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431 lines
11 KiB
431 lines
11 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* MTD Oops/Panic logger |
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* |
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* Copyright © 2007 Nokia Corporation. All rights reserved. |
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* |
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* Author: Richard Purdie <[email protected]> |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/console.h> |
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#include <linux/vmalloc.h> |
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#include <linux/workqueue.h> |
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#include <linux/sched.h> |
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#include <linux/wait.h> |
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#include <linux/delay.h> |
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#include <linux/interrupt.h> |
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#include <linux/mtd/mtd.h> |
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#include <linux/kmsg_dump.h> |
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/* Maximum MTD partition size */ |
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#define MTDOOPS_MAX_MTD_SIZE (8 * 1024 * 1024) |
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#define MTDOOPS_KERNMSG_MAGIC 0x5d005d00 |
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#define MTDOOPS_HEADER_SIZE 8 |
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static unsigned long record_size = 4096; |
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module_param(record_size, ulong, 0400); |
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MODULE_PARM_DESC(record_size, |
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"record size for MTD OOPS pages in bytes (default 4096)"); |
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static char mtddev[80]; |
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module_param_string(mtddev, mtddev, 80, 0400); |
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MODULE_PARM_DESC(mtddev, |
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"name or index number of the MTD device to use"); |
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static int dump_oops = 1; |
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module_param(dump_oops, int, 0600); |
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MODULE_PARM_DESC(dump_oops, |
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"set to 1 to dump oopses, 0 to only dump panics (default 1)"); |
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static struct mtdoops_context { |
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struct kmsg_dumper dump; |
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int mtd_index; |
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struct work_struct work_erase; |
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struct work_struct work_write; |
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struct mtd_info *mtd; |
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int oops_pages; |
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int nextpage; |
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int nextcount; |
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unsigned long *oops_page_used; |
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unsigned long oops_buf_busy; |
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void *oops_buf; |
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} oops_cxt; |
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static void mark_page_used(struct mtdoops_context *cxt, int page) |
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{ |
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set_bit(page, cxt->oops_page_used); |
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} |
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static void mark_page_unused(struct mtdoops_context *cxt, int page) |
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{ |
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clear_bit(page, cxt->oops_page_used); |
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} |
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static int page_is_used(struct mtdoops_context *cxt, int page) |
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{ |
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return test_bit(page, cxt->oops_page_used); |
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} |
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static int mtdoops_erase_block(struct mtdoops_context *cxt, int offset) |
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{ |
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struct mtd_info *mtd = cxt->mtd; |
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u32 start_page_offset = mtd_div_by_eb(offset, mtd) * mtd->erasesize; |
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u32 start_page = start_page_offset / record_size; |
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u32 erase_pages = mtd->erasesize / record_size; |
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struct erase_info erase; |
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int ret; |
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int page; |
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erase.addr = offset; |
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erase.len = mtd->erasesize; |
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ret = mtd_erase(mtd, &erase); |
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if (ret) { |
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printk(KERN_WARNING "mtdoops: erase of region [0x%llx, 0x%llx] on \"%s\" failed\n", |
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(unsigned long long)erase.addr, |
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(unsigned long long)erase.len, mtddev); |
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return ret; |
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} |
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/* Mark pages as unused */ |
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for (page = start_page; page < start_page + erase_pages; page++) |
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mark_page_unused(cxt, page); |
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return 0; |
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} |
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static void mtdoops_inc_counter(struct mtdoops_context *cxt) |
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{ |
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cxt->nextpage++; |
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if (cxt->nextpage >= cxt->oops_pages) |
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cxt->nextpage = 0; |
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cxt->nextcount++; |
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if (cxt->nextcount == 0xffffffff) |
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cxt->nextcount = 0; |
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if (page_is_used(cxt, cxt->nextpage)) { |
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schedule_work(&cxt->work_erase); |
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return; |
