Make most AST handlers dynamically registered. This allows to have subsystem-specific handler source located in the subsystem files, instead of making subr_trap.c aware of it. For instance, signal delivery code on return to userspace is now moved to kern_sig.c. Also, it allows to have some handlers designated as the cleanup (kclear) type, which are called both at AST and on thread/process exit. For instance, ast(), exit1(), and NFS server no longer need to be aware about UFS softdep processing. The dynamic registration also allows third-party modules to register AST handlers if needed. There is one caveat with loadable modules: the code does not make any effort to ensure that the module is not unloaded before all threads processed through AST handler in it. In fact, this is already present behavior for hwpmc.ko and ufs.ko. I do not think it is worth the efforts and the runtime overhead to try to fix it. Reviewed by: markj Tested by: emaste (arm64), pho Discussed with: jhb Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D35888
192 lines
5.1 KiB
C
192 lines
5.1 KiB
C
/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (c) 1982, 1986, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)subr_prof.c 8.3 (Berkeley) 9/23/93
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/sysproto.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/resourcevar.h>
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#include <sys/sysctl.h>
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#include <machine/cpu.h>
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/*
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* Profiling system call.
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*
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* The scale factor is a fixed point number with 16 bits of fraction, so that
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* 1.0 is represented as 0x10000. A scale factor of 0 turns off profiling.
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*/
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#ifndef _SYS_SYSPROTO_H_
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struct profil_args {
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caddr_t samples;
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size_t size;
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size_t offset;
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u_int scale;
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};
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#endif
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/* ARGSUSED */
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int
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sys_profil(struct thread *td, struct profil_args *uap)
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{
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struct uprof *upp;
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struct proc *p;
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if (uap->scale > (1 << 16))
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return (EINVAL);
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p = td->td_proc;
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if (uap->scale == 0) {
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PROC_LOCK(p);
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stopprofclock(p);
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PROC_UNLOCK(p);
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return (0);
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}
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PROC_LOCK(p);
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upp = &td->td_proc->p_stats->p_prof;
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PROC_PROFLOCK(p);
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upp->pr_off = uap->offset;
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upp->pr_scale = uap->scale;
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upp->pr_base = uap->samples;
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upp->pr_size = uap->size;
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PROC_PROFUNLOCK(p);
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startprofclock(p);
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PROC_UNLOCK(p);
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return (0);
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}
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/*
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* Scale is a fixed-point number with the binary point 16 bits
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* into the value, and is <= 1.0. pc is at most 32 bits, so the
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* intermediate result is at most 48 bits.
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*/
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#define PC_TO_INDEX(pc, prof) \
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((int)(((u_quad_t)((pc) - (prof)->pr_off) * \
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(u_quad_t)((prof)->pr_scale)) >> 16) & ~1)
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/*
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* Collect user-level profiling statistics; called on a profiling tick,
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* when a process is running in user-mode. This routine may be called
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* from an interrupt context. We perform the update with an AST
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* that will vector us to trap() with a context in which copyin and
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* copyout will work. Trap will then call addupc_task().
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*
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* Note that we may (rarely) not get around to the AST soon enough, and
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* lose profile ticks when the next tick overwrites this one, but in this
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* case the system is overloaded and the profile is probably already
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* inaccurate.
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*/
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void
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addupc_intr(struct thread *td, uintfptr_t pc, u_int ticks)
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{
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struct uprof *prof;
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if (ticks == 0)
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return;
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prof = &td->td_proc->p_stats->p_prof;
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PROC_PROFLOCK(td->td_proc);
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if (pc < prof->pr_off || PC_TO_INDEX(pc, prof) >= prof->pr_size) {
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PROC_PROFUNLOCK(td->td_proc);
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return; /* out of range; ignore */
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}
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PROC_PROFUNLOCK(td->td_proc);
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td->td_profil_addr = pc;
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td->td_profil_ticks = ticks;
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td->td_pflags |= TDP_OWEUPC;
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ast_sched(td, TDA_OWEUPC);
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}
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/*
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* Actually update the profiling statistics. If the update fails, we
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* simply turn off profiling.
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*/
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void
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addupc_task(struct thread *td, uintfptr_t pc, u_int ticks)
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{
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struct proc *p = td->td_proc;
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struct uprof *prof;
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caddr_t addr;
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u_int i;
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u_short v;
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int stop = 0;
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if (ticks == 0)
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return;
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PROC_LOCK(p);
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if (!(p->p_flag & P_PROFIL)) {
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PROC_UNLOCK(p);
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return;
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}
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p->p_profthreads++;
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prof = &p->p_stats->p_prof;
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PROC_PROFLOCK(p);
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if (pc < prof->pr_off ||
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(i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) {
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PROC_PROFUNLOCK(p);
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goto out;
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}
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addr = prof->pr_base + i;
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PROC_PROFUNLOCK(p);
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PROC_UNLOCK(p);
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if (copyin(addr, &v, sizeof(v)) == 0) {
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v += ticks;
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if (copyout(&v, addr, sizeof(v)) == 0) {
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PROC_LOCK(p);
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goto out;
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}
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}
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stop = 1;
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PROC_LOCK(p);
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out:
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if (--p->p_profthreads == 0) {
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if (p->p_flag & P_STOPPROF) {
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wakeup(&p->p_profthreads);
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p->p_flag &= ~P_STOPPROF;
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stop = 0;
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}
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}
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if (stop)
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stopprofclock(p);
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PROC_UNLOCK(p);
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}
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