subr_syscall.c revision 151316
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 151316 2005-10-14 12:43:47Z davidxu $"); 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/ktr.h> 57#include <sys/resourcevar.h> 58#include <sys/sched.h> 59#include <sys/signalvar.h> 60#include <sys/systm.h> 61#include <sys/vmmeter.h> 62#ifdef KTRACE 63#include <sys/uio.h> 64#include <sys/ktrace.h> 65#endif 66 67#include <machine/cpu.h> 68#include <machine/pcb.h> 69 70/* 71 * Define the code needed before returning to user mode, for 72 * trap and syscall. 73 * 74 * MPSAFE 75 */ 76void 77userret(td, frame, oticks) 78 struct thread *td; 79 struct trapframe *frame; 80 u_int oticks; 81{ 82 struct proc *p = td->td_proc; 83 84 CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid, 85 p->p_comm); 86#ifdef DIAGNOSTIC 87 /* Check that we called signotify() enough. */ 88 PROC_LOCK(p); 89 mtx_lock_spin(&sched_lock); 90 if (SIGPENDING(td) && ((td->td_flags & TDF_NEEDSIGCHK) == 0 || 91 (td->td_flags & TDF_ASTPENDING) == 0)) 92 printf("failed to set signal flags properly for ast()\n"); 93 mtx_unlock_spin(&sched_lock); 94 PROC_UNLOCK(p); 95#endif 96 97 /* 98 * If this thread tickled GEOM, we need to wait for the giggling to 99 * stop before we return to userland 100 */ 101 if (td->td_pflags & TDP_GEOM) 102 g_waitidle(); 103 104 /* 105 * We need to check to see if we have to exit or wait due to a 106 * single threading requirement or some other STOP condition. 107 * Don't bother doing all the work if the stop bits are not set 108 * at this time.. If we miss it, we miss it.. no big deal. 109 */ 110 if (P_SHOULDSTOP(p)) { 111 PROC_LOCK(p); 112 thread_suspend_check(0); /* Can suspend or kill */ 113 PROC_UNLOCK(p); 114 } 115 116 /* 117 * Do special thread processing, e.g. upcall tweaking and such. 118 */ 119 if (p->p_flag & P_SA) 120 thread_userret(td, frame); 121 122 /* 123 * Charge system time if profiling. 124 */ 125 if (p->p_flag & P_PROFIL) { 126 quad_t ticks; 127 128 ticks = td->td_sticks - oticks; 129 addupc_task(td, TRAPF_PC(frame), (u_int)ticks * psratio); 130 } 131 132 /* 133 * Let the scheduler adjust our priority etc. 134 */ 135 sched_userret(td); 136 KASSERT(td->td_locks == 0, 137 ("userret: Returning with %d locks held.", td->td_locks)); 138} 139 140/* 141 * Process an asynchronous software trap. 142 * This is relatively easy. 143 * This function will return with preemption disabled. 144 */ 145void 146ast(struct trapframe *framep) 147{ 148 struct thread *td; 149 struct proc *p; 150 struct ksegrp *kg; 151 struct rlimit rlim; 152 u_int sticks; 153 int sflag; 154 int flags; 155 int sig; 156#if defined(DEV_NPX) && !defined(SMP) 157 int ucode; 158 ksiginfo_t ksi; 159#endif 160 161 td = curthread; 162 p = td->td_proc; 163 kg = td->td_ksegrp; 164 165 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 166 p->p_comm); 167 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 168 WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode"); 169 mtx_assert(&Giant, MA_NOTOWNED); 170 mtx_assert(&sched_lock, MA_NOTOWNED); 171 td->td_frame = framep; 172 sticks = td->td_sticks; 173 174 if ((p->p_flag & P_SA) && (td->td_mailbox == NULL)) 175 thread_user_enter(td); 176 177 /* 178 * This updates the p_sflag's for the checks below in one 179 * "atomic" operation with turning off the astpending flag. 180 * If another AST is triggered while we are handling the 181 * AST's saved in sflag, the astpending flag will be set and 182 * ast() will be called again. 183 */ 184 mtx_lock_spin(&sched_lock); 185 flags = td->td_flags; 186 sflag = p->p_sflag; 187 p->p_sflag &= ~(PS_ALRMPEND | PS_PROFPEND | PS_XCPU); 188#ifdef MAC 189 p->p_sflag &= ~PS_MACPEND; 190#endif 191 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | 192 TDF_NEEDRESCHED | TDF_INTERRUPT); 193 cnt.v_soft++; 194 mtx_unlock_spin(&sched_lock); 195 196 /* 197 * XXXKSE While the fact that we owe a user profiling 198 * tick is stored per KSE in this code, the statistics 199 * themselves are still stored per process. 200 * This should probably change, by which I mean that 201 * possibly the location of both might change. 202 */ 203 if (td->td_ucred != p->p_ucred) 204 cred_update_thread(td); 205 if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) { 206 addupc_task(td, td->td_profil_addr, td->td_profil_ticks); 207 td->td_profil_ticks = 0; 208 td->td_pflags &= ~TDP_OWEUPC; 209 } 210 if (sflag & PS_ALRMPEND) { 211 PROC_LOCK(p); 212 psignal(p, SIGVTALRM); 213 PROC_UNLOCK(p); 214 } 215#if defined(DEV_NPX) && !defined(SMP) 216 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 217 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags, 218 PCB_NPXTRAP); 219 ucode = npxtrap(); 220 if (ucode != -1) { 221 ksiginfo_init_trap(&ksi); 222 ksi.ksi_signo = SIGFPE; 223 ksi.ksi_code = ucode; 224 trapsignal(td, &ksi); 225 } 226 } 227#endif 228 if (sflag & PS_PROFPEND) { 229 PROC_LOCK(p); 230 psignal(p, SIGPROF); 231 PROC_UNLOCK(p); 232 } 233 if (sflag & PS_XCPU) { 234 PROC_LOCK(p); 235 lim_rlimit(p, RLIMIT_CPU, &rlim); 236 mtx_lock_spin(&sched_lock); 237 if (p->p_rux.rux_runtime.sec >= rlim.rlim_max) { 238 mtx_unlock_spin(&sched_lock); 239 killproc(p, "exceeded maximum CPU limit"); 240 } else { 241 if (p->p_cpulimit < rlim.rlim_max) 242 p->p_cpulimit += 5; 243 mtx_unlock_spin(&sched_lock); 244 psignal(p, SIGXCPU); 245 } 246 PROC_UNLOCK(p); 247 } 248#ifdef MAC 249 if (sflag & PS_MACPEND) 250 mac_thread_userret(td); 251#endif 252 if (flags & TDF_NEEDRESCHED) { 253#ifdef KTRACE 254 if (KTRPOINT(td, KTR_CSW)) 255 ktrcsw(1, 1); 256#endif 257 mtx_lock_spin(&sched_lock); 258 sched_prio(td, kg->kg_user_pri); 259 mi_switch(SW_INVOL, NULL); 260 mtx_unlock_spin(&sched_lock); 261#ifdef KTRACE 262 if (KTRPOINT(td, KTR_CSW)) 263 ktrcsw(0, 1); 264#endif 265 } 266 if (flags & TDF_NEEDSIGCHK) { 267 PROC_LOCK(p); 268 mtx_lock(&p->p_sigacts->ps_mtx); 269 while ((sig = cursig(td)) != 0) 270 postsig(sig); 271 mtx_unlock(&p->p_sigacts->ps_mtx); 272 PROC_UNLOCK(p); 273 } 274 275 userret(td, framep, sticks); 276 mtx_assert(&Giant, MA_NOTOWNED); 277} 278