[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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[e9b49379] | 12 | // Last Modified On : Wed Aug 26 16:46:03 2020 |
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| 13 | // Update Count : 53 |
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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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[e660761] | 28 | #include "kernel_private.hfa" |
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[82ff5845] | 29 | |
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[d8548e2] | 30 | #if !defined(__CFA_DEFAULT_PREEMPTION__) |
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[2a84d06d] | 31 | #define __CFA_DEFAULT_PREEMPTION__ 10`ms |
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[d8548e2] | 32 | #endif |
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[c81ebf9] | 33 | |
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[2a84d06d] | 34 | Duration default_preemption() __attribute__((weak)) { |
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[c81ebf9] | 35 | return __CFA_DEFAULT_PREEMPTION__; |
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| 36 | } |
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| 37 | |
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[969b3fe] | 38 | // FwdDeclarations : timeout handlers |
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[c81ebf9] | 39 | static void preempt( processor * this ); |
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[e873838] | 40 | static void timeout( $thread * this ); |
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[c81ebf9] | 41 | |
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[969b3fe] | 42 | // FwdDeclarations : Signal handlers |
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[c29c342] | 43 | static void sigHandler_ctxSwitch( __CFA_SIGPARMS__ ); |
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[c59a346] | 44 | static void sigHandler_alarm ( __CFA_SIGPARMS__ ); |
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[c29c342] | 45 | static void sigHandler_segv ( __CFA_SIGPARMS__ ); |
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| 46 | static void sigHandler_ill ( __CFA_SIGPARMS__ ); |
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| 47 | static void sigHandler_fpe ( __CFA_SIGPARMS__ ); |
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| 48 | static void sigHandler_abort ( __CFA_SIGPARMS__ ); |
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[82ff5845] | 49 | |
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[969b3fe] | 50 | // FwdDeclarations : alarm thread main |
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[c29c342] | 51 | static void * alarm_loop( __attribute__((unused)) void * args ); |
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[969b3fe] | 52 | |
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| 53 | // Machine specific register name |
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[381fdee] | 54 | #if defined( __i386 ) |
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[b2b44d8] | 55 | #define CFA_REG_IP gregs[REG_EIP] |
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[381fdee] | 56 | #elif defined( __x86_64 ) |
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| 57 | #define CFA_REG_IP gregs[REG_RIP] |
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[e9b49379] | 58 | #elif defined( __arm__ ) |
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| 59 | #define CFA_REG_IP arm_pc |
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| 60 | #elif defined( __aarch64__ ) |
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[482fa08] | 61 | #define CFA_REG_IP pc |
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[381fdee] | 62 | #else |
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[e9b49379] | 63 | #error unsupported hardware architecture |
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[cd17862] | 64 | #endif |
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| 65 | |
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[969b3fe] | 66 | KERNEL_STORAGE(event_kernel_t, event_kernel); // private storage for event kernel |
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| 67 | event_kernel_t * event_kernel; // kernel public handle to even kernel |
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| 68 | static pthread_t alarm_thread; // pthread handle to alarm thread |
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[09d4b22] | 69 | static void * alarm_stack; // pthread stack for alarm thread |
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[969b3fe] | 70 | |
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[c29c342] | 71 | static void ?{}(event_kernel_t & this) with( this ) { |
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[65deb18] | 72 | alarms{}; |
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| 73 | lock{}; |
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[969b3fe] | 74 | } |
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[82ff5845] | 75 | |
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[4dad189] | 76 | enum { |
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| 77 | PREEMPT_NORMAL = 0, |
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| 78 | PREEMPT_TERMINATE = 1, |
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| 79 | }; |
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| 80 | |
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[c81ebf9] | 81 | //============================================================================================= |
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| 82 | // Kernel Preemption logic |
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| 83 | //============================================================================================= |
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| 84 | |
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[969b3fe] | 85 | // Get next expired node |
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[2a84d06d] | 86 | static inline alarm_node_t * get_expired( alarm_list_t * alarms, Time currtime ) { |
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[d3ab183] | 87 | if( ! & (*alarms)`first ) return 0p; // If no alarms return null |
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| 88 | if( (*alarms)`first.alarm >= currtime ) return 0p; // If alarms head not expired return null |
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[27f5f71] | 89 | return pop(alarms); // Otherwise just pop head |
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[969b3fe] | 90 | } |
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| 91 | |
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| 92 | // Tick one frame of the Discrete Event Simulation for alarms |
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[e873838] | 93 | static void tick_preemption(void) { |
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[27f5f71] | 94 | alarm_node_t * node = 0p; // Used in the while loop but cannot be declared in the while condition |
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| 95 | alarm_list_t * alarms = &event_kernel->alarms; // Local copy for ease of reading |
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| 96 | Time currtime = __kernel_get_time(); // Check current time once so everything "happens at once" |
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[8cb529e] | 97 | |
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[969b3fe] | 98 | //Loop throught every thing expired |
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| 99 | while( node = get_expired( alarms, currtime ) ) { |
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[b1a4300] | 100 | // __cfaabi_dbg_print_buffer_decl( " KERNEL: preemption tick.\n" ); |
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[185efe6] | 101 | Duration period = node->period; |
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| 102 | if( period == 0) { |
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| 103 | node->set = false; // Node is one-shot, just mark it as not pending |
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| 104 | } |
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[1c273d0] | 105 | |
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[969b3fe] | 106 | // Check if this is a kernel |
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[4b30e8cc] | 107 | if( node->type == Kernel ) { |
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[c81ebf9] | 108 | preempt( node->proc ); |
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| 109 | } |
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[4b30e8cc] | 110 | else if( node->type == User ) { |
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[e873838] | 111 | timeout( node->thrd ); |
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[c81ebf9] | 112 | } |
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[4b30e8cc] | 113 | else { |
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[eeb5023] | 114 | node->callback(*node); |
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[4b30e8cc] | 115 | } |
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[c81ebf9] | 116 | |
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[969b3fe] | 117 | // Check if this is a periodic alarm |
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[8cb529e] | 118 | if( period > 0 ) { |
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[b1a4300] | 119 | // __cfaabi_dbg_print_buffer_local( " KERNEL: alarm period is %lu.\n", period.tv ); |
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[969b3fe] | 120 | node->alarm = currtime + period; // Alarm is periodic, add currtime to it (used cached current time) |
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| 121 | insert( alarms, node ); // Reinsert the node for the next time it triggers |
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[c81ebf9] | 122 | } |
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| 123 | } |
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| 124 | |
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[969b3fe] | 125 | // If there are still alarms pending, reset the timer |
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[d3ab183] | 126 | if( & (*alarms)`first ) { |
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[6a490b2] | 127 | __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] | 128 | Duration delta = (*alarms)`first.alarm - currtime; |
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| 129 | Duration capped = max(delta, 50`us); |
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[b1a4300] | 130 | // itimerval tim = { caped }; |
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| 131 | // __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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| 132 | |
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[d3ab183] | 133 | __kernel_set_timer( capped ); |
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[b1a4300] | 134 | } |
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[c81ebf9] | 135 | } |
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| 136 | |
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[969b3fe] | 137 | // Update the preemption of a processor and notify interested parties |
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[2a84d06d] | 138 | void update_preemption( processor * this, Duration duration ) { |
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[c81ebf9] | 139 | alarm_node_t * alarm = this->preemption_alarm; |
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| 140 | |
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| 141 | // Alarms need to be enabled |
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[2a84d06d] | 142 | if ( duration > 0 && ! alarm->set ) { |
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[c81ebf9] | 143 | alarm->alarm = __kernel_get_time() + duration; |
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| 144 | alarm->period = duration; |
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| 145 | register_self( alarm ); |
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| 146 | } |
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[8ad6533] | 147 | // Zero duration but alarm is set |
