Loading...
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2012 Google, Inc.
4 */
5
6#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
7
8#include <linux/device.h>
9#include <linux/err.h>
10#include <linux/errno.h>
11#include <linux/init.h>
12#include <linux/io.h>
13#include <linux/kernel.h>
14#include <linux/list.h>
15#include <linux/memblock.h>
16#include <linux/pstore_ram.h>
17#include <linux/rslib.h>
18#include <linux/slab.h>
19#include <linux/uaccess.h>
20#include <linux/vmalloc.h>
21#include <asm/page.h>
22
23/**
24 * struct persistent_ram_buffer - persistent circular RAM buffer
25 *
26 * @sig:
27 * signature to indicate header (PERSISTENT_RAM_SIG xor PRZ-type value)
28 * @start:
29 * offset into @data where the beginning of the stored bytes begin
30 * @size:
31 * number of valid bytes stored in @data
32 */
33struct persistent_ram_buffer {
34 uint32_t sig;
35 atomic_t start;
36 atomic_t size;
37 uint8_t data[0];
38};
39
40#define PERSISTENT_RAM_SIG (0x43474244) /* DBGC */
41
42static inline size_t buffer_size(struct persistent_ram_zone *prz)
43{
44 return atomic_read(&prz->buffer->size);
45}
46
47static inline size_t buffer_start(struct persistent_ram_zone *prz)
48{
49 return atomic_read(&prz->buffer->start);
50}
51
52/* increase and wrap the start pointer, returning the old value */
53static size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a)
54{
55 int old;
56 int new;
57 unsigned long flags = 0;
58
59 if (!(prz->flags & PRZ_FLAG_NO_LOCK))
60 raw_spin_lock_irqsave(&prz->buffer_lock, flags);
61
62 old = atomic_read(&prz->buffer->start);
63 new = old + a;
64 while (unlikely(new >= prz->buffer_size))
65 new -= prz->buffer_size;
66 atomic_set(&prz->buffer->start, new);
67
68 if (!(prz->flags & PRZ_FLAG_NO_LOCK))
69 raw_spin_unlock_irqrestore(&prz->buffer_lock, flags);
70
71 return old;
72}
73
74/* increase the size counter until it hits the max size */
75static void buffer_size_add(struct persistent_ram_zone *prz, size_t a)
76{
77 size_t old;
78 size_t new;
79 unsigned long flags = 0;
80
81 if (!(prz->flags & PRZ_FLAG_NO_LOCK))
82 raw_spin_lock_irqsave(&prz->buffer_lock, flags);
83
84 old = atomic_read(&prz->buffer->size);
85 if (old == prz->buffer_size)
86 goto exit;
87
88 new = old + a;
89 if (new > prz->buffer_size)
90 new = prz->buffer_size;
91 atomic_set(&prz->buffer->size, new);
92
93exit:
94 if (!(prz->flags & PRZ_FLAG_NO_LOCK))
95 raw_spin_unlock_irqrestore(&prz->buffer_lock, flags);
96}
97
98static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
99 uint8_t *data, size_t len, uint8_t *ecc)
100{
101 int i;
102
103 /* Initialize the parity buffer */
104 memset(prz->ecc_info.par, 0,
105 prz->ecc_info.ecc_size * sizeof(prz->ecc_info.par[0]));
106 encode_rs8(prz->rs_decoder, data, len, prz->ecc_info.par, 0);
107 for (i = 0; i < prz->ecc_info.ecc_size; i++)
108 ecc[i] = prz->ecc_info.par[i];
109}
110
111static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz,
112 void *data, size_t len, uint8_t *ecc)
113{
114 int i;
115
116 for (i = 0; i < prz->ecc_info.ecc_size; i++)
117 prz->ecc_info.par[i] = ecc[i];
118 return decode_rs8(prz->rs_decoder, data, prz->ecc_info.par, len,
119 NULL, 0, NULL, 0, NULL);
120}
121
122static void notrace persistent_ram_update_ecc(struct persistent_ram_zone *prz,
123 unsigned int start, unsigned int count)
124{
125 struct persistent_ram_buffer *buffer = prz->buffer;
126 uint8_t *buffer_end = buffer->data + prz->buffer_size;
127 uint8_t *block;
128 uint8_t *par;
129 int ecc_block_size = prz->ecc_info.block_size;
130 int ecc_size = prz->ecc_info.ecc_size;
131 int size = ecc_block_size;
132
133 if (!ecc_size)
134 return;
135
136 block = buffer->data + (start & ~(ecc_block_size - 1));
137 par = prz->par_buffer + (start / ecc_block_size) * ecc_size;
138
139 do {
140 if (block + ecc_block_size > buffer_end)
141 size = buffer_end - block;
142 persistent_ram_encode_rs8(prz, block, size, par);
143 block += ecc_block_size;
144 par += ecc_size;
145 } while (block < buffer->data + start + count);
146}
147
148static void persistent_ram_update_header_ecc(struct persistent_ram_zone *prz)
149{
