subr_syscall.c revision 135573
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: head/sys/kern/subr_trap.c 135573 2004-09-22 15:24:33Z jhb $"); 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 */ 76void 77userret(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 DIAGNOSTIC 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 * 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