text: /****************************************************************************
   * arch/risc-v/src/common/riscv_addrenv_kstack.c
   *
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.  The
   * ASF licenses this file to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance with the
   * License.  You may obtain a copy of the License at
   *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
   * License for the specific language governing permissions and limitations
   * under the License.
   *
   ****************************************************************************/
  
  /****************************************************************************
   * Included Files
   ****************************************************************************/
  
  #include <nuttx/config.h>
  
  #include <errno.h>
  #include <assert.h>
  #include <debug.h>
  
  #include <nuttx/sched.h>
  #include <nuttx/kmalloc.h>
  #include <nuttx/addrenv.h>
  #include <nuttx/arch.h>
  
  #include "addrenv.h"
  #include "riscv_internal.h"
  
  #if defined(CONFIG_ARCH_ADDRENV) && defined(CONFIG_ARCH_KERNEL_STACK)
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: up_addrenv_kstackalloc
   *
   * Description:
   *   This function is called when a new thread is created to allocate
   *   the new thread's kernel stack.   This function may be called for certain
   *   terminating threads which have no kernel stack.  It must be tolerant of
   *   that case.
   *
   * Input Parameters:
   *   tcb - The TCB of the thread that requires the kernel stack.
   *
   * Returned Value:
   *   Zero (OK) on success; a negated errno value on failure.
   *
   ****************************************************************************/
  
  int up_addrenv_kstackalloc(struct tcb_s *tcb)
  {
    DEBUGASSERT(tcb && tcb->xcp.kstack == NULL);
  
    /* Allocate the kernel stack */
  
    tcb->xcp.kstack = (uintptr_t *)kmm_memalign(STACK_ALIGNMENT,
                                                ARCH_KERNEL_STACKSIZE);
    if (!tcb->xcp.kstack)
      {
        berr("ERROR: Failed to allocate the kernel stack\n");
        return -ENOMEM;
      }
  
    return OK;
  }
  
  /****************************************************************************
   * Name: up_addrenv_kstackfree
   *
   * Description:
   *   This function is called when any thread exits.  This function frees
   *   the kernel stack.
   *
   * Input Parameters:
   *   tcb - The TCB of the thread that no longer requires the kernel stack.
   *
   * Returned Value:
   *   Zero (OK) on success; a negated errno value on failure.
   *
   ****************************************************************************/
  
  int up_addrenv_kstackfree(struct tcb_s *tcb)
  {
    DEBUGASSERT(tcb);
  
    /* Does the exiting thread have a kernel stack? */
  
    if (tcb->xcp.kstack)
      {
        /* Yes.. Free the kernel stack */
  
        kmm_free(tcb->xcp.kstack);
        tcb->xcp.kstack = NULL;
      }
  
    return OK;
  }
  
  #endif /* CONFIG_ARCH_ADDRENV && CONFIG_ARCH_KERNEL_STACK */
  