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[c81ebf9] | 148 | else if ( duration == 0 && alarm->set ) { |
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| 149 | unregister_self( alarm ); |
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| 150 | alarm->alarm = 0; |
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| 151 | alarm->period = 0; |
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| 152 | } |
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| 153 | // If alarm is different from previous, change it |
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| 154 | else if ( duration > 0 && alarm->period != duration ) { |
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| 155 | unregister_self( alarm ); |
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| 156 | alarm->alarm = __kernel_get_time() + duration; |
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| 157 | alarm->period = duration; |
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| 158 | register_self( alarm ); |
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| 159 | } |
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| 160 | } |
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| 161 | |
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| 162 | //============================================================================================= |
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[cd17862] | 163 | // Kernel Signal Tools |
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[c81ebf9] | 164 | //============================================================================================= |
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| 165 | |
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[36982fc] | 166 | __cfaabi_dbg_debug_do( static thread_local void * last_interrupt = 0; ) |
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[b227f68] | 167 | |
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[82ff5845] | 168 | extern "C" { |
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[969b3fe] | 169 | // Disable interrupts by incrementing the counter |
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[82ff5845] | 170 | void disable_interrupts() { |
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[afd550c] | 171 | with( kernelTLS.preemption_state ) { |
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[1f81d61] | 172 | #if GCC_VERSION > 50000 |
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[13073be] | 173 | static_assert(__atomic_always_lock_free(sizeof(enabled), &enabled), "Must be lock-free"); |
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[1f81d61] | 174 | #endif |
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[13073be] | 175 | |
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| 176 | // Set enabled flag to false |
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| 177 | // should be atomic to avoid preemption in the middle of the operation. |
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| 178 | // use memory order RELAXED since there is no inter-thread on this variable requirements |
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| 179 | __atomic_store_n(&enabled, false, __ATOMIC_RELAXED); |
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| 180 | |
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| 181 | // Signal the compiler that a fence is needed but only for signal handlers |
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| 182 | __atomic_signal_fence(__ATOMIC_ACQUIRE); |
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| 183 | |
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[de6319f] | 184 | __attribute__((unused)) unsigned short new_val = disable_count + 1; |
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| 185 | disable_count = new_val; |
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| 186 | verify( new_val < 65_000u ); // If this triggers someone is disabling interrupts without enabling them |
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| 187 | } |
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[82ff5845] | 188 | } |
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| 189 | |
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[969b3fe] | 190 | // Enable interrupts by decrementing the counter |
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[c7a900a] | 191 | // If counter reaches 0, execute any pending __cfactx_switch |
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[36982fc] | 192 | void enable_interrupts( __cfaabi_dbg_ctx_param ) { |
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[13073be] | 193 | processor * proc = kernelTLS.this_processor; // Cache the processor now since interrupts can start happening after the atomic store |
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[8e9e9a2] | 194 | /* paranoid */ verify( proc ); |
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[969b3fe] | 195 | |
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[afd550c] | 196 | with( kernelTLS.preemption_state ){ |
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[de6319f] | 197 | unsigned short prev = disable_count; |
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| 198 | disable_count -= 1; |
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| 199 | verify( prev != 0u ); // If this triggers someone is enabled already enabled interruptsverify( prev != 0u ); |
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| 200 | |
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| 201 | // Check if we need to prempt the thread because an interrupt was missed |
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| 202 | if( prev == 1 ) { |
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[1f81d61] | 203 | #if GCC_VERSION > 50000 |
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[13073be] | 204 | static_assert(__atomic_always_lock_free(sizeof(enabled), &enabled), "Must be lock-free"); |
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[1f81d61] | 205 | #endif |
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[13073be] | 206 | |
