[linux-2.6-block.git] / drivers / mtd / mtdoops.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * MTD Oops/Panic logger
 *
 * Copyright © 2007 Nokia Corporation. All rights reserved.
 *
 * Author: Richard Purdie <rpurdie@openedhand.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/console.h>
#include <linux/vmalloc.h>
#include <linux/workqueue.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/timekeeping.h>
#include <linux/mtd/mtd.h>
#include <linux/kmsg_dump.h>

/* Maximum MTD partition size */
#define MTDOOPS_MAX_MTD_SIZE (8 * 1024 * 1024)

static unsigned long record_size = 4096;
module_param(record_size, ulong, 0400);
MODULE_PARM_DESC(record_size,
		"record size for MTD OOPS pages in bytes (default 4096)");

static char mtddev[80];
module_param_string(mtddev, mtddev, 80, 0400);
MODULE_PARM_DESC(mtddev,
		"name or index number of the MTD device to use");

static int dump_oops = 1;
module_param(dump_oops, int, 0600);
MODULE_PARM_DESC(dump_oops,
		"set to 1 to dump oopses, 0 to only dump panics (default 1)");

#define MTDOOPS_KERNMSG_MAGIC_v1 0x5d005d00  /* Original */
#define MTDOOPS_KERNMSG_MAGIC_v2 0x5d005e00  /* Adds the timestamp */

struct mtdoops_hdr {
	u32 seq;
	u32 magic;
	ktime_t timestamp;
} __packed;

static struct mtdoops_context {
	struct kmsg_dumper dump;

	int mtd_index;
	struct work_struct work_erase;
	struct work_struct work_write;
	struct mtd_info *mtd;
	int oops_pages;
	int nextpage;
	int nextcount;
	unsigned long *oops_page_used;

	unsigned long oops_buf_busy;
	void *oops_buf;
} oops_cxt;

static void mark_page_used(struct mtdoops_context *cxt, int page)
{
	set_bit(page, cxt->oops_page_used);
}

static void mark_page_unused(struct mtdoops_context *cxt, int page)
{
	clear_bit(page, cxt->oops_page_used);
}

static int page_is_used(struct mtdoops_context *cxt, int page)
{
	return test_bit(page, cxt->oops_page_used);
}

static int mtdoops_erase_block(struct mtdoops_context *cxt, int offset)
{
	struct mtd_info *mtd = cxt->mtd;
	u32 start_page_offset = mtd_div_by_eb(offset, mtd) * mtd->erasesize;
	u32 start_page = start_page_offset / record_size;
	u32 erase_pages = mtd->erasesize / record_size;
	struct erase_info erase;
	int ret;
	int page;

	erase.addr = offset;
	erase.len = mtd->erasesize;

	ret = mtd_erase(mtd, &erase);
	if (ret) {
		pr_warn("erase of region [0x%llx, 0x%llx] on \"%s\" failed\n",
			(unsigned long long)erase.addr,
			(unsigned long long)erase.len, mtddev);
		return ret;
	}

	/* Mark pages as unused */
	for (page = start_page; page < start_page + erase_pages; page++)
		mark_page_unused(cxt, page);

	return 0;
}

static void mtdoops_erase(struct mtdoops_context *cxt)
{
	struct mtd_info *mtd = cxt->mtd;
	int i = 0, j, ret, mod;

	/* We were unregistered */
	if (!mtd)
		return;

	mod = (cxt->nextpage * record_size) % mtd->erasesize;
	if (mod != 0) {
		cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / record_size);
		if (cxt->nextpage >= cxt->oops_pages)
			cxt->nextpage = 0;
	}

	while ((ret = mtd_block_isbad(mtd, cxt->nextpage * record_size)) > 0) {
badblock:
		pr_warn("bad block at %08lx\n",
			cxt->nextpage * record_size);
		i++;
		cxt->nextpage = cxt->nextpage + (mtd->erasesize / record_size);
		if (cxt->nextpage >= cxt->oops_pages)
			cxt->nextpage = 0;
		if (i == cxt->oops_pages / (mtd->erasesize / record_size)) {
			pr_err("all blocks bad!\n");
			return;
		}
	}

	if (ret < 0) {
		pr_err("mtd_block_isbad failed, aborting\n");
		return;
	}

	for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
		ret = mtdoops_erase_block(cxt, cxt->nextpage * record_size);

	if (ret >= 0) {
		pr_debug("ready %d, %d\n",
			 cxt->nextpage, cxt->nextcount);
		return;
	}

	if (ret == -EIO) {
		ret = mtd_block_markbad(mtd, cxt->nextpage * record_size);
		if (ret < 0 && ret != -EOPNOTSUPP) {
			pr_err("block_markbad failed, aborting\n");
			return;
		}
	}
	goto badblock;
}

