1 | /* SPDX-License-Identifier: BSD-2-Clause */ |
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2 | |
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3 | /** |
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4 | * @file |
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5 | * |
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6 | * @ingroup POSIXAPI |
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7 | * |
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8 | * @brief System Generates Signal for process after realtime seconds elapsed |
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9 | */ |
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10 | |
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11 | /* |
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12 | * 3.4.1 Schedule Alarm, P1003.1b-1993, p. 79 |
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13 | */ |
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14 | |
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15 | /* COPYRIGHT (c) 1989-2013. |
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16 | * On-Line Applications Research Corporation (OAR). |
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17 | * |
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18 | * Redistribution and use in source and binary forms, with or without |
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19 | * modification, are permitted provided that the following conditions |
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20 | * are met: |
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21 | * 1. Redistributions of source code must retain the above copyright |
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22 | * notice, this list of conditions and the following disclaimer. |
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23 | * 2. Redistributions in binary form must reproduce the above copyright |
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24 | * notice, this list of conditions and the following disclaimer in the |
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25 | * documentation and/or other materials provided with the distribution. |
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26 | * |
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27 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
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28 | * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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29 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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30 | * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
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31 | * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
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32 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
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33 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
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34 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
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35 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
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36 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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37 | * POSSIBILITY OF SUCH DAMAGE. |
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38 | */ |
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39 | |
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40 | #ifdef HAVE_CONFIG_H |
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41 | #include "config.h" |
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42 | #endif |
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43 | |
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44 | #include <unistd.h> |
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45 | #include <signal.h> |
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46 | |
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47 | #include <rtems/score/todimpl.h> |
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48 | #include <rtems/score/watchdogimpl.h> |
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49 | |
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50 | ISR_LOCK_DEFINE( static, _POSIX_signals_Alarm_lock, "POSIX Alarm" ) |
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51 | |
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52 | static void _POSIX_signals_Alarm_TSR( Watchdog_Control *the_watchdog ) |
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53 | { |
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54 | int status; |
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55 | |
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56 | status = kill( getpid(), SIGALRM ); |
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57 | |
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58 | #if defined(RTEMS_DEBUG) |
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59 | /* |
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60 | * There is no reason to think this might fail but we should be |
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61 | * cautious. |
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62 | */ |
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63 | _Assert(status == 0); |
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64 | #else |
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65 | (void) status; |
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66 | #endif |
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67 | } |
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68 | |
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69 | static Watchdog_Control _POSIX_signals_Alarm_watchdog = WATCHDOG_INITIALIZER( |
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70 | _POSIX_signals_Alarm_TSR |
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71 | ); |
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72 | |
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73 | unsigned int alarm( |
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74 | unsigned int seconds |
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75 | ) |
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76 | { |
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77 | unsigned int remaining; |
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78 | Watchdog_Control *the_watchdog; |
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79 | ISR_lock_Context lock_context; |
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80 | ISR_lock_Context lock_context2; |
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81 | Per_CPU_Control *cpu; |
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82 | uint64_t now; |
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83 | uint32_t ticks_per_second; |
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84 | uint32_t ticks; |
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85 | |
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86 | the_watchdog = &_POSIX_signals_Alarm_watchdog; |
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87 | ticks_per_second = TOD_TICKS_PER_SECOND; |
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88 | ticks = seconds * ticks_per_second; |
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89 | |
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90 | _ISR_lock_ISR_disable_and_acquire( |
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91 | &_POSIX_signals_Alarm_lock, |
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92 | &lock_context |
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93 | ); |
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94 | |
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95 | cpu = _Watchdog_Get_CPU( the_watchdog ); |
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96 | _Watchdog_Per_CPU_acquire_critical( cpu, &lock_context2 ); |
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97 | now = cpu->Watchdog.ticks; |
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98 | |
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99 | remaining = (unsigned long) _Watchdog_Cancel( |
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100 | &cpu->Watchdog.Header[ PER_CPU_WATCHDOG_TICKS ], |
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101 | the_watchdog, |
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102 | now |
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103 | ); |
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104 | |
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105 | if ( ticks != 0 ) { |
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106 | _Watchdog_Insert( |
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107 | &cpu->Watchdog.Header[ PER_CPU_WATCHDOG_TICKS ], |
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108 | the_watchdog, |
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109 | now + ticks |
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110 | ); |
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111 | } |
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112 | |
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113 | _Watchdog_Per_CPU_release_critical( cpu, &lock_context2 ); |
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114 | _ISR_lock_Release_and_ISR_enable( |
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115 | &_POSIX_signals_Alarm_lock, |
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116 | &lock_context |
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117 | ); |
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118 | |
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119 | return ( remaining + ticks_per_second - 1 ) / ticks_per_second; |
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120 | } |
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