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_hwpmc_hooks.h" 48 #include "opt_ktrace.h" 49 #include "opt_sched.h" 50 51 #include <sys/param.h> 52 #include <sys/bus.h> 53 #include <sys/capsicum.h> 54 #include <sys/kernel.h> 55 #include <sys/lock.h> 56 #include <sys/mutex.h> 57 #include <sys/pmckern.h> 58 #include <sys/proc.h> 59 #include <sys/ktr.h> 60 #include <sys/pioctl.h> 61 #include <sys/ptrace.h> 62 #include <sys/racct.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 HWPMC_HOOKS 84 #include <sys/pmckern.h> 85 #endif 86 87 #include <security/mac/mac_framework.h> 88 89 void (*softdep_ast_cleanup)(void); 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 if (softdep_ast_cleanup != NULL) 120 softdep_ast_cleanup(); 121 122 /* 123 * If this thread tickled GEOM, we need to wait for the giggling to 124 * stop before we return to userland 125 */ 126 if (td->td_pflags & TDP_GEOM) 127 g_waitidle(); 128 129 /* 130 * Charge system time if profiling. 131 */ 132 if (p->p_flag & P_PROFIL) 133 addupc_task(td, TRAPF_PC(frame), td->td_pticks * psratio); 134 /* 135 * Let the scheduler adjust our priority etc. 136 */ 137 sched_userret(td); 138 139 /* 140 * Check for misbehavior. 141 * 142 * In case there is a callchain tracing ongoing because of 143 * hwpmc(4), skip the scheduler pinning check. 144 * hwpmc(4) subsystem, infact, will collect callchain informations 145 * at ast() checkpoint, which is past userret(). 146 */ 147 WITNESS_WARN(WARN_PANIC, NULL, "userret: returning"); 148 KASSERT(td->td_critnest == 0, 149 ("userret: Returning in a critical section")); 150 KASSERT(td->td_locks == 0, 151 ("userret: Returning with %d locks held", td->td_locks)); 152 KASSERT(td->td_rw_rlocks == 0, 153 ("userret: Returning with %d rwlocks held in read mode", 154 td->td_rw_rlocks)); 155 KASSERT((td->td_pflags & TDP_NOFAULTING) == 0, 156 ("userret: Returning with pagefaults disabled")); 157 KASSERT(td->td_no_sleeping == 0, 158 ("userret: Returning with sleep disabled")); 159 KASSERT(td->td_pinned == 0 || (td->td_pflags & TDP_CALLCHAIN) != 0, 160 ("userret: Returning with with pinned thread")); 161 KASSERT(td->td_vp_reserv == 0, 162 ("userret: Returning while holding vnode reservation")); 163 KASSERT((td->td_flags & TDF_SBDRY) == 0, 164 ("userret: Returning with stop signals deferred")); 165 KASSERT(td->td_su == NULL, 166 ("userret: Returning with SU cleanup request not handled")); 167 #ifdef VIMAGE 168 /* Unfortunately td_vnet_lpush needs VNET_DEBUG. */ 169 VNET_ASSERT(curvnet == NULL, 170 ("%s: Returning on td %p (pid %d, %s) with vnet %p set in %s", 171 __func__, td, p->p_pid, td->td_name, curvnet, 172 (td->td_vnet_lpush != NULL) ? td->td_vnet_lpush : "N/A")); 173 #endif 174 #ifdef RACCT 175 if (racct_enable && p->p_throttled != 0) { 176 PROC_LOCK(p); 177 while (p->p_throttled != 0) { 178 msleep(p->p_racct, &p->p_mtx, 0, "racct", 179 p->p_throttled < 0 ? 0 : p->p_throttled); 180 if (p->p_throttled > 0) 181 p->p_throttled = 0; 182 } 183 PROC_UNLOCK(p); 184 } 185 #endif 186 } 187 188 /* 189 * Process an asynchronous software trap. 190 * This is relatively easy. 191 * This function will return with preemption disabled. 