linux.git/drivers/acpi/processor_pdc.c, branch v6.18.21

ACPI: processor: Fix uninitialized access of buf in acpi_set_pdc_bits()

2023-09-18T10:16:16+00:00

A bug was introduced during unification of setting CAP_SMP_T_SWCOORD for
the _PDC and _OSC methods.

The third u32 in the buffer is never cleared before setting bits on it.
The memory is not guaranteed to be zero as it was allocated by kmalloc()
instead of kzalloc().

Fix this by initializing the third u32 in the buffer to 0.

Fixes: b9e8d0168a7a ("ACPI: processor: Set CAP_SMP_T_SWCOORD in arch_acpi_set_proc_cap_bits()")
Signed-off-by: Michal Wilczynski 
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki

ACPI: processor: Set CAP_SMP_T_SWCOORD in arch_acpi_set_proc_cap_bits()

2023-07-14T15:59:40+00:00

Currently, ACPI_PROC_CAP_SMP_T_SWCOORD is set in acpi_set_pdc_bits(), but
it is not _PDC-specific. It should be set along with the other processor
capability bits.

Move the setting of ACPI_PROC_CAP_SMP_T_SWCOORD to
arch_acpi_set_proc_cap_bits().

Suggested-by: Rafael J. Wysocki 
Signed-off-by: Michal Wilczynski 
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki

ACPI: processor: Clear C_C2C3_FFH and C_C1_FFH in arch_acpi_set_proc_cap_bits()

2023-07-14T15:59:40+00:00

Currently arch_acpi_set_proc_cap_bits() clears ACPI_PDC_C_C2C3_FFH bit in
case MWAIT instruction is not supported.

It should also clear ACPI_PDC_C_C1_FFH, as when MWAIT is not supported,
C1 is entered by executing the HLT instruction.

Quote from the C_C1_FFH description:

"If set, OSPM is capable of performing native C State instructions (beyond
halt) for the C1 handler in multi-processor configurations". As without
MWAIT there is no native C-state instructions beyond HALT, this bit
should be toggled off."

Clear ACPI_PDC_C_C1_FFH and ACPI_PDC_C_C2C3_FFH in
arch_acpi_set_proc_cap_bits() in case MWAIT is not supported or
overridden.

Remove setting those bits from the processor_pdc.c code.

Suggested-by: Rafael J. Wysocki 
Signed-off-by: Michal Wilczynski 
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki

ACPI: processor: Rename ACPI_PDC symbols

2023-07-14T15:59:40+00:00

The prefix in the names of the ACPI_PDC symbols suggests that they are
only relevant for _PDC, but in fact they can also be used in the _OSC.

Change that prefix to a more generic ACPI_PROC_CAP that will better
reflect the purpose of those symbols as they represent bits in a general
processor capabilities buffer.

Rename pdc_intel.h to proc_cap_intel.h to follow the change of the
symbol name prefix.

No intentional functional impact.

Suggested-by: Rafael J. Wysocki 
Signed-off-by: Michal Wilczynski 
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki

ACPI: processor: Refactor arch_acpi_set_pdc_bits()

2023-07-14T15:59:40+00:00

The capabilities buffer modified by the arch_acpi_set_pdc_bits() is not
_PDC-specific, as it can be used by _OSC too.

Change the name of that function to better reflect its independence from
_PDC and make it take the capabilities buffer address as the argument
directly, without any offset, as _OSC and _PDC use different capabilities
buffer offsets.

No intentional functional impact.

Suggested-by: Rafael J. Wysocki 
Signed-off-by: Michal Wilczynski 
Reviewed-by: Andy Shevchenko 
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki

ACPI: processor: Move processor_physically_present() to acpi_processor.c

2023-07-14T15:59:40+00:00

Since _PDC method is deprecated and a preferred method of communicating
OSPM processor power management capabilities is _OSC, there is a need to
move function checking whether processor is present as this logic is not
_PDC specific.

Move processor_physically_present() to acpi_processor.c.

No intentional functional impact.

Suggested-by: Rafael J. Wysocki 
Signed-off-by: Michal Wilczynski 
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki

ACPI: processor: Move MWAIT quirk out of acpi_processor.c

2023-07-14T15:59:40+00:00

Commit 2a2a64714d9c ("ACPI: Disable MWAIT via DMI on broken Compal board")
introduced a workaround for MWAIT for a specific x86 system.

Move the code outside of acpi_processor.c to acpi/x86/ directory for
consistency and rename the functions associated with it, so their names
start with "acpi_proc_quirk_" to make the goal obvious.

No intentional functional impact.

Suggested-by: Rafael J. Wysocki 
Signed-off-by: Michal Wilczynski 
[ rjw: Subject and changelog edits, two function names changed ]
Signed-off-by: Rafael J. Wysocki

ACPI: processor: Fix evaluating _PDC method when running as Xen dom0

2023-03-22T18:36:31+00:00

In ACPI systems, the OS can direct power management, as opposed to the
firmware.  This OS-directed Power Management is called OSPM.  Part of
telling the firmware that the OS going to direct power management is
making ACPI "_PDC" (Processor Driver Capabilities) calls.  These _PDC
methods must be evaluated for every processor object.  If these _PDC
calls are not completed for every processor it can lead to
inconsistency and later failures in things like the CPU frequency
driver.

In a Xen system, the dom0 kernel is responsible for system-wide power
management.  The dom0 kernel is in charge of OSPM.  However, the
number of CPUs available to dom0 can be different than the number of
CPUs physically present on the system.

This leads to a problem: the dom0 kernel needs to evaluate _PDC for
all the processors, but it can't always see them.

In dom0 kernels, ignore the existing ACPI method for determining if a
processor is physically present because it might not be accurate.
Instead, ask the hypervisor for this information.

Fix this by introducing a custom function to use when running as Xen
dom0 in order to check whether a processor object matches a CPU that's
online.  Such checking is done using the existing information fetched
by the Xen pCPU subsystem, extending it to also store the ACPI ID.

This ensures that _PDC method gets evaluated for all physically online
CPUs, regardless of the number of CPUs made available to dom0.

Fixes: 5d554a7bb064 ("ACPI: processor: add internal processor_physically_present()")
Signed-off-by: Roger Pau Monné 
Reviewed-by: Juergen Gross 
Signed-off-by: Rafael J. Wysocki

ACPI: processor: Get rid of ACPICA message printing

2021-03-08T15:51:19+00:00

The ACPI_DEBUG_PRINT() and ACPI_EXCEPTION() macros are used for
message printing in the ACPICA code and they should not be used
elsewhere.  Special configuration (either kernel command line or
sysfs-based) is needed to see the messages printed by them and
the format of those messages is also special and convoluted.

For this reason, replace all of the ACPI_DEBUG_PRINT() and
ACPI_EXCEPTION() instances in the ACPI processor driver with
corresponding dev_*(), acpi_handle_*() and pr_*() calls depending
on the context in which they appear.

Also drop the ACPI_PROCESSOR_COMPONENT definition that is not going
to be necessary any more.

Signed-off-by: Rafael J. Wysocki 
Reviewed-by: Hanjun Guo

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02T10:10:55+00:00

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 <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart 
Reviewed-by: Philippe Ombredanne 
Reviewed-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman