subr_syscall.c revision 99072
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 99072 2002-06-29 17:26:22Z julian $ 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 <machine/cpu.h> 58#include <machine/pcb.h> 59 60/* 61 * Define the code needed before returning to user mode, for 62 * trap and syscall. 63 * 64 * MPSAFE 65 */ 66void 67userret(td, frame, oticks) 68 struct thread *td; 69 struct trapframe *frame; 70 u_int oticks; 71{ 72 struct proc *p = td->td_proc; 73 struct kse *ke = td->td_kse; 74 struct ksegrp *kg = td->td_ksegrp; 75 76 CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid, 77 p->p_comm); 78#ifdef INVARIANTS 79 /* Check that we called signotify() enough. */ 80 mtx_lock(&Giant); 81 PROC_LOCK(p); 82 mtx_lock_spin(&sched_lock); 83 if (SIGPENDING(p) && ((p->p_sflag & PS_NEEDSIGCHK) == 0 || 84 (ke->ke_flags & KEF_ASTPENDING) == 0)) 85 printf("failed to set signal flags proprly for ast()\n"); 86 mtx_unlock_spin(&sched_lock); 87 PROC_UNLOCK(p); 88 mtx_unlock(&Giant); 89#endif 90 91 /* 92 * XXX we cheat slightly on the locking here to avoid locking in 93 * the usual case. Setting td_priority here is essentially an 94 * incomplete workaround for not setting it properly elsewhere. 95 * Now that some interrupt handlers are threads, not setting it 96 * properly elsewhere can clobber it in the window between setting 97 * it here and returning to user mode, so don't waste time setting 98 * it perfectly here. 99 */ 100 if (td->td_priority != kg->kg_user_pri) { 101 mtx_lock_spin(&sched_lock); 102 td->td_priority = kg->kg_user_pri; 103 mtx_unlock_spin(&sched_lock); 104 } 105 106 /* 107 * We need to check to see if we have to exit or wait due to a 108 * single threading requirement or some other STOP condition. 109 */ 110 PROC_LOCK(p); 111 thread_suspend_check(0); /* Can suspend or kill */ 112 PROC_UNLOCK(p); 113 114 /* 115 * DO special thread processing, e.g. upcall tweaking and such 116 */ 117 if (p->p_flag & P_KSES) { 118 thread_userret(p, kg, ke, 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 = curthread; 147 struct proc *p = td->td_proc; 148 struct kse *ke = td->td_kse; 149 struct ksegrp *kg = td->td_ksegrp; 150 u_int prticks, sticks; 151 int sflag; 152 int flags; 153 int sig; 154#if defined(DEV_NPX) && !defined(SMP) 155 int ucode; 156#endif 157 158 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 159 p->p_comm); 160 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 161#ifdef WITNESS 162 if (witness_list(td)) 163 panic("Returning to user mode with mutex(s) held"); 164#endif 165 mtx_assert(&Giant, MA_NOTOWNED); 166 mtx_assert(&sched_lock, MA_NOTOWNED); 167 prticks = 0; /* XXX: Quiet warning. */ 168 td->td_frame = framep; 169 /* 170 * This updates the p_sflag's for the checks below in one 171 * "atomic" operation with turning off the astpending flag. 172 * If another AST is triggered while we are handling the 173 * AST's saved in sflag, the astpending flag will be set and 174 * ast() will be called again. 175 */ 176 mtx_lock_spin(&sched_lock); 177 sticks = ke->ke_sticks; 178 sflag = p->p_sflag; 179 flags = ke->ke_flags; 180 p->p_sflag &= ~(PS_ALRMPEND | PS_NEEDSIGCHK | PS_PROFPEND); 181 ke->ke_flags &= ~(KEF_ASTPENDING | KEF_NEEDRESCHED | KEF_OWEUPC); 182 cnt.v_soft++; 183 if (flags & KEF_OWEUPC && sflag & PS_PROFIL) { 184 prticks = p->p_stats->p_prof.pr_ticks; 185 p->p_stats->p_prof.pr_ticks = 0; 186 } 187 mtx_unlock_spin(&sched_lock); 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 */ 195 196 if (td->td_ucred != p->p_ucred) 197 cred_update_thread(td); 198 if (flags & KEF_OWEUPC && sflag & PS_PROFIL) 199 addupc_task(ke, p->p_stats->p_prof.pr_addr, prticks); 200 if (sflag & PS_ALRMPEND) { 201 PROC_LOCK(p); 202 psignal(p, SIGVTALRM); 203 PROC_UNLOCK(p); 204 } 205#if defined(DEV_NPX) && !defined(SMP) 206 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 207 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags, 208 PCB_NPXTRAP); 209 ucode = npxtrap(); 210 if (ucode != -1) { 211 trapsignal(p, SIGFPE, ucode); 212 } 213 } 214#endif 215 if (sflag & PS_PROFPEND) { 216 PROC_LOCK(p); 217 psignal(p, SIGPROF); 218 PROC_UNLOCK(p); 219 } 220 if (flags & KEF_NEEDRESCHED) { 221 mtx_lock_spin(&sched_lock); 222 td->td_priority = kg->kg_user_pri; 223 p->p_stats->p_ru.ru_nivcsw++; 224 mi_switch(); 225 mtx_unlock_spin(&sched_lock); 226 } 227 if (sflag & PS_NEEDSIGCHK) { 228 PROC_LOCK(p); 229 while ((sig = cursig(td)) != 0) 230 postsig(sig); 231 PROC_UNLOCK(p); 232 } 233 234 userret(td, framep, sticks); 235 mtx_assert(&Giant, MA_NOTOWNED); 236} 237