walnux/arch/arm/src/armv7-a/arm_addrenv.c

/****************************************************************************
 * arch/arm/src/armv7/arm_addrenv.c
 *
 *   Copyright (C) 2014 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/
/****************************************************************************
 * Address Environment Interfaces
 *
 * Low-level interfaces used in binfmt/ to instantiate tasks with address
 * environments.  These interfaces all operate on type group_addrenv_t which
 * is an abstract representation of a task group's address environment and
 * must be defined in arch/arch.h if CONFIG_ARCH_ADDRENV is defined.
 *
 *   up_addrenv_create  - Create an address environment
 *   up_addrenv_destroy - Destroy an address environment.
 *   up_addrenv_vtext   - Returns the virtual base address of the .text
 *                        address environment
 *   up_addrenv_vdata   - Returns the virtual base address of the .bss/.data
 *                        address environment
 *   up_addrenv_select  - Instantiate an address environment
 *   up_addrenv_restore - Restore an address environment
 *   up_addrenv_assign  - Assign an address environment to a group
 *
 * Higher-level interfaces used by the tasking logic.  These interfaces are
 * used by the functions in sched/ and all operate on the thread which whose
 * group been assigned an address environment by up_addrenv_assign().
 *
 *   up_addrenv_attach  - Clone the address environment assigned to one TCB
 *                        to another.  This operation is done when a pthread
 *                        is created that share's the same address
 *                        environment.
 *   up_addrenv_detach  - Release the threads reference to an address
 *                        environment when a task/thread exits.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <string.h>
#include <errno.h>

#include <nuttx/arch.h>
#include <nuttx/addrenv.h>
#include <arch/arch.h>

#ifdef CONFIG_ARCH_ADDRENV

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/
/* Configuration ************************************************************/

/****************************************************************************
 * Private Data
 ****************************************************************************/

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: up_addrenv_create
 *
 * Description:
 *   This function is called when a new task is created in order to
 *   instantiate an address environment for the new task group.
 *   up_addrenv_create() is essentially the allocator of the physical
 *   memory for the new task.
 *
 * Input Parameters:
 *   textsize - The size (in bytes) of the .text address environment needed
 *     by the task.  This region may be read/execute only.
 *   datasize - The size (in bytes) of the .data/.bss address environment
 *     needed by the task.  This region may be read/write only.
 *   addrenv - The location to return the representation of the task address
 *     environment.
 *
 * Returned Value:
 *   Zero (OK) on success; a negated errno value on failure.
 *
 ****************************************************************************/

int up_addrenv_create(size_t textsize, size_t datasize,
                      FAR group_addrenv_t *addrenv)
{
#warning Missing logic
  return -ENOSYS;
}

/****************************************************************************
 * Name: up_addrenv_destroy
 *
 * Description:
 *   This function is called when a final thread leaves the task group and
 *   the task group is destroyed.  This function then destroys the defunct
 *   address environment, releasing the underlying physical memory.
 *
 * Input Parameters:
 *   addrenv - The address environment to be destroyed.
 *
 * Returned Value:
 *   Zero (OK) on success; a negated errno value on failure.
 *
 ****************************************************************************/

int up_addrenv_destroy(group_addrenv_t addrenv)
{
#warning Missing logic
  return -ENOSYS;
}

/****************************************************************************
 * Name: up_addrenv_vtext
 *
 * Description:
 *   Return the virtual address associated with the newly create .text
 *   address environment.  This function is used by the binary loaders in
 *   order get an address that can be used to initialize the new task.
 *
 * Input Parameters:
 *   addrenv - The representation of the task address environment previously
 *      returned by up_addrenv_create.
 *   vtext - The location to return the virtual address.
 *
 * Returned Value:
 *   Zero (OK) on success; a negated errno value on failure.
 *
 ****************************************************************************/

int up_addrenv_vtext(FAR group_addrenv_t addrenv, FAR void **vtext)
{
  /* Not much to do in this case */

  DEBUGASSERT(addrenv && vtext);
  *vtext = (FAR void *)CONFIG_ARCH_TEXT_VBASE;
  return OK;
}

/****************************************************************************
 * Name: up_addrenv_vdata
 *
 * Description:
 *   Return the virtual address associated with the newly create .text
 *   address environment.  This function is used by the binary loaders in
 *   order get an address that can be used to initialize the new task.
 *
 * Input Parameters:
 *   addrenv - The representation of the task address environment previously
 *      returned by up_addrenv_create.
 *   textsize - For some implementations, the text and data will be saved
 *      in the same memory region (read/write/execute) and, in this case,
 *      the virtual address of the data just lies at this offset into the
 *      common region.
 *   vdata - The location to return the virtual address.
 *
 * Returned Value:
 *   Zero (OK) on success; a negated errno value on failure.
 *
 ****************************************************************************/

int up_addrenv_vdata(FAR group_addrenv_t addrenv, uintptr_t textsize,
                     FAR void **vdata)
{
  /* Not much to do in this case */

