subr_syscall.c revision 104297
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 104297 2002-10-01 14:16:50Z jhb $ 39 */ 40 41#ifdef __i386__ 42#include "opt_npx.h" 43#endif 44 45#include <sys/param.h> 46#include <sys/bus.h> 47#include <sys/kernel.h> 48#include <sys/lock.h> 49#include <sys/mutex.h> 50#include <sys/proc.h> 51#include <sys/kse.h> 52#include <sys/ktr.h> 53#include <sys/resourcevar.h> 54#include <sys/signalvar.h> 55#include <sys/systm.h> 56#include <sys/vmmeter.h> 57#include <sys/malloc.h> 58#include <sys/ksiginfo.h> 59#include <machine/cpu.h> 60#include <machine/pcb.h> 61 62/* 63 * Define the code needed before returning to user mode, for 64 * trap and syscall. 65 * 66 * MPSAFE 67 */ 68void 69userret(td, frame, oticks) 70 struct thread *td; 71 struct trapframe *frame; 72 u_int oticks; 73{ 74 struct proc *p = td->td_proc; 75 struct kse *ke = td->td_kse; 76 struct ksegrp *kg = td->td_ksegrp; 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 (signal_pending(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 /* 94 * XXX we cheat slightly on the locking here to avoid locking in 95 * the usual case. Setting td_priority here is essentially an 96 * incomplete workaround for not setting it properly elsewhere. 97 * Now that some interrupt handlers are threads, not setting it 98 * properly elsewhere can clobber it in the window between setting 99 * it here and returning to user mode, so don't waste time setting 100 * it perfectly here. 101 */ 102 if (td->td_priority != kg->kg_user_pri) { 103 mtx_lock_spin(&sched_lock); 104 td->td_priority = kg->kg_user_pri; 105 mtx_unlock_spin(&sched_lock); 106 } 107 108 /* 109 * We need to check to see if we have to exit or wait due to a 110 * single threading requirement or some other STOP condition. 111 * Don't bother doing all the work if the stop bits are not set 112 * at this time.. If we miss it, we miss it.. no big deal. 113 */ 114 if (P_SHOULDSTOP(p)) { 115 PROC_LOCK(p); 116 thread_suspend_check(0); /* Can suspend or kill */ 117 PROC_UNLOCK(p); 118 } 119 120 /* 121 * DO special thread processing, e.g. upcall tweaking and such 122 */ 123 if (p->p_flag & P_KSES) { 124 thread_userret(td, frame); 125 /* printf("KSE thread returned"); */ 126 } 127 128 /* 129 * Charge system time if profiling. 130 * 131 * XXX should move PS_PROFIL to a place that can obviously be 132 * accessed safely without sched_lock. 133 */ 134 if (p->p_sflag & PS_PROFIL) { 135 quad_t ticks; 136 137 mtx_lock_spin(&sched_lock); 138 ticks = ke->ke_sticks - oticks; 139 mtx_unlock_spin(&sched_lock); 140 addupc_task(ke, TRAPF_PC(frame), (u_int)ticks * psratio); 141 } 142} 143 144/* 145 * Process an asynchronous software trap. 146 * This is relatively easy. 147 * This function will return with preemption disabled. 148 */ 149void 150ast(struct trapframe *framep) 151{ 152 struct thread *td; 153 struct proc *p; 154 struct kse *ke; 155 struct ksegrp *kg; 156 struct rlimit *rlim; 157 u_int prticks, sticks; 158 int sflag; 159 int flags; 160 int sig; 161#if defined(DEV_NPX) && !defined(SMP) 162 int ucode; 163#endif 164 165 td = curthread; 166 p = td->td_proc; 167 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 168 p->p_comm); 169 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 170#ifdef WITNESS 171 if (witness_list(td)) 172 panic("Returning to user mode with mutex(s) held"); 173#endif 174 mtx_assert(&Giant, MA_NOTOWNED); 175 mtx_assert(&sched_lock, MA_NOTOWNED); 176 kg = td->td_ksegrp; 177 td->td_frame = framep; 178 179 /* 180 * This updates the p_sflag's for the checks below in one 181 * "atomic" operation with turning off the astpending flag. 182 * If another AST is triggered while we are handling the 183 * AST's saved in sflag, the astpending flag will be set and 184 * ast() will be called again. 185 */ 186 mtx_lock_spin(&sched_lock); 187 ke = td->td_kse; 188 sticks = ke->ke_sticks; 189 flags = ke->ke_flags; 190 sflag = p->p_sflag; 191 p->p_sflag &= ~(PS_ALRMPEND | PS_NEEDSIGCHK | PS_PROFPEND | PS_XCPU); 192 ke->ke_flags &= ~(KEF_ASTPENDING | KEF_NEEDRESCHED | KEF_OWEUPC); 193 cnt.v_soft++; 194 prticks = 0; 195 if (flags & KEF_OWEUPC && sflag & PS_PROFIL) { 196 prticks = p->p_stats->p_prof.pr_ticks; 197 p->p_stats->p_prof.pr_ticks = 0; 198 } 199 mtx_unlock_spin(&sched_lock); 200 /* 201 * XXXKSE While the fact that we owe a user profiling 202 * tick is stored per KSE in this code, the statistics 203 * themselves are still stored per process. 204 * This should probably change, by which I mean that 205 * possibly the location of both might change. 206 */ 207 208 if (td->td_ucred != p->p_ucred) 209 cred_update_thread(td); 210 if (flags & KEF_OWEUPC && sflag & PS_PROFIL) 211 addupc_task(ke, p->p_stats->p_prof.pr_addr, prticks); 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 if (rlim->rlim_cur < rlim->rlim_max) 240 /* XXX: we should make a private copy. */ 241 rlim->rlim_cur += 5; 242 } 243 PROC_UNLOCK(p); 244 } 245 if (flags & KEF_NEEDRESCHED) { 246 mtx_lock_spin(&sched_lock); 247 td->td_priority = kg->kg_user_pri; 248 p->p_stats->p_ru.ru_nivcsw++; 249 mi_switch(); 250 mtx_unlock_spin(&sched_lock); 251 } 252 if (sflag & PS_NEEDSIGCHK) { 253 PROC_LOCK(p); 254 while ((sig = cursig(td)) != 0) 255 postsig(sig); 256 PROC_UNLOCK(p); 257 } 258 259 userret(td, framep, sticks); 260#ifdef DIAGNOSTIC 261 cred_free_thread(td); 262#endif 263 mtx_assert(&Giant, MA_NOTOWNED); 264} 265