[6a3d2e7] | 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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[75a17f1] | 7 | // coroutine.c -- |
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[6a3d2e7] | 8 | // |
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| 9 | // Author : Thierry Delisle |
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| 10 | // Created On : Mon Nov 28 12:27:26 2016 |
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[6b0b624] | 11 | // Last Modified By : Peter A. Buhr |
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[b10affd] | 12 | // Last Modified On : Fri Mar 30 17:20:57 2018 |
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| 13 | // Update Count : 9 |
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[6a3d2e7] | 14 | // |
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| 15 | |
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[58b6d1b] | 16 | #include "coroutine.hfa" |
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[bd98b58] | 17 | |
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[6a3d2e7] | 18 | extern "C" { |
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| 19 | #include <stddef.h> |
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| 20 | #include <malloc.h> |
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| 21 | #include <errno.h> |
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| 22 | #include <string.h> |
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| 23 | #include <unistd.h> |
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[76e069f] | 24 | // use this define to make unwind.h play nice, definetely a hack |
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| 25 | #define HIDE_EXPORTS |
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| 26 | #include <unwind.h> |
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| 27 | #undef HIDE_EXPORTS |
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[6a3d2e7] | 28 | #include <sys/mman.h> |
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| 29 | } |
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| 30 | |
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[73abe95] | 31 | #include "kernel_private.hfa" |
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[6a3d2e7] | 32 | |
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| 33 | #define __CFA_INVOKE_PRIVATE__ |
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| 34 | #include "invoke.h" |
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| 35 | |
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[76e069f] | 36 | extern "C" { |
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[b2f6113] | 37 | void _CtxCoroutine_Unwind(struct _Unwind_Exception * storage, struct coroutine_desc *) __attribute__ ((__noreturn__)); |
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| 38 | static void _CtxCoroutine_UnwindCleanup(_Unwind_Reason_Code, struct _Unwind_Exception *) __attribute__ ((__noreturn__)); |
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| 39 | static void _CtxCoroutine_UnwindCleanup(_Unwind_Reason_Code, struct _Unwind_Exception *) { |
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| 40 | abort(); |
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| 41 | } |
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[76e069f] | 42 | } |
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| 43 | |
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[6a3d2e7] | 44 | //----------------------------------------------------------------------------- |
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| 45 | // Global state variables |
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| 46 | |
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| 47 | // minimum feasible stack size in bytes |
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| 48 | #define MinStackSize 1000 |
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[b2f6113] | 49 | extern size_t __page_size; // architecture pagesize HACK, should go in proper runtime singleton |
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| 50 | |
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| 51 | void __stack_prepare( __stack_info_t * this, size_t create_size ); |
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[6a3d2e7] | 52 | |
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| 53 | //----------------------------------------------------------------------------- |
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| 54 | // Coroutine ctors and dtors |
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[b2f6113] | 55 | void ?{}( __stack_info_t & this, void * storage, size_t storageSize ) { |
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| 56 | this.storage = (__stack_t *)storage; |
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| 57 | |
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| 58 | // Did we get a piece of storage ? |
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| 59 | if (this.storage || storageSize != 0) { |
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| 60 | // We either got a piece of storage or the user asked for a specific size |
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| 61 | // Immediately create the stack |
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| 62 | // (This is slightly unintuitive that non-default sized coroutines create are eagerly created |
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| 63 | // but it avoids that all coroutines carry an unnecessary size) |
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| 64 | verify( storageSize != 0 ); |
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| 65 | __stack_prepare( &this, storageSize ); |
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| 66 | } |
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[6a3d2e7] | 67 | } |
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| 68 | |
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[b2f6113] | 69 | void ^?{}(__stack_info_t & this) { |
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| 70 | if ( ! this.userStack && this.storage ) { |
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| 71 | void * storage = (char*)(this.storage) - this.storage->size; |
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| 72 | __cfaabi_dbg_debug_do( |
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| 73 | storage = (char*)(storage) - __page_size; |
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| 74 | if ( mprotect( storage, __page_size, PROT_READ | PROT_WRITE ) == -1 ) { |
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| 75 | abort( "(coStack_t *)%p.^?{}() : internal error, mprotect failure, error(%d) %s.", &this, errno, strerror( errno ) ); |
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| 76 | } |
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| 77 | ); |
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| 78 | __cfaabi_dbg_print_safe("Kernel : Deleting stack %p\n", storage); |
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| 79 | free( storage ); |
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| 80 | } |
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[6a3d2e7] | 81 | } |
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| 82 | |
