RAS: Export helper to get ras_debugfs_dir

Export a getter instead of the debugfs node directly so that, other
in-tree-only RAS modules can use it.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Link: https://lore.kernel.org/r/20240301143748.854090-2-yazen.ghannam@amd.com

ras/debugfs: Fix error checking for debugfs_create_dir()

Check the return value of debugfs_create_dir() properly.

[ bp: Rewrite commit message. ]

Signed-off-by: Osama Muhammad <osmtendev@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230516182927.9171-1-osmtendev@gmail.com

RAS: Fix return value from show_trace()

Documentation/filesystems/seq_file.rst describes the possible return
values from a "show()" function used by single_open().

show_trace() returns the value of "trace_count". This could be
interpreted as "SEQ_SKIP", or just confuse the calling function.

Change to just return "0" to avoid confusing anyone reading this code
and possibly using as a template. Reading "daemon_active" was never
an intended use case.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20221018165900.109029-1-tony.luck@intel.com

RAS: Fix prototype warnings

When building with C=2 and/or W=1, legitimate warnings are issued about
missing prototypes:

CHECK drivers/ras/debugfs.c
drivers/ras/debugfs.c:4:15: warning: symbol 'ras_debugfs_dir' was not declared. Should it be static?
drivers/ras/debugfs.c:8:5: warning: symbol 'ras_userspace_consumers' was not declared. Should it be static?
drivers/ras/debugfs.c:38:12: warning: symbol 'ras_add_daemon_trace' was not declared. Should it be static?
drivers/ras/debugfs.c:54:13: warning: symbol 'ras_debugfs_init' was not declared. Should it be static?
CC drivers/ras/debugfs.o
drivers/ras/debugfs.c:8:5: warning: no previous prototype for 'ras_userspace_consumers' [-Wmissing-prototypes]
8 | int ras_userspace_consumers(void)
| ^~~~~~~~~~~~~~~~~~~~~~~
drivers/ras/debugfs.c:38:12: warning: no previous prototype for 'ras_add_daemon_trace' [-Wmissing-prototypes]
38 | int __init ras_add_daemon_trace(void)
| ^~~~~~~~~~~~~~~~~~~~
drivers/ras/debugfs.c:54:13: warning: no previous prototype for 'ras_debugfs_init' [-Wmissing-prototypes]
54 | void __init ras_debugfs_init(void)
| ^~~~~~~~~~~~~~~~

Provide the proper includes.

[ bp: Take care of the same warnings for cec.c too. ]

Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac@vger.kernel.org
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/7168.1565218769@turing-police

treewide: Add SPDX license identifier for missed files

Add SPDX license identifiers to all files which:

- Have no license information of any form

- Have EXPORT_.*_SYMBOL_GPL inside which was used in the
initial scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

RAS: Add a Corrected Errors Collector

Introduce a simple data structure for collecting correctable errors
along with accessors. More detailed description in the code itself.

The error decoding is done with the decoding chain now and
mce_first_notifier() gets to see the error first and the CEC decides
whether to log it and then the rest of the chain doesn't hear about it -
basically the main reason for the CE collector - or to continue running
the notifiers.

When the CEC hits the action threshold, it will try to soft-offine the
page containing the ECC and then the whole decoding chain gets to see
the error.

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170327093304.10683-5-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

RAS, debugfs: Add debugfs interface for RAS subsystem

Implement a new debugfs interface for RAS susbsystem.
A file named daemon_active is added there accordingly.
This file is used to track if user space daemon accesses
perf/trace interface or not. One can track which daemon
opens it via "lsof /path/to/debugfs/ras/daemon_active".

Signed-off-by: Chen, Gong <gong.chen@linux.intel.com>
Link: http://lkml.kernel.org/r/1402475691-30045-5-git-send-email-gong.chen@linux.intel.com
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Tony Luck <tony.luck@intel.com>