2017-01-24 13:45:56 +01:00
|
|
|
/* fibers.c -- extremely simple lightweight thread (fiber) implementation
|
2018-01-03 11:03:58 +01:00
|
|
|
Copyright (C) 2016-2018 Free Software Foundation, Inc.
|
2017-01-24 13:45:56 +01:00
|
|
|
Contributed by Pekka Jaaskelainen <pekka.jaaskelainen@parmance.com>
|
|
|
|
for General Processor Tech.
|
|
|
|
|
2018-01-03 11:03:58 +01:00
|
|
|
Copyright (C) 2015-2018 Free Software Foundation, Inc.
|
2017-01-24 13:45:56 +01:00
|
|
|
Contributed by Pekka Jaaskelainen <pekka.jaaskelainen@parmance.com>
|
|
|
|
for General Processor Tech.
|
|
|
|
|
|
|
|
Permission is hereby granted, free of charge, to any person obtaining a
|
|
|
|
copy of this software and associated documentation files
|
|
|
|
(the "Software"), to deal in the Software without restriction, including
|
|
|
|
without limitation the rights to use, copy, modify, merge, publish,
|
|
|
|
distribute, sublicense, and/or sell copies of the Software, and to
|
|
|
|
permit persons to whom the Software is furnished to do so, subject to
|
|
|
|
the following conditions:
|
|
|
|
|
|
|
|
The above copyright notice and this permission notice shall be included
|
|
|
|
in all copies or substantial portions of the Software.
|
|
|
|
|
|
|
|
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
|
|
|
|
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
|
|
|
|
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
|
|
|
|
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
|
|
|
|
DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
|
|
|
|
OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
|
|
|
|
USE OR OTHER DEALINGS IN THE SOFTWARE.
|
|
|
|
*/
|
|
|
|
|
|
|
|
#include <stdlib.h>
|
|
|
|
#include <stdio.h>
|
|
|
|
#include <stdint.h>
|
|
|
|
|
|
|
|
#include "target-config.h"
|
|
|
|
|
|
|
|
#include "fibers.h"
|
|
|
|
|
|
|
|
void
|
|
|
|
phsa_fatal_error (int code);
|
|
|
|
|
|
|
|
ucontext_t main_context;
|
|
|
|
|
|
|
|
/* The last fiber in the linked list. */
|
|
|
|
static fiber_t *tail_fiber = NULL;
|
|
|
|
/* The first fiber in the linked list. */
|
|
|
|
static fiber_t *head_fiber = NULL;
|
|
|
|
/* The fiber currently being executed. */
|
|
|
|
static fiber_t *current_fiber = NULL;
|
|
|
|
|
|
|
|
/* Makecontext accepts only integer arguments. We need to split the
|
|
|
|
pointer argument in case pointer does not fit into int. This helper
|
|
|
|
function can be used to restore the pointer from the arguments. */
|
|
|
|
|
|
|
|
void *
|
|
|
|
fiber_int_args_to_ptr (int arg0, int arg1)
|
|
|
|
{
|
|
|
|
void *ptr = NULL;
|
|
|
|
#if SIZEOF_VOIDP == 8 && SIZEOF_INT == 4
|
|
|
|
ptr = (void*)(((uint64_t) arg0 & (uint64_t) 0xFFFFFFFF)
|
|
|
|
| ((uint64_t) arg1 << 32));
|
|
|
|
#elif SIZEOF_VOIDP == 4 && SIZEOF_INT == 4
|
|
|
|
ptr = (void*)arg0;
|
|
|
|
#else
|
|
|
|
# error Unsupported pointer/int size.
|
|
|
|
#endif
|
|
|
|
return ptr;
|
|
|
|
}
|
|
|
|
|
|
|
|
void
|
|
|
|
fiber_init (fiber_t *fiber, fiber_function_t start_function, void *arg,
|
|
|
|
size_t stack_size, size_t stack_align)
|
|
|
|
{
|
|
|
|
int arg0, arg1;
|
|
|
|
if (getcontext (&fiber->context) != 0)
|
|
|
|
phsa_fatal_error (3);
|
|
|
|
if (posix_memalign (&fiber->context.uc_stack.ss_sp, stack_align, stack_size)
|
|
|
|
!= 0)
|
|
|
|
phsa_fatal_error (4);
|
|
|
|
fiber->context.uc_stack.ss_size = stack_size;
|
|
|
|
fiber->context.uc_link = &main_context;
|
|
|
|
|
|
|
|
/* makecontext () accepts only integer arguments. Split the
|
|
|
|
pointer argument to two args in the case pointer does not fit
|
|
|
|
into one int. */
|
|
|
|
#if SIZEOF_VOIDP == 8 && SIZEOF_INT == 4
|
|
|
|
arg0 = (int32_t) 0xFFFFFFFF & (uint64_t)arg;
|
|
|
|
arg1 = (int32_t) 0xFFFFFFFF & ((uint64_t)arg >> 32);
|
|
|
|
#elif SIZEOF_VOIDP == 4 && SIZEOF_INT == 4
|
|
|
|
arg0 = (int)arg;
|
|
|
|
arg1 = 0;
