FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_trap.c
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 * $FreeBSD: releng/5.1/sys/kern/subr_trap.c 114983 2003-05-13 20:36:02Z jhb $
39 */
40
41 #include "opt_mac.h"
42 #ifdef __i386__
43 #include "opt_npx.h"
44 #endif
45
46 #include <sys/param.h>
47 #include <sys/bus.h>
48 #include <sys/kernel.h>
49 #include <sys/lock.h>
50 #include <sys/mac.h>
51 #include <sys/mutex.h>
52 #include <sys/proc.h>
53 #include <sys/kse.h>
54 #include <sys/ktr.h>
55 #include <sys/resourcevar.h>
56 #include <sys/sched.h>
57 #include <sys/signalvar.h>
58 #include <sys/systm.h>
59 #include <sys/vmmeter.h>
60 #include <machine/cpu.h>
61 #include <machine/pcb.h>
62
63 /*
64 * Define the code needed before returning to user mode, for
65 * trap and syscall.
66 *
67 * MPSAFE
68 */
69 void
70 userret(td, frame, oticks)
71 struct thread *td;
72 struct trapframe *frame;
73 u_int oticks;
74 {
75 struct proc *p = td->td_proc;
76
77 CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid,
78 p->p_comm);
79 #ifdef INVARIANTS
80 /* Check that we called signotify() enough. */
81 PROC_LOCK(p);
82 mtx_lock_spin(&sched_lock);
83 if (SIGPENDING(td) && ((td->td_flags & TDF_NEEDSIGCHK) == 0 ||
84 (td->td_flags & TDF_ASTPENDING) == 0))
85 printf("failed to set signal flags properly for ast()\n");
86 mtx_unlock_spin(&sched_lock);
87 PROC_UNLOCK(p);
88 #endif
89
90 /*
91 * Let the scheduler adjust our priority etc.
92 */
93 sched_userret(td);
94
95 /*
96 * We need to check to see if we have to exit or wait due to a
97 * single threading requirement or some other STOP condition.
98 * Don't bother doing all the work if the stop bits are not set
99 * at this time.. If we miss it, we miss it.. no big deal.
100 */
101 if (P_SHOULDSTOP(p)) {
102 PROC_LOCK(p);
103 thread_suspend_check(0); /* Can suspend or kill */
104 PROC_UNLOCK(p);
105 }
106
107 /*
108 * Do special thread processing, e.g. upcall tweaking and such.
109 */
110 if (p->p_flag & P_THREADED) {
111 thread_userret(td, frame);
112 }
113
114 /*
115 * Charge system time if profiling.
116 */
117 if (p->p_flag & P_PROFIL) {
118 quad_t ticks;
119
120 mtx_lock_spin(&sched_lock);
121 ticks = td->td_sticks - oticks;
122 mtx_unlock_spin(&sched_lock);
123 addupc_task(td, TRAPF_PC(frame), (u_int)ticks * psratio);
124 }
125 }
126
127 /*
128 * Process an asynchronous software trap.
129 * This is relatively easy.
130 * This function will return with preemption disabled.
131 */
132 void
133 ast(struct trapframe *framep)
134 {
135 struct thread *td;
136 struct proc *p;
137 struct kse *ke;
138 struct ksegrp *kg;
139 struct rlimit *rlim;
140 u_int prticks, sticks;
141 int sflag;
142 int flags;
143 int sig;
144 #if defined(DEV_NPX) && !defined(SMP)
145 int ucode;
146 #endif
147
148 td = curthread;
149 p = td->td_proc;
150 kg = td->td_ksegrp;
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 mtx_assert(&sched_lock, MA_NOTOWNED);
158 td->td_frame = framep;
159
160 /*
161 * This updates the p_sflag'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 sflag, the astpending flag will be set and
165 * ast() will be called again.
