Tony Luck | ca01d6d | 2010-12-28 14:25:21 -0800 | [diff] [blame^] | 1 | /* |
| 2 | * Persistent Storage - platform driver interface parts. |
| 3 | * |
| 4 | * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License version 2 as |
| 8 | * published by the Free Software Foundation. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License |
| 16 | * along with this program; if not, write to the Free Software |
| 17 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 18 | */ |
| 19 | |
| 20 | #include <linux/atomic.h> |
| 21 | #include <linux/types.h> |
| 22 | #include <linux/errno.h> |
| 23 | #include <linux/init.h> |
| 24 | #include <linux/kmsg_dump.h> |
| 25 | #include <linux/module.h> |
| 26 | #include <linux/pstore.h> |
| 27 | #include <linux/string.h> |
| 28 | #include <linux/slab.h> |
| 29 | #include <linux/uaccess.h> |
| 30 | |
| 31 | #include "internal.h" |
| 32 | |
| 33 | /* |
| 34 | * pstore_lock just protects "psinfo" during |
| 35 | * calls to pstore_register() |
| 36 | */ |
| 37 | static DEFINE_SPINLOCK(pstore_lock); |
| 38 | static struct pstore_info *psinfo; |
| 39 | |
| 40 | /* How much of the console log to snapshot. /sys/fs/pstore/kmsg_bytes */ |
| 41 | static unsigned long kmsg_bytes = 10240; |
| 42 | |
| 43 | static ssize_t b_show(struct kobject *kobj, |
| 44 | struct kobj_attribute *attr, char *buf) |
| 45 | { |
| 46 | return snprintf(buf, PAGE_SIZE, "%lu\n", kmsg_bytes); |
| 47 | } |
| 48 | |
| 49 | static ssize_t b_store(struct kobject *kobj, struct kobj_attribute *attr, |
| 50 | const char *buf, size_t count) |
| 51 | { |
| 52 | return (sscanf(buf, "%lu", &kmsg_bytes) > 0) ? count : 0; |
| 53 | } |
| 54 | |
| 55 | struct kobj_attribute pstore_kmsg_bytes_attr = |
| 56 | __ATTR(kmsg_bytes, S_IRUGO | S_IWUSR, b_show, b_store); |
| 57 | |
| 58 | /* Tag each group of saved records with a sequence number */ |
| 59 | static int oopscount; |
| 60 | |
| 61 | /* |
| 62 | * callback from kmsg_dump. (s2,l2) has the most recently |
| 63 | * written bytes, older bytes are in (s1,l1). Save as much |
| 64 | * as we can from the end of the buffer. |
| 65 | */ |
| 66 | static void pstore_dump(struct kmsg_dumper *dumper, |
| 67 | enum kmsg_dump_reason reason, |
| 68 | const char *s1, unsigned long l1, |
| 69 | const char *s2, unsigned long l2) |
| 70 | { |
| 71 | unsigned long s1_start, s2_start; |
| 72 | unsigned long l1_cpy, l2_cpy; |
| 73 | unsigned long size, total = 0; |
| 74 | char *dst; |
| 75 | u64 id; |
| 76 | int hsize, part = 1; |
| 77 | |
| 78 | mutex_lock(&psinfo->buf_mutex); |
| 79 | oopscount++; |
| 80 | while (total < kmsg_bytes) { |
| 81 | dst = psinfo->buf; |
| 82 | hsize = sprintf(dst, "Oops#%d Part%d\n", oopscount, part++); |
| 83 | size = psinfo->bufsize - hsize; |
| 84 | dst += hsize; |
| 85 | |
| 86 | l2_cpy = min(l2, size); |
| 87 | l1_cpy = min(l1, size - l2_cpy); |
| 88 | |
| 89 | if (l1_cpy + l2_cpy == 0) |
| 90 | break; |
| 91 | |
| 92 | s2_start = l2 - l2_cpy; |
| 93 | s1_start = l1 - l1_cpy; |
| 94 | |
| 95 | memcpy(dst, s1 + s1_start, l1_cpy); |
| 96 | memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy); |
| 97 | |
| 98 | id = psinfo->write(PSTORE_TYPE_DMESG, hsize + l1_cpy + l2_cpy); |
