[c81ebf9] | 1 | // |
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| 2 | // Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo |
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| 3 | // |
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| 4 | // The contents of this file are covered under the licence agreement in the |
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| 5 | // file "LICENCE" distributed with Cforall. |
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| 6 | // |
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| 7 | // signal.c -- |
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| 8 | // |
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| 9 | // Author : Thierry Delisle |
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| 10 | // Created On : Mon Jun 5 14:20:42 2017 |
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[6b0b624] | 11 | // Last Modified By : Peter A. Buhr |
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[c1ee231] | 12 | // Last Modified On : Wed Jun 17 11:36:25 2020 |
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| 13 | // Update Count : 46 |
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[c81ebf9] | 14 | // |
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| 15 | |
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[2026bb6] | 16 | #define __cforall_thread__ |
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| 17 | |
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[73abe95] | 18 | #include "preemption.hfa" |
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[a83ffa4] | 19 | #include <assert.h> |
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[c81ebf9] | 20 | |
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[82ff5845] | 21 | #include <errno.h> |
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| 22 | #include <stdio.h> |
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| 23 | #include <string.h> |
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| 24 | #include <unistd.h> |
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[27f5f71] | 25 | #include <limits.h> // PTHREAD_STACK_MIN |
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[c81ebf9] | 26 | |
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[73abe95] | 27 | #include "bits/signal.hfa" |
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[82ff5845] | 28 | |
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[d8548e2] | 29 | #if !defined(__CFA_DEFAULT_PREEMPTION__) |
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[2a84d06d] | 30 | #define __CFA_DEFAULT_PREEMPTION__ 10`ms |
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[d8548e2] | 31 | #endif |
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[c81ebf9] | 32 | |
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[2a84d06d] | 33 | Duration default_preemption() __attribute__((weak)) { |
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[c81ebf9] | 34 | return __CFA_DEFAULT_PREEMPTION__; |
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| 35 | } |
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| 36 | |
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[969b3fe] | 37 | // FwdDeclarations : timeout handlers |
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[c81ebf9] | 38 | static void preempt( processor * this ); |
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[9b1dcc2] | 39 | static void timeout( struct __processor_id_t * id, $thread * this ); |
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[c81ebf9] | 40 | |
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[969b3fe] | 41 | // FwdDeclarations : Signal handlers |
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[c29c342] | 42 | static void sigHandler_ctxSwitch( __CFA_SIGPARMS__ ); |
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[c59a346] | 43 | static void sigHandler_alarm ( __CFA_SIGPARMS__ ); |
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[c29c342] | 44 | static void sigHandler_segv ( __CFA_SIGPARMS__ ); |
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| 45 | static void sigHandler_ill ( __CFA_SIGPARMS__ ); |
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| 46 | static void sigHandler_fpe ( __CFA_SIGPARMS__ ); |
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| 47 | static void sigHandler_abort ( __CFA_SIGPARMS__ ); |
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[82ff5845] | 48 | |
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[969b3fe] | 49 | // FwdDeclarations : alarm thread main |
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[c29c342] | 50 | static void * alarm_loop( __attribute__((unused)) void * args ); |
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[969b3fe] | 51 | |
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| 52 | // Machine specific register name |
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[381fdee] | 53 | #if defined( __i386 ) |
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[b2b44d8] | 54 | #define CFA_REG_IP gregs[REG_EIP] |
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[381fdee] | 55 | #elif defined( __x86_64 ) |
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| 56 | #define CFA_REG_IP gregs[REG_RIP] |
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| 57 | #elif defined( __ARM_ARCH ) |
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[b2b44d8] | 58 | #define CFA_REG_IP arm_pc |
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[381fdee] | 59 | #else |
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| 60 | #error unknown hardware architecture |
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[cd17862] | 61 | #endif |
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| 62 | |
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[969b3fe] | 63 | KERNEL_STORAGE(event_kernel_t, event_kernel); // private storage for event kernel |
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| 64 | event_kernel_t * event_kernel; // kernel public handle to even kernel |
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| 65 | static pthread_t alarm_thread; // pthread handle to alarm thread |
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[09d4b22] | 66 | static void * alarm_stack; // pthread stack for alarm thread |
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[969b3fe] | 67 | |