150 struct persistent_ram_buffer *buffer = prz->buffer;
151
152 if (!prz->ecc_info.ecc_size)
153 return;
154
155 persistent_ram_encode_rs8(prz, (uint8_t *)buffer, sizeof(*buffer),
156 prz->par_header);
157}
158
159static void persistent_ram_ecc_old(struct persistent_ram_zone *prz)
160{
161 struct persistent_ram_buffer *buffer = prz->buffer;
162 uint8_t *block;
163 uint8_t *par;
164
165 if (!prz->ecc_info.ecc_size)
166 return;
167
168 block = buffer->data;
169 par = prz->par_buffer;
170 while (block < buffer->data + buffer_size(prz)) {
171 int numerr;
172 int size = prz->ecc_info.block_size;
173 if (block + size > buffer->data + prz->buffer_size)
174 size = buffer->data + prz->buffer_size - block;
175 numerr = persistent_ram_decode_rs8(prz, block, size, par);
176 if (numerr > 0) {
177 pr_devel("error in block %p, %d\n", block, numerr);
178 prz->corrected_bytes += numerr;
179 } else if (numerr < 0) {
180 pr_devel("uncorrectable error in block %p\n", block);
181 prz->bad_blocks++;
182 }
183 block += prz->ecc_info.block_size;
184 par += prz->ecc_info.ecc_size;
185 }
186}
187
188static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
189 struct persistent_ram_ecc_info *ecc_info)
190{
191 int numerr;
192 struct persistent_ram_buffer *buffer = prz->buffer;
193 int ecc_blocks;
194 size_t ecc_total;
195
196 if (!ecc_info || !ecc_info->ecc_size)
197 return 0;
198
199 prz->ecc_info.block_size = ecc_info->block_size ?: 128;
200 prz->ecc_info.ecc_size = ecc_info->ecc_size ?: 16;
201 prz->ecc_info.symsize = ecc_info->symsize ?: 8;
202 prz->ecc_info.poly = ecc_info->poly ?: 0x11d;
203
204 ecc_blocks = DIV_ROUND_UP(prz->buffer_size - prz->ecc_info.ecc_size,
205 prz->ecc_info.block_size +
206 prz->ecc_info.ecc_size);
207 ecc_total = (ecc_blocks + 1) * prz->ecc_info.ecc_size;
208 if (ecc_total >= prz->buffer_size) {
209 pr_err("%s: invalid ecc_size %u (total %zu, buffer size %zu)\n",
210 __func__, prz->ecc_info.ecc_size,
211 ecc_total, prz->buffer_size);
212 return -EINVAL;
213 }
214
215 prz->buffer_size -= ecc_total;
216 prz->par_buffer = buffer->data + prz->buffer_size;
217 prz->par_header = prz->par_buffer +
218 ecc_blocks * prz->ecc_info.ecc_size;
219
220 /*
221 * first consecutive root is 0
222 * primitive element to generate roots = 1
223 */
224 prz->rs_decoder = init_rs(prz->ecc_info.symsize, prz->ecc_info.poly,
225 0, 1, prz->ecc_info.ecc_size);
226 if (prz->rs_decoder == NULL) {
227 pr_info("init_rs failed\n");
228 return -EINVAL;
229 }
230
231 /* allocate workspace instead of using stack VLA */
232 prz->ecc_info.par = kmalloc_array(prz->ecc_info.ecc_size,
233 sizeof(*prz->ecc_info.par),
234 GFP_KERNEL);
235 if (!prz->ecc_info.par) {
236 pr_err("cannot allocate ECC parity workspace\n");
237 return -ENOMEM;
238 }
239
240 prz->corrected_bytes = 0;
241 prz->bad_blocks = 0;
242
243 numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer),
244 prz->par_header);
245 if (numerr > 0) {
246 pr_info("error in header, %d\n", numerr);
247 prz->corrected_bytes += numerr;
248 } else if (numerr < 0) {
249 pr_info("uncorrectable error in header\n");
250 prz->bad_blocks++;
251 }
252
253 return 0;
254}
255
256ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
257 char *str, size_t len)
258{
259 ssize_t ret;
260
261 if (!prz->ecc_info.ecc_size)
262 return 0;
263
264 if (prz->corrected_bytes || prz->bad_blocks)
265 ret = snprintf(str, len, ""
266 "\n%d Corrected bytes, %d unrecoverable blocks\n",
267 prz->corrected_bytes, prz->bad_blocks);
268 else
269 ret = snprintf(str, len, "\nNo errors detected\n");
270
271 return ret;
272}
273
274static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
275 const void *s, unsigned int start, unsigned int count)
276{
277 struct persistent_ram_buffer *buffer = prz->buffer;
278 memcpy_toio(buffer->data + start, s, count);
279 persistent_ram_update_ecc(prz, start, count);
280}
281
282static int notrace persistent_ram_update_user(struct persistent_ram_zone *prz,
283 const void __user *s, unsigned int start, unsigned int count)
284{
285 struct persistent_ram_buffer *buffer = prz->buffer;
286 int ret = unlikely(__copy_from_user(buffer->data + start, s, count)) ?
