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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. /** @addtogroup libc
  30.  * @{
  31.  */
  32. /** @file
  33.  */
  34.  
  35. #include <as.h>
  36. #include <libc.h>
  37. #include <unistd.h>
  38. #include <align.h>
  39.  
  40. /** Create address space area.
  41.  *
  42.  * @param address Virtual address where to place new address space area.
  43.  * @param size Size of the area.
  44.  * @param flags Flags describing type of the area.
  45.  *
  46.  * @return address on success, (void *) -1 otherwise.
  47.  */
  48. void *as_area_create(void *address, size_t size, int flags)
  49. {
  50.     return (void *) __SYSCALL3(SYS_AS_AREA_CREATE, (sysarg_t ) address, (sysarg_t) size, (sysarg_t) flags);
  51. }
  52.  
  53. /** Resize address space area.
  54.  *
  55.  * @param address Virtual address pointing into already existing address space area.
  56.  * @param size New requested size of the area.
  57.  * @param flags Currently unused.
  58.  *
  59.  * @return Zero on success or a code from @ref errno.h on failure.
  60.  */
  61. int as_area_resize(void *address, size_t size, int flags)
  62. {
  63.     return __SYSCALL3(SYS_AS_AREA_RESIZE, (sysarg_t ) address, (sysarg_t) size, (sysarg_t) flags);
  64. }
  65.  
  66. /** Destroy address space area.
  67.  *
  68.  * @param address Virtual address pointing into the address space area being destroyed.
  69.  *
  70.  * @return Zero on success or a code from @ref errno.h on failure.
  71.  */
  72. int as_area_destroy(void *address)
  73. {
  74.     return __SYSCALL1(SYS_AS_AREA_DESTROY, (sysarg_t ) address);
  75. }
  76.  
  77. static size_t heapsize = 0;
  78. static size_t maxheapsize = (size_t) (-1);
  79.  
  80. static void * last_allocated = 0;
  81.  
  82. /* Start of heap linker symbol */
  83. extern char _heap;
  84.  
  85. /** Sbrk emulation
  86.  *
  87.  * @param incr New area that should be allocated or negative,
  88.                if it should be shrinked
  89.  * @return Pointer to newly allocated area
  90.  */
  91. void *sbrk(ssize_t incr)
  92. {
  93.     int rc;
  94.     void *res;
  95.    
  96.     /* Check for invalid values */
  97.     if (incr < 0 && -incr > heapsize)
  98.         return NULL;
  99.    
  100.     /* Check for too large value */
  101.     if (incr > 0 && incr+heapsize < heapsize)
  102.         return NULL;
  103.    
  104.     /* Check for too small values */
  105.     if (incr < 0 && incr+heapsize > heapsize)
  106.         return NULL;
  107.    
  108.     /* Check for user limit */
  109.     if ((maxheapsize != (size_t) (-1)) && (heapsize + incr) > maxheapsize)
  110.         return NULL;
  111.    
  112.     rc = as_area_resize(&_heap, heapsize + incr, 0);
  113.     if (rc != 0)
  114.         return NULL;
  115.    
  116.     /* Compute start of new area */
  117.     res = (void *) &_heap + heapsize;
  118.  
  119.     heapsize += incr;
  120.  
  121.     return res;
  122. }
  123.  
  124. /** Set maximum heap size and return pointer just after the heap */
  125. void *set_maxheapsize(size_t mhs)
  126. {
  127.     maxheapsize = mhs;
  128.     /* Return pointer to area not managed by sbrk */
  129.     return ((void *) &_heap + maxheapsize);
  130.  
  131. }
  132.  
  133. /** Return pointer to some unmapped area, where fits new as_area
  134.  *
  135.  * TODO: make some first_fit/... algorithm, we are now just incrementing
  136.  *       the pointer to last area
  137.  */
  138. void * as_get_mappable_page(size_t sz)
  139. {
  140.     void *res;
  141.  
  142.     /* Set heapsize to some meaningful value */
  143.     if (maxheapsize == -1)
  144.         set_maxheapsize(ALIGN_UP(USER_ADDRESS_SPACE_SIZE_ARCH >> 1, PAGE_SIZE));
  145.    
  146.     if (!last_allocated)
  147.         last_allocated = (void *) ALIGN_UP((void *) &_heap + maxheapsize, PAGE_SIZE);
  148.    
  149.     sz = ALIGN_UP(sz, PAGE_SIZE);
  150.     res = last_allocated;
  151.     last_allocated += sz;
  152.  
  153.     return res;
  154. }
  155.  
  156. /** @}
  157.  */
  158.