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[c29c342] | 68 | static void ?{}(event_kernel_t & this) with( this ) { |
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[65deb18] | 69 | alarms{}; |
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| 70 | lock{}; |
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[969b3fe] | 71 | } |
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[82ff5845] | 72 | |
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[4dad189] | 73 | enum { |
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| 74 | PREEMPT_NORMAL = 0, |
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| 75 | PREEMPT_TERMINATE = 1, |
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| 76 | }; |
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| 77 | |
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[c81ebf9] | 78 | //============================================================================================= |
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| 79 | // Kernel Preemption logic |
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| 80 | //============================================================================================= |
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| 81 | |
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[969b3fe] | 82 | // Get next expired node |
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[2a84d06d] | 83 | static inline alarm_node_t * get_expired( alarm_list_t * alarms, Time currtime ) { |
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[d3ab183] | 84 | if( ! & (*alarms)`first ) return 0p; // If no alarms return null |
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| 85 | if( (*alarms)`first.alarm >= currtime ) return 0p; // If alarms head not expired return null |
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[27f5f71] | 86 | return pop(alarms); // Otherwise just pop head |
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[969b3fe] | 87 | } |
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| 88 | |
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| 89 | // Tick one frame of the Discrete Event Simulation for alarms |
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[9b1dcc2] | 90 | static void tick_preemption( struct __processor_id_t * id ) { |
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[27f5f71] | 91 | alarm_node_t * node = 0p; // Used in the while loop but cannot be declared in the while condition |
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| 92 | alarm_list_t * alarms = &event_kernel->alarms; // Local copy for ease of reading |
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| 93 | Time currtime = __kernel_get_time(); // Check current time once so everything "happens at once" |
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[8cb529e] | 94 | |
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[969b3fe] | 95 | //Loop throught every thing expired |
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| 96 | while( node = get_expired( alarms, currtime ) ) { |
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[b1a4300] | 97 | // __cfaabi_dbg_print_buffer_decl( " KERNEL: preemption tick.\n" ); |
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[185efe6] | 98 | Duration period = node->period; |
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| 99 | if( period == 0) { |
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| 100 | node->set = false; // Node is one-shot, just mark it as not pending |
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| 101 | } |
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[1c273d0] | 102 | |
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[969b3fe] | 103 | // Check if this is a kernel |
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[c81ebf9] | 104 | if( node->kernel_alarm ) { |
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| 105 | preempt( node->proc ); |
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| 106 | } |
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| 107 | else { |
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[9b1dcc2] | 108 | timeout( id, node->thrd ); |
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[c81ebf9] | 109 | } |
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| 110 | |
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[969b3fe] | 111 | // Check if this is a periodic alarm |
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[8cb529e] | 112 | if( period > 0 ) { |
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[b1a4300] | 113 | // __cfaabi_dbg_print_buffer_local( " KERNEL: alarm period is %lu.\n", period.tv ); |
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[969b3fe] | 114 | node->alarm = currtime + period; // Alarm is periodic, add currtime to it (used cached current time) |
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| 115 | insert( alarms, node ); // Reinsert the node for the next time it triggers |
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[c81ebf9] | 116 | } |
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| 117 | } |
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| 118 | |
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[969b3fe] | 119 | // If there are still alarms pending, reset the timer |
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[d3ab183] | 120 | if( & (*alarms)`first ) { |
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[6a490b2] | 121 | __cfadbg_print_buffer_decl(preemption, " KERNEL: @%ju(%ju) resetting alarm to %ju.\n", currtime.tv, __kernel_get_time().tv, (alarms->head->alarm - currtime).tv); |
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[d3ab183] | 122 | Duration delta = (*alarms)`first.alarm - currtime; |
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| 123 | Duration capped = max(delta, 50`us); |
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[b1a4300] | 124 | // itimerval tim = { caped }; |
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| 125 | // __cfaabi_dbg_print_buffer_local( " Values are %lu, %lu, %lu %lu.\n", delta.tv, caped.tv, tim.it_value.tv_sec, tim.it_value.tv_usec); |
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| 126 | |
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[d3ab183] | 127 | __kernel_set_timer( capped ); |
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[b1a4300] | 128 | } |
