/* * Copyright (c) 2008-2010 The DragonFly Project. All rights reserved. * * This code is derived from software contributed to The DragonFly Project * by Matthew Dillon <dillon@backplane.com> * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3. Neither the name of The DragonFly Project nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific, prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* * Provides the vkernel with an asynchronous I/O mechanism using pthreads * which operates outside the cpu abstraction. Cothreads are intended to * operate like DMA engines and may ONLY make libc and cothread_*() calls. * The cothread may NOT call into the vkernel since abstractions like * 'mycpu' do not exist for it. */ #include <sys/types.h> #include <sys/interrupt.h> #include <sys/kernel.h> #include <sys/malloc.h> #include <sys/memrange.h> #include <sys/tls.h> #include <sys/bus.h> #include <sys/thread2.h> #include <time.h> #include <vm/vm_extern.h> #include <vm/vm_kern.h> #include <vm/vm_object.h> #include <vm/vm_page.h> #include <machine/cpu.h> #include <machine/cpufunc.h> #include <machine/globaldata.h> #include <machine/md_var.h> #include <machine/pmap.h> #include <machine/smp.h> #include <machine/tls.h> #include <machine/cothread.h> #include <unistd.h> #include <pthread.h> #include <signal.h> #include <stdio.h> static void cothread_thread(void *arg); /* * Create a co-processor thread for a virtual kernel. This thread operates * outside of the virtual kernel cpu abstraction and may only make direct * cothread and libc calls. */ cothread_t cothread_create(void (*thr_func)(cothread_t cotd), void (*thr_intr)(cothread_t cotd), void *arg, const char *name) { cothread_t cotd; pthread_attr_t attr; cotd = kmalloc(sizeof(*cotd), M_DEVBUF, M_WAITOK|M_ZERO); cotd->thr_intr = thr_intr; cotd->thr_func = thr_func; cotd->arg = arg; crit_enter(); pthread_mutex_init(&cotd->mutex, NULL); pthread_cond_init(&cotd->cond, NULL); crit_exit(); cotd->pintr = pthread_self(); if (thr_intr) { cotd->intr_id = register_int_virtual(1, (void *)thr_intr, cotd, name, NULL, INTR_MPSAFE); } /* * The vkernel's cpu_disable_intr() masks signals. We don't want * our coprocessor thread taking any unix signals :-) */ pthread_attr_init(&attr); crit_enter(); cpu_mask_all_signals(); pthread_create(&cotd->pthr, &attr, (void *)cothread_thread, cotd); cpu_unmask_all_signals(); crit_exit(); pthread_attr_destroy(&attr); return(cotd); } /* * Wait for the target thread to terminate and then destroy the cothread * structure. */ void cothread_delete(cothread_t *cotdp) { cothread_t cotd; if ((cotd = *cotdp) != NULL) { if (cotd->thr_intr) unregister_int_virtual(cotd->intr_id); crit_enter(); pthread_join(cotd->pthr, NULL); crit_exit(); kfree(cotd, M_DEVBUF); *cotdp = NULL; } } static void cothread_thread(void *arg) { cothread_t cotd = arg; cpu_mask_all_signals(); /* XXX remove me? should already be masked */ /* * %gs (aka mycpu) is illegal in cothreads. Note that %fs is used * by pthreads. */ /* JG try another approach? */ tls_set_gs(0, sizeof(struct privatespace)); cotd->thr_func(cotd); } /* * Called by the cothread to generate an interrupt back to the vkernel. */ void cothread_intr(cothread_t cotd) { pthread_kill(cotd->pintr, SIGALRM); } /* * Called by the vkernel to wakeup a cothread. * The cothread must be locked. */ void cothread_signal(cothread_t cotd) { pthread_cond_signal(&cotd->cond); } /* * Called by the cothread to wait for the vkernel to call cothread_signal(). * The cothread must be locked. */ void cothread_wait(cothread_t cotd) { pthread_cond_wait(&cotd->cond, &cotd->mutex); } /* * Used for systimer support */ void cothread_sleep(cothread_t cotd, struct timespec *ts) { nanosleep(ts, NULL); } void cothread_wakeup(cothread_t cotd, struct timespec *ts) { ts->tv_sec = 0; ts->tv_nsec = 0; pthread_kill(cotd->pthr, SIGINT); } /* * Typically called by kernel thread or cothread * * These must be a matched pair. We will acquire a critical * section in cothread_lock() and release it in cothread_unlock(). * * We do this to simplify cothread operation to prevent an * interrupt (e.g. vkd_io_intr()) from preempting a vkd_strategy() * call and creating a recursion in the pthread. */ void cothread_lock(cothread_t cotd, int is_cotd) { if (is_cotd) { pthread_mutex_lock(&cotd->mutex); } else { crit_enter_id("cothread"); pthread_mutex_lock(&cotd->mutex); } } void cothread_unlock(cothread_t cotd, int is_cotd) { if (is_cotd) { pthread_mutex_unlock(&cotd->mutex); } else { pthread_mutex_unlock(&cotd->mutex); crit_exit_id("cothread"); } }
