sendrecv(pagerid, pagerid,

                               L4_IPC_TAG_SHPAGE)) < 0) {

                print_err("%s: L4 IPC Error: %d.\n", __FUNCTION__, err);

                return PTR_ERR(err);

        }

        /* Check if syscall itself was successful */

        if (IS_ERR(addr = (void *)l4_get_retval())) {

                print_err("%s: Request UTCB Address Error: %d.\n",

                       __FUNCTION__, (int)addr);

                return addr;

        }

        return addr;

}

/*

 * Initialises a non-pager task's default shared memory page

 * using posix semantics. Used during task initialisation

 * and by child tasks after a fork.

 */

int shared_page_init(void)

{

        int shmid;

        void *shmaddr;

        /*

         * Initialise shared page only if we're not the pager.

         * The pager does it differently for itself.

         */

        BUG_ON(self_tid() == pagerid);

        /* Obtain our shared page address */

        shared_page = shared_page_address();

        //print_err("%s: UTCB Read from mm0 as: 0x%x\n", __FUNCTION__,

        //       (unsigned long)shared_page);

        /* Use it as a key to create a shared memory region */

        BUG_ON((shmid = shmget((key_t)shared_page,

                               PAGE_SIZE, IPC_CREAT)) < 0);

        /* Attach to the region */

        BUG_ON((shmaddr = shmat(shmid, shared_page, 0)) < 0);

        BUG_ON(shmaddr != shared_page);

        return 0;

}

#endif