mtd: mtdoops: panic caused mtdoops to call mtdoops_erase function immediately

The panic function disables the local interrupts, preemption, and all
other processors. When the invoked mtdoops needs to erase a used page,
calling schedule_work() to do it will not work. Instead, just call
mtdoops_erase function immediately.

Tested:
~# echo c > /proc/sysrq-trigger
[ 171.654759] sysrq: Trigger a crash
[ 171.658325] Kernel panic - not syncing: sysrq triggered crash
......
[ 172.406423] mtdoops: not ready 34, 35 (erase immediately)
[ 172.432285] mtdoops: ready 34, 35
[ 172.435633] Rebooting in 10 seconds..

Signed-off-by: Ray Zhang <sgzhang@google.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20221010045549.2221965-4-sgzhang@google.com

mtd: mtdoops: add mtdoops_erase function and move mtdoops_inc_counter to after it

Preparing for next patch with minimal code difference, add mtdoops_erase
function and move mtdoops_inc_counter to after it, with no functional
change.

Signed-off-by: Ray Zhang <sgzhang@google.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20221010045549.2221965-3-sgzhang@google.com

mtd: mtdoops: change printk() to counterpart pr_ functions

To comply with latest kernel code requirement, change printk() to
counterpart pr_ functions in mtdoops driver:
- change printk(INFO) to pr_info()
- change printk(DEBUG) to pr_debug()
- change printk(WARNING) to pr_warn()
- change printk(ERR) to pr_err()

Note that only if dynamic debugging is enabled or DEBUG is defined,
printk(KERN_DEBUG) and pr_debug() are equivalent; Otherwise pr_debug()
is no-op, causing different behavior.

Signed-off-by: Ray Zhang <sgzhang@google.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20221010045549.2221965-2-sgzhang@google.com

mtd: mtdoops: Add a timestamp to the mtdoops header.

On some systems, the oops only has relative time from boot.

Signed-off-by: Jean-Marc Eurin <jmeurin@google.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220425160927.3823016-1-jmeurin@google.com

mtd: mtdoops: Create a header structure for the saved mtdoops.

Create a dump header to enable the addition of fields without having
to modify the rest of the code.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Jean-Marc Eurin <jmeurin@google.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220421234244.2172003-3-jmeurin@google.com

mtd: mtdoops: Fix the size of the header read buffer.

The read buffer size depends on the MTDOOPS_HEADER_SIZE.

Tested: Changed the header size, it doesn't panic, header is still
read/written correctly.

Signed-off-by: Jean-Marc Eurin <jmeurin@google.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220421234244.2172003-2-jmeurin@google.com

mtd: mtdoops: remove unnecessary oom message

Fixes scripts/checkpatch.pl warning:
WARNING: Possible unnecessary 'out of memory' message

Remove it can help us save a bit of memory.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210610021201.15076-1-thunder.leizhen@huawei.com

printk: introduce a kmsg_dump iterator

Rather than storing the iterator information in the registered
kmsg_dumper structure, create a separate iterator structure. The
kmsg_dump_iter structure can reside on the stack of the caller, thus
allowing lockless use of the kmsg_dump functions.

Update code that accesses the kernel logs using the kmsg_dumper
structure to use the new kmsg_dump_iter structure. For kmsg_dumpers,
this also means adding a call to kmsg_dump_rewind() to initialize
the iterator.

All this is in preparation for removal of @logbuf_lock.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Kees Cook <keescook@chromium.org> # pstore
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210303101528.29901-13-john.ogness@linutronix.de

mtd: mtdoops: synchronize kmsg_dumper

The kmsg_dumper can be called from any context and CPU, possibly
from multiple CPUs simultaneously. Since the writing of the buffer
can occur from a later scheduled work queue, the oops buffer must
be protected against simultaneous dumping.

Use an atomic bit to mark when the buffer is protected. Release the
protection in between setting the buffer and the actual writing in
order for a possible panic (immediate write) to be written during
the scheduling of a previous oops (delayed write).

