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/timer.h> 29 #include <linux/slab.h> 30 #include <linux/uaccess.h> 31 #include <linux/hardirq.h> 32 #include <linux/workqueue.h> 33 34 #include "internal.h" 35 36 /* 37 * We defer making "oops" entries appear in pstore - see 38 * whether the system is actually still running well enough 39 * to let someone see the entry 40 */ 41 #define PSTORE_INTERVAL (60 * HZ) 42 43 static int pstore_new_entry; 44 45 static void pstore_timefunc(unsigned long); 46 static DEFINE_TIMER(pstore_timer, pstore_timefunc, 0, 0); 47 48 static void pstore_dowork(struct work_struct *); 49 static DECLARE_WORK(pstore_work, pstore_dowork); 50 51 /* 52 * pstore_lock just protects "psinfo" during 53 * calls to pstore_register() 54 */ 55 static DEFINE_SPINLOCK(pstore_lock); 56 static struct pstore_info *psinfo; 57 58 static char *backend; 59 60 /* How much of the console log to snapshot */ 61 static unsigned long kmsg_bytes = 10240; 62 63 void pstore_set_kmsg_bytes(int bytes) 64 { 65 kmsg_bytes = bytes; 66 } 67 68 /* Tag each group of saved records with a sequence number */ 69 static int oopscount; 70 71 static const char *get_reason_str(enum kmsg_dump_reason reason) 72 { 73 switch (reason) { 74 case KMSG_DUMP_PANIC: 75 return "Panic"; 76 case KMSG_DUMP_OOPS: 77 return "Oops"; 78 case KMSG_DUMP_EMERG: 79 return "Emergency"; 80 case KMSG_DUMP_RESTART: 81 return "Restart"; 82 case KMSG_DUMP_HALT: 83 return "Halt"; 84 case KMSG_DUMP_POWEROFF: 85 return "Poweroff"; 86 default: 87 return "Unknown"; 88 } 89 } 90 91 /* 92 * callback from kmsg_dump. (s2,l2) has the most recently 93 * written bytes, older bytes are in (s1,l1). Save as much 94 * as we can from the end of the buffer. 95 */ 96 static void pstore_dump(struct kmsg_dumper *dumper, 97 enum kmsg_dump_reason reason, 98 const char *s1, unsigned long l1, 99 const char *s2, unsigned long l2) 100 { 101 unsigned long s1_start, s2_start; 102 unsigned long l1_cpy, l2_cpy; 103 unsigned long size, total = 0; 104 char *dst; 105 const char *why; 106 u64 id; 107 int hsize, ret; 108 unsigned int part = 1; 109 unsigned long flags = 0; 110 int is_locked = 0; 111 112 why = get_reason_str(reason); 113 114 if (in_nmi()) { 115 is_locked = spin_trylock(&psinfo->buf_lock); 116 if (!is_locked) 117 pr_err("pstore dump routine blocked in NMI, may corrupt error record\n"); 118 } else 119 spin_lock_irqsave(&psinfo->buf_lock, flags); 120 oopscount++; 121 while (total < kmsg_bytes) { 122 dst = psinfo->buf; 123 hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part); 124 size = psinfo->bufsize - hsize; 125 dst += hsize; 126 127 l2_cpy = min(l2, size); 128 l1_cpy = min(l1, size - l2_cpy); 129 130 if (l1_cpy + l2_cpy == 0) 131 break; 132 133 s2_start = l2 - l2_cpy; 134 s1_start = l1 - l1_cpy; 135 136 memcpy(dst, s1 + s1_start, l1_cpy); 137 memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy); 138 139 ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part, 140 hsize + l1_cpy + l2_cpy, psinfo); 141 if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted()) 142 pstore_new_entry = 1; 143 l1 -= l1_cpy; 144 l2 -= l2_cpy; 145 total += l1_cpy + l2_cpy; 146 part++; 147 } 148 if (in_nmi()) { 149 if (is_locked) 150 spin_unlock(&psinfo->buf_lock); 151 } else 152 spin_unlock_irqrestore(&psinfo->buf_lock, flags); 153 } 154 155 static struct kmsg_dumper pstore_dumper = { 156 .dump = pstore_dump, 157 }; 158 159 /* 160 * platform specific persistent storage driver registers with 161 * us here. If pstore is already mounted, call the platform 162 * read function right away to populate the file system. If not 163 * then the pstore mount code will call us later to fill out 164 * the file system. 165 * 166 * Register with kmsg_dump to save last part of console log on panic. 167 */ 168 int pstore_register(struct pstore_info *psi) 169 { 170 struct module *owner = psi->owner; 171 172 spin_lock(&pstore_lock); 173 if (psinfo) { 174 spin_unlock(&pstore_lock); 175 return -EBUSY; 176 } 177 178 if (backend && strcmp(backend, psi->name)) { 179 spin_unlock(&pstore_lock); 180 return -EINVAL; 181 } 182 183 psinfo = psi; 184 mutex_init(&psinfo->read_mutex); 185 spin_unlock(&pstore_lock); 186 187 if (owner && !try_module_get(owner)) { 188 psinfo = NULL; 189 return -EINVAL; 190 } 191 192 if (pstore_is_mounted()) 193 pstore_get_records(0); 194 195 kmsg_dump_register(&pstore_dumper); 196 197 pstore_timer.expires = jiffies + PSTORE_INTERVAL; 198 add_timer(&pstore_timer); 199 200 return 0; 201 } 202 EXPORT_SYMBOL_GPL(pstore_register); 203 204 /* 205 * Read all the records from the persistent store. Create 206 * files in our filesystem. Don't warn about -EEXIST errors 207 * when we are re-scanning the backing store looking to add new 208 * error records. 209 */ 210 void pstore_get_records(int quiet) 211 { 212 struct pstore_info *psi = psinfo; 213 char *buf = NULL; 214 ssize_t size; 215 u64 id; 216 enum pstore_type_id type; 217 struct timespec time; 218 int failed = 0, rc; 219 220 if (!psi) 221 return; 222 223 mutex_lock(&psi->read_mutex); 224 if (psi->open && psi->open(psi)) 225 goto out; 226 227 while ((size = psi->read(&id, &type, &time, &buf, psi)) > 0) { 228 rc = pstore_mkfile(type, psi->name, id, buf, (size_t)size, 229 time, psi); 230 kfree(buf); 231 buf = NULL; 232 if (rc && (rc != -EEXIST || !quiet)) 233 failed++; 234 } 235 if (psi->close) 236 psi->close(psi); 237 out: 238 mutex_unlock(&psi->read_mutex); 239 240 if (failed) 241 printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n", 242 failed, psi->name); 243 } 244 245 static void pstore_dowork(struct work_struct *work) 246 { 247 pstore_get_records(1); 248 } 249 250 static void pstore_timefunc(unsigned long dummy) 251 { 252 if (pstore_new_entry) { 253 pstore_new_entry = 0; 254 schedule_work(&pstore_work); 255 } 256 257 mod_timer(&pstore_timer, jiffies + PSTORE_INTERVAL); 258 } 259 260 module_param(backend, charp, 0444); 261 MODULE_PARM_DESC(backend, "Pstore backend to use"); 262