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 * $FreeBSD$ 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 */ 64 void 65 userret(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 int sig; 74 75 mtx_lock(&Giant); 76 PROC_LOCK(p); 77 while ((sig = CURSIG(p)) != 0) 78 postsig(sig); 79 PROC_UNLOCK(p); 80 mtx_unlock(&Giant); 81 82 mtx_lock_spin(&sched_lock); 83 kg->kg_pri.pri_level = kg->kg_pri.pri_user; 84 if (ke->ke_flags & KEF_NEEDRESCHED) { 85 /* 86 * Since we are curproc, a clock interrupt could 87 * change our priority without changing run queues 88 * (the running process is not kept on a run queue). 89 * If this happened after we setrunqueue ourselves but 90 * before we switch()'ed, we might not be on the queue 91 * indicated by our priority. 92 */ 93 DROP_GIANT_NOSWITCH(); 94 setrunqueue(td); 95 p->p_stats->p_ru.ru_nivcsw++; 96 mi_switch(); 97 mtx_unlock_spin(&sched_lock); 98 PICKUP_GIANT(); 99 mtx_lock(&Giant); 100 PROC_LOCK(p); 101 while ((sig = CURSIG(p)) != 0) 102 postsig(sig); 103 mtx_unlock(&Giant); 104 PROC_UNLOCK(p); 105 } else 106 mtx_unlock_spin(&sched_lock); 107 108 /* 109 * Charge system time if profiling. 110 */ 111 if (p->p_sflag & PS_PROFIL) { 112 addupc_task(ke, TRAPF_PC(frame), 113 (u_int)(ke->ke_sticks - oticks) * psratio); 114 } 115 } 116 117 /* 118 * Process an asynchronous software trap. 119 * This is relatively easy. 120 * This function will return with preemption disabled. 121 */ 122 void 123 ast(framep) 124 struct trapframe *framep; 125 { 126 struct thread *td = curthread; 127 struct proc *p = td->td_proc; 128 struct kse *ke = td->td_kse; 129 u_int prticks, sticks; 130 critical_t s; 131 int sflag; 132 int flags; 133 #if defined(DEV_NPX) && !defined(SMP) 134 int ucode; 135 #endif 136 137 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 138 KASSERT(td->td_ucred == NULL, ("leaked ucred")); 139 #ifdef WITNESS 140 if (witness_list(td)) 141 panic("Returning to user mode with mutex(s) held"); 142 #endif 143 mtx_assert(&Giant, MA_NOTOWNED); 144 s = critical_enter(); 145 while ((ke->ke_flags & (KEF_ASTPENDING | KEF_NEEDRESCHED)) != 0) { 146 critical_exit(s); 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 * we will loop 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_PROFPEND | PS_ALRMPEND); 160 ke->ke_flags &= ~(KEF_OWEUPC | KEF_ASTPENDING); 161 cnt.v_soft++; 162 if (flags & KEF_OWEUPC) { 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 PROC_LOCK(p); 168 td->td_ucred = crhold(p->p_ucred); 169 PROC_UNLOCK(p); 170 if (flags & KEF_OWEUPC) 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_char(&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 } 192 193 userret(td, framep, sticks); 194 mtx_lock(&Giant); 195 crfree(td->td_ucred); 196 mtx_unlock(&Giant); 197 td->td_ucred = NULL; 198 s = critical_enter(); 199 } 200 mtx_assert(&Giant, MA_NOTOWNED); 201 /* 202 * We need to keep interrupts disabled so that if any further AST's 203 * come in, the interrupt they come in on will be delayed until we 204 * finish returning to userland. We assume that the return to userland 205 * will perform the equivalent of critical_exit(). 206 */ 207 } 208