An atomic bit (rather than a spinlock) was chosen so that no
scheduling or preemption side-effects would be introduced. The MTD
kmsg_dumper may dump directly or it may be delayed (via scheduled
work). Depending on the context, different MTD callbacks are used.
For example, mtd_write() expects to be called in a non-atomic
context and may take a mutex.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210303101528.29901-3-john.ogness@linutronix.de

mtd: mtdoops: Don't write panic data twice

If calling mtdoops_write, don't also schedule work to be done later.

Although this appears to not be causing an issue, possibly because the
scheduled work will never get done, it is confusing.

Fixes: 016c1291ce70 ("mtd: mtdoops: do not use mtd->panic_write directly")
Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20200903034217.23079-1-mark.tomlinson@alliedtelesis.co.nz

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 336

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not write to the free
software foundation inc 51 franklin st fifth floor boston ma 02110
1301 usa

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 246 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190530000436.674189849@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

treewide: Use array_size() in vmalloc()

The vmalloc() function has no 2-factor argument form, so multiplication
factors need to be wrapped in array_size(). This patch replaces cases of:

vmalloc(a * b)

with:
vmalloc(array_size(a, b))

as well as handling cases of:

vmalloc(a * b * c)

with:

vmalloc(array3_size(a, b, c))

This does, however, attempt to ignore constant size factors like:

vmalloc(4 * 1024)

though any constants defined via macros get caught up in the conversion.

Any factors with a sizeof() of "unsigned char", "char", and "u8" were
dropped, since they're redundant.

The Coccinelle script used for this was:

// Fix redundant parens around sizeof().
@@
type TYPE;
expression THING, E;
@@

(
vmalloc(
- (sizeof(TYPE)) * E
+ sizeof(TYPE) * E
, ...)
|
vmalloc(
- (sizeof(THING)) * E
+ sizeof(THING) * E
, ...)
)

// Drop single-byte sizes and redundant parens.
@@
expression COUNT;
typedef u8;
typedef __u8;
@@

(
vmalloc(
- sizeof(u8) * (COUNT)
+ COUNT
, ...)
|
vmalloc(
- sizeof(__u8) * (COUNT)
+ COUNT
, ...)
|
vmalloc(
- sizeof(char) * (COUNT)
+ COUNT
, ...)
|
vmalloc(
- sizeof(unsigned char) * (COUNT)
+ COUNT
, ...)
|
vmalloc(
- sizeof(u8) * COUNT
+ COUNT
, ...)
|
vmalloc(
- sizeof(__u8) * COUNT
+ COUNT
, ...)
|
vmalloc(
- sizeof(char) * COUNT
+ COUNT
, ...)
|
vmalloc(
- sizeof(unsigned char) * COUNT
+ COUNT
, ...)
)

// 2-factor product with sizeof(type/expression) and identifier or constant.
@@
type TYPE;
expression THING;
identifier COUNT_ID;
constant COUNT_CONST;
@@

(
vmalloc(
- sizeof(TYPE) * (COUNT_ID)
+ array_size(COUNT_ID, sizeof(TYPE))
, ...)
|
vmalloc(
- sizeof(TYPE) * COUNT_ID
+ array_size(COUNT_ID, sizeof(TYPE))
, ...)
|
vmalloc(
- sizeof(TYPE) * (COUNT_CONST)
+ array_size(COUNT_CONST, sizeof(TYPE))
, ...)
|
vmalloc(
- sizeof(TYPE) * COUNT_CONST
+ array_size(COUNT_CONST, sizeof(TYPE))
, ...)
|
vmalloc(
- sizeof(THING) * (COUNT_ID)
+ array_size(COUNT_ID, sizeof(THING))
, ...)
|
vmalloc(
- sizeof(THING) * COUNT_ID
+ array_size(COUNT_ID, sizeof(THING))
, ...)
|
vmalloc(
- sizeof(THING) * (COUNT_CONST)
+ array_size(COUNT_CONST, sizeof(THING))
, ...)
|
vmalloc(
- sizeof(THING) * COUNT_CONST
+ array_size(COUNT_CONST, sizeof(THING))
, ...)
)

// 2-factor product, only identifiers.
@@
identifier SIZE, COUNT;
@@

vmalloc(
- SIZE * COUNT
+ array_size(COUNT, SIZE)
, ...)

