subr_syscall.c revision 110190
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 110190 2003-02-01 12:17:09Z julian $ 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 struct kse *ke = td->td_kse; 77 78 CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid, 79 p->p_comm); 80#ifdef INVARIANTS 81 /* Check that we called signotify() enough. */ 82 mtx_lock(&Giant); 83 PROC_LOCK(p); 84 mtx_lock_spin(&sched_lock); 85 if (SIGPENDING(p) && ((p->p_sflag & PS_NEEDSIGCHK) == 0 || 86 (td->td_kse->ke_flags & KEF_ASTPENDING) == 0)) 87 printf("failed to set signal flags properly for ast()\n"); 88 mtx_unlock_spin(&sched_lock); 89 PROC_UNLOCK(p); 90 mtx_unlock(&Giant); 91#endif 92 93 /* 94 * Let the scheduler adjust our priority etc. 95 */ 96 sched_userret(td); 97 98 /* 99 * We need to check to see if we have to exit or wait due to a 100 * single threading requirement or some other STOP condition. 101 * Don't bother doing all the work if the stop bits are not set 102 * at this time.. If we miss it, we miss it.. no big deal. 103 */ 104 if (P_SHOULDSTOP(p)) { 105 PROC_LOCK(p); 106 thread_suspend_check(0); /* Can suspend or kill */ 107 PROC_UNLOCK(p); 108 } 109 110 /* 111 * Do special thread processing, e.g. upcall tweaking and such. 112 */ 113 if (p->p_flag & P_KSES) { 114 thread_userret(td, frame); 115 } 116 117 /* 118 * Charge system time if profiling. 119 * 120 * XXX should move PS_PROFIL to a place that can obviously be 121 * accessed safely without sched_lock. 122 */ 123 if (p->p_sflag & PS_PROFIL) { 124 quad_t ticks; 125 126 mtx_lock_spin(&sched_lock); 127 ticks = ke->ke_sticks - oticks; 128 mtx_unlock_spin(&sched_lock); 129 addupc_task(ke, TRAPF_PC(frame), (u_int)ticks * psratio); 130 } 131} 132 133/* 134 * Process an asynchronous software trap. 135 * This is relatively easy. 136 * This function will return with preemption disabled. 137 */ 138void 139ast(struct trapframe *framep) 140{ 141 struct thread *td; 142 struct proc *p; 143 struct kse *ke; 144 struct ksegrp *kg; 145 struct rlimit *rlim; 146 u_int prticks, sticks; 147 int sflag; 148 int flags; 149 int sig; 150#if defined(DEV_NPX) && !defined(SMP) 151 int ucode; 152#endif 153 154 td = curthread; 155 p = td->td_proc; 156 kg = td->td_ksegrp; 157 158 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 159 p->p_comm); 160 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 161#ifdef WITNESS 162 if (witness_list(td)) 163 panic("Returning to user mode with mutex(s) held"); 164#endif 165 mtx_assert(&Giant, MA_NOTOWNED); 166 mtx_assert(&sched_lock, MA_NOTOWNED); 167 td->td_frame = framep; 168 169 /* 170 * This updates the p_sflag's for the checks below in one 171 * "atomic" operation with turning off the astpending flag. 172 * If another AST is triggered while we are handling the 173 * AST's saved in sflag, the astpending flag will be set and 174 * ast() will be called again. 175 */ 176 mtx_lock_spin(&sched_lock); 177 ke = td->td_kse; 178 sticks = ke->ke_sticks; 179 flags = ke->ke_flags; 180 sflag = p->p_sflag; 181 p->p_sflag &= ~(PS_ALRMPEND | PS_NEEDSIGCHK | PS_PROFPEND | PS_XCPU); 182#ifdef MAC 183 p->p_sflag &= ~PS_MACPEND; 184#endif 185 ke->ke_flags &= ~(KEF_ASTPENDING | KEF_NEEDRESCHED | KEF_OWEUPC); 186 cnt.v_soft++; 187 prticks = 0; 188 if (flags & KEF_OWEUPC && sflag & PS_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 & KEF_OWEUPC && sflag & PS_PROFIL) 204 addupc_task(ke, 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(p, 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 if (p->p_runtime.sec >= rlim->rlim_max) 229 killproc(p, "exceeded maximum CPU limit"); 230 else { 231 psignal(p, SIGXCPU); 232 mtx_lock_spin(&sched_lock); 233 if (p->p_cpulimit < rlim->rlim_max) 234 p->p_cpulimit += 5; 235 mtx_unlock_spin(&sched_lock); 236 } 237 PROC_UNLOCK(p); 238 } 239#ifdef MAC 240 if (sflag & PS_MACPEND) 241 mac_thread_userret(td); 242#endif 243 if (flags & KEF_NEEDRESCHED) { 244 mtx_lock_spin(&sched_lock); 245 sched_prio(td, kg->kg_user_pri); 246 p->p_stats->p_ru.ru_nivcsw++; 247 mi_switch(); 248 mtx_unlock_spin(&sched_lock); 249 } 250 if (sflag & PS_NEEDSIGCHK) { 251 PROC_LOCK(p); 252 while ((sig = cursig(td)) != 0) 253 postsig(sig); 254 PROC_UNLOCK(p); 255 } 256 257 userret(td, framep, sticks); 258#ifdef DIAGNOSTIC 259 cred_free_thread(td); 260#endif 261 mtx_assert(&Giant, MA_NOTOWNED); 262} 263