subr_syscall.c revision 111883
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 111883 2003-03-04 21:03:05Z 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 mtx_lock(&Giant); 82 PROC_LOCK(p); 83 mtx_lock_spin(&sched_lock); 84 if (SIGPENDING(p) && ((p->p_sflag & PS_NEEDSIGCHK) == 0 || 85 (td->td_flags & TDF_ASTPENDING) == 0)) 86 printf("failed to set signal flags properly for ast()\n"); 87 mtx_unlock_spin(&sched_lock); 88 PROC_UNLOCK(p); 89 mtx_unlock(&Giant); 90#endif 91 92 /* 93 * Let the scheduler adjust our priority etc. 94 */ 95 sched_userret(td); 96 97 /* 98 * We need to check to see if we have to exit or wait due to a 99 * single threading requirement or some other STOP condition. 100 * Don't bother doing all the work if the stop bits are not set 101 * at this time.. If we miss it, we miss it.. no big deal. 102 */ 103 if (P_SHOULDSTOP(p)) { 104 PROC_LOCK(p); 105 thread_suspend_check(0); /* Can suspend or kill */ 106 PROC_UNLOCK(p); 107 } 108 109 /* 110 * Do special thread processing, e.g. upcall tweaking and such. 111 */ 112 if (p->p_flag & P_THREADED) { 113 thread_userret(td, frame); 114 } 115 116 /* 117 * Charge system time if profiling. 118 * 119 * XXX should move PS_PROFIL to a place that can obviously be 120 * accessed safely without sched_lock. 121 */ 122 if (p->p_sflag & PS_PROFIL) { 123 quad_t ticks; 124 125 mtx_lock_spin(&sched_lock); 126 ticks = td->td_sticks - oticks; 127 mtx_unlock_spin(&sched_lock); 128 addupc_task(td, TRAPF_PC(frame), (u_int)ticks * psratio); 129 } 130} 131 132/* 133 * Process an asynchronous software trap. 134 * This is relatively easy. 135 * This function will return with preemption disabled. 136 */ 137void 138ast(struct trapframe *framep) 139{ 140 struct thread *td; 141 struct proc *p; 142 struct kse *ke; 143 struct ksegrp *kg; 144 struct rlimit *rlim; 145 u_int prticks, sticks; 146 int sflag; 147 int flags; 148 int sig; 149#if defined(DEV_NPX) && !defined(SMP) 150 int ucode; 151#endif 152 153 td = curthread; 154 p = td->td_proc; 155 kg = td->td_ksegrp; 156 157 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 158 p->p_comm); 159 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 160 WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode"); 161 mtx_assert(&Giant, MA_NOTOWNED); 162 mtx_assert(&sched_lock, MA_NOTOWNED); 163 td->td_frame = framep; 164 165 /* 166 * This updates the p_sflag's for the checks below in one 167 * "atomic" operation with turning off the astpending flag. 168 * If another AST is triggered while we are handling the 169 * AST's saved in sflag, the astpending flag will be set and 170 * ast() will be called again. 171 */ 172 mtx_lock_spin(&sched_lock); 173 ke = td->td_kse; 174 sticks = td->td_sticks; 175 flags = td->td_flags; 176 sflag = p->p_sflag; 177 p->p_sflag &= ~(PS_ALRMPEND | PS_NEEDSIGCHK | PS_PROFPEND | PS_XCPU); 178#ifdef MAC 179 p->p_sflag &= ~PS_MACPEND; 180#endif 181 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDRESCHED | TDF_OWEUPC); 182 cnt.v_soft++; 183 prticks = 0; 184 if (flags & TDF_OWEUPC && sflag & PS_PROFIL) { 185 prticks = p->p_stats->p_prof.pr_ticks; 186 p->p_stats->p_prof.pr_ticks = 0; 187 } 188 mtx_unlock_spin(&sched_lock); 189 /* 190 * XXXKSE While the fact that we owe a user profiling 191 * tick is stored per KSE in this code, the statistics 192 * themselves are still stored per process. 193 * This should probably change, by which I mean that 194 * possibly the location of both might change. 195 */ 196 197 if (td->td_ucred != p->p_ucred) 198 cred_update_thread(td); 199 if (flags & TDF_OWEUPC && sflag & PS_PROFIL) 200 addupc_task(td, p->p_stats->p_prof.pr_addr, prticks); 201 if (sflag & PS_ALRMPEND) { 202 PROC_LOCK(p); 203 psignal(p, SIGVTALRM); 204 PROC_UNLOCK(p); 205 } 206#if defined(DEV_NPX) && !defined(SMP) 207 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 208 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags, 209 PCB_NPXTRAP); 210 ucode = npxtrap(); 211 if (ucode != -1) { 212 trapsignal(p, SIGFPE, ucode); 213 } 214 } 215#endif 216 if (sflag & PS_PROFPEND) { 217 PROC_LOCK(p); 218 psignal(p, SIGPROF); 219 PROC_UNLOCK(p); 220 } 221 if (sflag & PS_XCPU) { 222 PROC_LOCK(p); 223 rlim = &p->p_rlimit[RLIMIT_CPU]; 224 if (p->p_runtime.sec >= rlim->rlim_max) 225 killproc(p, "exceeded maximum CPU limit"); 226 else { 227 psignal(p, SIGXCPU); 228 mtx_lock_spin(&sched_lock); 229 if (p->p_cpulimit < rlim->rlim_max) 230 p->p_cpulimit += 5; 231 mtx_unlock_spin(&sched_lock); 232 } 233 PROC_UNLOCK(p); 234 } 235#ifdef MAC 236 if (sflag & PS_MACPEND) 237 mac_thread_userret(td); 238#endif 239 if (flags & TDF_NEEDRESCHED) { 240 mtx_lock_spin(&sched_lock); 241 sched_prio(td, kg->kg_user_pri); 242 p->p_stats->p_ru.ru_nivcsw++; 243 mi_switch(); 244 mtx_unlock_spin(&sched_lock); 245 } 246 if (sflag & PS_NEEDSIGCHK) { 247 int sigs; 248 249 sigs = 0; 250 PROC_LOCK(p); 251 while ((sig = cursig(td)) != 0) { 252 postsig(sig); 253 sigs++; 254 } 255 PROC_UNLOCK(p); 256 if (p->p_flag & P_THREADED && sigs) 257 thread_signal_upcall(td); 258 } 259 260 userret(td, framep, sticks); 261#ifdef DIAGNOSTIC 262 cred_free_thread(td); 263#endif 264 mtx_assert(&Giant, MA_NOTOWNED); 265} 266