/* Scheduled work - when we can't proceed without erasing a block */
static void mtdoops_workfunc_erase(struct work_struct *work)
{
	struct mtdoops_context *cxt =
			container_of(work, struct mtdoops_context, work_erase);
	mtdoops_erase(cxt);
}

static void mtdoops_inc_counter(struct mtdoops_context *cxt, int panic)
{
	cxt->nextpage++;
	if (cxt->nextpage >= cxt->oops_pages)
		cxt->nextpage = 0;
	cxt->nextcount++;
	if (cxt->nextcount == 0xffffffff)
		cxt->nextcount = 0;

	if (page_is_used(cxt, cxt->nextpage)) {
		pr_debug("not ready %d, %d (erase %s)\n",
			 cxt->nextpage, cxt->nextcount,
			 panic ? "immediately" : "scheduled");
		if (panic) {
			/* In case of panic, erase immediately */
			mtdoops_erase(cxt);
		} else {
			/* Otherwise, schedule work to erase it "nicely" */
			schedule_work(&cxt->work_erase);
		}
	} else {
		pr_debug("ready %d, %d (no erase)\n",
			 cxt->nextpage, cxt->nextcount);
	}
}

static void mtdoops_write(struct mtdoops_context *cxt, int panic)
{
	struct mtd_info *mtd = cxt->mtd;
	size_t retlen;
	struct mtdoops_hdr *hdr;
	int ret;

	if (test_and_set_bit(0, &cxt->oops_buf_busy))
		return;

	/* Add mtdoops header to the buffer */
	hdr = (struct mtdoops_hdr *)cxt->oops_buf;
	hdr->seq = cxt->nextcount;
	hdr->magic = MTDOOPS_KERNMSG_MAGIC_v2;
	hdr->timestamp = ktime_get_real();

	if (panic) {
		ret = mtd_panic_write(mtd, cxt->nextpage * record_size,
				      record_size, &retlen, cxt->oops_buf);
		if (ret == -EOPNOTSUPP) {
			pr_err("Cannot write from panic without panic_write\n");
			goto out;
		}
	} else
		ret = mtd_write(mtd, cxt->nextpage * record_size,
				record_size, &retlen, cxt->oops_buf);

	if (retlen != record_size || ret < 0)
		pr_err("write failure at %ld (%td of %ld written), error %d\n",
		       cxt->nextpage * record_size, retlen, record_size, ret);
	mark_page_used(cxt, cxt->nextpage);
	memset(cxt->oops_buf, 0xff, record_size);

	mtdoops_inc_counter(cxt, panic);
out:
	clear_bit(0, &cxt->oops_buf_busy);
}

static void mtdoops_workfunc_write(struct work_struct *work)
{
	struct mtdoops_context *cxt =
			container_of(work, struct mtdoops_context, work_write);

	mtdoops_write(cxt, 0);
}

static void find_next_position(struct mtdoops_context *cxt)
{
	struct mtd_info *mtd = cxt->mtd;
	struct mtdoops_hdr hdr;
	int ret, page, maxpos = 0;
	u32 maxcount = 0xffffffff;
	size_t retlen;

	for (page = 0; page < cxt->oops_pages; page++) {
		if (mtd_block_isbad(mtd, page * record_size))
			continue;
		/* Assume the page is used */
		mark_page_used(cxt, page);
		ret = mtd_read(mtd, page * record_size, sizeof(hdr),
			       &retlen, (u_char *)&hdr);
		if (retlen != sizeof(hdr) ||
				(ret < 0 && !mtd_is_bitflip(ret))) {
			pr_err("read failure at %ld (%zu of %zu read), err %d\n",
			       page * record_size, retlen, sizeof(hdr), ret);
			continue;
		}

		if (hdr.seq == 0xffffffff && hdr.magic == 0xffffffff)
			mark_page_unused(cxt, page);
		if (hdr.seq == 0xffffffff ||
		    (hdr.magic != MTDOOPS_KERNMSG_MAGIC_v1 &&
		     hdr.magic != MTDOOPS_KERNMSG_MAGIC_v2))
			continue;
		if (maxcount == 0xffffffff) {
			maxcount = hdr.seq;
			maxpos = page;
		} else if (hdr.seq < 0x40000000 && maxcount > 0xc0000000) {
			maxcount = hdr.seq;
			maxpos = page;
		} else if (hdr.seq > maxcount && hdr.seq < 0xc0000000) {
			maxcount = hdr.seq;
			maxpos = page;
		} else if (hdr.seq > maxcount && hdr.seq > 0xc0000000
					&& maxcount > 0x80000000) {
			maxcount = hdr.seq;
			maxpos = page;
		}
	}
	if (maxcount == 0xffffffff) {
		cxt->nextpage = cxt->oops_pages - 1;
		cxt->nextcount = 0;
	}
	else {
		cxt->nextpage = maxpos;
		cxt->nextcount = maxcount;
	}

	mtdoops_inc_counter(cxt, 0);
}

static void mtdoops_do_dump(struct kmsg_dumper *dumper,
			    enum kmsg_dump_reason reason)
{
	struct mtdoops_context *cxt = container_of(dumper,
			struct mtdoops_context, dump);
	struct kmsg_dump_iter iter;