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| 207 | // Set enabled flag to true |
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| 208 | // should be atomic to avoid preemption in the middle of the operation. |
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| 209 | // use memory order RELAXED since there is no inter-thread on this variable requirements |
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| 210 | __atomic_store_n(&enabled, true, __ATOMIC_RELAXED); |
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| 211 | |
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| 212 | // Signal the compiler that a fence is needed but only for signal handlers |
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| 213 | __atomic_signal_fence(__ATOMIC_RELEASE); |
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[de6319f] | 214 | if( proc->pending_preemption ) { |
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| 215 | proc->pending_preemption = false; |
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[3381ed7] | 216 | force_yield( __POLL_PREEMPTION ); |
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[de6319f] | 217 | } |
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[d0a045c7] | 218 | } |
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[82ff5845] | 219 | } |
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[4e6fb8e] | 220 | |
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[969b3fe] | 221 | // For debugging purposes : keep track of the last person to enable the interrupts |
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[36982fc] | 222 | __cfaabi_dbg_debug_do( proc->last_enable = caller; ) |
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[82ff5845] | 223 | } |
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[969b3fe] | 224 | |
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| 225 | // Disable interrupts by incrementint the counter |
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[c7a900a] | 226 | // Don't execute any pending __cfactx_switch even if counter reaches 0 |
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[969b3fe] | 227 | void enable_interrupts_noPoll() { |
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[afd550c] | 228 | unsigned short prev = kernelTLS.preemption_state.disable_count; |
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| 229 | kernelTLS.preemption_state.disable_count -= 1; |
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[2e9aed4] | 230 | verifyf( prev != 0u, "Incremented from %u\n", prev ); // If this triggers someone is enabled already enabled interrupts |
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[d0a045c7] | 231 | if( prev == 1 ) { |
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[1f81d61] | 232 | #if GCC_VERSION > 50000 |
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[13073be] | 233 | static_assert(__atomic_always_lock_free(sizeof(kernelTLS.preemption_state.enabled), &kernelTLS.preemption_state.enabled), "Must be lock-free"); |
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[1f81d61] | 234 | #endif |
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[13073be] | 235 | // Set enabled flag to true |
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| 236 | // should be atomic to avoid preemption in the middle of the operation. |
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| 237 | // use memory order RELAXED since there is no inter-thread on this variable requirements |
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| 238 | __atomic_store_n(&kernelTLS.preemption_state.enabled, true, __ATOMIC_RELAXED); |
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| 239 | |
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| 240 | // Signal the compiler that a fence is needed but only for signal handlers |
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| 241 | __atomic_signal_fence(__ATOMIC_RELEASE); |
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[d0a045c7] | 242 | } |
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[969b3fe] | 243 | } |
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[82ff5845] | 244 | } |
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| 245 | |
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[969b3fe] | 246 | // sigprocmask wrapper : unblock a single signal |
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[1c273d0] | 247 | static inline void signal_unblock( int sig ) { |
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[82ff5845] | 248 | sigset_t mask; |
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| 249 | sigemptyset( &mask ); |
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[1c273d0] | 250 | sigaddset( &mask, sig ); |
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[82ff5845] | 251 | |
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[27f5f71] | 252 | if ( pthread_sigmask( SIG_UNBLOCK, &mask, 0p ) == -1 ) { |
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[169d944] | 253 | abort( "internal error, pthread_sigmask" ); |
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[cd17862] | 254 | } |
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[82ff5845] | 255 | } |
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| 256 | |
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[969b3fe] | 257 | // sigprocmask wrapper : block a single signal |
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[cd17862] | 258 | static inline void signal_block( int sig ) { |
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| 259 | sigset_t mask; |
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| 260 | sigemptyset( &mask ); |
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| 261 | sigaddset( &mask, sig ); |
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[47ecf2b] | 262 | |
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[27f5f71] | 263 | if ( pthread_sigmask( SIG_BLOCK, &mask, 0p ) == -1 ) { |
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[c59a346] | 264 | abort( "internal error, pthread_sigmask" ); |
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[cd17862] | 265 | } |
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| 266 | } |