| 99 | if (pstore_is_mounted()) |
| 100 | pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id, |
| 101 | psinfo->buf, hsize + l1_cpy + l2_cpy, |
| 102 | CURRENT_TIME, psinfo->erase); |
| 103 | l1 -= l1_cpy; |
| 104 | l2 -= l2_cpy; |
| 105 | total += l1_cpy + l2_cpy; |
| 106 | } |
| 107 | mutex_unlock(&psinfo->buf_mutex); |
| 108 | } |
| 109 | |
| 110 | static struct kmsg_dumper pstore_dumper = { |
| 111 | .dump = pstore_dump, |
| 112 | }; |
| 113 | |
| 114 | /* |
| 115 | * platform specific persistent storage driver registers with |
| 116 | * us here. If pstore is already mounted, call the platform |
| 117 | * read function right away to populate the file system. If not |
| 118 | * then the pstore mount code will call us later to fill out |
| 119 | * the file system. |
| 120 | * |
| 121 | * Register with kmsg_dump to save last part of console log on panic. |
| 122 | */ |
| 123 | int pstore_register(struct pstore_info *psi) |
| 124 | { |
| 125 | struct module *owner = psi->owner; |
| 126 | |
| 127 | spin_lock(&pstore_lock); |
| 128 | if (psinfo) { |
| 129 | spin_unlock(&pstore_lock); |
| 130 | return -EBUSY; |
| 131 | } |
| 132 | psinfo = psi; |
| 133 | spin_unlock(&pstore_lock); |
| 134 | |
| 135 | if (owner && !try_module_get(owner)) { |
| 136 | psinfo = NULL; |
| 137 | return -EINVAL; |
| 138 | } |
| 139 | |
| 140 | if (pstore_is_mounted()) |
| 141 | pstore_get_records(); |
| 142 | |
| 143 | kmsg_dump_register(&pstore_dumper); |
| 144 | |
| 145 | return 0; |
| 146 | } |
| 147 | EXPORT_SYMBOL_GPL(pstore_register); |
| 148 | |
| 149 | /* |
| 150 | * Read all the records from the persistent store. Create and |
| 151 | * file files in our filesystem. |
| 152 | */ |
| 153 | void pstore_get_records(void) |
| 154 | { |
| 155 | struct pstore_info *psi = psinfo; |
| 156 | size_t size; |
| 157 | u64 id; |
| 158 | enum pstore_type_id type; |
| 159 | struct timespec time; |
| 160 | int failed = 0; |
| 161 | |
| 162 | if (!psi) |
| 163 | return; |
| 164 | |
| 165 | mutex_lock(&psinfo->buf_mutex); |
| 166 | while ((size = psi->read(&id, &type, &time)) > 0) { |
| 167 | if (pstore_mkfile(type, psi->name, id, psi->buf, size, |
| 168 | time, psi->erase)) |
| 169 | failed++; |
| 170 | } |
| 171 | mutex_unlock(&psinfo->buf_mutex); |
| 172 | |
| 173 | if (failed) |
| 174 | printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n", |
| 175 | failed, psi->name); |
| 176 | } |
| 177 | |
| 178 | /* |
| 179 | * Call platform driver to write a record to the |
| 180 | * persistent store. |
| 181 | */ |
| 182 | int pstore_write(enum pstore_type_id type, char *buf, size_t size) |
| 183 | { |
| 184 | u64 id; |
| 185 | |
| 186 | if (!psinfo) |
| 187 | return -ENODEV; |
| 188 | |
| 189 | if (size > psinfo->bufsize) |
| 190 | return -EFBIG; |
| 191 | |
| 192 | mutex_lock(&psinfo->buf_mutex); |
| 193 | memcpy(psinfo->buf, buf, size); |
| 194 | id = psinfo->write(type, size); |
| 195 | if (pstore_is_mounted()) |
| 196 | pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id, psinfo->buf, |
| 197 | size, CURRENT_TIME, psinfo->erase); |
| 198 | mutex_unlock(&psinfo->buf_mutex); |
| 199 | |
| 200 | return 0; |
| 201 | } |
| 202 | EXPORT_SYMBOL_GPL(pstore_write); |