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} |
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printk(KERN_DEBUG "mtdoops: ready %d, %d (no erase)\n", |
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cxt->nextpage, cxt->nextcount); |
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} |
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/* Scheduled work - when we can't proceed without erasing a block */ |
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static void mtdoops_workfunc_erase(struct work_struct *work) |
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{ |
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struct mtdoops_context *cxt = |
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container_of(work, struct mtdoops_context, work_erase); |
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struct mtd_info *mtd = cxt->mtd; |
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int i = 0, j, ret, mod; |
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/* We were unregistered */ |
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if (!mtd) |
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return; |
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mod = (cxt->nextpage * record_size) % mtd->erasesize; |
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if (mod != 0) { |
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cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / record_size); |
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if (cxt->nextpage >= cxt->oops_pages) |
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cxt->nextpage = 0; |
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} |
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while ((ret = mtd_block_isbad(mtd, cxt->nextpage * record_size)) > 0) { |
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badblock: |
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printk(KERN_WARNING "mtdoops: bad block at %08lx\n", |
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cxt->nextpage * record_size); |
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i++; |
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cxt->nextpage = cxt->nextpage + (mtd->erasesize / record_size); |
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if (cxt->nextpage >= cxt->oops_pages) |
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cxt->nextpage = 0; |
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if (i == cxt->oops_pages / (mtd->erasesize / record_size)) { |
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printk(KERN_ERR "mtdoops: all blocks bad!\n"); |
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return; |
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} |
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} |
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if (ret < 0) { |
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printk(KERN_ERR "mtdoops: mtd_block_isbad failed, aborting\n"); |
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return; |
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} |
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for (j = 0, ret = -1; (j < 3) && (ret < 0); j++) |
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ret = mtdoops_erase_block(cxt, cxt->nextpage * record_size); |
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if (ret >= 0) { |
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printk(KERN_DEBUG "mtdoops: ready %d, %d\n", |
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cxt->nextpage, cxt->nextcount); |
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return; |
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} |
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if (ret == -EIO) { |
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ret = mtd_block_markbad(mtd, cxt->nextpage * record_size); |
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if (ret < 0 && ret != -EOPNOTSUPP) { |
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printk(KERN_ERR "mtdoops: block_markbad failed, aborting\n"); |
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return; |
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} |
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} |
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goto badblock; |
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} |
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static void mtdoops_write(struct mtdoops_context *cxt, int panic) |
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{ |
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struct mtd_info *mtd = cxt->mtd; |
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size_t retlen; |
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u32 *hdr; |
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int ret; |
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if (test_and_set_bit(0, &cxt->oops_buf_busy)) |
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return; |
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/* Add mtdoops header to the buffer */ |
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hdr = cxt->oops_buf; |
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hdr[0] = cxt->nextcount; |
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hdr[1] = MTDOOPS_KERNMSG_MAGIC; |
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if (panic) { |
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ret = mtd_panic_write(mtd, cxt->nextpage * record_size, |
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record_size, &retlen, cxt->oops_buf); |
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if (ret == -EOPNOTSUPP) { |
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printk(KERN_ERR "mtdoops: Cannot write from panic without panic_write\n"); |
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goto out; |
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} |
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} else |
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ret = mtd_write(mtd, cxt->nextpage * record_size, |
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record_size, &retlen, cxt->oops_buf); |
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if (retlen != record_size || ret < 0) |
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printk(KERN_ERR "mtdoops: write failure at %ld (%td of %ld written), error %d\n", |
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cxt->nextpage * record_size, retlen, record_size, ret); |
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mark_page_used(cxt, cxt->nextpage); |
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memset(cxt->oops_buf, 0xff, record_size); |
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mtdoops_inc_counter(cxt); |
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out: |
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clear_bit(0, &cxt->oops_buf_busy); |
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} |
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static void mtdoops_workfunc_write(struct work_struct *work) |
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{ |
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struct mtdoops_context *cxt = |
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container_of(work, struct mtdoops_context, work_write); |
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mtdoops_write(cxt, 0); |
