1 /*- 2 * Copyright (C) 1994, David Greenman 3 * Copyright (c) 1990, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * the University of Utah, and William Jolitz. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by the University of 20 * California, Berkeley and its contributors. 21 * 4. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * from: @(#)trap.c 7.4 (Berkeley) 5/13/91 38 */ 39 40 #include <sys/cdefs.h> 41 __FBSDID("$FreeBSD$"); 42 43 #include "opt_ktrace.h" 44 #include "opt_mac.h" 45 #ifdef __i386__ 46 #include "opt_npx.h" 47 #endif 48 49 #include <sys/param.h> 50 #include <sys/bus.h> 51 #include <sys/kernel.h> 52 #include <sys/lock.h> 53 #include <sys/mutex.h> 54 #include <sys/proc.h> 55 #include <sys/ktr.h> 56 #include <sys/resourcevar.h> 57 #include <sys/sched.h> 58 #include <sys/signalvar.h> 59 #include <sys/systm.h> 60 #include <sys/vmmeter.h> 61 #ifdef KTRACE 62 #include <sys/uio.h> 63 #include <sys/ktrace.h> 64 #endif 65 66 #include <machine/cpu.h> 67 #include <machine/pcb.h> 68 69 #include <security/mac/mac_framework.h> 70 71 /* 72 * Define the code needed before returning to user mode, for 73 * trap and syscall. 74 * 75 * MPSAFE 76 */ 77 void 78 userret(struct thread *td, struct trapframe *frame) 79 { 80 struct proc *p = td->td_proc; 81 82 CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid, 83 p->p_comm); 84 #ifdef DIAGNOSTIC 85 /* Check that we called signotify() enough. */ 86 PROC_LOCK(p); 87 mtx_lock_spin(&sched_lock); 88 if (SIGPENDING(td) && ((td->td_flags & TDF_NEEDSIGCHK) == 0 || 89 (td->td_flags & TDF_ASTPENDING) == 0)) 90 printf("failed to set signal flags properly for ast()\n"); 91 mtx_unlock_spin(&sched_lock); 92 PROC_UNLOCK(p); 93 #endif 94 95 #ifdef KTRACE 96 KTRUSERRET(td); 97 #endif 98 99 /* 100 * If this thread tickled GEOM, we need to wait for the giggling to 101 * stop before we return to userland 102 */ 103 if (td->td_pflags & TDP_GEOM) 104 g_waitidle(); 105 106 /* 107 * We need to check to see if we have to exit or wait due to a 108 * single threading requirement or some other STOP condition. 109 * Don't bother doing all the work if the stop bits are not set 110 * at this time.. If we miss it, we miss it.. no big deal. 111 */ 112 if (P_SHOULDSTOP(p)) { 113 PROC_LOCK(p); 114 thread_suspend_check(0); /* Can suspend or kill */ 115 PROC_UNLOCK(p); 116 } 117 118 #ifdef KSE 119 /* 120 * Do special thread processing, e.g. upcall tweaking and such. 121 */ 122 if (p->p_flag & P_SA) 123 thread_userret(td, frame); 124 #endif 125 126 /* 127 * Charge system time if profiling. 128 */ 129 if (p->p_flag & P_PROFIL) { 130 131 addupc_task(td, TRAPF_PC(frame), td->td_pticks * psratio); 132 } 133 134 /* 135 * Let the scheduler adjust our priority etc. 136 */ 137 sched_userret(td); 138 KASSERT(td->td_locks == 0, 139 ("userret: Returning with %d locks held.", td->td_locks)); 140 } 141 142 /* 143 * Process an asynchronous software trap. 144 * This is relatively easy. 145 * This function will return with preemption disabled. 