	/* Only dump oopses if dump_oops is set */
	if (reason == KMSG_DUMP_OOPS && !dump_oops)
		return;

	kmsg_dump_rewind(&iter);

	if (test_and_set_bit(0, &cxt->oops_buf_busy))
		return;
	kmsg_dump_get_buffer(&iter, true,
			     cxt->oops_buf + sizeof(struct mtdoops_hdr),
			     record_size - sizeof(struct mtdoops_hdr), NULL);
	clear_bit(0, &cxt->oops_buf_busy);

	if (reason != KMSG_DUMP_OOPS) {
		/* Panics must be written immediately */
		mtdoops_write(cxt, 1);
	} else {
		/* For other cases, schedule work to write it "nicely" */
		schedule_work(&cxt->work_write);
	}
}

static void mtdoops_notify_add(struct mtd_info *mtd)
{
	struct mtdoops_context *cxt = &oops_cxt;
	u64 mtdoops_pages = div_u64(mtd->size, record_size);
	int err;

	if (!strcmp(mtd->name, mtddev))
		cxt->mtd_index = mtd->index;

	if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
		return;

	if (mtd->size < mtd->erasesize * 2) {
		pr_err("MTD partition %d not big enough for mtdoops\n",
		       mtd->index);
		return;
	}
	if (mtd->erasesize < record_size) {
		pr_err("eraseblock size of MTD partition %d too small\n",
		       mtd->index);
		return;
	}
	if (mtd->size > MTDOOPS_MAX_MTD_SIZE) {
		pr_err("mtd%d is too large (limit is %d MiB)\n",
		       mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024);
		return;
	}

	/* oops_page_used is a bit field */
	cxt->oops_page_used =
		vmalloc(array_size(sizeof(unsigned long),
				   DIV_ROUND_UP(mtdoops_pages,
						BITS_PER_LONG)));
	if (!cxt->oops_page_used) {
		pr_err("could not allocate page array\n");
		return;
	}

	cxt->dump.max_reason = KMSG_DUMP_OOPS;
	cxt->dump.dump = mtdoops_do_dump;
	err = kmsg_dump_register(&cxt->dump);
	if (err) {
		pr_err("registering kmsg dumper failed, error %d\n", err);
		vfree(cxt->oops_page_used);
		cxt->oops_page_used = NULL;
		return;
	}

	cxt->mtd = mtd;
	cxt->oops_pages = (int)mtd->size / record_size;
	find_next_position(cxt);
	pr_info("Attached to MTD device %d\n", mtd->index);
}

static void mtdoops_notify_remove(struct mtd_info *mtd)
{
	struct mtdoops_context *cxt = &oops_cxt;

	if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
		return;

	if (kmsg_dump_unregister(&cxt->dump) < 0)
		pr_warn("could not unregister kmsg_dumper\n");

	cxt->mtd = NULL;
	flush_work(&cxt->work_erase);
	flush_work(&cxt->work_write);
}


static struct mtd_notifier mtdoops_notifier = {
	.add	= mtdoops_notify_add,
	.remove	= mtdoops_notify_remove,
};

static int __init mtdoops_init(void)
{
	struct mtdoops_context *cxt = &oops_cxt;
	int mtd_index;
	char *endp;

	if (strlen(mtddev) == 0) {
		pr_err("mtd device (mtddev=name/number) must be supplied\n");
		return -EINVAL;
	}
	if ((record_size & 4095) != 0) {
		pr_err("record_size must be a multiple of 4096\n");
		return -EINVAL;
	}
	if (record_size < 4096) {
		pr_err("record_size must be over 4096 bytes\n");
		return -EINVAL;
	}

	/* Setup the MTD device to use */
	cxt->mtd_index = -1;
	mtd_index = simple_strtoul(mtddev, &endp, 0);
	if (*endp == '\0')
		cxt->mtd_index = mtd_index;

	cxt->oops_buf = vmalloc(record_size);
	if (!cxt->oops_buf)
		return -ENOMEM;
	memset(cxt->oops_buf, 0xff, record_size);
	cxt->oops_buf_busy = 0;

	INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
	INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);

	register_mtd_user(&mtdoops_notifier);
	return 0;
}

static void __exit mtdoops_exit(void)
{
	struct mtdoops_context *cxt = &oops_cxt;

	unregister_mtd_user(&mtdoops_notifier);
	vfree(cxt->oops_buf);
	vfree(cxt->oops_page_used);
}


module_init(mtdoops_init);
module_exit(mtdoops_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");
Commit	Line	Data
2b27bdcc	1	// SPDX-License-Identifier: GPL-2.0-only
4b23aff0 RP	2	/*
	3	* MTD Oops/Panic logger
	4	*
a1452a37	5	* Copyright © 2007 Nokia Corporation. All rights reserved.
4b23aff0 RP	6	*
4b23aff0 RP	7	* Author: Richard Purdie <rpurdie@openedhand.com>
4b23aff0 RP	8	*/
4b23aff0 RP	9
43cfba56 RZ	10	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
43cfba56 RZ	11
4b23aff0 RP	12	#include <linux/kernel.h>
	13	#include <linux/module.h>
	14	#include <linux/console.h>
	15	#include <linux/vmalloc.h>
	16	#include <linux/workqueue.h>
	17	#include <linux/sched.h>
	18	#include <linux/wait.h>
621e4f8e	19	#include <linux/delay.h>
f9f7dd22	20	#include <linux/interrupt.h>
aa641a22	21	#include <linux/timekeeping.h>
4b23aff0	22	#include <linux/mtd/mtd.h>
2e386e4b	23	#include <linux/kmsg_dump.h>
4b23aff0	24
1114e3d0 SK	25	/* Maximum MTD partition size */
	26	#define MTDOOPS_MAX_MTD_SIZE (8 * 1024 * 1024)
	27
9507b0c8 SK	28	static unsigned long record_size = 4096;
	29	module_param(record_size, ulong, 0400);
	30	MODULE_PARM_DESC(record_size,
	31	"record size for MTD OOPS pages in bytes (default 4096)");
4b23aff0	32
2e386e4b SK	33	static char mtddev[80];
	34	module_param_string(mtddev, mtddev, 80, 0400);
	35	MODULE_PARM_DESC(mtddev,
	36	"name or index number of the MTD device to use");
	37
	38	static int dump_oops = 1;
	39	module_param(dump_oops, int, 0600);
	40	MODULE_PARM_DESC(dump_oops,
	41	"set to 1 to dump oopses, 0 to only dump panics (default 1)");
	42
aa641a22 JME	43	#define MTDOOPS_KERNMSG_MAGIC_v1 0x5d005d00 /* Original */
aa641a22 JME	44	#define MTDOOPS_KERNMSG_MAGIC_v2 0x5d005e00 /* Adds the timestamp */
0bd359ee JME	45
	46	struct mtdoops_hdr {
	47	u32 seq;
	48	u32 magic;
aa641a22	49	ktime_t timestamp;
0bd359ee JME	50	} __packed;
0bd359ee JME	51
7903cbab	52	static struct mtdoops_context {
2e386e4b SK	53	struct kmsg_dumper dump;
2e386e4b SK	54
4b23aff0	55	int mtd_index;
6ce0a856 RP	56	struct work_struct work_erase;
6ce0a856 RP	57	struct work_struct work_write;
4b23aff0 RP	58	struct mtd_info *mtd;
	59	int oops_pages;
	60	int nextpage;
	61	int nextcount;
be95745f	62	unsigned long *oops_page_used;
4b23aff0	63
40ddbbac	64	unsigned long oops_buf_busy;
4b23aff0	65	void *oops_buf;
4b23aff0 RP	66	} oops_cxt;
4b23aff0 RP	67
be95745f SK	68	static void mark_page_used(struct mtdoops_context *cxt, int page)
	69	{
	70	set_bit(page, cxt->oops_page_used);
	71	}
	72
	73	static void mark_page_unused(struct mtdoops_context *cxt, int page)
	74	{
	75	clear_bit(page, cxt->oops_page_used);
	76	}
	77
	78	static int page_is_used(struct mtdoops_context *cxt, int page)
	79	{
	80	return test_bit(page, cxt->oops_page_used);
	81	}
	82
be95745f	83	static int mtdoops_erase_block(struct mtdoops_context *cxt, int offset)
4b23aff0	84	{
be95745f SK	85	struct mtd_info *mtd = cxt->mtd;