// 3-factor product with 1 sizeof(type) or sizeof(expression), with
// redundant parens removed.
@@
expression THING;
identifier STRIDE, COUNT;
type TYPE;
@@

(
vmalloc(
- sizeof(TYPE) * (COUNT) * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
vmalloc(
- sizeof(TYPE) * (COUNT) * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
vmalloc(
- sizeof(TYPE) * COUNT * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
vmalloc(
- sizeof(TYPE) * COUNT * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
vmalloc(
- sizeof(THING) * (COUNT) * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
vmalloc(
- sizeof(THING) * (COUNT) * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
vmalloc(
- sizeof(THING) * COUNT * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
vmalloc(
- sizeof(THING) * COUNT * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
)

// 3-factor product with 2 sizeof(variable), with redundant parens removed.
@@
expression THING1, THING2;
identifier COUNT;
type TYPE1, TYPE2;
@@

(
vmalloc(
- sizeof(TYPE1) * sizeof(TYPE2) * COUNT
+ array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
, ...)
|
vmalloc(
- sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
, ...)
|
vmalloc(
- sizeof(THING1) * sizeof(THING2) * COUNT
+ array3_size(COUNT, sizeof(THING1), sizeof(THING2))
, ...)
|
vmalloc(
- sizeof(THING1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(THING1), sizeof(THING2))
, ...)
|
vmalloc(
- sizeof(TYPE1) * sizeof(THING2) * COUNT
+ array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
, ...)
|
vmalloc(
- sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
, ...)
)

// 3-factor product, only identifiers, with redundant parens removed.
@@
identifier STRIDE, SIZE, COUNT;
@@

(
vmalloc(
- (COUNT) * STRIDE * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
vmalloc(
- COUNT * (STRIDE) * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
vmalloc(
- COUNT * STRIDE * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
vmalloc(
- (COUNT) * (STRIDE) * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
vmalloc(
- COUNT * (STRIDE) * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
vmalloc(
- (COUNT) * STRIDE * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
vmalloc(
- (COUNT) * (STRIDE) * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
vmalloc(
- COUNT * STRIDE * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
)

// Any remaining multi-factor products, first at least 3-factor products
// when they're not all constants...
@@
expression E1, E2, E3;
constant C1, C2, C3;
@@

(
vmalloc(C1 * C2 * C3, ...)
|
vmalloc(
- E1 * E2 * E3
+ array3_size(E1, E2, E3)
, ...)
)

// And then all remaining 2 factors products when they're not all constants.
@@
expression E1, E2;
constant C1, C2;
@@

(
vmalloc(C1 * C2, ...)
|
vmalloc(
- E1 * E2
+ array_size(E1, E2)
, ...)
)

Signed-off-by: Kees Cook <keescook@chromium.org>

mtd: Unconditionally update ->fail_addr and ->addr in part_erase()

->fail_addr and ->addr can be updated no matter the result of
parent->_erase(), we just need to remove the code doing the same thing
in mtd_erase_callback() to avoid adjusting those fields twice.

Note that this can be done because all MTD users have been converted to
not pass an erase_info->callback() and are thus only taking the
->addr_fail and ->addr fields into account after part_erase() has
returned.

