subr_syscall.c revision 81493
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 81493 2001-08-10 22:53:32Z 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/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 */ 62void 63userret(p, frame, oticks) 64 struct proc *p; 65 struct trapframe *frame; 66 u_int oticks; 67{ 68 int sig; 69 70 mtx_lock(&Giant); 71 PROC_LOCK(p); 72 while ((sig = CURSIG(p)) != 0) 73 postsig(sig); 74 mtx_unlock(&Giant); 75 PROC_UNLOCK(p); 76 77 mtx_lock_spin(&sched_lock); 78 p->p_pri.pri_level = p->p_pri.pri_user; 79 if (p->p_sflag & PS_NEEDRESCHED) { 80 /* 81 * Since we are curproc, a clock interrupt could 82 * change our priority without changing run queues 83 * (the running process is not kept on a run queue). 84 * If this happened after we setrunqueue ourselves but 85 * before we switch()'ed, we might not be on the queue 86 * indicated by our priority. 87 */ 88 DROP_GIANT_NOSWITCH(); 89 setrunqueue(p); 90 p->p_stats->p_ru.ru_nivcsw++; 91 mi_switch(); 92 mtx_unlock_spin(&sched_lock); 93 PICKUP_GIANT(); 94 mtx_lock(&Giant); 95 PROC_LOCK(p); 96 while ((sig = CURSIG(p)) != 0) 97 postsig(sig); 98 mtx_unlock(&Giant); 99 PROC_UNLOCK(p); 100 } else 101 mtx_unlock_spin(&sched_lock); 102 103 /* 104 * Charge system time if profiling. 105 */ 106 if (p->p_sflag & PS_PROFIL) 107 addupc_task(p, TRAPF_PC(frame), 108 ((u_int)p->p_sticks - oticks) * psratio); 109} 110 111/* 112 * Process an asynchronous software trap. 113 * This is relatively easy. 114 * This function will return with preemption disabled. 115 */ 116void 117ast(framep) 118 struct trapframe *framep; 119{ 120 struct proc *p = CURPROC; 121 u_int prticks, sticks; 122 critical_t s; 123 int sflag; 124#if defined(DEV_NPX) && !defined(SMP) 125 int ucode; 126#endif 127 128 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 129#ifdef WITNESS 130 if (witness_list(p)) 131 panic("Returning to user mode with mutex(s) held"); 132#endif 133 mtx_assert(&Giant, MA_NOTOWNED); 134 s = critical_enter(); 135 while ((p->p_sflag & (PS_ASTPENDING | PS_NEEDRESCHED)) != 0) { 136 critical_exit(s); 137 p->p_frame = framep; 138 /* 139 * This updates the p_sflag's for the checks below in one 140 * "atomic" operation with turning off the astpending flag. 141 * If another AST is triggered while we are handling the 142 * AST's saved in sflag, the astpending flag will be set and 143 * we will loop again. 144 */ 145 mtx_lock_spin(&sched_lock); 146 sticks = p->p_sticks; 147 sflag = p->p_sflag; 148 p->p_sflag &= ~(PS_OWEUPC | PS_ALRMPEND | PS_PROFPEND | 149 PS_ASTPENDING); 150 cnt.v_soft++; 151 if (sflag & PS_OWEUPC) { 152 prticks = p->p_stats->p_prof.pr_ticks; 153 p->p_stats->p_prof.pr_ticks = 0; 154 mtx_unlock_spin(&sched_lock); 155 addupc_task(p, p->p_stats->p_prof.pr_addr, prticks); 156 } else 157 mtx_unlock_spin(&sched_lock); 158 if (sflag & PS_ALRMPEND) { 159 PROC_LOCK(p); 160 psignal(p, SIGVTALRM); 161 PROC_UNLOCK(p); 162 } 163#if defined(DEV_NPX) && !defined(SMP) 164 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 165 atomic_clear_char(&PCPU_GET(curpcb)->pcb_flags, 166 PCB_NPXTRAP); 167 ucode = npxtrap(); 168 if (ucode != -1) { 169 mtx_lock(&Giant); 170 trapsignal(p, SIGFPE, ucode); 171 } 172 } 173#endif 174 if (sflag & PS_PROFPEND) { 175 PROC_LOCK(p); 176 psignal(p, SIGPROF); 177 PROC_UNLOCK(p); 178 } 179 180 userret(p, framep, sticks); 181 if (mtx_owned(&Giant)) 182 mtx_unlock(&Giant); 183 s = critical_enter(); 184 } 185 mtx_assert(&Giant, MA_NOTOWNED); 186 /* 187 * We need to keep interrupts disabled so that if any further AST's 188 * come in, the interrupt they come in on will be delayed until we 189 * finish returning to userland. We assume that the return to userland 190 * will perform the equivalent of critical_exit(). 191 */ 192} 193