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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. #include <types.h>
  40.  
  41. /**
  42.  * Either 4*256M on 32-bit architecures or 16*256M on 64-bit architectures.
  43.  */
  44. #define MAX_HEAP_SIZE   (sizeof(uintptr_t)<<28)
  45.  
  46. /** Create address space area.
  47.  *
  48.  * @param address Virtual address where to place new address space area.
  49.  * @param size Size of the area.
  50.  * @param flags Flags describing type of the area.
  51.  *
  52.  * @return address on success, (void *) -1 otherwise.
  53.  */
  54. void *as_area_create(void *address, size_t size, int flags)
  55. {
  56.     return (void *) __SYSCALL3(SYS_AS_AREA_CREATE, (sysarg_t ) address, (sysarg_t) size, (sysarg_t) flags);
  57. }
  58.  
  59. /** Resize address space area.
  60.  *
  61.  * @param address Virtual address pointing into already existing address space area.
  62.  * @param size New requested size of the area.
  63.  * @param flags Currently unused.
  64.  *
  65.  * @return Zero on success or a code from @ref errno.h on failure.
  66.  */
  67. int as_area_resize(void *address, size_t size, int flags)
  68. {
  69.     return __SYSCALL3(SYS_AS_AREA_RESIZE, (sysarg_t ) address, (sysarg_t) size, (sysarg_t) flags);
  70. }
  71.  
  72. /** Destroy address space area.
  73.  *
  74.  * @param address Virtual address pointing into the address space area being destroyed.
  75.  *
  76.  * @return Zero on success or a code from @ref errno.h on failure.
  77.  */
  78. int as_area_destroy(void *address)
  79. {
  80.     return __SYSCALL1(SYS_AS_AREA_DESTROY, (sysarg_t ) address);
  81. }
  82.  
  83. static size_t heapsize = 0;
  84. static size_t maxheapsize = (size_t) (-1);
  85.  
  86. static void * last_allocated = 0;
  87.  
  88. /* Start of heap linker symbol */
  89. extern char _heap;
  90.  
  91. /** Sbrk emulation
  92.  *
  93.  * @param incr New area that should be allocated or negative,
  94.                if it should be shrinked
  95.  * @return Pointer to newly allocated area
  96.  */
  97. void *sbrk(ssize_t incr)
  98. {
  99.     int rc;
  100.     void *res;
  101.    
  102.     /* Check for invalid values */
  103.     if (incr < 0 && -incr > heapsize)
  104.         return NULL;
  105.    
  106.     /* Check for too large value */
  107.     if (incr > 0 && incr+heapsize < heapsize)
  108.         return NULL;
  109.    
  110.     /* Check for too small values */
  111.     if (incr < 0 && incr+heapsize > heapsize)
  112.         return NULL;
  113.    
  114.     /* Check for user limit */
  115.     if ((maxheapsize != (size_t) (-1)) && (heapsize + incr) > maxheapsize)
  116.         return NULL;
  117.    
  118.     rc = as_area_resize(&_heap, heapsize + incr, 0);
  119.     if (rc != 0)
  120.         return NULL;
  121.    
  122.     /* Compute start of new area */
  123.     res = (void *) &_heap + heapsize;
  124.  
  125.     heapsize += incr;
  126.  
  127.     return res;
  128. }
  129.  
  130. /** Set maximum heap size and return pointer just after the heap */
  131. void *set_maxheapsize(size_t mhs)
  132. {
  133.     maxheapsize = mhs;
  134.     /* Return pointer to area not managed by sbrk */
  135.     return ((void *) &_heap + maxheapsize);
  136.  
  137. }
  138.  
  139. /** Return pointer to some unmapped area, where fits new as_area
  140.  *
  141.  * TODO: make some first_fit/... algorithm, we are now just incrementing
  142.  *       the pointer to last area
  143.  */
  144. void * as_get_mappable_page(size_t sz)
  145. {
  146.     void *res;
  147.  
  148.     /* Set heapsize to some meaningful value */
  149.     if (maxheapsize == -1)
  150.         set_maxheapsize(MAX_HEAP_SIZE);
  151.    
  152.     if (!last_allocated)
  153.         last_allocated = (void *) ALIGN_UP((void *) &_heap + maxheapsize, PAGE_SIZE);
  154.    
  155.     sz = ALIGN_UP(sz, PAGE_SIZE);
  156.     res = last_allocated;
  157.     last_allocated += sz;
  158.  
  159.     return res;
  160. }
  161.  
  162. /** @}
  163.  */
  164.