subr_syscall.c revision 139452
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 139452 2004-12-30 20:30:58Z jhb $"); 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} 137 138/* 139 * Process an asynchronous software trap. 140 * This is relatively easy. 141 * This function will return with preemption disabled. 142 */ 143void 144ast(struct trapframe *framep) 145{ 146 struct thread *td; 147 struct proc *p; 148 struct ksegrp *kg; 149 struct rlimit rlim; 150 u_int sticks; 151 int sflag; 152 int flags; 153 int sig; 154#if defined(DEV_NPX) && !defined(SMP) 155 int ucode; 156#endif 157 158 td = curthread; 159 p = td->td_proc; 160 kg = td->td_ksegrp; 161 162 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 163 p->p_comm); 164 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 165 WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode"); 166 mtx_assert(&Giant, MA_NOTOWNED); 167 mtx_assert(&sched_lock, MA_NOTOWNED); 168 td->td_frame = framep; 169 sticks = td->td_sticks; 170 171 if ((p->p_flag & P_SA) && (td->td_mailbox == NULL)) 172 thread_user_enter(td); 173 174 /* 175 * This updates the p_sflag's for the checks below in one 176 * "atomic" operation with turning off the astpending flag. 177 * If another AST is triggered while we are handling the 178 * AST's saved in sflag, the astpending flag will be set and 179 * ast() will be called again. 180 */ 181 mtx_lock_spin(&sched_lock); 182 flags = td->td_flags; 183 sflag = p->p_sflag; 184 p->p_sflag &= ~(PS_ALRMPEND | PS_PROFPEND | PS_XCPU); 185#ifdef MAC 186 p->p_sflag &= ~PS_MACPEND; 187#endif 188 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | 189 TDF_NEEDRESCHED | TDF_INTERRUPT); 190 cnt.v_soft++; 191 mtx_unlock_spin(&sched_lock); 192 193 /* 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 if (td->td_ucred != p->p_ucred) 201 cred_update_thread(td); 202 if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) { 203 addupc_task(td, td->td_profil_addr, td->td_profil_ticks); 204 td->td_profil_ticks = 0; 205 td->td_pflags &= ~TDP_OWEUPC; 206 } 207 if (sflag & PS_ALRMPEND) { 208 PROC_LOCK(p); 209 psignal(p, SIGVTALRM); 210 PROC_UNLOCK(p); 211 } 212#if defined(DEV_NPX) && !defined(SMP) 213 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 214 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags, 215 PCB_NPXTRAP); 216 ucode = npxtrap(); 217 if (ucode != -1) { 218 trapsignal(td, SIGFPE, ucode); 219 } 220 } 221#endif 222 if (sflag & PS_PROFPEND) { 223 PROC_LOCK(p); 224 psignal(p, SIGPROF); 225 PROC_UNLOCK(p); 226 } 227 if (sflag & PS_XCPU) { 228 PROC_LOCK(p); 229 lim_rlimit(p, RLIMIT_CPU, &rlim); 230 mtx_lock_spin(&sched_lock); 231 if (p->p_rux.rux_runtime.sec >= rlim.rlim_max) { 232 mtx_unlock_spin(&sched_lock); 233 killproc(p, "exceeded maximum CPU limit"); 234 } else { 235 if (p->p_cpulimit < rlim.rlim_max) 236 p->p_cpulimit += 5; 237 mtx_unlock_spin(&sched_lock); 238 psignal(p, SIGXCPU); 239 } 240 PROC_UNLOCK(p); 241 } 242#ifdef MAC 243 if (sflag & PS_MACPEND) 244 mac_thread_userret(td); 245#endif 246 if (flags & TDF_NEEDRESCHED) { 247#ifdef KTRACE 248 if (KTRPOINT(td, KTR_CSW)) 249 ktrcsw(1, 1); 250#endif 251 mtx_lock_spin(&sched_lock); 252 sched_prio(td, kg->kg_user_pri); 253 mi_switch(SW_INVOL, NULL); 254 mtx_unlock_spin(&sched_lock); 255#ifdef KTRACE 256 if (KTRPOINT(td, KTR_CSW)) 257 ktrcsw(0, 1); 258#endif 259 } 260 if (flags & TDF_NEEDSIGCHK) { 261 PROC_LOCK(p); 262 mtx_lock(&p->p_sigacts->ps_mtx); 263 while ((sig = cursig(td)) != 0) 264 postsig(sig); 265 mtx_unlock(&p->p_sigacts->ps_mtx); 266 PROC_UNLOCK(p); 267 } 268 269 userret(td, framep, sticks); 270 mtx_assert(&Giant, MA_NOTOWNED); 271} 272