subr_syscall.c revision 177091
1/*- 2 * Copyright (C) 1994, David Greenman 3 * Copyright (c) 1990, 1993 4 * The Regents of the University of California. All rights reserved. 5 * Copyright (c) 2007 The FreeBSD Foundation 6 * 7 * This code is derived from software contributed to Berkeley by 8 * the University of Utah, and William Jolitz. 9 * 10 * Portions of this software were developed by A. Joseph Koshy under 11 * sponsorship from the FreeBSD Foundation and Google, Inc. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. All advertising materials mentioning features or use of this software 22 * must display the following acknowledgement: 23 * This product includes software developed by the University of 24 * California, Berkeley and its contributors. 25 * 4. Neither the name of the University nor the names of its contributors 26 * may be used to endorse or promote products derived from this software 27 * without specific prior written permission. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 32 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 39 * SUCH DAMAGE. 40 * 41 * from: @(#)trap.c 7.4 (Berkeley) 5/13/91 42 */ 43 44#include <sys/cdefs.h> 45__FBSDID("$FreeBSD: head/sys/kern/subr_trap.c 177091 2008-03-12 10:12:01Z jeff $"); 46 47#include "opt_hwpmc_hooks.h" 48#include "opt_ktrace.h" 49#include "opt_mac.h" 50#ifdef __i386__ 51#include "opt_npx.h" 52#endif 53#include "opt_sched.h" 54 55#include <sys/param.h> 56#include <sys/bus.h> 57#include <sys/kernel.h> 58#include <sys/lock.h> 59#include <sys/mutex.h> 60#include <sys/pmckern.h> 61#include <sys/proc.h> 62#include <sys/ktr.h> 63#include <sys/resourcevar.h> 64#include <sys/sched.h> 65#include <sys/signalvar.h> 66#include <sys/systm.h> 67#include <sys/vmmeter.h> 68#ifdef KTRACE 69#include <sys/uio.h> 70#include <sys/ktrace.h> 71#endif 72 73#include <machine/cpu.h> 74#include <machine/pcb.h> 75 76#include <security/mac/mac_framework.h> 77 78/* 79 * Define the code needed before returning to user mode, for trap and 80 * syscall. 81 */ 82void 83userret(struct thread *td, struct trapframe *frame) 84{ 85 struct proc *p = td->td_proc; 86 87 CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid, 88 td->td_name); 89#ifdef DIAGNOSTIC 90 /* Check that we called signotify() enough. */ 91 PROC_LOCK(p); 92 thread_lock(td); 93 if (SIGPENDING(td) && ((td->td_flags & TDF_NEEDSIGCHK) == 0 || 94 (td->td_flags & TDF_ASTPENDING) == 0)) 95 printf("failed to set signal flags properly for ast()\n"); 96 thread_unlock(td); 97 PROC_UNLOCK(p); 98#endif 99 100#ifdef KTRACE 101 KTRUSERRET(td); 102#endif 103 104 /* 105 * If this thread tickled GEOM, we need to wait for the giggling to 106 * stop before we return to userland 107 */ 108 if (td->td_pflags & TDP_GEOM) 109 g_waitidle(); 110 111 /* 112 * We need to check to see if we have to exit or wait due to a 113 * single threading requirement or some other STOP condition. 114 * Don't bother doing all the work if the stop bits are not set 115 * at this time.. If we miss it, we miss it.. no big deal. 116 */ 117 if (P_SHOULDSTOP(p)) { 118 PROC_LOCK(p); 119 thread_suspend_check(0); /* Can suspend or kill */ 120 PROC_UNLOCK(p); 121 } 122 /* 123 * Charge system time if profiling. 124 */ 125 if (p->p_flag & P_PROFIL) { 126 127 addupc_task(td, TRAPF_PC(frame), td->td_pticks * psratio); 128 } 129 /* 130 * Let the scheduler adjust our priority etc. 131 */ 132 sched_userret(td); 133 KASSERT(td->td_locks == 0, 134 ("userret: Returning with %d locks held.", td->td_locks)); 135} 136 137/* 138 * Process an asynchronous software trap. 139 * This is relatively easy. 140 * This function will return with preemption disabled. 141 */ 142void 143ast(struct trapframe *framep) 144{ 145 struct thread *td; 146 struct proc *p; 147 int flags; 148 int sig; 149#if defined(DEV_NPX) && !defined(SMP) 150 int ucode; 151 ksiginfo_t ksi; 152#endif 153 154 td = curthread; 155 p = td->td_proc; 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 THREAD_LOCK_ASSERT(td, MA_NOTOWNED); 163 td->td_frame = framep; 164 td->td_pticks = 0; 165 166 /* 167 * This updates the td_flag's for the checks below in one 168 * "atomic" operation with turning off the astpending flag. 169 * If another AST is triggered while we are handling the 170 * AST's saved in flags, the astpending flag will be set and 171 * ast() will be called again. 172 */ 173 thread_lock(td); 174 flags = td->td_flags; 175 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | 176 TDF_NEEDRESCHED | TDF_ALRMPEND | TDF_PROFPEND | 177 TDF_MACPEND); 178 thread_unlock(td); 179 PCPU_INC(cnt.v_trap); 180 181 if (td->td_ucred != p->p_ucred) 182 cred_update_thread(td); 183 if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) { 184 addupc_task(td, td->td_profil_addr, td->td_profil_ticks); 185 td->td_profil_ticks = 0; 186 td->td_pflags &= ~TDP_OWEUPC; 187 } 188#if defined(HWPMC_HOOKS) 189 if (td->td_pflags & TDP_CALLCHAIN) { 190 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_USER_CALLCHAIN, 191 (void *) framep); 192 td->td_pflags &= ~TDP_CALLCHAIN; 193 } 194#endif 195 if (flags & TDF_ALRMPEND) { 196 PROC_LOCK(p); 197 psignal(p, SIGVTALRM); 198 PROC_UNLOCK(p); 199 } 200#if defined(DEV_NPX) && !defined(SMP) 201 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 202 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags, 203 PCB_NPXTRAP); 204 ucode = npxtrap(); 205 if (ucode != -1) { 206 ksiginfo_init_trap(&ksi); 207 ksi.ksi_signo = SIGFPE; 208 ksi.ksi_code = ucode; 209 trapsignal(td, &ksi); 210 } 211 } 212#endif 213 if (flags & TDF_PROFPEND) { 214 PROC_LOCK(p); 215 psignal(p, SIGPROF); 216 PROC_UNLOCK(p); 217 } 218#ifdef MAC 219 if (flags & TDF_MACPEND) 220 mac_thread_userret(td); 221#endif 222 if (flags & TDF_NEEDRESCHED) { 223#ifdef KTRACE 224 if (KTRPOINT(td, KTR_CSW)) 225 ktrcsw(1, 1); 226#endif 227 thread_lock(td); 228 sched_prio(td, td->td_user_pri); 229 SCHED_STAT_INC(switch_needresched); 230 mi_switch(SW_INVOL, NULL); 231 thread_unlock(td); 232#ifdef KTRACE 233 if (KTRPOINT(td, KTR_CSW)) 234 ktrcsw(0, 1); 235#endif 236 } 237 if (flags & TDF_NEEDSIGCHK) { 238 PROC_LOCK(p); 239 mtx_lock(&p->p_sigacts->ps_mtx); 240 while ((sig = cursig(td)) != 0) 241 postsig(sig); 242 mtx_unlock(&p->p_sigacts->ps_mtx); 243 PROC_UNLOCK(p); 244 } 245 246 userret(td, framep); 247 mtx_assert(&Giant, MA_NOTOWNED); 248} 249