Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_trap.c
Version:
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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("$FreeBSD$"); 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/mac.h> 54 #include <sys/mutex.h> 55 #include <sys/proc.h> 56 #include <sys/ktr.h> 57 #include <sys/resourcevar.h> 58 #include <sys/sched.h> 59 #include <sys/signalvar.h> 60 #include <sys/systm.h> 61 #include <sys/vmmeter.h> 62 #ifdef KTRACE 63 #include <sys/uio.h> 64 #include <sys/ktrace.h> 65 #endif 66 67 #include <machine/cpu.h> 68 #include <machine/pcb.h> 69 70 /* 71 * Define the code needed before returning to user mode, for 72 * trap and syscall. 73 * 74 * MPSAFE 75 */ 76 void 77 userret(td, frame, oticks) 78 struct thread *td; 79 struct trapframe *frame; 80 u_int oticks; 81 { 82 struct proc *p = td->td_proc; 83 84 CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid, 85 p->p_comm); 86 #ifdef DIAGNOSTIC 87 /* Check that we called signotify() enough. */ 88 PROC_LOCK(p); 89 mtx_lock_spin(&sched_lock); 90 if (SIGPENDING(td) && ((td->td_flags & TDF_NEEDSIGCHK) == 0 || 91 (td->td_flags & TDF_ASTPENDING) == 0)) 92 printf("failed to set signal flags properly for ast()\n"); 93 mtx_unlock_spin(&sched_lock); 94 PROC_UNLOCK(p); 95 #endif 96 97 #ifdef KTRACE 98 KTRUSERRET(td); 99 #endif 100 101 /* 102 * If this thread tickled GEOM, we need to wait for the giggling to 103 * stop before we return to userland 104 */ 105 if (td->td_pflags & TDP_GEOM) 106 g_waitidle(); 107 108 /* 109 * We need to check to see if we have to exit or wait due to a 110 * single threading requirement or some other STOP condition. 111 * Don't bother doing all the work if the stop bits are not set 112 * at this time.. If we miss it, we miss it.. no big deal. 113 */ 114 if (P_SHOULDSTOP(p)) { 115 PROC_LOCK(p); 116 thread_suspend_check(0); /* Can suspend or kill */ 117 PROC_UNLOCK(p); 118 } 119 120 /* 121 * Do special thread processing, e.g. upcall tweaking and such. 122 */ 123 if (p->p_flag & P_SA) 124 thread_userret(td, frame); 125 126 /* 127 * Charge system time if profiling. 128 */ 129 if (p->p_flag & P_PROFIL) { 130 quad_t ticks; 131 132 ticks = td->td_sticks - oticks; 133 addupc_task(td, TRAPF_PC(frame), (u_int)ticks * psratio); 134 } 135 136 /* 137 * Let the scheduler adjust our priority etc. 138 */ 139 sched_userret(td); 140 KASSERT(td->td_locks == 0, 141 ("userret: Returning with %d locks held.", td->td_locks)); 142 } 143 144 /* 145 * Process an asynchronous software trap. 146 * This is relatively easy. 147 * This function will return with preemption disabled. 148 */ 149 void 150 ast(struct trapframe *framep) 151 { 152 struct thread *td; 153 struct proc *p; 154 struct ksegrp *kg; 155 struct rlimit rlim; 156 u_int sticks; 157 int sflag; 158 int flags; 159 int sig; 160 #if defined(DEV_NPX) && !defined(SMP) 161 int ucode; 162 #endif 163 164 td = curthread; 165 p = td->td_proc; 166 kg = td->td_ksegrp; 167 168 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid, 169 p->p_comm); 170 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 171 WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode"); 