subr_syscall.c revision 106655
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 106655 2002-11-08 19:00:17Z rwatson $ 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/sched.h> 57#include <sys/signalvar.h> 58#include <sys/systm.h> 59#include <sys/vmmeter.h> 60#include <machine/cpu.h> 61#include <machine/pcb.h> 62 63/* 64 * Define the code needed before returning to user mode, for 65 * trap and syscall. 66 * 67 * MPSAFE 68 */ 69void 70userret(td, frame, oticks) 71 struct thread *td; 72 struct trapframe *frame; 73 u_int oticks; 74{ 75 struct proc *p = td->td_proc; 76 struct kse *ke = td->td_kse; 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 /* 94 * Let the scheduler adjust our priority etc. 95 */ 96 sched_userret(td); 97 98 /* 99 * We need to check to see if we have to exit or wait due to a 100 * single threading requirement or some other STOP condition. 101 * Don't bother doing all the work if the stop bits are not set 102 * at this time.. If we miss it, we miss it.. no big deal. 103 */ 104 if (P_SHOULDSTOP(p)) { 105 PROC_LOCK(p); 106 thread_suspend_check(0); /* Can suspend or kill */ 107 PROC_UNLOCK(p); 108 } 109 110 /* 111 * Do special thread processing, e.g. upcall tweaking and such. 112 */ 113 if (p->p_flag & P_KSES) { 114 thread_userret(td, frame); 115 /* printf("KSE thread returned"); */ 116 } 117 118 /* 119 * Charge system time if profiling. 120 * 121 * XXX should move PS_PROFIL to a place that can obviously be 122 * accessed safely without sched_lock. 123 */ 124 if (p->p_sflag & PS_PROFIL) { 125 quad_t ticks; 126 127 mtx_lock_spin(&sched_lock); 128 ticks = ke->ke_sticks - oticks; 129 mtx_unlock_spin(&sched_lock); 130 addupc_task(ke, TRAPF_PC(frame), (u_int)ticks * psratio); 131 } 132} 133 134/* 135 * Process an asynchronous software trap. 136 * This is relatively easy. 137 * This function will return with preemption disabled. 138 */ 139void 140ast(struct trapframe *framep) 141{ 142 struct thread *td; 143 struct proc *p; 144 struct kse *ke; 145 struct ksegrp *kg; 146 struct rlimit *rlim; 147 u_int prticks, sticks; 148 int sflag; 149 int flags; 150 int sig; 151#if defined(DEV_NPX) && !defined(SMP) 152 int ucode; 153#endif 154 155 td = curthread; 156 p = td->td_proc; 157 kg = td->td_ksegrp; 158 159 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 160 p->p_comm); 161 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 162#ifdef WITNESS 163 if (witness_list(td)) 164 panic("Returning to user mode with mutex(s) held"); 165#endif 166 mtx_assert(&Giant, MA_NOTOWNED); 167 mtx_assert(&sched_lock, MA_NOTOWNED); 168 td->td_frame = framep; 169 170 /* 171 * This updates the p_sflag's for the checks below in one 172 * "atomic" operation with turning off the astpending flag. 173 * If another AST is triggered while we are handling the 174 * AST's saved in sflag, the astpending flag will be set and 175 * ast() will be called again. 176 */ 177 mtx_lock_spin(&sched_lock); 178 ke = td->td_kse; 179 sticks = ke->ke_sticks; 180 flags = ke->ke_flags; 181 sflag = p->p_sflag; 182 p->p_sflag &= ~(PS_ALRMPEND | PS_NEEDSIGCHK | PS_PROFPEND | PS_XCPU); 183#ifdef MAC 184 p->p_sflag &= ~PS_MACPEND; 185#endif 186 ke->ke_flags &= ~(KEF_ASTPENDING | KEF_NEEDRESCHED | KEF_OWEUPC); 187 cnt.v_soft++; 188 prticks = 0; 189 if (flags & KEF_OWEUPC && sflag & PS_PROFIL) { 190 prticks = p->p_stats->p_prof.pr_ticks; 191 p->p_stats->p_prof.pr_ticks = 0; 192 } 193 mtx_unlock_spin(&sched_lock); 194 /* 195 * XXXKSE While the fact that we owe a user profiling 196 * tick is stored per KSE in this code, the statistics 197 * themselves are still stored per process. 198 * This should probably change, by which I mean that 199 * possibly the location of both might change. 200 */ 201 202 if (td->td_ucred != p->p_ucred) 203 cred_update_thread(td); 204 if (flags & KEF_OWEUPC && sflag & PS_PROFIL) 205 addupc_task(ke, p->p_stats->p_prof.pr_addr, prticks); 206 if (sflag & PS_ALRMPEND) { 207 PROC_LOCK(p); 208 psignal(p, SIGVTALRM); 209 PROC_UNLOCK(p); 210 } 211#if defined(DEV_NPX) && !defined(SMP) 212 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 213 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags, 214 PCB_NPXTRAP); 215 ucode = npxtrap(); 216 if (ucode != -1) { 217 trapsignal(p, SIGFPE, ucode); 218 } 219 } 220#endif 221 if (sflag & PS_PROFPEND) { 222 PROC_LOCK(p); 223 psignal(p, SIGPROF); 224 PROC_UNLOCK(p); 225 } 226 if (sflag & PS_XCPU) { 227 PROC_LOCK(p); 228 rlim = &p->p_rlimit[RLIMIT_CPU]; 229 if (p->p_runtime.sec >= rlim->rlim_max) 230 killproc(p, "exceeded maximum CPU limit"); 231 else { 232 psignal(p, SIGXCPU); 233 mtx_lock_spin(&sched_lock); 234 if (p->p_cpulimit < rlim->rlim_max) 235 p->p_cpulimit += 5; 236 mtx_unlock_spin(&sched_lock); 237 } 238 PROC_UNLOCK(p); 239 } 240#ifdef MAC 241 if (sflag & PS_MACPEND) 242 mac_thread_userret(td); 243#endif 244 if (flags & KEF_NEEDRESCHED) { 245 mtx_lock_spin(&sched_lock); 246 sched_prio(td, kg->kg_user_pri); 247 p->p_stats->p_ru.ru_nivcsw++; 248 mi_switch(); 249 mtx_unlock_spin(&sched_lock); 250 } 251 if (sflag & PS_NEEDSIGCHK) { 252 PROC_LOCK(p); 253 while ((sig = cursig(td)) != 0) 254 postsig(sig); 255 PROC_UNLOCK(p); 256 } 257 258 userret(td, framep, sticks); 259#ifdef DIAGNOSTIC 260 cred_free_thread(td); 261#endif 262 mtx_assert(&Giant, MA_NOTOWNED); 263} 264