// 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,			    struct kmsg_dump_detail *detail){	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 (detail->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 (detail->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(DIV_ROUND_UP(mtdoops_pages, BITS_PER_LONG),			      sizeof(unsigned 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);	vfree(cxt->oops_page_used);	cxt->oops_page_used = NULL;	cxt->oops_pages = 0;}  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;	unsigned int mtd_index; 	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;	if (kstrtouint(mtddev, 0, &mtd_index) == 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");