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* pstore: Add file extension to pstore file if compressedAruna Balakrishnaiah2013-08-191-2/+3
| | | | | | | | | | In case decompression fails, add a ".enc.z" to indicate the file has compressed data. This will help user space utilities to figure out the file contents. Signed-off-by: Aruna Balakrishnaiah <aruna@linux.vnet.ibm.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Tony Luck <tony.luck@intel.com>
* efi_pstore: Add a sequence counter to a variable nameSeiji Aguchi2012-11-261-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [Issue] Currently, a variable name, which identifies each entry, consists of type, id and ctime. But if multiple events happens in a short time, a second/third event may fail to log because efi_pstore can't distinguish each event with current variable name. [Solution] A reasonable way to identify all events precisely is introducing a sequence counter to the variable name. The sequence counter has already supported in a pstore layer with "oopscount". So, this patch adds it to a variable name. Also, it is passed to read/erase callbacks of platform drivers in accordance with the modification of the variable name. <before applying this patch> a variable name of first event: dump-type0-1-12345678 a variable name of second event: dump-type0-1-12345678 type:0 id:1 ctime:12345678 If multiple events happen in a short time, efi_pstore can't distinguish them because variable names are same among them. <after applying this patch> it can be distinguishable by adding a sequence counter as follows. a variable name of first event: dump-type0-1-1-12345678 a variable name of Second event: dump-type0-1-2-12345678 type:0 id:1 sequence counter: 1(first event), 2(second event) ctime:12345678 In case of a write callback executed in pstore_console_write(), "0" is added to an argument of the write callback because it just logs all kernel messages and doesn't need to care about multiple events. Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Mike Waychison <mikew@google.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
* pstore/ftrace: Convert to its own enable/disable debugfs knobAnton Vorontsov2012-09-061-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | With this patch we no longer reuse function tracer infrastructure, now we register our own tracer back-end via a debugfs knob. It's a bit more code, but that is the only downside. On the bright side we have: - Ability to make persistent_ram module removable (when needed, we can move ftrace_ops struct into a module). Note that persistent_ram is still not removable for other reasons, but with this patch it's just one thing less to worry about; - Pstore part is more isolated from the generic function tracer. We tried it already by registering our own tracer in available_tracers, but that way we're loosing ability to see the traces while we record them to pstore. This solution is somewhere in the middle: we only register "internal ftracer" back-end, but not the "front-end"; - When there is only pstore tracing enabled, the kernel will only write to the pstore buffer, omitting function tracer buffer (which, of course, still can be enabled via 'echo function > current_tracer'). Suggested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
* pstore: Headers should include all stuff they useAnton Vorontsov2012-07-171-0/+2
| | | | | | | | | | | | | | | | | | | | | Headers should really include all the needed prototypes, types, defines etc. to be self-contained. This is a long-standing issue, but apparently the new tracing code unearthed it (SMP=n is also a prerequisite): In file included from fs/pstore/internal.h:4:0, from fs/pstore/ftrace.c:21: include/linux/pstore.h:43:15: error: field ‘read_mutex’ has incomplete type While at it, I also added the following: linux/types.h -> size_t, phys_addr_t, uXX and friends linux/spinlock.h -> spinlock_t linux/errno.h -> Exxxx linux/time.h -> struct timespec (struct passed by value) struct module and rs_control forward declaration (passed via pointers). Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* pstore: Add persistent function tracingAnton Vorontsov2012-07-171-0/+43
| | | | | | | | | | | | | | | | | | 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 <ccross@android.com> (according to sign-off history). I reworked the driver a little bit, and ported it to pstore. Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* pstore: defer inserting OOPS entries into pstoreLuck, Tony2011-08-161-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | Life is simple for all the kernel terminating types of kmsg_dump call backs - pstore just saves the tail end of the console log. But for "oops" the situation is more complex - the kernel may carry on running (possibly for ever). So we'd like to make the logged copy of the oops appear in the pstore filesystem - so that the user has a handle to clear the entry from the persistent backing store (if we don't, the store may fill with "oops" entries (that are also safely stashed in /var/log/messages) leaving no space for real errors. Current code calls pstore_mkfile() immediately. But this may not be safe. The oops could have happened with arbitrary locks held, or in interrupt or NMI context. So allocating memory and calling into generic filesystem code seems unwise. This patch defers making the entry appear. At the time of the oops, we merely set a flag "pstore_new_entry" noting that a new entry has been added. A periodic timer checks once a minute to see if the flag is set - if so, it schedules a work queue to rescan the backing store and make all new entries appear in the pstore filesystem. Signed-off-by: Tony Luck <tony.luck@intel.com>
* pstore: Extend API for more flexibility in new backendsMatthew Garrett2011-07-221-1/+1
| | | | | | | | | Some pstore implementations may not have a static context, so extend the API to pass the pstore_info struct to all calls and allow for a context pointer. Signed-off-by: Matthew Garrett <mjg@redhat.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
* pstore: use mount option instead sysfs to tweak kmsg_bytesLuck, Tony2011-03-211-2/+1
| | | | | | | | | /sys/fs is a somewhat strange way to tweak what could more obviously be tuned with a mount option. Suggested-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pstore: new filesystem interface to platform persistent storageTony Luck2010-12-281-0/+7
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 <tony.luck@intel.com>
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