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[47ecf2b] | 267 | |
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[969b3fe] | 268 | // kill wrapper : signal a processor |
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[cd17862] | 269 | static void preempt( processor * this ) { |
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[4dad189] | 270 | sigval_t value = { PREEMPT_NORMAL }; |
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| 271 | pthread_sigqueue( this->kernel_thread, SIGUSR1, value ); |
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| 272 | } |
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| 273 | |
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[969b3fe] | 274 | // reserved for future use |
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[e873838] | 275 | static void timeout( $thread * this ) { |
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[8834751] | 276 | #if !defined( __CFA_NO_STATISTICS__ ) |
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| 277 | kernelTLS.this_stats = this->curr_cluster->stats; |
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| 278 | #endif |
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[e873838] | 279 | unpark( this ); |
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[cd17862] | 280 | } |
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| 281 | |
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[14a61b5] | 282 | // KERNEL ONLY |
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[c7a900a] | 283 | // Check if a __cfactx_switch signal handler shoud defer |
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[969b3fe] | 284 | // If true : preemption is safe |
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| 285 | // If false : preemption is unsafe and marked as pending |
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| 286 | static inline bool preemption_ready() { |
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[14a61b5] | 287 | // Check if preemption is safe |
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| 288 | bool ready = kernelTLS.preemption_state.enabled && ! kernelTLS.preemption_state.in_progress; |
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| 289 | |
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| 290 | // Adjust the pending flag accordingly |
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| 291 | kernelTLS.this_processor->pending_preemption = !ready; |
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[969b3fe] | 292 | return ready; |
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| 293 | } |
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| 294 | |
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[cd17862] | 295 | //============================================================================================= |
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| 296 | // Kernel Signal Startup/Shutdown logic |
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| 297 | //============================================================================================= |
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| 298 | |
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[969b3fe] | 299 | // Startup routine to activate preemption |
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| 300 | // Called from kernel_startup |
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[e660761] | 301 | void __kernel_alarm_startup() { |
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[169d944] | 302 | __cfaabi_dbg_print_safe( "Kernel : Starting preemption\n" ); |
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[969b3fe] | 303 | |
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| 304 | // Start with preemption disabled until ready |
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[14a61b5] | 305 | kernelTLS.preemption_state.enabled = false; |
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| 306 | kernelTLS.preemption_state.disable_count = 1; |
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[969b3fe] | 307 | |
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| 308 | // Initialize the event kernel |
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| 309 | event_kernel = (event_kernel_t *)&storage_event_kernel; |
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[9236060] | 310 | (*event_kernel){}; |
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[969b3fe] | 311 | |
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| 312 | // Setup proper signal handlers |
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[c7a900a] | 313 | __cfaabi_sigaction( SIGUSR1, sigHandler_ctxSwitch, SA_SIGINFO | SA_RESTART ); // __cfactx_switch handler |
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[c59a346] | 314 | __cfaabi_sigaction( SIGALRM, sigHandler_alarm , SA_SIGINFO | SA_RESTART ); // debug handler |
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[cd17862] | 315 | |
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| 316 | signal_block( SIGALRM ); |
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| 317 | |
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[8c50aed] | 318 | alarm_stack = __create_pthread( &alarm_thread, alarm_loop, 0p ); |
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[cd17862] | 319 | } |
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| 320 | |
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[969b3fe] | 321 | // Shutdown routine to deactivate preemption |
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| 322 | // Called from kernel_shutdown |
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[e660761] | 323 | void __kernel_alarm_shutdown() { |
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[169d944] | 324 | __cfaabi_dbg_print_safe( "Kernel : Preemption stopping\n" ); |
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[d6ff3ff] | 325 | |
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[969b3fe] | 326 | // Block all signals since we are already shutting down |
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[cd17862] | 327 | sigset_t mask; |