192 */ 193 void 194 ast(struct trapframe *framep) 195 { 196 struct thread *td; 197 struct proc *p; 198 int flags; 199 int sig; 200 201 td = curthread; 202 p = td->td_proc; 203 204 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 205 p->p_comm); 206 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 207 WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode"); 208 mtx_assert(&Giant, MA_NOTOWNED); 209 THREAD_LOCK_ASSERT(td, MA_NOTOWNED); 210 td->td_frame = framep; 211 td->td_pticks = 0; 212 213 /* 214 * This updates the td_flag's for the checks below in one 215 * "atomic" operation with turning off the astpending flag. 216 * If another AST is triggered while we are handling the 217 * AST's saved in flags, the astpending flag will be set and 218 * ast() will be called again. 219 */ 220 thread_lock(td); 221 flags = td->td_flags; 222 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | TDF_NEEDSUSPCHK | 223 TDF_NEEDRESCHED | TDF_ALRMPEND | TDF_PROFPEND | TDF_MACPEND); 224 thread_unlock(td); 225 PCPU_INC(cnt.v_trap); 226 227 if (td->td_cowgen != p->p_cowgen) 228 thread_cow_update(td); 229 if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) { 230 addupc_task(td, td->td_profil_addr, td->td_profil_ticks); 231 td->td_profil_ticks = 0; 232 td->td_pflags &= ~TDP_OWEUPC; 233 } 234 #ifdef HWPMC_HOOKS 235 /* Handle Software PMC callchain capture. */ 236 if (PMC_IS_PENDING_CALLCHAIN(td)) 237 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_USER_CALLCHAIN_SOFT, (void *) framep); 238 #endif 239 if (flags & TDF_ALRMPEND) { 240 PROC_LOCK(p); 241 kern_psignal(p, SIGVTALRM); 242 PROC_UNLOCK(p); 243 } 244 if (flags & TDF_PROFPEND) { 245 PROC_LOCK(p); 246 kern_psignal(p, SIGPROF); 247 PROC_UNLOCK(p); 248 } 249 #ifdef MAC 250 if (flags & TDF_MACPEND) 251 mac_thread_userret(td); 252 #endif 253 if (flags & TDF_NEEDRESCHED) { 254 #ifdef KTRACE 255 if (KTRPOINT(td, KTR_CSW)) 256 ktrcsw(1, 1, __func__); 257 #endif 258 thread_lock(td); 259 sched_prio(td, td->td_user_pri); 260 mi_switch(SW_INVOL | SWT_NEEDRESCHED, NULL); 261 thread_unlock(td); 262 #ifdef KTRACE 263 if (KTRPOINT(td, KTR_CSW)) 264 ktrcsw(0, 1, __func__); 265 #endif 266 } 267 268 /* 269 * Check for signals. Unlocked reads of p_pendingcnt or 270 * p_siglist might cause process-directed signal to be handled 271 * later. 272 */ 273 if (flags & TDF_NEEDSIGCHK || p->p_pendingcnt > 0 || 274 !SIGISEMPTY(p->p_siglist)) { 275 PROC_LOCK(p); 276 mtx_lock(&p->p_sigacts->ps_mtx); 277 while ((sig = cursig(td)) != 0) 278 postsig(sig); 279 mtx_unlock(&p->p_sigacts->ps_mtx); 280 PROC_UNLOCK(p); 281 } 282 /* 283 * We need to check to see if we have to exit or wait due to a 284 * single threading requirement or some other STOP condition. 285 */ 286 if (flags & TDF_NEEDSUSPCHK) { 287 PROC_LOCK(p); 288 thread_suspend_check(0); 289 PROC_UNLOCK(p); 290 } 291 292 if (td->td_pflags & TDP_OLDMASK) { 293 td->td_pflags &= ~TDP_OLDMASK; 294 kern_sigprocmask(td, SIG_SETMASK, &td->td_oldsigmask, NULL, 0); 295 } 296 297 userret(td, framep); 298 } 299 300 const char * 301 syscallname(struct proc *p, u_int code) 302 { 303 static const char unknown[] = "unknown"; 304 struct sysentvec *sv; 305 306 sv = p->p_sysent; 307 if (sv->sv_syscallnames == NULL || code >= sv->sv_size) 308 return (unknown); 309 return (sv->sv_syscallnames[code]); 310 } 311