146 */ 147 void 148 ast(struct trapframe *framep) 149 { 150 struct thread *td; 151 struct proc *p; 152 #ifdef KSE 153 struct ksegrp *kg; 154 #endif 155 struct rlimit rlim; 156 int sflag; 157 int flags; 158 int sig; 159 #if defined(DEV_NPX) && !defined(SMP) 160 int ucode; 161 ksiginfo_t ksi; 162 #endif 163 164 td = curthread; 165 p = td->td_proc; 166 #ifdef KSE 167 kg = td->td_ksegrp; 168 #endif 169 170 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 171 p->p_comm); 172 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 173 WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode"); 174 mtx_assert(&Giant, MA_NOTOWNED); 175 mtx_assert(&sched_lock, MA_NOTOWNED); 176 td->td_frame = framep; 177 td->td_pticks = 0; 178 179 #ifdef KSE 180 if ((p->p_flag & P_SA) && (td->td_mailbox == NULL)) 181 thread_user_enter(td); 182 #endif 183 184 /* 185 * This updates the p_sflag's for the checks below in one 186 * "atomic" operation with turning off the astpending flag. 187 * If another AST is triggered while we are handling the 188 * AST's saved in sflag, the astpending flag will be set and 189 * ast() will be called again. 190 */ 191 mtx_lock_spin(&sched_lock); 192 flags = td->td_flags; 193 sflag = p->p_sflag; 194 if (p->p_sflag & (PS_ALRMPEND | PS_PROFPEND | PS_XCPU)) 195 p->p_sflag &= ~(PS_ALRMPEND | PS_PROFPEND | PS_XCPU); 196 #ifdef MAC 197 if (p->p_sflag & PS_MACPEND) 198 p->p_sflag &= ~PS_MACPEND; 199 #endif 200 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | 201 TDF_NEEDRESCHED | TDF_INTERRUPT); 202 cnt.v_trap++; 203 mtx_unlock_spin(&sched_lock); 204 205 /* 206 * XXXKSE While the fact that we owe a user profiling 207 * tick is stored per KSE in this code, the statistics 208 * themselves are still stored per process. 209 * This should probably change, by which I mean that 210 * possibly the location of both might change. 211 */ 212 if (td->td_ucred != p->p_ucred) 213 cred_update_thread(td); 214 if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) { 215 addupc_task(td, td->td_profil_addr, td->td_profil_ticks); 216 td->td_profil_ticks = 0; 217 td->td_pflags &= ~TDP_OWEUPC; 218 } 219 if (sflag & PS_ALRMPEND) { 220 PROC_LOCK(p); 221 psignal(p, SIGVTALRM); 222 PROC_UNLOCK(p); 223 } 224 #if defined(DEV_NPX) && !defined(SMP) 225 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 226 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags, 227 PCB_NPXTRAP); 228 ucode = npxtrap(); 229 if (ucode != -1) { 230 ksiginfo_init_trap(&ksi); 231 ksi.ksi_signo = SIGFPE; 232 ksi.ksi_code = ucode; 233 trapsignal(td, &ksi); 234 } 235 } 236 #endif 237 if (sflag & PS_PROFPEND) { 238 PROC_LOCK(p); 239 psignal(p, SIGPROF); 240 PROC_UNLOCK(p); 241 } 242 if (sflag & PS_XCPU) { 243 PROC_LOCK(p); 244 lim_rlimit(p, RLIMIT_CPU, &rlim); 245 mtx_lock_spin(&sched_lock); 246 if (p->p_rux.rux_runtime >= rlim.rlim_max * cpu_tickrate()) { 247 mtx_unlock_spin(&sched_lock); 248 killproc(p, "exceeded maximum CPU limit"); 249 } else { 250 if (p->p_cpulimit < rlim.rlim_max) 251 p->p_cpulimit += 5; 252 mtx_unlock_spin(&sched_lock); 253 psignal(p, SIGXCPU); 254 } 255 PROC_UNLOCK(p); 256 } 257 #ifdef MAC 258 if (sflag & PS_MACPEND) 259 mac_thread_userret(td); 260 #endif 261 if (flags & TDF_NEEDRESCHED) { 262 #ifdef KTRACE 263 if (KTRPOINT(td, KTR_CSW)) 264 ktrcsw(1, 1); 265 #endif 266 mtx_lock_spin(&sched_lock); 267 #ifdef KSE 268 sched_prio(td, kg->kg_user_pri); 269 #else 270 sched_prio(td, td->td_user_pri); 271 #endif 272 mi_switch(SW_INVOL, NULL); 273 mtx_unlock_spin(&sched_lock); 274 #ifdef KTRACE 275 if (KTRPOINT(td, KTR_CSW)) 276 ktrcsw(0, 1); 277 #endif 278 } 279 if (flags & TDF_NEEDSIGCHK) { 280 PROC_LOCK(p); 281 mtx_lock(&p->p_sigacts->ps_mtx); 282 while ((sig = cursig(td)) != 0) 283 postsig(sig); 284 mtx_unlock(&p->p_sigacts->ps_mtx); 285 PROC_UNLOCK(p); 286 } 287 288 userret(td, framep); 289 mtx_assert(&Giant, MA_NOTOWNED); 290 } 291