subr_syscall.c revision 118240
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 */ 39 40#include <sys/cdefs.h> 41__FBSDID("$FreeBSD: head/sys/kern/subr_trap.c 118240 2003-07-31 01:36:24Z peter $"); 42 43#include "opt_ktrace.h" 44#include "opt_mac.h" 45#ifdef __i386__ 46#include "opt_npx.h" 47#endif 48 49#include <sys/param.h> 50#include <sys/bus.h> 51#include <sys/kernel.h> 52#include <sys/lock.h> 53#include <sys/mac.h> 54#include <sys/mutex.h> 55#include <sys/proc.h> 56#include <sys/kse.h> 57#include <sys/ktr.h> 58#include <sys/resourcevar.h> 59#include <sys/sched.h> 60#include <sys/signalvar.h> 61#include <sys/systm.h> 62#include <sys/vmmeter.h> 63#ifdef KTRACE 64#include <sys/uio.h> 65#include <sys/ktrace.h> 66#endif 67 68#include <machine/cpu.h> 69#include <machine/pcb.h> 70 71/* 72 * Define the code needed before returning to user mode, for 73 * trap and syscall. 74 * 75 * MPSAFE 76 */ 77void 78userret(td, frame, oticks) 79 struct thread *td; 80 struct trapframe *frame; 81 u_int oticks; 82{ 83 struct proc *p = td->td_proc; 84 85 CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid, 86 p->p_comm); 87#ifdef INVARIANTS 88 /* Check that we called signotify() enough. */ 89 PROC_LOCK(p); 90 mtx_lock_spin(&sched_lock); 91 if (SIGPENDING(td) && ((td->td_flags & TDF_NEEDSIGCHK) == 0 || 92 (td->td_flags & TDF_ASTPENDING) == 0)) 93 printf("failed to set signal flags properly for ast()\n"); 94 mtx_unlock_spin(&sched_lock); 95 PROC_UNLOCK(p); 96#endif 97 98 /* 99 * Let the scheduler adjust our priority etc. 100 */ 101 sched_userret(td); 102 103 /* 104 * We need to check to see if we have to exit or wait due to a 105 * single threading requirement or some other STOP condition. 106 * Don't bother doing all the work if the stop bits are not set 107 * at this time.. If we miss it, we miss it.. no big deal. 108 */ 109 if (P_SHOULDSTOP(p)) { 110 PROC_LOCK(p); 111 thread_suspend_check(0); /* Can suspend or kill */ 112 PROC_UNLOCK(p); 113 } 114 115 /* 116 * Do special thread processing, e.g. upcall tweaking and such. 117 */ 118 if (p->p_flag & P_SA) { 119 thread_userret(td, frame); 120 } 121 122 /* 123 * Charge system time if profiling. 124 */ 125 if (p->p_flag & P_PROFIL) { 126 quad_t ticks; 127 128 mtx_lock_spin(&sched_lock); 129 ticks = td->td_sticks - oticks; 130 mtx_unlock_spin(&sched_lock); 131 addupc_task(td, TRAPF_PC(frame), (u_int)ticks * psratio); 132 } 133} 134 135/* 136 * Process an asynchronous software trap. 137 * This is relatively easy. 138 * This function will return with preemption disabled. 139 */ 140void 141ast(struct trapframe *framep) 142{ 143 struct thread *td; 144 struct proc *p; 145 struct kse *ke; 146 struct ksegrp *kg; 147 struct rlimit *rlim; 148 u_int prticks, sticks; 149 int sflag; 150 int flags; 151 int sig; 152#if defined(DEV_NPX) && !defined(SMP) 153 int ucode; 154#endif 155 156 td = curthread; 157 p = td->td_proc; 158 kg = td->td_ksegrp; 159 160 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 161 p->p_comm); 162 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 163 WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode"); 164 mtx_assert(&Giant, MA_NOTOWNED); 165 mtx_assert(&sched_lock, MA_NOTOWNED); 166 td->td_frame = framep; 167 168 /* 169 * This updates the p_sflag's for the checks below in one 170 * "atomic" operation with turning off the astpending flag. 171 * If another AST is triggered while we are handling the 172 * AST's saved in sflag, the astpending flag will be set and 173 * ast() will be called again. 