subr_syscall.c revision 109877
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 109877 2003-01-26 11:41:35Z davidxu $ 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#ifdef INVARIANTS 77 struct kse *ke; 78#endif 79 80 CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid, 81 p->p_comm); 82#ifdef INVARIANTS 83 /* 84 * Check that we called signotify() enough. 85 * XXXKSE this checking is bogus for threaded program, 86 */ 87 mtx_lock(&Giant); 88 PROC_LOCK(p); 89 mtx_lock_spin(&sched_lock); 90 ke = td->td_kse; 91 if (SIGPENDING(p) && ((p->p_sflag & PS_NEEDSIGCHK) == 0 || 92 (td->td_kse->ke_flags & KEF_ASTPENDING) == 0)) 93 printf("failed to set signal flags properly for ast()\n"); 94 mtx_unlock_spin(&sched_lock); 95 PROC_UNLOCK(p); 96 mtx_unlock(&Giant); 97#endif 98 99 /* 100 * Let the scheduler adjust our priority etc. 101 */ 102 sched_userret(td); 103 104 /* 105 * Charge system time if profiling. 106 * 107 * XXX should move PS_PROFIL to a place that can obviously be 108 * accessed safely without sched_lock. 109 */ 110 111 if (p->p_sflag & PS_PROFIL) { 112 ticks = td->td_sticks - oticks; 113 addupc_task(td, TRAPF_PC(frame), (u_int)ticks * psratio); 114 } 115 116 /* 117 * We need to check to see if we have to exit or wait due to a 118 * single threading requirement or some other STOP condition. 119 * Don't bother doing all the work if the stop bits are not set 120 * at this time.. If we miss it, we miss it.. no big deal. 121 */ 122 if (P_SHOULDSTOP(p)) { 123 PROC_LOCK(p); 124 thread_suspend_check(0); /* Can suspend or kill */ 125 PROC_UNLOCK(p); 126 } 127 128 /* 129 * Do special thread processing, e.g. upcall tweaking and such. 130 */ 131 if (p->p_flag & P_KSES) { 132 thread_userret(td, frame); 133 } 134} 135 136/* 137 * Process an asynchronous software trap. 138 * This is relatively easy. 139 * This function will return with preemption disabled. 140 */ 141void 142ast(struct trapframe *framep) 143{ 144 struct thread *td; 145 struct proc *p; 146 struct kse *ke; 147 struct ksegrp *kg; 148 struct rlimit *rlim; 149 u_int prticks, sticks; 150 int sflag; 151 int flags; 152 int tflags; 153 int sig; 154#if defined(DEV_NPX) && !defined(SMP) 155 int ucode; 156#endif 157 158 td = curthread; 159 p = td->td_proc; 160 kg = td->td_ksegrp; 161 162 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 163 p->p_comm); 164 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 165#ifdef WITNESS 166 if (witness_list(td)) 167 panic("Returning to user mode with mutex(s) held"); 168#endif 169 mtx_assert(&Giant, MA_NOTOWNED); 170 mtx_assert(&sched_lock, MA_NOTOWNED); 171 td->td_frame = framep; 172 173 /* 174 * This updates the p_sflag's for the checks below in one 175 * "atomic" operation with turning off the astpending flag. 176 * If another AST is triggered while we are handling the 177 * AST's saved in sflag, the astpending flag will be set and 178 * ast() will be called again. 179 */ 180 mtx_lock_spin(&sched_lock); 181 ke = td->td_kse; 182 sticks = td->td_sticks; 183 tflags = td->td_flags; 184 flags = ke->ke_flags; 185 sflag = p->p_sflag; 186 p->p_sflag &= ~(PS_ALRMPEND | PS_NEEDSIGCHK | PS_PROFPEND | PS_XCPU); 187#ifdef MAC 188 p->p_sflag &= ~PS_MACPEND; 189#endif 190 ke->ke_flags &= ~(KEF_ASTPENDING | KEF_NEEDRESCHED); 191 td->td_flags &= ~(TDF_ASTPENDING | TDF_OWEUPC); 192 cnt.v_soft++; 193 prticks = 0; 194 if (tflags & TDF_OWEUPC && sflag & PS_PROFIL) { 195 prticks = td->td_prticks; 196 td->td_prticks = 0; 197 } 198 mtx_unlock_spin(&sched_lock); 199 /* 200 * XXXKSE While the fact that we owe a user profiling 201 * tick is stored per KSE in this code, the statistics 202 * themselves are still stored per process. 203 * This should probably change, by which I mean that 204 * possibly the location of both might change. 205 */ 206 207 if (td->td_ucred != p->p_ucred) 208 cred_update_thread(td); 209 if (tflags & TDF_OWEUPC && sflag & PS_PROFIL) { 210 addupc_task(td, td->td_praddr, prticks); 211 } 212 if (sflag & PS_ALRMPEND) { 213 PROC_LOCK(p); 214 psignal(p, SIGVTALRM); 215 PROC_UNLOCK(p); 216 } 217#if defined(DEV_NPX) && !defined(SMP) 218 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 219 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags, 220 PCB_NPXTRAP); 221 ucode = npxtrap(); 222 if (ucode != -1) { 223 trapsignal(p, SIGFPE, ucode); 224 } 225 } 226#endif 227 if (sflag & PS_PROFPEND) { 228 PROC_LOCK(p); 229 psignal(p, SIGPROF); 230 PROC_UNLOCK(p); 231 } 232 if (sflag & PS_XCPU) { 233 PROC_LOCK(p); 234 rlim = &p->p_rlimit[RLIMIT_CPU]; 235 if (p->p_runtime.sec >= rlim->rlim_max) 236 killproc(p, "exceeded maximum CPU limit"); 237 else { 238 psignal(p, SIGXCPU); 239 mtx_lock_spin(&sched_lock); 240 if (p->p_cpulimit < rlim->rlim_max) 241 p->p_cpulimit += 5; 242 mtx_unlock_spin(&sched_lock); 243 } 244 PROC_UNLOCK(p); 245 } 246#ifdef MAC 247 if (sflag & PS_MACPEND) 248 mac_thread_userret(td); 249#endif 250 if (flags & KEF_NEEDRESCHED) { 251 mtx_lock_spin(&sched_lock); 252 sched_prio(td, kg->kg_user_pri); 253 p->p_stats->p_ru.ru_nivcsw++; 254 mi_switch(); 255 mtx_unlock_spin(&sched_lock); 256 } 257 if (sflag & PS_NEEDSIGCHK) { 258 PROC_LOCK(p); 259 while ((sig = cursig(td)) != 0) 260 postsig(sig); 261 PROC_UNLOCK(p); 262 } 263 264 userret(td, framep, sticks); 265#ifdef DIAGNOSTIC 266 cred_free_thread(td); 267#endif 268 mtx_assert(&Giant, MA_NOTOWNED); 269} 270