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 mtx_lock_spin(&sched_lock); 106 } 107 108 /* 109 * Charge system time if profiling. 110 */ 111 if (p->p_sflag & PS_PROFIL) { 112 quad_t ticks; 113 114 ticks = ke->ke_sticks - oticks; 115 mtx_unlock_spin(&sched_lock); 116 addupc_task(ke, TRAPF_PC(frame), (u_int)ticks * psratio); 117 } else 118 mtx_unlock_spin(&sched_lock); 119 } 120 121 /* 122 * Process an asynchronous software trap. 123 * This is relatively easy. 124 * This function will return with preemption disabled. 125 */ 126 void 127 ast(framep) 128 struct trapframe *framep; 129 { 130 struct thread *td = curthread; 131 struct proc *p = td->td_proc; 132 struct kse *ke = td->td_kse; 133 u_int prticks, sticks; 134 critical_t s; 135 int sflag; 136 int flags; 137 #if defined(DEV_NPX) && !defined(SMP) 138 int ucode; 139 #endif 140 141 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 142 KASSERT(td->td_ucred == NULL, ("leaked ucred")); 143 #ifdef WITNESS 144 if (witness_list(td)) 145 panic("Returning to user mode with mutex(s) held"); 146 #endif 147 mtx_assert(&Giant, MA_NOTOWNED); 148 prticks = 0; /* XXX: Quiet warning. */ 149 s = cpu_critical_enter(); 150 while ((ke->ke_flags & (KEF_ASTPENDING | KEF_NEEDRESCHED)) != 0) { 151 cpu_critical_exit(s); 152 td->td_frame = framep; 153 /* 154 * This updates the p_sflag's for the checks below in one 155 * "atomic" operation with turning off the astpending flag. 156 * If another AST is triggered while we are handling the 157 * AST's saved in sflag, the astpending flag will be set and 158 * we will loop again. 159 */ 160 mtx_lock_spin(&sched_lock); 161 sticks = ke->ke_sticks; 162 sflag = p->p_sflag; 163 flags = ke->ke_flags; 164 p->p_sflag &= ~(PS_PROFPEND | PS_ALRMPEND); 165 ke->ke_flags &= ~(KEF_OWEUPC | KEF_ASTPENDING); 166 cnt.v_soft++; 167 if (flags & KEF_OWEUPC && sflag & PS_PROFIL) { 168 prticks = p->p_stats->p_prof.pr_ticks; 169 p->p_stats->p_prof.pr_ticks = 0; 170 } 171 mtx_unlock_spin(&sched_lock); 172 PROC_LOCK(p); 173 td->td_ucred = crhold(p->p_ucred); 174 PROC_UNLOCK(p); 175 if (flags & KEF_OWEUPC && sflag & PS_PROFIL) 176 addupc_task(ke, p->p_stats->p_prof.pr_addr, prticks); 177 if (sflag & PS_ALRMPEND) { 178 PROC_LOCK(p); 179 psignal(p, SIGVTALRM); 180 PROC_UNLOCK(p); 181 } 182 #if defined(DEV_NPX) && !defined(SMP) 183 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 184 atomic_clear_char(&PCPU_GET(curpcb)->pcb_flags, 185 PCB_NPXTRAP); 186 ucode = npxtrap(); 187 if (ucode != -1) { 188 trapsignal(p, SIGFPE, ucode); 189 } 190 } 191 #endif 192 if (sflag & PS_PROFPEND) { 193 PROC_LOCK(p); 194 psignal(p, SIGPROF); 195 PROC_UNLOCK(p); 196 } 197 198 userret(td, framep, sticks); 199 mtx_lock(&Giant); 200 crfree(td->td_ucred); 201 mtx_unlock(&Giant); 202 td->td_ucred = NULL; 203 s = cpu_critical_enter(); 204 } 205 mtx_assert(&Giant, MA_NOTOWNED); 206 /* 207 * We need to keep interrupts disabled so that if any further AST's 208 * come in, the interrupt they come in on will be delayed until we 209 * finish returning to userland. We assume that the return to userland 210 * will perform the equivalent of cpu_critical_exit(). 211 */ 212 } 213