287 -EFAULT : 0;
288 persistent_ram_update_ecc(prz, start, count);
289 return ret;
290}
291
292void persistent_ram_save_old(struct persistent_ram_zone *prz)
293{
294 struct persistent_ram_buffer *buffer = prz->buffer;
295 size_t size = buffer_size(prz);
296 size_t start = buffer_start(prz);
297
298 if (!size)
299 return;
300
301 if (!prz->old_log) {
302 persistent_ram_ecc_old(prz);
303 prz->old_log = kmalloc(size, GFP_KERNEL);
304 }
305 if (!prz->old_log) {
306 pr_err("failed to allocate buffer\n");
307 return;
308 }
309
310 prz->old_log_size = size;
311 memcpy_fromio(prz->old_log, &buffer->data[start], size - start);
312 memcpy_fromio(prz->old_log + size - start, &buffer->data[0], start);
313}
314
315int notrace persistent_ram_write(struct persistent_ram_zone *prz,
316 const void *s, unsigned int count)
317{
318 int rem;
319 int c = count;
320 size_t start;
321
322 if (unlikely(c > prz->buffer_size)) {
323 s += c - prz->buffer_size;
324 c = prz->buffer_size;
325 }
326
327 buffer_size_add(prz, c);
328
329 start = buffer_start_add(prz, c);
330
331 rem = prz->buffer_size - start;
332 if (unlikely(rem < c)) {
333 persistent_ram_update(prz, s, start, rem);
334 s += rem;
335 c -= rem;
336 start = 0;
337 }
338 persistent_ram_update(prz, s, start, c);
339
340 persistent_ram_update_header_ecc(prz);
341
342 return count;
343}
344
345int notrace persistent_ram_write_user(struct persistent_ram_zone *prz,
346 const void __user *s, unsigned int count)
347{
348 int rem, ret = 0, c = count;
349 size_t start;
350
351 if (unlikely(!access_ok(s, count)))
352 return -EFAULT;
353 if (unlikely(c > prz->buffer_size)) {
354 s += c - prz->buffer_size;
355 c = prz->buffer_size;
356 }
357
358 buffer_size_add(prz, c);
359
360 start = buffer_start_add(prz, c);
361
362 rem = prz->buffer_size - start;
363 if (unlikely(rem < c)) {
364 ret = persistent_ram_update_user(prz, s, start, rem);
365 s += rem;
366 c -= rem;
367 start = 0;
368 }
369 if (likely(!ret))
370 ret = persistent_ram_update_user(prz, s, start, c);
371
372 persistent_ram_update_header_ecc(prz);
373
374 return unlikely(ret) ? ret : count;
375}
376
377size_t persistent_ram_old_size(struct persistent_ram_zone *prz)
378{
379 return prz->old_log_size;
380}
381
382void *persistent_ram_old(struct persistent_ram_zone *prz)
383{
384 return prz->old_log;
385}
386
387void persistent_ram_free_old(struct persistent_ram_zone *prz)
388{
389 kfree(prz->old_log);
390 prz->old_log = NULL;
391 prz->old_log_size = 0;
392}
393
394void persistent_ram_zap(struct persistent_ram_zone *prz)
395{
396 atomic_set(&prz->buffer->start, 0);
397 atomic_set(&prz->buffer->size, 0);
398 persistent_ram_update_header_ecc(prz);
399}
400
401static void *persistent_ram_vmap(phys_addr_t start, size_t size,
402 unsigned int memtype)
403{
404 struct page **pages;
405 phys_addr_t page_start;
406 unsigned int page_count;
407 pgprot_t prot;
408 unsigned int i;
409 void *vaddr;
410
411 page_start = start - offset_in_page(start);
412 page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);
413
414 if (memtype)
415 prot = pgprot_noncached(PAGE_KERNEL);
416 else
417 prot = pgprot_writecombine(PAGE_KERNEL);
418
419 pages = kmalloc_array(page_count, sizeof(struct page *), GFP_KERNEL);
420 if (!pages) {
421 pr_err("%s: Failed to allocate array for %u pages\n",
422 __func__, page_count);
423 return NULL;
424 }
425
426 for (i = 0; i < page_count; i++) {
427 phys_addr_t addr = page_start + i * PAGE_SIZE;
428 pages[i] = pfn_to_page(addr >> PAGE_SHIFT);
429 }
430 vaddr = vmap(pages, page_count, VM_MAP, prot);
431 kfree(pages);
432
433 /*
434 * Since vmap() uses page granularity, we must add the offset
435 * into the page here, to get the byte granularity address
436 * into the mapping to represent the actual "start" location.