be95745f SK	86	u32 start_page_offset = mtd_div_by_eb(offset, mtd) * mtd->erasesize;
9507b0c8 SK	87	u32 start_page = start_page_offset / record_size;
9507b0c8 SK	88	u32 erase_pages = mtd->erasesize / record_size;
4b23aff0	89	struct erase_info erase;
4b23aff0	90	int ret;
be95745f	91	int page;
4b23aff0	92
4b23aff0	93	erase.addr = offset;
79dcd8e9	94	erase.len = mtd->erasesize;
4b23aff0	95
7e1f0dc0	96	ret = mtd_erase(mtd, &erase);
4b23aff0	97	if (ret) {
43cfba56 RZ	98	pr_warn("erase of region [0x%llx, 0x%llx] on \"%s\" failed\n",
	99	(unsigned long long)erase.addr,
	100	(unsigned long long)erase.len, mtddev);
4b23aff0 RP	101	return ret;
	102	}
	103
be95745f SK	104	/* Mark pages as unused */
	105	for (page = start_page; page < start_page + erase_pages; page++)
	106	mark_page_unused(cxt, page);
	107
4b23aff0 RP	108	return 0;
	109	}
	110
340193e0	111	static void mtdoops_erase(struct mtdoops_context *cxt)
4b23aff0 RP	112	{
	113	struct mtd_info *mtd = cxt->mtd;
	114	int i = 0, j, ret, mod;
	115
	116	/* We were unregistered */
	117	if (!mtd)
	118	return;
	119
9507b0c8	120	mod = (cxt->nextpage * record_size) % mtd->erasesize;
4b23aff0	121	if (mod != 0) {
9507b0c8	122	cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / record_size);
ecd5b310	123	if (cxt->nextpage >= cxt->oops_pages)
4b23aff0 RP	124	cxt->nextpage = 0;
	125	}
	126
9cb93fbb	127	while ((ret = mtd_block_isbad(mtd, cxt->nextpage * record_size)) > 0) {
4b23aff0	128	badblock:
43cfba56 RZ	129	pr_warn("bad block at %08lx\n",
43cfba56 RZ	130	cxt->nextpage * record_size);
4b23aff0	131	i++;
9507b0c8	132	cxt->nextpage = cxt->nextpage + (mtd->erasesize / record_size);
ecd5b310	133	if (cxt->nextpage >= cxt->oops_pages)
4b23aff0	134	cxt->nextpage = 0;
9507b0c8	135	if (i == cxt->oops_pages / (mtd->erasesize / record_size)) {
43cfba56	136	pr_err("all blocks bad!\n");
4b23aff0 RP	137	return;
	138	}
	139	}
	140
9cb93fbb	141	if (ret < 0) {
43cfba56	142	pr_err("mtd_block_isbad failed, aborting\n");
9cb93fbb BN	143	return;
	144	}
	145
4b23aff0	146	for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
9507b0c8	147	ret = mtdoops_erase_block(cxt, cxt->nextpage * record_size);
4b23aff0	148
2986bd2a	149	if (ret >= 0) {
43cfba56 RZ	150	pr_debug("ready %d, %d\n",
43cfba56 RZ	151	cxt->nextpage, cxt->nextcount);
2986bd2a	152	return;
4b23aff0 RP	153	}
4b23aff0 RP	154
bb4a0986	155	if (ret == -EIO) {
5942ddbc	156	ret = mtd_block_markbad(mtd, cxt->nextpage * record_size);
bb4a0986	157	if (ret < 0 && ret != -EOPNOTSUPP) {
43cfba56	158	pr_err("block_markbad failed, aborting\n");
2986bd2a RP	159	return;
	160	}
	161	}
	162	goto badblock;
4b23aff0 RP	163	}
4b23aff0 RP	164
340193e0 RZ	165	/* Scheduled work - when we can't proceed without erasing a block */
	166	static void mtdoops_workfunc_erase(struct work_struct *work)
	167	{
	168	struct mtdoops_context *cxt =
	169	container_of(work, struct mtdoops_context, work_erase);
	170	mtdoops_erase(cxt);
	171	}
	172
7cc84e0e	173	static void mtdoops_inc_counter(struct mtdoops_context *cxt, int panic)
340193e0 RZ	174	{
	175	cxt->nextpage++;
	176	if (cxt->nextpage >= cxt->oops_pages)
	177	cxt->nextpage = 0;
	178	cxt->nextcount++;
	179	if (cxt->nextcount == 0xffffffff)
	180	cxt->nextcount = 0;
	181
	182	if (page_is_used(cxt, cxt->nextpage)) {
