source: libcfa/src/concurrency/coroutine.cfa @ b2f6113

arm-ehcleanup-dtorsjacob/cs343-translationjenkins-sandboxnew-astnew-ast-unique-expr
Last change on this file since b2f6113 was b2f6113, checked in by tdelisle <tdelisle@…>, 3 years ago

Swapped memory storage for context and stack information inside the coroutine implementation

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1//
2// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
3//
4// The contents of this file are covered under the licence agreement in the
5// file "LICENCE" distributed with Cforall.
6//
7// coroutine.c --
8//
9// Author           : Thierry Delisle
10// Created On       : Mon Nov 28 12:27:26 2016
11// Last Modified By : Peter A. Buhr
12// Last Modified On : Fri Mar 30 17:20:57 2018
13// Update Count     : 9
14//
15
16#include "coroutine.hfa"
17
18extern "C" {
19#include <stddef.h>
20#include <malloc.h>
21#include <errno.h>
22#include <string.h>
23#include <unistd.h>
24// use this define to make unwind.h play nice, definetely a hack
25#define HIDE_EXPORTS
26#include <unwind.h>
27#undef HIDE_EXPORTS
28#include <sys/mman.h>
29}
30
31#include "kernel_private.hfa"
32
33#define __CFA_INVOKE_PRIVATE__
34#include "invoke.h"
35
36extern "C" {
37        void _CtxCoroutine_Unwind(struct _Unwind_Exception * storage, struct coroutine_desc *) __attribute__ ((__noreturn__));
38        static void _CtxCoroutine_UnwindCleanup(_Unwind_Reason_Code, struct _Unwind_Exception *) __attribute__ ((__noreturn__));
39        static void _CtxCoroutine_UnwindCleanup(_Unwind_Reason_Code, struct _Unwind_Exception *) {
40                abort();
41        }
42}
43
44//-----------------------------------------------------------------------------
45// Global state variables
46
47// minimum feasible stack size in bytes
48#define MinStackSize 1000
49extern size_t __page_size;                              // architecture pagesize HACK, should go in proper runtime singleton
50
51void __stack_prepare( __stack_info_t * this, size_t create_size );
52
53//-----------------------------------------------------------------------------
54// Coroutine ctors and dtors
55void ?{}( __stack_info_t & this, void * storage, size_t storageSize ) {
56        this.storage   = (__stack_t *)storage;
57
58        // Did we get a piece of storage ?
59        if (this.storage || storageSize != 0) {
60                // We either got a piece of storage or the user asked for a specific size
61                // Immediately create the stack
62                // (This is slightly unintuitive that non-default sized coroutines create are eagerly created
63                // but it avoids that all coroutines carry an unnecessary size)
64                verify( storageSize != 0 );
65                __stack_prepare( &this, storageSize );
66        }
67}
68
69void ^?{}(__stack_info_t & this) {
70        if ( ! this.userStack && this.storage ) {
71                void * storage = (char*)(this.storage) - this.storage->size;
72                __cfaabi_dbg_debug_do(
73                        storage = (char*)(storage) - __page_size;
74                        if ( mprotect( storage, __page_size, PROT_READ | PROT_WRITE ) == -1 ) {
75                                abort( "(coStack_t *)%p.^?{}() : internal error, mprotect failure, error(%d) %s.", &this, errno, strerror( errno ) );
76                        }
77                );
78                __cfaabi_dbg_print_safe("Kernel : Deleting stack %p\n", storage);
79                free( storage );
80        }
81}
82
83void ?{}( coroutine_desc & this, const char * name, void * storage, size_t storageSize ) with( this ) {
84        (this.stack){storage, storageSize};
85        this.name = name;
86        state = Start;
87        starter = NULL;
88        last = NULL;
89        cancellation = NULL;
90}
91
92void ^?{}(coroutine_desc& this) {
93        if(this.state != Halted && this.state != Start) {
94                coroutine_desc * src = TL_GET( this_thread )->curr_cor;
95                coroutine_desc * dst = &this;
96
97                struct _Unwind_Exception storage;
98                storage.exception_class = -1;
99                storage.exception_cleanup = _CtxCoroutine_UnwindCleanup;
100                this.cancellation = &storage;
101                this.last = src;
102
103                // not resuming self ?
104                if ( src == dst ) {
105                        abort( "Attempt by coroutine %.256s (%p) to terminate itself.\n", src->name, src );
106                }
107
108                CoroutineCtxSwitch( src, dst );
109        }
110}
111
112// Part of the Public API
113// Not inline since only ever called once per coroutine
114forall(dtype T | is_coroutine(T))
115void prime(T& cor) {
116        coroutine_desc* this = get_coroutine(cor);
117        assert(this->state == Start);
118
119        this->state = Primed;
120        resume(cor);
121}
122
123// Wrapper for co
124void CoroutineCtxSwitch(coroutine_desc* src, coroutine_desc* dst) {
125        // Safety note : Preemption must be disabled since there is a race condition
