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 } 94 #ifdef _SYSCALL32_IMPL 95 else { 96 if (copyin(ucp, &uc32, sizeof (ucontext32_t))) 97 return (set_errno(EFAULT)); 98 sigutok(&uc32.uc_sigmask, &sigmask); 99 #if defined(__sparc) 100 ucontext_32ton(&uc32, &uc, NULL, NULL); 101 #else /* __amd64 */ 102 ucontext_32ton(&uc32, &uc); 103 /* 104 * libc stashed thrptr into unused kernel %sp. 105 * See setup_context() in libc. 106 */ 107 thrptr = (uint32_t)uc32.uc_mcontext.gregs[ESP]; 108 #endif 109 } 110 #endif /* _SYSCALL32_IMPL */ 111 112 /* 113 * Tell machine specific code that we are creating a new lwp 114 */ 115 LWP_MMODEL_NEWLWP(); 116 117 (void) save_syscall_args(); /* save args for tracing first */ 118 119 mutex_enter(&curproc->p_lock); 120 pool_barrier_enter(); 121 mutex_exit(&curproc->p_lock); 122 lwp = lwp_create(lwp_rtt, NULL, 0, curproc, TS_STOPPED, 123 curthread->t_pri, &sigmask, curthread->t_cid, 0); 124 mutex_enter(&curproc->p_lock); 125 pool_barrier_exit(); 126 mutex_exit(&curproc->p_lock); 127 if (lwp == NULL) 128 return (set_errno(EAGAIN)); 129 130 lwp_load(lwp, uc.uc_mcontext.gregs, thrptr); 131 132 t = lwptot(lwp); 133 /* 134 * Copy the new lwp's lwpid into the caller's specified buffer. 135 */ 136 if (new_lwp && copyout(&t->t_tid, new_lwp, sizeof (id_t))) { 137 /* 138 * caller's buffer is not writable, return 139 * EFAULT, and terminate new lwp. 140 */ 141 mutex_enter(&p->p_lock); 142 t->t_proc_flag |= TP_EXITLWP; 143 t->t_sig_check = 1; 144 t->t_sysnum = 0; 145 t->t_proc_flag &= ~TP_HOLDLWP; 146 lwp_create_done(t); 147 mutex_exit(&p->p_lock); 148 return (set_errno(EFAULT)); 149 } 150 151 /* 152 * clone callers context, if any. must be invoked 153 * while -not- holding p_lock. 154 */ 155 if (curthread->t_ctx) 156 lwp_createctx(curthread, t); 157 158 /* 159 * copy current contract templates 160 */ 161 lwp_ctmpl_copy(lwp, ttolwp(curthread)); 162 163 mutex_enter(&p->p_lock); 164 /* 165 * Copy the syscall arguments to the new lwp's arg area 166 * for the benefit of debuggers. 167 */ 168 t->t_sysnum = SYS_lwp_create; 169 lwp->lwp_ap = lwp->lwp_arg; 170 lwp->lwp_arg[0] = (long)ucp; 171 lwp->lwp_arg[1] = (long)flags; 172 lwp->lwp_arg[2] = (long)new_lwp; 173 lwp->lwp_argsaved = 1; 174 175 if (!(flags & (LWP_DETACHED|LWP_DAEMON))) 176 t->t_proc_flag |= TP_TWAIT; 177 if (flags & LWP_DAEMON) { 178 t->t_proc_flag |= TP_DAEMON; 179 p->p_lwpdaemon++; 180 } 181 182 tid = (int)t->t_tid; /* for /proc debuggers */ 183 184 /* 185 * We now set the newly-created lwp running. 186 * If it is being created as LWP_SUSPENDED, we leave its 187 * TP_HOLDLWP flag set so it will stop in system call exit. 188 */ 189 if (!(flags & LWP_SUSPENDED)) 190 t->t_proc_flag &= ~TP_HOLDLWP; 191 lwp_create_done(t); 192 mutex_exit(&p->p_lock); 193 194 return (tid); 195 } 196 197 /* 198 * Exit the calling lwp 199 */ 200 void 201 syslwp_exit() 202 { 203 proc_t *p = ttoproc(curthread); 204 205 mutex_enter(&p->p_lock); 206 lwp_exit(); 207 /* NOTREACHED */ 208 } 209