5ef8fb65f9
Interrupt driven configuration hooks serve two purposes: they are a mechanism for registering for a callback that is invoked once interrupt services are available, and they hold off root device selection so long as any configuration hooks are still active. Before this change, it was not possible to safely register additional hooks from the context of a configuration hook callback. The need for this feature arises when interrupts are required to discover new devices (e.g. access to the XenStore to find para-virtualized devices) which in turn also require the ability to hold off root device selection until some lengthy, interrupt driven, configuration task has completed (e.g. Xen front/back device driver negotiation). More specifically, the mutex protecting the list of active configuration hooks is never held during a callback, and static information is used to ensure proper ordering and only a single callback to each hook even when faced with registration or removal of a hook during an active run. Sponsored by: Spectra Logic Corporation MFC after: 1 week.
231 lines
6.7 KiB
C
231 lines
6.7 KiB
C
/*-
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* Copyright (c) 1992, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This software was developed by the Computer Systems Engineering group
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* at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
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* contributed to Berkeley.
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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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* 4. 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_autoconf.c 8.1 (Berkeley) 6/10/93
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*
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_ddb.h"
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/linker.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/systm.h>
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/*
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* Autoconfiguration subroutines.
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*/
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/*
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* "Interrupt driven config" functions.
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*/
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static TAILQ_HEAD(, intr_config_hook) intr_config_hook_list =
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TAILQ_HEAD_INITIALIZER(intr_config_hook_list);
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static struct intr_config_hook *next_to_notify;
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static struct mtx intr_config_hook_lock;
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MTX_SYSINIT(intr_config_hook, &intr_config_hook_lock, "intr config", MTX_DEF);
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/* ARGSUSED */
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static void run_interrupt_driven_config_hooks(void);
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/*
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* If we wait too long for an interrupt-driven config hook to return, print
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* a diagnostic.
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*/
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#define WARNING_INTERVAL_SECS 60
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static void
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run_interrupt_driven_config_hooks_warning(int warned)
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{
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struct intr_config_hook *hook_entry;
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char namebuf[64];
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long offset;
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if (warned < 6) {
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printf("run_interrupt_driven_hooks: still waiting after %d "
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"seconds for", warned * WARNING_INTERVAL_SECS);
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TAILQ_FOREACH(hook_entry, &intr_config_hook_list, ich_links) {
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if (linker_search_symbol_name(
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(caddr_t)hook_entry->ich_func, namebuf,
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sizeof(namebuf), &offset) == 0)
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printf(" %s", namebuf);
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else
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printf(" %p", hook_entry->ich_func);
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}
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printf("\n");
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}
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KASSERT(warned < 6,
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("run_interrupt_driven_config_hooks: waited too long"));
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}
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static void
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run_interrupt_driven_config_hooks()
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{
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static int running;
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struct intr_config_hook *hook_entry;
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mtx_lock(&intr_config_hook_lock);
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/*
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* If hook processing is already active, any newly
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* registered hooks will eventually be notified.
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* Let the currently running session issue these
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* notifications.
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*/
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if (running != 0) {
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mtx_unlock(&intr_config_hook_lock);
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return;
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}
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running = 1;
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while (next_to_notify != NULL) {
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hook_entry = next_to_notify;
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next_to_notify = TAILQ_NEXT(hook_entry, ich_links);
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mtx_unlock(&intr_config_hook_lock);
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(*hook_entry->ich_func)(hook_entry->ich_arg);
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mtx_lock(&intr_config_hook_lock);
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}
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running = 0;
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mtx_unlock(&intr_config_hook_lock);
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}
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static void
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boot_run_interrupt_driven_config_hooks(void *dummy)
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{
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int warned;
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run_interrupt_driven_config_hooks();
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/* Block boot processing until all hooks are disestablished. */
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mtx_lock(&intr_config_hook_lock);
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warned = 0;
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while (!TAILQ_EMPTY(&intr_config_hook_list)) {
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if (msleep(&intr_config_hook_list, &intr_config_hook_lock,
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PCONFIG, "conifhk", WARNING_INTERVAL_SECS * hz) ==
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EWOULDBLOCK) {
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mtx_unlock(&intr_config_hook_lock);
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warned++;
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run_interrupt_driven_config_hooks_warning(warned);
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mtx_lock(&intr_config_hook_lock);
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}
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}
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mtx_unlock(&intr_config_hook_lock);
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}
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SYSINIT(intr_config_hooks, SI_SUB_INT_CONFIG_HOOKS, SI_ORDER_FIRST,
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boot_run_interrupt_driven_config_hooks, NULL);
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/*
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* Register a hook that will be called after "cold"
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* autoconfiguration is complete and interrupts can
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* be used to complete initialization.
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*/
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int
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config_intrhook_establish(struct intr_config_hook *hook)
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{
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struct intr_config_hook *hook_entry;
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mtx_lock(&intr_config_hook_lock);
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TAILQ_FOREACH(hook_entry, &intr_config_hook_list, ich_links)
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if (hook_entry == hook)
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break;
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if (hook_entry != NULL) {
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mtx_unlock(&intr_config_hook_lock);
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printf("config_intrhook_establish: establishing an "
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"already established hook.\n");
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return (1);
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}
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TAILQ_INSERT_TAIL(&intr_config_hook_list, hook, ich_links);
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if (next_to_notify == NULL)
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next_to_notify = hook;
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mtx_unlock(&intr_config_hook_lock);
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if (cold == 0)
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/*
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* XXX Call from a task since not all drivers expect
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* to be re-entered at the time a hook is established.
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*/
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/* XXX Sufficient for modules loaded after initial config??? */
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run_interrupt_driven_config_hooks();
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return (0);
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}
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void
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config_intrhook_disestablish(struct intr_config_hook *hook)
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{
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struct intr_config_hook *hook_entry;
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mtx_lock(&intr_config_hook_lock);
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TAILQ_FOREACH(hook_entry, &intr_config_hook_list, ich_links)
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if (hook_entry == hook)
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break;
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if (hook_entry == NULL)
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panic("config_intrhook_disestablish: disestablishing an "
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"unestablished hook");
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if (next_to_notify == hook)
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next_to_notify = TAILQ_NEXT(hook, ich_links);
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TAILQ_REMOVE(&intr_config_hook_list, hook, ich_links);
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/* Wakeup anyone watching the list */
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wakeup(&intr_config_hook_list);
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mtx_unlock(&intr_config_hook_lock);
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}
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#ifdef DDB
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#include <ddb/ddb.h>
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DB_SHOW_COMMAND(conifhk, db_show_conifhk)
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{
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struct intr_config_hook *hook_entry;
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char namebuf[64];
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long offset;
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TAILQ_FOREACH(hook_entry, &intr_config_hook_list, ich_links) {
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if (linker_ddb_search_symbol_name(
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(caddr_t)hook_entry->ich_func, namebuf, sizeof(namebuf),
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&offset) == 0) {
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db_printf("hook: %p at %s+%#lx arg: %p\n",
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hook_entry->ich_func, namebuf, offset,
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hook_entry->ich_arg);
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} else {
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db_printf("hook: %p at ??+?? arg %p\n",
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hook_entry->ich_func, hook_entry->ich_arg);
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}
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}
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}
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#endif /* DDB */
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