While we're at it, get rid of the erase_info->mtd field which was only
needed to let mtd_erase_callback() get the partition device back.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Reviewed-by: Richard Weinberger <richard@nod.at>

mtd: Stop assuming mtd_erase() is asynchronous

None of the mtd->_erase() implementations work in an asynchronous manner,
so let's simplify MTD users that call mtd_erase(). All they need to do
is check the value returned by mtd_erase() and assume that != 0 means
failure.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Reviewed-by: Richard Weinberger <richard@nod.at>

mtdoops: don't erase flash at each boot

The current version on mtdoops erase first block of mtdoops partition at each
boot if there is no oops stored in flash. This can wear the flash.

When mtdoops start, find_next_position is called to find the next free entry in
the circular buffer. But if the flash is erased, find_next_position don't find
anything (maxcount == 0xffffffff) and start with the first entry after erasing it.

The scanning that is done in find_next_position already track free/used entries.
So if at the end of the scanning we don't find anything, we can start at the
first entry and erased the entry only if it is marked as used.
Most of this is implemented in mtdoops_inc_counter, so to avoid duplicating
code, if we don't find anything we set position to -1. mtdoops_inc_counter with
increment it, erase the entry if needed and start as before with nextpage = 0
and nextcount = 1).

Also during the scan phase, we use the MTDOOPS_KERNMSG_MAGIC to detect corruped
entries.

Signed-off-by: Matthieu Castet <matthieu.castet@parrot@com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

workqueue: deprecate flush[_delayed]_work_sync()

flush[_delayed]_work_sync() are now spurious. Mark them deprecated
and convert all users to flush[_delayed]_work().

If you're cc'd and wondering what's going on: Now all workqueues are
non-reentrant and the regular flushes guarantee that the work item is
not pending or running on any CPU on return, so there's no reason to
use the sync flushes at all and they're going away.

This patch doesn't make any functional difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Mattia Dongili <malattia@linux.it>
Cc: Kent Yoder <key@linux.vnet.ibm.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Karsten Keil <isdn@linux-pingi.de>
Cc: Bryan Wu <bryan.wu@canonical.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-wireless@vger.kernel.org
Cc: Anton Vorontsov <cbou@mail.ru>
Cc: Sangbeom Kim <sbkim73@samsung.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Petr Vandrovec <petr@vandrovec.name>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Avi Kivity <avi@redhat.com>

mtd: mtdoops: refactor loop

We can clean up the loop logic a bit, here. This refactoring was enabled
in part by:

Commit bb4a09866 [mtdoops: clean-up new MTD API usage]

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

kmsg - kmsg_dump() use iterator to receive log buffer content

Provide an iterator to receive the log buffer content, and convert all
kmsg_dump() users to it.

The structured data in the kmsg buffer now contains binary data, which
should no longer be copied verbatim to the kmsg_dump() users.

The iterator should provide reliable access to the buffer data, and also
supports proper log line-aware chunking of data while iterating.

Signed-off-by: Kay Sievers <kay@vrfy.org>
Tested-by: Tony Luck <tony.luck@intel.com>
Reported-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Tested-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

mtdoops: clean-up new MTD API usage

Let's remove useless 'mtd_can_have_bb()' function invocations.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

kexec: remove KMSG_DUMP_KEXEC

KMSG_DUMP_KEXEC is useless because we already save kernel messages inside
/proc/vmcore, and it is unsafe to allow modules to do other stuffs in a
crash dump scenario.

[akpm@linux-foundation.org: fix powerpc build]
Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Reported-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Jarod Wilson <jarod@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mtd: do not use mtd->block_markbad directly

Instead, use the new 'mtd_can_have_bb()', or just rely on 'mtd_block_markbad()'
return code, which will be -EOPNOTSUPP if bad blocks are not supported.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: introduce mtd_can_have_bb helper

This patch introduces new 'mtd_can_have_bb()' helper function which checks
whether the flash can have bad eraseblocks. Then it changes all the
direct 'mtd->block_isbad' use cases with 'mtd_can_have_bb()'.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: mtdoops: do not use mtd->panic_write directly

Instead of checking if 'mtd->panic_write' is defined, call 'mtd_panic_write()'
and check the error code - '-EOPNOTSUPP' will be returned if the function is
not defined.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: introduce mtd_block_markbad interface

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: introduce mtd_block_isbad interface

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: introduce mtd_panic_write interface

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: introduce mtd_write interface

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: introduce mtd_read interface

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: introduce mtd_erase interface

This patch is part of a patch-set which changes the MTD interface
from 'mtd->func()' form to 'mtd_func()' form. We need this because
we want to add common code to to all drivers in the mtd core level,
which is impossible with the current interface when MTD clients
call driver functions like 'read()' or 'write()' directly.

