callcontext.c revision 1.10 1 1.10 pooka /* $NetBSD: callcontext.c,v 1.10 2007/10/21 19:25:58 pooka Exp $ */
2 1.1 pooka
3 1.1 pooka /*
4 1.1 pooka * Copyright (c) 2006 Antti Kantee. All Rights Reserved.
5 1.1 pooka *
6 1.1 pooka * Redistribution and use in source and binary forms, with or without
7 1.1 pooka * modification, are permitted provided that the following conditions
8 1.1 pooka * are met:
9 1.1 pooka * 1. Redistributions of source code must retain the above copyright
10 1.1 pooka * notice, this list of conditions and the following disclaimer.
11 1.1 pooka * 2. Redistributions in binary form must reproduce the above copyright
12 1.1 pooka * notice, this list of conditions and the following disclaimer in the
13 1.1 pooka * documentation and/or other materials provided with the distribution.
14 1.1 pooka *
15 1.1 pooka * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
16 1.1 pooka * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
17 1.1 pooka * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 1.1 pooka * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 1.1 pooka * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 1.1 pooka * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21 1.1 pooka * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 1.1 pooka * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 1.1 pooka * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 1.1 pooka * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 1.1 pooka * SUCH DAMAGE.
26 1.1 pooka */
27 1.1 pooka
28 1.1 pooka #include <sys/cdefs.h>
29 1.1 pooka #if !defined(lint)
30 1.10 pooka __RCSID("$NetBSD: callcontext.c,v 1.10 2007/10/21 19:25:58 pooka Exp $");
31 1.1 pooka #endif /* !lint */
32 1.1 pooka
33 1.1 pooka #include <sys/types.h>
34 1.1 pooka
35 1.1 pooka #include <assert.h>
36 1.9 pooka #include <errno.h>
37 1.1 pooka #include <puffs.h>
38 1.1 pooka #include <stdio.h>
39 1.1 pooka #include <stdlib.h>
40 1.1 pooka #include <string.h>
41 1.3 pooka #include <ucontext.h>
42 1.1 pooka
43 1.1 pooka #include "puffs_priv.h"
44 1.1 pooka
45 1.1 pooka /*
46 1.1 pooka * user stuff
47 1.1 pooka */
48 1.1 pooka
49 1.1 pooka void
50 1.1 pooka puffs_cc_yield(struct puffs_cc *pcc)
51 1.1 pooka {
52 1.1 pooka
53 1.5 pooka assert(pcc->pcc_flags & PCC_REALCC);
54 1.6 pooka pcc->pcc_flags &= ~PCC_BORROWED;
55 1.1 pooka
56 1.1 pooka /* romanes eunt domus */
57 1.1 pooka swapcontext(&pcc->pcc_uc, &pcc->pcc_uc_ret);
58 1.1 pooka }
59 1.1 pooka
60 1.1 pooka void
61 1.1 pooka puffs_cc_continue(struct puffs_cc *pcc)
62 1.1 pooka {
63 1.1 pooka
64 1.5 pooka assert(pcc->pcc_flags & PCC_REALCC);
65 1.5 pooka
66 1.1 pooka /* ramble on */
67 1.1 pooka swapcontext(&pcc->pcc_uc_ret, &pcc->pcc_uc);
68 1.1 pooka }
69 1.1 pooka
70 1.6 pooka /*
71 1.6 pooka * "Borrows" pcc, *NOT* called from pcc owner. Acts like continue.
72 1.6 pooka * So the idea is to use this, give something the context back to
73 1.6 pooka * run to completion and then jump back to where ever this was called
74 1.6 pooka * from after the op dispatching is complete (or if the pcc decides to
75 1.6 pooka * yield again).
