Commit Graph

25 Commits

Author SHA1 Message Date
Linus Torvalds cf3c8f84d1 More power manadement updates for 5.6-rc1
Prevent cpufreq from creating excessively large stack frames and fix
 the handling of devices deleted during system-wide resume in the PM
 core (Rafael Wysocki), revert a problematic commit affecting the
 cpupower utility and correct its man page (Thomas Renninger,
 Brahadambal Srinivasan), and improve the intel_pstate_tracer
 utility (Doug Smythies).
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Merge tag 'pm-5.6-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull more power manadement updates from Rafael Wysocki:
 "Prevent cpufreq from creating excessively large stack frames and fix
  the handling of devices deleted during system-wide resume in the PM
  core (Rafael Wysocki), revert a problematic commit affecting the
  cpupower utility and correct its man page (Thomas Renninger,
  Brahadambal Srinivasan), and improve the intel_pstate_tracer utility
  (Doug Smythies)"

* tag 'pm-5.6-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  tools/power/x86/intel_pstate_tracer: change several graphs to autoscale y-axis
  tools/power/x86/intel_pstate_tracer: changes for python 3 compatibility
  Correction to manpage of cpupower
  cpufreq: Avoid creating excessively large stack frames
  PM: core: Fix handling of devices deleted during system-wide resume
  cpupower: Revert library ABI changes from commit ae2917093f
2020-01-31 14:36:35 -08:00
Rafael J. Wysocki 1e4f63aecb cpufreq: Avoid creating excessively large stack frames
In the process of modifying a cpufreq policy, the cpufreq core makes
a copy of it including all of the internals which is stored on the
CPU stack.  Because struct cpufreq_policy is relatively large, this
may cause the size of the stack frame to exceed the 2 KB limit and
so the GCC complains when -Wframe-larger-than= is used.

In fact, it is not necessary to copy the entire policy structure
in order to modify it, however.

First, because cpufreq_set_policy() obtains the min and max policy
limits from frequency QoS now, it is not necessary to pass the limits
to it from the callers.  The only things that need to be passed to it
from there are the new governor pointer or (if there is a built-in
governor in the driver) the "policy" value representing the governor
choice.  They both can be passed as individual arguments, though, so
make cpufreq_set_policy() take them this way and rework its callers
accordingly.  This avoids making copies of cpufreq policies in the
callers of cpufreq_set_policy().

Second, cpufreq_set_policy() still needs to pass the new policy
data to the ->verify() callback of the cpufreq driver whose task
is to sanitize the min and max policy limits.  It still does not
need to make a full copy of struct cpufreq_policy for this purpose,
but it needs to pass a few items from it to the driver in case they
are needed (different drivers have different needs in that respect
and all of them have to be covered).  For this reason, introduce
struct cpufreq_policy_data to hold copies of the members of
struct cpufreq_policy used by the existing ->verify() driver
callbacks and pass a pointer to a temporary structure of that
type to ->verify() (instead of passing a pointer to full struct
cpufreq_policy to it).

While at it, notice that intel_pstate and longrun don't really need
to verify the "policy" value in struct cpufreq_policy, so drop those
check from them to avoid copying "policy" into struct
cpufreq_policy_data (which allows it to be slightly smaller).

Also while at it fix up white space in a couple of places and make
cpufreq_set_policy() static (as it can be so).

Fixes: 3000ce3c52 ("cpufreq: Use per-policy frequency QoS")
Link: https://lore.kernel.org/linux-pm/CAMuHMdX6-jb1W8uC2_237m8ctCpsnGp=JCxqt8pCWVqNXHmkVg@mail.gmail.com
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2020-01-27 10:33:33 +01:00
Christoph Hellwig 4bdc0d676a remove ioremap_nocache and devm_ioremap_nocache
ioremap has provided non-cached semantics by default since the Linux 2.6
days, so remove the additional ioremap_nocache interface.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
2020-01-06 09:45:59 +01:00
David Arcari 2d4a79ae34 cpufreq: pcc-cpufreq: Fail initialization if driver cannot be registered
Make pcc_cpufreq_init() return error codes when the driver cannot be
registered.  Otherwise the driver can shows up loaded via lsmod even
though it failed initialization.  This is confusing to the user.

