linux-stable.git/drivers/acpi/cppc_acpi.c, branch linux-4.9.y

ACPI: CPPC: Avoid out of bounds access when parsing _CPC data

2022-04-20T07:06:40+00:00

commit 40d8abf364bcab23bc715a9221a3c8623956257b upstream.

If the NumEntries field in the _CPC return package is less than 2, do
not attempt to access the "Revision" element of that package, because
it may not be present then.

Fixes: 337aadff8e45 ("ACPI: Introduce CPU performance controls using CPPC")
BugLink: https://lore.kernel.org/lkml/20220322143534.GC32582@xsang-OptiPlex-9020/
Reported-by: kernel test robot 
Signed-off-by: Rafael J. Wysocki 
Reviewed-by: Huang Rui 
Signed-off-by: Greg Kroah-Hartman

ACPI: CPPC: Fix reference count leak in acpi_cppc_processor_probe()

2020-06-20T08:24:09+00:00

commit 4d8be4bc94f74bb7d096e1c2e44457b530d5a170 upstream.

kobject_init_and_add() takes reference even when it fails.
If this function returns an error, kobject_put() must be called to
properly clean up the memory associated with the object. Previous
commit "b8eb718348b8" fixed a similar problem.

Fixes: 158c998ea44b ("ACPI / CPPC: add sysfs support to compute delivered performance")
Signed-off-by: Qiushi Wu 
Cc: 4.10+  # 4.10+
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

ACPI / CPPC: do not require the _PSD method

2019-10-05T10:30:24+00:00

[ Upstream commit 4c4cdc4c63853fee48c02e25c8605fb65a6c9924 ]

According to the ACPI 6.3 specification, the _PSD method is optional
when using CPPC.  The underlying assumption is that each CPU can change
frequency independently from all other CPUs; _PSD is provided to tell
the OS that some processors can NOT do that.

However, the acpi_get_psd() function returns ENODEV if there is no _PSD
method present, or an ACPI error status if an error occurs when evaluating
_PSD, if present.  This makes _PSD mandatory when using CPPC, in violation
of the specification, and only on Linux.

This has forced some firmware writers to provide a dummy _PSD, even though
it is irrelevant, but only because Linux requires it; other OSPMs follow
the spec.  We really do not want to have OS specific ACPI tables, though.

So, correct acpi_get_psd() so that it does not return an error if there
is no _PSD method present, but does return a failure when the method can
not be executed properly.  This allows _PSD to be optional as it should
be.

Signed-off-by: Al Stone 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Sasha Levin

ACPI / CPPC: set an error code on probe error path

2017-01-19T19:18:07+00:00

commit 501634759d55a5b56967de6d9465acf02bbc3565 upstream.

We should return -EINVAL (instead of 0) if get_cpu_device() fails.

Fixes: 158c998ea44b (ACPI / CPPC: add sysfs support to compute delivered performance)
Signed-off-by: Dan Carpenter 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

ACPI / CPPC: Support PCC with interrupt flag

2016-09-16T23:14:24+00:00

For PCC mailbox with interrupt flag, CPPC should call mbox_chan_txdone()
function to notify the mailbox framework about TX completion.

Signed-off-by: Hoan Tran 
Reviewed-by: Prashanth Prakash 
Signed-off-by: Rafael J. Wysocki

ACPI / CPPC: Add prefix cppc to cpudata structure name

2016-09-08T21:02:15+00:00

Since struct cpudata is defined in a header file, add prefix cppc_ to
make it not a generic name. Otherwise it causes compile issue in locally
define structure with the same name.

Signed-off-by: Srinivas Pandruvada 
Signed-off-by: Rafael J. Wysocki

ACPI / CPPC: Add support for functional fixed hardware address

2016-09-08T21:02:14+00:00

The CPPC registers can also be accessed via functional fixed hardware
addresse(FFH) in X86. Add support by modifying cpc_read and cpc_write to
be able to read/write MSRs on x86 platform on per cpu basis.
Also with this change, acpi_cppc_processor_probe doesn't bail out if
address space id is not equal to PCC or memory address space and FFH
is supported on the system.

Signed-off-by: Srinivas Pandruvada 
Signed-off-by: Rafael J. Wysocki

ACPI / CPPC: check for error bit in PCC status field

2016-08-30T23:02:34+00:00

PCC status field exposes an error bit(2) to indicate any errors during
the execution of last comamnd. This patch checks the error bit before
notifying success/failure to the cpufreq driver.

Signed-off-by: Prashanth Prakash 
Signed-off-by: Rafael J. Wysocki

ACPI / CPPC: move all PCC related information into pcc_data

2016-08-30T23:02:34+00:00

There are several global variables in cppc driver that are related
to PCC channel used for CPPC. This patch collects all such
information into a single consolidated structure(cppc_pcc_data).

Signed-off-by: Prashanth Prakash 
Signed-off-by: Rafael J. Wysocki

ACPI / CPPC: add sysfs support to compute delivered performance

2016-08-30T23:02:34+00:00

The CPPC tables contain entries for per CPU feedback counters which
allows us to compute the delivered performance over a given interval
of time.

The math for delivered performance per the CPPCv5.0+ spec is:
  reference perf * delta(delivered perf ctr)/delta(ref perf ctr)

Maintaining deltas of the counters in the kernel is messy, as it
depends on when the reads are triggered. (e.g. via the cpufreq
->get() interface). Also the ->get() interace only returns one
value, so cant return raw values. So instead, leave it to userspace
to keep track of raw values and do its math for CPUs it cares about.

delivered and reference perf counters are exposed via the same
sysfs file to avoid the potential "skid", if these values are read
individually from userspace.

Signed-off-by: Prashanth Prakash 
Signed-off-by: Ashwin Chaugule 
Signed-off-by: Rafael J. Wysocki