1 /* $NetBSD: callcontext.c,v 1.15 2007/12/04 21:24:10 pooka Exp $ */ 2 3 /* 4 * Copyright (c) 2006 Antti Kantee. All Rights Reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 16 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 18 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #include <sys/cdefs.h> 29 #if !defined(lint) 30 __RCSID("$NetBSD: callcontext.c,v 1.15 2007/12/04 21:24:10 pooka Exp $"); 31 #endif /* !lint */ 32 33 #include <sys/types.h> 34 #include <sys/mman.h> 35 36 #include <assert.h> 37 #include <errno.h> 38 #ifdef PUFFS_WITH_THREADS 39 #include <pthread.h> 40 #endif 41 #include <puffs.h> 42 #include <stdio.h> 43 #include <stdlib.h> 44 #include <string.h> 45 #include <ucontext.h> 46 #include <unistd.h> 47 48 #include "puffs_priv.h" 49 50 /* 51 * user stuff 52 */ 53 54 void 55 puffs_cc_yield(struct puffs_cc *pcc) 56 { 57 58 assert(pcc->pcc_flags & PCC_REALCC); 59 pcc->pcc_flags &= ~PCC_BORROWED; 60 61 /* romanes eunt domus */ 62 swapcontext(&pcc->pcc_uc, &pcc->pcc_uc_ret); 63 } 64 65 void 66 puffs_cc_continue(struct puffs_cc *pcc) 67 { 68 69 assert(pcc->pcc_flags & PCC_REALCC); 70 71 /* ramble on */ 72 swapcontext(&pcc->pcc_uc_ret, &pcc->pcc_uc); 73 } 74 75 /* 76 * "Borrows" pcc, *NOT* called from pcc owner. Acts like continue. 77 * So the idea is to use this, give something the context back to 78 * run to completion and then jump back to where ever this was called 79 * from after the op dispatching is complete (or if the pcc decides to 80 * yield again). 81 */ 82 void 83 puffs_goto(struct puffs_cc *loanpcc) 84 { 85 86 assert(loanpcc->pcc_flags & PCC_REALCC); 87 loanpcc->pcc_flags |= PCC_BORROWED; 88 89 swapcontext(&loanpcc->pcc_uc_ret, &loanpcc->pcc_uc); 90 } 91 92 void 93 puffs_cc_schedule(struct puffs_cc *pcc) 94 { 95 struct puffs_usermount *pu = pcc->pcc_pu; 96 97 assert(pu->pu_state & PU_INLOOP); 98 TAILQ_INSERT_TAIL(&pu->pu_sched, pcc, entries); 99 } 100 101 struct puffs_usermount * 102 puffs_cc_getusermount(struct puffs_cc *pcc) 103 { 104 105 return pcc->pcc_pu; 106 } 107 108 void * 109 puffs_cc_getspecific(struct puffs_cc *pcc) 110 { 111 112 return puffs_getspecific(pcc->pcc_pu); 113 } 114 115 int 116 puffs_cc_getcaller(struct puffs_cc *pcc, pid_t *pid, lwpid_t *lid) 117 { 118 119 if ((pcc->pcc_flags & PCC_HASCALLER) == 0) { 120 errno = ESRCH; 121 return -1; 122 } 123 124 if (pid) 125 *pid = pcc->pcc_pid; 126 if (lid) 127 *lid = pcc->pcc_lid; 128 return 0; 129 } 130 131 #ifdef PUFFS_WITH_THREADS 132 int pthread__stackid_setup(void *, size_t, pthread_t *); 133 #endif 134 135 /* for fakecc-users, need only one */ 136 static struct puffs_cc fakecc; 137 138 int 139 puffs_cc_create(struct puffs_usermount *pu, struct puffs_framebuf *pb, 140 int type, struct puffs_cc **pccp) 141 { 142 struct puffs_cc *volatile pcc; 143 size_t stacksize = 1<<pu->pu_cc_stackshift; 144 long psize = sysconf(_SC_PAGESIZE); 145 stack_t *st; 146 void *volatile sp; 147 148 #ifdef PUFFS_WITH_THREADS 149 extern size_t pthread__stacksize; 150 stacksize = pthread__stacksize; 151 #endif 152 153 /* 154 * There are two paths and in the long run we don't have time to 155 * change the one we're on. For non-real cc's, we just simply use 156 * a static copy. For the other cases, we mmap the stack and 157 * manually reserve a bit from the top for the data structure 158 * (or, well, the bottom). 