174 */ 175 mtx_lock_spin(&sched_lock); 176 ke = td->td_kse; 177 sticks = td->td_sticks; 178 flags = td->td_flags; 179 sflag = p->p_sflag; 180 p->p_sflag &= ~(PS_ALRMPEND | PS_PROFPEND | PS_XCPU); 181#ifdef MAC 182 p->p_sflag &= ~PS_MACPEND; 183#endif 184 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | 185 TDF_NEEDRESCHED | TDF_OWEUPC | TDF_INTERRUPT); 186 cnt.v_soft++; 187 prticks = 0; 188 if (flags & TDF_OWEUPC && p->p_flag & P_PROFIL) { 189 prticks = p->p_stats->p_prof.pr_ticks; 190 p->p_stats->p_prof.pr_ticks = 0; 191 } 192 mtx_unlock_spin(&sched_lock); 193 /* 194 * XXXKSE While the fact that we owe a user profiling 195 * tick is stored per KSE in this code, the statistics 196 * themselves are still stored per process. 197 * This should probably change, by which I mean that 198 * possibly the location of both might change. 199 */ 200 201 if (td->td_ucred != p->p_ucred) 202 cred_update_thread(td); 203 if (flags & TDF_OWEUPC && p->p_flag & P_PROFIL) 204 addupc_task(td, p->p_stats->p_prof.pr_addr, prticks); 205 if (sflag & PS_ALRMPEND) { 206 PROC_LOCK(p); 207 psignal(p, SIGVTALRM); 208 PROC_UNLOCK(p); 209 } 210#if defined(DEV_NPX) && !defined(SMP) 211 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 212 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags, 213 PCB_NPXTRAP); 214 ucode = npxtrap(); 215 if (ucode != -1) { 216 trapsignal(td, SIGFPE, ucode); 217 } 218 } 219#endif 220 if (sflag & PS_PROFPEND) { 221 PROC_LOCK(p); 222 psignal(p, SIGPROF); 223 PROC_UNLOCK(p); 224 } 225 if (sflag & PS_XCPU) { 226 PROC_LOCK(p); 227 rlim = &p->p_rlimit[RLIMIT_CPU]; 228 mtx_lock_spin(&sched_lock); 229 if (p->p_runtime.sec >= rlim->rlim_max) { 230 mtx_unlock_spin(&sched_lock); 231 killproc(p, "exceeded maximum CPU limit"); 232 } else { 233 if (p->p_cpulimit < rlim->rlim_max) 234 p->p_cpulimit += 5; 235 mtx_unlock_spin(&sched_lock); 236 psignal(p, SIGXCPU); 237 } 238 PROC_UNLOCK(p); 239 } 240#ifdef MAC 241 if (sflag & PS_MACPEND) 242 mac_thread_userret(td); 243#endif 244 if (flags & TDF_NEEDRESCHED) { 245#ifdef KTRACE 246 if (KTRPOINT(td, KTR_CSW)) 247 ktrcsw(1, 0); 248#endif 249 mtx_lock_spin(&sched_lock); 250 sched_prio(td, kg->kg_user_pri); 251 p->p_stats->p_ru.ru_nivcsw++; 252 mi_switch(); 253 mtx_unlock_spin(&sched_lock); 254#ifdef KTRACE 255 if (KTRPOINT(td, KTR_CSW)) 256 ktrcsw(0, 0); 257#endif 258 } 259 if (flags & TDF_NEEDSIGCHK) { 260 PROC_LOCK(p); 261 mtx_lock(&p->p_sigacts->ps_mtx); 262 while ((sig = cursig(td)) != 0) 263 postsig(sig); 264 mtx_unlock(&p->p_sigacts->ps_mtx); 265 PROC_UNLOCK(p); 266 } 267 268 userret(td, framep, sticks); 269#ifdef DIAGNOSTIC 270 cred_free_thread(td); 271#endif 272 mtx_assert(&Giant, MA_NOTOWNED); 273} 274