Ignore:
Timestamp:
Apr 4, 2019, 3:37:55 PM (3 years ago)
Author:
tdelisle <tdelisle@…>
Branches:
arm-eh, cleanup-dtors, jacob/cs343-translation, jenkins-sandbox, master, new-ast, new-ast-unique-expr
Children:
8c01e1b
Parents:
2fabdc02
Message:

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

File:
1 edited

Legend:

Unmodified
Added
Removed
  • libcfa/src/concurrency/coroutine.cfa

    r2fabdc02 rb2f6113  
    3535
    3636extern "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       }
     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        }
    4242}
    4343
     
    4747// minimum feasible stack size in bytes
    4848#define MinStackSize 1000
    49 static size_t pageSize = 0;                             // architecture pagesize HACK, should go in proper runtime singleton
     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 );
    5052
    5153//-----------------------------------------------------------------------------
    5254// Coroutine ctors and dtors
    53 void ?{}( coStack_t & this, void * storage, size_t storageSize ) with( this ) {
    54       size               = storageSize == 0 ? 65000 : storageSize; // size of stack
    55       this.storage = storage;                                // pointer to stack
    56       limit              = NULL;                                   // stack grows towards stack limit
    57       base               = NULL;                                   // base of stack
    58       context    = NULL;                                   // address of cfa_context_t
    59       top                = NULL;                                   // address of top of storage
    60       userStack  = storage != NULL;
    61 }
    62 
    63 void ^?{}(coStack_t & this) {
    64       if ( ! this.userStack && this.storage ) {
    65             __cfaabi_dbg_debug_do(
    66                   if ( mprotect( this.storage, pageSize, PROT_READ | PROT_WRITE ) == -1 ) {
    67                         abort( "(coStack_t *)%p.^?{}() : internal error, mprotect failure, error(%d) %s.", &this, errno, strerror( errno ) );
    68                   }
    69             );
    70             free( this.storage );
    71       }
     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        }
    7281}
    7382
    7483void ?{}( coroutine_desc & this, const char * name, void * storage, size_t storageSize ) with( this ) {
    75       (this.stack){storage, storageSize};
    76       this.name = name;
    77       errno_ = 0;
    78       state = Start;
    79       starter = NULL;
    80       last = NULL;
    81       cancellation = NULL;
     84        (this.stack){storage, storageSize};
     85        this.name = name;
     86        state = Start;
     87        starter = NULL;
     88        last = NULL;
     89        cancellation = NULL;
    8290}
    8391
    8492void ^?{}(coroutine_desc& this) {
    85       if(this.state != Halted && this.state != Start) {
    86             coroutine_desc * src = TL_GET( this_thread )->curr_cor;
    87             coroutine_desc * dst = &this;
    88 
    89             struct _Unwind_Exception storage;
    90             storage.exception_class = -1;
    91             storage.exception_cleanup = _CtxCoroutine_UnwindCleanup;
    92             this.cancellation = &storage;
    93             this.last = src;
    94 
    95               // not resuming self ?
    96               if ( src == dst ) {
    97                       abort( "Attempt by coroutine %.256s (%p) to terminate itself.\n", src->name, src );
    98             }
    99 
    100               CoroutineCtxSwitch( src, dst );
    101       }
     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        }
    102110}
    103111
     
