linux-toradex.git/drivers/cpufreq, branch v2.6.32.33

revert "[CPUFREQ] remove rwsem lock from CPUFREQ_GOV_STOP call (second call site)"

2010-08-02T17:21:25+00:00

commit accd846698439ba18250e8fd5681af280446b853 upstream.

395913d0b1db37092ea3d9d69b832183b1dd84c5 ("[CPUFREQ] remove rwsem lock
from CPUFREQ_GOV_STOP call (second call site)") is not needed, because
there is no rwsem lock in cpufreq_ondemand and cpufreq_conservative
anymore.  Lock should not be released until the work done.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=1594

Signed-off-by: Andrej Gelenberg 
Cc: Mathieu Desnoyers 
Cc: Venkatesh Pallipadi 
Signed-off-by: Andrew Morton 
Acked-by: Mathieu Desnoyers 
Signed-off-by: Dave Jones 
Signed-off-by: Greg Kroah-Hartman

[CPUFREQ] Fix stale cpufreq_cpu_governor pointer

2009-11-18T04:15:04+00:00

Dave,

Attached is an update of my patch against the cpufreq fixes branch.

Before applying the patch I compiled and booted the tree to see if the panic
was still there -- to my surprise it was not.  This is because of the conversion
of cpufreq_cpu_governor to a char[].

While the panic is kaput, the problem of stale data continues and my patch is
still valid.  It is possible to end up with the wrong governor after hotplug
events because CPUFREQ_DEFAULT_GOVERNOR is statically linked to a default,
while the cpu siblings may have had a different governor assigned by a user.

ie) the patch is still needed in order to keep the governors assigned
properly when hotplugging devices

Signed-off-by: Prarit Bhargava 
Signed-off-by: Dave Jones

[CPUFREQ] Resolve time unit thinko in ondemand/conservative govs

2009-11-18T04:15:04+00:00

ondemand and conservative governors are messing up time units in the
code path where NO_HZ is not enabled and ignore_nice is set. The walltime
idletime stored is in jiffies and nice time calculation is happening in
microseconds.

The problem was reported and diagnosed by Alexander here.
http://marc.info/?l=linux-kernel&m=125752550404513&w=2

The patch below fixes this thinko.

Reported-by: Alexander Miller 
Tested-by: Alexander Miller 
Signed-off-by: Venkatesh Pallipadi 
Signed-off-by: Dave Jones

[CPUFREQ] Fix use after free on governor restore

2009-11-18T04:15:04+00:00

Currently on governer backup/restore path we storing governor's pointer.
This is wrong because one may unload governor's module after cpu goes
offline. As result use-after-free will take place on restored cpu.
It is not easy to exploit this bug, but still we have to close this
issue ASAP. Issue was introduced by following commit
084f34939424161669467c19280dbcf637730314

##TESTCASE##
#!/bin/sh -x
modprobe acpi_cpufreq
# Any non default governor, in may case it is "ondemand"
modprobe cpufreq_ondemand
echo ondemand > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
rmmod acpi_cpufreq
rmmod cpufreq_ondemand
modprobe acpi_cpufreq  # << use-after-free here.

Signed-off-by: Dmitry Monakhov 
Signed-off-by: Dave Jones

Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq

2009-09-18T16:16:57+00:00

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq:
  [CPUFREQ] Fix NULL ptr regression in powernow-k8
  [CPUFREQ] Create a blacklist for processors that should not load the acpi-cpufreq module.
  [CPUFREQ] Powernow-k8: Enable more than 2 low P-states
  [CPUFREQ] remove rwsem lock from CPUFREQ_GOV_STOP call (second call site)
  [CPUFREQ] ondemand - Use global sysfs dir for tuning settings
  [CPUFREQ] Introduce global, not per core: /sys/devices/system/cpu/cpufreq
  [CPUFREQ] Bail out of cpufreq_add_dev if the link for a managed CPU got created
  [CPUFREQ] Factor out policy setting from cpufreq_add_dev
  [CPUFREQ] Factor out interface creation from cpufreq_add_dev
  [CPUFREQ] Factor out symlink creation from cpufreq_add_dev
  [CPUFREQ] cleanup up -ENOMEM handling in cpufreq_add_dev
  [CPUFREQ] Reduce scope of cpu_sys_dev in cpufreq_add_dev
  [CPUFREQ] update Doc for cpuinfo_cur_freq and scaling_cur_freq

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu

2009-09-15T16:39:44+00:00

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (46 commits)
  powerpc64: convert to dynamic percpu allocator
  sparc64: use embedding percpu first chunk allocator
  percpu: kill lpage first chunk allocator
  x86,percpu: use embedding for 64bit NUMA and page for 32bit NUMA
  percpu: update embedding first chunk allocator to handle sparse units
  percpu: use group information to allocate vmap areas sparsely
  vmalloc: implement pcpu_get_vm_areas()
  vmalloc: separate out insert_vmalloc_vm()
  percpu: add chunk->base_addr
  percpu: add pcpu_unit_offsets[]
  percpu: introduce pcpu_alloc_info and pcpu_group_info
  percpu: move pcpu_lpage_build_unit_map() and pcpul_lpage_dump_cfg() upward
  percpu: add @align to pcpu_fc_alloc_fn_t
  percpu: make @dyn_size mandatory for pcpu_setup_first_chunk()
  percpu: drop @static_size from first chunk allocators
  percpu: generalize first chunk allocator selection
  percpu: build first chunk allocators selectively
  percpu: rename 4k first chunk allocator to page
  percpu: improve boot messages
  percpu: fix pcpu_reclaim() locking
  ...

