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  1. /*
  2.  * Copyright (C) 2006 Jakub Jermar
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. #include <as.h>
  30. #include <libc.h>
  31. #include <unistd.h>
  32. #include <align.h>
  33.  
  34. /** Create address space area.
  35.  *
  36.  * @param address Virtual address where to place new address space area.
  37.  * @param size Size of the area.
  38.  * @param flags Flags describing type of the area.
  39.  *
  40.  * @return address on success, (void *) -1 otherwise.
  41.  */
  42. void *as_area_create(void *address, size_t size, int flags)
  43. {
  44.     return (void *) __SYSCALL3(SYS_AS_AREA_CREATE, (sysarg_t ) address, (sysarg_t) size, (sysarg_t) flags);
  45. }
  46.  
  47. /** Resize address space area.
  48.  *
  49.  * @param address Virtual address pointing into already existing address space area.
  50.  * @param size New requested size of the area.
  51.  * @param flags Currently unused.
  52.  *
  53.  * @return Zero on success or a code from @ref errno.h on failure.
  54.  */
  55. int as_area_resize(void *address, size_t size, int flags)
  56. {
  57.     return __SYSCALL3(SYS_AS_AREA_RESIZE, (sysarg_t ) address, (sysarg_t) size, (sysarg_t) flags);
  58. }
  59.  
  60. /** Destroy address space area.
  61.  *
  62.  * @param address Virtual address pointing into the address space area being destroyed.
  63.  *
  64.  * @return Zero on success or a code from @ref errno.h on failure.
  65.  */
  66. int as_area_destroy(void *address)
  67. {
  68.     return __SYSCALL1(SYS_AS_AREA_DESTROY, (sysarg_t ) address);
  69. }
  70.  
  71. static size_t heapsize = 0;
  72. static size_t maxheapsize = (size_t)(-1);
  73.  
  74. static void * last_allocated = 0;
  75.  
  76. /* Start of heap linker symbol */
  77. extern char _heap;
  78.  
  79. /** Sbrk emulation
  80.  *
  81.  * @param size New area that should be allocated or negative,
  82.                if it should be shrinked
  83.  * @return Pointer to newly allocated area
  84.  */
  85. void *sbrk(ssize_t incr)
  86. {
  87.     int rc;
  88.     void *res;
  89.     /* Check for invalid values */
  90.     if (incr < 0 && -incr > heapsize)
  91.         return NULL;
  92.     /* Check for too large value */
  93.     if (incr > 0 && incr+heapsize < heapsize)
  94.         return NULL;
  95.     /* Check for too small values */
  96.     if (incr < 0 && incr+heapsize > heapsize)
  97.         return NULL;
  98.     /* Check for user limit */
  99.     if ((maxheapsize!=(size_t)(-1)) && (heapsize + incr)>maxheapsize) return NULL;
  100.  
  101.     rc = as_area_resize(&_heap, heapsize + incr,0);
  102.     if (rc != 0)
  103.         return NULL;
  104.    
  105.     /* Compute start of new area */
  106.     res = (void *)&_heap + heapsize;
  107.  
  108.     heapsize += incr;
  109.  
  110.     return res;
  111. }
  112.  
  113. /** Set maximum heap size and return pointer just after the heap */
  114. void *set_maxheapsize(size_t mhs)
  115. {
  116.     maxheapsize=mhs;
  117.     /* Return pointer to area not managed by sbrk */
  118.     return (void *)&_heap + maxheapsize;
  119.  
  120. }
  121.  
  122. /** Return pointer to some unmapped area, where fits new as_area
  123.  *
  124.  * TODO: make some first_fit/... algorithm, we are now just incrementing
  125.  *       the pointer to last area
  126.  */
  127. void * as_get_mappable_page(size_t sz)
  128. {
  129.     void *res;
  130.  
  131.     /* Set heapsize to some meaningful value */
  132.     if (maxheapsize == -1)
  133.         set_maxheapsize(ALIGN_UP(USER_ADDRESS_SPACE_SIZE_ARCH>>1,PAGE_SIZE));
  134.     if (!last_allocated)
  135.         last_allocated = ALIGN_UP((void *)&_heap + maxheapsize, PAGE_SIZE);
  136.    
  137.     sz = ALIGN_UP(sz, PAGE_SIZE);
  138.     res = last_allocated;
  139.     last_allocated += sz;
  140.  
  141.     return res;
  142. }
  143.