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[de6319f] | 83 | void ?{}( coroutine_desc & this, const char * name, void * storage, size_t storageSize ) with( this ) { |
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[b2f6113] | 84 | (this.stack){storage, storageSize}; |
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| 85 | this.name = name; |
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| 86 | state = Start; |
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| 87 | starter = NULL; |
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| 88 | last = NULL; |
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| 89 | cancellation = NULL; |
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[6a3d2e7] | 90 | } |
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| 91 | |
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[76e069f] | 92 | void ^?{}(coroutine_desc& this) { |
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[b2f6113] | 93 | if(this.state != Halted && this.state != Start) { |
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| 94 | coroutine_desc * src = TL_GET( this_thread )->curr_cor; |
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| 95 | coroutine_desc * dst = &this; |
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| 96 | |
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| 97 | struct _Unwind_Exception storage; |
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| 98 | storage.exception_class = -1; |
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| 99 | storage.exception_cleanup = _CtxCoroutine_UnwindCleanup; |
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| 100 | this.cancellation = &storage; |
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| 101 | this.last = src; |
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| 102 | |
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| 103 | // not resuming self ? |
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| 104 | if ( src == dst ) { |
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| 105 | abort( "Attempt by coroutine %.256s (%p) to terminate itself.\n", src->name, src ); |
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| 106 | } |
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| 107 | |
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| 108 | CoroutineCtxSwitch( src, dst ); |
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| 109 | } |
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[76e069f] | 110 | } |
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[6a3d2e7] | 111 | |
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| 112 | // Part of the Public API |
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| 113 | // Not inline since only ever called once per coroutine |
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| 114 | forall(dtype T | is_coroutine(T)) |
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[83a071f9] | 115 | void prime(T& cor) { |
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[b2f6113] | 116 | coroutine_desc* this = get_coroutine(cor); |
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| 117 | assert(this->state == Start); |
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[6a3d2e7] | 118 | |
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[b2f6113] | 119 | this->state = Primed; |
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| 120 | resume(cor); |
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[6a3d2e7] | 121 | } |
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| 122 | |
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[0c92c9f] | 123 | // Wrapper for co |
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[c3acb841] | 124 | void CoroutineCtxSwitch(coroutine_desc* src, coroutine_desc* dst) { |
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[b2f6113] | 125 | // Safety note : Preemption must be disabled since there is a race condition |
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| 126 | // kernelTLS.this_thread->curr_cor and $rsp/$rbp must agree at all times |
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| 127 | verify( TL_GET( preemption_state.enabled ) || TL_GET( this_processor )->do_terminate ); |
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| 128 | disable_interrupts(); |
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[6a3d2e7] | 129 | |
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[b2f6113] | 130 | // set state of current coroutine to inactive |
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| 131 | src->state = src->state == Halted ? Halted : Inactive; |
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[de6319f] | 132 | |
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[b2f6113] | 133 | // set new coroutine that task is executing |
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| 134 | TL_GET( this_thread )->curr_cor = dst; |
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[de6319f] | 135 | |
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[b2f6113] | 136 | // context switch to specified coroutine |
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| 137 | CtxSwitch( &src->context, &dst->context ); |
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| 138 | // when CtxSwitch returns we are back in the src coroutine |
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[6a3d2e7] | 139 | |
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[b2f6113] | 140 | // set state of new coroutine to active |
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| 141 | src->state = Active; |
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[6a3d2e7] | 142 | |
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[b2f6113] | 143 | enable_interrupts( __cfaabi_dbg_ctx ); |
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| 144 | verify( TL_GET( preemption_state.enabled ) || TL_GET( this_processor )->do_terminate ); |
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[47ecf2b] | 145 | |
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[b2f6113] | 146 | if( unlikely(src->cancellation != NULL) ) { |
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| 147 | _CtxCoroutine_Unwind(src->cancellation, src); |
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| 148 | } |
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| 149 | } |
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[6a3d2e7] | 150 | |
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[b2f6113] | 151 | [void *, size_t] __stack_alloc( size_t storageSize ) { |
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| 152 | static const size_t stack_data_size = libCeiling( sizeof(__stack_t), 16 ); // minimum alignment |
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| 153 | assert(__page_size != 0l); |
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| 154 | size_t size = libCeiling( storageSize, 16 ) + stack_data_size; |
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| 155 | |
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| 156 | // If we are running debug, we also need to allocate a guardpage to catch stack overflows. |
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| 157 | void * storage; |
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| 158 | __cfaabi_dbg_debug_do( |
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| 159 | storage = memalign( __page_size, size + __page_size ); |