At this point we just introduce a new inline wrapper function, but
later some of them are expected to gain more code. E.g., the input
parameters check should be moved to the wrappers rather than be
duplicated at many drivers.

This particular patch introduced the 'mtd_erase()' interface. The
following patches add all the other interfaces one by one.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtdoops: fix the oops_page_used array size

The array of unsigned long pointed by oops_page_used is allocated
by vmalloc which requires the size to be in bytes.

BITS_PER_LONG is equal to 32.
If we want to allocate memory for 32 pages with one bit per page then
32 / BITS_PER_LONG is equal to 1 byte that is 8 bits.
To fix it we need to multiply the result by sizeof(unsigned long) equal to 4.

Cc: stable@kernel.org
Signed-off-by: Roman Tereshonkov <roman.tereshonkov@nokia.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: mtdoops: skip reading initially bad blocks

Use block_isbad to check and skip the bad blocks reading.
This will allow to get rid of the read errors if bad blocks
are present initially.

Cc: stable@kernel.org
Signed-off-by: Roman Tereshonkov <roman.tereshonkov@nokia.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: utilize `mtd_is_*()' functions

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>

kmsg_dump: constrain mtdoops and ramoops to perform their actions only for KMSG_DUMP_PANIC

This series aims to develop logging facility for enterprise use.

It is important to save kernel messages reliably on enterprise system
because they are helpful for diagnosing system.

This series add kmsg_dump() to the paths loosing kernel messages. The use
case is the following.

[Use case of reboot/poweroff/halt/emergency_restart]

My company has often experienced the followings in our support service.
- Customer's system suddenly reboots.
- Customers ask us to investigate the reason of the reboot.

We recognize the fact itself because boot messages remain in
/var/log/messages. However, we can't investigate the reason why the
system rebooted, because the last messages don't remain. And off course
we can't explain the reason.

We can solve above problem with this patch as follows.

Case1: reboot with command
- We can see "Restarting system with command:" or ""Restarting system.".

Case2: halt with command
- We can see "System halted.".

Case3: poweroff with command
- We can see " Power down.".

Case4: emergency_restart with sysrq.
- We can see "Sysrq:" outputted in __handle_sysrq().

Case5: emergency_restart with softdog.
- We can see "Initiating system reboot" in watchdog_fire().

So, we can distinguish the reason of reboot, poweroff, halt and emergency_restart.

If customer executed reboot command, you may think the customer should
know the fact. However, they often claim they don't execute the command
when they rebooted system by mistake.

No message remains on the current Linux kernel, so we can't show the proof
to the customer. This patch improves this situation.

This patch:

Alters mtdoops and ramoops to perform their actions only for
KMSG_DUMP_PANIC, KMSG_DUMP_OOPS and KMSG_DUMP_KEXEC because they would
like to log crashes only.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Marco Stornelli <marco.stornelli@gmail.com>
Reviewed-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mtd: don't use flush_scheduled_work()

flush_scheduled_work() is deprecated and scheduled to be removed.
Directly flush cxt->work_{erase|write} on removal instead.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: Update copyright notices

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

mtd: Remove unnecessary comparisons with MAX_MTD_DEVICES

MAX_MTD_DEVICES is about to be removed.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

kmsg_dump: Dump on crash_kexec as well

crash_kexec gets called before kmsg_dump(KMSG_DUMP_OOPS) if
panic_on_oops is set, so the kernel log buffer is not stored
for this case.