437 */
438 return vaddr + offset_in_page(start);
439}
440
441static void *persistent_ram_iomap(phys_addr_t start, size_t size,
442 unsigned int memtype, char *label)
443{
444 void *va;
445
446 if (!request_mem_region(start, size, label ?: "ramoops")) {
447 pr_err("request mem region (%s 0x%llx@0x%llx) failed\n",
448 label ?: "ramoops",
449 (unsigned long long)size, (unsigned long long)start);
450 return NULL;
451 }
452
453 if (memtype)
454 va = ioremap(start, size);
455 else
456 va = ioremap_wc(start, size);
457
458 /*
459 * Since request_mem_region() and ioremap() are byte-granularity
460 * there is no need handle anything special like we do when the
461 * vmap() case in persistent_ram_vmap() above.
462 */
463 return va;
464}
465
466static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
467 struct persistent_ram_zone *prz, int memtype)
468{
469 prz->paddr = start;
470 prz->size = size;
471
472 if (pfn_valid(start >> PAGE_SHIFT))
473 prz->vaddr = persistent_ram_vmap(start, size, memtype);
474 else
475 prz->vaddr = persistent_ram_iomap(start, size, memtype,
476 prz->label);
477
478 if (!prz->vaddr) {
479 pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__,
480 (unsigned long long)size, (unsigned long long)start);
481 return -ENOMEM;
482 }
483
484 prz->buffer = prz->vaddr;
485 prz->buffer_size = size - sizeof(struct persistent_ram_buffer);
486
487 return 0;
488}
489
490static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig,
491 struct persistent_ram_ecc_info *ecc_info)
492{
493 int ret;
494 bool zap = !!(prz->flags & PRZ_FLAG_ZAP_OLD);
495
496 ret = persistent_ram_init_ecc(prz, ecc_info);
497 if (ret) {
498 pr_warn("ECC failed %s\n", prz->label);
499 return ret;
500 }
501
502 sig ^= PERSISTENT_RAM_SIG;
503
504 if (prz->buffer->sig == sig) {
505 if (buffer_size(prz) == 0) {
506 pr_debug("found existing empty buffer\n");
507 return 0;
508 }
509
510 if (buffer_size(prz) > prz->buffer_size ||
511 buffer_start(prz) > buffer_size(prz)) {
512 pr_info("found existing invalid buffer, size %zu, start %zu\n",
513 buffer_size(prz), buffer_start(prz));
514 zap = true;
515 } else {
516 pr_debug("found existing buffer, size %zu, start %zu\n",
517 buffer_size(prz), buffer_start(prz));
518 persistent_ram_save_old(prz);
519 }
520 } else {
521 pr_debug("no valid data in buffer (sig = 0x%08x)\n",
522 prz->buffer->sig);
523 prz->buffer->sig = sig;
524 zap = true;
525 }
526
527 /* Reset missing, invalid, or single-use memory area. */
528 if (zap)
529 persistent_ram_zap(prz);
530
531 return 0;
532}
533
534void persistent_ram_free(struct persistent_ram_zone *prz)
535{
536 if (!prz)
537 return;
538
539 if (prz->vaddr) {
540 if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
541 /* We must vunmap() at page-granularity. */
542 vunmap(prz->vaddr - offset_in_page(prz->paddr));
543 } else {
544 iounmap(prz->vaddr);
545 release_mem_region(prz->paddr, prz->size);
546 }
547 prz->vaddr = NULL;
548 }
549 if (prz->rs_decoder) {
550 free_rs(prz->rs_decoder);
551 prz->rs_decoder = NULL;
552 }
553 kfree(prz->ecc_info.par);
554 prz->ecc_info.par = NULL;
555
556 persistent_ram_free_old(prz);
557 kfree(prz->label);
558 kfree(prz);
559}
560
561struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
562 u32 sig, struct persistent_ram_ecc_info *ecc_info,
563 unsigned int memtype, u32 flags, char *label)
564{
565 struct persistent_ram_zone *prz;
566 int ret = -ENOMEM;
567
568 prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
569 if (!prz) {
570 pr_err("failed to allocate persistent ram zone\n");
571 goto err;
572 }
573
574 /* Initialize general buffer state. */
575 raw_spin_lock_init(&prz->buffer_lock);
576 prz->flags = flags;
577 prz->label = label;
578
579 ret = persistent_ram_buffer_map(start, size, prz, memtype);
580 if (ret)
581 goto err;
582
583 ret = persistent_ram_post_init(prz, sig, ecc_info);
584 if (ret)
585 goto err;
586
587 pr_debug("attached %s 0x%zx@0x%llx: %zu header, %zu data, %zu ecc (%d/%d)\n",
588 prz->label, prz->size, (unsigned long long)prz->paddr,
589 sizeof(*prz->buffer), prz->buffer_size,
590 prz->size - sizeof(*prz->buffer) - prz->buffer_size,
591 prz->ecc_info.ecc_size, prz->ecc_info.block_size);
592
593 return prz;
594err:
595 persistent_ram_free(prz);
596 return ERR_PTR(ret);
597}
1/*
2 * Copyright (C) 2012 Google, Inc.
