2 * Copyright (c) 2003,2004,2006 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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36 * Implement upcall registration and dispatch.
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/kernel.h>
43 #include <sys/upcall.h>
44 #include <sys/thread2.h>
45 #include <sys/malloc.h>
46 #include <sys/sysproto.h>
48 #include <sys/signalvar.h>
50 #include <sys/mplock2.h>
53 #include <vm/vm_param.h>
54 #include <vm/vm_kern.h>
56 #include <vm/vm_map.h>
58 #include <machine/cpu.h>
60 MALLOC_DEFINE(M_UPCALL, "upcalls", "upcall registration structures");
63 sigupcall_remote(void *arg)
66 if (lp == lwkt_preempted_proc())
73 * Register an upcall context wrapper and procedure. Note that the
74 * upcall context is set globally for the process, not for each upcall.
76 * ARGS(struct upcall *upc, upcall_func_t ctx, upcall_func_t func, void *data)
81 sys_upc_register(struct upc_register_args *uap)
83 struct lwp *lp = curthread->td_lwp;
84 struct vmspace *vm = curproc->p_vmspace;
88 * Note: inconsequential MP race
90 if (vm->vm_upccount >= UPCALL_MAXCOUNT)
93 vu = kmalloc(sizeof(struct vmupcall), M_UPCALL, M_WAITOK|M_ZERO);
94 vu->vu_ctx = uap->ctxfunc;
95 vu->vu_func = uap->func;
96 vu->vu_data = uap->data;
98 lp->lwp_upcall = uap->upc;
101 if (vm->vm_upcalls != NULL)
102 vu->vu_id = vm->vm_upcalls->vu_id + 1;
104 vu->vu_id = UPC_RESERVED;
105 vu->vu_next = vm->vm_upcalls;
109 uap->sysmsg_result = vu->vu_id;
116 * ARGS(int cmd, int upcid, void *data)
121 sys_upc_control(struct upc_control_args *uap)
123 struct lwp *lp = curthread->td_lwp;
125 struct vmspace *vms = curproc->p_vmspace;
127 struct vmupcall *vu_send;
128 struct vmupcall **vupp;
133 case UPC_CONTROL_DISPATCH:
135 * Dispatch the specified upcall id or the next pending id if -1.
136 * the upcall will be marked pending but an actual upcall will only
137 * occur if userland is not in a critical section and the userland
138 * pending bit is not set.
140 * You can dispatch an upcall associated with your process or another
141 * process sharing the same VM space.
143 error = (uap->upcid == -1) ? 0 : ENOENT;
144 for (vu = vms->vm_upcalls; vu; vu = vu->vu_next) {
145 if (vu->vu_id == uap->upcid ||
147 vu->vu_pending >= (int)(intptr_t)uap->data && vu->vu_lwp == lp)
149 if (vu->vu_pending < (int)(intptr_t)uap->data)
150 vu->vu_pending = (int)(intptr_t)uap->data;
153 targlp->lwp_proc->p_flags |= P_UPCALLPEND; /* XXX lwp flags */
154 if (targlp->lwp_proc->p_flags & P_UPCALLWAIT)
155 wakeup(&targlp->lwp_upcall);
156 if (targlp->lwp_thread->td_gd != mycpu)
157 lwkt_send_ipiq(targlp->lwp_thread->td_gd, sigupcall_remote, targlp);
164 case UPC_CONTROL_NEXT:
166 * This is used by the context code to fetch the next pending upcall.
167 * The context code has two choices: (A) it can drop
168 * upcall->crit_count and set upcall->pending then make this call
169 * unconditionally or * (B) it can drop upcall->crit_count and then
170 * test upcall->pending and only make this call if upcall->pending
171 * is set. If upcall->pending is clear the context code can pop
172 * the upcall stack itself and return without entering into the kernel
173 * again. (B) is more efficient but leaves a small window of
174 * opportunity where multiple upcalls can pushdown the stack.
176 * If another upcall is pending the crit_count will be bumped and
177 * the function, data, and context pointers will be returned in
178 * registers (C cannot call this routine). If no more upcalls are
179 * pending the pending bit will be cleared and the 'data' argument
180 * is expected to be pointing at the upcall context which we will
181 * then pop, returning to the original code that was interrupted
182 * (NOT the context code).
185 for (vu = vms->vm_upcalls; vu; vu = vu->vu_next) {
186 if (vu->vu_lwp == lp && vu->vu_pending) {
193 * vu_send may be NULL, indicating that no more upcalls are pending
194 * for this cpu. We set the userland pending bit based on whether
195 * additional upcalls are pending or not.
197 error = fetchupcall(vu_send, vu != NULL, uap->data);
199 case UPC_CONTROL_DELETE:
201 * Delete the specified upcall id. If the upcall id is -1, delete
202 * all upcall id's associated with the current process.
204 error = (uap->upcid == -1) ? 0 : ENOENT;
205 vupp = &vms->vm_upcalls;
206 while ((vu = *vupp) != NULL) {
207 if (vu->vu_id == uap->upcid ||
208 (uap->upcid == -1 && vu->vu_lwp == lp)
218 case UPC_CONTROL_POLL:
219 case UPC_CONTROL_POLLANDCLEAR:
220 case UPC_CONTROL_WAIT:
222 * If upcid is -1 poll for the first pending upcall and return the
223 * id or 0 if no upcalls are pending.
225 * If upcid is a particular upcall then poll that upcall and return
226 * its pending status (0 or 1). For POLLANDCLEAR, also clear the
227 * pending status. The userland pending bit is not modified by
228 * this call (maybe we should modify it for poll-and-clear).
230 error = (uap->upcid == -1) ? 0 : ENOENT;
231 for (vu = vms->vm_upcalls; vu; vu = vu->vu_next) {
232 if (vu->vu_id == uap->upcid ||
234 vu->vu_pending >= (int)(intptr_t)uap->data && vu->vu_lwp == lp)
237 if (uap->upcid == -1)
238 uap->sysmsg_result = vu->vu_id;
240 uap->sysmsg_result = vu->vu_pending;
241 if (uap->cmd == UPC_CONTROL_POLLANDCLEAR)
246 if (uap->cmd == UPC_CONTROL_WAIT && vu == NULL) {
247 lp->lwp_proc->p_flags |= P_UPCALLWAIT; /* XXX lwp flags */
248 tsleep(&lp->lwp_upcall, PCATCH, "wupcall", 0);
249 lp->lwp_proc->p_flags &= ~P_UPCALLWAIT; /* XXX lwp flags */
261 upc_release(struct vmspace *vm, struct lwp *lp)
263 struct vmupcall **vupp;
266 vupp = &vm->vm_upcalls;
267 while ((vu = *vupp) != NULL) {
268 if (vu->vu_lwp == lp) {
279 * XXX eventually we should sort by vu_pending priority and dispatch
280 * the highest priority upcall first.
283 postupcall(struct lwp *lp)
285 struct vmspace *vm = lp->lwp_proc->p_vmspace;
287 struct vmupcall *vu_send = NULL;
289 for (vu = vm->vm_upcalls; vu; vu = vu->vu_next) {
290 if (vu->vu_lwp == lp && vu->vu_pending) {
299 sendupcall(vu_send, 0);