subr_syscall.c revision 193511
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 193511 2009-06-05 14:55:22Z rwatson $"); 46 47#include "opt_ktrace.h" 48#ifdef __i386__ 49#include "opt_npx.h" 50#endif 51#include "opt_sched.h" 52 53#include <sys/param.h> 54#include <sys/bus.h> 55#include <sys/kernel.h> 56#include <sys/lock.h> 57#include <sys/mutex.h> 58#include <sys/pmckern.h> 59#include <sys/proc.h> 60#include <sys/ktr.h> 61#include <sys/resourcevar.h> 62#include <sys/sched.h> 63#include <sys/signalvar.h> 64#include <sys/systm.h> 65#include <sys/vmmeter.h> 66#ifdef KTRACE 67#include <sys/uio.h> 68#include <sys/ktrace.h> 69#endif 70 71#include <machine/cpu.h> 72#include <machine/pcb.h> 73 74#ifdef XEN 75#include <vm/vm.h> 76#include <vm/vm_param.h> 77#include <vm/pmap.h> 78#endif 79 80#include <security/mac/mac_framework.h> 81 82/* 83 * Define the code needed before returning to user mode, for trap and 84 * syscall. 85 */ 86void 87userret(struct thread *td, struct trapframe *frame) 88{ 89 struct proc *p = td->td_proc; 90 91 CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid, 92 td->td_name); 93#ifdef DIAGNOSTIC 94 /* Check that we called signotify() enough. */ 95 PROC_LOCK(p); 96 thread_lock(td); 97 if (SIGPENDING(td) && ((td->td_flags & TDF_NEEDSIGCHK) == 0 || 98 (td->td_flags & TDF_ASTPENDING) == 0)) 99 printf("failed to set signal flags properly for ast()\n"); 100 thread_unlock(td); 101 PROC_UNLOCK(p); 102#endif 103#ifdef KTRACE 104 KTRUSERRET(td); 105#endif 106 /* 107 * If this thread tickled GEOM, we need to wait for the giggling to 108 * stop before we return to userland 109 */ 110 if (td->td_pflags & TDP_GEOM) 111 g_waitidle(); 112 113 /* 114 * Charge system time if profiling. 115 */ 116 if (p->p_flag & P_PROFIL) { 117 addupc_task(td, TRAPF_PC(frame), td->td_pticks * psratio); 118 } 119 /* 120 * Let the scheduler adjust our priority etc. 121 */ 122 sched_userret(td); 123 KASSERT(td->td_locks == 0, 124 ("userret: Returning with %d locks held.", td->td_locks)); 125#ifdef XEN 126 PT_UPDATES_FLUSH(); 127#endif 128} 129 130/* 131 * Process an asynchronous software trap. 132 * This is relatively easy. 133 * This function will return with preemption disabled. 134 */ 135void 136ast(struct trapframe *framep) 137{ 138 struct thread *td; 139 struct proc *p; 140 int flags; 141 int sig; 142#if defined(DEV_NPX) && !defined(SMP) 143 int ucode; 144 ksiginfo_t ksi; 145#endif 146 147 td = curthread; 148 p = td->td_proc; 149 150 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 151 p->p_comm); 152 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 153 WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode"); 154 mtx_assert(&Giant, MA_NOTOWNED); 155 THREAD_LOCK_ASSERT(td, MA_NOTOWNED); 156 td->td_frame = framep; 157 td->td_pticks = 0; 158 159 /* 160 * This updates the td_flag's for the checks below in one 161 * "atomic" operation with turning off the astpending flag. 162 * If another AST is triggered while we are handling the 163 * AST's saved in flags, the astpending flag will be set and 164 * ast() will be called again. 165 */ 166 thread_lock(td); 167 flags = td->td_flags; 168 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | TDF_NEEDSUSPCHK | 169 TDF_NEEDRESCHED | TDF_ALRMPEND | TDF_PROFPEND | TDF_MACPEND); 170 thread_unlock(td); 171 PCPU_INC(cnt.v_trap); 172 173 if (td->td_ucred != p->p_ucred) 174 cred_update_thread(td); 175 if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) { 176 addupc_task(td, td->td_profil_addr, td->td_profil_ticks); 177 td->td_profil_ticks = 0; 178 td->td_pflags &= ~TDP_OWEUPC; 179 } 180 if (flags & TDF_ALRMPEND) { 181 PROC_LOCK(p); 182 psignal(p, SIGVTALRM); 183 PROC_UNLOCK(p); 184 } 185#if defined(DEV_NPX) && !defined(SMP) 186 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 187 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags, 188 PCB_NPXTRAP); 189 ucode = npxtrap(); 190 if (ucode != -1) { 191 ksiginfo_init_trap(&ksi); 192 ksi.ksi_signo = SIGFPE; 193 ksi.ksi_code = ucode; 194 trapsignal(td, &ksi); 195 } 196 } 197#endif 198 if (flags & TDF_PROFPEND) { 199 PROC_LOCK(p); 200 psignal(p, SIGPROF); 201 PROC_UNLOCK(p); 202 } 203#ifdef MAC 204 if (flags & TDF_MACPEND) 205 mac_thread_userret(td); 206#endif 207 if (flags & TDF_NEEDRESCHED) { 208#ifdef KTRACE 209 if (KTRPOINT(td, KTR_CSW)) 210 ktrcsw(1, 1); 211#endif 212 thread_lock(td); 213 sched_prio(td, td->td_user_pri); 214 mi_switch(SW_INVOL | SWT_NEEDRESCHED, NULL); 215 thread_unlock(td); 216#ifdef KTRACE 217 if (KTRPOINT(td, KTR_CSW)) 218 ktrcsw(0, 1); 219#endif 220 } 221 if (flags & TDF_NEEDSIGCHK) { 222 PROC_LOCK(p); 223 mtx_lock(&p->p_sigacts->ps_mtx); 224 while ((sig = cursig(td)) != 0) 225 postsig(sig); 226 mtx_unlock(&p->p_sigacts->ps_mtx); 227 PROC_UNLOCK(p); 228 } 229 /* 230 * We need to check to see if we have to exit or wait due to a 231 * single threading requirement or some other STOP condition. 232 */ 233 if (flags & TDF_NEEDSUSPCHK) { 234 PROC_LOCK(p); 235 thread_suspend_check(0); 236 PROC_UNLOCK(p); 237 } 238 239 userret(td, framep); 240 mtx_assert(&Giant, MA_NOTOWNED); 241} 242