126        // kernelTLS.this_thread->curr_cor and $rsp/$rbp must agree at all times
127        verify( TL_GET( preemption_state.enabled ) || TL_GET( this_processor )->do_terminate );
128        disable_interrupts();
129
130        // set state of current coroutine to inactive
131        src->state = src->state == Halted ? Halted : Inactive;
132
133        // set new coroutine that task is executing
134        TL_GET( this_thread )->curr_cor = dst;
135
136        // context switch to specified coroutine
137        CtxSwitch( &src->context, &dst->context );
138        // when CtxSwitch returns we are back in the src coroutine
139
140        // set state of new coroutine to active
141        src->state = Active;
142
143        enable_interrupts( __cfaabi_dbg_ctx );
144        verify( TL_GET( preemption_state.enabled ) || TL_GET( this_processor )->do_terminate );
145
146        if( unlikely(src->cancellation != NULL) ) {
147                _CtxCoroutine_Unwind(src->cancellation, src);
148        }
149}
150
151[void *, size_t] __stack_alloc( size_t storageSize ) {
152        static const size_t stack_data_size = libCeiling( sizeof(__stack_t), 16 ); // minimum alignment
153        assert(__page_size != 0l);
154        size_t size = libCeiling( storageSize, 16 ) + stack_data_size;
155
156        // If we are running debug, we also need to allocate a guardpage to catch stack overflows.
157        void * storage;
158        __cfaabi_dbg_debug_do(
159                storage = memalign( __page_size, size + __page_size );
160        );
161        __cfaabi_dbg_no_debug_do(
162                storage = (void*)malloc(size);
163        );
164
165        __cfaabi_dbg_print_safe("Kernel : Created stack %p of size %zu\n", storage, size);
166        __cfaabi_dbg_debug_do(
167                if ( mprotect( storage, __page_size, PROT_NONE ) == -1 ) {
168                        abort( "__stack_alloc : internal error, mprotect failure, error(%d) %s.", (int)errno, strerror( (int)errno ) );
169                }
170                storage = (void *)(((intptr_t)storage) + __page_size);
171        );
172
173        verify( ((intptr_t)storage & (libAlign() - 1)) == 0ul );
174        return [storage, size];
175}
176
177void __stack_prepare( __stack_info_t * this, size_t create_size ) {
178        static const size_t stack_data_size = libCeiling( sizeof(__stack_t), 16 ); // minimum alignment
179        bool userStack;
180        void * storage;
181        size_t size;
182        if ( !this->storage ) {
183                userStack = false;
184                [storage, size] = __stack_alloc( create_size );
185        } else {
186                userStack = true;
187                __cfaabi_dbg_print_safe("Kernel : stack obj %p using user stack %p(%zu bytes)\n", this, this->storage, this->storage->size);
188
189                // The stack must be aligned, advance the pointer to the next align data
190                storage = (void*)libCeiling( (intptr_t)this->storage, libAlign());
191
192                // The size needs to be shrinked to fit all the extra data structure and be aligned
193                ptrdiff_t diff = (intptr_t)storage - (intptr_t)this->storage;
194                size = libFloor(create_size - stack_data_size - diff, libAlign());
195        } // if
196        assertf( size >= MinStackSize, "Stack size %zd provides less than minimum of %d bytes for a stack.", size, MinStackSize );
197
198        this->storage = (__stack_t *)((intptr_t)storage + size);
199        this->storage->size  = size;
200        this->storage->limit = storage;
201        this->storage->base  = (void*)((intptr_t)storage + size);
202        this->userStack = userStack;
203}
204
205// We need to call suspend from invoke.c, so we expose this wrapper that
206// is not inline (We can't inline Cforall in C)
207extern "C" {
208        void __suspend_internal(void) {
209                suspend();
210        }
211
212        void __leave_coroutine( coroutine_desc * src ) {
213                coroutine_desc * starter = src->cancellation != 0 ? src->last : src->starter;
214
215                src->state = Halted;
216
217                assertf( starter != 0,
218                        "Attempt to suspend/leave coroutine \"%.256s\" (%p) that has never been resumed.\n"
219                        "Possible cause is a suspend executed in a member called by a coroutine user rather than by the coroutine main.",
220                        src->name, src );
221                assertf( starter->state != Halted,
222                        "Attempt by coroutine \"%.256s\" (%p) to suspend/leave back to terminated coroutine \"%.256s\" (%p).\n"
223                        "Possible cause is terminated coroutine's main routine has already returned.",
224                        src->name, src, starter->name, starter );
225
226                CoroutineCtxSwitch( src, starter );
227        }
228}
229
230// Local Variables: //
231// mode: c //
232// tab-width: 4 //
233// End: //
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