text: /****************************************************************************
   * arch/csky/src/common/up_createstack.c
   *
   *   Copyright (C) 2011, 2013, 2015 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.
   *
   ****************************************************************************/
  
  /****************************************************************************
   * Included Files
   ****************************************************************************/
  
  #include <nuttx/config.h>
  
  #include <sys/types.h>
  #include <stdint.h>
  #include <sched.h>
  #include <debug.h>
  
  #include <nuttx/kmalloc.h>
  #include <nuttx/arch.h>
  #include <nuttx/board.h>
  #include <arch/board/board.h>
  
  #include "up_arch.h"
  #include "up_internal.h"
  
  /****************************************************************************
   * Pre-processor Macros
   ****************************************************************************/
  
  /* CSKY requires at least a 4-byte stack alignment.  For use with ABIV1
   * floating point, the stack must be aligned to 8-byte addresses.
   */
  
  #ifndef CONFIG_STACK_ALIGNMENT
  
  /* The symbol  __CSKYABIV1__ is defined by GCC if EABI is being used.  If you
   * are not using GCC, make sure that CONFIG_STACK_ALIGNMENT is set correctly!
   */
  
  #ifdef __CSKYABIV1__
  #    define CONFIG_STACK_ALIGNMENT 8
  #else
  #    define CONFIG_STACK_ALIGNMENT 4
  #endif
  #endif
  
  /* Stack alignment macros */
  
  #define STACK_ALIGN_MASK    (CONFIG_STACK_ALIGNMENT-1)
  #define STACK_ALIGN_DOWN(a) ((a) & ~STACK_ALIGN_MASK)
  #define STACK_ALIGN_UP(a)   (((a) + STACK_ALIGN_MASK) & ~STACK_ALIGN_MASK)
  
  /****************************************************************************
   * Private Types
   ****************************************************************************/
  
  /****************************************************************************
   * Private Function Prototypes
   ****************************************************************************/
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: up_create_stack
   *
   * Description:
   *   Allocate a stack for a new thread and setup up stack-related information
   *   in the TCB.
   *
   *   The following TCB fields must be initialized by this function:
   *
   *   - adj_stack_size: Stack size after adjustment for hardware, processor,
   *     etc.  This value is retained only for debug purposes.
   *   - stack_alloc_ptr: Pointer to allocated stack
   *   - adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The initial value of
   *     the stack pointer.
   *
   * Input Parameters:
   *   - tcb: The TCB of new task
   *   - stack_size:  The requested stack size.  At least this much
   *     must be allocated.
   *   - ttype:  The thread type.  This may be one of following (defined in
   *     include/nuttx/sched.h):
   *
   *       TCB_FLAG_TTYPE_TASK     Normal user task
   *       TCB_FLAG_TTYPE_PTHREAD  User pthread
   *       TCB_FLAG_TTYPE_KERNEL   Kernel thread
   *
   *     This thread type is normally available in the flags field of the TCB,
   *     however, there are certain contexts where the TCB may not be fully
   *     initialized when up_create_stack is called.
   *
   *     If CONFIG_BUILD_KERNEL is defined, then this thread type may affect
   *     how the stack is allocated.  For example, kernel thread stacks should
   *     be allocated from protected kernel memory.  Stacks for user tasks and
   *     threads must come from memory that is accessible to user code.
   *
   ****************************************************************************/
  
  int up_create_stack(FAR struct tcb_s *tcb, size_t stack_size, uint8_t ttype)
  {
    /* Is there already a stack allocated of a different size?  Because of
     * alignment issues, stack_size might erroneously appear to be of a
     * different size.  Fortunately, this is not a critical operation.
     */
  
    if (tcb->stack_alloc_ptr && tcb->adj_stack_size != stack_size)
      {
        /* Yes.. Release the old stack */
  
        up_release_stack(tcb, ttype);
      }
  
    /* Do we need to allocate a new stack? */
  
    if (!tcb->stack_alloc_ptr)
      {
        /* Allocate the stack.  If DEBUG is enabled (but not stack debug),
         * then create a zeroed stack to make stack dumps easier to trace.
         */
  
  #if defined(CONFIG_BUILD_KERNEL) && defined(CONFIG_MM_KERNEL_HEAP)
        /* Use the kernel allocator if this is a kernel thread */
  
        if (ttype == TCB_FLAG_TTYPE_KERNEL)
          {
            tcb->stack_alloc_ptr = (uint32_t *)kmm_malloc(stack_size);
          }
        else
  #endif
          {
            /* Use the user-space allocator if this is a task or pthread */
  
            tcb->stack_alloc_ptr = (uint32_t *)kumm_malloc(stack_size);
          }
  
  #ifdef CONFIG_DEBUG_FEATURES
        /* Was the allocation successful? */
  
        if (!tcb->stack_alloc_ptr)
          {
            serr("ERROR: Failed to allocate stack, size %d\n", stack_size);
          }
  #endif
      }
  
    /* Did we successfully allocate a stack? */
  
    if (tcb->stack_alloc_ptr)
      {
        size_t top_of_stack;
        size_t size_of_stack;
  
        /* Yes.. If stack debug is enabled, then fill the stack with a
         * recognizable value that we can use later to test for high
         * water marks.
         */
  
  #ifdef CONFIG_STACK_COLORATION
        up_stack_color(tcb->stack_alloc_ptr, stack_size);
  #endif
  
        /* CSKY uses a push-down stack:  the stack grows toward lower
         * addresses in memory.  The stack pointer register points to the
         * lowest, valid working address (the "top" of the stack).  Items on
         * the stack are referenced as positive word offsets from sp.
         */
  
        top_of_stack = (uint32_t)tcb->stack_alloc_ptr + stack_size - 4;
  
        /* The CSKY stack must be aligned at word (4 byte) boundaries; for
         * floating point use, the stack must be aligned to 8-byte addresses.
         * If necessary top_of_stack must be rounded down to the next
         * boundary to meet these alignment requirements.
         */
  
        top_of_stack = STACK_ALIGN_DOWN(top_of_stack);
        size_of_stack = top_of_stack - (uint32_t)tcb->stack_alloc_ptr + 4;
  
        /* Save the adjusted stack values in the struct tcb_s */
  
        tcb->adj_stack_ptr  = (FAR uint32_t *)top_of_stack;
        tcb->adj_stack_size = size_of_stack;
  
        board_autoled_on(LED_STACKCREATED);
        return OK;
      }
  
     return ERROR;
  }
  
  /****************************************************************************
   * Name: up_stack_color
   *
   * Description:
   *   Write a well know value into the stack
   *
   ****************************************************************************/
  
  #ifdef CONFIG_STACK_COLORATION
  void up_stack_color(FAR void *stackbase, size_t nbytes)
  {
    /* Take extra care that we do not write outsize the stack boundaries */
  
    uint32_t *stkptr = (uint32_t *)(((uintptr_t)stackbase + 3) & ~3);
    uintptr_t stkend = (((uintptr_t)stackbase + nbytes) & ~3);
    size_t    nwords = (stkend - (uintptr_t)stackbase) >> 2;
  
    /* Set the entire stack to the coloration value */
  
    while (nwords-- > 0)
      {
        *stkptr++ = STACK_COLOR;
      }
  }
  #endif
  