2 * Copyright (c) 2008-2010 The DragonFly Project. All rights reserved.
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
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8 * modification, are permitted provided that the following conditions
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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.
42 #include <sys/interrupt.h>
43 #include <sys/kernel.h>
44 #include <sys/memrange.h>
46 #include <sys/types.h>
48 #include <sys/thread2.h>
51 #include <vm/vm_extern.h>
52 #include <vm/vm_kern.h>
53 #include <vm/vm_object.h>
54 #include <vm/vm_page.h>
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>
70 static void cothread_thread(void *arg);
71 extern int vmm_enabled;
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.
79 cothread_create(void (*thr_func)(cothread_t cotd),
80 void (*thr_intr)(cothread_t cotd),
81 void *arg, const char *name)
87 cotd = kmalloc(sizeof(*cotd), M_DEVBUF, M_WAITOK|M_ZERO);
88 cotd->thr_intr = thr_intr;
89 cotd->thr_func = thr_func;
92 pthread_mutex_init(&cotd->mutex, NULL);
93 pthread_cond_init(&cotd->cond, NULL);
96 cotd->pintr = pthread_self();
99 cotd->intr_id = register_int_virtual(1, (void *)thr_intr,
105 * The vkernel's cpu_disable_intr() masks signals. We don't want
106 * our coprocessor thread taking any unix signals :-)
108 pthread_attr_init(&attr);
110 stack = mmap(NULL, KERNEL_STACK_SIZE,
111 PROT_READ|PROT_WRITE|PROT_EXEC,
113 if (stack == MAP_FAILED) {
114 panic("Unable to allocate stack for cothread\n");
116 pthread_attr_setstack(&attr, stack, KERNEL_STACK_SIZE);
119 cpu_mask_all_signals();
120 pthread_create(&cotd->pthr, &attr, (void *)cothread_thread, cotd);
121 cpu_unmask_all_signals();
123 pthread_attr_destroy(&attr);
129 * Wait for the target thread to terminate and then destroy the cothread
133 cothread_delete(cothread_t *cotdp)
137 if ((cotd = *cotdp) != NULL) {
139 unregister_int_virtual(cotd->intr_id);
141 pthread_join(cotd->pthr, NULL);
143 kfree(cotd, M_DEVBUF);
149 cothread_thread(void *arg)
151 cothread_t cotd = arg;
153 cpu_mask_all_signals(); /* XXX remove me? should already be masked */
155 * %gs (aka mycpu) is illegal in cothreads. Note that %fs is used
158 /* JG try another approach? */
159 tls_set_gs(0, sizeof(struct privatespace));
160 cotd->thr_func(cotd);
164 * Called by the cothread to generate an interrupt back to the vkernel.
167 cothread_intr(cothread_t cotd)
169 pthread_kill(cotd->pintr, SIGALRM);
173 * Called by the vkernel to wakeup a cothread.
174 * The cothread must be locked.
177 cothread_signal(cothread_t cotd)
179 pthread_cond_signal(&cotd->cond);
183 * Called by the cothread to wait for the vkernel to call cothread_signal().
184 * The cothread must be locked.
187 cothread_wait(cothread_t cotd)
189 pthread_cond_wait(&cotd->cond, &cotd->mutex);
193 * Used for systimer support
196 cothread_sleep(cothread_t cotd, struct timespec *ts)
202 cothread_wakeup(cothread_t cotd, struct timespec *ts)
206 pthread_kill(cotd->pthr, SIGINT);
210 * Typically called by kernel thread or cothread
212 * These must be a matched pair. We will acquire a critical
213 * section in cothread_lock() and release it in cothread_unlock().
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.
220 cothread_lock(cothread_t cotd, int is_cotd)
223 pthread_mutex_lock(&cotd->mutex);
225 crit_enter_id("cothread");
226 pthread_mutex_lock(&cotd->mutex);
231 cothread_unlock(cothread_t cotd, int is_cotd)
234 pthread_mutex_unlock(&cotd->mutex);
236 pthread_mutex_unlock(&cotd->mutex);
237 crit_exit_id("cothread");