| commit | 3da0de69628d1341e38608067a9f5198a1e35954 | [log] [tgz] |
|---|---|---|
| author | Andrew Jeffery <andrew@aj.id.au> | Fri Mar 23 12:27:15 2018 +1030 |
| committer | Andrew Jeffery <andrew@aj.id.au> | Wed Apr 04 07:56:23 2018 +0000 |
| tree | 2005a7879167f1a0669b8e7124299ec0aab08316 | |
| parent | 0d087f17f868587ca01259632ba0bd584b66aae4 [diff] |
mboxd_windows: Shrink windows accessing the end of flash
The host may request a window over the end of the flash where the window
size combined with the requested offset exceeds the limit of the flash.
This issue was introduced with the virtual PNOR, as copy_flash() now may
return a size less than requested. This leads to offset requests that
are still block aligned, but the windows may no longer be aligned with
respect to the flash size.
This issue triggers the read error reported from the Petitboot
environment in an earlier commit message:
/ # cat /dev/mtd0 > /dev/null
[ 501.061616288,3] MBOX-FLASH: Bad response code from BMC 2
[ 501.150405995,3] MBOX-FLASH: Error waiting for BMC
cat: read error: Input/output error
/ # echo $?
1
/ #
With the corresponding mboxd trace on the BMC:
[ 1519966031.652036815] Received MBOX command: 4
[ 1519966031.652272613] Host requested flash @ 0x03f1a000
[ 1519966031.652411603] Tried to open read window past flash limit
[ 1519966031.652500088] Couldn't create window mapping for offset 0x03f1a000
[ 1519966031.652607966] Error handling mbox cmd: 4
[ 1519966031.652661421] Writing MBOX response: 2
[ 1519966031.652762229] Error handling MBOX event
Instead, shrink the request such that the resulting window exactly maps
the flash limit, and no further.
Change-Id: Id33ae3b14252eb40240ef1925311f22aceb103b4
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Copyright 2017 IBM
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
This repo contains the protocol definition for the host to BMC mailbox communication specification which can be found in Documentation/mbox_procotol.md.
There is also a reference implementation of a BMC mailbox daemon, the details of which can be found in Documentation/mboxd.md.
Finally there is also an implementation of a mailbox daemon control program, the details of which can be found in Documentation/mboxctl.md.
This codebase is a mix of C (due to its heritage) and C++. This is an ugly split: message logging and error handling can be vastly different inside the same codebase. The aim is to remove the split one way or the other over time and have consistent approaches to solving problems.
phosphor-mboxd is developed as part of the OpenBMC project, which also leads to integration of frameworks such as phosphor-logging. Specifically on phosphor-logging, it's noted that without care we can achieve absurd duplication or irritating splits in where errors are reported, as the C code is not capable of making use of the interfaces provided.
Message logging MUST be done to stdout or stderr, and MUST NOT be done directly via journal APIs or wrappers of the journal APIs.
Rationale:
We have two scenarios where we care about output, with the important restriction that the method must be consistent between C and C++:
In the first case it is desirable that the messages appear in the system journal. To this end, systemd will by default capture stdout and stderr of the launched binary and redirect it to the journal.
In the second case it is desirable that messages be captured by the test runner (make check) for test failure analysis, and it is undesirable for messages to appear in the system journal (as these are tests, not issues affecting the health of the system they are being executed on).
Therefore direct calls to the journal MUST be avoided for the purpose of message logging.
Note: This section specifically targets the use of phosphor-logging's log<T>(). It does not prevent the use of elog<T>().