166 */
167 mtx_lock_spin(&sched_lock);
168 ke = td->td_kse;
169 sticks = td->td_sticks;
170 flags = td->td_flags;
171 sflag = p->p_sflag;
172 p->p_sflag &= ~(PS_ALRMPEND | PS_PROFPEND | PS_XCPU);
173 #ifdef MAC
174 p->p_sflag &= ~PS_MACPEND;
175 #endif
176 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK |
177 TDF_NEEDRESCHED | TDF_OWEUPC);
178 cnt.v_soft++;
179 prticks = 0;
180 if (flags & TDF_OWEUPC && p->p_flag & P_PROFIL) {
181 prticks = p->p_stats->p_prof.pr_ticks;
182 p->p_stats->p_prof.pr_ticks = 0;
183 }
184 mtx_unlock_spin(&sched_lock);
185 /*
186 * XXXKSE While the fact that we owe a user profiling
187 * tick is stored per KSE in this code, the statistics
188 * themselves are still stored per process.
189 * This should probably change, by which I mean that
190 * possibly the location of both might change.
191 */
192
193 if (td->td_ucred != p->p_ucred)
194 cred_update_thread(td);
195 if (flags & TDF_OWEUPC && p->p_flag & P_PROFIL)
196 addupc_task(td, p->p_stats->p_prof.pr_addr, prticks);
197 if (sflag & PS_ALRMPEND) {
198 PROC_LOCK(p);
199 psignal(p, SIGVTALRM);
200 PROC_UNLOCK(p);
201 }
202 #if defined(DEV_NPX) && !defined(SMP)
203 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) {
204 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags,
205 PCB_NPXTRAP);
206 ucode = npxtrap();
207 if (ucode != -1) {
208 trapsignal(td, SIGFPE, ucode);
209 }
210 }
211 #endif
212 if (sflag & PS_PROFPEND) {
213 PROC_LOCK(p);
214 psignal(p, SIGPROF);
215 PROC_UNLOCK(p);
216 }
217 if (sflag & PS_XCPU) {
218 PROC_LOCK(p);
219 rlim = &p->p_rlimit[RLIMIT_CPU];
220 mtx_lock_spin(&sched_lock);
221 if (p->p_runtime.sec >= rlim->rlim_max) {
222 mtx_unlock_spin(&sched_lock);
223 killproc(p, "exceeded maximum CPU limit");
224 } else {
225 if (p->p_cpulimit < rlim->rlim_max)
226 p->p_cpulimit += 5;
227 mtx_unlock_spin(&sched_lock);
228 psignal(p, SIGXCPU);
229 }
230 PROC_UNLOCK(p);
231 }
232 #ifdef MAC
233 if (sflag & PS_MACPEND)
234 mac_thread_userret(td);
235 #endif
236 if (flags & TDF_NEEDRESCHED) {
237 mtx_lock_spin(&sched_lock);
238 sched_prio(td, kg->kg_user_pri);
239 p->p_stats->p_ru.ru_nivcsw++;
240 mi_switch();
241 mtx_unlock_spin(&sched_lock);
242 }
243 if (flags & TDF_NEEDSIGCHK) {
244 int sigs;
245
246 sigs = 0;
247 PROC_LOCK(p);
248 mtx_lock(&p->p_sigacts->ps_mtx);
249 while ((sig = cursig(td)) != 0) {
250 postsig(sig);
251 sigs++;
252 }
253 mtx_unlock(&p->p_sigacts->ps_mtx);
254 PROC_UNLOCK(p);
255 if (p->p_flag & P_THREADED && sigs) {
256 struct kse_upcall *ku = td->td_upcall;
257 if ((void *)TRAPF_PC(framep) != ku->ku_func) {
258 mtx_lock_spin(&sched_lock);
259 ku->ku_flags |= KUF_DOUPCALL;
260 mtx_unlock_spin(&sched_lock);
261 }
262 }
263 }
264
265 userret(td, framep, sticks);
266 #ifdef DIAGNOSTIC
267 cred_free_thread(td);
268 #endif
269 mtx_assert(&Giant, MA_NOTOWNED);
270 }
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