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[c81ebf9] | 129 | } |
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| 130 | |
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[969b3fe] | 131 | // Update the preemption of a processor and notify interested parties |
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[2a84d06d] | 132 | void update_preemption( processor * this, Duration duration ) { |
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[c81ebf9] | 133 | alarm_node_t * alarm = this->preemption_alarm; |
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| 134 | |
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| 135 | // Alarms need to be enabled |
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[2a84d06d] | 136 | if ( duration > 0 && ! alarm->set ) { |
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[c81ebf9] | 137 | alarm->alarm = __kernel_get_time() + duration; |
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| 138 | alarm->period = duration; |
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| 139 | register_self( alarm ); |
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| 140 | } |
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[8ad6533] | 141 | // Zero duration but alarm is set |
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[c81ebf9] | 142 | else if ( duration == 0 && alarm->set ) { |
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| 143 | unregister_self( alarm ); |
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| 144 | alarm->alarm = 0; |
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| 145 | alarm->period = 0; |
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| 146 | } |
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| 147 | // If alarm is different from previous, change it |
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| 148 | else if ( duration > 0 && alarm->period != duration ) { |
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| 149 | unregister_self( alarm ); |
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| 150 | alarm->alarm = __kernel_get_time() + duration; |
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| 151 | alarm->period = duration; |
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| 152 | register_self( alarm ); |
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| 153 | } |
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| 154 | } |
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| 155 | |
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| 156 | //============================================================================================= |
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[cd17862] | 157 | // Kernel Signal Tools |
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[c81ebf9] | 158 | //============================================================================================= |
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| 159 | |
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[36982fc] | 160 | __cfaabi_dbg_debug_do( static thread_local void * last_interrupt = 0; ) |
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[b227f68] | 161 | |
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[82ff5845] | 162 | extern "C" { |
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[969b3fe] | 163 | // Disable interrupts by incrementing the counter |
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[82ff5845] | 164 | void disable_interrupts() { |
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[afd550c] | 165 | with( kernelTLS.preemption_state ) { |
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[1f81d61] | 166 | #if GCC_VERSION > 50000 |
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[13073be] | 167 | static_assert(__atomic_always_lock_free(sizeof(enabled), &enabled), "Must be lock-free"); |
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[1f81d61] | 168 | #endif |
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[13073be] | 169 | |
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| 170 | // Set enabled flag to false |
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| 171 | // should be atomic to avoid preemption in the middle of the operation. |
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| 172 | // use memory order RELAXED since there is no inter-thread on this variable requirements |
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| 173 | __atomic_store_n(&enabled, false, __ATOMIC_RELAXED); |
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| 174 | |
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| 175 | // Signal the compiler that a fence is needed but only for signal handlers |
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| 176 | __atomic_signal_fence(__ATOMIC_ACQUIRE); |
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| 177 | |
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[de6319f] | 178 | __attribute__((unused)) unsigned short new_val = disable_count + 1; |
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| 179 | disable_count = new_val; |
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| 180 | verify( new_val < 65_000u ); // If this triggers someone is disabling interrupts without enabling them |
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| 181 | } |
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[82ff5845] | 182 | } |
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| 183 | |
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[969b3fe] | 184 | // Enable interrupts by decrementing the counter |
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[c7a900a] | 185 | // If counter reaches 0, execute any pending __cfactx_switch |
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[36982fc] | 186 | void enable_interrupts( __cfaabi_dbg_ctx_param ) { |
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[13073be] | 187 | processor * proc = kernelTLS.this_processor; // Cache the processor now since interrupts can start happening after the atomic store |
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[969b3fe] | 188 | |
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[afd550c] | 189 | with( kernelTLS.preemption_state ){ |
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[de6319f] | 190 | unsigned short prev = disable_count; |
