1 files changed, 457 insertions, 0 deletions

diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c
new file mode 100644
index 000000000..2f11585b5
--- /dev/null
+++ b/drivers/mtd/mtdoops.c
@@ -0,0 +1,457 @@
+// 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");