This patch adds a KMSG_DUMP_KEXEC dump type which gets called
when crash_kexec() is invoked. To avoid getting double dumps,
the old KMSG_DUMP_PANIC is moved below crash_kexec(). The
mtdoops driver is modified to handle KMSG_DUMP_KEXEC in the
same way as a panic.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Simon Kagstrom <simon.kagstrom@netinsight.net>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: mtdoops: refactor as a kmsg_dumper

The last messages which happens before a crash might contain interesting
information about the crash. This patch reworks mtdoops using the
kmsg_dumper support instead of a console, which simplifies the code and
also includes the messages before the oops started.

On oops callbacks, the MTD device write is scheduled in a work queue (to
be able to use the regular mtd->write call), while panics call
mtd->panic_write directly. Thus, if panic_on_oops is set, the oops will
be written out during the panic.

A parameter to specify which mtd device to use (number or name), as well
as a flag, writable at runtime, to toggle wheter to dump oopses or only
panics (since oopses can often be handled by regular syslog).

The patch was massaged and amended by Artem.

Signed-off-by: Simon Kagstrom <simon.kagstrom@netinsight.net>
Reviewed-by: Anders Grafstrom <anders.grafstrom@netinsight.net>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: mtdoops: make record size configurable

The main justification for this is to allow catching long messages
during a panic, where the top part might otherwise be lost since moving
to the next block can require a flash erase.

Signed-off-by: Simon Kagstrom <simon.kagstrom@netinsight.net>
Reviewed-by: Anders Grafstrom <anders.grafstrom@netinsight.net>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: mtdoops: limit the maximum mtd partition size

Make the maximum mtdoops partition size to be 8MiB. Indeed, it does
not make sense to use anything larger than that anyway. This limit
makes it possible to catch stupid mistakes where the user gives e.g.,
a rootfs partition to mtdoops (which will happily erase it).

Signed-off-by: Simon Kagstrom <simon.kagstrom@netinsight.net>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: mtdoops: keep track of used/unused pages in an array

This patch makes mtdoops keep track of used/unused pages in an array
instead of scanning the flash after a write. The advantage with this
approach is that it avoids calling mtd->read on a panic, which is not
possible for all mtd drivers.

Signed-off-by: Simon Kagstrom <simon.kagstrom@netinsight.net>
Reviewed-by: Anders Grafstrom <anders.grafstrom@netinsight.net>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: mtdoops: several minor cleanups

While looking into the mtdoops module, I've spotted several minor
imperfections. This patch addresses them. Namely:

1. Remove several trailing white-spaces and tabs
2. Check 'vmalloc()' return code straight away, not several lines
below in the 'mtdoops_console_init()' function.
3. Clean up printks - make them more consistent and use the same
code formatting style for them.
4. Remove silly style of putting brackets around everything in
"if" operators.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Cc: Simon Kagstrom <simon.kagstrom@netinsight.net>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

[MTD] mtdoops: fix a bit of spin lock usage

- do not leave spin lock locked
- initialise spin lock

Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Acked-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

[MTD] mtdoops: allow MTD selection by name

MTD's have both an index number and a name. Formerly,
the MTD selected for mtdoops was done only by index
number. With this patch, a name can be used instead.

For example, the kernel command line:

console=ttyMTD5

selects MTD 5 for mtdoops. But now this is also possible:

console=ttyMTD,log

which selects the MTD named "log" for mtdoops.

This has the advantage that partitions can be added or
removed that would affect the MTD index number but not the
name, without having to then change the kernel command line.

Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
Acked-by: Richard Purdie <rpurdie@linux.intel.com>
Acked-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

[MTD] update internal API to support 64-bit device size

MTD internal API presently uses 32-bit values to represent
device size. This patch updates them to 64-bits but leaves
the external API unchanged. Extending the external API
is a separate issue for several reasons. First, no one
needs it at the moment. Secondly, whether the implementation
is done with IOCTLs, sysfs or both is still debated. Thirdly
external API changes require the internal API to be accepted
first.

