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_ktrace.h" 48 #ifdef __i386__ 49 #include "opt_npx.h" 50 #endif 51 #include "opt_sched.h" 52 53 #include <sys/param.h> 54 #include <sys/bus.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/resourcevar.h> 62 #include <sys/sched.h> 63 #include <sys/signalvar.h> 64 #include <sys/systm.h> 65 #include <sys/vmmeter.h> 66 #ifdef KTRACE 67 #include <sys/uio.h> 68 #include <sys/ktrace.h> 69 #endif 70 71 #include <machine/cpu.h> 72 #include <machine/pcb.h> 73 74 #ifdef XEN 75 #include <vm/vm.h> 76 #include <vm/vm_param.h> 77 #include <vm/pmap.h> 78 #endif 79 80 #include <security/mac/mac_framework.h> 81 82 /* 83 * Define the code needed before returning to user mode, for trap and 84 * syscall. 85 */ 86 void 87 userret(struct thread *td, struct trapframe *frame) 88 { 89 struct proc *p = td->td_proc; 90 91 CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid, 92 td->td_name); 93 #if 0 94 #ifdef DIAGNOSTIC 95 /* Check that we called signotify() enough. */ 96 PROC_LOCK(p); 97 thread_lock(td); 98 if (SIGPENDING(td) && ((td->td_flags & TDF_NEEDSIGCHK) == 0 || 99 (td->td_flags & TDF_ASTPENDING) == 0)) 100 printf("failed to set signal flags properly for ast()\n"); 101 thread_unlock(td); 102 PROC_UNLOCK(p); 103 #endif 104 #endif 105 #ifdef KTRACE 106 KTRUSERRET(td); 107 #endif 108 /* 109 * If this thread tickled GEOM, we need to wait for the giggling to 110 * stop before we return to userland 111 */ 112 if (td->td_pflags & TDP_GEOM) 113 g_waitidle(); 114 115 /* 116 * Charge system time if profiling. 117 */ 118 if (p->p_flag & P_PROFIL) { 119 addupc_task(td, TRAPF_PC(frame), td->td_pticks * psratio); 120 } 121 /* 122 * Let the scheduler adjust our priority etc. 123 */ 124 sched_userret(td); 125 KASSERT(td->td_locks == 0, 126 ("userret: Returning with %d locks held.", td->td_locks)); 127 #ifdef XEN 128 PT_UPDATES_FLUSH(); 129 #endif 130 } 131 132 /* 133 * Process an asynchronous software trap. 134 * This is relatively easy. 135 * This function will return with preemption disabled. 136 */ 137 void 138 ast(struct trapframe *framep) 139 { 140 struct thread *td; 141 struct proc *p; 142 int flags; 143 int sig; 144 #if defined(DEV_NPX) && !defined(SMP) 145 int ucode; 146 ksiginfo_t ksi; 147 #endif 148 149 td = curthread; 150 p = td->td_proc; 151 152 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 153 p->p_comm); 154 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 155 WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode"); 156 mtx_assert(&Giant, MA_NOTOWNED); 157 THREAD_LOCK_ASSERT(td, MA_NOTOWNED); 158 td->td_frame = framep; 159 td->td_pticks = 0; 160 161 /* 162 * This updates the td_flag's for the checks below in one 163 * "atomic" operation with turning off the astpending flag. 164 * If another AST is triggered while we are handling the 165 * AST's saved in flags, the astpending flag will be set and 166 * ast() will be called again. 167 */ 168 thread_lock(td); 169 flags = td->td_flags; 170 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | TDF_NEEDSUSPCHK | 171 TDF_NEEDRESCHED | TDF_ALRMPEND | TDF_PROFPEND | TDF_MACPEND); 172 thread_unlock(td); 173 PCPU_INC(cnt.v_trap); 174 175 if (td->td_ucred != p->p_ucred) 176 cred_update_thread(td); 177 if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) { 178 addupc_task(td, td->td_profil_addr, td->td_profil_ticks); 179 td->td_profil_ticks = 0; 180 td->td_pflags &= ~TDP_OWEUPC; 181 } 182 if (flags & TDF_ALRMPEND) { 183 PROC_LOCK(p); 184 psignal(p, SIGVTALRM); 185 PROC_UNLOCK(p); 186 } 187 #if defined(DEV_NPX) && !defined(SMP) 188 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 189 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags, 190 PCB_NPXTRAP); 191 ucode = npxtrap(); 192 if (ucode != -1) { 193 ksiginfo_init_trap(&ksi); 194 ksi.ksi_signo = SIGFPE; 195 ksi.ksi_code = ucode; 196 trapsignal(td, &ksi); 197 } 198 } 199 #endif 200 if (flags & TDF_PROFPEND) { 201 PROC_LOCK(p); 202 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