dms.c

nucleus 2006 source code

/*************************************************************************/
/*                                                                       */
/*               Copyright Mentor Graphics Corporation 2004              */
/*                         All Rights Reserved.                          */
/*                                                                       */
/* THIS WORK CONTAINS TRADE SECRET AND PROPRIETARY INFORMATION WHICH IS  */
/* THE PROPERTY OF MENTOR GRAPHICS CORPORATION OR ITS LICENSORS AND IS   */
/* SUBJECT TO LICENSE TERMS.                                             */
/*                                                                       */
/*************************************************************************/

/*************************************************************************/
/*                                                                       */
/* FILE NAME                                               VERSION       */
/*                                                                       */
/*      dms.c                                          Nucleus PLUS 1.15 */
/*                                                                       */
/* COMPONENT                                                             */
/*                                                                       */
/*      DM - Dynamic Memory Management                                   */
/*                                                                       */
/* DESCRIPTION                                                           */
/*                                                                       */
/*      This file contains the supplemental routines for the Dynamic     */
/*      Memory Management component.                                     */
/*                                                                       */
/* DATA STRUCTURES                                                       */
/*                                                                       */
/*      None                                                             */
/*                                                                       */
/* FUNCTIONS                                                             */
/*                                                                       */
/*      DMS_Allocate_Aligned_Memory         Allocate an aligned memory   */
/*                                            block from  a dynamic      */
/*                                            memory pool                */
/* DEPENDENCIES                                                          */
/*                                                                       */
/*      cs_extr.h                           Common Service functions     */
/*      tc_extr.h                           Thread Control functions     */
/*      dm_extr.h                           Partition functions          */
/*      hi_extr.h                           History functions            */
/*                                                                       */
/*************************************************************************/
#define         NU_SOURCE_FILE

#include        "plus/inc/cs_extr.h"        /* Common service functions  */
#include        "plus/inc/tc_extr.h"        /* Thread control functions  */
#include        "plus/inc/dm_extr.h"        /* Dynamic memory functions  */
#include        "plus/inc/hi_extr.h"        /* History functions         */


/* Define external inner-component global data references.  */


/* Define internal component function prototypes.  */
VOID    DMC_Cleanup(VOID *information);


/*************************************************************************/
/*                                                                       */
/* FUNCTION                                                              */
/*                                                                       */
/*      DMS_Allocate_Aligned_Memory                                      */
/*                                                                       */
/* DESCRIPTION                                                           */
/*                                                                       */
/*      This function allocates memory from the specified dynamic memory */
/*      pool.  If dynamic memory is currently available, this function   */
/*      is completed immediately.  Otherwise, if there is not enough     */
/*      memory currently available, task suspension is possible.         */
/*                                                                       */
/* CALLED BY                                                             */
/*                                                                       */
/*      Application                                                      */
/*                                                                       */
/* CALLS                                                                 */
/*                                                                       */
/*      CSC_Place_On_List                   Place on suspend list        */
/*      [HIC_Make_History_Entry]            Make entry in history log    */
/*      TCC_Suspend_Task                    Suspend calling task         */
/*      TCC_Task_Priority                   Pickup task priority         */
/*      [TCT_Check_Stack]                   Stack checking function      */
/*      TCT_Current_Thread                  Pickup current thread pointer*/
/*      TCT_Protect                         Protect memory pool          */
/*      TCT_Set_Suspend_Protect             Save suspend protection      */
/*      TCT_System_Protect                  Protect system structures    */
/*      TCT_Unprotect                       Release protection           */
/*      TCT_Unprotect_Specific              Release specific protection  */
/*                                                                       */
/* INPUTS                                                                */
/*                                                                       */
/*      pool_ptr                            Memory pool pointer          */
/*      return_pointer                      Pointer to the destination   */
/*                                            memory pointer             */
/*      size                                Number of bytes requested    */
/*      alignment                           Required alignment of        */
/*                                            destination memory pointer */
/*      suspend                             Suspension option if full    */
/*                                                                       */
/* OUTPUTS                                                               */
/*                                                                       */
/*      NU_SUCCESS                          If service is successful     */
/*      NU_NO_MEMORY                        Memory not available         */
/*      NU_TIMEOUT                          If timeout on service        */
/*      NU_POOL_DELETED                     If memory pool deleted       */
/*                                            during suspension          */
/*                                                                       */
/*************************************************************************/
STATUS  DMS_Allocate_Aligned_Memory(NU_MEMORY_POOL *pool_ptr,
                                    VOID **return_pointer, UNSIGNED size,
                                    UNSIGNED alignment, UNSIGNED suspend)
{
R1 DM_PCB      *pool;                       /* Pool control block ptr    */
R2 DM_SUSPEND  *suspend_ptr;                /* Pointer to suspend block  */
DM_SUSPEND      suspend_block;              /* Allocate suspension block */
R4 DM_HEADER   *memory_ptr;                 /* Pointer to memory         */
R3 DM_HEADER   *new_ptr;                    /* New split block pointer   */
UNSIGNED        free_size;                  /* Size of block found       */
TC_TCB         *task;                       /* Task pointer              */
STATUS          status;                     /* Completion status         */
UNSIGNED        address;                    /* Address of start of block */
UNSIGNED        split_size;                 /* Bytes for front split     */
UNSIGNED        next_aligned;               /* Next aligned block addr   */
NU_SUPERV_USER_VARIABLES