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| 191 | disable_count -= 1; |
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| 192 | verify( prev != 0u ); // If this triggers someone is enabled already enabled interruptsverify( prev != 0u ); |
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| 193 | |
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| 194 | // Check if we need to prempt the thread because an interrupt was missed |
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| 195 | if( prev == 1 ) { |
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[1f81d61] | 196 | #if GCC_VERSION > 50000 |
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[13073be] | 197 | static_assert(__atomic_always_lock_free(sizeof(enabled), &enabled), "Must be lock-free"); |
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[1f81d61] | 198 | #endif |
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[13073be] | 199 | |
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| 200 | // Set enabled flag to true |
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| 201 | // should be atomic to avoid preemption in the middle of the operation. |
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| 202 | // use memory order RELAXED since there is no inter-thread on this variable requirements |
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| 203 | __atomic_store_n(&enabled, true, __ATOMIC_RELAXED); |
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| 204 | |
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| 205 | // Signal the compiler that a fence is needed but only for signal handlers |
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| 206 | __atomic_signal_fence(__ATOMIC_RELEASE); |
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[de6319f] | 207 | if( proc->pending_preemption ) { |
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| 208 | proc->pending_preemption = false; |
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[3381ed7] | 209 | force_yield( __POLL_PREEMPTION ); |
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[de6319f] | 210 | } |
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[d0a045c7] | 211 | } |
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[82ff5845] | 212 | } |
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[4e6fb8e] | 213 | |
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[969b3fe] | 214 | // For debugging purposes : keep track of the last person to enable the interrupts |
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[36982fc] | 215 | __cfaabi_dbg_debug_do( proc->last_enable = caller; ) |
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[82ff5845] | 216 | } |
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[969b3fe] | 217 | |
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| 218 | // Disable interrupts by incrementint the counter |
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[c7a900a] | 219 | // Don't execute any pending __cfactx_switch even if counter reaches 0 |
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[969b3fe] | 220 | void enable_interrupts_noPoll() { |
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[afd550c] | 221 | unsigned short prev = kernelTLS.preemption_state.disable_count; |
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| 222 | kernelTLS.preemption_state.disable_count -= 1; |
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[2e9aed4] | 223 | verifyf( prev != 0u, "Incremented from %u\n", prev ); // If this triggers someone is enabled already enabled interrupts |
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[d0a045c7] | 224 | if( prev == 1 ) { |
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[1f81d61] | 225 | #if GCC_VERSION > 50000 |
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[13073be] | 226 | static_assert(__atomic_always_lock_free(sizeof(kernelTLS.preemption_state.enabled), &kernelTLS.preemption_state.enabled), "Must be lock-free"); |
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[1f81d61] | 227 | #endif |
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[13073be] | 228 | // Set enabled flag to true |
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| 229 | // should be atomic to avoid preemption in the middle of the operation. |
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| 230 | // use memory order RELAXED since there is no inter-thread on this variable requirements |
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| 231 | __atomic_store_n(&kernelTLS.preemption_state.enabled, true, __ATOMIC_RELAXED); |
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| 232 | |
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| 233 | // Signal the compiler that a fence is needed but only for signal handlers |
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| 234 | __atomic_signal_fence(__ATOMIC_RELEASE); |
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[d0a045c7] | 235 | } |
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[969b3fe] | 236 | } |
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[82ff5845] | 237 | } |
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| 238 | |
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[969b3fe] | 239 | // sigprocmask wrapper : unblock a single signal |
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[1c273d0] | 240 | static inline void signal_unblock( int sig ) { |
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[82ff5845] | 241 | sigset_t mask; |
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| 242 | sigemptyset( &mask ); |
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[1c273d0] | 243 | sigaddset( &mask, sig ); |
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[82ff5845] | 244 | |
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[27f5f71] | 245 | if ( pthread_sigmask( SIG_UNBLOCK, &mask, 0p ) == -1 ) { |
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[169d944] | 246 | abort( "internal error, pthread_sigmask" ); |
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[cd17862] | 247 | } |
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[82ff5845] | 248 | } |
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| 249 | |
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[969b3fe] | 250 | // sigprocmask wrapper : block a single signal |
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[cd17862] | 251 | static inline void signal_block( int sig ) { |
