| 1 | /* $Id: nmi.c,v 1.4 2013/11/26 20:29:40 rmind Exp $ */ |
| 2 | |
| 3 | /*- |
| 4 | * Copyright (c)2009,2011 YAMAMOTO Takashi, |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * Redistribution and use in source and binary forms, with or without |
| 8 | * modification, are permitted provided that the following conditions |
| 9 | * are met: |
| 10 | * 1. Redistributions of source code must retain the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer. |
| 12 | * 2. Redistributions in binary form must reproduce the above copyright |
| 13 | * notice, this list of conditions and the following disclaimer in the |
| 14 | * documentation and/or other materials provided with the distribution. |
| 15 | * |
| 16 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
| 17 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 18 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 19 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
| 20 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 21 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 22 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 23 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 24 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 25 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 26 | * SUCH DAMAGE. |
| 27 | */ |
| 28 | |
| 29 | #include <sys/cdefs.h> |
| 30 | __KERNEL_RCSID(0, "$NetBSD: nmi.c,v 1.4 2013/11/26 20:29:40 rmind Exp $" ); |
| 31 | |
| 32 | /* |
| 33 | * nmi dispatcher. |
| 34 | * |
| 35 | * XXX no need to be nmi-specific. |
| 36 | * actual assumptions are: |
| 37 | * - dispatch() is called with preemption disabled. |
| 38 | * - handlers never block. |
| 39 | * - establish() and disestablish() are called within a thread context. |
| 40 | * (thus can block) |
| 41 | */ |
| 42 | |
| 43 | #include <sys/param.h> |
| 44 | #include <sys/kernel.h> |
| 45 | #include <sys/systm.h> |
| 46 | #include <sys/atomic.h> |
| 47 | #include <sys/kmem.h> |
| 48 | #include <sys/mutex.h> |
| 49 | #include <sys/pserialize.h> |
| 50 | |
| 51 | #include <x86/nmi.h> |
| 52 | |
| 53 | struct nmi_handler { |
| 54 | int (*n_func)(const struct trapframe *, void *); |
| 55 | void *n_arg; |
| 56 | struct nmi_handler *n_next; |
| 57 | }; |
| 58 | |
| 59 | static kmutex_t nmi_list_lock; /* serialize establish and disestablish */ |
| 60 | static pserialize_t nmi_psz; |
| 61 | static nmi_handler_t *nmi_handlers; /* list of handlers */ |
| 62 | |
| 63 | /* |
| 64 | * nmi_establish: establish an nmi handler |
| 65 | * |
| 66 | * => can block. |
| 67 | * => returns an opaque handle. |
| 68 | */ |
| 69 | |
| 70 | nmi_handler_t * |
| 71 | nmi_establish(int (*func)(const struct trapframe *, void *), void *arg) |
| 72 | { |
| 73 | struct nmi_handler *n; |
| 74 | |
| 75 | n = kmem_alloc(sizeof(*n), KM_SLEEP); |
| 76 | if (n == NULL) { |
| 77 | return NULL; |
| 78 | } |
| 79 | n->n_func = func; |
| 80 | n->n_arg = arg; |
| 81 | |
| 82 | /* |
| 83 | * put it into the list. |
| 84 | */ |
| 85 | |
| 86 | mutex_enter(&nmi_list_lock); |
| 87 | n->n_next = nmi_handlers; |
| 88 | membar_producer(); /* n->n_next should be visible before nmi_handlers */ |
| 89 | nmi_handlers = n; /* atomic store */ |
| 90 | mutex_exit(&nmi_list_lock); |
| 91 | |
| 92 | return n; |
| 93 | } |
| 94 | |
| 95 | /* |
| 96 | * nmi_disestablish: disestablish an nmi handler. |
| 97 | * |
| 98 | * => can block. |
| 99 | * => take an opaque handle. it must be one returned by nmi_establish. |
| 100 | */ |
| 101 | |
| 102 | void |
| 103 | nmi_disestablish(nmi_handler_t *handle) |
| 104 | { |
| 105 | nmi_handler_t *n; |
| 106 | nmi_handler_t **pp; |
| 107 | |
| 108 | KASSERT(handle != NULL); |
| 109 | |
| 110 | /* |
| 111 | * remove the handler from the list. |
| 112 | */ |
| 113 | |
| 114 | mutex_enter(&nmi_list_lock); |
| 115 | for (pp = &nmi_handlers, n = *pp; n != NULL; n = *pp) { |
| 116 | if (n == handle) { |
| 117 | break; |
| 118 | } |
| 119 | pp = &n->n_next; |
| 120 | } |
| 121 | #if defined(DIAGNOSTIC) |
| 122 | if (n == NULL) { |
| 123 | mutex_exit(&nmi_list_lock); |
| 124 | panic("%s: invalid handle %p" , __func__, handle); |
| 125 | } |
| 126 | #endif /* defined(DIAGNOSTIC) */ |
| 127 | *pp = n->n_next; /* atomic store */ |
| 128 | mutex_exit(&nmi_list_lock); /* mutex_exit implies a store fence */ |
| 129 | |
| 130 | /* |
| 131 | * before freeing 'n', ensure that no other cpus are |
| 132 | * in the middle of nmi_dispatch. |
| 133 | */ |
| 134 | |
| 135 | pserialize_perform(nmi_psz); |
| 136 | kmem_free(n, sizeof(*n)); |
| 137 | } |
| 138 | |
| 139 | /* |
| 140 | * nmi_dispatch: dispatch an nmi. |
| 141 | * |
| 142 | * => called by interrupts, thus preempt disabled. |
| 143 | */ |
| 144 | |
| 145 | int |
| 146 | nmi_dispatch(const struct trapframe *tf) |
| 147 | { |
| 148 | const struct nmi_handler *n; |
| 149 | int handled = 0; |
| 150 | |
| 151 | /* |
| 152 | * XXX abstraction violation |
| 153 | * |
| 154 | * we don't bother to call pserialize_read_enter/pserialize_read_exit |
| 155 | * because they are not necessary here as we are sure our IPL is |
| 156 | * higher than IPL_SOFTSERIAL. better to avoid unnecessary calls as |
| 157 | * we are in a dangerous context. (NMI) |
| 158 | */ |
| 159 | |
| 160 | for (n = nmi_handlers; /* atomic load */ |
| 161 | n != NULL; |
| 162 | membar_consumer(), n = n->n_next) { /* atomic load */ |
| 163 | handled |= (*n->n_func)(tf, n->n_arg); |
| 164 | } |
| 165 | return handled; |
| 166 | } |
| 167 | |
| 168 | void |
| 169 | nmi_init(void) |
| 170 | { |
| 171 | |
| 172 | mutex_init(&nmi_list_lock, MUTEX_DEFAULT, IPL_NONE); |
| 173 | nmi_psz = pserialize_create(); |
| 174 | } |
| 175 | |