subr_syscall.c revision 114983
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 114983 2003-05-13 20:36:02Z 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/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 77 CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid, 78 p->p_comm); 79#ifdef INVARIANTS 80 /* Check that we called signotify() enough. */ 81 PROC_LOCK(p); 82 mtx_lock_spin(&sched_lock); 83 if (SIGPENDING(td) && ((td->td_flags & TDF_NEEDSIGCHK) == 0 || 84 (td->td_flags & TDF_ASTPENDING) == 0)) 85 printf("failed to set signal flags properly for ast()\n"); 86 mtx_unlock_spin(&sched_lock); 87 PROC_UNLOCK(p); 88#endif 89 90 /* 91 * Let the scheduler adjust our priority etc. 92 */ 93 sched_userret(td); 94 95 /* 96 * We need to check to see if we have to exit or wait due to a 97 * single threading requirement or some other STOP condition. 98 * Don't bother doing all the work if the stop bits are not set 99 * at this time.. If we miss it, we miss it.. no big deal. 100 */ 101 if (P_SHOULDSTOP(p)) { 102 PROC_LOCK(p); 103 thread_suspend_check(0); /* Can suspend or kill */ 104 PROC_UNLOCK(p); 105 } 106 107 /* 108 * Do special thread processing, e.g. upcall tweaking and such. 109 */ 110 if (p->p_flag & P_THREADED) { 111 thread_userret(td, frame); 112 } 113 114 /* 115 * Charge system time if profiling. 116 */ 117 if (p->p_flag & P_PROFIL) { 118 quad_t ticks; 119 120 mtx_lock_spin(&sched_lock); 121 ticks = td->td_sticks - oticks; 122 mtx_unlock_spin(&sched_lock); 123 addupc_task(td, TRAPF_PC(frame), (u_int)ticks * psratio); 124 } 125} 126 127/* 128 * Process an asynchronous software trap. 129 * This is relatively easy. 130 * This function will return with preemption disabled. 131 */ 132void 133ast(struct trapframe *framep) 134{ 135 struct thread *td; 136 struct proc *p; 137 struct kse *ke; 138 struct ksegrp *kg; 139 struct rlimit *rlim; 140 u_int prticks, sticks; 141 int sflag; 142 int flags; 143 int sig; 144#if defined(DEV_NPX) && !defined(SMP) 145 int ucode; 146#endif 147 148 td = curthread; 149 p = td->td_proc; 150 kg = td->td_ksegrp; 151 152 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 153 p->p_comm); 154 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 155 WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode"); 156 mtx_assert(&Giant, MA_NOTOWNED); 157 mtx_assert(&sched_lock, MA_NOTOWNED); 158 td->td_frame = framep; 159 160 /* 161 * This updates the p_sflag's for the checks below in one 162 * "atomic" operation with turning off the astpending flag. 163 * If another AST is triggered while we are handling the 164 * AST's saved in sflag, the astpending flag will be set and 165 * ast() will be called again. 166 */ 167 mtx_lock_spin(&sched_lock); 168 ke = td->td_kse; 169 sticks = td->td_sticks; 170 flags = td->td_flags; 171 sflag = p->p_sflag; 172 p->p_sflag &= ~(PS_ALRMPEND | PS_PROFPEND | PS_XCPU); 173#ifdef MAC 174 p->p_sflag &= ~PS_MACPEND; 175#endif 176 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | 177 TDF_NEEDRESCHED | TDF_OWEUPC); 178 cnt.v_soft++; 179 prticks = 0; 180 if (flags & TDF_OWEUPC && p->p_flag & P_PROFIL) { 181 prticks = p->p_stats->p_prof.pr_ticks; 182 p->p_stats->p_prof.pr_ticks = 0; 183 } 184 mtx_unlock_spin(&sched_lock); 185 /* 186 * XXXKSE While the fact that we owe a user profiling 187 * tick is stored per KSE in this code, the statistics 188 * themselves are still stored per process. 189 * This should probably change, by which I mean that 190 * possibly the location of both might change. 191 */ 192 193 if (td->td_ucred != p->p_ucred) 194 cred_update_thread(td); 195 if (flags & TDF_OWEUPC && p->p_flag & P_PROFIL) 196 addupc_task(td, p->p_stats->p_prof.pr_addr, prticks); 197 if (sflag & PS_ALRMPEND) { 198 PROC_LOCK(p); 199 psignal(p, SIGVTALRM); 200 PROC_UNLOCK(p); 201 } 202#if defined(DEV_NPX) && !defined(SMP) 203 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 204 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags, 205 PCB_NPXTRAP); 206 ucode = npxtrap(); 207 if (ucode != -1) { 208 trapsignal(td, SIGFPE, ucode); 209 } 210 } 211#endif 212 if (sflag & PS_PROFPEND) { 213 PROC_LOCK(p); 214 psignal(p, SIGPROF); 215 PROC_UNLOCK(p); 216 } 217 if (sflag & PS_XCPU) { 218 PROC_LOCK(p); 219 rlim = &p->p_rlimit[RLIMIT_CPU]; 220 mtx_lock_spin(&sched_lock); 221 if (p->p_runtime.sec >= rlim->rlim_max) { 222 mtx_unlock_spin(&sched_lock); 223 killproc(p, "exceeded maximum CPU limit"); 224 } else { 225 if (p->p_cpulimit < rlim->rlim_max) 226 p->p_cpulimit += 5; 227 mtx_unlock_spin(&sched_lock); 228 psignal(p, SIGXCPU); 229 } 230 PROC_UNLOCK(p); 231 } 232#ifdef MAC 233 if (sflag & PS_MACPEND) 234 mac_thread_userret(td); 235#endif 236 if (flags & TDF_NEEDRESCHED) { 237 mtx_lock_spin(&sched_lock); 238 sched_prio(td, kg->kg_user_pri); 239 p->p_stats->p_ru.ru_nivcsw++; 240 mi_switch(); 241 mtx_unlock_spin(&sched_lock); 242 } 243 if (flags & TDF_NEEDSIGCHK) { 244 int sigs; 245 246 sigs = 0; 247 PROC_LOCK(p); 248 mtx_lock(&p->p_sigacts->ps_mtx); 249 while ((sig = cursig(td)) != 0) { 250 postsig(sig); 251 sigs++; 252 } 253 mtx_unlock(&p->p_sigacts->ps_mtx); 254 PROC_UNLOCK(p); 255 if (p->p_flag & P_THREADED && sigs) { 256 struct kse_upcall *ku = td->td_upcall; 257 if ((void *)TRAPF_PC(framep) != ku->ku_func) { 258 mtx_lock_spin(&sched_lock); 259 ku->ku_flags |= KUF_DOUPCALL; 260 mtx_unlock_spin(&sched_lock); 261 } 262 } 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