subr_syscall.c revision 82585
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 82585 2001-08-30 18:50:57Z dillon $ 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(p, frame, oticks) 66 struct proc *p; 67 struct trapframe *frame; 68 u_int oticks; 69{ 70 int sig; 71 72 mtx_lock(&Giant); 73 PROC_LOCK(p); 74 while ((sig = CURSIG(p)) != 0) 75 postsig(sig); 76 PROC_UNLOCK(p); 77 mtx_unlock(&Giant); 78 79 mtx_lock_spin(&sched_lock); 80 p->p_pri.pri_level = p->p_pri.pri_user; 81 if (p->p_sflag & PS_NEEDRESCHED) { 82 /* 83 * Since we are curproc, a clock interrupt could 84 * change our priority without changing run queues 85 * (the running process is not kept on a run queue). 86 * If this happened after we setrunqueue ourselves but 87 * before we switch()'ed, we might not be on the queue 88 * indicated by our priority. 89 */ 90 DROP_GIANT_NOSWITCH(); 91 setrunqueue(p); 92 p->p_stats->p_ru.ru_nivcsw++; 93 mi_switch(); 94 mtx_unlock_spin(&sched_lock); 95 PICKUP_GIANT(); 96 mtx_lock(&Giant); 97 PROC_LOCK(p); 98 while ((sig = CURSIG(p)) != 0) 99 postsig(sig); 100 mtx_unlock(&Giant); 101 PROC_UNLOCK(p); 102 } else 103 mtx_unlock_spin(&sched_lock); 104 105 /* 106 * Charge system time if profiling. 107 */ 108 if (p->p_sflag & PS_PROFIL) 109 addupc_task(p, TRAPF_PC(frame), 110 ((u_int)p->p_sticks - oticks) * psratio); 111} 112 113/* 114 * Process an asynchronous software trap. 115 * This is relatively easy. 116 * This function will return with preemption disabled. 117 */ 118void 119ast(framep) 120 struct trapframe *framep; 121{ 122 struct proc *p = CURPROC; 123 u_int prticks, sticks; 124 critical_t s; 125 int sflag; 126#if defined(DEV_NPX) && !defined(SMP) 127 int ucode; 128#endif 129 130 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 131#ifdef WITNESS 132 if (witness_list(p)) 133 panic("Returning to user mode with mutex(s) held"); 134#endif 135 mtx_assert(&Giant, MA_NOTOWNED); 136 s = critical_enter(); 137 while ((p->p_sflag & (PS_ASTPENDING | PS_NEEDRESCHED)) != 0) { 138 critical_exit(s); 139 p->p_frame = framep; 140 /* 141 * This updates the p_sflag's for the checks below in one 142 * "atomic" operation with turning off the astpending flag. 143 * If another AST is triggered while we are handling the 144 * AST's saved in sflag, the astpending flag will be set and 145 * we will loop again. 146 */ 147 mtx_lock_spin(&sched_lock); 148 sticks = p->p_sticks; 149 sflag = p->p_sflag; 150 p->p_sflag &= ~(PS_OWEUPC | PS_ALRMPEND | PS_PROFPEND | 151 PS_ASTPENDING); 152 cnt.v_soft++; 153 if (sflag & PS_OWEUPC) { 154 prticks = p->p_stats->p_prof.pr_ticks; 155 p->p_stats->p_prof.pr_ticks = 0; 156 mtx_unlock_spin(&sched_lock); 157 addupc_task(p, p->p_stats->p_prof.pr_addr, prticks); 158 } else 159 mtx_unlock_spin(&sched_lock); 160 if (sflag & PS_ALRMPEND) { 161 PROC_LOCK(p); 162 psignal(p, SIGVTALRM); 163 PROC_UNLOCK(p); 164 } 165#if defined(DEV_NPX) && !defined(SMP) 166 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 167 atomic_clear_char(&PCPU_GET(curpcb)->pcb_flags, 168 PCB_NPXTRAP); 169 ucode = npxtrap(); 170 if (ucode != -1) { 171 trapsignal(p, SIGFPE, ucode); 172 } 173 } 174#endif 175 if (sflag & PS_PROFPEND) { 176 PROC_LOCK(p); 177 psignal(p, SIGPROF); 178 PROC_UNLOCK(p); 179 } 180 181 userret(p, framep, sticks); 182 s = critical_enter(); 183 } 184 mtx_assert(&Giant, MA_NOTOWNED); 185 /* 186 * We need to keep interrupts disabled so that if any further AST's 187 * come in, the interrupt they come in on will be delayed until we 188 * finish returning to userland. We assume that the return to userland 189 * will perform the equivalent of critical_exit(). 190 */ 191} 192