subr_syscall.c revision 135573
1326Salm/*- 2326Salm * Copyright (C) 1994, David Greenman 3326Salm * Copyright (c) 1990, 1993 4326Salm * The Regents of the University of California. All rights reserved. 5326Salm * 6326Salm * This code is derived from software contributed to Berkeley by 7326Salm * the University of Utah, and William Jolitz. 8326Salm * 9326Salm * Redistribution and use in source and binary forms, with or without 10326Salm * modification, are permitted provided that the following conditions 11326Salm * are met: 12326Salm * 1. Redistributions of source code must retain the above copyright 13326Salm * notice, this list of conditions and the following disclaimer. 14326Salm * 2. Redistributions in binary form must reproduce the above copyright 15326Salm * notice, this list of conditions and the following disclaimer in the 16326Salm * documentation and/or other materials provided with the distribution. 17326Salm * 3. All advertising materials mentioning features or use of this software 18326Salm * must display the following acknowledgement: 19326Salm * This product includes software developed by the University of 20326Salm * California, Berkeley and its contributors. 21326Salm * 4. Neither the name of the University nor the names of its contributors 22326Salm * may be used to endorse or promote products derived from this software 23326Salm * without specific prior written permission. 24326Salm * 25326Salm * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26326Salm * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27326Salm * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28326Salm * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29326Salm * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30326Salm * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31326Salm * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32326Salm * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33621Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 342941Sbde * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35326Salm * SUCH DAMAGE. 36326Salm * 372941Sbde * from: @(#)trap.c 7.4 (Berkeley) 5/13/91 382941Sbde */ 392941Sbde 40326Salm#include <sys/cdefs.h> 412941Sbde__FBSDID("$FreeBSD: head/sys/kern/subr_trap.c 135573 2004-09-22 15:24:33Z jhb $"); 42326Salm 43326Salm#include "opt_ktrace.h" 442941Sbde#include "opt_mac.h" 452941Sbde#ifdef __i386__ 462941Sbde#include "opt_npx.h" 472941Sbde#endif 482941Sbde 49326Salm#include <sys/param.h> 50326Salm#include <sys/bus.h> 511834Swollman#include <sys/kernel.h> 52326Salm#include <sys/lock.h> 53326Salm#include <sys/mac.h> 54326Salm#include <sys/mutex.h> 552941Sbde#include <sys/proc.h> 562941Sbde#include <sys/ktr.h> 572941Sbde#include <sys/resourcevar.h> 582941Sbde#include <sys/sched.h> 59719Swollman#include <sys/signalvar.h> 60326Salm#include <sys/systm.h> 61326Salm#include <sys/vmmeter.h> 62326Salm#ifdef KTRACE 63338Salm#include <sys/uio.h> 64338Salm#include <sys/ktrace.h> 65326Salm#endif 66338Salm 67326Salm#include <machine/cpu.h> 682941Sbde#include <machine/pcb.h> 692941Sbde 702941Sbde/* 712941Sbde * Define the code needed before returning to user mode, for 722941Sbde * trap and syscall. 732941Sbde * 742941Sbde * MPSAFE 752941Sbde */ 76338Salmvoid 77326Salmuserret(td, frame, oticks) 782941Sbde struct thread *td; 79326Salm struct trapframe *frame; 80326Salm u_int oticks; 812941Sbde{ 82326Salm struct proc *p = td->td_proc; 83326Salm 84338Salm CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid, 85326Salm p->p_comm); 86326Salm#ifdef DIAGNOSTIC 87326Salm /* Check that we called signotify() enough. */ 88326Salm PROC_LOCK(p); 89326Salm mtx_lock_spin(&sched_lock); 90338Salm if (SIGPENDING(td) && ((td->td_flags & TDF_NEEDSIGCHK) == 0 || 91338Salm (td->td_flags & TDF_ASTPENDING) == 0)) 92326Salm printf("failed to set signal flags properly for ast()\n"); 93338Salm mtx_unlock_spin(&sched_lock); 94338Salm PROC_UNLOCK(p); 95326Salm#endif 962941Sbde 972941Sbde /* 982941Sbde * Let the scheduler adjust our priority etc. 992941Sbde */ 100338Salm sched_userret(td); 101338Salm 1022941Sbde /* 103338Salm * We need to check to see if we have to exit or wait due to a 104326Salm * single threading requirement or some other STOP condition. 