    /* Switch to supervisor mode */
    NU_SUPERVISOR_MODE();

    /* Move input pool pointer into internal pointer.  */
    pool =  (DM_PCB *) pool_ptr;


#ifdef  NU_ENABLE_STACK_CHECK

    /* Call stack checking function to check for an overflow condition.  */
    TCT_Check_Stack();

#endif

#ifdef  NU_ENABLE_HISTORY

    /* Make an entry that corresponds to this function in the system history
       log.  */
    HIC_Make_History_Entry(NU_ALLOCATE_ALIGNED_ID, (UNSIGNED) pool,
                        (UNSIGNED) return_pointer, (UNSIGNED) size);

#endif

    /* Initialize the status as successful.  */
    status =  NU_SUCCESS;

    /* Adjust the request to a size evenly divisible by the number of bytes
       in an UNSIGNED data element.  Also, check to make sure it is of the
       minimum size.  */
    if (size < pool -> dm_min_allocation)

        /* Change size to the minimum allocation.  */
        size =  pool -> dm_min_allocation;
    else

        /* Insure that size is a multiple of the UNSIGNED size.  */
        size =
           ((size + sizeof(UNSIGNED) - 1)/sizeof(UNSIGNED)) * sizeof(UNSIGNED);

    /* Adjust the requested alignment to one evenly divisible by the number of
       bytes in an UNSIGNED data element. */
    alignment =
        ((alignment + sizeof(UNSIGNED) - 1)/sizeof(UNSIGNED)) * sizeof(UNSIGNED);

    /* Protect against simultaneous access to the memory pool.  */
    TCT_Protect(&(pool -> dm_protect));

    /* Search the memory list for the first available block of memory that
       satisfies the request.  Note that blocks are merged during the
       deallocation function.  */
    memory_ptr =  pool -> dm_search_ptr;
    do
    {

        /* Determine if the block is free and if it can satisfy the request. */
        if (memory_ptr -> dm_memory_free)

            /* Calculate the free block size.  */
            free_size =  (((BYTE_PTR) (memory_ptr -> dm_next_memory)) -
                           ((BYTE_PTR) memory_ptr)) - DM_OVERHEAD;
        else

            /* There are no free bytes available.  */
            free_size =  0;

        /* Free block may be large enough, now check alignment */
        if (free_size >= size)
        {
            address = ((UNSIGNED)(memory_ptr)) + DM_OVERHEAD;

            /* Is this free block, minus the overhead, already aligned? */
            if (address % alignment != 0)
            {
                /* Not aligned, can the free block be split in front? */
                next_aligned = address + (alignment - 1);
                next_aligned /= alignment;
                next_aligned *= alignment;
                split_size = next_aligned - address;

                /* Is space from start of block to aligned location large enough
                   to contain 2 DM_OVERHEAD plus pool -> dm_min_allocation? */
                if (split_size < ((2 * DM_OVERHEAD) + pool -> dm_min_allocation))
                {
                    /* No, so try to make space for overhead and dm_min_allocation */
                    next_aligned = address + (2 * DM_OVERHEAD) +
                                  (pool -> dm_min_allocation) + (alignment - 1);
                    next_aligned /= alignment;
                    next_aligned *= alignment;