Signed-off-by: David Arcari <darcari@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-06-17 12:25:30 +02:00
Yangtao Li cd284ae36b cpufreq: pcc-cpufreq: remove unneeded semicolon
The semicolon is unneeded, so remove it.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-02-18 10:27:38 +05:30
Rafael J. Wysocki 6e926363fc Merge back cpufreq material for 4.19. 2018-07-25 13:28:01 +02:00
Rafael J. Wysocki 95d6c0857e cpufreq: intel_pstate: Register when ACPI PCCH is present
Currently, intel_pstate doesn't register if _PSS is not present on
HP Proliant systems, because it expects the firmware to take over
CPU performance scaling in that case.  However, if ACPI PCCH is
present, the firmware expects the kernel to use it for CPU
performance scaling and the pcc-cpufreq driver is loaded for that.

Unfortunately, the firmware interface used by that driver is not
scalable for fundamental reasons, so pcc-cpufreq is way suboptimal
on systems with more than just a few CPUs.  In fact, it is better to
avoid using it at all.

For this reason, modify intel_pstate to look for ACPI PCCH if _PSS
is not present and register if it is there.  Also prevent the
pcc-cpufreq driver from trying to initialize itself if intel_pstate
has been registered already.

Fixes: fbbcdc0744 (intel_pstate: skip the driver if ACPI has power mgmt option)
Reported-by: Andreas Herrmann <aherrmann@suse.com>
Reviewed-by: Andreas Herrmann <aherrmann@suse.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Tested-by: Andreas Herrmann <aherrmann@suse.com>
Cc: 4.16+ <stable@vger.kernel.org> # 4.16+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-07-18 13:38:37 +02:00
Rafael J. Wysocki 4d81b0f9e6 cpufreq: pcc-cpufreq: Disable dynamic scaling on many-CPU systems
The firmware interface used by the pcc-cpufreq driver is
fundamentally not scalable and using it for dynamic CPU performance
scaling on systems with many CPUs leads to degraded performance.

For this reason, disable dynamic CPU performance scaling on systems
with pcc-cpufreq where the number of CPUs present at the driver init
time is greater than 4.  Also make the driver print corresponding
complaints to the kernel log.

Reported-by: Andreas Herrmann <aherrmann@suse.com>
Tested-by: Andreas Herrmann <aherrmann@suse.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-07-18 10:15:07 +02:00
Andreas Herrmann da7d3abe1c Revert "cpufreq: pcc-cpufreq: update default value of cpuinfo_transition_latency"
This reverts commit 790d849bf8.

Using a v4.7-rc7 kernel on a HP ProLiant triggered following messages

 pcc-cpufreq: (v1.10.00) driver loaded with frequency limits: 1200 MHz, 2800 MHz
 cpufreq: ondemand governor failed, too long transition latency of HW, fallback to performance governor

The last line was shown for each CPU in the system.
Testing v4.5 (where commit 790d849b was integrated) triggered
similar messages. Same behaviour on a 2nd HP Proliant system.

So commit 790d849bf (cpufreq: pcc-cpufreq: update default value of
cpuinfo_transition_latency) causes the system to use performance
governor which, I guess, was not the intention of the patch.

