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
7 * This code is derived from software contributed to Berkeley by
8 * the University of Utah, and William Jolitz.
10 * Portions of this software were developed by A. Joseph Koshy under
11 * sponsorship from the FreeBSD Foundation and Google, Inc.
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
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.
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
41 * from: @(#)trap.c 7.4 (Berkeley) 5/13/91
44 #include <sys/cdefs.h>
45 __FBSDID("$FreeBSD$");
47 #include "opt_ktrace.h"
48 #include "opt_kdtrace.h"
49 #include "opt_sched.h"
51 #include <sys/param.h>
53 #include <sys/kernel.h>
55 #include <sys/mutex.h>
56 #include <sys/pmckern.h>
59 #include <sys/pioctl.h>
60 #include <sys/ptrace.h>
61 #include <sys/resourcevar.h>
62 #include <sys/sched.h>
63 #include <sys/signalvar.h>
64 #include <sys/syscall.h>
65 #include <sys/sysent.h>
66 #include <sys/systm.h>
67 #include <sys/vmmeter.h>
70 #include <sys/ktrace.h>
72 #include <security/audit/audit.h>
74 #include <machine/cpu.h>
78 #include <vm/vm_param.h>
82 #include <security/mac/mac_framework.h>
85 * Define the code needed before returning to user mode, for trap and
89 userret(struct thread *td, struct trapframe *frame)
91 struct proc *p = td->td_proc;
93 CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid,
97 /* Check that we called signotify() enough. */
100 if (SIGPENDING(td) && ((td->td_flags & TDF_NEEDSIGCHK) == 0 ||
101 (td->td_flags & TDF_ASTPENDING) == 0))
102 printf("failed to set signal flags properly for ast()\n");
111 * If this thread tickled GEOM, we need to wait for the giggling to
112 * stop before we return to userland
114 if (td->td_pflags & TDP_GEOM)
118 * Charge system time if profiling.
120 if (p->p_flag & P_PROFIL)
121 addupc_task(td, TRAPF_PC(frame), td->td_pticks * psratio);
123 * Let the scheduler adjust our priority etc.
126 KASSERT(td->td_locks == 0,
127 ("userret: Returning with %d locks held.", td->td_locks));
134 * Process an asynchronous software trap.
135 * This is relatively easy.
136 * This function will return with preemption disabled.
139 ast(struct trapframe *framep)
149 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid,
151 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode"));
152 WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode");
153 mtx_assert(&Giant, MA_NOTOWNED);
154 THREAD_LOCK_ASSERT(td, MA_NOTOWNED);
155 td->td_frame = framep;
159 * This updates the td_flag's for the checks below in one
160 * "atomic" operation with turning off the astpending flag.
161 * If another AST is triggered while we are handling the
162 * AST's saved in flags, the astpending flag will be set and
163 * ast() will be called again.
166 flags = td->td_flags;
167 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | TDF_NEEDSUSPCHK |
168 TDF_NEEDRESCHED | TDF_ALRMPEND | TDF_PROFPEND | TDF_MACPEND);
170 PCPU_INC(cnt.v_trap);
172 if (td->td_ucred != p->p_ucred)
173 cred_update_thread(td);
174 if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) {
175 addupc_task(td, td->td_profil_addr, td->td_profil_ticks);
176 td->td_profil_ticks = 0;
177 td->td_pflags &= ~TDP_OWEUPC;
179 if (flags & TDF_ALRMPEND) {
181 psignal(p, SIGVTALRM);
184 if (flags & TDF_PROFPEND) {
190 if (flags & TDF_MACPEND)
191 mac_thread_userret(td);
193 if (flags & TDF_NEEDRESCHED) {
195 if (KTRPOINT(td, KTR_CSW))
199 sched_prio(td, td->td_user_pri);
200 mi_switch(SW_INVOL | SWT_NEEDRESCHED, NULL);
203 if (KTRPOINT(td, KTR_CSW))
209 * Check for signals. Unlocked reads of p_pendingcnt or
210 * p_siglist might cause process-directed signal to be handled
213 if (flags & TDF_NEEDSIGCHK || p->p_pendingcnt > 0 ||
214 !SIGISEMPTY(p->p_siglist)) {
216 mtx_lock(&p->p_sigacts->ps_mtx);
217 while ((sig = cursig(td, SIG_STOP_ALLOWED)) != 0)
219 mtx_unlock(&p->p_sigacts->ps_mtx);
223 * We need to check to see if we have to exit or wait due to a
224 * single threading requirement or some other STOP condition.
