subr_trap.c revision 104964
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 * $FreeBSD: head/sys/kern/subr_trap.c 104964 2002-10-12 05:32:24Z jeff $ 39 */ 40 41#include "opt_mac.h" 42#ifdef __i386__ 43#include "opt_npx.h" 44#endif 45 46#include <sys/param.h> 47#include <sys/bus.h> 48#include <sys/kernel.h> 49#include <sys/lock.h> 50#include <sys/mac.h> 51#include <sys/mutex.h> 52#include <sys/proc.h> 53#include <sys/kse.h> 54#include <sys/ktr.h> 55#include <sys/resourcevar.h> 56#include <sys/sched.h> 57#include <sys/signalvar.h> 58#include <sys/systm.h> 59#include <sys/vmmeter.h> 60#include <machine/cpu.h> 61#include <machine/pcb.h> 62 63/* 64 * Define the code needed before returning to user mode, for 65 * trap and syscall. 66 * 67 * MPSAFE 68 */ 69void 70userret(td, frame, oticks) 71 struct thread *td; 72 struct trapframe *frame; 73 u_int oticks; 74{ 75 struct proc *p = td->td_proc; 76 struct kse *ke = td->td_kse; 77 78 CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid, 79 p->p_comm); 80#ifdef INVARIANTS 81 /* Check that we called signotify() enough. */ 82 mtx_lock(&Giant); 83 PROC_LOCK(p); 84 mtx_lock_spin(&sched_lock); 85 if (SIGPENDING(p) && ((p->p_sflag & PS_NEEDSIGCHK) == 0 || 86 (td->td_kse->ke_flags & KEF_ASTPENDING) == 0)) 87 printf("failed to set signal flags properly for ast()\n"); 88 mtx_unlock_spin(&sched_lock); 89 PROC_UNLOCK(p); 90 mtx_unlock(&Giant); 91#endif 92 93#ifdef MAC 94 mac_thread_userret(td); 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_KSES) { 118 thread_userret(td, frame); 119 /* printf("KSE thread returned"); */ 120 } 121 122 /* 123 * Charge system time if profiling. 124 * 125 * XXX should move PS_PROFIL to a place that can obviously be 126 * accessed safely without sched_lock. 127 */ 128 if (p->p_sflag & PS_PROFIL) { 129 quad_t ticks; 130 131 mtx_lock_spin(&sched_lock); 132 ticks = ke->ke_sticks - oticks; 133 mtx_unlock_spin(&sched_lock); 134 addupc_task(ke, TRAPF_PC(frame), (u_int)ticks * psratio); 135 } 136} 137 138/* 139 * Process an asynchronous software trap. 140 * This is relatively easy. 141 * This function will return with preemption disabled. 142 */ 143void 144ast(struct trapframe *framep) 145{ 146 struct thread *td; 147 struct proc *p; 148 struct kse *ke; 149 struct ksegrp *kg; 150 struct rlimit *rlim; 151 u_int prticks, sticks; 152 int sflag; 153 int flags; 154 int sig; 155#if defined(DEV_NPX) && !defined(SMP) 156 int ucode; 157#endif 158 159 td = curthread; 160 p = td->td_proc; 161 kg = td->td_ksegrp; 162 163 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 164 p->p_comm); 165 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 166#ifdef WITNESS 167 if (witness_list(td)) 168 panic("Returning to user mode with mutex(s) held"); 169#endif 170 mtx_assert(&Giant, MA_NOTOWNED); 171 mtx_assert(&sched_lock, MA_NOTOWNED); 172 td->td_frame = framep; 173 174 /* 175 * This updates the p_sflag's for the checks below in one 176 * "atomic" operation with turning off the astpending flag. 177 * If another AST is triggered while we are handling the 178 * AST's saved in sflag, the astpending flag will be set and 179 * ast() will be called again. 180 */ 181 mtx_lock_spin(&sched_lock); 182 ke = td->td_kse; 183 sticks = ke->ke_sticks; 184 flags = ke->ke_flags; 185 sflag = p->p_sflag; 186 p->p_sflag &= ~(PS_ALRMPEND | PS_NEEDSIGCHK | PS_PROFPEND | PS_XCPU); 187 ke->ke_flags &= ~(KEF_ASTPENDING | KEF_NEEDRESCHED | KEF_OWEUPC); 188 cnt.v_soft++; 189 prticks = 0; 190 if (flags & KEF_OWEUPC && sflag & PS_PROFIL) { 191 prticks = p->p_stats->p_prof.pr_ticks; 192 p->p_stats->p_prof.pr_ticks = 0; 193 } 194 mtx_unlock_spin(&sched_lock); 195 /* 196 * XXXKSE While the fact that we owe a user profiling 197 * tick is stored per KSE in this code, the statistics 198 * themselves are still stored per process. 199 * This should probably change, by which I mean that 200 * possibly the location of both might change. 201 */ 202 203 if (td->td_ucred != p->p_ucred) 204 cred_update_thread(td); 205 if (flags & KEF_OWEUPC && sflag & PS_PROFIL) 206 addupc_task(ke, p->p_stats->p_prof.pr_addr, prticks); 207 if (sflag & PS_ALRMPEND) { 208 PROC_LOCK(p); 209 psignal(p, SIGVTALRM); 210 PROC_UNLOCK(p); 211 } 212#if defined(DEV_NPX) && !defined(SMP) 213 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 214 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags, 215 PCB_NPXTRAP); 216 ucode = npxtrap(); 217 if (ucode != -1) { 218 trapsignal(p, SIGFPE, ucode); 219 } 220 } 221#endif 222 if (sflag & PS_PROFPEND) { 223 PROC_LOCK(p); 224 psignal(p, SIGPROF); 225 PROC_UNLOCK(p); 226 } 227 if (sflag & PS_XCPU) { 228 PROC_LOCK(p); 229 rlim = &p->p_rlimit[RLIMIT_CPU]; 230 if (p->p_runtime.sec >= rlim->rlim_max) 231 killproc(p, "exceeded maximum CPU limit"); 232 else { 233 psignal(p, SIGXCPU); 234 mtx_lock_spin(&sched_lock); 235 if (p->p_cpulimit < rlim->rlim_max) 236 p->p_cpulimit += 5; 237 mtx_unlock_spin(&sched_lock); 238 } 239 PROC_UNLOCK(p); 240 } 241 if (flags & KEF_NEEDRESCHED) { 242 mtx_lock_spin(&sched_lock); 243 sched_prio(td, kg->kg_user_pri); 244 p->p_stats->p_ru.ru_nivcsw++; 245 mi_switch(); 246 mtx_unlock_spin(&sched_lock); 247 } 248 if (sflag & PS_NEEDSIGCHK) { 249 PROC_LOCK(p); 250 while ((sig = cursig(td)) != 0) 251 postsig(sig); 252 PROC_UNLOCK(p); 253 } 254 255 userret(td, framep, sticks); 256#ifdef DIAGNOSTIC 257 cred_free_thread(td); 258#endif 259 mtx_assert(&Giant, MA_NOTOWNED); 260} 261