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 */
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 #include "opt_sched.h"
49
50 #include <sys/param.h>
51 #include <sys/bus.h>
52 #include <sys/kernel.h>
53 #include <sys/lock.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 #include <security/mac/mac_framework.h>
71
72 /*
73 * Define the code needed before returning to user mode, for trap and
74 * syscall.
75 */
76 void
77 userret(struct thread *td, struct trapframe *frame)
78 {
79 struct proc *p = td->td_proc;
80
81 CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid,
82 p->p_comm);
83 #ifdef DIAGNOSTIC
84 /* Check that we called signotify() enough. */
85 PROC_LOCK(p);
86 thread_lock(td);
87 if (SIGPENDING(td) && ((td->td_flags & TDF_NEEDSIGCHK) == 0 ||
88 (td->td_flags & TDF_ASTPENDING) == 0))
89 printf("failed to set signal flags properly for ast()\n");
90 thread_unlock(td);
91 PROC_UNLOCK(p);
92 #endif
93
94 #ifdef KTRACE
95 KTRUSERRET(td);
96 #endif
97
98 /*
99 * If this thread tickled GEOM, we need to wait for the giggling to
100 * stop before we return to userland
101 */
102 if (td->td_pflags & TDP_GEOM)
103 g_waitidle();
104
105 /*
106 * We need to check to see if we have to exit or wait due to a
107 * single threading requirement or some other STOP condition.
108 * Don't bother doing all the work if the stop bits are not set
109 * at this time.. If we miss it, we miss it.. no big deal.
110 */
111 if (P_SHOULDSTOP(p)) {
112 PROC_LOCK(p);
113 thread_suspend_check(0); /* Can suspend or kill */
114 PROC_UNLOCK(p);
115 }
116
117 #ifdef KSE
118 /*
119 * Do special thread processing, e.g. upcall tweaking and such.
120 */
121 if (p->p_flag & P_SA)
122 thread_userret(td, frame);
123 #endif
124
125 /*
126 * Charge system time if profiling.
127 */
128 if (p->p_flag & P_PROFIL) {
129
130 addupc_task(td, TRAPF_PC(frame), td->td_pticks * psratio);
131 }
132
133 /*
134 * Let the scheduler adjust our priority etc.
135 */
136 sched_userret(td);
137 KASSERT(td->td_locks == 0,
138 ("userret: Returning with %d locks held.", td->td_locks));
139 }
140
141 /*
142 * Process an asynchronous software trap.
143 * This is relatively easy.
144 * This function will return with preemption disabled.
145 */
146 void
147 ast(struct trapframe *framep)
148 {
149 struct thread *td;
150 struct proc *p;
151 int flags;
152 int sig;
153 #if defined(DEV_NPX) && !defined(SMP)
154 int ucode;
155 ksiginfo_t ksi;
156 #endif
157
158 td = curthread;
159 p = td->td_proc;
160
161 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid,
162 p->p_comm);
163 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode"));
164 WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode");
165 mtx_assert(&Giant, MA_NOTOWNED);
166 THREAD_LOCK_ASSERT(td, MA_NOTOWNED);
167 td->td_frame = framep;
168 td->td_pticks = 0;
169
170 #ifdef KSE
171 if ((p->p_flag & P_SA) && (td->td_mailbox == NULL))
172 thread_user_enter(td);
173 #endif
174
175 /*
176 * This updates the td_flag's for the checks below in one
177 * "atomic" operation with turning off the astpending flag.
178 * If another AST is triggered while we are handling the
179 * AST's saved in flags, the astpending flag will be set and
180 * ast() will be called again.
181 */
182 thread_lock(td);
183 flags = td->td_flags;
184 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK |
185 TDF_NEEDRESCHED | TDF_INTERRUPT | TDF_ALRMPEND | TDF_PROFPEND |
186 TDF_MACPEND);
187 thread_unlock(td);
188 PCPU_INC(cnt.v_trap);
189
190 /*
191 * XXXKSE While the fact that we owe a user profiling
192 * tick is stored per thread in this code, the statistics
193 * themselves are still stored per process.
194 * This should probably change, by which I mean that
195 * possibly the location of both might change.
196 */
197 if (td->td_ucred != p->p_ucred)
198 cred_update_thread(td);
199 if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) {
200 addupc_task(td, td->td_profil_addr, td->td_profil_ticks);
201 td->td_profil_ticks = 0;
202 td->td_pflags &= ~TDP_OWEUPC;
203 }
204 if (flags & TDF_ALRMPEND) {
205 PROC_LOCK(p);
206 psignal(p, SIGVTALRM);
207 PROC_UNLOCK(p);
208 }
209 #if defined(DEV_NPX) && !defined(SMP)
210 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) {
211 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags,
212 PCB_NPXTRAP);
213 ucode = npxtrap();
214 if (ucode != -1) {
215 ksiginfo_init_trap(&ksi);
216 ksi.ksi_signo = SIGFPE;
217 ksi.ksi_code = ucode;
218 trapsignal(td, &ksi);
219 }
220 }
221 #endif
222 if (flags & TDF_PROFPEND) {
223 PROC_LOCK(p);
224 psignal(p, SIGPROF);
225 PROC_UNLOCK(p);
226 }
227 #ifdef MAC
228 if (flags & TDF_MACPEND)
229 mac_thread_userret(td);
230 #endif
231 if (flags & TDF_NEEDRESCHED) {
232 #ifdef KTRACE
233 if (KTRPOINT(td, KTR_CSW))
234 ktrcsw(1, 1);
235 #endif
236 thread_lock(td);
237 sched_prio(td, td->td_user_pri);
238 SCHED_STAT_INC(switch_needresched);
239 mi_switch(SW_INVOL, NULL);
240 thread_unlock(td);
241 #ifdef KTRACE
242 if (KTRPOINT(td, KTR_CSW))
243 ktrcsw(0, 1);
244 #endif
245 }
246 if (flags & TDF_NEEDSIGCHK) {
247 PROC_LOCK(p);
248 mtx_lock(&p->p_sigacts->ps_mtx);
249 while ((sig = cursig(td)) != 0)
250 postsig(sig);
251 mtx_unlock(&p->p_sigacts->ps_mtx);
252 PROC_UNLOCK(p);
253 }
254
255 userret(td, framep);
256 mtx_assert(&Giant, MA_NOTOWNED);
257 }
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