Enabling debug output in pcc-cpufreq provides following verbose output:

 pcc-cpufreq: (v1.10.00) driver loaded with frequency limits: 1200 MHz, 2800 MHz
 pcc_get_offset: for CPU 0: pcc_cpu_data input_offset: 0x44, pcc_cpu_data output_offset: 0x48
 init: policy->max is 2800000, policy->min is 1200000
 get: get_freq for CPU 0
 get: SUCCESS: (virtual) output_offset for cpu 0 is 0xffffc9000d7c0048, contains a value of: 0xff06. Speed is: 168000 MHz
 cpufreq: ondemand governor failed, too long transition latency of HW, fallback to performance governor
 target: CPU 0 should go to target freq: 2800000 (virtual) input_offset is 0xffffc9000d7c0044
 target: was SUCCESSFUL for cpu 0

I am asking to revert 790d849bf to re-enable usage of ondemand
governor with pcc-cpufreq.

Fixes: 790d849bf (cpufreq: pcc-cpufreq: update default value of cpuinfo_transition_latency)
CC: <stable@vger.kernel.org> # 4.5+
Signed-off-by: Andreas Herrmann <aherrmann@suse.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-07-22 23:51:06 +02:00
Mike Galbraith 3c67a829bd cpufreq: pcc-cpufreq: Fix doorbell.access_width
Commit 920de6ebfa (ACPICA: Hardware: Enhance
acpi_hw_validate_register() with access_width/bit_offset awareness)
apparently exposed a latent bug, doorbell.access_width is initialized
to 64, but per Lv Zheng, it should be 4, and indeed, making that
change does bring pcc-cpufreq back to life.

Fixes: 920de6ebfa (ACPICA: Hardware: Enhance acpi_hw_validate_register() with access_width/bit_offset awareness)
Suggested-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-06-23 23:09:51 +02:00
Jacob Tanenbaum 790d849bf8 cpufreq: pcc-cpufreq: update default value of cpuinfo_transition_latency
The cpufreq documentation specifies

policy->cpuinfo.transition_latency   the time it takes on this CPU to
                                switch between two frequencies in
                                nanoseconds (if appropriate, else
                                specify CPUFREQ_ETERNAL)

currently pcc-cpufreq does not expose the value and sets it to zero. I
changed the pcc-cpufreq driver and it's documentation to conform to the
default value specified in Documentation/cpu-freq/cpu-drivers.txt

Signed-off-by: Jacob Tanenbaum <jtanenba@redhat.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-12-10 00:17:03 +01:00
Lenny Szubowicz 7e7e8fe698 cpufreq: pcc: Enable autoload of pcc-cpufreq for ACPI processors
The pcc-cpufreq driver is not automatically loaded on systems where
the platform's power management setting requires this driver.
Instead, on those systems no CPU frequency driver is registered and
active.

Make the autoloading matching criteria for loading the pcc-cpufreq
driver the same as done in acpi-cpufreq by commit c655affbd5
("ACPI / cpufreq: Add ACPI processor device IDs to acpi-cpufreq").

x86 CPU frequency drivers are now typically autoloaded by specifying
MODULE_DEVICE_TABLE entries and x86cpu model specific matching.
But pcc-cpufreq was omitted when acpi-cpufreq and other drivers were
changed to use this approach.

Both acpi-cpufreq and pcc-cpufreq depend on a distinct and mutually
exclusive set of ACPI methods which are not directly tied to specific
processor model numbers. Both of these drivers have init routines
which look for their required ACPI methods. As a result, only the
appropriate driver registers as the cpu frequency driver and the other
one ends up being unloaded.

Tested on various systems where acpi-cpufreq, intel_pstate, and
pcc-cpufreq are the expected cpu frequency drivers.

