subr_syscall.c revision 104719
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 104719 2002-10-09 17:17:24Z jhb $ 39 */ 40 41#include "opt_mac.h" 42#ifdef __i386__ 43#include "opt_npx.h" 44#endif 45 46#include <sys/param.h> 47#include <sys/bus.h> 48#include <sys/kernel.h> 49#include <sys/lock.h> 50#include <sys/mac.h> 51#include <sys/mutex.h> 52#include <sys/proc.h> 53#include <sys/kse.h> 54#include <sys/ktr.h> 55#include <sys/resourcevar.h> 56#include <sys/signalvar.h> 57#include <sys/systm.h> 58#include <sys/vmmeter.h> 59#include <machine/cpu.h> 60#include <machine/pcb.h> 61 62/* 63 * Define the code needed before returning to user mode, for 64 * trap and syscall. 65 * 66 * MPSAFE 67 */ 68void 69userret(td, frame, oticks) 70 struct thread *td; 71 struct trapframe *frame; 72 u_int oticks; 73{ 74 struct proc *p = td->td_proc; 75 struct kse *ke = td->td_kse; 76 struct ksegrp *kg = td->td_ksegrp; 77 78 CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid, 79 p->p_comm); 80#ifdef INVARIANTS 81 /* Check that we called signotify() enough. */ 82 mtx_lock(&Giant); 83 PROC_LOCK(p); 84 mtx_lock_spin(&sched_lock); 85 if (SIGPENDING(p) && ((p->p_sflag & PS_NEEDSIGCHK) == 0 || 86 (td->td_kse->ke_flags & KEF_ASTPENDING) == 0)) 87 printf("failed to set signal flags properly for ast()\n"); 88 mtx_unlock_spin(&sched_lock); 89 PROC_UNLOCK(p); 90 mtx_unlock(&Giant); 91#endif 92 93#ifdef MAC 94 mac_thread_userret(td); 95#endif 96 97 /* 98 * XXX we cheat slightly on the locking here to avoid locking in 99 * the usual case. Setting td_priority here is essentially an 100 * incomplete workaround for not setting it properly elsewhere. 101 * Now that some interrupt handlers are threads, not setting it 102 * properly elsewhere can clobber it in the window between setting 103 * it here and returning to user mode, so don't waste time setting 104 * it perfectly here. 105 */ 106 if (td->td_priority != kg->kg_user_pri) { 107 mtx_lock_spin(&sched_lock); 108 td->td_priority = kg->kg_user_pri; 109 mtx_unlock_spin(&sched_lock); 110 } 111 112 /* 113 * We need to check to see if we have to exit or wait due to a 114 * single threading requirement or some other STOP condition. 115 * Don't bother doing all the work if the stop bits are not set 116 * at this time.. If we miss it, we miss it.. no big deal. 117 */ 118 if (P_SHOULDSTOP(p)) { 119 PROC_LOCK(p); 120 thread_suspend_check(0); /* Can suspend or kill */ 121 PROC_UNLOCK(p); 122 } 123 124 /* 125 * Do special thread processing, e.g. upcall tweaking and such. 126 */ 127 if (p->p_flag & P_KSES) { 128 thread_userret(td, frame); 129 /* printf("KSE thread returned"); */ 130 } 131 132 /* 133 * Charge system time if profiling. 134 * 135 * XXX should move PS_PROFIL to a place that can obviously be 136 * accessed safely without sched_lock. 137 */ 138 if (p->p_sflag & PS_PROFIL) { 139 quad_t ticks; 140 141 mtx_lock_spin(&sched_lock); 142 ticks = ke->ke_sticks - oticks; 143 mtx_unlock_spin(&sched_lock); 144 addupc_task(ke, TRAPF_PC(frame), (u_int)ticks * psratio); 145 } 146} 147 148/* 149 * Process an asynchronous software trap. 150 * This is relatively easy. 151 * This function will return with preemption disabled. 