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 extern int vmm_enabled; 73 74 /* 75 * Create a co-processor thread for a virtual kernel. This thread operates 76 * outside of the virtual kernel cpu abstraction and may only make direct 77 * cothread and libc calls. 78 */ 79 cothread_t 80 cothread_create(void (*thr_func)(cothread_t cotd), 81 void (*thr_intr)(cothread_t cotd), 82 void *arg, const char *name) 83 { 84 cothread_t cotd; 85 void *stack; 86 pthread_attr_t attr; 87 88 cotd = kmalloc(sizeof(*cotd), M_DEVBUF, M_WAITOK|M_ZERO); 89 cotd->thr_intr = thr_intr; 90 cotd->thr_func = thr_func; 91 cotd->arg = arg; 92 crit_enter(); 93 pthread_mutex_init(&cotd->mutex, NULL); 94 pthread_cond_init(&cotd->cond, NULL); 95 crit_exit(); 96 97 cotd->pintr = pthread_self(); 98 99 if (thr_intr) { 100 cotd->intr_id = register_int_virtual(1, (void *)thr_intr, 101 cotd, name, 102 NULL, INTR_MPSAFE); 103 } 104 105 /* 106 * The vkernel's cpu_disable_intr() masks signals. We don't want 107 * our coprocessor thread taking any unix signals :-) 108 */ 109 pthread_attr_init(&attr); 110 if (vmm_enabled) { 111 stack = mmap(NULL, KERNEL_STACK_SIZE, 112 PROT_READ|PROT_WRITE|PROT_EXEC, 113 MAP_ANON, -1, 0); 114 if (stack == MAP_FAILED) { 115 panic("Unable to allocate stack for cothread\n"); 116 } 117 pthread_attr_setstack(&attr, stack, KERNEL_STACK_SIZE); 118 } 119 crit_enter(); 120 cpu_mask_all_signals(); 121 pthread_create(&cotd->pthr, &attr, (void *)cothread_thread, cotd); 122 cpu_unmask_all_signals(); 123 crit_exit(); 124 pthread_attr_destroy(&attr); 125 126 return(cotd); 127 } 128 129 /* 130 * Wait for the target thread to terminate and then destroy the cothread 131 * structure. 132 */ 133 void 134 cothread_delete(cothread_t *cotdp) 135 { 136 cothread_t cotd; 137 138 if ((cotd = *cotdp) != NULL) { 139 if (cotd->thr_intr) 140 unregister_int_virtual(cotd->intr_id); 141 crit_enter(); 142 pthread_join(cotd->pthr, NULL); 143 crit_exit(); 144 kfree(cotd, M_DEVBUF); 145 *cotdp = NULL; 146 } 147 } 148 149 static void 150 cothread_thread(void *arg) 151 { 152 cothread_t cotd = arg; 153 154 cpu_mask_all_signals(); /* XXX remove me? should already be masked */ 155 /* 156 * %gs (aka mycpu) is illegal in cothreads. Note that %fs is used 157 * by pthreads. 158 */ 159 /* JG try another approach? */ 160 tls_set_gs(0, sizeof(struct privatespace)); 161 cotd->thr_func(cotd); 162 } 163 164 /* 165 * Called by the cothread to generate an interrupt back to the vkernel. 166 */ 167 void 168 cothread_intr(cothread_t cotd) 169 { 170 pthread_kill(cotd->pintr, SIGALRM); 171 } 172 173 /* 174 * Called by the vkernel to wakeup a cothread. 175 * The cothread must be locked. 176 */ 177 void 178 cothread_signal(cothread_t cotd) 179 { 180 pthread_cond_signal(&cotd->cond); 181 } 182 183 /* 184 * Called by the cothread to wait for the vkernel to call cothread_signal(). 185 * The cothread must be locked. 186 */ 187 void 188 cothread_wait(cothread_t cotd) 189 { 190 pthread_cond_wait(&cotd->cond, &cotd->mutex); 191 } 192 193 /* 194 * Used for systimer support 195 */ 196 void 197 cothread_sleep(cothread_t cotd, struct timespec *ts) 198 { 199 nanosleep(ts, NULL); 200 } 201 202 void 203 cothread_wakeup(cothread_t cotd, struct timespec *ts) 204 { 205 ts->tv_sec = 0; 206 ts->tv_nsec = 0; 207 pthread_kill(cotd->pthr, SIGINT); 208 } 209 210 /* 211 * Typically called by kernel thread or cothread 212 * 213 * These must be a matched pair. We will acquire a critical 214 * section in cothread_lock() and release it in cothread_unlock(). 215 * 216 * We do this to simplify cothread operation to prevent an 217 * interrupt (e.g. vkd_io_intr()) from preempting a vkd_strategy() 218 * call and creating a recursion in the pthread. 219 */ 220 void 221 cothread_lock(cothread_t cotd, int is_cotd) 222 { 223 if (is_cotd) { 224 pthread_mutex_lock(&cotd->mutex); 225 } else { 226 crit_enter_id("cothread"); 227 pthread_mutex_lock(&cotd->mutex); 228 } 229 } 230 231 void 232 cothread_unlock(cothread_t cotd, int is_cotd) 233 { 234 if (is_cotd) { 235 pthread_mutex_unlock(&cotd->mutex); 236 } else { 237 pthread_mutex_unlock(&cotd->mutex); 238 crit_exit_id("cothread"); 239 } 240 } 241