Signed-off-by: Lenny Szubowicz <lszubowi@redhat.com>
Signed-off-by: Joseph Szczypek <joseph.szczypek@hp.com>
Reported-by: Trinh Dao <trinh.dao@hp.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-11-14 00:16:25 +01:00
Rafael J. Wysocki e65b5ddba8 cpufreq: pcc-cpufreq: Fix wait_event() under spinlock
Fix the following bug introduced by commit 8fec051eea (cpufreq:
Convert existing drivers to use cpufreq_freq_transition_{begin|end})
that forgot to move the spin_lock() in pcc_cpufreq_target() past
cpufreq_freq_transition_begin() which calls wait_event():

BUG: sleeping function called from invalid context at drivers/cpufreq/cpufreq.c:370
in_atomic(): 1, irqs_disabled(): 0, pid: 2636, name: modprobe
Preemption disabled at:[<ffffffffa04d74d7>] pcc_cpufreq_target+0x27/0x200 [pcc_cpufreq]
[   51.025044]
CPU: 57 PID: 2636 Comm: modprobe Tainted: G            E  3.17.0-default #7
Hardware name: Hewlett-Packard ProLiant DL980 G7, BIOS P66 07/07/2010
 00000000ffffffff ffff88026c46b828 ffffffff81589dbd 0000000000000000
 ffff880037978090 ffff88026c46b848 ffffffff8108e1df ffff880037978090
 0000000000000000 ffff88026c46b878 ffffffff8108e298 ffff88026d73ec00
Call Trace:
 [<ffffffff81589dbd>] dump_stack+0x4d/0x90
 [<ffffffff8108e1df>] ___might_sleep+0x10f/0x180
 [<ffffffff8108e298>] __might_sleep+0x48/0xd0
 [<ffffffff8145b905>] cpufreq_freq_transition_begin+0x75/0x140 drivers/cpufreq/cpufreq.c:370 wait_event(policy->transition_wait, !policy->transition_ongoing);
 [<ffffffff8108fc99>] ? preempt_count_add+0xb9/0xc0
 [<ffffffffa04d7513>] pcc_cpufreq_target+0x63/0x200 [pcc_cpufreq] drivers/cpufreq/pcc-cpufreq.c:207 spin_lock(&pcc_lock);
 [<ffffffff810e0d0f>] ? update_ts_time_stats+0x7f/0xb0
 [<ffffffff8145be55>] __cpufreq_driver_target+0x85/0x170
 [<ffffffff8145e4c8>] od_check_cpu+0xa8/0xb0
 [<ffffffff8145ef10>] dbs_check_cpu+0x180/0x1d0
 [<ffffffff8145f310>] cpufreq_governor_dbs+0x3b0/0x720
 [<ffffffff8145ebe3>] od_cpufreq_governor_dbs+0x33/0xe0
 [<ffffffff814593d9>] __cpufreq_governor+0xa9/0x210
 [<ffffffff81459fb2>] cpufreq_set_policy+0x1e2/0x2e0
 [<ffffffff8145a6cc>] cpufreq_init_policy+0x8c/0x110
 [<ffffffff8145c9a0>] ? cpufreq_update_policy+0x1b0/0x1b0
 [<ffffffff8108fb99>] ? preempt_count_sub+0xb9/0x100
 [<ffffffff8145c6c6>] __cpufreq_add_dev+0x596/0x6b0
 [<ffffffffa016c608>] ? pcc_cpufreq_probe+0x4b4/0x4b4 [pcc_cpufreq]
 [<ffffffff8145c7ee>] cpufreq_add_dev+0xe/0x10
 [<ffffffff81408e81>] subsys_interface_register+0xc1/0xf0
 [<ffffffff8108fb99>] ? preempt_count_sub+0xb9/0x100
 [<ffffffff8145b3d7>] cpufreq_register_driver+0x117/0x2a0
 [<ffffffffa016c65d>] pcc_cpufreq_init+0x55/0x9f8 [pcc_cpufreq]
 [<ffffffffa016c608>] ? pcc_cpufreq_probe+0x4b4/0x4b4 [pcc_cpufreq]
 [<ffffffff81000298>] do_one_initcall+0xc8/0x1f0
 [<ffffffff811a731d>] ? __vunmap+0x9d/0x100
 [<ffffffff810eb9a0>] do_init_module+0x30/0x1b0
 [<ffffffff810edfa6>] load_module+0x686/0x710
 [<ffffffff810ebb20>] ? do_init_module+0x1b0/0x1b0
 [<ffffffff810ee1db>] SyS_init_module+0x9b/0xc0
 [<ffffffff8158f7a9>] system_call_fastpath+0x16/0x1b

