1 /*- 2 * Copyright (C) 1994, David Greenman 3 * Copyright (c) 1990, 1993 4 * The Regents of the University of California. All rights reserved. 5 * Copyright (c) 2007 The FreeBSD Foundation 6 * 7 * This code is derived from software contributed to Berkeley by 8 * the University of Utah, and William Jolitz. 9 * 10 * Portions of this software were developed by A. Joseph Koshy under 11 * sponsorship from the FreeBSD Foundation and Google, Inc. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. All advertising materials mentioning features or use of this software 22 * must display the following acknowledgement: 23 * This product includes software developed by the University of 24 * California, Berkeley and its contributors. 25 * 4. Neither the name of the University nor the names of its contributors 26 * may be used to endorse or promote products derived from this software 27 * without specific prior written permission. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 32 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 39 * SUCH DAMAGE. 40 * 41 * from: @(#)trap.c 7.4 (Berkeley) 5/13/91 42 */ 43 44 #include <sys/cdefs.h> 45 __FBSDID("$FreeBSD$"); 46 47 #include "opt_capsicum.h" 48 #include "opt_ktrace.h" 49 #include "opt_kdtrace.h" 50 #include "opt_sched.h" 51 52 #include <sys/param.h> 53 #include <sys/bus.h> 54 #include <sys/capability.h> 55 #include <sys/kernel.h> 56 #include <sys/lock.h> 57 #include <sys/mutex.h> 58 #include <sys/pmckern.h> 59 #include <sys/proc.h> 60 #include <sys/ktr.h> 61 #include <sys/pioctl.h> 62 #include <sys/ptrace.h> 63 #include <sys/resourcevar.h> 64 #include <sys/sched.h> 65 #include <sys/signalvar.h> 66 #include <sys/syscall.h> 67 #include <sys/syscallsubr.h> 68 #include <sys/sysent.h> 69 #include <sys/systm.h> 70 #include <sys/vmmeter.h> 71 #ifdef KTRACE 72 #include <sys/uio.h> 73 #include <sys/ktrace.h> 74 #endif 75 #include <security/audit/audit.h> 76 77 #include <machine/cpu.h> 78 79 #ifdef VIMAGE 80 #include <net/vnet.h> 81 #endif 82 83 #ifdef XEN 84 #include <vm/vm.h> 85 #include <vm/vm_param.h> 86 #include <vm/pmap.h> 87 #endif 88 89 #include <security/mac/mac_framework.h> 90 91 /* 92 * Define the code needed before returning to user mode, for trap and 93 * syscall. 94 */ 95 void 96 userret(struct thread *td, struct trapframe *frame) 97 { 98 struct proc *p = td->td_proc; 99 100 CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid, 101 td->td_name); 102 KASSERT((p->p_flag & P_WEXIT) == 0, 103 ("Exiting process returns to usermode")); 104 #if 0 105 #ifdef DIAGNOSTIC 106 /* Check that we called signotify() enough. */ 107 PROC_LOCK(p); 108 thread_lock(td); 109 if (SIGPENDING(td) && ((td->td_flags & TDF_NEEDSIGCHK) == 0 || 110 (td->td_flags & TDF_ASTPENDING) == 0)) 111 printf("failed to set signal flags properly for ast()\n"); 112 thread_unlock(td); 113 PROC_UNLOCK(p); 114 #endif 115 #endif 116 #ifdef KTRACE 117 KTRUSERRET(td); 118 #endif 119 /* 120 * If this thread tickled GEOM, we need to wait for the giggling to 121 * stop before we return to userland 122 */ 123 if (td->td_pflags & TDP_GEOM) 124 g_waitidle(); 125 126 /* 127 * Charge system time if profiling. 