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 static char *backend; 41 42 /* How much of the console log to snapshot */ 43 static unsigned long kmsg_bytes = 10240; 44 45 void pstore_set_kmsg_bytes(int bytes) 46 { 47 kmsg_bytes = bytes; 48 } 49 50 /* Tag each group of saved records with a sequence number */ 51 static int oopscount; 52 53 static char *reason_str[] = { 54 "Oops", "Panic", "Kexec", "Restart", "Halt", "Poweroff", "Emergency" 55 }; 56 57 /* 58 * callback from kmsg_dump. (s2,l2) has the most recently 59 * written bytes, older bytes are in (s1,l1). Save as much 60 * as we can from the end of the buffer. 61 */ 62 static void pstore_dump(struct kmsg_dumper *dumper, 63 enum kmsg_dump_reason reason, 64 const char *s1, unsigned long l1, 65 const char *s2, unsigned long l2) 66 { 67 unsigned long s1_start, s2_start; 68 unsigned long l1_cpy, l2_cpy; 69 unsigned long size, total = 0; 70 char *dst, *why; 71 u64 id; 72 int hsize; 73 unsigned int part = 1; 74 75 if (reason < ARRAY_SIZE(reason_str)) 76 why = reason_str[reason]; 77 else 78 why = "Unknown"; 79 80 mutex_lock(&psinfo->buf_mutex); 81 oopscount++; 82 while (total < kmsg_bytes) { 83 dst = psinfo->buf; 84 hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part); 85 size = psinfo->bufsize - hsize; 86 dst += hsize; 87 88 l2_cpy = min(l2, size); 89 l1_cpy = min(l1, size - l2_cpy); 90 91 if (l1_cpy + l2_cpy == 0) 92 break; 93 94 s2_start = l2 - l2_cpy; 95 s1_start = l1 - l1_cpy; 96 97 memcpy(dst, s1 + s1_start, l1_cpy); 98 memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy); 99 100 id = psinfo->write(PSTORE_TYPE_DMESG, part, 101 hsize + l1_cpy + l2_cpy, psinfo); 102 if (reason == KMSG_DUMP_OOPS && pstore_is_mounted()) 103 pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id, 104 psinfo->buf, hsize + l1_cpy + l2_cpy, 105 CURRENT_TIME, psinfo); 106 l1 -= l1_cpy; 107 l2 -= l2_cpy; 108 total += l1_cpy + l2_cpy; 109 part++; 110 } 111 mutex_unlock(&psinfo->buf_mutex); 112 } 113 114 static struct kmsg_dumper pstore_dumper = { 115 .dump = pstore_dump, 116 }; 117 118 /* 119 * platform specific persistent storage driver registers with 120 * us here. If pstore is already mounted, call the platform 121 * read function right away to populate the file system. If not 122 * then the pstore mount code will call us later to fill out 123 * the file system. 124 * 125 * Register with kmsg_dump to save last part of console log on panic. 126 */ 127 int pstore_register(struct pstore_info *psi) 128 { 129 struct module *owner = psi->owner; 130 131 spin_lock(&pstore_lock); 132 if (psinfo) { 133 spin_unlock(&pstore_lock); 134 return -EBUSY; 135 } 136 137 if (backend && strcmp(backend, psi->name)) { 138 spin_unlock(&pstore_lock); 139 return -EINVAL; 140 } 141 142 psinfo = psi; 143 spin_unlock(&pstore_lock); 144 145 if (owner && !try_module_get(owner)) { 146 psinfo = NULL; 147 return -EINVAL; 148 } 149 150 if (pstore_is_mounted()) 151 pstore_get_records(); 152 153 kmsg_dump_register(&pstore_dumper); 154 155 return 0; 156 } 157 EXPORT_SYMBOL_GPL(pstore_register); 158 159 /* 160 * Read all the records from the persistent store. Create and 161 * file files in our filesystem. 162 */ 163 void pstore_get_records(void) 164 { 165 struct pstore_info *psi = psinfo; 166 ssize_t size; 167 u64 id; 168 enum pstore_type_id type; 169 struct timespec time; 170 int failed = 0, rc; 171 172 if (!psi) 173 return; 174 175 mutex_lock(&psinfo->buf_mutex); 176 rc = psi->open(psi); 177 if (rc) 178 goto out; 179 180 while ((size = psi->read(&id, &type, &time, psi)) > 0) { 181 if (pstore_mkfile(type, psi->name, id, psi->buf, (size_t)size, 182 time, psi)) 183 failed++; 184 } 185 psi->close(psi); 186 out: 187 mutex_unlock(&psinfo->buf_mutex); 188 189 if (failed) 190 printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n", 191 failed, psi->name); 192 } 193 194 /* 195 * Call platform driver to write a record to the 196 * persistent store. 197 */ 198 int pstore_write(enum pstore_type_id type, char *buf, size_t size) 199 { 200 u64 id; 201 202 if (!psinfo) 203 return -ENODEV; 204 205 if (size > psinfo->bufsize) 206 return -EFBIG; 207 208 mutex_lock(&psinfo->buf_mutex); 209 memcpy(psinfo->buf, buf, size); 210 id = psinfo->write(type, 0, size, psinfo); 211 if (pstore_is_mounted()) 212 pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id, psinfo->buf, 213 size, CURRENT_TIME, psinfo); 214 mutex_unlock(&psinfo->buf_mutex); 215 216 return 0; 217 } 218 EXPORT_SYMBOL_GPL(pstore_write); 219 220 module_param(backend, charp, 0444); 221 MODULE_PARM_DESC(backend, "Pstore backend to use"); 222