Fixes: 8fec051eea (cpufreq: Convert existing drivers to use cpufreq_freq_transition_{begin|end})
Reported-and-tested-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: 3.15+ <stable@vger.kernel.org> # 3.15+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-09-29 15:35:50 +02:00
Viresh Kumar 8fec051eea cpufreq: Convert existing drivers to use cpufreq_freq_transition_{begin|end}
CPUFreq core has new infrastructure that would guarantee serialized calls to
target() or target_index() callbacks. These are called
cpufreq_freq_transition_begin() and cpufreq_freq_transition_end().

This patch converts existing drivers to use these new set of routines.

Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-03-26 16:41:41 +01:00
Viresh Kumar ab1b1c4e82 cpufreq: send new set of notification for transition failures
In the current code, if we fail during a frequency transition, we
simply send the POSTCHANGE notification with the old frequency. This
isn't enough.

One of the core users of these notifications is the code responsible
for keeping loops_per_jiffy aligned with frequency changes. And mostly
it is written as:

	if ((val == CPUFREQ_PRECHANGE  && freq->old < freq->new) ||
	    (val == CPUFREQ_POSTCHANGE && freq->old > freq->new)) {
		update-loops-per-jiffy...
	}

So, suppose we are changing to a higher frequency and failed during
transition, then following will happen:
- CPUFREQ_PRECHANGE notification with freq-new > freq-old
- CPUFREQ_POSTCHANGE notification with freq-new == freq-old

The first one will update loops_per_jiffy and second one will do
nothing. Even if we send the 2nd notification by exchanging values of
freq-new and old, some users of these notifications might get
unstable.

This can be fixed by simply calling cpufreq_notify_post_transition()
with error code and this routine will take care of sending
notifications in the correct order.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[rjw: Folded 3 patches into one, rebased unicore2 changes]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-01-06 01:43:44 +01:00
Rafael J. Wysocki 93658cb859 Merge branch 'pm-cpufreq'
* pm-cpufreq: (167 commits)
  cpufreq: create per policy rwsem instead of per CPU cpu_policy_rwsem
  intel_pstate: Add Baytrail support
  intel_pstate: Refactor driver to support CPUs with different MSR layouts
  cpufreq: Implement light weight ->target_index() routine
  PM / OPP: rename header to linux/pm_opp.h
  PM / OPP: rename data structures to dev_pm equivalents
  PM / OPP: rename functions to dev_pm_opp*
  cpufreq / governor: Remove fossil comment
  cpufreq: exynos4210: Use the common clock framework to set APLL clock rate
  cpufreq: exynos4x12: Use the common clock framework to set APLL clock rate
  cpufreq: Detect spurious invocations of update_policy_cpu()
  cpufreq: pmac64: enable cpufreq on iMac G5 (iSight) model
  cpufreq: pmac64: provide cpufreq transition latency for older G5 models
  cpufreq: pmac64: speed up frequency switch
  cpufreq: highbank-cpufreq: Enable Midway/ECX-2000
  exynos-cpufreq: fix false return check from "regulator_set_voltage"
  speedstep-centrino: Remove unnecessary braces
  acpi-cpufreq: Add comment under ACPI_ADR_SPACE_SYSTEM_IO case
  cpufreq: arm-big-little: use clk_get instead of clk_get_sys
  cpufreq: exynos: Show a list of available frequencies
  ...

Conflicts:
	drivers/devfreq/exynos/exynos5_bus.c
2013-10-28 01:29:34 +01:00
Viresh Kumar 6b67ca322d cpufreq: pcc: don't initialize part of policy set by core
Many common initializations of struct policy are moved to core now and hence
this driver doesn't need to do it. This patch removes such code.