152 */ 153void 154ast(struct trapframe *framep) 155{ 156 struct thread *td; 157 struct proc *p; 158 struct kse *ke; 159 struct ksegrp *kg; 160 struct rlimit *rlim; 161 u_int prticks, sticks; 162 int sflag; 163 int flags; 164 int sig; 165#if defined(DEV_NPX) && !defined(SMP) 166 int ucode; 167#endif 168 169 td = curthread; 170 p = td->td_proc; 171 kg = td->td_ksegrp; 172 173 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 174 p->p_comm); 175 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 176#ifdef WITNESS 177 if (witness_list(td)) 178 panic("Returning to user mode with mutex(s) held"); 179#endif 180 mtx_assert(&Giant, MA_NOTOWNED); 181 mtx_assert(&sched_lock, MA_NOTOWNED); 182 td->td_frame = framep; 183 184 /* 185 * This updates the p_sflag's for the checks below in one 186 * "atomic" operation with turning off the astpending flag. 187 * If another AST is triggered while we are handling the 188 * AST's saved in sflag, the astpending flag will be set and 189 * ast() will be called again. 190 */ 191 mtx_lock_spin(&sched_lock); 192 ke = td->td_kse; 193 sticks = ke->ke_sticks; 194 flags = ke->ke_flags; 195 sflag = p->p_sflag; 196 p->p_sflag &= ~(PS_ALRMPEND | PS_NEEDSIGCHK | PS_PROFPEND | PS_XCPU); 197 ke->ke_flags &= ~(KEF_ASTPENDING | KEF_NEEDRESCHED | KEF_OWEUPC); 198 cnt.v_soft++; 199 prticks = 0; 200 if (flags & KEF_OWEUPC && sflag & PS_PROFIL) { 201 prticks = p->p_stats->p_prof.pr_ticks; 202 p->p_stats->p_prof.pr_ticks = 0; 203 } 204 mtx_unlock_spin(&sched_lock); 205 /* 206 * XXXKSE While the fact that we owe a user profiling 207 * tick is stored per KSE in this code, the statistics 208 * themselves are still stored per process. 209 * This should probably change, by which I mean that 210 * possibly the location of both might change. 211 */ 212 213 if (td->td_ucred != p->p_ucred) 214 cred_update_thread(td); 215 if (flags & KEF_OWEUPC && sflag & PS_PROFIL) 216 addupc_task(ke, p->p_stats->p_prof.pr_addr, prticks); 217 if (sflag & PS_ALRMPEND) { 218 PROC_LOCK(p); 219 psignal(p, SIGVTALRM); 220 PROC_UNLOCK(p); 221 } 222#if defined(DEV_NPX) && !defined(SMP) 223 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 224 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags, 225 PCB_NPXTRAP); 226 ucode = npxtrap(); 227 if (ucode != -1) { 228 trapsignal(p, SIGFPE, ucode); 229 } 230 } 231#endif 232 if (sflag & PS_PROFPEND) { 233 PROC_LOCK(p); 234 psignal(p, SIGPROF); 235 PROC_UNLOCK(p); 236 } 237 if (sflag & PS_XCPU) { 238 PROC_LOCK(p); 239 rlim = &p->p_rlimit[RLIMIT_CPU]; 240 if (p->p_runtime.sec >= rlim->rlim_max) 241 killproc(p, "exceeded maximum CPU limit"); 242 else { 243 psignal(p, SIGXCPU); 244 mtx_lock_spin(&sched_lock); 245 if (p->p_cpulimit < rlim->rlim_max) 246 p->p_cpulimit += 5; 247 mtx_unlock_spin(&sched_lock); 248 } 249 PROC_UNLOCK(p); 250 } 251 if (flags & KEF_NEEDRESCHED) { 252 mtx_lock_spin(&sched_lock); 253 td->td_priority = kg->kg_user_pri; 254 p->p_stats->p_ru.ru_nivcsw++; 255 mi_switch(); 256 mtx_unlock_spin(&sched_lock); 257 } 258 if (sflag & PS_NEEDSIGCHK) { 259 PROC_LOCK(p); 260 while ((sig = cursig(td)) != 0) 261 postsig(sig); 262 PROC_UNLOCK(p); 263 } 264 265 userret(td, framep, sticks); 266#ifdef DIAGNOSTIC 267 cred_free_thread(td); 268#endif 269 mtx_assert(&Giant, MA_NOTOWNED); 270} 271