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_mac.h" 50 #ifdef __i386__ 51 #include "opt_npx.h" 52 #endif 53 #include "opt_sched.h" 54 55 #include <sys/param.h> 56 #include <sys/bus.h> 57 #include <sys/kernel.h> 58 #include <sys/lock.h> 59 #include <sys/mutex.h> 60 #include <sys/pmckern.h> 61 #include <sys/proc.h> 62 #include <sys/ktr.h> 63 #include <sys/resourcevar.h> 64 #include <sys/sched.h> 65 #include <sys/signalvar.h> 66 #include <sys/systm.h> 67 #include <sys/vmmeter.h> 68 #ifdef KTRACE 69 #include <sys/uio.h> 70 #include <sys/ktrace.h> 71 #endif 72 73 #include <machine/cpu.h> 74 #include <machine/pcb.h> 75 76 #include <security/mac/mac_framework.h> 77 78 /* 79 * Define the code needed before returning to user mode, for trap and 80 * syscall. 81 */ 82 void 83 userret(struct thread *td, struct trapframe *frame) 84 { 85 struct proc *p = td->td_proc; 86 87 CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid, 88 td->td_name); 89 #ifdef DIAGNOSTIC 90 /* Check that we called signotify() enough. */ 91 PROC_LOCK(p); 92 thread_lock(td); 93 if (SIGPENDING(td) && ((td->td_flags & TDF_NEEDSIGCHK) == 0 || 94 (td->td_flags & TDF_ASTPENDING) == 0)) 95 printf("failed to set signal flags properly for ast()\n"); 96 thread_unlock(td); 97 PROC_UNLOCK(p); 98 #endif 99 100 #ifdef KTRACE 101 KTRUSERRET(td); 102 #endif 103 104 /* 105 * If this thread tickled GEOM, we need to wait for the giggling to 106 * stop before we return to userland 107 */ 108 if (td->td_pflags & TDP_GEOM) 109 g_waitidle(); 110 111 /* 112 * We need to check to see if we have to exit or wait due to a 113 * single threading requirement or some other STOP condition. 114 * Don't bother doing all the work if the stop bits are not set 115 * at this time.. If we miss it, we miss it.. no big deal. 116 */ 117 if (P_SHOULDSTOP(p)) { 118 PROC_LOCK(p); 119 thread_suspend_check(0); /* Can suspend or kill */ 120 PROC_UNLOCK(p); 121 } 122 123 #ifdef KSE 124 /* 125 * Do special thread processing, e.g. upcall tweaking and such. 126 */ 127 if (p->p_flag & P_SA) 128 thread_userret(td, frame); 129 #endif 130 131 /* 132 * Charge system time if profiling. 133 */ 134 if (p->p_flag & P_PROFIL) { 135 136 addupc_task(td, TRAPF_PC(frame), td->td_pticks * psratio); 137 } 138 139 /* 140 * Let the scheduler adjust our priority etc. 141 */ 142 sched_userret(td); 143 KASSERT(td->td_locks == 0, 144 ("userret: Returning with %d locks held.", td->td_locks)); 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 #if defined(DEV_NPX) && !defined(SMP) 160 int ucode; 161 ksiginfo_t ksi; 162 #endif 163 164 td = curthread; 165 p = td->td_proc; 166 167 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 168 p->p_comm); 169 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 170 WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode"); 171 mtx_assert(&Giant, MA_NOTOWNED); 172 THREAD_LOCK_ASSERT(td, MA_NOTOWNED); 173 td->td_frame = framep; 174 td->td_pticks = 0; 175 176 #ifdef KSE 177 if ((p->p_flag & P_SA) && (td->td_mailbox == NULL)) 178 thread_user_enter(td); 179 #endif 180 181 /* 182 * This updates the td_flag's for the checks below in one 183 * "atomic" operation with turning off the astpending flag. 184 * If another AST is triggered while we are handling the 185 * AST's saved in flags, the astpending flag will be set and 186 * ast() will be called again. 187 */ 188 thread_lock(td); 189 flags = td->td_flags; 190 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | 191 TDF_NEEDRESCHED | TDF_INTERRUPT | TDF_ALRMPEND | TDF_PROFPEND | 192 TDF_MACPEND); 193 thread_unlock(td); 194 PCPU_INC(cnt.v_trap); 195 196 /* 197 * XXXKSE While the fact that we owe a user profiling 198 * tick is stored per thread in this code, the statistics 199 * themselves are still stored per process. 200 * This should probably change, by which I mean that 201 * possibly the location of both might change. 202 */ 203 if (td->td_ucred != p->p_ucred) 204 cred_update_thread(td); 205 if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) { 206 addupc_task(td, td->td_profil_addr, td->td_profil_ticks); 207 td->td_profil_ticks = 0; 208 td->td_pflags &= ~TDP_OWEUPC; 209 } 210 #if defined(HWPMC_HOOKS) 211 if (td->td_pflags & TDP_CALLCHAIN) { 212 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_USER_CALLCHAIN, 213 (void *) framep); 214 td->td_pflags &= ~TDP_CALLCHAIN; 215 } 216 #endif 217 if (flags & TDF_ALRMPEND) { 218 PROC_LOCK(p); 219 psignal(p, SIGVTALRM); 220 PROC_UNLOCK(p); 221 } 222 #if defined(DEV_NPX) && !defined(SMP) 223 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 224 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags, 225 PCB_NPXTRAP); 226 ucode = npxtrap(); 227 if (ucode != -1) { 228 ksiginfo_init_trap(&ksi); 229 ksi.ksi_signo = SIGFPE; 230 ksi.ksi_code = ucode; 231 trapsignal(td, &ksi); 232 } 233 } 234 #endif 235 if (flags & TDF_PROFPEND) { 236 PROC_LOCK(p); 237 psignal(p, SIGPROF); 238 PROC_UNLOCK(p); 239 } 240 #ifdef MAC 241 if (flags & TDF_MACPEND) 242 mac_thread_userret(td); 243 #endif 244 if (flags & TDF_NEEDRESCHED) { 245 #ifdef KTRACE 246 if (KTRPOINT(td, KTR_CSW)) 247 ktrcsw(1, 1); 248 #endif 249 thread_lock(td); 250 sched_prio(td, td->td_user_pri); 251 SCHED_STAT_INC(switch_needresched); 252 mi_switch(SW_INVOL, NULL); 253 thread_unlock(td); 254 #ifdef KTRACE 255 if (KTRPOINT(td, KTR_CSW)) 256 ktrcsw(0, 1); 257 #endif 258 } 259 if (flags & TDF_NEEDSIGCHK) { 260 PROC_LOCK(p); 261 mtx_lock(&p->p_sigacts->ps_mtx); 262 while ((sig = cursig(td)) != 0) 263 postsig(sig); 264 mtx_unlock(&p->p_sigacts->ps_mtx); 265 PROC_UNLOCK(p); 266 } 267 268 userret(td, framep); 269 mtx_assert(&Giant, MA_NOTOWNED); 270 } 271