1 /* 2 * Copyright (c) 2008-2010 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Matthew Dillon <dillon@backplane.com> 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 /* 35 * Provides the vkernel with an asynchronous I/O mechanism using pthreads 36 * which operates outside the cpu abstraction. Cothreads are intended to 37 * operate like DMA engines and may ONLY make libc and cothread_*() calls. 38 * The cothread may NOT call into the vkernel since abstractions like 39 * 'mycpu' do not exist for it. 40 */ 41 42 #include <sys/types.h> 43 #include <sys/interrupt.h> 44 #include <sys/kernel.h> 45 #include <sys/malloc.h> 46 #include <sys/memrange.h> 47 #include <sys/tls.h> 48 #include <sys/bus.h> 49 #include <sys/thread2.h> 50 #include <time.h> 51 52 #include <vm/vm_extern.h> 53 #include <vm/vm_kern.h> 54 #include <vm/vm_object.h> 55 #include <vm/vm_page.h> 56 57 #include <machine/cpu.h> 58 #include <machine/cpufunc.h> 59 #include <machine/globaldata.h> 60 #include <machine/md_var.h> 61 #include <machine/pmap.h> 62 #include <machine/smp.h> 63 #include <machine/tls.h> 64 #include <machine/cothread.h> 65 66 #include <unistd.h> 67 #include <pthread.h> 68 #include <signal.h> 69 #include <stdio.h> 70 71 static void cothread_thread(void *arg); 72 73 /* 74 * Create a co-processor thread for a virtual kernel. This thread operates 75 * outside of the virtual kernel cpu abstraction and may only make direct 76 * cothread and libc calls. 77 */ 78 cothread_t 79 cothread_create(void (*thr_func)(cothread_t cotd), 80 void (*thr_intr)(cothread_t cotd), 81 void *arg, const char *name) 82 { 83 cothread_t cotd; 84 pthread_attr_t attr; 85 86 cotd = kmalloc(sizeof(*cotd), M_DEVBUF, M_WAITOK|M_ZERO); 87 cotd->thr_intr = thr_intr; 88 cotd->thr_func = thr_func; 89 cotd->arg = arg; 90 crit_enter(); 91 pthread_mutex_init(&cotd->mutex, NULL); 92 pthread_cond_init(&cotd->cond, NULL); 93 crit_exit(); 94 95 cotd->pintr = pthread_self(); 96 97 if (thr_intr) { 98 cotd->intr_id = register_int_virtual(1, (void *)thr_intr, 99 cotd, name, 100 NULL, INTR_MPSAFE); 101 } 102 103 /* 104 * The vkernel's cpu_disable_intr() masks signals. We don't want 105 * our coprocessor thread taking any unix signals :-) 106 */ 107 pthread_attr_init(&attr); 108 crit_enter(); 109 cpu_mask_all_signals(); 110 pthread_create(&cotd->pthr, &attr, (void *)cothread_thread, cotd); 111 cpu_unmask_all_signals(); 112 crit_exit(); 113 pthread_attr_destroy(&attr); 114 115 return(cotd); 116 } 117 118 /* 119 * Wait for the target thread to terminate and then destroy the cothread 120 * structure. 121 */ 122 void 123 cothread_delete(cothread_t *cotdp) 124 { 125 cothread_t cotd; 126 127 if ((cotd = *cotdp) != NULL) { 128 if (cotd->thr_intr) 129 unregister_int_virtual(cotd->intr_id); 130 crit_enter(); 131 pthread_join(cotd->pthr, NULL); 132 crit_exit(); 133 kfree(cotd, M_DEVBUF); 134 *cotdp = NULL; 135 } 136 } 137 138 static void 139 cothread_thread(void *arg) 140 { 141 cothread_t cotd = arg; 142 143 cpu_mask_all_signals(); /* XXX remove me? should already be masked */ 144 /* 145 * %gs (aka mycpu) is illegal in cothreads. Note that %fs is used 146 * by pthreads. 147 */ 148 /* JG try another approach? */ 149 tls_set_gs(0, sizeof(struct privatespace)); 150 cotd->thr_func(cotd); 151 } 152 153 /* 154 * Called by the cothread to generate an interrupt back to the vkernel. 155 */ 156 void 157 cothread_intr(cothread_t cotd) 158 { 159 pthread_kill(cotd->pintr, SIGALRM); 160 } 161 162 /* 163 * Called by the vkernel to wakeup a cothread. 164 * The cothread must be locked. 165 */ 166 void 167 cothread_signal(cothread_t cotd) 168 { 169 pthread_cond_signal(&cotd->cond); 170 } 171 172 /* 173 * Called by the cothread to wait for the vkernel to call cothread_signal(). 174 * The cothread must be locked. 175 */ 176 void 177 cothread_wait(cothread_t cotd) 178 { 179 pthread_cond_wait(&cotd->cond, &cotd->mutex); 180 } 181 182 /* 183 * Used for systimer support 184 */ 185 void 186 cothread_sleep(cothread_t cotd, struct timespec *ts) 187 { 188 nanosleep(ts, NULL); 189 } 190 191 void 192 cothread_wakeup(cothread_t cotd, struct timespec *ts) 193 { 194 ts->tv_sec = 0; 195 ts->tv_nsec = 0; 196 pthread_kill(cotd->pthr, SIGINT); 197 } 198 199 /* 200 * Typically called by kernel thread or cothread 201 * 202 * These must be a matched pair. We will acquire a critical 203 * section in cothread_lock() and release it in cothread_unlock(). 204 * 205 * We do this to simplify cothread operation to prevent an 206 * interrupt (e.g. vkd_io_intr()) from preempting a vkd_strategy() 207 * call and creating a recursion in the pthread. 208 */ 209 void 210 cothread_lock(cothread_t cotd, int is_cotd) 211 { 212 if (is_cotd) { 213 pthread_mutex_lock(&cotd->mutex); 214 } else { 215 crit_enter_id("cothread"); 216 pthread_mutex_lock(&cotd->mutex); 217 } 218 } 219 220 void 221 cothread_unlock(cothread_t cotd, int is_cotd) 222 { 223 if (is_cotd) { 224 pthread_mutex_unlock(&cotd->mutex); 225 } else { 226 pthread_mutex_unlock(&cotd->mutex); 227 crit_exit_id("cothread"); 228 } 229 } 230