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ca01d6dd TL |
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 | ||
366f7e7a | 40 | /* How much of the console log to snapshot */ |
ca01d6dd TL |
41 | static unsigned long kmsg_bytes = 10240; |
42 | ||
366f7e7a | 43 | void pstore_set_kmsg_bytes(int bytes) |
ca01d6dd | 44 | { |
366f7e7a | 45 | kmsg_bytes = bytes; |
ca01d6dd TL |
46 | } |
47 | ||
ca01d6dd TL |
48 | /* Tag each group of saved records with a sequence number */ |
49 | static int oopscount; | |
50 | ||
9f6af27f TL |
51 | static char *reason_str[] = { |
52 | "Oops", "Panic", "Kexec", "Restart", "Halt", "Poweroff", "Emergency" | |
53 | }; | |
54 | ||
ca01d6dd TL |
55 | /* |
56 | * callback from kmsg_dump. (s2,l2) has the most recently | |
57 | * written bytes, older bytes are in (s1,l1). Save as much | |
58 | * as we can from the end of the buffer. | |
59 | */ | |
60 | static void pstore_dump(struct kmsg_dumper *dumper, | |
61 | enum kmsg_dump_reason reason, | |
62 | const char *s1, unsigned long l1, | |
63 | const char *s2, unsigned long l2) | |
64 | { | |
65 | unsigned long s1_start, s2_start; | |
66 | unsigned long l1_cpy, l2_cpy; | |
67 | unsigned long size, total = 0; | |
9f6af27f | 68 | char *dst, *why; |
ca01d6dd TL |
69 | u64 id; |
70 | int hsize, part = 1; | |
71 | ||
9f6af27f TL |
72 | if (reason < ARRAY_SIZE(reason_str)) |
73 | why = reason_str[reason]; | |
74 | else | |
75 | why = "Unknown"; | |
76 | ||
ca01d6dd TL |
77 | mutex_lock(&psinfo->buf_mutex); |
78 | oopscount++; | |
79 | while (total < kmsg_bytes) { | |
80 | dst = psinfo->buf; | |
9f6af27f | 81 | hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part++); |
ca01d6dd TL |
82 | size = psinfo->bufsize - hsize; |
83 | dst += hsize; | |
84 | ||
85 | l2_cpy = min(l2, size); | |
86 | l1_cpy = min(l1, size - l2_cpy); | |
87 | ||
88 | if (l1_cpy + l2_cpy == 0) | |
89 | break; | |
90 | ||
91 | s2_start = l2 - l2_cpy; | |
92 | s1_start = l1 - l1_cpy; | |
93 | ||
94 | memcpy(dst, s1 + s1_start, l1_cpy); | |
95 | memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy); | |
96 | ||
97 | id = psinfo->write(PSTORE_TYPE_DMESG, hsize + l1_cpy + l2_cpy); | |
9f6af27f | 98 | if (reason == KMSG_DUMP_OOPS && pstore_is_mounted()) |
ca01d6dd TL |
99 | pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id, |
100 | psinfo->buf, hsize + l1_cpy + l2_cpy, | |
101 | CURRENT_TIME, psinfo->erase); | |
102 | l1 -= l1_cpy; | |
103 | l2 -= l2_cpy; | |
104 | total += l1_cpy + l2_cpy; | |
105 | } | |
106 | mutex_unlock(&psinfo->buf_mutex); | |
107 | } | |
108 | ||
109 | static struct kmsg_dumper pstore_dumper = { | |
110 | .dump = pstore_dump, | |
111 | }; | |
112 | ||
113 | /* | |
114 | * platform specific persistent storage driver registers with | |
115 | * us here. If pstore is already mounted, call the platform | |
116 | * read function right away to populate the file system. If not | |
117 | * then the pstore mount code will call us later to fill out | |
118 | * the file system. | |
119 | * | |
120 | * Register with kmsg_dump to save last part of console log on panic. | |
121 | */ | |
122 | int pstore_register(struct pstore_info *psi) | |
123 | { | |
124 | struct module *owner = psi->owner; | |
125 | ||
126 | spin_lock(&pstore_lock); | |
127 | if (psinfo) { | |
128 | spin_unlock(&pstore_lock); | |
129 | return -EBUSY; | |
130 | } | |
131 | psinfo = psi; | |
132 | spin_unlock(&pstore_lock); | |
133 | ||
134 | if (owner && !try_module_get(owner)) { | |
135 | psinfo = NULL; | |
136 | return -EINVAL; | |
137 | } | |
138 | ||
139 | if (pstore_is_mounted()) | |
140 | pstore_get_records(); | |
141 | ||
142 | kmsg_dump_register(&pstore_dumper); | |
143 | ||
144 | return 0; | |
145 | } | |
146 | EXPORT_SYMBOL_GPL(pstore_register); | |
147 | ||
148 | /* | |
149 | * Read all the records from the persistent store. Create and | |
150 | * file files in our filesystem. | |
151 | */ | |
152 | void pstore_get_records(void) | |
153 | { | |
154 | struct pstore_info *psi = psinfo; | |
8d38d74b | 155 | ssize_t size; |
ca01d6dd TL |
156 | u64 id; |
157 | enum pstore_type_id type; | |
158 | struct timespec time; | |
06cf91b4 | 159 | int failed = 0, rc; |
ca01d6dd TL |
160 | |
161 | if (!psi) | |
162 | return; | |
163 | ||
164 | mutex_lock(&psinfo->buf_mutex); | |
06cf91b4 CG |
165 | rc = psi->open(psi); |
166 | if (rc) | |
167 | goto out; | |
168 | ||
ca01d6dd | 169 | while ((size = psi->read(&id, &type, &time)) > 0) { |
8d38d74b | 170 | if (pstore_mkfile(type, psi->name, id, psi->buf, (size_t)size, |
ca01d6dd TL |
171 | time, psi->erase)) |
172 | failed++; | |
173 | } | |
06cf91b4 CG |
174 | psi->close(psi); |
175 | out: | |
ca01d6dd TL |
176 | mutex_unlock(&psinfo->buf_mutex); |
177 | ||
178 | if (failed) | |
179 | printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n", | |
180 | failed, psi->name); | |
181 | } | |
182 | ||
183 | /* | |
184 | * Call platform driver to write a record to the | |
185 | * persistent store. | |
186 | */ | |
187 | int pstore_write(enum pstore_type_id type, char *buf, size_t size) | |
188 | { | |
189 | u64 id; | |
190 | ||
191 | if (!psinfo) | |
192 | return -ENODEV; | |
193 | ||
194 | if (size > psinfo->bufsize) | |
195 | return -EFBIG; | |
196 | ||
197 | mutex_lock(&psinfo->buf_mutex); | |
198 | memcpy(psinfo->buf, buf, size); | |
199 | id = psinfo->write(type, size); | |
200 | if (pstore_is_mounted()) | |
201 | pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id, psinfo->buf, | |
202 | size, CURRENT_TIME, psinfo->erase); | |
203 | mutex_unlock(&psinfo->buf_mutex); | |
204 | ||
205 | return 0; | |
206 | } | |
207 | EXPORT_SYMBOL_GPL(pstore_write); |