31 May, 2020
2 commits
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pstore/blk is similar to pstore/ram, but uses a block device as the
storage rather than persistent ram.The pstore/blk backend solves two common use-cases that used to preclude
using pstore/ram:
- not all devices have a battery that could be used to persist
regular RAM across power failures.
- most embedded intelligent equipment have no persistent ram, which
increases costs, instead preferring cheaper solutions, like block
devices.pstore/blk provides separate configurations for the end user and for the
block drivers. User configuration determines how pstore/blk operates, such
as record sizes, max kmsg dump reasons, etc. These can be set by Kconfig
and/or module parameters, but module parameter have priority over Kconfig.
Driver configuration covers all the details about the target block device,
such as total size of the device and how to perform read/write operations.
These are provided by block drivers, calling pstore_register_blkdev(),
including an optional panic_write callback used to bypass regular IO
APIs in an effort to avoid potentially destabilized kernel code during
a panic.Signed-off-by: WeiXiong Liao
Link: https://lore.kernel.org/lkml/20200511233229.27745-3-keescook@chromium.org/
Co-developed-by: Kees Cook
Signed-off-by: Kees Cook -
Implement a common set of APIs needed to support pstore storage zones,
based on how ramoops is designed. This will be used by pstore/blk with
the intention of migrating pstore/ram in the future.Signed-off-by: WeiXiong Liao
Link: https://lore.kernel.org/lkml/20200511233229.27745-2-keescook@chromium.org/
Co-developed-by: Kees Cook
Signed-off-by: Kees Cook
02 Nov, 2017
1 commit
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Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.By default all files without license information are under the default
license of the kernel, which is GPL version 2.Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if
Reviewed-by: Philippe Ombredanne
Reviewed-by: Thomas Gleixner
Signed-off-by: Greg Kroah-Hartman
22 Oct, 2015
1 commit
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pstore doesn't support unregistering yet. It was marked as TODO.
This patch adds some code to fix it:
1) Add functions to unregister kmsg/console/ftrace/pmsg.
2) Add a function to free compression buffer.
3) Unmap the memory and free it.
4) Add a function to unregister pstore filesystem.Signed-off-by: Geliang Tang
Acked-by: Kees Cook
[Removed __exit annotation from ramoops_remove(). Reported by Arnd Bergmann]
Signed-off-by: Tony Luck
17 Jan, 2015
1 commit
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A secured user-space accessible pstore object. Writes
to /dev/pmsg0 are appended to the buffer, on reboot
the persistent contents are available in
/sys/fs/pstore/pmsg-ramoops-[ID].One possible use is syslogd, or other daemon, can
write messages, then on reboot provides a means to
triage user-space activities leading up to a panic
as a companion to the pstore dmesg or console logs.Signed-off-by: Mark Salyzyn
Acked-by: Kees Cook
Signed-off-by: Tony Luck
18 Jul, 2012
1 commit
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With this support kernel can save function call chain log into a
persistent ram buffer that can be decoded and dumped after reboot
through pstore filesystem. It can be used to determine what function
was last called before a reset or panic.We store the log in a binary format and then decode it at read time.
p.s.
Mostly the code comes from trace_persistent.c driver found in the
Android git tree, written by Colin Cross
(according to sign-off history). I reworked the driver a little bit,
and ported it to pstore.Signed-off-by: Anton Vorontsov
Signed-off-by: Greg Kroah-Hartman
17 May, 2012
1 commit
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This is a first step for adding ECC support for pstore RAM backend: we
will use the persistent_ram routines, kindly provided by Google.Basically, persistent_ram is a set of helper routines to deal with the
[optionally] ECC-protected persistent ram regions.A bit of Makefile, Kconfig and header files adjustments were needed
because of the move.Signed-off-by: Anton Vorontsov
Acked-by: Kees Cook
Signed-off-by: Greg Kroah-Hartman
16 May, 2012
1 commit
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Since ramoops was converted to pstore, it has nothing to do with character
devices nowadays. Instead, today it is just a RAM backend for pstore.The patch just moves things around. There are a few changes were needed
because of the move:1. Kconfig and Makefiles fixups, of course.
2. In pstore/ram.c we have to play a bit with MODULE_PARAM_PREFIX, this
is needed to keep user experience the same as with ramoops driver
(i.e. so that ramoops.foo kernel command line arguments would still
work).Signed-off-by: Anton Vorontsov
Acked-by: Marco Stornelli
Acked-by: Kees Cook
Signed-off-by: Greg Kroah-Hartman
29 Dec, 2010
1 commit
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Some platforms have a small amount of non-volatile storage that
can be used to store information useful to diagnose the cause of
a system crash. This is the generic part of a file system interface
that presents information from the crash as a series of files in
/dev/pstore. Once the information has been seen, the underlying
storage is freed by deleting the files.Signed-off-by: Tony Luck