Most recent of those changes is to call ->get() in the core after calling
->init().

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-16 00:50:31 +02:00
Viresh Kumar be49e3465f cpufreq: add new routine cpufreq_verify_within_cpu_limits()
Most of the users of cpufreq_verify_within_limits() calls it for
limiting with min/max from policy->cpuinfo. We can make that code
simple by introducing another routine which will do this for them
automatically.

This patch adds another routine cpufreq_verify_within_cpu_limits()
and updates others to use it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-16 00:50:23 +02:00
Zhang Rui 7ca9b57491 pcc_freq: convert acpi_get_handle() to acpi_has_method()
acpi_has_method() is a new ACPI API introduced to check
the existence of an ACPI control method.

It can be used to replace acpi_get_handle() in the case that
1. the calling function doesn't need the ACPI handle of the control method.
and
2. the calling function doesn't care the reason why the method is unavailable.

Convert acpi_get_handle() to acpi_has_method()
in drivers/cpufreq/pcc_freq.c in this patch.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-09-24 01:37:55 +02:00
Viresh Kumar adc97d6a73 cpufreq: Drop the owner field from struct cpufreq_driver
We don't need to set .owner = THIS_MODULE any more in cpufreq drivers
as this field isn't used any more by the cpufreq core.

This patch removes it and updates all dependent drivers accordingly.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-08-10 03:24:47 +02:00
Viresh Kumar f77f146599 cpufreq: pcc: call CPUFREQ_POSTCHANGE notfier in error cases
PRECHANGE and POSTCHANGE notifiers must be called in groups, i.e
either both should be called or both shouldn't be.

In case we have started PRECHANGE notifier and found an error, we
must call POSTCHANGE notifier with freqs.new = freqs.old to guarantee
that the sequence of calling notifiers is complete.

This patch fixes it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-06-24 13:26:39 +02:00
Viresh Kumar b43a7ffbf3 cpufreq: Notify all policy->cpus in cpufreq_notify_transition()
policy->cpus contains all online cpus that have single shared clock line. And
their frequencies are always updated together.

Many SMP system's cpufreq drivers take care of this in individual drivers but
the best place for this code is in cpufreq core.

This patch modifies cpufreq_notify_transition() to notify frequency change for
all cpus in policy->cpus and hence updates all users of this API.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-04-02 15:24:00 +02:00
Julia Lawall d06a8a4fe7 drivers/cpufreq/pcc-cpufreq.c: fix error return code
Convert a 0 error return code to a negative one, as returned elsewhere in the
function.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
identifier ret;
expression e,e1,e2,e3,e4,x;
@@

(
if (\(ret != 0\|ret < 0\) || ...) { ... return ...; }
|
ret = 0
)
... when != ret = e1
*x = \(kmalloc\|kzalloc\|kcalloc\|devm_kzalloc\|ioremap\|ioremap_nocache\|devm_ioremap\|devm_ioremap_nocache\)(...);
... when != x = e2
    when != ret = e3
*if (x == NULL || ...)
{
  ... when != ret = e4
*  return ret;
}
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-08-08 20:49:25 +02:00
Naga Chumbalkar e71f5cc402 drivers/cpufreq/pcc-cpufreq.c: avoid NULL pointer dereference
per_cpu(processors, n) can be NULL, resulting in:

  Loading CPUFreq modules[  437.661360] BUG: unable to handle kernel NULL pointer dereference at (null)
  IP: [<ffffffffa0434314>] pcc_cpufreq_cpu_init+0x74/0x220 [pcc_cpufreq]

It's better to avoid the oops by failing the driver, and allowing the
system to boot.

Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Len Brown <lenb@kernel.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-09-14 18:09:38 -07:00
Dave Jones bb0a56ecc4 [CPUFREQ] Move x86 drivers to drivers/cpufreq/
Signed-off-by: Dave Jones <davej@redhat.com>
2011-05-19 18:51:07 -04:00