subr_syscall.c revision 184042
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 184042 2008-10-19 01:35:27Z kmacy $"); 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#ifdef XEN 77#include <vm/vm.h> 78#include <vm/vm_param.h> 79#include <vm/pmap.h> 80#endif 81 82#include <security/mac/mac_framework.h> 83 84/* 85 * Define the code needed before returning to user mode, for trap and 86 * syscall. 87 */ 88void 89userret(struct thread *td, struct trapframe *frame) 90{ 91 struct proc *p = td->td_proc; 92 93 CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid, 94 td->td_name); 95#ifdef DIAGNOSTIC 96 /* Check that we called signotify() enough. */ 97 PROC_LOCK(p); 98 thread_lock(td); 99 if (SIGPENDING(td) && ((td->td_flags & TDF_NEEDSIGCHK) == 0 || 100 (td->td_flags & TDF_ASTPENDING) == 0)) 101 printf("failed to set signal flags properly for ast()\n"); 102 thread_unlock(td); 103 PROC_UNLOCK(p); 104#endif 105#ifdef KTRACE 106 KTRUSERRET(td); 107#endif 108 /* 109 * If this thread tickled GEOM, we need to wait for the giggling to 110 * stop before we return to userland 111 */ 112 if (td->td_pflags & TDP_GEOM) 113 g_waitidle(); 114 115 /* 116 * Charge system time if profiling. 117 */ 118 if (p->p_flag & P_PROFIL) { 119 addupc_task(td, TRAPF_PC(frame), td->td_pticks * psratio); 120 } 121 /* 122 * Let the scheduler adjust our priority etc. 123 */ 124 sched_userret(td); 125 KASSERT(td->td_locks == 0, 126 ("userret: Returning with %d locks held.", td->td_locks)); 127#ifdef XEN 128 PT_UPDATES_FLUSH(); 129#endif 130} 131 132/* 133 * Process an asynchronous software trap. 134 * This is relatively easy. 135 * This function will return with preemption disabled. 136 */ 137void 138ast(struct trapframe *framep) 139{ 140 struct thread *td; 141 struct proc *p; 142 int flags; 143 int sig; 144#if defined(DEV_NPX) && !defined(SMP) 145 int ucode; 146 ksiginfo_t ksi; 147#endif 148 149 td = curthread; 150 p = td->td_proc; 151 152 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 153 p->p_comm); 154 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 155 WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode"); 156 mtx_assert(&Giant, MA_NOTOWNED); 157 THREAD_LOCK_ASSERT(td, MA_NOTOWNED); 158 td->td_frame = framep; 159 td->td_pticks = 0; 160 161 /* 162 * This updates the td_flag's for the checks below in one 163 * "atomic" operation with turning off the astpending flag. 164 * If another AST is triggered while we are handling the 165 * AST's saved in flags, the astpending flag will be set and 166 * ast() will be called again. 167 */ 168 thread_lock(td); 169 flags = td->td_flags; 170 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | TDF_NEEDSUSPCHK | 171 TDF_NEEDRESCHED | TDF_ALRMPEND | TDF_PROFPEND | TDF_MACPEND); 172 thread_unlock(td); 173 PCPU_INC(cnt.v_trap); 174 175 if (td->td_ucred != p->p_ucred) 176 cred_update_thread(td); 177 if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) { 178 addupc_task(td, td->td_profil_addr, td->td_profil_ticks); 179 td->td_profil_ticks = 0; 180 td->td_pflags &= ~TDP_OWEUPC; 181 } 182#if defined(HWPMC_HOOKS) 183 if (td->td_pflags & TDP_CALLCHAIN) { 184 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_USER_CALLCHAIN, 185 (void *) framep); 186 td->td_pflags &= ~TDP_CALLCHAIN; 187 } 188#endif 189 if (flags & TDF_ALRMPEND) { 190 PROC_LOCK(p); 191 psignal(p, SIGVTALRM); 192 PROC_UNLOCK(p); 193 } 194#if defined(DEV_NPX) && !defined(SMP) 195 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 196 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags, 197 PCB_NPXTRAP); 198 ucode = npxtrap(); 199 if (ucode != -1) { 200 ksiginfo_init_trap(&ksi); 201 ksi.ksi_signo = SIGFPE; 202 ksi.ksi_code = ucode; 203 trapsignal(td, &ksi); 204 } 205 } 206#endif 207 if (flags & TDF_PROFPEND) { 208 PROC_LOCK(p); 209 psignal(p, SIGPROF); 210 PROC_UNLOCK(p); 211 } 212#ifdef MAC 213 if (flags & TDF_MACPEND) 214 mac_thread_userret(td); 215#endif 216 if (flags & TDF_NEEDRESCHED) { 217#ifdef KTRACE 218 if (KTRPOINT(td, KTR_CSW)) 219 ktrcsw(1, 1); 220#endif 221 thread_lock(td); 222 sched_prio(td, td->td_user_pri); 223 mi_switch(SW_INVOL | SWT_NEEDRESCHED, NULL); 224 thread_unlock(td); 225#ifdef KTRACE 226 if (KTRPOINT(td, KTR_CSW)) 227 ktrcsw(0, 1); 228#endif 229 } 230 if (flags & TDF_NEEDSIGCHK) { 231 PROC_LOCK(p); 232 mtx_lock(&p->p_sigacts->ps_mtx); 233 while ((sig = cursig(td)) != 0) 234 postsig(sig); 235 mtx_unlock(&p->p_sigacts->ps_mtx); 236 PROC_UNLOCK(p); 237 } 238 /* 239 * We need to check to see if we have to exit or wait due to a 240 * single threading requirement or some other STOP condition. 241 */ 242 if (flags & TDF_NEEDSUSPCHK) { 243 PROC_LOCK(p); 244 thread_suspend_check(0); 245 PROC_UNLOCK(p); 246 } 247 248 userret(td, framep); 249 mtx_assert(&Giant, MA_NOTOWNED); 250} 251