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| 252 | sigset_t mask; |
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| 253 | sigemptyset( &mask ); |
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| 254 | sigaddset( &mask, sig ); |
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[47ecf2b] | 255 | |
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[27f5f71] | 256 | if ( pthread_sigmask( SIG_BLOCK, &mask, 0p ) == -1 ) { |
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[c59a346] | 257 | abort( "internal error, pthread_sigmask" ); |
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[cd17862] | 258 | } |
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| 259 | } |
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[47ecf2b] | 260 | |
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[969b3fe] | 261 | // kill wrapper : signal a processor |
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[cd17862] | 262 | static void preempt( processor * this ) { |
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[4dad189] | 263 | sigval_t value = { PREEMPT_NORMAL }; |
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| 264 | pthread_sigqueue( this->kernel_thread, SIGUSR1, value ); |
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| 265 | } |
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| 266 | |
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[969b3fe] | 267 | // reserved for future use |
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[9b1dcc2] | 268 | static void timeout( struct __processor_id_t * id, $thread * this ) { |
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[8834751] | 269 | #if !defined( __CFA_NO_STATISTICS__ ) |
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| 270 | kernelTLS.this_stats = this->curr_cluster->stats; |
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| 271 | #endif |
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[9b1dcc2] | 272 | __unpark( id, this __cfaabi_dbg_ctx2 ); |
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[cd17862] | 273 | } |
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| 274 | |
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[14a61b5] | 275 | // KERNEL ONLY |
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[c7a900a] | 276 | // Check if a __cfactx_switch signal handler shoud defer |
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[969b3fe] | 277 | // If true : preemption is safe |
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| 278 | // If false : preemption is unsafe and marked as pending |
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| 279 | static inline bool preemption_ready() { |
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[14a61b5] | 280 | // Check if preemption is safe |
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| 281 | bool ready = kernelTLS.preemption_state.enabled && ! kernelTLS.preemption_state.in_progress; |
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| 282 | |
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| 283 | // Adjust the pending flag accordingly |
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| 284 | kernelTLS.this_processor->pending_preemption = !ready; |
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[969b3fe] | 285 | return ready; |
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| 286 | } |
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| 287 | |
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[cd17862] | 288 | //============================================================================================= |
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| 289 | // Kernel Signal Startup/Shutdown logic |
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| 290 | //============================================================================================= |
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| 291 | |
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[969b3fe] | 292 | // Startup routine to activate preemption |
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| 293 | // Called from kernel_startup |
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[cd17862] | 294 | void kernel_start_preemption() { |
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[169d944] | 295 | __cfaabi_dbg_print_safe( "Kernel : Starting preemption\n" ); |
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[969b3fe] | 296 | |
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| 297 | // Start with preemption disabled until ready |
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[14a61b5] | 298 | kernelTLS.preemption_state.enabled = false; |
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| 299 | kernelTLS.preemption_state.disable_count = 1; |
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[969b3fe] | 300 | |
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| 301 | // Initialize the event kernel |
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| 302 | event_kernel = (event_kernel_t *)&storage_event_kernel; |
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[9236060] | 303 | (*event_kernel){}; |
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[969b3fe] | 304 | |
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| 305 | // Setup proper signal handlers |
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[c7a900a] | 306 | __cfaabi_sigaction( SIGUSR1, sigHandler_ctxSwitch, SA_SIGINFO | SA_RESTART ); // __cfactx_switch handler |
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[c59a346] | 307 | __cfaabi_sigaction( SIGALRM, sigHandler_alarm , SA_SIGINFO | SA_RESTART ); // debug handler |
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[cd17862] | 308 | |
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| 309 | signal_block( SIGALRM ); |
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| 310 | |
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[8c50aed] | 311 | alarm_stack = __create_pthread( &alarm_thread, alarm_loop, 0p ); |
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[cd17862] | 312 | } |
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| 313 | |
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[969b3fe] | 314 | // Shutdown routine to deactivate preemption |
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| 315 | // Called from kernel_shutdown |
