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/interrupt.h> 43 #include <sys/kernel.h> 44 #include <sys/memrange.h> 45 #include <sys/tls.h> 46 #include <sys/types.h> 47 #include <sys/bus.h> 48 #include <sys/thread2.h> 49 #include <time.h> 50 51 #include <vm/vm_extern.h> 52 #include <vm/vm_kern.h> 53 #include <vm/vm_object.h> 54 #include <vm/vm_page.h> 55 56 #include <machine/cpu.h> 57 #include <machine/cpufunc.h> 58 #include <machine/globaldata.h> 59 #include <machine/md_var.h> 60 #include <machine/pmap.h> 61 #include <machine/smp.h> 62 #include <machine/tls.h> 63 #include <machine/cothread.h> 64 65 #include <unistd.h> 66 #include <pthread.h> 67 #include <signal.h> 68 #include <stdio.h> 69 70 static void cothread_thread(void *arg); 71 extern int vmm_enabled; 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 void *stack; 85 pthread_attr_t attr; 86 87 cotd = kmalloc(sizeof(*cotd), M_DEVBUF, M_WAITOK|M_ZERO); 88 cotd->thr_intr = thr_intr; 89 cotd->thr_func = thr_func; 90 cotd->arg = arg; 91 crit_enter(); 92 pthread_mutex_init(&cotd->mutex, NULL); 93 pthread_cond_init(&cotd->cond, NULL); 94 crit_exit(); 95 96 cotd->pintr = pthread_self(); 97 98 if (thr_intr) { 99 cotd->intr_id = register_int_virtual(1, (void *)thr_intr, 100 cotd, name, 101 NULL, INTR_MPSAFE); 102 } 103 104 /* 105 * The vkernel's cpu_disable_intr() masks signals. We don't want 106 * our coprocessor thread taking any unix signals :-) 107 */ 108 pthread_attr_init(&attr); 109 if (vmm_enabled) { 110 stack = mmap(NULL, KERNEL_STACK_SIZE, 111 PROT_READ|PROT_WRITE|PROT_EXEC, 112 MAP_ANON, -1, 0); 113 if (stack == MAP_FAILED) { 114 panic("Unable to allocate stack for cothread\n"); 115 } 116 pthread_attr_setstack(&attr, stack, KERNEL_STACK_SIZE); 117 } 118 crit_enter(); 119 cpu_mask_all_signals(); 120 pthread_create(&cotd->pthr, &attr, (void *)cothread_thread, cotd); 121 cpu_unmask_all_signals(); 122 crit_exit(); 123 pthread_attr_destroy(&attr); 124 125 return(cotd); 126 } 127 128 /* 129 * Wait for the target thread to terminate and then destroy the cothread 130 * structure. 131 */ 132 void 133 cothread_delete(cothread_t *cotdp) 134 { 135 cothread_t cotd; 136 137 if ((cotd = *cotdp) != NULL) { 138 if (cotd->thr_intr) 139 unregister_int_virtual(cotd->intr_id); 140 crit_enter(); 141 pthread_join(cotd->pthr, NULL); 142 crit_exit(); 143 kfree(cotd, M_DEVBUF); 144 *cotdp = NULL; 145 } 146 } 147 148 static void 149 cothread_thread(void *arg) 150 { 151 cothread_t cotd = arg; 152 153 cpu_mask_all_signals(); /* XXX remove me? should already be masked */ 154 /* 155 * %gs (aka mycpu) is illegal in cothreads. Note that %fs is used 156 * by pthreads. 157 */ 158 /* JG try another approach? */ 159 tls_set_gs(0, sizeof(struct privatespace)); 160 cotd->thr_func(cotd); 161 } 162 163 /* 164 * Called by the cothread to generate an interrupt back to the vkernel. 165 */ 166 void 167 cothread_intr(cothread_t cotd) 168 { 169 pthread_kill(cotd->pintr, SIGALRM); 170 } 171 172 /* 173 * Called by the vkernel to wakeup a cothread. 174 * The cothread must be locked. 175 */ 176 void 177 cothread_signal(cothread_t cotd) 178 { 179 pthread_cond_signal(&cotd->cond); 180 } 181 182 /* 183 * Called by the cothread to wait for the vkernel to call cothread_signal(). 184 * The cothread must be locked. 185 */ 186 void 187 cothread_wait(cothread_t cotd) 188 { 189 pthread_cond_wait(&cotd->cond, &cotd->mutex); 190 } 191 192 /* 193 * Used for systimer support 194 */ 195 void 196 cothread_sleep(cothread_t cotd, struct timespec *ts) 197 { 198 nanosleep(ts, NULL); 199 } 200 201 void 202 cothread_wakeup(cothread_t cotd, struct timespec *ts) 203 { 204 ts->tv_sec = 0; 205 ts->tv_nsec = 0; 206 pthread_kill(cotd->pthr, SIGINT); 207 } 208 209 /* 210 * Typically called by kernel thread or cothread 211 * 212 * These must be a matched pair. We will acquire a critical 213 * section in cothread_lock() and release it in cothread_unlock(). 214 * 215 * We do this to simplify cothread operation to prevent an 216 * interrupt (e.g. vkd_io_intr()) from preempting a vkd_strategy() 217 * call and creating a recursion in the pthread. 218 */ 219 void 220 cothread_lock(cothread_t cotd, int is_cotd) 221 { 222 if (is_cotd) { 223 pthread_mutex_lock(&cotd->mutex); 224 } else { 225 crit_enter_id("cothread"); 226 pthread_mutex_lock(&cotd->mutex); 227 } 228 } 229 230 void 231 cothread_unlock(cothread_t cotd, int is_cotd) 232 { 233 if (is_cotd) { 234 pthread_mutex_unlock(&cotd->mutex); 235 } else { 236 pthread_mutex_unlock(&cotd->mutex); 237 crit_exit_id("cothread"); 238 } 239 } 240