libgloss/or1k/impure.c

   1 /* impure.c. Handling of re-entrancy data structure for OpenRISC 1000.
   2
   3    Copyright (C) 2014, Authors
   4
   5    Contributor Stefan Wallentowitz <stefan.wallentowitz@tum.de>
   6
   7  * The authors hereby grant permission to use, copy, modify, distribute,
   8  * and license this software and its documentation for any purpose, provided
   9  * that existing copyright notices are retained in all copies and that this
  10  * notice is included verbatim in any distributions. No written agreement,
  11  * license, or royalty fee is required for any of the authorized uses.
  12  * Modifications to this software may be copyrighted by their authors
  13  * and need not follow the licensing terms described here, provided that
  14  * the new terms are clearly indicated on the first page of each file where
  15  * they apply.
  16  */
  17
  18 #include <reent.h>
  19 #include "or1k-internals.h"
  20
  21 #include <string.h>
  22
  23 /* As an exception handler may also use the library, it is better to use
  24  * a different re-entrancy data structure for the exceptions.
  25  * This data structure is configured here and as part of the exception
  26  * handler (or1k_exception_handler) temporarily replaces the software's
  27  * impure data pointer.
  28  *
  29  * During initialization, the libraries standard _impure_data and the exception
  30  * impure data (_exception_impure_data) are initialized. Afterwards,
  31  * the current value _current_impure_ptr is set to _impure_ptr.
  32  *
  33  * At runtime __getreent is called to return the current reentrancy pointer,
  34  * which is stored in _current_impure_ptr.
  35  *
  36  * In the or1k_exception_handler the _current_impure_ptr is set to point to
  37  * _exception_impure_ptr. After the exception handler returned, it is set back
  38  * to _impure_ptr.
  39  */
  40
  41 /* Link in the external impure_data structure */
  42 extern struct _reent *__ATTRIBUTE_IMPURE_PTR__ _impure_ptr;
  43
  44 #ifdef __OR1K_MULTICORE__
  45 struct _reent **_or1k_impure_ptr;
  46 struct _reent **_or1k_exception_impure_ptr;
  47 struct _reent **_or1k_current_impure_ptr;
  48 #else
  49 struct _reent *__ATTRIBUTE_IMPURE_PTR__ _or1k_impure_ptr;
  50
  51 /* Create exception impure data structure */
  52 static struct _reent _or1k_exception_impure_data = _REENT_INIT (_or1k_exception_impure_data);
  53
  54 /* Link to the exception impure data structure */
  55 struct _reent *__ATTRIBUTE_IMPURE_PTR__ _or1k_exception_impure_ptr = &_or1k_exception_impure_data;
  56
  57 /* Link to the currently used data structure. */
  58 struct _reent *__ATTRIBUTE_IMPURE_PTR__ _or1k_current_impure_ptr;
  59 #endif
  60
  61 #ifdef __OR1K_MULTICORE__
  62 #define OR1K_LIBC_GETREENT _or1k_current_impure_ptr[or1k_coreid()]
  63 #else
  64 #define OR1K_LIBC_GETREENT _or1k_current_impure_ptr
  65 #endif
  66
  67 void
  68 _or1k_libc_impure_init (void)
  69 {
  70 #ifdef __OR1K_MULTICORE__
  71         uint32_t c;
  72
  73         _or1k_impure_ptr = _sbrk_r(0, sizeof(struct _reent*) * or1k_numcores());
  74         _or1k_exception_impure_ptr = _sbrk_r(0, sizeof(struct _reent*) * or1k_numcores());
  75         _or1k_current_impure_ptr = _sbrk_r(0, sizeof(struct _reent*) * or1k_numcores());
  76
  77         _or1k_impure_ptr[0] = _impure_ptr;
  78         _REENT_INIT_PTR(_impure_ptr);
  79         for (c = 1; c < or1k_numcores(); c++) {
  80                 _or1k_impure_ptr[c] = _sbrk_r(0, sizeof(struct _reent));
  81                 _REENT_INIT_PTR(_or1k_impure_ptr[c]);
  82         }
  83
  84         for (c = 0; c < or1k_numcores(); c++) {
  85                 _or1k_exception_impure_ptr[c] = _sbrk_r(0, sizeof(struct _reent));
  86                 _REENT_INIT_PTR(_or1k_exception_impure_ptr[c]);
  87         }
  88
  89         for (c = 0; c < or1k_numcores(); c++) {
  90                 _or1k_current_impure_ptr[c] = _or1k_impure_ptr[c];
  91         }
  92 #else
  93         // Initialize both impure data structures
  94         _REENT_INIT_PTR (_impure_ptr);
  95         _REENT_INIT_PTR (_or1k_exception_impure_ptr);
  96
  97         // Use the standard impure ptr during normal software run
  98         _or1k_impure_ptr = _impure_ptr;
  99
 100         // Set current to standard impure pointer
 101         _or1k_current_impure_ptr = _impure_ptr;
 102 #endif
 103 }
 104
 105 struct _reent*
 106 _or1k_libc_getreent(void) {
 107         return OR1K_LIBC_GETREENT;
 108 }
 109
 110 #ifdef __OR1K_MULTICORE__
 111 struct _or1k_reent (*_or1k_reent)[];
 112 #else
 113 struct _or1k_reent _or1k_reent;
 114 #endif
 115
 116 void
 117 _or1k_reent_init(void)
 118 {
 119 #ifdef __OR1K_MULTICORE__
 120         size_t memsize = sizeof(struct _or1k_reent) * or1k_numcores();
 121         _or1k_reent = (struct _or1k_reent*) _sbrk_r(0, memsize);
 122 #endif
 123 }