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} |
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static void find_next_position(struct mtdoops_context *cxt) |
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{ |
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struct mtd_info *mtd = cxt->mtd; |
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int ret, page, maxpos = 0; |
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u32 count[2], maxcount = 0xffffffff; |
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size_t retlen; |
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for (page = 0; page < cxt->oops_pages; page++) { |
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if (mtd_block_isbad(mtd, page * record_size)) |
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continue; |
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/* Assume the page is used */ |
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mark_page_used(cxt, page); |
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ret = mtd_read(mtd, page * record_size, MTDOOPS_HEADER_SIZE, |
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&retlen, (u_char *)&count[0]); |
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if (retlen != MTDOOPS_HEADER_SIZE || |
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(ret < 0 && !mtd_is_bitflip(ret))) { |
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printk(KERN_ERR "mtdoops: read failure at %ld (%td of %d read), err %d\n", |
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page * record_size, retlen, |
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MTDOOPS_HEADER_SIZE, ret); |
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continue; |
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} |
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if (count[0] == 0xffffffff && count[1] == 0xffffffff) |
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mark_page_unused(cxt, page); |
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if (count[0] == 0xffffffff || count[1] != MTDOOPS_KERNMSG_MAGIC) |
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continue; |
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if (maxcount == 0xffffffff) { |
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maxcount = count[0]; |
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maxpos = page; |
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} else if (count[0] < 0x40000000 && maxcount > 0xc0000000) { |
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maxcount = count[0]; |
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maxpos = page; |
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} else if (count[0] > maxcount && count[0] < 0xc0000000) { |
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maxcount = count[0]; |
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maxpos = page; |
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} else if (count[0] > maxcount && count[0] > 0xc0000000 |
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&& maxcount > 0x80000000) { |
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maxcount = count[0]; |
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maxpos = page; |
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} |
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} |
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if (maxcount == 0xffffffff) { |
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cxt->nextpage = cxt->oops_pages - 1; |
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cxt->nextcount = 0; |
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} |
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else { |
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cxt->nextpage = maxpos; |
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cxt->nextcount = maxcount; |
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} |
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mtdoops_inc_counter(cxt); |
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} |
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static void mtdoops_do_dump(struct kmsg_dumper *dumper, |
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enum kmsg_dump_reason reason) |
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{ |
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struct mtdoops_context *cxt = container_of(dumper, |
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struct mtdoops_context, dump); |
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struct kmsg_dump_iter iter; |
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/* Only dump oopses if dump_oops is set */ |
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if (reason == KMSG_DUMP_OOPS && !dump_oops) |
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return; |
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kmsg_dump_rewind(&iter); |
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if (test_and_set_bit(0, &cxt->oops_buf_busy)) |
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return; |
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kmsg_dump_get_buffer(&iter, true, cxt->oops_buf + MTDOOPS_HEADER_SIZE, |
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record_size - MTDOOPS_HEADER_SIZE, NULL); |
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clear_bit(0, &cxt->oops_buf_busy); |
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if (reason != KMSG_DUMP_OOPS) { |
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/* Panics must be written immediately */ |
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mtdoops_write(cxt, 1); |
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} else { |
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/* For other cases, schedule work to write it "nicely" */ |
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schedule_work(&cxt->work_write); |
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} |
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} |
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static void mtdoops_notify_add(struct mtd_info *mtd) |
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{ |
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struct mtdoops_context *cxt = &oops_cxt; |
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u64 mtdoops_pages = div_u64(mtd->size, record_size); |
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int err; |
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if (!strcmp(mtd->name, mtddev)) |
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cxt->mtd_index = mtd->index; |
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if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0) |
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return; |
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if (mtd->size < mtd->erasesize * 2) { |
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printk(KERN_ERR "mtdoops: MTD partition %d not big enough for mtdoops\n", |
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mtd->index); |
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return; |
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} |
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if (mtd->erasesize < record_size) { |
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printk(KERN_ERR "mtdoops: eraseblock size of MTD partition %d too small\n", |
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mtd->index); |