226 if (flags & TDF_NEEDSUSPCHK) {
228 thread_suspend_check(0);
232 if (td->td_pflags & TDP_OLDMASK) {
233 td->td_pflags &= ~TDP_OLDMASK;
234 kern_sigprocmask(td, SIG_SETMASK, &td->td_oldsigmask, NULL, 0);
238 mtx_assert(&Giant, MA_NOTOWNED);
241 #ifdef HAVE_SYSCALL_ARGS_DEF
243 syscallname(struct proc *p, u_int code)
245 static const char unknown[] = "unknown";
246 struct sysentvec *sv;
249 if (sv->sv_syscallnames == NULL || code >= sv->sv_size)
251 return (sv->sv_syscallnames[code]);
255 syscallenter(struct thread *td, struct syscall_args *sa)
260 PCPU_INC(cnt.v_syscall);
265 if (td->td_ucred != p->p_ucred)
266 cred_update_thread(td);
267 if (p->p_flag & P_TRACED) {
270 td->td_dbgflags &= ~TDB_USERWR;
271 td->td_dbgflags |= TDB_SCE;
275 error = (p->p_sysent->sv_fetch_syscall_args)(td, sa);
277 if (KTRPOINT(td, KTR_SYSCALL))
278 ktrsyscall(sa->code, sa->narg, sa->args);
282 "syscall: td=%p pid %d %s (%#lx, %#lx, %#lx)",
283 td, td->td_proc->p_pid, syscallname(p, sa->code),
284 sa->args[0], sa->args[1], sa->args[2]);
287 STOPEVENT(p, S_SCE, sa->narg);
288 PTRACESTOP_SC(p, td, S_PT_SCE);
289 if (td->td_dbgflags & TDB_USERWR) {
291 * Reread syscall number and arguments if
292 * debugger modified registers or memory.
294 error = (p->p_sysent->sv_fetch_syscall_args)(td, sa);
296 if (KTRPOINT(td, KTR_SYSCALL))
297 ktrsyscall(sa->code, sa->narg, sa->args);
305 * If the systrace module has registered it's probe
306 * callback and if there is a probe active for the
307 * syscall 'entry', process the probe.
309 if (systrace_probe_func != NULL && sa->callp->sy_entry != 0)
310 (*systrace_probe_func)(sa->callp->sy_entry, sa->code,
311 sa->callp, sa->args);
314 AUDIT_SYSCALL_ENTER(sa->code, td);
315 error = (sa->callp->sy_call)(td, sa->args);
316 AUDIT_SYSCALL_EXIT(error, td);
318 /* Save the latest error return value. */
319 td->td_errno = error;
323 * If the systrace module has registered it's probe
324 * callback and if there is a probe active for the
325 * syscall 'return', process the probe.
327 if (systrace_probe_func != NULL && sa->callp->sy_return != 0)
328 (*systrace_probe_func)(sa->callp->sy_return, sa->code,
329 sa->callp, sa->args);
331 CTR4(KTR_SYSC, "syscall: p=%p error=%d return %#lx %#lx",
332 p, error, td->td_retval[0], td->td_retval[1]);
337 td->td_dbgflags &= ~TDB_SCE;
340 (p->p_sysent->sv_set_syscall_retval)(td, error);
345 syscallret(struct thread *td, int error, struct syscall_args *sa __unused)
353 * Check for misbehavior.
355 WITNESS_WARN(WARN_PANIC, NULL, "System call %s returning",
356 syscallname(p, sa->code));
357 KASSERT(td->td_critnest == 0,
358 ("System call %s returning in a critical section",
359 syscallname(p, sa->code)));
360 KASSERT(td->td_locks == 0,
361 ("System call %s returning with %d locks held",
362 syscallname(p, sa->code), td->td_locks));
365 * Handle reschedule and other end-of-syscall issues
367 userret(td, td->td_frame);
369 CTR4(KTR_SYSC, "syscall %s exit thread %p pid %d proc %s",
370 syscallname(p, sa->code), td, td->td_proc->p_pid, td->td_name);
373 if (KTRPOINT(td, KTR_SYSRET))
374 ktrsysret(sa->code, error, td->td_retval[0]);
377 if (p->p_flag & P_TRACED) {
380 td->td_dbgflags |= TDB_SCX;
385 * This works because errno is findable through the
386 * register set. If we ever support an emulation where this
387 * is not the case, this code will need to be revisited.
389 STOPEVENT(p, S_SCX, sa->code);
390 PTRACESTOP_SC(p, td, S_PT_SCX);
391 if (traced || (td->td_dbgflags & TDB_EXEC) != 0) {
393 td->td_dbgflags &= ~(TDB_SCX | TDB_EXEC);
397 #endif /* HAVE_SYSCALL_ARGS_DEF */