Note that although the MTD API will be able to support 64-bit
device sizes, existing drivers do not and are not required
to do so, although NAND base has been updated.

In general, changing from 32-bit to 64-bit values cause little
or no changes to the majority of the code with the following
exceptions:
- printk message formats
- division and modulus of 64-bit values
- NAND base support
- 32-bit local variables used by mtdpart and mtdconcat
- naughtily assuming one structure maps to another
in MEMERASE ioctl

Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

[MTD] mtdoops: Fix a bug where block may not be erased

This makes the driver erase a block when it doesn't find any
existing saved log messages which is safer than assuming the
flash was already erased.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

[MTD] mtdoops: Add a magic number to logged kernel oops

Add a magic number to logged kernel oops messages so that they
can be more accurately detected rather than just having to rely
on the sequence number. This also allows easier detection of
saved crashes by userspace.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

[MTD] mtdoops: Fix an off by one error

Fix an off by one error in the mtdoops driver

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

[MTD] mtdoops.c: make struct oops_cxt static again

struct oops_cxt needlessly became global.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[MTD] Fix mtdoops.c compilation

drivers/mtd/mtdoops.c: In function ‘mtdoops_console_sync’:
drivers/mtd/mtdoops.c:329: error: implicit declaration of function ‘in_interrupt’

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[MTD] mtdoops: Use the panic_write function when present

When the MTD provides a panic_write function, use it.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[MTD] mtdoops: Various minor cleanups

Various minor cleaups to mtdoops:
* Don't support the mtd->erasesize < OOPS_PAGE_SIZE case
* Tweak printks and make the device mtdoops connects to more visible
* CON_PRINTBUFFER flag is uneeded

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[MTD] mtdoops: Ensure sequential write to the buffer

Add a spinlock to ensure writes to the mtdoops buffer memory are
sequential and don't race.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[MTD] mtdoops: Perform write operations in a workqueue

Writing to the flash needs to be done in a workqueue. The console
write functions may be called in any context which can lead to
lockups otherwise.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[MTD] mtdoops: Add further error return code checking

Add further error return code checks to the mtdoops driver.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[MTD] mtdoops cleanup

Use memcpy instead of open coding a copy loop.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[MTD] mtdoops printk warning fixes

drivers/mtd/mtdoops.c: In function 'mtdoops_inc_counter':
drivers/mtd/mtdoops.c:109: warning: format '%d' expects type 'int', but argument 3 has type 'size_t'
drivers/mtd/mtdoops.c: In function 'mtdoops_console_sync':
drivers/mtd/mtdoops.c:277: warning: format '%d' expects type 'int', but argument 3 has type 'size_t'

someone buy Dave an x86_64 box.

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[MTD] Add sync/unblank function to mtdoops

mtdoops wasn't ensuring data was flushed to flash in crash situations
after recent changes in mainline kernels as tracking the
oops_in_progress variable was no longer enough. We can use the "unblank"
console call as a sync call to tell us to write out the buffer though.

Therefore add a sync function to mtdoops and call this when console
unblank events occur.

Signed-off-by: Richard Purdie <rpurdie@openedhand.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[MTD] oops and panic message logging to MTD device

Kernel oops and panic messages are invaluable when debugging crashes.
These messages often don't make it to flash based logging methods (say a
syslog on jffs2) due to the overheads involved in writing to flash.

This patch allows you to turn an MTD partition into a circular log
buffer where kernel oops and panic messages are written to. The messages
are obtained by registering a console driver and checking
oops_in_progress. Erases are performed in advance to maximise the
chances of a saving messages.

To activate it, add console=ttyMTDx to the kernel commandline (where x
is the mtd device number to use).

Signed-off-by: Richard Purdie <rpurdie@openedhand.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>