subr_syscall.c revision 132266
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 132266 2004-07-16 21:04:55Z 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 * Let the scheduler adjust our priority etc. 99 */ 100 sched_userret(td); 101 102 /* 103 * We need to check to see if we have to exit or wait due to a 104 * single threading requirement or some other STOP condition. 105 * Don't bother doing all the work if the stop bits are not set 106 * at this time.. If we miss it, we miss it.. no big deal. 107 */ 108 if (P_SHOULDSTOP(p)) { 109 PROC_LOCK(p); 110 thread_suspend_check(0); /* Can suspend or kill */ 111 PROC_UNLOCK(p); 112 } 113 114 /* 115 * Do special thread processing, e.g. upcall tweaking and such. 116 */ 117 if (p->p_flag & P_SA) 118 thread_userret(td, frame); 119 120 /* 121 * Charge system time if profiling. 122 */ 123 if (p->p_flag & P_PROFIL) { 124 quad_t ticks; 125 126 mtx_lock_spin(&sched_lock); 127 ticks = td->td_sticks - oticks; 128 mtx_unlock_spin(&sched_lock); 129 addupc_task(td, 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 ksegrp *kg; 144 struct rlimit rlim; 145 u_int 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 sticks = td->td_sticks; 174 flags = td->td_flags; 175 sflag = p->p_sflag; 176 p->p_sflag &= ~(PS_ALRMPEND | PS_PROFPEND | PS_XCPU); 177#ifdef MAC 178 p->p_sflag &= ~PS_MACPEND; 179#endif 180 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | 181 TDF_NEEDRESCHED | TDF_INTERRUPT); 182 cnt.v_soft++; 183 mtx_unlock_spin(&sched_lock); 184 /* 185 * XXXKSE While the fact that we owe a user profiling 186 * tick is stored per KSE in this code, the statistics 187 * themselves are still stored per process. 188 * This should probably change, by which I mean that 189 * possibly the location of both might change. 190 */ 191 192 if (td->td_ucred != p->p_ucred) 193 cred_update_thread(td); 194 if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) { 195 addupc_task(td, td->td_profil_addr, td->td_profil_ticks); 196 td->td_profil_ticks = 0; 197 td->td_pflags &= ~TDP_OWEUPC; 198 } 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 lim_rlimit(p, RLIMIT_CPU, &rlim); 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#ifdef KTRACE 240 if (KTRPOINT(td, KTR_CSW)) 241 ktrcsw(1, 1); 242#endif 243 mtx_lock_spin(&sched_lock); 244 sched_prio(td, kg->kg_user_pri); 245 mi_switch(SW_INVOL, NULL); 246 mtx_unlock_spin(&sched_lock); 247#ifdef KTRACE 248 if (KTRPOINT(td, KTR_CSW)) 249 ktrcsw(0, 1); 250#endif 251 } 252 if (flags & TDF_NEEDSIGCHK) { 253 PROC_LOCK(p); 254 mtx_lock(&p->p_sigacts->ps_mtx); 255 while ((sig = cursig(td)) != 0) 256 postsig(sig); 257 mtx_unlock(&p->p_sigacts->ps_mtx); 258 PROC_UNLOCK(p); 259 } 260 261 userret(td, framep, sticks); 262#ifdef DIAGNOSTIC 263 cred_free_thread(td); 264#endif 265 mtx_assert(&Giant, MA_NOTOWNED); 266} 267