subr_syscall.c revision 113874
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 113874 2003-04-22 20:54:04Z 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(td) && ((td->td_flags & TDF_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 if (p->p_flag & P_PROFIL) { 120 quad_t ticks; 121 122 mtx_lock_spin(&sched_lock); 123 ticks = td->td_sticks - oticks; 124 mtx_unlock_spin(&sched_lock); 125 addupc_task(td, TRAPF_PC(frame), (u_int)ticks * psratio); 126 } 127} 128 129/* 130 * Process an asynchronous software trap. 131 * This is relatively easy. 132 * This function will return with preemption disabled. 133 */ 134void 135ast(struct trapframe *framep) 136{ 137 struct thread *td; 138 struct proc *p; 139 struct kse *ke; 140 struct ksegrp *kg; 141 struct rlimit *rlim; 142 u_int prticks, sticks; 143 int sflag; 144 int flags; 145 int sig; 146#if defined(DEV_NPX) && !defined(SMP) 147 int ucode; 148#endif 149 150 td = curthread; 151 p = td->td_proc; 152 kg = td->td_ksegrp; 153 154 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 155 p->p_comm); 156 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 157 WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode"); 158 mtx_assert(&Giant, MA_NOTOWNED); 159 mtx_assert(&sched_lock, MA_NOTOWNED); 160 td->td_frame = framep; 161 162 /* 163 * This updates the p_sflag's for the checks below in one 164 * "atomic" operation with turning off the astpending flag. 165 * If another AST is triggered while we are handling the 166 * AST's saved in sflag, the astpending flag will be set and 167 * ast() will be called again. 168 */ 169 mtx_lock_spin(&sched_lock); 170 ke = td->td_kse; 171 sticks = td->td_sticks; 172 flags = td->td_flags; 173 sflag = p->p_sflag; 174 p->p_sflag &= ~(PS_ALRMPEND | PS_PROFPEND | PS_XCPU); 175#ifdef MAC 176 p->p_sflag &= ~PS_MACPEND; 177#endif 178 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | 179 TDF_NEEDRESCHED | TDF_OWEUPC); 180 cnt.v_soft++; 181 prticks = 0; 182 if (flags & TDF_OWEUPC && p->p_flag & P_PROFIL) { 183 prticks = p->p_stats->p_prof.pr_ticks; 184 p->p_stats->p_prof.pr_ticks = 0; 185 } 186 mtx_unlock_spin(&sched_lock); 187 /* 188 * XXXKSE While the fact that we owe a user profiling 189 * tick is stored per KSE in this code, the statistics 190 * themselves are still stored per process. 191 * This should probably change, by which I mean that 192 * possibly the location of both might change. 193 */ 194 195 if (td->td_ucred != p->p_ucred) 196 cred_update_thread(td); 197 if (flags & TDF_OWEUPC && p->p_flag & P_PROFIL) 198 addupc_task(td, p->p_stats->p_prof.pr_addr, prticks); 199 if (sflag & PS_ALRMPEND) { 200 PROC_LOCK(p); 201 psignal(p, SIGVTALRM); 202 PROC_UNLOCK(p); 203 } 204#if defined(DEV_NPX) && !defined(SMP) 205 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 206 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags, 207 PCB_NPXTRAP); 208 ucode = npxtrap(); 209 if (ucode != -1) { 210 trapsignal(td, SIGFPE, ucode); 211 } 212 } 213#endif 214 if (sflag & PS_PROFPEND) { 215 PROC_LOCK(p); 216 psignal(p, SIGPROF); 217 PROC_UNLOCK(p); 218 } 219 if (sflag & PS_XCPU) { 220 PROC_LOCK(p); 221 rlim = &p->p_rlimit[RLIMIT_CPU]; 222 mtx_lock_spin(&sched_lock); 223 if (p->p_runtime.sec >= rlim->rlim_max) { 224 mtx_unlock_spin(&sched_lock); 225 killproc(p, "exceeded maximum CPU limit"); 226 } else { 227 if (p->p_cpulimit < rlim->rlim_max) 228 p->p_cpulimit += 5; 229 mtx_unlock_spin(&sched_lock); 230 psignal(p, SIGXCPU); 231 } 232 PROC_UNLOCK(p); 233 } 234#ifdef MAC 235 if (sflag & PS_MACPEND) 236 mac_thread_userret(td); 237#endif 238 if (flags & TDF_NEEDRESCHED) { 239 mtx_lock_spin(&sched_lock); 240 sched_prio(td, kg->kg_user_pri); 241 p->p_stats->p_ru.ru_nivcsw++; 242 mi_switch(); 243 mtx_unlock_spin(&sched_lock); 244 } 245 if (flags & TDF_NEEDSIGCHK) { 246 int sigs; 247 248 sigs = 0; 249 PROC_LOCK(p); 250 while ((sig = cursig(td)) != 0) { 251 postsig(sig); 252 sigs++; 253 } 254 PROC_UNLOCK(p); 255 if (p->p_flag & P_THREADED && sigs) { 256 struct kse_upcall *ku = td->td_upcall; 257 if ((void *)TRAPF_PC(framep) != ku->ku_func) { 258 mtx_lock_spin(&sched_lock); 259 ku->ku_flags |= KUF_DOUPCALL; 260 mtx_unlock_spin(&sched_lock); 261 } 262 } 263 } 264 265 userret(td, framep, sticks); 266#ifdef DIAGNOSTIC 267 cred_free_thread(td); 268#endif 269 mtx_assert(&Giant, MA_NOTOWNED); 270} 271