Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_trap.c
Version:
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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: releng/5.2/sys/kern/subr_trap.c 119781 2003-09-05 22:15:26Z peter $"); 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/mac.h> 54 #include <sys/mutex.h> 55 #include <sys/proc.h> 56 #include <sys/ktr.h> 57 #include <sys/resourcevar.h> 58 #include <sys/sched.h> 59 #include <sys/signalvar.h> 60 #include <sys/systm.h> 61 #include <sys/vmmeter.h> 62 #ifdef KTRACE 63 #include <sys/uio.h> 64 #include <sys/ktrace.h> 65 #endif 66 67 #include <machine/cpu.h> 68 #include <machine/pcb.h> 69 70 /* 71 * Define the code needed before returning to user mode, for 72 * trap and syscall. 73 * 74 * MPSAFE 75 */ 76 void 77 userret(td, frame, oticks) 78 struct thread *td; 79 struct trapframe *frame; 80 u_int oticks; 81 { 82 struct proc *p = td->td_proc; 83 84 CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid, 85 p->p_comm); 86 #ifdef INVARIANTS 87 /* Check that we called signotify() enough. */ 88 PROC_LOCK(p); 89 mtx_lock_spin(&sched_lock); 90 if (SIGPENDING(td) && ((td->td_flags & TDF_NEEDSIGCHK) == 0 || 91 (td->td_flags & TDF_ASTPENDING) == 0)) 92 printf("failed to set signal flags properly for ast()\n"); 93 mtx_unlock_spin(&sched_lock); 94 PROC_UNLOCK(p); 95 #endif 96 97 /* 98 * Let the scheduler adjust our priority etc. 99 */ 100 sched_userret(td); 101 102 /* 103 * We need to check to see if we have to exit or wait due to a 104 * single threading requirement or some other STOP condition. 105 * Don't bother doing all the work if the stop bits are not set 106 * at this time.. If we miss it, we miss it.. no big deal. 107 */ 108 if (P_SHOULDSTOP(p)) { 109 PROC_LOCK(p); 110 thread_suspend_check(0); /* Can suspend or kill */ 111 PROC_UNLOCK(p); 112 } 113 114 /* 115 * Do special thread processing, e.g. upcall tweaking and such. 116 */ 117 if (p->p_flag & P_SA) { 118 thread_userret(td, frame); 119 } 120 121 /* 122 * Charge system time if profiling. 123 */ 124 if (p->p_flag & P_PROFIL) { 125 quad_t ticks; 126 127 mtx_lock_spin(&sched_lock); 128 ticks = td->td_sticks - oticks; 129 mtx_unlock_spin(&sched_lock); 130 addupc_task(td, TRAPF_PC(frame), (u_int)ticks * psratio); 131 } 132 } 133 134 /* 135 * Process an asynchronous software trap. 136 * This is relatively easy. 137 * This function will return with preemption disabled. 138 */ 139 void 140 ast(struct trapframe *framep) 141 { 142 struct thread *td; 143 struct proc *p; 144 struct kse *ke; 145 struct ksegrp *kg; 146 struct rlimit *rlim; 147 u_int prticks, sticks; 148 int sflag; 149 int flags; 150 int sig; 151 #if defined(DEV_NPX) && !defined(SMP) 152 int ucode; 153 #endif 154 155 td = curthread; 156 p = td->td_proc; 157 kg = td->td_ksegrp; 158 159 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 160 p->p_comm); 161 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 162 WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode"); 163 mtx_assert(&Giant, MA_NOTOWNED); 164 mtx_assert(&sched_lock, MA_NOTOWNED); 165 td->td_frame = framep; 166 167 /* 168 * This updates the p_sflag's for the checks below in one 169 * "atomic" operation with turning off the astpending flag. 170 * If another AST is triggered while we are handling the 171 * AST's saved in sflag, the astpending flag will be set and 172 * ast() will be called again. 