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return; |
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} |
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if (mtd->size > MTDOOPS_MAX_MTD_SIZE) { |
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printk(KERN_ERR "mtdoops: mtd%d is too large (limit is %d MiB)\n", |
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mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024); |
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return; |
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} |
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/* oops_page_used is a bit field */ |
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cxt->oops_page_used = |
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vmalloc(array_size(sizeof(unsigned long), |
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DIV_ROUND_UP(mtdoops_pages, |
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BITS_PER_LONG))); |
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if (!cxt->oops_page_used) { |
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printk(KERN_ERR "mtdoops: could not allocate page array\n"); |
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return; |
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} |
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cxt->dump.max_reason = KMSG_DUMP_OOPS; |
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cxt->dump.dump = mtdoops_do_dump; |
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err = kmsg_dump_register(&cxt->dump); |
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if (err) { |
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printk(KERN_ERR "mtdoops: registering kmsg dumper failed, error %d\n", err); |
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vfree(cxt->oops_page_used); |
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cxt->oops_page_used = NULL; |
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return; |
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} |
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cxt->mtd = mtd; |
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cxt->oops_pages = (int)mtd->size / record_size; |
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find_next_position(cxt); |
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printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index); |
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} |
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static void mtdoops_notify_remove(struct mtd_info *mtd) |
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{ |
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struct mtdoops_context *cxt = &oops_cxt; |
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if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0) |
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return; |
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if (kmsg_dump_unregister(&cxt->dump) < 0) |
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printk(KERN_WARNING "mtdoops: could not unregister kmsg_dumper\n"); |
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cxt->mtd = NULL; |
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flush_work(&cxt->work_erase); |
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flush_work(&cxt->work_write); |
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} |
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static struct mtd_notifier mtdoops_notifier = { |
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.add = mtdoops_notify_add, |
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.remove = mtdoops_notify_remove, |
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}; |
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static int __init mtdoops_init(void) |
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{ |
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struct mtdoops_context *cxt = &oops_cxt; |
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int mtd_index; |
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char *endp; |
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if (strlen(mtddev) == 0) { |
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printk(KERN_ERR "mtdoops: mtd device (mtddev=name/number) must be supplied\n"); |
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return -EINVAL; |
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} |
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if ((record_size & 4095) != 0) { |
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printk(KERN_ERR "mtdoops: record_size must be a multiple of 4096\n"); |
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return -EINVAL; |
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} |
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if (record_size < 4096) { |
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printk(KERN_ERR "mtdoops: record_size must be over 4096 bytes\n"); |
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return -EINVAL; |
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} |
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/* Setup the MTD device to use */ |
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cxt->mtd_index = -1; |
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mtd_index = simple_strtoul(mtddev, &endp, 0); |
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if (*endp == '\0') |
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cxt->mtd_index = mtd_index; |
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cxt->oops_buf = vmalloc(record_size); |
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if (!cxt->oops_buf) |
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return -ENOMEM; |
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memset(cxt->oops_buf, 0xff, record_size); |
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cxt->oops_buf_busy = 0; |
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INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase); |
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INIT_WORK(&cxt->work_write, mtdoops_workfunc_write); |
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register_mtd_user(&mtdoops_notifier); |
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return 0; |
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} |
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static void __exit mtdoops_exit(void) |
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{ |
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struct mtdoops_context *cxt = &oops_cxt; |
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unregister_mtd_user(&mtdoops_notifier); |
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vfree(cxt->oops_buf); |
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vfree(cxt->oops_page_used); |
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} |
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module_init(mtdoops_init); |
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module_exit(mtdoops_exit); |
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MODULE_LICENSE("GPL"); |
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MODULE_AUTHOR("Richard Purdie <[email protected]>"); |
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MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");
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