3 *
4 * This software is licensed under the terms of the GNU General Public
5 * License version 2, as published by the Free Software Foundation, and
6 * may be copied, distributed, and modified under those terms.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 */
14
15#define pr_fmt(fmt) "persistent_ram: " fmt
16
17#include <linux/device.h>
18#include <linux/err.h>
19#include <linux/errno.h>
20#include <linux/kernel.h>
21#include <linux/init.h>
22#include <linux/io.h>
23#include <linux/list.h>
24#include <linux/memblock.h>
25#include <linux/rslib.h>
26#include <linux/slab.h>
27#include <linux/vmalloc.h>
28#include <linux/pstore_ram.h>
29#include <asm/page.h>
30
31struct persistent_ram_buffer {
32 uint32_t sig;
33 atomic_t start;
34 atomic_t size;
35 uint8_t data[0];
36};
37
38#define PERSISTENT_RAM_SIG (0x43474244) /* DBGC */
39
40static inline size_t buffer_size(struct persistent_ram_zone *prz)
41{
42 return atomic_read(&prz->buffer->size);
43}
44
45static inline size_t buffer_start(struct persistent_ram_zone *prz)
46{
47 return atomic_read(&prz->buffer->start);
48}
49
50/* increase and wrap the start pointer, returning the old value */
51static size_t buffer_start_add_atomic(struct persistent_ram_zone *prz, size_t a)
52{
53 int old;
54 int new;
55
56 do {
57 old = atomic_read(&prz->buffer->start);
58 new = old + a;
59 while (unlikely(new >= prz->buffer_size))
60 new -= prz->buffer_size;
61 } while (atomic_cmpxchg(&prz->buffer->start, old, new) != old);
62
63 return old;
64}
65
66/* increase the size counter until it hits the max size */
67static void buffer_size_add_atomic(struct persistent_ram_zone *prz, size_t a)
68{
69 size_t old;
70 size_t new;
71
72 if (atomic_read(&prz->buffer->size) == prz->buffer_size)
73 return;
74
75 do {
76 old = atomic_read(&prz->buffer->size);
77 new = old + a;
78 if (new > prz->buffer_size)
79 new = prz->buffer_size;
80 } while (atomic_cmpxchg(&prz->buffer->size, old, new) != old);
81}
82
83static DEFINE_RAW_SPINLOCK(buffer_lock);
84
85/* increase and wrap the start pointer, returning the old value */
86static size_t buffer_start_add_locked(struct persistent_ram_zone *prz, size_t a)
87{
88 int old;
89 int new;
90 unsigned long flags;
91
92 raw_spin_lock_irqsave(&buffer_lock, flags);
93
94 old = atomic_read(&prz->buffer->start);
95 new = old + a;
96 while (unlikely(new >= prz->buffer_size))
97 new -= prz->buffer_size;
98 atomic_set(&prz->buffer->start, new);
99
100 raw_spin_unlock_irqrestore(&buffer_lock, flags);
101
102 return old;
103}
104
105/* increase the size counter until it hits the max size */
106static void buffer_size_add_locked(struct persistent_ram_zone *prz, size_t a)
107{
108 size_t old;
109 size_t new;
110 unsigned long flags;
111
112 raw_spin_lock_irqsave(&buffer_lock, flags);
113
114 old = atomic_read(&prz->buffer->size);
115 if (old == prz->buffer_size)
116 goto exit;
117
118 new = old + a;
119 if (new > prz->buffer_size)
120 new = prz->buffer_size;
121 atomic_set(&prz->buffer->size, new);
122
123exit:
124 raw_spin_unlock_irqrestore(&buffer_lock, flags);
125}
126
127static size_t (*buffer_start_add)(struct persistent_ram_zone *, size_t) = buffer_start_add_atomic;
128static void (*buffer_size_add)(struct persistent_ram_zone *, size_t) = buffer_size_add_atomic;
129
130static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
131 uint8_t *data, size_t len, uint8_t *ecc)
132{
133 int i;
134 uint16_t par[prz->ecc_info.ecc_size];
135
136 /* Initialize the parity buffer */
137 memset(par, 0, sizeof(par));
138 encode_rs8(prz->rs_decoder, data, len, par, 0);