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[cd17862] | 316 | void kernel_stop_preemption() { |
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[169d944] | 317 | __cfaabi_dbg_print_safe( "Kernel : Preemption stopping\n" ); |
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[d6ff3ff] | 318 | |
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[969b3fe] | 319 | // Block all signals since we are already shutting down |
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[cd17862] | 320 | sigset_t mask; |
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| 321 | sigfillset( &mask ); |
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[27f5f71] | 322 | sigprocmask( SIG_BLOCK, &mask, 0p ); |
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[cd17862] | 323 | |
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[969b3fe] | 324 | // Notify the alarm thread of the shutdown |
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[a0b3e32] | 325 | sigval val = { 1 }; |
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| 326 | pthread_sigqueue( alarm_thread, SIGALRM, val ); |
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[969b3fe] | 327 | |
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| 328 | // Wait for the preemption thread to finish |
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[27f5f71] | 329 | |
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| 330 | pthread_join( alarm_thread, 0p ); |
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[09d4b22] | 331 | free( alarm_stack ); |
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[969b3fe] | 332 | |
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| 333 | // Preemption is now fully stopped |
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| 334 | |
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[169d944] | 335 | __cfaabi_dbg_print_safe( "Kernel : Preemption stopped\n" ); |
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[cd17862] | 336 | } |
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| 337 | |
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[969b3fe] | 338 | // Raii ctor/dtor for the preemption_scope |
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| 339 | // Used by thread to control when they want to receive preemption signals |
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[242a902] | 340 | void ?{}( preemption_scope & this, processor * proc ) { |
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[2a84d06d] | 341 | (this.alarm){ proc, (Time){ 0 }, 0`s }; |
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[242a902] | 342 | this.proc = proc; |
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| 343 | this.proc->preemption_alarm = &this.alarm; |
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[969b3fe] | 344 | |
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[d8548e2] | 345 | update_preemption( this.proc, this.proc->cltr->preemption_rate ); |
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[cd17862] | 346 | } |
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| 347 | |
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[242a902] | 348 | void ^?{}( preemption_scope & this ) { |
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[cd17862] | 349 | disable_interrupts(); |
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| 350 | |
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[2a84d06d] | 351 | update_preemption( this.proc, 0`s ); |
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[cd17862] | 352 | } |
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| 353 | |
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| 354 | //============================================================================================= |
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| 355 | // Kernel Signal Handlers |
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| 356 | //============================================================================================= |
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[47ecf2b] | 357 | |
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[969b3fe] | 358 | // Context switch signal handler |
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| 359 | // Receives SIGUSR1 signal and causes the current thread to yield |
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[c29c342] | 360 | static void sigHandler_ctxSwitch( __CFA_SIGPARMS__ ) { |
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[b2b44d8] | 361 | __cfaabi_dbg_debug_do( last_interrupt = (void *)(cxt->uc_mcontext.CFA_REG_IP); ) |
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[969b3fe] | 362 | |
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[4dad189] | 363 | // SKULLDUGGERY: if a thread creates a processor and the immediately deletes it, |
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| 364 | // the interrupt that is supposed to force the kernel thread to preempt might arrive |
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| 365 | // before the kernel thread has even started running. When that happens an iterrupt |
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| 366 | // we a null 'this_processor' will be caught, just ignore it. |
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[14a61b5] | 367 | if(! kernelTLS.this_processor ) return; |
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[4dad189] | 368 | |
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| 369 | choose(sfp->si_value.sival_int) { |
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| 370 | case PREEMPT_NORMAL : ;// Normal case, nothing to do here |
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[ea8b2f7] | 371 | case PREEMPT_TERMINATE: verify( __atomic_load_n( &kernelTLS.this_processor->do_terminate, __ATOMIC_SEQ_CST ) ); |
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[4dad189] | 372 | default: |
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[ff878b7] | 373 | abort( "internal error, signal value is %d", sfp->si_value.sival_int ); |
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[4dad189] | 374 | } |
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| 375 | |
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[b2b44d8] | 376 | // Check if it is safe to preempt here |
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[969b3fe] | 377 | if( !preemption_ready() ) { return; } |
