subr_syscall.c revision 186037
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 186037 2008-12-13 13:07:12Z jkoshy $"); 46 47#include "opt_ktrace.h" 48#include "opt_mac.h" 49#ifdef __i386__ 50#include "opt_npx.h" 51#endif 52#include "opt_sched.h" 53 54#include <sys/param.h> 55#include <sys/bus.h> 56#include <sys/kernel.h> 57#include <sys/lock.h> 58#include <sys/mutex.h> 59#include <sys/pmckern.h> 60#include <sys/proc.h> 61#include <sys/ktr.h> 62#include <sys/resourcevar.h> 63#include <sys/sched.h> 64#include <sys/signalvar.h> 65#include <sys/systm.h> 66#include <sys/vmmeter.h> 67#ifdef KTRACE 68#include <sys/uio.h> 69#include <sys/ktrace.h> 70#endif 71 72#include <machine/cpu.h> 73#include <machine/pcb.h> 74 75#ifdef XEN 76#include <vm/vm.h> 77#include <vm/vm_param.h> 78#include <vm/pmap.h> 79#endif 80 81#include <security/mac/mac_framework.h> 82 83/* 84 * Define the code needed before returning to user mode, for trap and 85 * syscall. 86 */ 87void 88userret(struct thread *td, struct trapframe *frame) 89{ 90 struct proc *p = td->td_proc; 91 92 CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid, 93 td->td_name); 94#ifdef DIAGNOSTIC 95 /* Check that we called signotify() enough. */ 96 PROC_LOCK(p); 97 thread_lock(td); 98 if (SIGPENDING(td) && ((td->td_flags & TDF_NEEDSIGCHK) == 0 || 99 (td->td_flags & TDF_ASTPENDING) == 0)) 100 printf("failed to set signal flags properly for ast()\n"); 101 thread_unlock(td); 102 PROC_UNLOCK(p); 103#endif 104#ifdef KTRACE 105 KTRUSERRET(td); 106#endif 107 /* 108 * If this thread tickled GEOM, we need to wait for the giggling to 109 * stop before we return to userland 110 */ 111 if (td->td_pflags & TDP_GEOM) 112 g_waitidle(); 113 114 /* 115 * Charge system time if profiling. 116 */ 117 if (p->p_flag & P_PROFIL) { 118 addupc_task(td, TRAPF_PC(frame), td->td_pticks * psratio); 119 } 120 /* 121 * Let the scheduler adjust our priority etc. 122 */ 123 sched_userret(td); 124 KASSERT(td->td_locks == 0, 125 ("userret: Returning with %d locks held.", td->td_locks)); 126#ifdef XEN 127 PT_UPDATES_FLUSH(); 128#endif 129} 130 131/* 132 * Process an asynchronous software trap. 133 * This is relatively easy. 134 * This function will return with preemption disabled. 135 */ 136void 137ast(struct trapframe *framep) 138{ 139 struct thread *td; 140 struct proc *p; 141 int flags; 142 int sig; 143#if defined(DEV_NPX) && !defined(SMP) 144 int ucode; 145 ksiginfo_t ksi; 146#endif 147 148 td = curthread; 149 p = td->td_proc; 150 151 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 152 p->p_comm); 153 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 154 WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode"); 155 mtx_assert(&Giant, MA_NOTOWNED); 156 THREAD_LOCK_ASSERT(td, MA_NOTOWNED); 157 td->td_frame = framep; 158 td->td_pticks = 0; 159 160 /* 161 * This updates the td_flag's for the checks below in one 162 * "atomic" operation with turning off the astpending flag. 163 * If another AST is triggered while we are handling the 164 * AST's saved in flags, the astpending flag will be set and 165 * ast() will be called again. 166 */ 167 thread_lock(td); 168 flags = td->td_flags; 169 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | TDF_NEEDSUSPCHK | 170 TDF_NEEDRESCHED | TDF_ALRMPEND | TDF_PROFPEND | TDF_MACPEND); 171 thread_unlock(td); 172 PCPU_INC(cnt.v_trap); 173 174 if (td->td_ucred != p->p_ucred) 175 cred_update_thread(td); 176 if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) { 177 addupc_task(td, td->td_profil_addr, td->td_profil_ticks); 178 td->td_profil_ticks = 0; 179 td->td_pflags &= ~TDP_OWEUPC; 180 } 181 if (flags & TDF_ALRMPEND) { 182 PROC_LOCK(p); 183 psignal(p, SIGVTALRM); 184 PROC_UNLOCK(p); 185 } 186#if defined(DEV_NPX) && !defined(SMP) 187 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 188 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags, 189 PCB_NPXTRAP); 190 ucode = npxtrap(); 191 if (ucode != -1) { 192 ksiginfo_init_trap(&ksi); 193 ksi.ksi_signo = SIGFPE; 194 ksi.ksi_code = ucode; 195 trapsignal(td, &ksi); 196 } 197 } 198#endif 199 if (flags & TDF_PROFPEND) { 200 PROC_LOCK(p); 201 psignal(p, SIGPROF); 202 PROC_UNLOCK(p); 203 } 204#ifdef MAC 205 if (flags & TDF_MACPEND) 206 mac_thread_userret(td); 207#endif 208 if (flags & TDF_NEEDRESCHED) { 209#ifdef KTRACE 210 if (KTRPOINT(td, KTR_CSW)) 211 ktrcsw(1, 1); 212#endif 213 thread_lock(td); 214 sched_prio(td, td->td_user_pri); 215 mi_switch(SW_INVOL | SWT_NEEDRESCHED, NULL); 216 thread_unlock(td); 217#ifdef KTRACE 218 if (KTRPOINT(td, KTR_CSW)) 219 ktrcsw(0, 1); 220#endif 221 } 222 if (flags & TDF_NEEDSIGCHK) { 223 PROC_LOCK(p); 224 mtx_lock(&p->p_sigacts->ps_mtx); 225 while ((sig = cursig(td)) != 0) 226 postsig(sig); 227 mtx_unlock(&p->p_sigacts->ps_mtx); 228 PROC_UNLOCK(p); 229 } 230 /* 231 * We need to check to see if we have to exit or wait due to a 232 * single threading requirement or some other STOP condition. 233 */ 234 if (flags & TDF_NEEDSUSPCHK) { 235 PROC_LOCK(p); 236 thread_suspend_check(0); 237 PROC_UNLOCK(p); 238 } 239 240 userret(td, framep); 241 mtx_assert(&Giant, MA_NOTOWNED); 242} 243