|
|
|
|
#else
|
|
|
|
# error Unsupported pointer/int size.
|
|
|
|
#endif
|
|
|
|
|
|
|
|
makecontext (&fiber->context, (void*)start_function, 2, arg0, arg1);
|
|
|
|
|
|
|
|
fiber->status = FIBER_STATUS_READY;
|
|
|
|
fiber->next = NULL;
|
|
|
|
fiber->prev = NULL;
|
|
|
|
|
|
|
|
/* Create a linked list of the created fibers. Append the new one at
|
|
|
|
the end. */
|
|
|
|
if (tail_fiber == NULL)
|
|
|
|
tail_fiber = fiber;
|
|
|
|
else
|
|
|
|
{
|
|
|
|
tail_fiber->next = fiber;
|
|
|
|
fiber->prev = tail_fiber;
|
|
|
|
tail_fiber = fiber;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (head_fiber == NULL)
|
|
|
|
head_fiber = fiber;
|
|
|
|
}
|
|
|
|
|
|
|
|
void
|
|
|
|
fiber_exit ()
|
|
|
|
{
|
|
|
|
fiber_status_t old_status = current_fiber->status;
|
|
|
|
current_fiber->status = FIBER_STATUS_EXITED;
|
|
|
|
if (old_status == FIBER_STATUS_JOINED)
|
|
|
|
/* In case this thread has been joined, return back to the joiner. */
|
|
|
|
swapcontext (¤t_fiber->context, &main_context);
|
|
|
|
else
|
|
|
|
/* In case the thread exited while being yielded from another thread,
|
|
|
|
switch back to another fiber. */
|
|
|
|
fiber_yield ();
|
|
|
|
}
|
|
|
|
|
|
|
|
void
|
|
|
|
fiber_join (fiber_t *fiber)
|
|
|
|
{
|
|
|
|
fiber_t *next_ready_fiber = NULL;
|
|
|
|
current_fiber = fiber;
|
|
|
|
if (fiber->status != FIBER_STATUS_EXITED)
|
|
|
|
{
|
|
|
|
fiber->status = FIBER_STATUS_JOINED;
|
|
|
|
while (fiber->status != FIBER_STATUS_EXITED)
|
|
|
|
swapcontext (&main_context, &fiber->context);
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Remove the successfully joined fiber from the linked list so we won't
|
|
|
|
access it later (the fiber itself might be freed after the join). */
|
|
|
|
if (fiber->prev != NULL)
|
|
|
|
fiber->prev->next = fiber->next;
|
|
|
|
|
|
|
|
if (fiber->next != NULL)
|
|
|
|
fiber->next->prev = fiber->prev;
|
|
|
|
|
|
|
|
if (head_fiber == fiber)
|
|
|
|
head_fiber = fiber->next;
|
|
|
|
|
|
|
|
if (tail_fiber == fiber)
|
|
|
|
tail_fiber = fiber->prev;
|
|
|
|
|
|
|
|
free (fiber->context.uc_stack.ss_sp);
|
|
|
|
}
|
|
|
|
|
|
|
|
void
|
|
|
|
fiber_yield ()
|
|
|
|
{
|
|
|
|
fiber_t *next_ready_fiber = current_fiber;
|
|
|
|
|
|
|
|
if (current_fiber == head_fiber
|
|
|
|
&& current_fiber == tail_fiber)
|
|
|
|
{
|
|
|
|
/* If the last fiber exits independently, there is no
|
|
|
|
fiber to switch to. Switch to the main context in that
|
|
|
|
case. */
|
|
|
|
if (current_fiber->status == FIBER_STATUS_EXITED)
|
|
|
|
swapcontext (¤t_fiber->context, &main_context);
|
|
|
|
}
|
|
|
|
|
|
|
|
do {
|
|
|
|
next_ready_fiber = next_ready_fiber->next != NULL
|
|
|
|
? next_ready_fiber->next : head_fiber;
|
|
|
|
} while (next_ready_fiber != current_fiber
|
|
|
|
&& next_ready_fiber->status == FIBER_STATUS_EXITED);
|
|
|
|
|
|
|
|
fiber_t *old_current_fiber = current_fiber;
|
|
|
|
current_fiber = next_ready_fiber;
|
|
|
|
swapcontext (&old_current_fiber->context, &next_ready_fiber->context);
|
|
|
|
}
|
|
|
|
|
|
|
|
size_t
|
|
|
|
fiber_barrier_reach (fiber_barrier_t *barrier)
|
|
|
|
{
|
|
|
|
/* Yield once to ensure that there are no fibers waiting for
|
|
|
|
a previous triggering of the barrier in the waiting_count
|
|
|
|
loop. This should release them before we update the reached
|
|
|
|
counter again. */
|
|
|
|
fiber_yield ();
|
|
|
|
|
|
|
|
barrier->reached++;
|
|
|
|
++barrier->waiting_count;
|
|
|
|
while (barrier->reached < barrier->threshold)
|
|
|
|
fiber_yield ();
|
|
|
|
--barrier->waiting_count;
|
|
|
|
|
|
|
|
/* Wait until all the fibers have reached this point. */
|
|
|
|
while (barrier->waiting_count > 0)
|
|
|
|
fiber_yield ();
|
|
|
|
|
|
|
|
/* Now all fibers have been released from the barrier waiting
|
|
|
|
loop. We can now safely reset the reach count for new triggering. */
|
|
|
|
if (barrier->reached > 0)
|
|
|
|
{
|
|
|
|
barrier->reached = 0;
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
|
|
|
|
void
|
|
|
|
fiber_barrier_init (fiber_barrier_t *barrier, size_t threshold)
|
|
|
|
{
|
|
|
|
barrier->threshold = threshold;
|
|
|
|
barrier->waiting_count = 0;
|
|
|
|
barrier->reached = 0;
|
|
|
|
}
|