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| 328 | sigfillset( &mask ); |
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[27f5f71] | 329 | sigprocmask( SIG_BLOCK, &mask, 0p ); |
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[cd17862] | 330 | |
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[969b3fe] | 331 | // Notify the alarm thread of the shutdown |
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[a0b3e32] | 332 | sigval val = { 1 }; |
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| 333 | pthread_sigqueue( alarm_thread, SIGALRM, val ); |
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[969b3fe] | 334 | |
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| 335 | // Wait for the preemption thread to finish |
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[27f5f71] | 336 | |
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| 337 | pthread_join( alarm_thread, 0p ); |
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[09d4b22] | 338 | free( alarm_stack ); |
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[969b3fe] | 339 | |
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| 340 | // Preemption is now fully stopped |
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| 341 | |
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[169d944] | 342 | __cfaabi_dbg_print_safe( "Kernel : Preemption stopped\n" ); |
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[cd17862] | 343 | } |
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| 344 | |
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[969b3fe] | 345 | // Raii ctor/dtor for the preemption_scope |
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| 346 | // Used by thread to control when they want to receive preemption signals |
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[242a902] | 347 | void ?{}( preemption_scope & this, processor * proc ) { |
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[2a84d06d] | 348 | (this.alarm){ proc, (Time){ 0 }, 0`s }; |
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[242a902] | 349 | this.proc = proc; |
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| 350 | this.proc->preemption_alarm = &this.alarm; |
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[969b3fe] | 351 | |
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[d8548e2] | 352 | update_preemption( this.proc, this.proc->cltr->preemption_rate ); |
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[cd17862] | 353 | } |
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| 354 | |
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[242a902] | 355 | void ^?{}( preemption_scope & this ) { |
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[cd17862] | 356 | disable_interrupts(); |
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| 357 | |
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[2a84d06d] | 358 | update_preemption( this.proc, 0`s ); |
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[cd17862] | 359 | } |
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| 360 | |
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| 361 | //============================================================================================= |
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| 362 | // Kernel Signal Handlers |
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| 363 | //============================================================================================= |
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[47ecf2b] | 364 | |
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[969b3fe] | 365 | // Context switch signal handler |
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| 366 | // Receives SIGUSR1 signal and causes the current thread to yield |
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[c29c342] | 367 | static void sigHandler_ctxSwitch( __CFA_SIGPARMS__ ) { |
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[b2b44d8] | 368 | __cfaabi_dbg_debug_do( last_interrupt = (void *)(cxt->uc_mcontext.CFA_REG_IP); ) |
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[969b3fe] | 369 | |
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[4dad189] | 370 | // SKULLDUGGERY: if a thread creates a processor and the immediately deletes it, |
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| 371 | // the interrupt that is supposed to force the kernel thread to preempt might arrive |
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[482fa08] | 372 | // before the kernel thread has even started running. When that happens, an interrupt |
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[97cba9f] | 373 | // with a null 'this_processor' will be caught, just ignore it. |
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[14a61b5] | 374 | if(! kernelTLS.this_processor ) return; |
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[4dad189] | 375 | |
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| 376 | choose(sfp->si_value.sival_int) { |
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| 377 | case PREEMPT_NORMAL : ;// Normal case, nothing to do here |
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[ea8b2f7] | 378 | case PREEMPT_TERMINATE: verify( __atomic_load_n( &kernelTLS.this_processor->do_terminate, __ATOMIC_SEQ_CST ) ); |
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[4dad189] | 379 | default: |
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[ff878b7] | 380 | abort( "internal error, signal value is %d", sfp->si_value.sival_int ); |
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[4dad189] | 381 | } |
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| 382 | |
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[b2b44d8] | 383 | // Check if it is safe to preempt here |
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[969b3fe] | 384 | if( !preemption_ready() ) { return; } |
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| 385 | |
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[b1a4300] | 386 | __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] | 387 | |
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| 388 | // Sync flag : prevent recursive calls to the signal handler |
