[c932d85] | 1 | /* |
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| 2 | * rtems-ctor.cc |
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| 3 | * |
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| 4 | * Description: |
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| 5 | * This file exists solely to (try to) ensure RTEMS is initialized |
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| 6 | * before any global constructors are run. |
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| 7 | * |
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| 8 | * The problem: |
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| 9 | * Global constructors might reasonably expect that new() will |
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| 10 | * work, but since new() uses malloc() which uses RTEMS regions, |
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| 11 | * it can not be called until after initialize_executive(). |
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| 12 | * |
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| 13 | * Global constructors are called in GNU systems one of 2 ways: |
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| 14 | * |
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| 15 | * an "invisible" call to __main() inserted by compiler |
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| 16 | * This __main() calls __do_global_ctors() which |
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| 17 | * walks thru the table and calls all global |
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| 18 | * constructors. |
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| 19 | * |
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| 20 | * or - |
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| 21 | * A special section is put into the linked binary. The |
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| 22 | * system startup code knows to run the constructors in |
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| 23 | * this special section before calling main(). |
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| 24 | * |
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| 25 | * By making RTEMS initialization a constructor, we avoid having |
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| 26 | * too much about all this. All we have to guarantee is that |
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| 27 | * this constructor is the first one run. |
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| 28 | * |
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| 29 | * |
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| 30 | * So for the first case above, this is what happens |
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| 31 | * |
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| 32 | * host crt0 |
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| 33 | * main() |
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| 34 | * __main() |
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| 35 | * __do_global_ctors() |
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| 36 | * bsp_start() |
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| 37 | * init_executive_early() |
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| 38 | * <<any other constructors>> |
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| 39 | * |
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| 40 | * rtems_init_executive_late() |
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| 41 | * bsp_cleanup() |
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| 42 | * |
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| 43 | * TODO: |
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| 44 | * |
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| 45 | * COPYRIGHT (c) 1989-1998. |
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| 46 | * On-Line Applications Research Corporation (OAR). |
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| 47 | * Copyright assigned to U.S. Government, 1994. |
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| 48 | * |
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| 49 | * The license and distribution terms for this file may in |
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| 50 | * the file LICENSE in this distribution or at |
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| 51 | * http://www.OARcorp.com/rtems/license.html. |
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| 52 | * |
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| 53 | * $Id$ |
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| 54 | */ |
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| 55 | |
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| 56 | #include <bsp.h> |
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| 57 | |
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| 58 | /* |
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| 59 | * RTEMS program name |
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| 60 | * Probably not used by anyone, but it is nice to have it. |
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| 61 | * Actually the UNIX version of CPU_INVOKE_DEBUGGER will probably |
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| 62 | * need to use it |
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| 63 | */ |
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| 64 | |
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| 65 | char *rtems_progname; |
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| 66 | char **rtems_environp; |
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| 67 | |
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| 68 | #ifdef USE_CONSTRUCTORS_FOR_INIT_EXEC |
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| 69 | |
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| 70 | class RTEMS { |
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| 71 | public: |
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| 72 | RTEMS(); |
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| 73 | ~RTEMS(); |
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| 74 | }; |
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| 75 | |
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| 76 | RTEMS rtems_constructor; |
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| 77 | |
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| 78 | |
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| 79 | /* PAGE |
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| 80 | * |
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| 81 | * RTEMS::RTEMS |
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| 82 | * |
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| 83 | * RTEMS constructor routine |
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| 84 | * |
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| 85 | * Input parameters: NONE |
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| 86 | * |
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| 87 | * Output parameters: NONE |
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| 88 | * |
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| 89 | * Return values: NONE |
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| 90 | */ |
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| 91 | |
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| 92 | RTEMS::RTEMS() |
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| 93 | { |
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| 94 | bsp_start(); |
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| 95 | } |
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| 96 | |
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| 97 | /* PAGE |
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| 98 | * |
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| 99 | * RTEMS::~RTEMS |
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| 100 | * |
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| 101 | * RTEMS distructor routine |
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| 102 | * |
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| 103 | * Input parameters: NONE |
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| 104 | * |
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| 105 | * Output parameters: NONE |
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| 106 | * |
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| 107 | * Return values: NONE |
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| 108 | */ |
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| 109 | |
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| 110 | RTEMS::~RTEMS() |
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| 111 | { |
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| 112 | bsp_cleanup(); |
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| 113 | } |
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| 114 | #endif |
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| 115 | |
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| 116 | extern "C" { |
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| 117 | int |
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| 118 | main(int argc, |
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| 119 | char **argv, |
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| 120 | char **environp) |
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| 121 | { |
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| 122 | |
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| 123 | #ifndef USE_CONSTRUCTORS_FOR_INIT_EXEC |
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| 124 | bsp_start(); |
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| 125 | #endif |
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| 126 | |
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| 127 | if ((argc > 0) && argv && argv[0]) |
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| 128 | rtems_progname = argv[0]; |
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| 129 | else |
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| 130 | rtems_progname = "RTEMS"; |
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| 131 | |
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| 132 | rtems_environp = environp; |
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| 133 | |
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| 134 | /* |
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| 135 | * Start multitasking |
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| 136 | */ |
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| 137 | |
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| 138 | rtems_initialize_executive_late( bsp_isr_level ); |
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| 139 | |
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| 140 | #ifndef USE_CONSTRUCTORS_FOR_INIT_EXEC |
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| 141 | bsp_cleanup(); |
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| 142 | #endif |
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| 143 | |
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| 144 | /* |
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| 145 | * Returns when multitasking is stopped |
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| 146 | * This allows our destructors to get run normally |
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| 147 | */ |
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| 148 | |
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| 149 | return 0; |
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| 150 | } |
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| 151 | } |
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