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 #if 0 103 #ifdef DIAGNOSTIC 104 /* Check that we called signotify() enough. */ 105 PROC_LOCK(p); 106 thread_lock(td); 107 if (SIGPENDING(td) && ((td->td_flags & TDF_NEEDSIGCHK) == 0 || 108 (td->td_flags & TDF_ASTPENDING) == 0)) 109 printf("failed to set signal flags properly for ast()\n"); 110 thread_unlock(td); 111 PROC_UNLOCK(p); 112 #endif 113 #endif 114 #ifdef KTRACE 115 KTRUSERRET(td); 116 #endif 117 /* 118 * If this thread tickled GEOM, we need to wait for the giggling to 119 * stop before we return to userland 120 */ 121 if (td->td_pflags & TDP_GEOM) 122 g_waitidle(); 123 124 /* 125 * Charge system time if profiling. 126 */ 127 if (p->p_flag & P_PROFIL) 128 addupc_task(td, TRAPF_PC(frame), td->td_pticks * psratio); 129 /* 130 * Let the scheduler adjust our priority etc. 131 */ 132 sched_userret(td); 133 KASSERT(td->td_locks == 0, 134 ("userret: Returning with %d locks held.", td->td_locks)); 135 #ifdef VIMAGE 136 /* Unfortunately td_vnet_lpush needs VNET_DEBUG. */ 137 VNET_ASSERT(curvnet == NULL, 138 ("%s: Returning on td %p (pid %d, %s) with vnet %p set in %s", 139 __func__, td, p->p_pid, td->td_name, curvnet, 140 (td->td_vnet_lpush != NULL) ? td->td_vnet_lpush : "N/A")); 141 #endif 142 #ifdef XEN 143 PT_UPDATES_FLUSH(); 144 #endif 145 } 146 147 /* 148 * Process an asynchronous software trap. 149 * This is relatively easy. 150 * This function will return with preemption disabled. 151 */ 152 void 153 ast(struct trapframe *framep) 154 { 155 struct thread *td; 156 struct proc *p; 157 int flags; 158 int sig; 159 160 td = curthread; 161 p = td->td_proc; 162 163 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 164 p->p_comm); 165 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 166 WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode"); 167 mtx_assert(&Giant, MA_NOTOWNED); 168 THREAD_LOCK_ASSERT(td, MA_NOTOWNED); 169 td->td_frame = framep; 170 td->td_pticks = 0; 171 172 /* 173 * This updates the td_flag's for the checks below in one 174 * "atomic" operation with turning off the astpending flag. 175 * If another AST is triggered while we are handling the 176 * AST's saved in flags, the astpending flag will be set and 177 * ast() will be called again. 178 */ 179 thread_lock(td); 180 flags = td->td_flags; 181 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | TDF_NEEDSUSPCHK | 182 TDF_NEEDRESCHED | TDF_ALRMPEND | TDF_PROFPEND | TDF_MACPEND); 183 thread_unlock(td); 184 PCPU_INC(cnt.v_trap); 185 186 if (td->td_ucred != p->p_ucred) 187 cred_update_thread(td); 188 if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) { 189 addupc_task(td, td->td_profil_addr, td->td_profil_ticks); 190 td->td_profil_ticks = 0; 191 td->td_pflags &= ~TDP_OWEUPC; 192 } 193 if (flags & TDF_ALRMPEND) { 194 PROC_LOCK(p); 195 kern_psignal(p, SIGVTALRM); 196 PROC_UNLOCK(p); 197 } 198 if (flags & TDF_PROFPEND) { 199 PROC_LOCK(p); 200 kern_psignal(p, SIGPROF); 201 PROC_UNLOCK(p); 202 } 203 #ifdef MAC 204 if (flags & TDF_MACPEND) 205 mac_thread_userret(td); 206 #endif 207 if (flags & TDF_NEEDRESCHED) { 208 #ifdef KTRACE 209 if (KTRPOINT(td, KTR_CSW)) 210 ktrcsw(1, 1); 211 #endif 212 thread_lock(td); 213 sched_prio(td, td->td_user_pri); 214 mi_switch(SW_INVOL | SWT_NEEDRESCHED, NULL); 215 thread_unlock(td); 216 #ifdef KTRACE 217 if (KTRPOINT(td, KTR_CSW)) 218 ktrcsw(0, 1); 219 #endif 220 } 221 222 /* 223 * Check for signals. Unlocked reads of p_pendingcnt or 224 * p_siglist might cause process-directed signal to be handled 225 * later. 226 */ 227 if (flags & TDF_NEEDSIGCHK || p->p_pendingcnt > 0 || 228 !SIGISEMPTY(p->p_siglist)) { 229 PROC_LOCK(p); 230 mtx_lock(&p->p_sigacts->ps_mtx); 231 while ((sig = cursig(td, SIG_STOP_ALLOWED)) != 0) 232 postsig(sig); 233 mtx_unlock(&p->p_sigacts->ps_mtx); 234 PROC_UNLOCK(p); 235 } 236 /* 237 * We need to check to see if we have to exit or wait due to a 238 * single threading requirement or some other STOP condition. 239 */ 240 if (flags & TDF_NEEDSUSPCHK) { 241 PROC_LOCK(p); 242 thread_suspend_check(0); 243 PROC_UNLOCK(p); 244 } 245 246 if (td->td_pflags & TDP_OLDMASK) { 247 td->td_pflags &= ~TDP_OLDMASK; 248 kern_sigprocmask(td, SIG_SETMASK, &td->td_oldsigmask, NULL, 0); 249 } 250 251 userret(td, framep); 252 mtx_assert(&Giant, MA_NOTOWNED); 253 } 254 255 const char * 256 syscallname(struct proc *p, u_int code) 257 { 258 static const char unknown[] = "unknown"; 259 struct sysentvec *sv; 260 261 sv = p->p_sysent; 262 if (sv->sv_syscallnames == NULL || code >= sv->sv_size) 263 return (unknown); 264 return (sv->sv_syscallnames[code]); 265 } 266