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| 378 | |
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[b1a4300] | 379 | __cfaabi_dbg_print_buffer_decl( " KERNEL: preempting core %p (%p @ %p).\n", kernelTLS.this_processor, kernelTLS.this_thread, (void *)(cxt->uc_mcontext.CFA_REG_IP) ); |
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[14a61b5] | 380 | |
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| 381 | // Sync flag : prevent recursive calls to the signal handler |
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| 382 | kernelTLS.preemption_state.in_progress = true; |
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| 383 | |
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[a83ffa4] | 384 | // Clear sighandler mask before context switching. |
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[1f81d61] | 385 | #if GCC_VERSION > 50000 |
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[a83ffa4] | 386 | static_assert( sizeof( sigset_t ) == sizeof( cxt->uc_sigmask ), "Expected cxt->uc_sigmask to be of sigset_t" ); |
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[1f81d61] | 387 | #endif |
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[27f5f71] | 388 | if ( pthread_sigmask( SIG_SETMASK, (sigset_t *)&(cxt->uc_sigmask), 0p ) == -1 ) { |
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[a83ffa4] | 389 | abort( "internal error, sigprocmask" ); |
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| 390 | } |
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[05615ba] | 391 | |
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[14a61b5] | 392 | // TODO: this should go in finish action |
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| 393 | // Clear the in progress flag |
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| 394 | kernelTLS.preemption_state.in_progress = false; |
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[969b3fe] | 395 | |
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| 396 | // Preemption can occur here |
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| 397 | |
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[c7a900a] | 398 | force_yield( __ALARM_PREEMPTION ); // Do the actual __cfactx_switch |
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[c81ebf9] | 399 | } |
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| 400 | |
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[c59a346] | 401 | static void sigHandler_alarm( __CFA_SIGPARMS__ ) { |
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| 402 | abort("SIGALRM should never reach the signal handler"); |
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[c81ebf9] | 403 | } |
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| 404 | |
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[969b3fe] | 405 | // Main of the alarm thread |
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| 406 | // Waits on SIGALRM and send SIGUSR1 to whom ever needs it |
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[c29c342] | 407 | static void * alarm_loop( __attribute__((unused)) void * args ) { |
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[9b1dcc2] | 408 | __processor_id_t id; |
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| 409 | id.id = doregister(&id); |
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| 410 | |
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[969b3fe] | 411 | // Block sigalrms to control when they arrive |
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[cd17862] | 412 | sigset_t mask; |
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[ade5272] | 413 | sigfillset(&mask); |
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[27f5f71] | 414 | if ( pthread_sigmask( SIG_BLOCK, &mask, 0p ) == -1 ) { |
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[169d944] | 415 | abort( "internal error, pthread_sigmask" ); |
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[82ff5845] | 416 | } |
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[c81ebf9] | 417 | |
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[ade5272] | 418 | sigemptyset( &mask ); |
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| 419 | sigaddset( &mask, SIGALRM ); |
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| 420 | |
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[969b3fe] | 421 | // Main loop |
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[cd17862] | 422 | while( true ) { |
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[969b3fe] | 423 | // Wait for a sigalrm |
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[a0b3e32] | 424 | siginfo_t info; |
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| 425 | int sig = sigwaitinfo( &mask, &info ); |
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[969b3fe] | 426 | |
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[e2f7bc3] | 427 | if( sig < 0 ) { |
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| 428 | //Error! |
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| 429 | int err = errno; |
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| 430 | switch( err ) { |
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| 431 | case EAGAIN : |
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| 432 | case EINTR : |
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[b1a4300] | 433 | {__cfaabi_dbg_print_buffer_decl( " KERNEL: Spurious wakeup %d.\n", err );} |
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[e2f7bc3] | 434 | continue; |
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[27f5f71] | 435 | case EINVAL : |
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[169d944] | 436 | abort( "Timeout was invalid." ); |
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[e2f7bc3] | 437 | default: |
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[169d944] | 438 | abort( "Unhandled error %d", err); |
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[e2f7bc3] | 439 | } |
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| 440 | } |
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| 441 | |
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[969b3fe] | 442 | // If another signal arrived something went wrong |
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[8cb529e] | 443 | assertf(sig == SIGALRM, "Kernel Internal Error, sigwait: Unexpected signal %d (%d : %d)\n", sig, info.si_code, info.si_value.sival_int); |
