1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright 2009 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */ 28 29 #include <sys/param.h> 30 #include <sys/types.h> 31 #include <sys/sysmacros.h> 32 #include <sys/systm.h> 33 #include <sys/errno.h> 34 #include <sys/syscall.h> 35 #include <sys/proc.h> 36 #include <sys/processor.h> 37 #include <sys/fault.h> 38 #include <sys/ucontext.h> 39 #include <sys/signal.h> 40 #include <sys/unistd.h> 41 #include <sys/procfs.h> 42 #include <sys/prsystm.h> 43 #include <sys/cmn_err.h> 44 #include <sys/debug.h> 45 #include <sys/klwp.h> 46 #include <sys/pool.h> 47 48 /* 49 * System call to create an lwp. 50 * 51 * Notes on the LWP_DETACHED and LWP_DAEMON flags: 52 * 53 * A detached lwp (LWP_DETACHED) cannot be the specific target of 54 * lwp_wait() (it is not joinable), but lwp_wait(0, ...) is required 55 * to sleep until all non-daemon detached lwps have terminated before 56 * returning EDEADLK because a detached lwp might create a non-detached lwp 57 * that could then be returned by lwp_wait(0, ...). See also lwp_detach(). 58 * 59 * A daemon lwp (LWP_DAEMON) is a detached lwp that has the additional 60 * property that it does not affect the termination condition of the 61 * process: The last non-daemon lwp to call lwp_exit() causes the process 62 * to exit and lwp_wait(0, ...) does not sleep waiting for daemon lwps 63 * to terminate. See the block comment before lwp_wait(). 64 */ 65 int 66 syslwp_create(ucontext_t *ucp, int flags, id_t *new_lwp) 67 { 68 klwp_t *lwp; 69 proc_t *p = ttoproc(curthread); 70 kthread_t *t; 71 ucontext_t uc; 72 #ifdef _SYSCALL32_IMPL 73 ucontext32_t uc32; 74 #endif /* _SYSCALL32_IMPL */ 75 k_sigset_t sigmask; 76 int tid; 77 model_t model = get_udatamodel(); 78 uintptr_t thrptr = 0; 79 80 if (flags & ~(LWP_DAEMON|LWP_DETACHED|LWP_SUSPENDED)) 81 return (set_errno(EINVAL)); 82 83 /* 84 * lwp_create() is disallowed for the /proc agent lwp. 85 */ 86 if (curthread == p->p_agenttp) 87 return (set_errno(ENOTSUP)); 88 89 if (model == DATAMODEL_NATIVE) { 90 if (copyin(ucp, &uc, sizeof (ucontext_t))) 91 return (set_errno(EFAULT)); 92 sigutok(&uc.uc_sigmask, &sigmask); 93 #if defined(__i386) 94 /* 95 * libc stashed thrptr into unused kernel %sp. 96 * See setup_context() in libc. 97 */ 98 thrptr = (uint32_t)uc.uc_mcontext.gregs[ESP]; 99 #endif 100 } 101 #ifdef _SYSCALL32_IMPL 102 else { 103 if (copyin(ucp, &uc32, sizeof (ucontext32_t))) 104 return (set_errno(EFAULT)); 105 sigutok(&uc32.uc_sigmask, &sigmask); 106 #if defined(__sparc) 107 ucontext_32ton(&uc32, &uc, NULL, NULL); 108 #else /* __amd64 */ 109 ucontext_32ton(&uc32, &uc); 110 /* 111 * libc stashed thrptr into unused kernel %sp. 112 * See setup_context() in libc. 113 */ 114 thrptr = (uint32_t)uc32.uc_mcontext.gregs[ESP]; 115 #endif 116 } 117 #endif /* _SYSCALL32_IMPL */ 118 119 /* 120 * Tell machine specific code that we are creating a new lwp 121 */ 122 LWP_MMODEL_NEWLWP(); 123 124 (void) save_syscall_args(); /* save args for tracing first */ 125 126 mutex_enter(&curproc->p_lock); 127 pool_barrier_enter(); 128 mutex_exit(&curproc->p_lock); 129 lwp = lwp_create(lwp_rtt, NULL, 0, curproc, TS_STOPPED, 130 curthread->t_pri, &sigmask, curthread->t_cid, 0); 131 mutex_enter(&curproc->p_lock); 132 pool_barrier_exit(); 133 mutex_exit(&curproc->p_lock); 134 if (lwp == NULL) 135 return (set_errno(EAGAIN)); 136 137 lwp_load(lwp, uc.uc_mcontext.gregs, thrptr); 138 139 t = lwptot(lwp); 140 /* 141 * Copy the new lwp's lwpid into the caller's specified buffer. 142 */ 143 if (new_lwp && copyout(&t->t_tid, new_lwp, sizeof (id_t))) { 144 /* 145 * caller's buffer is not writable, return 146 * EFAULT, and terminate new lwp. 147 */ 148 mutex_enter(&p->p_lock); 149 t->t_proc_flag |= TP_EXITLWP; 150 t->t_sig_check = 1; 151 t->t_sysnum = 0; 152 t->t_proc_flag &= ~TP_HOLDLWP; 153 lwp_create_done(t); 154 mutex_exit(&p->p_lock); 155 return (set_errno(EFAULT)); 156 } 157 158 /* 159 * clone callers context, if any. must be invoked 160 * while -not- holding p_lock. 161 */ 162 if (curthread->t_ctx) 163 lwp_createctx(curthread, t); 164 165 /* 166 * copy current contract templates 167 */ 168 lwp_ctmpl_copy(lwp, ttolwp(curthread)); 169 170 mutex_enter(&p->p_lock); 171 /* 172 * Copy the syscall arguments to the new lwp's arg area 173 * for the benefit of debuggers. 174 */ 175 t->t_sysnum = SYS_lwp_create; 176 lwp->lwp_ap = lwp->lwp_arg; 177 lwp->lwp_arg[0] = (long)ucp; 178 lwp->lwp_arg[1] = (long)flags; 179 lwp->lwp_arg[2] = (long)new_lwp; 180 lwp->lwp_argsaved = 1; 181 182 if (!(flags & (LWP_DETACHED|LWP_DAEMON))) 183 t->t_proc_flag |= TP_TWAIT; 184 if (flags & LWP_DAEMON) { 185 t->t_proc_flag |= TP_DAEMON; 186 p->p_lwpdaemon++; 187 } 188 189 tid = (int)t->t_tid; /* for /proc debuggers */ 190 191 /* 192 * We now set the newly-created lwp running. 193 * If it is being created as LWP_SUSPENDED, we leave its 194 * TP_HOLDLWP flag set so it will stop in system call exit. 195 */ 196 if (!(flags & LWP_SUSPENDED)) 197 t->t_proc_flag &= ~TP_HOLDLWP; 198 lwp_create_done(t); 199 mutex_exit(&p->p_lock); 200 201 return (tid); 202 } 203 204 /* 205 * Exit the calling lwp 206 */ 207 void 208 syslwp_exit() 209 { 210 proc_t *p = ttoproc(curthread); 211 212 mutex_enter(&p->p_lock); 213 lwp_exit(); 214 /* NOTREACHED */ 215 } 216