172 mtx_assert(&Giant, MA_NOTOWNED); 173 mtx_assert(&sched_lock, MA_NOTOWNED); 174 td->td_frame = framep; 175 sticks = td->td_sticks; 176 177 if ((p->p_flag & P_SA) && (td->td_mailbox == NULL)) 178 thread_user_enter(td); 179 180 /* 181 * This updates the p_sflag's for the checks below in one 182 * "atomic" operation with turning off the astpending flag. 183 * If another AST is triggered while we are handling the 184 * AST's saved in sflag, the astpending flag will be set and 185 * ast() will be called again. 186 */ 187 mtx_lock_spin(&sched_lock); 188 flags = td->td_flags; 189 sflag = p->p_sflag; 190 p->p_sflag &= ~(PS_ALRMPEND | PS_PROFPEND | PS_XCPU); 191 #ifdef MAC 192 p->p_sflag &= ~PS_MACPEND; 193 #endif 194 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | 195 TDF_NEEDRESCHED | TDF_INTERRUPT); 196 cnt.v_soft++; 197 mtx_unlock_spin(&sched_lock); 198 199 /* 200 * XXXKSE While the fact that we owe a user profiling 201 * tick is stored per KSE in this code, the statistics 202 * themselves are still stored per process. 203 * This should probably change, by which I mean that 204 * possibly the location of both might change. 205 */ 206 if (td->td_ucred != p->p_ucred) 207 cred_update_thread(td); 208 if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) { 209 addupc_task(td, td->td_profil_addr, td->td_profil_ticks); 210 td->td_profil_ticks = 0; 211 td->td_pflags &= ~TDP_OWEUPC; 212 } 213 if (sflag & PS_ALRMPEND) { 214 PROC_LOCK(p); 215 psignal(p, SIGVTALRM); 216 PROC_UNLOCK(p); 217 } 218 #if defined(DEV_NPX) && !defined(SMP) 219 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) { 220 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags, 221 PCB_NPXTRAP); 222 ucode = npxtrap(); 223 if (ucode != -1) { 224 trapsignal(td, SIGFPE, ucode); 225 } 226 } 227 #endif 228 if (sflag & PS_PROFPEND) { 229 PROC_LOCK(p); 230 psignal(p, SIGPROF); 231 PROC_UNLOCK(p); 232 } 233 if (sflag & PS_XCPU) { 234 PROC_LOCK(p); 235 lim_rlimit(p, RLIMIT_CPU, &rlim); 236 mtx_lock_spin(&sched_lock); 237 if (p->p_rux.rux_runtime.sec >= rlim.rlim_max) { 238 mtx_unlock_spin(&sched_lock); 239 killproc(p, "exceeded maximum CPU limit"); 240 } else { 241 if (p->p_cpulimit < rlim.rlim_max) 242 p->p_cpulimit += 5; 243 mtx_unlock_spin(&sched_lock); 244 psignal(p, SIGXCPU); 245 } 246 PROC_UNLOCK(p); 247 } 248 #ifdef MAC 249 if (sflag & PS_MACPEND) 250 mac_thread_userret(td); 251 #endif 252 if (flags & TDF_NEEDRESCHED) { 253 #ifdef KTRACE 254 if (KTRPOINT(td, KTR_CSW)) 255 ktrcsw(1, 1); 256 #endif 257 mtx_lock_spin(&sched_lock); 258 sched_prio(td, kg->kg_user_pri); 259 mi_switch(SW_INVOL, NULL); 260 mtx_unlock_spin(&sched_lock); 261 #ifdef KTRACE 262 if (KTRPOINT(td, KTR_CSW)) 263 ktrcsw(0, 1); 264 #endif 265 } 266 if (flags & TDF_NEEDSIGCHK) { 267 PROC_LOCK(p); 268 mtx_lock(&p->p_sigacts->ps_mtx); 269 while ((sig = cursig(td)) != 0) 270 postsig(sig); 271 mtx_unlock(&p->p_sigacts->ps_mtx); 272 PROC_UNLOCK(p); 273 } 274 275 userret(td, framep, sticks); 276 mtx_assert(&Giant, MA_NOTOWNED); 277 }
Cache object: 69885ca3af902f660f1af7be06699d15
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