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