subr_syscall.c revision 93793
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 93793 2002-04-04 17:49:48Z bde $ 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/resourcevar.h> 52#include <sys/signalvar.h> 53#include <sys/systm.h> 54#include <sys/vmmeter.h> 55#include <machine/cpu.h> 56#include <machine/pcb.h> 57 58/* 59 * Define the code needed before returning to user mode, for 60 * trap and syscall. 61 * 62 * MPSAFE 63 */ 64void 65userret(td, frame, oticks) 66 struct thread *td; 67 struct trapframe *frame; 68 u_int oticks; 69{ 70 struct proc *p = td->td_proc; 71 struct kse *ke = td->td_kse; 72 struct ksegrp *kg = td->td_ksegrp; 73 74#ifdef INVARIANTS 75 /* Check that we called signotify() enough. */ 76 mtx_lock(&Giant); 77 PROC_LOCK(p); 78 mtx_lock_spin(&sched_lock); 79 if (SIGPENDING(p) && ((p->p_sflag & PS_NEEDSIGCHK) == 0 || 80 (p->p_kse.ke_flags & KEF_ASTPENDING) == 0)) 81 printf("failed to set signal flags proprly for ast()\n"); 82 mtx_unlock_spin(&sched_lock); 83 PROC_UNLOCK(p); 84 mtx_unlock(&Giant); 85#endif 86 87 /* 88 * XXX we cheat slightly on the locking here to avoid locking in 89 * the usual case. Setting td_priority here is essentially an 90 * incomplete workaround for not setting it properly elsewhere. 91 * Now that some interrupt handlers are threads, not setting it 92 * properly elsewhere can clobber it in the window between setting 93 * it here and returning to user mode, so don't waste time setting 94 * it perfectly here. 95 */ 96 if (td->td_priority != kg->kg_user_pri) { 97 mtx_lock_spin(&sched_lock); 98 td->td_priority = kg->kg_user_pri; 99 mtx_unlock_spin(&sched_lock); 100 } 101 102 /* 103 * Charge system time if profiling. 104 * 105 * XXX should move PS_PROFIL to a place that can obviously be 106 * accessed safely without sched_lock. 107 */ 108 if (p->p_sflag & PS_PROFIL) { 109 quad_t ticks; 110 111 mtx_lock_spin(&sched_lock); 112 ticks = ke->ke_sticks - oticks; 113 mtx_unlock_spin(&sched_lock); 114 addupc_task(ke, TRAPF_PC(frame), (u_int)ticks * psratio); 115 } 116} 117 118/* 119 * Process an asynchronous software trap. 120 * This is relatively easy. 121 * This function will return with preemption disabled. 122 */ 123void 124ast(framep) 125 struct trapframe *framep; 126{ 127 struct thread *td = curthread; 128 struct proc *p = td->td_proc; 129 struct kse *ke = td->td_kse; 130 struct ksegrp *kg = td->td_ksegrp; 131 u_int prticks, sticks; 132 int sflag; 133 int flags; 134 int sig; 135#if defined(DEV_NPX) && !defined(SMP) 136 int ucode; 137#endif 138 139 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 140#ifdef WITNESS 141 if (witness_list(td)) 142 panic("Returning to user mode with mutex(s) held"); 143#endif 144 mtx_assert(&Giant, MA_NOTOWNED); 145 mtx_assert(&sched_lock, MA_NOTOWNED); 146 prticks = 0; /* XXX: Quiet warning. */ 147 td->td_frame = framep; 148 /* 149 * This updates the p_sflag's for the checks below in one 150 * "atomic" operation with turning off the astpending flag. 151 * If another AST is triggered while we are handling the 152 * AST's saved in sflag, the astpending flag will be set and 153 * ast() will be called again. 154 */ 155 mtx_lock_spin(&sched_lock); 156 sticks = ke->ke_sticks; 157 sflag = p->p_sflag; 158 flags = ke->ke_flags; 159 p->p_sflag &= ~(PS_ALRMPEND | PS_NEEDSIGCHK | PS_PROFPEND); 160 ke->ke_flags &= ~(KEF_ASTPENDING | KEF_NEEDRESCHED | KEF_OWEUPC); 161 cnt.v_soft++; 162 if (flags & KEF_OWEUPC && sflag & PS_PROFIL) { 163 prticks = p->p_stats->p_prof.pr_ticks; 164 p->p_stats->p_prof.pr_ticks = 0; 165 } 166 mtx_unlock_spin(&sched_lock); 167 168 if (td->td_ucred != p->p_ucred) 169 cred_update_thread(td); 170 if (flags & KEF_OWEUPC && sflag & PS_PROFIL) 171 addupc_task(ke, p->p_stats->p_prof.pr_addr, prticks); 172 if (sflag & PS_ALRMPEND) { 173 PROC_LOCK(p); 174 psignal(p, SIGVTALRM); 175 PROC_UNLOCK(p); 176 } 177#if defined(DEV_NPX) && !defined(SMP) 178 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 179 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags, 180 PCB_NPXTRAP); 181 ucode = npxtrap(); 182 if (ucode != -1) { 183 trapsignal(p, SIGFPE, ucode); 184 } 185 } 186#endif 187 if (sflag & PS_PROFPEND) { 188 PROC_LOCK(p); 189 psignal(p, SIGPROF); 190 PROC_UNLOCK(p); 191 } 192 if (flags & KEF_NEEDRESCHED) { 193 mtx_lock_spin(&sched_lock); 194 td->td_priority = kg->kg_user_pri; 195 setrunqueue(td); 196 p->p_stats->p_ru.ru_nivcsw++; 197 mi_switch(); 198 mtx_unlock_spin(&sched_lock); 199 } 200 if (sflag & PS_NEEDSIGCHK) { 201 mtx_lock(&Giant); 202 PROC_LOCK(p); 203 while ((sig = CURSIG(p)) != 0) 204 postsig(sig); 205 PROC_UNLOCK(p); 206 mtx_unlock(&Giant); 207 } 208 209 userret(td, framep, sticks); 210#ifdef DIAGNOSTIC 211 cred_free_thread(td); 212#endif 213 mtx_assert(&Giant, MA_NOTOWNED); 214} 215