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| 389 | kernelTLS.preemption_state.in_progress = true; |
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| 390 | |
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[a83ffa4] | 391 | // Clear sighandler mask before context switching. |
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[1f81d61] | 392 | #if GCC_VERSION > 50000 |
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[a83ffa4] | 393 | static_assert( sizeof( sigset_t ) == sizeof( cxt->uc_sigmask ), "Expected cxt->uc_sigmask to be of sigset_t" ); |
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[1f81d61] | 394 | #endif |
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[27f5f71] | 395 | if ( pthread_sigmask( SIG_SETMASK, (sigset_t *)&(cxt->uc_sigmask), 0p ) == -1 ) { |
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[a83ffa4] | 396 | abort( "internal error, sigprocmask" ); |
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| 397 | } |
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[05615ba] | 398 | |
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[14a61b5] | 399 | // TODO: this should go in finish action |
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| 400 | // Clear the in progress flag |
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| 401 | kernelTLS.preemption_state.in_progress = false; |
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[969b3fe] | 402 | |
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| 403 | // Preemption can occur here |
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| 404 | |
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[c7a900a] | 405 | force_yield( __ALARM_PREEMPTION ); // Do the actual __cfactx_switch |
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[c81ebf9] | 406 | } |
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| 407 | |
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[c59a346] | 408 | static void sigHandler_alarm( __CFA_SIGPARMS__ ) { |
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| 409 | abort("SIGALRM should never reach the signal handler"); |
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[c81ebf9] | 410 | } |
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| 411 | |
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[969b3fe] | 412 | // Main of the alarm thread |
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| 413 | // Waits on SIGALRM and send SIGUSR1 to whom ever needs it |
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[c29c342] | 414 | static void * alarm_loop( __attribute__((unused)) void * args ) { |
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[9b1dcc2] | 415 | __processor_id_t id; |
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[58d64a4] | 416 | id.full_proc = false; |
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[9b1dcc2] | 417 | id.id = doregister(&id); |
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[e873838] | 418 | kernelTLS.this_proc_id = &id; |
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[9b1dcc2] | 419 | |
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[969b3fe] | 420 | // Block sigalrms to control when they arrive |
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[cd17862] | 421 | sigset_t mask; |
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[ade5272] | 422 | sigfillset(&mask); |
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[27f5f71] | 423 | if ( pthread_sigmask( SIG_BLOCK, &mask, 0p ) == -1 ) { |
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[169d944] | 424 | abort( "internal error, pthread_sigmask" ); |
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[82ff5845] | 425 | } |
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[c81ebf9] | 426 | |
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[ade5272] | 427 | sigemptyset( &mask ); |
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| 428 | sigaddset( &mask, SIGALRM ); |
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| 429 | |
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[969b3fe] | 430 | // Main loop |
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[cd17862] | 431 | while( true ) { |
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[969b3fe] | 432 | // Wait for a sigalrm |
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[a0b3e32] | 433 | siginfo_t info; |
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| 434 | int sig = sigwaitinfo( &mask, &info ); |
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[969b3fe] | 435 | |
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[e2f7bc3] | 436 | if( sig < 0 ) { |
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| 437 | //Error! |
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| 438 | int err = errno; |
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| 439 | switch( err ) { |
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| 440 | case EAGAIN : |
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| 441 | case EINTR : |
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[b1a4300] | 442 | {__cfaabi_dbg_print_buffer_decl( " KERNEL: Spurious wakeup %d.\n", err );} |
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[e2f7bc3] | 443 | continue; |
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[27f5f71] | 444 | case EINVAL : |
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[169d944] | 445 | abort( "Timeout was invalid." ); |
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[e2f7bc3] | 446 | default: |
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[169d944] | 447 | abort( "Unhandled error %d", err); |
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[e2f7bc3] | 448 | } |
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| 449 | } |
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| 450 | |
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[969b3fe] | 451 | // If another signal arrived something went wrong |
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[8cb529e] | 452 | 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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| 453 | |