76 1.6 pooka */
77 1.6 pooka void
78 1.6 pooka puffs_goto(struct puffs_cc *loanpcc)
79 1.6 pooka {
80 1.6 pooka
81 1.6 pooka assert(loanpcc->pcc_flags & PCC_REALCC);
82 1.6 pooka loanpcc->pcc_flags |= PCC_BORROWED;
83 1.6 pooka
84 1.6 pooka swapcontext(&loanpcc->pcc_uc_ret, &loanpcc->pcc_uc);
85 1.6 pooka }
86 1.6 pooka
87 1.10 pooka void
88 1.10 pooka puffs_cc_schedule(struct puffs_cc *pcc)
89 1.10 pooka {
90 1.10 pooka struct puffs_usermount *pu = pcc->pcc_pu;
91 1.10 pooka
92 1.10 pooka assert(pu->pu_state & PU_INLOOP);
93 1.10 pooka TAILQ_INSERT_TAIL(&pu->pu_sched, pcc, entries);
94 1.10 pooka }
95 1.10 pooka
96 1.1 pooka struct puffs_usermount *
97 1.1 pooka puffs_cc_getusermount(struct puffs_cc *pcc)
98 1.1 pooka {
99 1.1 pooka
100 1.1 pooka return pcc->pcc_pu;
101 1.1 pooka }
102 1.1 pooka
103 1.4 pooka void *
104 1.4 pooka puffs_cc_getspecific(struct puffs_cc *pcc)
105 1.4 pooka {
106 1.4 pooka
107 1.4 pooka return puffs_getspecific(pcc->pcc_pu);
108 1.4 pooka }
109 1.4 pooka
110 1.9 pooka int
111 1.9 pooka puffs_cc_getcaller(struct puffs_cc *pcc, pid_t *pid, lwpid_t *lid)
112 1.9 pooka {
113 1.9 pooka
114 1.9 pooka if ((pcc->pcc_flags & PCC_HASCALLER) == 0) {
115 1.9 pooka errno = ESRCH;
116 1.9 pooka return -1;
117 1.9 pooka }
118 1.9 pooka
119 1.9 pooka if (pid)
120 1.9 pooka *pid = pcc->pcc_pid;
121 1.9 pooka if (lid)
122 1.9 pooka *lid = pcc->pcc_lid;
123 1.9 pooka return 0;
124 1.9 pooka }
125 1.9 pooka
126 1.1 pooka struct puffs_cc *
127 1.2 pooka puffs_cc_create(struct puffs_usermount *pu)
128 1.1 pooka {
129 1.1 pooka struct puffs_cc *volatile pcc;
130 1.1 pooka stack_t *st;
131 1.1 pooka
132 1.1 pooka pcc = malloc(sizeof(struct puffs_cc));
133 1.1 pooka if (!pcc)
134 1.1 pooka return NULL;
135 1.1 pooka memset(pcc, 0, sizeof(struct puffs_cc));
136 1.1 pooka pcc->pcc_pu = pu;
137 1.1 pooka pcc->pcc_flags = PCC_REALCC;
138 1.1 pooka
139 1.1 pooka /* initialize both ucontext's */
140 1.1 pooka if (getcontext(&pcc->pcc_uc) == -1) {
141 1.1 pooka free(pcc);
142 1.1 pooka return NULL;
143 1.1 pooka }
144 1.1 pooka if (getcontext(&pcc->pcc_uc_ret) == -1) {
145 1.1 pooka free(pcc);
146 1.1 pooka return NULL;
147 1.1 pooka }
148 1.1 pooka /* return here. it won't actually be "here" due to swapcontext() */
149 1.1 pooka pcc->pcc_uc.uc_link = &pcc->pcc_uc_ret;
150 1.1 pooka
151 1.1 pooka /* allocate stack for execution */
152 1.1 pooka st = &pcc->pcc_uc.uc_stack;
153 1.1 pooka st->ss_sp = pcc->pcc_stack = malloc(pu->pu_cc_stacksize);
154 1.1 pooka if (st->ss_sp == NULL) {
155 1.1 pooka free(pcc);
156 1.1 pooka return NULL;
157 1.1 pooka }
158 1.1 pooka st->ss_size = pu->pu_cc_stacksize;
159 1.1 pooka st->ss_flags = 0;
160 1.1 pooka
161 1.1 pooka /*
162 1.1 pooka * Give us an initial context to jump to.
163 1.1 pooka *
164 1.1 pooka * XXX: Our manual page says that portable code shouldn't rely on
165 1.1 pooka * being able to pass pointers through makecontext(). kjk says
166 1.1 pooka * that NetBSD code doesn't need to worry about this. uwe says
167 1.1 pooka * it would be like putting a "keep away from children" sign on a
168 1.1 pooka * box of toys. I didn't ask what simon says; he's probably busy
169 1.1 pooka * "fixing" typos in comments.
170 1.1 pooka */
171 1.1 pooka makecontext(&pcc->pcc_uc, (void *)puffs_calldispatcher,
172 1.1 pooka 1, (uintptr_t)pcc);
173 1.1 pooka
174 1.1 pooka return pcc;
175 1.1 pooka }
176 1.1 pooka
177 1.1 pooka void
178 1.9 pooka puffs_cc_setcaller(struct puffs_cc *pcc, pid_t pid, lwpid_t lid)
179 1.9 pooka {
180 1.9 pooka
181 1.9 pooka pcc->pcc_pid = pid;
182 1.9 pooka pcc->pcc_lid = lid;
183 1.9 pooka pcc->pcc_flags |= PCC_HASCALLER;
184 1.9 pooka }
185 1.9 pooka
186 1.9 pooka void
187 1.1 pooka puffs_cc_destroy(struct puffs_cc *pcc)
188 1.1 pooka {
189 1.1 pooka
190 1.1 pooka free(pcc->pcc_stack);
191 1.1 pooka free(pcc);
192 1.1 pooka }
193