139 for (i = 0; i < prz->ecc_info.ecc_size; i++)
140 ecc[i] = par[i];
141}
142
143static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz,
144 void *data, size_t len, uint8_t *ecc)
145{
146 int i;
147 uint16_t par[prz->ecc_info.ecc_size];
148
149 for (i = 0; i < prz->ecc_info.ecc_size; i++)
150 par[i] = ecc[i];
151 return decode_rs8(prz->rs_decoder, data, par, len,
152 NULL, 0, NULL, 0, NULL);
153}
154
155static void notrace persistent_ram_update_ecc(struct persistent_ram_zone *prz,
156 unsigned int start, unsigned int count)
157{
158 struct persistent_ram_buffer *buffer = prz->buffer;
159 uint8_t *buffer_end = buffer->data + prz->buffer_size;
160 uint8_t *block;
161 uint8_t *par;
162 int ecc_block_size = prz->ecc_info.block_size;
163 int ecc_size = prz->ecc_info.ecc_size;
164 int size = ecc_block_size;
165
166 if (!ecc_size)
167 return;
168
169 block = buffer->data + (start & ~(ecc_block_size - 1));
170 par = prz->par_buffer + (start / ecc_block_size) * ecc_size;
171
172 do {
173 if (block + ecc_block_size > buffer_end)
174 size = buffer_end - block;
175 persistent_ram_encode_rs8(prz, block, size, par);
176 block += ecc_block_size;
177 par += ecc_size;
178 } while (block < buffer->data + start + count);
179}
180
181static void persistent_ram_update_header_ecc(struct persistent_ram_zone *prz)
182{
183 struct persistent_ram_buffer *buffer = prz->buffer;
184
185 if (!prz->ecc_info.ecc_size)
186 return;
187
188 persistent_ram_encode_rs8(prz, (uint8_t *)buffer, sizeof(*buffer),
189 prz->par_header);
190}
191
192static void persistent_ram_ecc_old(struct persistent_ram_zone *prz)
193{
194 struct persistent_ram_buffer *buffer = prz->buffer;
195 uint8_t *block;
196 uint8_t *par;
197
198 if (!prz->ecc_info.ecc_size)
199 return;
200
201 block = buffer->data;
202 par = prz->par_buffer;
203 while (block < buffer->data + buffer_size(prz)) {
204 int numerr;
205 int size = prz->ecc_info.block_size;
206 if (block + size > buffer->data + prz->buffer_size)
207 size = buffer->data + prz->buffer_size - block;
208 numerr = persistent_ram_decode_rs8(prz, block, size, par);
209 if (numerr > 0) {
210 pr_devel("error in block %p, %d\n", block, numerr);
211 prz->corrected_bytes += numerr;
212 } else if (numerr < 0) {
213 pr_devel("uncorrectable error in block %p\n", block);
214 prz->bad_blocks++;
215 }
216 block += prz->ecc_info.block_size;
217 par += prz->ecc_info.ecc_size;
218 }
219}
220
221static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
222 struct persistent_ram_ecc_info *ecc_info)
223{
224 int numerr;
225 struct persistent_ram_buffer *buffer = prz->buffer;
226 int ecc_blocks;
227 size_t ecc_total;
228
229 if (!ecc_info || !ecc_info->ecc_size)
230 return 0;
231
232 prz->ecc_info.block_size = ecc_info->block_size ?: 128;
233 prz->ecc_info.ecc_size = ecc_info->ecc_size ?: 16;
234 prz->ecc_info.symsize = ecc_info->symsize ?: 8;
235 prz->ecc_info.poly = ecc_info->poly ?: 0x11d;
236
237 ecc_blocks = DIV_ROUND_UP(prz->buffer_size - prz->ecc_info.ecc_size,
238 prz->ecc_info.block_size +
239 prz->ecc_info.ecc_size);
240 ecc_total = (ecc_blocks + 1) * prz->ecc_info.ecc_size;
241 if (ecc_total >= prz->buffer_size) {
242 pr_err("%s: invalid ecc_size %u (total %zu, buffer size %zu)\n",
243 __func__, prz->ecc_info.ecc_size,
244 ecc_total, prz->buffer_size);
245 return -EINVAL;
246 }
247
248 prz->buffer_size -= ecc_total;
249 prz->par_buffer = buffer->data + prz->buffer_size;
250 prz->par_header = prz->par_buffer +
251 ecc_blocks * prz->ecc_info.ecc_size;
252
253 /*
254 * first consecutive root is 0