173 */ 174 mtx_lock_spin(&sched_lock); 175 ke = td->td_kse; 176 sticks = td->td_sticks; 177 flags = td->td_flags; 178 sflag = p->p_sflag; 179 p->p_sflag &= ~(PS_ALRMPEND | PS_PROFPEND | PS_XCPU); 180 #ifdef MAC 181 p->p_sflag &= ~PS_MACPEND; 182 #endif 183 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | 184 TDF_NEEDRESCHED | TDF_OWEUPC | TDF_INTERRUPT); 185 cnt.v_soft++; 186 prticks = 0; 187 if (flags & TDF_OWEUPC && p->p_flag & P_PROFIL) { 188 prticks = p->p_stats->p_prof.pr_ticks; 189 p->p_stats->p_prof.pr_ticks = 0; 190 } 191 mtx_unlock_spin(&sched_lock); 192 /* 193 * XXXKSE While the fact that we owe a user profiling 194 * tick is stored per KSE in this code, the statistics 195 * themselves are still stored per process. 196 * This should probably change, by which I mean that 197 * possibly the location of both might change. 198 */ 199 200 if (td->td_ucred != p->p_ucred) 201 cred_update_thread(td); 202 if (flags & TDF_OWEUPC && p->p_flag & P_PROFIL) 203 addupc_task(td, p->p_stats->p_prof.pr_addr, prticks); 204 if (sflag & PS_ALRMPEND) { 205 PROC_LOCK(p); 206 psignal(p, SIGVTALRM); 207 PROC_UNLOCK(p); 208 } 209 #if defined(DEV_NPX) && !defined(SMP) 210 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 211 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags, 212 PCB_NPXTRAP); 213 ucode = npxtrap(); 214 if (ucode != -1) { 215 trapsignal(td, SIGFPE, ucode); 216 } 217 } 218 #endif 219 if (sflag & PS_PROFPEND) { 220 PROC_LOCK(p); 221 psignal(p, SIGPROF); 222 PROC_UNLOCK(p); 223 } 224 if (sflag & PS_XCPU) { 225 PROC_LOCK(p); 226 rlim = &p->p_rlimit[RLIMIT_CPU]; 227 mtx_lock_spin(&sched_lock); 228 if (p->p_runtime.sec >= rlim->rlim_max) { 229 mtx_unlock_spin(&sched_lock); 230 killproc(p, "exceeded maximum CPU limit"); 231 } else { 232 if (p->p_cpulimit < rlim->rlim_max) 233 p->p_cpulimit += 5; 234 mtx_unlock_spin(&sched_lock); 235 psignal(p, SIGXCPU); 236 } 237 PROC_UNLOCK(p); 238 } 239 #ifdef MAC 240 if (sflag & PS_MACPEND) 241 mac_thread_userret(td); 242 #endif 243 if (flags & TDF_NEEDRESCHED) { 244 #ifdef KTRACE 245 if (KTRPOINT(td, KTR_CSW)) 246 ktrcsw(1, 1); 247 #endif 248 mtx_lock_spin(&sched_lock); 249 sched_prio(td, kg->kg_user_pri); 250 p->p_stats->p_ru.ru_nivcsw++; 251 mi_switch(); 252 mtx_unlock_spin(&sched_lock); 253 #ifdef KTRACE 254 if (KTRPOINT(td, KTR_CSW)) 255 ktrcsw(0, 1); 256 #endif 257 } 258 if (flags & TDF_NEEDSIGCHK) { 259 PROC_LOCK(p); 260 mtx_lock(&p->p_sigacts->ps_mtx); 261 while ((sig = cursig(td)) != 0) 262 postsig(sig); 263 mtx_unlock(&p->p_sigacts->ps_mtx); 264 PROC_UNLOCK(p); 265 } 266 267 userret(td, framep, sticks); 268 #ifdef DIAGNOSTIC 269 cred_free_thread(td); 270 #endif 271 mtx_assert(&Giant, MA_NOTOWNED); 272 }
Cache object: d53b12023be9a7dcb856d7c2b66f787a
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