159 * 160 * XXX: threaded mode doesn't work very well now. Not that it's 161 * supported anyhow. 162 */ 163 if (type == PCC_FAKECC) { 164 pcc = &fakecc; 165 sp = NULL; 166 } else { 167 sp = mmap(NULL, stacksize, PROT_READ|PROT_WRITE, 168 MAP_ANON|MAP_PRIVATE|MAP_ALIGNED(pu->pu_cc_stackshift), 169 -1, 0); 170 if (sp == MAP_FAILED) 171 return -1; 172 173 pcc = sp; 174 sp = (uint8_t *)sp + psize; 175 } 176 177 memset(pcc, 0, sizeof(struct puffs_cc)); 178 pcc->pcc_pu = pu; 179 pcc->pcc_pb = pb; 180 pcc->pcc_flags = type; 181 182 /* Not a real cc? Don't need to init more */ 183 if (pcc->pcc_flags != PCC_REALCC) 184 goto out; 185 186 /* initialize both ucontext's */ 187 if (getcontext(&pcc->pcc_uc) == -1) { 188 munmap(pcc, stacksize); 189 return -1; 190 } 191 if (getcontext(&pcc->pcc_uc_ret) == -1) { 192 munmap(pcc, stacksize); 193 return -1; 194 } 195 /* return here. it won't actually be "here" due to swapcontext() */ 196 pcc->pcc_uc.uc_link = &pcc->pcc_uc_ret; 197 198 /* allocate stack for execution */ 199 st = &pcc->pcc_uc.uc_stack; 200 201 st->ss_sp = pcc->pcc_stack = sp; 202 st->ss_size = stacksize - psize; 203 st->ss_flags = 0; 204 205 #ifdef PUFFS_WITH_THREADS 206 { 207 pthread_t pt; 208 extern int __isthreaded; 209 if (__isthreaded) 210 pthread__stackid_setup(sp, stacksize /* XXXb0rked */, &pt); 211 } 212 #endif 213 214 /* 215 * Give us an initial context to jump to. 216 * 217 * XXX: Our manual page says that portable code shouldn't rely on 218 * being able to pass pointers through makecontext(). kjk says 219 * that NetBSD code doesn't need to worry about this. uwe says 220 * it would be like putting a "keep away from children" sign on a 221 * box of toys. I didn't ask what simon says; he's probably busy 222 * "fixing" typos in comments. 223 */ 224 makecontext(&pcc->pcc_uc, (void *)puffs_calldispatcher, 225 1, (uintptr_t)pcc); 226 227 out: 228 *pccp = pcc; 229 return 0; 230 } 231 232 void 233 puffs_cc_setcaller(struct puffs_cc *pcc, pid_t pid, lwpid_t lid) 234 { 235 236 pcc->pcc_pid = pid; 237 pcc->pcc_lid = lid; 238 pcc->pcc_flags |= PCC_HASCALLER; 239 } 240 241 void 242 puffs_cc_destroy(struct puffs_cc *pcc) 243 { 244 struct puffs_usermount *pu = pcc->pcc_pu; 245 size_t stacksize = 1<<pu->pu_cc_stackshift; 246 247 #ifdef PUFFS_WITH_THREADS 248 extern size_t pthread__stacksize; 249 stacksize = pthread__stacksize; 250 #endif 251 252 if ((pcc->pcc_flags & PCC_FAKECC) == 0) 253 munmap(pcc, stacksize); 254 } 255 256 struct puffs_cc * 257 puffs_cc_getcc(struct puffs_usermount *pu) 258 { 259 extern int puffs_fakecc, puffs_usethreads; 260 size_t stacksize = 1<<pu->pu_cc_stackshift; 261 uintptr_t bottom; 262 263 if (puffs_fakecc) 264 return &fakecc; 265 #ifndef PUFFS_WITH_THREADS 266 if (puffs_usethreads) 267 return &fakecc; 268 #endif 269 270 bottom = ((uintptr_t)&bottom) & ~(stacksize-1); 271 return (struct puffs_cc *)bottom; 272 } 273