7cc84e0e RZ	183	pr_debug("not ready %d, %d (erase %s)\n",
	184	cxt->nextpage, cxt->nextcount,
	185	panic ? "immediately" : "scheduled");
	186	if (panic) {
	187	/* In case of panic, erase immediately */
	188	mtdoops_erase(cxt);
	189	} else {
	190	/* Otherwise, schedule work to erase it "nicely" */
	191	schedule_work(&cxt->work_erase);
	192	}
	193	} else {
	194	pr_debug("ready %d, %d (no erase)\n",
	195	cxt->nextpage, cxt->nextcount);
340193e0	196	}
340193e0 RZ	197	}
340193e0 RZ	198
621e4f8e	199	static void mtdoops_write(struct mtdoops_context *cxt, int panic)
4b23aff0	200	{
6ce0a856 RP	201	struct mtd_info *mtd = cxt->mtd;
6ce0a856 RP	202	size_t retlen;
0bd359ee	203	struct mtdoops_hdr *hdr;
6ce0a856	204	int ret;
4b23aff0	205
40ddbbac JO	206	if (test_and_set_bit(0, &cxt->oops_buf_busy))
	207	return;
	208
2e386e4b	209	/* Add mtdoops header to the buffer */
0bd359ee JME	210	hdr = (struct mtdoops_hdr *)cxt->oops_buf;
0bd359ee JME	211	hdr->seq = cxt->nextcount;
aa641a22 JME	212	hdr->magic = MTDOOPS_KERNMSG_MAGIC_v2;
aa641a22 JME	213	hdr->timestamp = ktime_get_real();
6ce0a856	214
016c1291	215	if (panic) {
7ae79d7f AB	216	ret = mtd_panic_write(mtd, cxt->nextpage * record_size,
7ae79d7f AB	217	record_size, &retlen, cxt->oops_buf);
016c1291	218	if (ret == -EOPNOTSUPP) {
43cfba56	219	pr_err("Cannot write from panic without panic_write\n");
40ddbbac	220	goto out;
016c1291 AB	221	}
016c1291 AB	222	} else
eda95cbf AB	223	ret = mtd_write(mtd, cxt->nextpage * record_size,
eda95cbf AB	224	record_size, &retlen, cxt->oops_buf);
6ce0a856	225
9507b0c8	226	if (retlen != record_size \|\| ret < 0)
43cfba56	227	pr_err("write failure at %ld (%td of %ld written), error %d\n",
9507b0c8	228	cxt->nextpage * record_size, retlen, record_size, ret);
be95745f	229	mark_page_used(cxt, cxt->nextpage);
2e386e4b	230	memset(cxt->oops_buf, 0xff, record_size);
6ce0a856	231
7cc84e0e	232	mtdoops_inc_counter(cxt, panic);
40ddbbac JO	233	out:
40ddbbac JO	234	clear_bit(0, &cxt->oops_buf_busy);
621e4f8e RP	235	}
621e4f8e RP	236
621e4f8e RP	237	static void mtdoops_workfunc_write(struct work_struct *work)
	238	{
	239	struct mtdoops_context *cxt =
	240	container_of(work, struct mtdoops_context, work_write);
	241
	242	mtdoops_write(cxt, 0);
a15b124f	243	}
4b23aff0	244
6ce0a856	245	static void find_next_position(struct mtdoops_context *cxt)
4b23aff0 RP	246	{
4b23aff0 RP	247	struct mtd_info *mtd = cxt->mtd;
0bd359ee	248	struct mtdoops_hdr hdr;
2986bd2a	249	int ret, page, maxpos = 0;
0bd359ee	250	u32 maxcount = 0xffffffff;
4b23aff0 RP	251	size_t retlen;
	252
	253	for (page = 0; page < cxt->oops_pages; page++) {
bb4a0986	254	if (mtd_block_isbad(mtd, page * record_size))
3538c563	255	continue;
be95745f SK	256	/* Assume the page is used */
be95745f SK	257	mark_page_used(cxt, page);
0bd359ee JME	258	ret = mtd_read(mtd, page * record_size, sizeof(hdr),
	259	&retlen, (u_char *)&hdr);
	260	if (retlen != sizeof(hdr) \|\|
d57f4054	261	(ret < 0 && !mtd_is_bitflip(ret))) {
43cfba56	262	pr_err("read failure at %ld (%zu of %zu read), err %d\n",
0bd359ee	263	page * record_size, retlen, sizeof(hdr), ret);
2986bd2a RP	264	continue;
	265	}
	266
0bd359ee	267	if (hdr.seq == 0xffffffff && hdr.magic == 0xffffffff)
be95745f	268	mark_page_unused(cxt, page);
aa641a22 JME	269	if (hdr.seq == 0xffffffff \|\|