128 */ 129 if (p->p_flag & P_PROFIL) 130 addupc_task(td, TRAPF_PC(frame), td->td_pticks * psratio); 131 /* 132 * Let the scheduler adjust our priority etc. 133 */ 134 sched_userret(td); 135 KASSERT(td->td_locks == 0, 136 ("userret: Returning with %d locks held.", td->td_locks)); 137 #ifdef VIMAGE 138 /* Unfortunately td_vnet_lpush needs VNET_DEBUG. */ 139 VNET_ASSERT(curvnet == NULL, 140 ("%s: Returning on td %p (pid %d, %s) with vnet %p set in %s", 141 __func__, td, p->p_pid, td->td_name, curvnet, 142 (td->td_vnet_lpush != NULL) ? td->td_vnet_lpush : "N/A")); 143 #endif 144 #ifdef XEN 145 PT_UPDATES_FLUSH(); 146 #endif 147 } 148 149 /* 150 * Process an asynchronous software trap. 151 * This is relatively easy. 152 * This function will return with preemption disabled. 153 */ 154 void 155 ast(struct trapframe *framep) 156 { 157 struct thread *td; 158 struct proc *p; 159 int flags; 160 int sig; 161 162 td = curthread; 163 p = td->td_proc; 164 165 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 166 p->p_comm); 167 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 168 WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode"); 169 mtx_assert(&Giant, MA_NOTOWNED); 170 THREAD_LOCK_ASSERT(td, MA_NOTOWNED); 171 td->td_frame = framep; 172 td->td_pticks = 0; 173 174 /* 175 * This updates the td_flag's for the checks below in one 176 * "atomic" operation with turning off the astpending flag. 177 * If another AST is triggered while we are handling the 178 * AST's saved in flags, the astpending flag will be set and 179 * ast() will be called again. 180 */ 181 thread_lock(td); 182 flags = td->td_flags; 183 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | TDF_NEEDSUSPCHK | 184 TDF_NEEDRESCHED | TDF_ALRMPEND | TDF_PROFPEND | TDF_MACPEND); 185 thread_unlock(td); 186 PCPU_INC(cnt.v_trap); 187 188 if (td->td_ucred != p->p_ucred) 189 cred_update_thread(td); 190 if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) { 191 addupc_task(td, td->td_profil_addr, td->td_profil_ticks); 192 td->td_profil_ticks = 0; 193 td->td_pflags &= ~TDP_OWEUPC; 194 } 195 if (flags & TDF_ALRMPEND) { 196 PROC_LOCK(p); 197 kern_psignal(p, SIGVTALRM); 198 PROC_UNLOCK(p); 199 } 200 if (flags & TDF_PROFPEND) { 201 PROC_LOCK(p); 202 kern_psignal(p, SIGPROF); 203 PROC_UNLOCK(p); 204 } 205 #ifdef MAC 206 if (flags & TDF_MACPEND) 207 mac_thread_userret(td); 208 #endif 209 if (flags & TDF_NEEDRESCHED) { 210 #ifdef KTRACE 211 if (KTRPOINT(td, KTR_CSW)) 212 ktrcsw(1, 1); 213 #endif 214 thread_lock(td); 215 sched_prio(td, td->td_user_pri); 216 mi_switch(SW_INVOL | SWT_NEEDRESCHED, NULL); 217 thread_unlock(td); 218 #ifdef KTRACE 219 if (KTRPOINT(td, KTR_CSW)) 220 ktrcsw(0, 1); 221 #endif 222 } 223 224 /* 225 * Check for signals. Unlocked reads of p_pendingcnt or 226 * p_siglist might cause process-directed signal to be handled 227 * later. 228 */ 229 if (flags & TDF_NEEDSIGCHK || p->p_pendingcnt > 0 || 230 !SIGISEMPTY(p->p_siglist)) { 231 PROC_LOCK(p); 232 mtx_lock(&p->p_sigacts->ps_mtx); 233 while ((sig = cursig(td, SIG_STOP_ALLOWED)) != 0) 234 postsig(sig); 235 mtx_unlock(&p->p_sigacts->ps_mtx); 236 PROC_UNLOCK(p); 237 } 238 /* 239 * We need to check to see if we have to exit or wait due to a 240 * single threading requirement or some other STOP condition. 241 */ 242 if (flags & TDF_NEEDSUSPCHK) { 243 PROC_LOCK(p); 244 thread_suspend_check(0); 245 PROC_UNLOCK(p); 246 } 247 248 if (td->td_pflags & TDP_OLDMASK) { 249 td->td_pflags &= ~TDP_OLDMASK; 250 kern_sigprocmask(td, SIG_SETMASK, &td->td_oldsigmask, NULL, 0); 251 } 252 253 userret(td, framep); 254 mtx_assert(&Giant, MA_NOTOWNED); 255 } 256 257 const char * 258 syscallname(struct proc *p, u_int code) 259 { 260 static const char unknown[] = "unknown"; 261 struct sysentvec *sv; 262 263 sv = p->p_sysent; 264 if (sv->sv_syscallnames == NULL || code >= sv->sv_size) 265 return (unknown); 266 return (sv->sv_syscallnames[code]); 267 } 268