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| 160 | ); |
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| 161 | __cfaabi_dbg_no_debug_do( |
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| 162 | storage = (void*)malloc(size); |
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| 163 | ); |
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| 164 | |
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| 165 | __cfaabi_dbg_print_safe("Kernel : Created stack %p of size %zu\n", storage, size); |
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| 166 | __cfaabi_dbg_debug_do( |
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| 167 | if ( mprotect( storage, __page_size, PROT_NONE ) == -1 ) { |
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| 168 | abort( "__stack_alloc : internal error, mprotect failure, error(%d) %s.", (int)errno, strerror( (int)errno ) ); |
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| 169 | } |
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| 170 | storage = (void *)(((intptr_t)storage) + __page_size); |
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| 171 | ); |
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| 172 | |
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| 173 | verify( ((intptr_t)storage & (libAlign() - 1)) == 0ul ); |
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| 174 | return [storage, size]; |
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| 175 | } |
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[6a3d2e7] | 176 | |
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[b2f6113] | 177 | void __stack_prepare( __stack_info_t * this, size_t create_size ) { |
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| 178 | static const size_t stack_data_size = libCeiling( sizeof(__stack_t), 16 ); // minimum alignment |
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| 179 | bool userStack; |
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| 180 | void * storage; |
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| 181 | size_t size; |
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| 182 | if ( !this->storage ) { |
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| 183 | userStack = false; |
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| 184 | [storage, size] = __stack_alloc( create_size ); |
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| 185 | } else { |
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| 186 | userStack = true; |
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| 187 | __cfaabi_dbg_print_safe("Kernel : stack obj %p using user stack %p(%zu bytes)\n", this, this->storage, this->storage->size); |
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| 188 | |
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| 189 | // The stack must be aligned, advance the pointer to the next align data |
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| 190 | storage = (void*)libCeiling( (intptr_t)this->storage, libAlign()); |
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| 191 | |
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| 192 | // The size needs to be shrinked to fit all the extra data structure and be aligned |
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| 193 | ptrdiff_t diff = (intptr_t)storage - (intptr_t)this->storage; |
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| 194 | size = libFloor(create_size - stack_data_size - diff, libAlign()); |
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| 195 | } // if |
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| 196 | assertf( size >= MinStackSize, "Stack size %zd provides less than minimum of %d bytes for a stack.", size, MinStackSize ); |
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| 197 | |
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| 198 | this->storage = (__stack_t *)((intptr_t)storage + size); |
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| 199 | this->storage->size = size; |
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| 200 | this->storage->limit = storage; |
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| 201 | this->storage->base = (void*)((intptr_t)storage + size); |
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| 202 | this->userStack = userStack; |
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[6a3d2e7] | 203 | } |
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| 204 | |
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[0c92c9f] | 205 | // We need to call suspend from invoke.c, so we expose this wrapper that |
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| 206 | // is not inline (We can't inline Cforall in C) |
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| 207 | extern "C" { |
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[b2f6113] | 208 | void __suspend_internal(void) { |
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| 209 | suspend(); |
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| 210 | } |
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| 211 | |
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| 212 | void __leave_coroutine( coroutine_desc * src ) { |
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| 213 | coroutine_desc * starter = src->cancellation != 0 ? src->last : src->starter; |
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| 214 | |
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| 215 | src->state = Halted; |
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| 216 | |
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| 217 | assertf( starter != 0, |
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| 218 | "Attempt to suspend/leave coroutine \"%.256s\" (%p) that has never been resumed.\n" |
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| 219 | "Possible cause is a suspend executed in a member called by a coroutine user rather than by the coroutine main.", |
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| 220 | src->name, src ); |
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| 221 | assertf( starter->state != Halted, |
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| 222 | "Attempt by coroutine \"%.256s\" (%p) to suspend/leave back to terminated coroutine \"%.256s\" (%p).\n" |
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| 223 | "Possible cause is terminated coroutine's main routine has already returned.", |
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| 224 | src->name, src, starter->name, starter ); |
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| 225 | |
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| 226 | CoroutineCtxSwitch( src, starter ); |
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| 227 | } |
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[0c92c9f] | 228 | } |
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| 229 | |
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[6a3d2e7] | 230 | // Local Variables: // |
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| 231 | // mode: c // |
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| 232 | // tab-width: 4 // |
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[4aa2fb2] | 233 | // End: // |
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