255 * primitive element to generate roots = 1
256 */
257 prz->rs_decoder = init_rs(prz->ecc_info.symsize, prz->ecc_info.poly,
258 0, 1, prz->ecc_info.ecc_size);
259 if (prz->rs_decoder == NULL) {
260 pr_info("init_rs failed\n");
261 return -EINVAL;
262 }
263
264 prz->corrected_bytes = 0;
265 prz->bad_blocks = 0;
266
267 numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer),
268 prz->par_header);
269 if (numerr > 0) {
270 pr_info("error in header, %d\n", numerr);
271 prz->corrected_bytes += numerr;
272 } else if (numerr < 0) {
273 pr_info("uncorrectable error in header\n");
274 prz->bad_blocks++;
275 }
276
277 return 0;
278}
279
280ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
281 char *str, size_t len)
282{
283 ssize_t ret;
284
285 if (!prz->ecc_info.ecc_size)
286 return 0;
287
288 if (prz->corrected_bytes || prz->bad_blocks)
289 ret = snprintf(str, len, ""
290 "\n%d Corrected bytes, %d unrecoverable blocks\n",
291 prz->corrected_bytes, prz->bad_blocks);
292 else
293 ret = snprintf(str, len, "\nNo errors detected\n");
294
295 return ret;
296}
297
298static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
299 const void *s, unsigned int start, unsigned int count)
300{
301 struct persistent_ram_buffer *buffer = prz->buffer;
302 memcpy(buffer->data + start, s, count);
303 persistent_ram_update_ecc(prz, start, count);
304}
305
306void persistent_ram_save_old(struct persistent_ram_zone *prz)
307{
308 struct persistent_ram_buffer *buffer = prz->buffer;
309 size_t size = buffer_size(prz);
310 size_t start = buffer_start(prz);
311
312 if (!size)
313 return;
314
315 if (!prz->old_log) {
316 persistent_ram_ecc_old(prz);
317 prz->old_log = kmalloc(size, GFP_KERNEL);
318 }
319 if (!prz->old_log) {
320 pr_err("failed to allocate buffer\n");
321 return;
322 }
323
324 prz->old_log_size = size;
325 memcpy(prz->old_log, &buffer->data[start], size - start);
326 memcpy(prz->old_log + size - start, &buffer->data[0], start);
327}
328
329int notrace persistent_ram_write(struct persistent_ram_zone *prz,
330 const void *s, unsigned int count)
331{
332 int rem;
333 int c = count;
334 size_t start;
335
336 if (unlikely(c > prz->buffer_size)) {
337 s += c - prz->buffer_size;
338 c = prz->buffer_size;
339 }
340
341 buffer_size_add(prz, c);
342
343 start = buffer_start_add(prz, c);
344
345 rem = prz->buffer_size - start;
346 if (unlikely(rem < c)) {
347 persistent_ram_update(prz, s, start, rem);
348 s += rem;
349 c -= rem;
350 start = 0;
351 }
352 persistent_ram_update(prz, s, start, c);
353
354 persistent_ram_update_header_ecc(prz);
355
356 return count;
357}
358
359size_t persistent_ram_old_size(struct persistent_ram_zone *prz)
360{
361 return prz->old_log_size;
362}
363
364void *persistent_ram_old(struct persistent_ram_zone *prz)
365{
366 return prz->old_log;
367}
368
369void persistent_ram_free_old(struct persistent_ram_zone *prz)
370{
371 kfree(prz->old_log);
372 prz->old_log = NULL;
373 prz->old_log_size = 0;
374}
375
376void persistent_ram_zap(struct persistent_ram_zone *prz)
377{
378 atomic_set(&prz->buffer->start, 0);
379 atomic_set(&prz->buffer->size, 0);
380 persistent_ram_update_header_ecc(prz);
381}
382
383static void *persistent_ram_vmap(phys_addr_t start, size_t size,
384 unsigned int memtype)
385{
386 struct page **pages;
387 phys_addr_t page_start;
388 unsigned int page_count;
389 pgprot_t prot;
390 unsigned int i;
391 void *vaddr;
392
393 page_start = start - offset_in_page(start);
394 page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);
395
396 if (memtype)
397 prot = pgprot_noncached(PAGE_KERNEL);