  DEBUGASSERT(addrenv && vdata);
  *vdata = (FAR void *)CONFIG_ARCH_DATA_VBASE;
  return OK;
}

/****************************************************************************
 * Name: up_addrenv_select
 *
 * Description:
 *   After an address environment has been established for a task group (via
 *   up_addrenv_create().  This function may be called to to instantiate
 *   that address environment in the virtual address space.  this might be
 *   necessary, for example, to load the code for the task group from a file or
 *   to access address environment private data.
 *
 * Input Parameters:
 *   addrenv - The representation of the task address environment previously
 *     returned by up_addrenv_create.
 *   oldenv
 *     The address environment that was in place before up_addrenv_select().
 *     This may be used with up_addrenv_restore() to restore the original
 *     address environment that was in place before up_addrenv_select() was
 *     called.  Note that this may be a task agnostic, platform-specific
 *     representation that may or may not be different from group_addrenv_t.
 *
 * Returned Value:
 *   Zero (OK) on success; a negated errno value on failure.
 *
 ****************************************************************************/

int up_addrenv_select(group_addrenv_t addrenv, save_addrenv_t *oldenv)
{
#warning Missing logic
  return -ENOSYS;
}

/****************************************************************************
 * Name: up_addrenv_restore
 *
 * Description:
 *   After an address environment has been temporarily instantiated by
 *   up_addrenv_select(), this function may be called to to restore the
 *   original address environment.
 *
 * Input Parameters:
 *   oldenv - The platform-specific representation of the address environment
 *     previously returned by up_addrenv_select.
 *
 * Returned Value:
 *   Zero (OK) on success; a negated errno value on failure.
 *
 ****************************************************************************/

int up_addrenv_restore(save_addrenv_t oldenv)
{
#warning Missing logic
  return -ENOSYS;
}

/****************************************************************************
 * Name: up_addrenv_assign
 *
 * Description:
 *   Assign an address environment to a new task group.
 *
 * Input Parameters:
 *   addrenv - The representation of the task address environment previously
 *     returned by up_addrenv_create().
 *   group - The new task group to receive the address environment.
 *
 * Returned Value:
 *   Zero (OK) on success; a negated errno value on failure.
 *
 ****************************************************************************/

int up_addrenv_assign(FAR const group_addrenv_t *addrenv,
                      FAR struct task_group_s *group)
{
  DEBUGASSERT(addrenv && group);

  /* Just copy the addess environment into the group */

  memcpy(&group->addrenv, addrenv, sizeof(group_addrenv_t));
  return OK;
}

/****************************************************************************
 * Name: up_addrenv_attach
 *
 * Description:
 *   This function is called from the core scheduler logic when a thread
 *   is created that needs to share the address environment of its task
 *   group.
 *
 *   NOTE: In some platforms, nothing will need to be done in this case.
 *   Simply being a member of the group that has the address environment
 *   may be sufficient.
 *
 * Input Parameters:
 *   group - The task group to which the new thread belongs.
 *   tcb   - The TCB of the thread needing the address environment.
 *
 * Returned Value:
 *   Zero (OK) on success; a negated errno value on failure.
 *
 ****************************************************************************/

int up_addrenv_attach(FAR struct task_group_s *group, FAR struct tcb_s *tcb)
{
  /* Nothing needs to be done in this implementation */

  return OK;
}

/****************************************************************************
 * Name: up_addrenv_detach
 *
 * Description:
 *   This function is called when a task or thread exits in order to release
 *   its reference to an address environment.  The address environment,
 *   however, should persist until up_addrenv_destroy() is called when the
 *   task group is itself destroyed.  Any resources unique to this thread
 *   may be destroyed now.
 *
 *   NOTE: In some platforms, nothing will need to be done in this case.
 *   Simply being a member of the group that has the address environment
 *   may be sufficient.
 *
 * Input Parameters:
 *   group - The group to which the thread belonged.
 *   tcb - The TCB of the task or thread whose the address environment will
 *     be released.
 *
 * Returned Value:
 *   Zero (OK) on success; a negated errno value on failure.
 *
 ****************************************************************************/

int up_addrenv_detach(FAR struct task_group_s *group, FAR struct tcb_s *tcb)
{
  /* Nothing needs to be done in this implementation */

  return OK;
}

#endif /* CONFIG_ARCH_ADDRENV */