subr_syscall.c revision 144101
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 144101 2005-03-25 09:56:56Z jeff $"); 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#if 0 137 /* This is not presently working. */ 138 KASSERT(td->td_locks == 0, 139 ("userret: Returning with %d locks held.", td->td_locks)); 140#endif 141} 142 143/* 144 * Process an asynchronous software trap. 145 * This is relatively easy. 146 * This function will return with preemption disabled. 147 */ 148void 149ast(struct trapframe *framep) 150{ 151 struct thread *td; 152 struct proc *p; 153 struct ksegrp *kg; 154 struct rlimit rlim; 155 u_int sticks; 156 int sflag; 157 int flags; 158 int sig; 159#if defined(DEV_NPX) && !defined(SMP) 160 int ucode; 161#endif 162 163 td = curthread; 164 p = td->td_proc; 165 kg = td->td_ksegrp; 166 167 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 168 p->p_comm); 169 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 170 WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode"); 171 mtx_assert(&Giant, MA_NOTOWNED); 172 mtx_assert(&sched_lock, MA_NOTOWNED); 173 td->td_frame = framep; 174 sticks = td->td_sticks; 175 176 if ((p->p_flag & P_SA) && (td->td_mailbox == NULL)) 177 thread_user_enter(td); 178 179 /* 180 * This updates the p_sflag's for the checks below in one 181 * "atomic" operation with turning off the astpending flag. 182 * If another AST is triggered while we are handling the 183 * AST's saved in sflag, the astpending flag will be set and 184 * ast() will be called again. 185 */ 186 mtx_lock_spin(&sched_lock); 187 flags = td->td_flags; 188 sflag = p->p_sflag; 189 p->p_sflag &= ~(PS_ALRMPEND | PS_PROFPEND | PS_XCPU); 190#ifdef MAC 191 p->p_sflag &= ~PS_MACPEND; 192#endif 193 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | 194 TDF_NEEDRESCHED | TDF_INTERRUPT); 195 cnt.v_soft++; 196 mtx_unlock_spin(&sched_lock); 197 198 /* 199 * XXXKSE While the fact that we owe a user profiling 200 * tick is stored per KSE in this code, the statistics 201 * themselves are still stored per process. 202 * This should probably change, by which I mean that 203 * possibly the location of both might change. 204 */ 205 if (td->td_ucred != p->p_ucred) 206 cred_update_thread(td); 207 if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) { 208 addupc_task(td, td->td_profil_addr, td->td_profil_ticks); 209 td->td_profil_ticks = 0; 210 td->td_pflags &= ~TDP_OWEUPC; 211 } 212 if (sflag & PS_ALRMPEND) { 213 PROC_LOCK(p); 214 psignal(p, SIGVTALRM); 215 PROC_UNLOCK(p); 216 } 217#if defined(DEV_NPX) && !defined(SMP) 218 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 219 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags, 220 PCB_NPXTRAP); 221 ucode = npxtrap(); 222 if (ucode != -1) { 223 trapsignal(td, SIGFPE, ucode); 224 } 225 } 226#endif 227 if (sflag & PS_PROFPEND) { 228 PROC_LOCK(p); 229 psignal(p, SIGPROF); 230 PROC_UNLOCK(p); 231 } 232 if (sflag & PS_XCPU) { 233 PROC_LOCK(p); 234 lim_rlimit(p, RLIMIT_CPU, &rlim); 235 mtx_lock_spin(&sched_lock); 236 if (p->p_rux.rux_runtime.sec >= rlim.rlim_max) { 237 mtx_unlock_spin(&sched_lock); 238 killproc(p, "exceeded maximum CPU limit"); 239 } else { 240 if (p->p_cpulimit < rlim.rlim_max) 241 p->p_cpulimit += 5; 242 mtx_unlock_spin(&sched_lock); 243 psignal(p, SIGXCPU); 244 } 245 PROC_UNLOCK(p); 246 } 247#ifdef MAC 248 if (sflag & PS_MACPEND) 249 mac_thread_userret(td); 250#endif 251 if (flags & TDF_NEEDRESCHED) { 252#ifdef KTRACE 253 if (KTRPOINT(td, KTR_CSW)) 254 ktrcsw(1, 1); 255#endif 256 mtx_lock_spin(&sched_lock); 257 sched_prio(td, kg->kg_user_pri); 258 mi_switch(SW_INVOL, NULL); 259 mtx_unlock_spin(&sched_lock); 260#ifdef KTRACE 261 if (KTRPOINT(td, KTR_CSW)) 262 ktrcsw(0, 1); 263#endif 264 } 265 if (flags & TDF_NEEDSIGCHK) { 266 PROC_LOCK(p); 267 mtx_lock(&p->p_sigacts->ps_mtx); 268 while ((sig = cursig(td)) != 0) 269 postsig(sig); 270 mtx_unlock(&p->p_sigacts->ps_mtx); 271 PROC_UNLOCK(p); 272 } 273 274 userret(td, framep, sticks); 275 mtx_assert(&Giant, MA_NOTOWNED); 276} 277