diff options
Diffstat (limited to 'drivers/mtd/mtdoops.c')
| -rw-r--r-- | drivers/mtd/mtdoops.c | 420 |
1 files changed, 420 insertions, 0 deletions
diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c new file mode 100644 index 000000000..774970bfc --- /dev/null +++ b/drivers/mtd/mtdoops.c @@ -0,0 +1,420 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * MTD Oops/Panic logger + * + * Copyright © 2007 Nokia Corporation. All rights reserved. + * + * Author: Richard Purdie <rpurdie@openedhand.com> + */ + +#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/mtd/mtd.h> +#include <linux/kmsg_dump.h> + +/* Maximum MTD partition size */ +#define MTDOOPS_MAX_MTD_SIZE (8 * 1024 * 1024) + +#define MTDOOPS_KERNMSG_MAGIC 0x5d005d00 +#define MTDOOPS_HEADER_SIZE 8 + +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)"); + +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; + + 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) { + printk(KERN_WARNING "mtdoops: 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_inc_counter(struct mtdoops_context *cxt) +{ + 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)) { + schedule_work(&cxt->work_erase); + return; + } + + printk(KERN_DEBUG "mtdoops: ready %d, %d (no erase)\n", + cxt->nextpage, cxt->nextcount); +} + +/* 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); + 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: + printk(KERN_WARNING "mtdoops: 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)) { + printk(KERN_ERR "mtdoops: all blocks bad!\n"); + return; + } + } + + if (ret < 0) { + printk(KERN_ERR "mtdoops: 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) { + printk(KERN_DEBUG "mtdoops: 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) { + printk(KERN_ERR "mtdoops: block_markbad failed, aborting\n"); + return; + } + } + goto badblock; +} + +static void mtdoops_write(struct mtdoops_context *cxt, int panic) +{ + struct mtd_info *mtd = cxt->mtd; + size_t retlen; + u32 *hdr; + int ret; + + /* Add mtdoops header to the buffer */ + hdr = cxt->oops_buf; + hdr[0] = cxt->nextcount; + hdr[1] = MTDOOPS_KERNMSG_MAGIC; + + if (panic) { + ret = mtd_panic_write(mtd, cxt->nextpage * record_size, + record_size, &retlen, cxt->oops_buf); + if (ret == -EOPNOTSUPP) { + printk(KERN_ERR "mtdoops: Cannot write from panic without panic_write\n"); + return; + } + } else + ret = mtd_write(mtd, cxt->nextpage * record_size, + record_size, &retlen, cxt->oops_buf); + + if (retlen != record_size || ret < 0) + printk(KERN_ERR "mtdoops: 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); +} + +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; + int ret, page, maxpos = 0; + u32 count[2], 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, MTDOOPS_HEADER_SIZE, + &retlen, (u_char *)&count[0]); + if (retlen != MTDOOPS_HEADER_SIZE || + (ret < 0 && !mtd_is_bitflip(ret))) { + printk(KERN_ERR "mtdoops: read failure at %ld (%td of %d read), err %d\n", + page * record_size, retlen, + MTDOOPS_HEADER_SIZE, ret); + continue; + } + + if (count[0] == 0xffffffff && count[1] == 0xffffffff) + mark_page_unused(cxt, page); + if (count[0] == 0xffffffff || count[1] != MTDOOPS_KERNMSG_MAGIC) + continue; + if (maxcount == 0xffffffff) { + maxcount = count[0]; + maxpos = page; + } else if (count[0] < 0x40000000 && maxcount > 0xc0000000) { + maxcount = count[0]; + maxpos = page; + } else if (count[0] > maxcount && count[0] < 0xc0000000) { + maxcount = count[0]; + maxpos = page; + } else if (count[0] > maxcount && count[0] > 0xc0000000 + && maxcount > 0x80000000) { + maxcount = count[0]; + 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); +} + +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); + + /* Only dump oopses if dump_oops is set */ + if (reason == KMSG_DUMP_OOPS && !dump_oops) + return; + + kmsg_dump_get_buffer(dumper, true, cxt->oops_buf + MTDOOPS_HEADER_SIZE, + record_size - MTDOOPS_HEADER_SIZE, NULL); + + 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) { + printk(KERN_ERR "mtdoops: MTD partition %d not big enough for mtdoops\n", + mtd->index); + return; + } + if (mtd->erasesize < record_size) { + printk(KERN_ERR "mtdoops: eraseblock size of MTD partition %d too small\n", + mtd->index); + return; + } + if (mtd->size > MTDOOPS_MAX_MTD_SIZE) { + printk(KERN_ERR "mtdoops: 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) { + printk(KERN_ERR "mtdoops: 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) { + printk(KERN_ERR "mtdoops: 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); + printk(KERN_INFO "mtdoops: 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) + printk(KERN_WARNING "mtdoops: 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) { + printk(KERN_ERR "mtdoops: mtd device (mtddev=name/number) must be supplied\n"); + return -EINVAL; + } + if ((record_size & 4095) != 0) { + printk(KERN_ERR "mtdoops: record_size must be a multiple of 4096\n"); + return -EINVAL; + } + if (record_size < 4096) { + printk(KERN_ERR "mtdoops: 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) { + printk(KERN_ERR "mtdoops: failed to allocate buffer workspace\n"); + return -ENOMEM; + } + memset(cxt->oops_buf, 0xff, record_size); + + 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"); |