	270	(hdr.magic != MTDOOPS_KERNMSG_MAGIC_v1 &&
	271	hdr.magic != MTDOOPS_KERNMSG_MAGIC_v2))
4b23aff0 RP	272	continue;
4b23aff0 RP	273	if (maxcount == 0xffffffff) {
0bd359ee	274	maxcount = hdr.seq;
4b23aff0	275	maxpos = page;
0bd359ee JME	276	} else if (hdr.seq < 0x40000000 && maxcount > 0xc0000000) {
0bd359ee JME	277	maxcount = hdr.seq;
4b23aff0	278	maxpos = page;
0bd359ee JME	279	} else if (hdr.seq > maxcount && hdr.seq < 0xc0000000) {
0bd359ee JME	280	maxcount = hdr.seq;
4b23aff0	281	maxpos = page;
0bd359ee	282	} else if (hdr.seq > maxcount && hdr.seq > 0xc0000000
a15b124f	283	&& maxcount > 0x80000000) {
0bd359ee	284	maxcount = hdr.seq;
4b23aff0 RP	285	maxpos = page;
	286	}
	287	}
	288	if (maxcount == 0xffffffff) {
cd409c61 MC	289	cxt->nextpage = cxt->oops_pages - 1;
	290	cxt->nextcount = 0;
	291	}
	292	else {
	293	cxt->nextpage = maxpos;
	294	cxt->nextcount = maxcount;
4b23aff0	295	}
4b23aff0	296
7cc84e0e	297	mtdoops_inc_counter(cxt, 0);
4b23aff0 RP	298	}
4b23aff0 RP	299
2e386e4b	300	static void mtdoops_do_dump(struct kmsg_dumper *dumper,
e2ae715d	301	enum kmsg_dump_reason reason)
2e386e4b SK	302	{
	303	struct mtdoops_context *cxt = container_of(dumper,
	304	struct mtdoops_context, dump);
f9f3f02d	305	struct kmsg_dump_iter iter;
fc2d557c	306
2e386e4b SK	307	/* Only dump oopses if dump_oops is set */
	308	if (reason == KMSG_DUMP_OOPS && !dump_oops)
	309	return;
	310
f9f3f02d JO	311	kmsg_dump_rewind(&iter);
f9f3f02d JO	312
40ddbbac JO	313	if (test_and_set_bit(0, &cxt->oops_buf_busy))
40ddbbac JO	314	return;
0bd359ee JME	315	kmsg_dump_get_buffer(&iter, true,
	316	cxt->oops_buf + sizeof(struct mtdoops_hdr),
	317	record_size - sizeof(struct mtdoops_hdr), NULL);
40ddbbac	318	clear_bit(0, &cxt->oops_buf_busy);
2e386e4b	319
c1cf1d57 MT	320	if (reason != KMSG_DUMP_OOPS) {
c1cf1d57 MT	321	/* Panics must be written immediately */
016c1291	322	mtdoops_write(cxt, 1);
c1cf1d57 MT	323	} else {
	324	/* For other cases, schedule work to write it "nicely" */
	325	schedule_work(&cxt->work_write);
	326	}
2e386e4b	327	}
4b23aff0 RP	328
	329	static void mtdoops_notify_add(struct mtd_info *mtd)
	330	{
	331	struct mtdoops_context *cxt = &oops_cxt;
2e386e4b SK	332	u64 mtdoops_pages = div_u64(mtd->size, record_size);
2e386e4b SK	333	int err;
4b23aff0	334
2e386e4b	335	if (!strcmp(mtd->name, mtddev))
e2a0f25b AH	336	cxt->mtd_index = mtd->index;
e2a0f25b AH	337
a15b124f	338	if (mtd->index != cxt->mtd_index \|\| cxt->mtd_index < 0)
4b23aff0 RP	339	return;
4b23aff0 RP	340
a15b124f	341	if (mtd->size < mtd->erasesize * 2) {
43cfba56	342	pr_err("MTD partition %d not big enough for mtdoops\n",
a15b124f	343	mtd->index);
4b23aff0 RP	344	return;
4b23aff0 RP	345	}
9507b0c8	346	if (mtd->erasesize < record_size) {
43cfba56	347	pr_err("eraseblock size of MTD partition %d too small\n",
a15b124f	348	mtd->index);
79dcd8e9 RP	349	return;
79dcd8e9 RP	350	}
1114e3d0	351	if (mtd->size > MTDOOPS_MAX_MTD_SIZE) {
43cfba56	352	pr_err("mtd%d is too large (limit is %d MiB)\n",
1114e3d0 SK	353	mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024);
	354	return;
	355	}
	356
be95745f	357	/* oops_page_used is a bit field */
42bc47b3 KC	358	cxt->oops_page_used =
	359	vmalloc(array_size(sizeof(unsigned long),
	360	DIV_ROUND_UP(mtdoops_pages,
