subr_syscall.c revision 170307
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 170307 2007-06-05 00:00:57Z jeff $"); 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/mutex.h> 54#include <sys/proc.h> 55#include <sys/ktr.h> 56#include <sys/resourcevar.h> 57#include <sys/sched.h> 58#include <sys/signalvar.h> 59#include <sys/systm.h> 60#include <sys/vmmeter.h> 61#ifdef KTRACE 62#include <sys/uio.h> 63#include <sys/ktrace.h> 64#endif 65 66#include <machine/cpu.h> 67#include <machine/pcb.h> 68 69#include <security/mac/mac_framework.h> 70 71/* 72 * Define the code needed before returning to user mode, for trap and 73 * syscall. 74 */ 75void 76userret(struct thread *td, struct trapframe *frame) 77{ 78 struct proc *p = td->td_proc; 79 80 CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid, 81 p->p_comm); 82#ifdef DIAGNOSTIC 83 /* Check that we called signotify() enough. */ 84 PROC_LOCK(p); 85 thread_lock(td); 86 if (SIGPENDING(td) && ((td->td_flags & TDF_NEEDSIGCHK) == 0 || 87 (td->td_flags & TDF_ASTPENDING) == 0)) 88 printf("failed to set signal flags properly for ast()\n"); 89 thread_unlock(td); 90 PROC_UNLOCK(p); 91#endif 92 93#ifdef KTRACE 94 KTRUSERRET(td); 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#ifdef KSE 117 /* 118 * Do special thread processing, e.g. upcall tweaking and such. 119 */ 120 if (p->p_flag & P_SA) 121 thread_userret(td, frame); 122#endif 123 124 /* 125 * Charge system time if profiling. 126 */ 127 if (p->p_flag & P_PROFIL) { 128 129 addupc_task(td, TRAPF_PC(frame), td->td_pticks * psratio); 130 } 131 132 /* 133 * Let the scheduler adjust our priority etc. 134 */ 135 sched_userret(td); 136 KASSERT(td->td_locks == 0, 137 ("userret: Returning with %d locks held.", td->td_locks)); 138} 139 140/* 141 * Process an asynchronous software trap. 142 * This is relatively easy. 143 * This function will return with preemption disabled. 144 */ 145void 146ast(struct trapframe *framep) 147{ 148 struct thread *td; 149 struct proc *p; 150 int sflag; 151 int flags; 152 int sig; 153#if defined(DEV_NPX) && !defined(SMP) 154 int ucode; 155 ksiginfo_t ksi; 156#endif 157 158 td = curthread; 159 p = td->td_proc; 160 161 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 162 p->p_comm); 163 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 164 WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode"); 165 mtx_assert(&Giant, MA_NOTOWNED); 166 THREAD_LOCK_ASSERT(td, MA_NOTOWNED); 167 td->td_frame = framep; 168 td->td_pticks = 0; 169 170#ifdef KSE 171 if ((p->p_flag & P_SA) && (td->td_mailbox == NULL)) 172 thread_user_enter(td); 173#endif 174 175 /* 176 * This updates the p_sflag's for the checks below in one 177 * "atomic" operation with turning off the astpending flag. 178 * If another AST is triggered while we are handling the 179 * AST's saved in sflag, the astpending flag will be set and 180 * ast() will be called again. 181 */ 182 PROC_SLOCK(p); 183 sflag = p->p_sflag; 184 if (p->p_sflag & (PS_ALRMPEND | PS_PROFPEND)) 185 p->p_sflag &= ~(PS_ALRMPEND | PS_PROFPEND); 186#ifdef MAC 187 if (p->p_sflag & PS_MACPEND) 188 p->p_sflag &= ~PS_MACPEND; 189#endif 190 thread_lock(td); 191 PROC_SUNLOCK(p); 192 flags = td->td_flags; 193 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | 194 TDF_NEEDRESCHED | TDF_INTERRUPT); 195 thread_unlock(td); 196 PCPU_INC(cnt.v_trap); 197 198 /* 199 * XXXKSE While the fact that we owe a user profiling 200 * tick is stored per thread in this code, the statistics 201 * themselves are still stored per process. 202 * This should probably change, by which I mean that 203 * possibly the location of both might change. 204 */ 205 if (td->td_ucred != p->p_ucred) 206 cred_update_thread(td); 207 if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) { 208 addupc_task(td, td->td_profil_addr, td->td_profil_ticks); 209 td->td_profil_ticks = 0; 210 td->td_pflags &= ~TDP_OWEUPC; 211 } 212 if (sflag & PS_ALRMPEND) { 213 PROC_LOCK(p); 214 psignal(p, SIGVTALRM); 215 PROC_UNLOCK(p); 216 } 217#if defined(DEV_NPX) && !defined(SMP) 218 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 219 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags, 220 PCB_NPXTRAP); 221 ucode = npxtrap(); 222 if (ucode != -1) { 223 ksiginfo_init_trap(&ksi); 224 ksi.ksi_signo = SIGFPE; 225 ksi.ksi_code = ucode; 226 trapsignal(td, &ksi); 227 } 228 } 229#endif 230 if (sflag & PS_PROFPEND) { 231 PROC_LOCK(p); 232 psignal(p, SIGPROF); 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#ifdef KTRACE 241 if (KTRPOINT(td, KTR_CSW)) 242 ktrcsw(1, 1); 243#endif 244 thread_lock(td); 245 sched_prio(td, td->td_user_pri); 246 SCHED_STAT_INC(switch_needresched); 247 mi_switch(SW_INVOL, NULL); 248 thread_unlock(td); 249#ifdef KTRACE 250 if (KTRPOINT(td, KTR_CSW)) 251 ktrcsw(0, 1); 252#endif 253 } 254 if (flags & TDF_NEEDSIGCHK) { 255 PROC_LOCK(p); 256 mtx_lock(&p->p_sigacts->ps_mtx); 257 while ((sig = cursig(td)) != 0) 258 postsig(sig); 259 mtx_unlock(&p->p_sigacts->ps_mtx); 260 PROC_UNLOCK(p); 261 } 262 263 userret(td, framep); 264 mtx_assert(&Giant, MA_NOTOWNED); 265} 266