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[169d944] | 454 | // __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] | 455 | // Switch on the code (a.k.a. the sender) to |
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[8cb529e] | 456 | switch( info.si_code ) |
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[a0b3e32] | 457 | { |
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[969b3fe] | 458 | // Timers can apparently be marked as sent for the kernel |
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| 459 | // In either case, tick preemption |
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[8cb529e] | 460 | case SI_TIMER: |
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| 461 | case SI_KERNEL: |
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[169d944] | 462 | // __cfaabi_dbg_print_safe( "Kernel : Preemption thread tick\n" ); |
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[36982fc] | 463 | lock( event_kernel->lock __cfaabi_dbg_ctx2 ); |
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[e873838] | 464 | tick_preemption(); |
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[ea7d2b0] | 465 | unlock( event_kernel->lock ); |
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[8cb529e] | 466 | break; |
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[969b3fe] | 467 | // Signal was not sent by the kernel but by an other thread |
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[8cb529e] | 468 | case SI_QUEUE: |
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[969b3fe] | 469 | // For now, other thread only signal the alarm thread to shut it down |
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| 470 | // If this needs to change use info.si_value and handle the case here |
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[8cb529e] | 471 | goto EXIT; |
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[cd17862] | 472 | } |
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| 473 | } |
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[a0b3e32] | 474 | |
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[8cb529e] | 475 | EXIT: |
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[169d944] | 476 | __cfaabi_dbg_print_safe( "Kernel : Preemption thread stopping\n" ); |
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[9b1dcc2] | 477 | unregister(&id); |
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[27f5f71] | 478 | return 0p; |
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[82ff5845] | 479 | } |
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| 480 | |
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[b68fc85] | 481 | //============================================================================================= |
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| 482 | // Kernel Signal Debug |
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| 483 | //============================================================================================= |
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| 484 | |
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| 485 | void __cfaabi_check_preemption() { |
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[14a61b5] | 486 | bool ready = kernelTLS.preemption_state.enabled; |
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[b68fc85] | 487 | if(!ready) { abort("Preemption should be ready"); } |
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| 488 | |
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| 489 | sigset_t oldset; |
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| 490 | int ret; |
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[b81fd95] | 491 | ret = pthread_sigmask(0, ( const sigset_t * ) 0p, &oldset); // workaround trac#208: cast should be unnecessary |
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[b68fc85] | 492 | if(ret != 0) { abort("ERROR sigprocmask returned %d", ret); } |
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| 493 | |
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| 494 | ret = sigismember(&oldset, SIGUSR1); |
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| 495 | if(ret < 0) { abort("ERROR sigismember returned %d", ret); } |
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| 496 | if(ret == 1) { abort("ERROR SIGUSR1 is disabled"); } |
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[a83ffa4] | 497 | |
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| 498 | ret = sigismember(&oldset, SIGALRM); |
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| 499 | if(ret < 0) { abort("ERROR sigismember returned %d", ret); } |
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| 500 | if(ret == 0) { abort("ERROR SIGALRM is enabled"); } |
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| 501 | |
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| 502 | ret = sigismember(&oldset, SIGTERM); |
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| 503 | if(ret < 0) { abort("ERROR sigismember returned %d", ret); } |
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| 504 | if(ret == 1) { abort("ERROR SIGTERM is disabled"); } |
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[b68fc85] | 505 | } |
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| 506 | |
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[ea8b2f7] | 507 | #ifdef __CFA_WITH_VERIFY__ |
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| 508 | bool __cfaabi_dbg_in_kernel() { |
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| 509 | return !kernelTLS.preemption_state.enabled; |
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| 510 | } |
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| 511 | #endif |
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| 512 | |
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[6b0b624] | 513 | // Local Variables: // |
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| 514 | // mode: c // |
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| 515 | // tab-width: 4 // |
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| 516 | // End: // |
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