398 else
399 prot = pgprot_writecombine(PAGE_KERNEL);
400
401 pages = kmalloc_array(page_count, sizeof(struct page *), GFP_KERNEL);
402 if (!pages) {
403 pr_err("%s: Failed to allocate array for %u pages\n",
404 __func__, page_count);
405 return NULL;
406 }
407
408 for (i = 0; i < page_count; i++) {
409 phys_addr_t addr = page_start + i * PAGE_SIZE;
410 pages[i] = pfn_to_page(addr >> PAGE_SHIFT);
411 }
412 vaddr = vmap(pages, page_count, VM_MAP, prot);
413 kfree(pages);
414
415 return vaddr;
416}
417
418static void *persistent_ram_iomap(phys_addr_t start, size_t size,
419 unsigned int memtype)
420{
421 void *va;
422
423 if (!request_mem_region(start, size, "persistent_ram")) {
424 pr_err("request mem region (0x%llx@0x%llx) failed\n",
425 (unsigned long long)size, (unsigned long long)start);
426 return NULL;
427 }
428
429 buffer_start_add = buffer_start_add_locked;
430 buffer_size_add = buffer_size_add_locked;
431
432 if (memtype)
433 va = ioremap(start, size);
434 else
435 va = ioremap_wc(start, size);
436
437 return va;
438}
439
440static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
441 struct persistent_ram_zone *prz, int memtype)
442{
443 prz->paddr = start;
444 prz->size = size;
445
446 if (pfn_valid(start >> PAGE_SHIFT))
447 prz->vaddr = persistent_ram_vmap(start, size, memtype);
448 else
449 prz->vaddr = persistent_ram_iomap(start, size, memtype);
450
451 if (!prz->vaddr) {
452 pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__,
453 (unsigned long long)size, (unsigned long long)start);
454 return -ENOMEM;
455 }
456
457 prz->buffer = prz->vaddr + offset_in_page(start);
458 prz->buffer_size = size - sizeof(struct persistent_ram_buffer);
459
460 return 0;
461}
462
463static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig,
464 struct persistent_ram_ecc_info *ecc_info)
465{
466 int ret;
467
468 ret = persistent_ram_init_ecc(prz, ecc_info);
469 if (ret)
470 return ret;
471
472 sig ^= PERSISTENT_RAM_SIG;
473
474 if (prz->buffer->sig == sig) {
475 if (buffer_size(prz) > prz->buffer_size ||
476 buffer_start(prz) > buffer_size(prz))
477 pr_info("found existing invalid buffer, size %zu, start %zu\n",
478 buffer_size(prz), buffer_start(prz));
479 else {
480 pr_debug("found existing buffer, size %zu, start %zu\n",
481 buffer_size(prz), buffer_start(prz));
482 persistent_ram_save_old(prz);
483 return 0;
484 }
485 } else {
486 pr_debug("no valid data in buffer (sig = 0x%08x)\n",
487 prz->buffer->sig);
488 }
489
490 prz->buffer->sig = sig;
491 persistent_ram_zap(prz);
492
493 return 0;
494}
495
496void persistent_ram_free(struct persistent_ram_zone *prz)
497{
498 if (!prz)
499 return;
500
501 if (prz->vaddr) {
502 if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
503 vunmap(prz->vaddr);
504 } else {
505 iounmap(prz->vaddr);
506 release_mem_region(prz->paddr, prz->size);
507 }
508 prz->vaddr = NULL;
509 }
510 persistent_ram_free_old(prz);
511 kfree(prz);
512}
513
514struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
515 u32 sig, struct persistent_ram_ecc_info *ecc_info,
516 unsigned int memtype)
517{
518 struct persistent_ram_zone *prz;
519 int ret = -ENOMEM;
520
521 prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
522 if (!prz) {
523 pr_err("failed to allocate persistent ram zone\n");
524 goto err;
525 }
526
527 ret = persistent_ram_buffer_map(start, size, prz, memtype);
528 if (ret)
529 goto err;
530
531 ret = persistent_ram_post_init(prz, sig, ecc_info);
532 if (ret)
533 goto err;
534
535 return prz;
536err:
537 persistent_ram_free(prz);
538 return ERR_PTR(ret);
539}