    106114forall(dtype T | is_coroutine(T))
    107115void prime(T& cor) {
    108       coroutine_desc* this = get_coroutine(cor);
    109       assert(this->state == Start);
    110 
    111       this->state = Primed;
    112       resume(cor);
     116        coroutine_desc* this = get_coroutine(cor);
     117        assert(this->state == Start);
     118
     119        this->state = Primed;
     120        resume(cor);
    113121}
    114122
    115123// Wrapper for co
    116124void CoroutineCtxSwitch(coroutine_desc* src, coroutine_desc* dst) {
    117       // Safety note : Preemption must be disabled since there is a race condition
    118       // kernelTLS.this_thread->curr_cor and $rsp/$rbp must agree at all times
    119       verify( TL_GET( preemption_state.enabled ) || TL_GET( this_processor )->do_terminate );
    120       disable_interrupts();
    121 
    122       // set state of current coroutine to inactive
    123       src->state = src->state == Halted ? Halted : Inactive;
    124 
    125       // set new coroutine that task is executing
    126       TL_GET( this_thread )->curr_cor = dst;
    127 
    128       // context switch to specified coroutine
    129       assert( src->stack.context );
    130       CtxSwitch( src->stack.context, dst->stack.context );
    131       // when CtxSwitch returns we are back in the src coroutine
    132 
    133       // set state of new coroutine to active
    134       src->state = Active;
    135 
    136       enable_interrupts( __cfaabi_dbg_ctx );
    137       verify( TL_GET( preemption_state.enabled ) || TL_GET( this_processor )->do_terminate );
    138 
    139 
    140       if( unlikely(src->cancellation != NULL) ) {
    141             _CtxCoroutine_Unwind(src->cancellation, src);
    142       }
    143 } //ctxSwitchDirect
    144 
    145 void create_stack( coStack_t* this, unsigned int storageSize ) with( *this ) {
    146       //TEMP HACK do this on proper kernel startup
    147       if(pageSize == 0ul) pageSize = sysconf( _SC_PAGESIZE );
    148 
    149       size_t cxtSize = libCeiling( sizeof(machine_context_t), 8 ); // minimum alignment
    150 
    151       if ( !storage ) {
    152             __cfaabi_dbg_print_safe("Kernel : Creating stack of size %zu for stack obj %p\n", cxtSize + size + 8, this);
    153 
    154             userStack = false;
    155             size = libCeiling( storageSize, 16 );
    156             // use malloc/memalign because "new" raises an exception for out-of-memory
    157 
    158             // assume malloc has 8 byte alignment so add 8 to allow rounding up to 16 byte alignment
    159             __cfaabi_dbg_debug_do( storage = memalign( pageSize, cxtSize + size + pageSize ) );
    160             __cfaabi_dbg_no_debug_do( storage = malloc( cxtSize + size + 8 ) );
    161 
    162             __cfaabi_dbg_debug_do(
    163                   if ( mprotect( storage, pageSize, PROT_NONE ) == -1 ) {
    164                         abort( "(uMachContext &)%p.createContext() : internal error, mprotect failure, error(%d) %s.", this, (int)errno, strerror( (int)errno ) );
    165                   } // if
    166             );
    167 
    168             if ( (intptr_t)storage == 0 ) {
    169                   abort( "Attempt to allocate %zd bytes of storage for coroutine or task execution-state but insufficient memory available.", size );
    170             } // if
    171 
    172             __cfaabi_dbg_debug_do( limit = (char *)storage + pageSize );
    173             __cfaabi_dbg_no_debug_do( limit = (char *)libCeiling( (unsigned long)storage, 16 ) ); // minimum alignment
    174 
    175       } else {
    176             __cfaabi_dbg_print_safe("Kernel : stack obj %p using user stack %p(%u bytes)\n", this, storage, storageSize);
    177 
    178             assertf( ((size_t)storage & (libAlign() - 1)) == 0ul, "Stack storage %p for task/coroutine must be aligned on %d byte boundary.", storage, (int)libAlign() );
    179             userStack = true;
    180             size = storageSize - cxtSize;
    181 
    182             if ( size % 16 != 0u ) size -= 8;
    183 
    184             limit = (char *)libCeiling( (unsigned long)storage, 16 ); // minimum alignment
    185       } // if
    186       assertf( size >= MinStackSize, "Stack size %zd provides less than minimum of %d bytes for a stack.", size, MinStackSize );
    187 
    188       base = (char *)limit + size;
    189       context = base;
    190       top = (char *)context + cxtSize;
     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;
    191203}
    192204
     
    194206// is not inline (We can't inline Cforall in C)
    195207extern "C" {
    196       void __suspend_internal(void) {
    197             suspend();
    198       }
    199 
    200       void __leave_coroutine( coroutine_desc * src ) {
    201             coroutine_desc * starter = src->cancellation != 0 ? src->last : src->starter;
    202 
    203             src->state = Halted;
    204 
    205             assertf( starter != 0,
    206                   "Attempt to suspend/leave coroutine \"%.256s\" (%p) that has never been resumed.\n"
    207                   "Possible cause is a suspend executed in a member called by a coroutine user rather than by the coroutine main.",
    208                   src->name, src );
    209             assertf( starter->state != Halted,
    210                   "Attempt by coroutine \"%.256s\" (%p) to suspend/leave back to terminated coroutine \"%.256s\" (%p).\n"
    211                   "Possible cause is terminated coroutine's main routine has already returned.",
    212                   src->name, src, starter->name, starter );
    213 
    214             CoroutineCtxSwitch( src, starter );
    215       }
     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        }
    216228}
    217229
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