	361	BITS_PER_LONG)));
be95745f	362	if (!cxt->oops_page_used) {
43cfba56	363	pr_err("could not allocate page array\n");
2e386e4b SK	364	return;
	365	}
	366
e2ae715d	367	cxt->dump.max_reason = KMSG_DUMP_OOPS;
2e386e4b SK	368	cxt->dump.dump = mtdoops_do_dump;
	369	err = kmsg_dump_register(&cxt->dump);
	370	if (err) {
43cfba56	371	pr_err("registering kmsg dumper failed, error %d\n", err);
2e386e4b SK	372	vfree(cxt->oops_page_used);
2e386e4b SK	373	cxt->oops_page_used = NULL;
be95745f SK	374	return;
be95745f SK	375	}
4b23aff0	376
1114e3d0	377	cxt->mtd = mtd;
9507b0c8	378	cxt->oops_pages = (int)mtd->size / record_size;
6ce0a856	379	find_next_position(cxt);
43cfba56	380	pr_info("Attached to MTD device %d\n", mtd->index);
4b23aff0 RP	381	}
	382
	383	static void mtdoops_notify_remove(struct mtd_info *mtd)
	384	{
	385	struct mtdoops_context *cxt = &oops_cxt;
	386
a15b124f	387	if (mtd->index != cxt->mtd_index \|\| cxt->mtd_index < 0)
4b23aff0 RP	388	return;
4b23aff0 RP	389
2e386e4b	390	if (kmsg_dump_unregister(&cxt->dump) < 0)
43cfba56	391	pr_warn("could not unregister kmsg_dumper\n");
2e386e4b	392
4b23aff0	393	cxt->mtd = NULL;
43829731 TH	394	flush_work(&cxt->work_erase);
43829731 TH	395	flush_work(&cxt->work_write);
4b23aff0 RP	396	}
4b23aff0 RP	397
4b23aff0 RP	398
	399	static struct mtd_notifier mtdoops_notifier = {
	400	.add = mtdoops_notify_add,
	401	.remove = mtdoops_notify_remove,
	402	};
	403
2e386e4b	404	static int __init mtdoops_init(void)
4b23aff0 RP	405	{
4b23aff0 RP	406	struct mtdoops_context *cxt = &oops_cxt;
2e386e4b SK	407	int mtd_index;
2e386e4b SK	408	char *endp;
4b23aff0	409
2e386e4b	410	if (strlen(mtddev) == 0) {
43cfba56	411	pr_err("mtd device (mtddev=name/number) must be supplied\n");
2e386e4b SK	412	return -EINVAL;
2e386e4b SK	413	}
9507b0c8	414	if ((record_size & 4095) != 0) {
43cfba56	415	pr_err("record_size must be a multiple of 4096\n");
9507b0c8 SK	416	return -EINVAL;
	417	}
	418	if (record_size < 4096) {
43cfba56	419	pr_err("record_size must be over 4096 bytes\n");
9507b0c8 SK	420	return -EINVAL;
9507b0c8 SK	421	}
2e386e4b SK	422
2e386e4b SK	423	/* Setup the MTD device to use */
4b23aff0	424	cxt->mtd_index = -1;
2e386e4b SK	425	mtd_index = simple_strtoul(mtddev, &endp, 0);
	426	if (*endp == '\0')
	427	cxt->mtd_index = mtd_index;
2e386e4b	428
9507b0c8	429	cxt->oops_buf = vmalloc(record_size);
313ea21a	430	if (!cxt->oops_buf)
4b23aff0	431	return -ENOMEM;
2e386e4b	432	memset(cxt->oops_buf, 0xff, record_size);
40ddbbac	433	cxt->oops_buf_busy = 0;
4b23aff0	434
6ce0a856 RP	435	INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
6ce0a856 RP	436	INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
4b23aff0	437
4b23aff0 RP	438	register_mtd_user(&mtdoops_notifier);
	439	return 0;
	440	}
	441
2e386e4b	442	static void __exit mtdoops_exit(void)
4b23aff0 RP	443	{
	444	struct mtdoops_context *cxt = &oops_cxt;
	445
	446	unregister_mtd_user(&mtdoops_notifier);
4b23aff0	447	vfree(cxt->oops_buf);
be95745f	448	vfree(cxt->oops_page_used);
4b23aff0 RP	449	}
	450
	451
2e386e4b SK	452	module_init(mtdoops_init);
2e386e4b SK	453	module_exit(mtdoops_exit);
4b23aff0 RP	454
	455	MODULE_LICENSE("GPL");
	456	MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
	457	MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");