105326Salm * Don't bother doing all the work if the stop bits are not set 106326Salm * at this time.. If we miss it, we miss it.. no big deal. 107326Salm */ 108326Salm if (P_SHOULDSTOP(p)) { 109326Salm PROC_LOCK(p); 110326Salm thread_suspend_check(0); /* Can suspend or kill */ 111326Salm PROC_UNLOCK(p); 112326Salm } 113326Salm 114326Salm /* 115326Salm * Do special thread processing, e.g. upcall tweaking and such. 116326Salm */ 117326Salm if (p->p_flag & P_SA) 118326Salm thread_userret(td, frame); 119326Salm 120326Salm /* 121326Salm * Charge system time if profiling. 122 */ 123 if (p->p_flag & P_PROFIL) { 124 quad_t ticks; 125 126 mtx_lock_spin(&sched_lock); 127 ticks = td->td_sticks - oticks; 128 mtx_unlock_spin(&sched_lock); 129 addupc_task(td, TRAPF_PC(frame), (u_int)ticks * psratio); 130 } 131} 132 133/* 134 * Process an asynchronous software trap. 135 * This is relatively easy. 136 * This function will return with preemption disabled. 137 */ 138void 139ast(struct trapframe *framep) 140{ 141 struct thread *td; 142 struct proc *p; 143 struct ksegrp *kg; 144 struct rlimit rlim; 145 u_int sticks; 146 int sflag; 147 int flags; 148 int sig; 149#if defined(DEV_NPX) && !defined(SMP) 150 int ucode; 151#endif 152 153 td = curthread; 154 p = td->td_proc; 155 kg = td->td_ksegrp; 156 157 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 158 p->p_comm); 159 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 160 WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode"); 161 mtx_assert(&Giant, MA_NOTOWNED); 162 mtx_assert(&sched_lock, MA_NOTOWNED); 163 td->td_frame = framep; 164 165 if ((p->p_flag & P_SA) && (td->td_mailbox == NULL)) 166 thread_user_enter(td); 167 168 /* 169 * This updates the p_sflag's for the checks below in one 170 * "atomic" operation with turning off the astpending flag. 171 * If another AST is triggered while we are handling the 172 * AST's saved in sflag, the astpending flag will be set and 173 * ast() will be called again. 174 */ 175 mtx_lock_spin(&sched_lock); 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_INTERRUPT); 185 cnt.v_soft++; 186 mtx_unlock_spin(&sched_lock); 187 188 /* 189 * XXXKSE While the fact that we owe a user profiling 190 * tick is stored per KSE in this code, the statistics 191 * themselves are still stored per process. 192 * This should probably change, by which I mean that 193 * possibly the location of both might change. 194 */ 195 if (td->td_ucred != p->p_ucred) 196 cred_update_thread(td); 197 if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) { 198 addupc_task(td, td->td_profil_addr, td->td_profil_ticks); 199 td->td_profil_ticks = 0; 200 td->td_pflags &= ~TDP_OWEUPC; 201 } 202 if (sflag & PS_ALRMPEND) { 203 PROC_LOCK(p); 204 psignal(p, SIGVTALRM); 205 PROC_UNLOCK(p); 206 } 207#if defined(DEV_NPX) && !defined(SMP) 208 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 209 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags, 210 PCB_NPXTRAP); 211 ucode = npxtrap(); 212 if (ucode != -1) { 213 trapsignal(td, SIGFPE, ucode); 214 } 215 } 216#endif 217 if (sflag & PS_PROFPEND) { 218 PROC_LOCK(p); 219 psignal(p, SIGPROF); 220 PROC_UNLOCK(p); 221 } 222 if (sflag & PS_XCPU) { 223 PROC_LOCK(p); 224 lim_rlimit(p, RLIMIT_CPU, &rlim); 225 mtx_lock_spin(&sched_lock); 226 if (p->p_runtime.sec >= rlim.rlim_max) { 227 mtx_unlock_spin(&sched_lock); 228 killproc(p, "exceeded maximum CPU limit"); 229 } else { 230 if (p->p_cpulimit < rlim.rlim_max) 231 p->p_cpulimit += 5; 232 mtx_unlock_spin(&sched_lock); 233 psignal(p, SIGXCPU); 234 } 235 PROC_UNLOCK(p); 236 } 237#ifdef MAC 238 if (sflag & PS_MACPEND) 239 mac_thread_userret(td); 240#endif 241 if (flags & TDF_NEEDRESCHED) { 242#ifdef KTRACE 243 if (KTRPOINT(td, KTR_CSW)) 244 ktrcsw(1, 1); 245#endif 246 mtx_lock_spin(&sched_lock); 247 sched_prio(td, kg->kg_user_pri); 248 mi_switch(SW_INVOL, NULL); 249 mtx_unlock_spin(&sched_lock); 250#ifdef KTRACE 251 if (KTRPOINT(td, KTR_CSW)) 252 ktrcsw(0, 1); 253#endif 254 } 255 if (flags & TDF_NEEDSIGCHK) { 256 PROC_LOCK(p); 257 mtx_lock(&p->p_sigacts->ps_mtx); 258 while ((sig = cursig(td)) != 0) 259 postsig(sig); 260 mtx_unlock(&p->p_sigacts->ps_mtx); 261 PROC_UNLOCK(p); 262 } 263 264 userret(td, framep, sticks); 265 mtx_assert(&Giant, MA_NOTOWNED); 266} 267