subr_syscall.c revision 99714
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 99714 2002-07-10 06:40:22Z julian $ 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/kse.h> 52#include <sys/ktr.h> 53#include <sys/resourcevar.h> 54#include <sys/signalvar.h> 55#include <sys/systm.h> 56#include <sys/vmmeter.h> 57#include <machine/cpu.h> 58#include <machine/pcb.h> 59 60/* 61 * Define the code needed before returning to user mode, for 62 * trap and syscall. 63 * 64 * MPSAFE 65 */ 66void 67userret(td, frame, oticks) 68 struct thread *td; 69 struct trapframe *frame; 70 u_int oticks; 71{ 72 struct proc *p = td->td_proc; 73 struct kse *ke = td->td_kse; 74 struct ksegrp *kg = td->td_ksegrp; 75 76 CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid, 77 p->p_comm); 78#ifdef INVARIANTS 79 /* Check that we called signotify() enough. */ 80 mtx_lock(&Giant); 81 PROC_LOCK(p); 82 mtx_lock_spin(&sched_lock); 83 if (SIGPENDING(p) && ((p->p_sflag & PS_NEEDSIGCHK) == 0 || 84 (ke->ke_flags & KEF_ASTPENDING) == 0)) 85 printf("failed to set signal flags proprly for ast()\n"); 86 mtx_unlock_spin(&sched_lock); 87 PROC_UNLOCK(p); 88 mtx_unlock(&Giant); 89#endif 90 91 /* 92 * XXX we cheat slightly on the locking here to avoid locking in 93 * the usual case. Setting td_priority here is essentially an 94 * incomplete workaround for not setting it properly elsewhere. 95 * Now that some interrupt handlers are threads, not setting it 96 * properly elsewhere can clobber it in the window between setting 97 * it here and returning to user mode, so don't waste time setting 98 * it perfectly here. 99 */ 100 if (td->td_priority != kg->kg_user_pri) { 101 mtx_lock_spin(&sched_lock); 102 td->td_priority = kg->kg_user_pri; 103 mtx_unlock_spin(&sched_lock); 104 } 105 106 /* 107 * We need to check to see if we have to exit or wait due to a 108 * single threading requirement or some other STOP condition. 109 * Don't bother doing all the work if the stop bits are not set 110 * at this time.. If we miss it, we miss it.. no big deal. 111 */ 112 if (P_SHOULDSTOP(p)) { 113 PROC_LOCK(p); 114 thread_suspend_check(0); /* Can suspend or kill */ 115 PROC_UNLOCK(p); 116 } 117 118 /* 119 * DO special thread processing, e.g. upcall tweaking and such 120 */ 121 if (p->p_flag & P_KSES) { 122 thread_userret(p, kg, ke, td, frame); 123 /* printf("KSE thread returned"); */ 124 } 125 126 /* 127 * Charge system time if profiling. 128 * 129 * XXX should move PS_PROFIL to a place that can obviously be 130 * accessed safely without sched_lock. 131 */ 132 if (p->p_sflag & PS_PROFIL) { 133 quad_t ticks; 134 135 mtx_lock_spin(&sched_lock); 136 ticks = ke->ke_sticks - oticks; 137 mtx_unlock_spin(&sched_lock); 138 addupc_task(ke, TRAPF_PC(frame), (u_int)ticks * psratio); 139 } 140} 141 142/* 143 * Process an asynchronous software trap. 144 * This is relatively easy. 145 * This function will return with preemption disabled. 146 */ 147void 148ast(struct trapframe *framep) 149{ 150 struct thread *td = curthread; 151 struct proc *p = td->td_proc; 152 struct kse *ke = td->td_kse; 153 struct ksegrp *kg = td->td_ksegrp; 154 u_int prticks, sticks; 155 int sflag; 156 int flags; 157 int sig; 158#if defined(DEV_NPX) && !defined(SMP) 159 int ucode; 160#endif 161 162 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 163 p->p_comm); 164 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 165#ifdef WITNESS 166 if (witness_list(td)) 167 panic("Returning to user mode with mutex(s) held"); 168#endif 169 mtx_assert(&Giant, MA_NOTOWNED); 170 mtx_assert(&sched_lock, MA_NOTOWNED); 171 prticks = 0; /* XXX: Quiet warning. */ 172 td->td_frame = framep; 173 /* 174 * This updates the p_sflag's for the checks below in one 175 * "atomic" operation with turning off the astpending flag. 176 * If another AST is triggered while we are handling the 177 * AST's saved in sflag, the astpending flag will be set and 178 * ast() will be called again. 179 */ 180 mtx_lock_spin(&sched_lock); 181 sticks = ke->ke_sticks; 182 sflag = p->p_sflag; 183 flags = ke->ke_flags; 184 p->p_sflag &= ~(PS_ALRMPEND | PS_NEEDSIGCHK | PS_PROFPEND); 185 ke->ke_flags &= ~(KEF_ASTPENDING | KEF_NEEDRESCHED | KEF_OWEUPC); 186 cnt.v_soft++; 187 if (flags & KEF_OWEUPC && sflag & PS_PROFIL) { 188 prticks = p->p_stats->p_prof.pr_ticks; 189 p->p_stats->p_prof.pr_ticks = 0; 190 } 191 mtx_unlock_spin(&sched_lock); 192 /* 193 * XXXKSE While the fact that we owe a user profiling 194 * tick is stored per KSE in this code, the statistics 195 * themselves are still stored per process. 196 * This should probably change, by which I mean that 197 * possibly the location of both might change. 198 */ 199 200 if (td->td_ucred != p->p_ucred) 201 cred_update_thread(td); 202 if (flags & KEF_OWEUPC && sflag & PS_PROFIL) 203 addupc_task(ke, p->p_stats->p_prof.pr_addr, prticks); 204 if (sflag & PS_ALRMPEND) { 205 PROC_LOCK(p); 206 psignal(p, SIGVTALRM); 207 PROC_UNLOCK(p); 208 } 209#if defined(DEV_NPX) && !defined(SMP) 210 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 211 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags, 212 PCB_NPXTRAP); 213 ucode = npxtrap(); 214 if (ucode != -1) { 215 trapsignal(p, SIGFPE, ucode); 216 } 217 } 218#endif 219 if (sflag & PS_PROFPEND) { 220 PROC_LOCK(p); 221 psignal(p, SIGPROF); 222 PROC_UNLOCK(p); 223 } 224 if (flags & KEF_NEEDRESCHED) { 225 mtx_lock_spin(&sched_lock); 226 td->td_priority = kg->kg_user_pri; 227 p->p_stats->p_ru.ru_nivcsw++; 228 mi_switch(); 229 mtx_unlock_spin(&sched_lock); 230 } 231 if (sflag & PS_NEEDSIGCHK) { 232 PROC_LOCK(p); 233 while ((sig = cursig(td)) != 0) 234 postsig(sig); 235 PROC_UNLOCK(p); 236 } 237 238 userret(td, framep, sticks); 239 mtx_assert(&Giant, MA_NOTOWNED); 240} 241