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| 444 | |
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[169d944] | 445 | // __cfaabi_dbg_print_safe( "Kernel : Caught alarm from %d with %d\n", info.si_code, info.si_value.sival_int ); |
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[969b3fe] | 446 | // Switch on the code (a.k.a. the sender) to |
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[8cb529e] | 447 | switch( info.si_code ) |
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[a0b3e32] | 448 | { |
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[969b3fe] | 449 | // Timers can apparently be marked as sent for the kernel |
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| 450 | // In either case, tick preemption |
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[8cb529e] | 451 | case SI_TIMER: |
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| 452 | case SI_KERNEL: |
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[169d944] | 453 | // __cfaabi_dbg_print_safe( "Kernel : Preemption thread tick\n" ); |
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[36982fc] | 454 | lock( event_kernel->lock __cfaabi_dbg_ctx2 ); |
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[9b1dcc2] | 455 | tick_preemption( &id ); |
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[ea7d2b0] | 456 | unlock( event_kernel->lock ); |
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[8cb529e] | 457 | break; |
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[969b3fe] | 458 | // Signal was not sent by the kernel but by an other thread |
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[8cb529e] | 459 | case SI_QUEUE: |
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[969b3fe] | 460 | // For now, other thread only signal the alarm thread to shut it down |
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| 461 | // If this needs to change use info.si_value and handle the case here |
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[8cb529e] | 462 | goto EXIT; |
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[cd17862] | 463 | } |
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| 464 | } |
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[a0b3e32] | 465 | |
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[8cb529e] | 466 | EXIT: |
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[169d944] | 467 | __cfaabi_dbg_print_safe( "Kernel : Preemption thread stopping\n" ); |
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[9b1dcc2] | 468 | unregister(&id); |
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[27f5f71] | 469 | return 0p; |
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[82ff5845] | 470 | } |
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| 471 | |
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[b68fc85] | 472 | //============================================================================================= |
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| 473 | // Kernel Signal Debug |
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| 474 | //============================================================================================= |
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| 475 | |
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| 476 | void __cfaabi_check_preemption() { |
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[14a61b5] | 477 | bool ready = kernelTLS.preemption_state.enabled; |
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[b68fc85] | 478 | if(!ready) { abort("Preemption should be ready"); } |
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| 479 | |
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| 480 | sigset_t oldset; |
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| 481 | int ret; |
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[27f5f71] | 482 | ret = pthread_sigmask(0, 0p, &oldset); |
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[b68fc85] | 483 | if(ret != 0) { abort("ERROR sigprocmask returned %d", ret); } |
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| 484 | |
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| 485 | ret = sigismember(&oldset, SIGUSR1); |
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| 486 | if(ret < 0) { abort("ERROR sigismember returned %d", ret); } |
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| 487 | if(ret == 1) { abort("ERROR SIGUSR1 is disabled"); } |
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[a83ffa4] | 488 | |
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| 489 | ret = sigismember(&oldset, SIGALRM); |
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| 490 | if(ret < 0) { abort("ERROR sigismember returned %d", ret); } |
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| 491 | if(ret == 0) { abort("ERROR SIGALRM is enabled"); } |
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| 492 | |
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| 493 | ret = sigismember(&oldset, SIGTERM); |
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| 494 | if(ret < 0) { abort("ERROR sigismember returned %d", ret); } |
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| 495 | if(ret == 1) { abort("ERROR SIGTERM is disabled"); } |
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[b68fc85] | 496 | } |
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| 497 | |
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[ea8b2f7] | 498 | #ifdef __CFA_WITH_VERIFY__ |
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| 499 | bool __cfaabi_dbg_in_kernel() { |
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| 500 | return !kernelTLS.preemption_state.enabled; |
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| 501 | } |
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| 502 | #endif |
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| 503 | |
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[6b0b624] | 504 | // Local Variables: // |
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| 505 | // mode: c // |
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| 506 | // tab-width: 4 // |
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| 507 | // End: // |
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