Fix trivial conflict as by Tejun Heo in kernel/sched.c

[CPUFREQ] remove rwsem lock from CPUFREQ_GOV_STOP call (second call site)

2009-09-01T16:45:18+00:00

remove rwsem lock from CPUFREQ_GOV_STOP call (second call site)

commit	42a06f2166f2f6f7bf04f32b4e823eacdceafdc9

Missed a call site for CPUFREQ_GOV_STOP to remove the rwlock taken around the
teardown. To make a long story short, the rwlock write-lock causes a circular
dependency with cancel_delayed_work_sync(), because the timer handler takes the
read lock.

Note that all callers to __cpufreq_set_policy are taking the rwsem. All sysfs
callers (writers) hold the write rwsem at the earliest sysfs calling stage.

However, the rwlock write-lock is not needed upon governor stop.

Signed-off-by: Mathieu Desnoyers 
Acked-by: Venkatesh Pallipadi 
CC: rjw@sisk.pl
CC: mingo@elte.hu
CC: Shaohua Li 
CC: Pekka Enberg 
CC: Dave Young 
CC: "Rafael J. Wysocki" 
CC: Rusty Russell 
CC: trenn@suse.de
CC: sven.wegener@stealer.net
CC: cpufreq@vger.kernel.org
Signed-off-by: Dave Jones

[CPUFREQ] ondemand - Use global sysfs dir for tuning settings

2009-09-01T16:45:18+00:00

Ondemand has only global variables for userspace tunings via sysfs.
But they were exposed per CPU which wrongly implies to the user that
his settings are applied per cpu. Also locking sysfs against concurrent
access won't be necessary anymore after deprecation time.

This means the ondemand config dir is moved:
/sys/devices/system/cpu/cpu*/cpufreq/ondemand ->
     /sys/devices/system/cpu/cpufreq/ondemand

The old files will still exist, but reading or writing to them will
result in one (printk_once) deprecation msg to syslog per file.

Signed-off-by: Thomas Renninger 
Signed-off-by: Dave Jones

[CPUFREQ] Introduce global, not per core: /sys/devices/system/cpu/cpufreq

2009-09-01T16:45:14+00:00

Currently everything in the cpufreq layer is per core based.
This does not reflect reality, for example ondemand on conservative
governors have global sysfs variables.

Introduce a global cpufreq directory and add the kobject to the governor
struct, so that governors can easily access it.
The directory is initialized in the cpufreq_core_init initcall and thus will
always be created if cpufreq is compiled in, even if no cpufreq driver is
active later.

Signed-off-by: Thomas Renninger 
Signed-off-by: Dave Jones

[CPUFREQ] Bail out of cpufreq_add_dev if the link for a managed CPU got created

2009-09-01T16:45:14+00:00

Doing:
echo 0 >cpu1/online
echo 1 >cpu1/online

on a managed CPU will result in:
Jul 22 15:15:37 linux kernel: [   80.013864] WARNING: at fs/sysfs/dir.c:487 sysfs_add_one+0xcf/0xe6()
Jul 22 15:15:37 linux kernel: [   80.013866] Hardware name: To Be Filled By O.E.M.
Jul 22 15:15:37 linux kernel: [   80.013868] sysfs: cannot create duplicate filename '/devices/system/cpu/cpu1/cpufreq'
Jul 22 15:15:37 linux kernel: [   80.013870] Modules linked in: powernow_k8
Jul 22 15:15:37 linux kernel: [   80.013874] Pid: 5750, comm: bash Not tainted 2.6.31-rc2 #40
Jul 22 15:15:37 linux kernel: [   80.013876] Call Trace:
Jul 22 15:15:37 linux kernel: [   80.013879]  [] ? sysfs_add_one+0xcf/0xe6
Jul 22 15:15:37 linux kernel: [   80.013884]  [] warn_slowpath_common+0x77/0xa4
Jul 22 15:15:37 linux kernel: [   80.013888]  [] warn_slowpath_fmt+0x3c/0x3e
Jul 22 15:15:37 linux kernel: [   80.013891]  [] sysfs_add_one+0xcf/0xe6
Jul 22 15:15:37 linux kernel: [   80.013894]  [] create_dir+0x58/0x87
Jul 22 15:15:37 linux kernel: [   80.013898]  [] sysfs_create_dir+0x38/0x4f
Jul 22 15:15:37 linux kernel: [   80.013902]  [] kobject_add_internal+0x11f/0x1de
Jul 22 15:15:37 linux kernel: [   80.013905]  [] kobject_add_varg+0x41/0x4e
Jul 22 15:15:37 linux kernel: [   80.013908]  [] kobject_init_and_add+0x4c/0x57
Jul 22 15:15:37 linux kernel: [   80.013913]  [] ? mark_lock+0x22/0x228
Jul 22 15:15:37 linux kernel: [   80.013918]  [] cpufreq_add_dev_interface+0x40/0x1e4
...

This bug slipped in by git commit:
150b06f7f223cfd0f808737a5243cceca8ea47fa

When splitting up cpufreq_add_dev, the whole cpufreq_add_dev function
is not left anymore, only cpufreq_add_dev_policy.
This patch should reconstruct the identical functionality again as it
was before the split.

CC: Venkatesh Pallipadi 
Signed-off-by: Thomas Renninger 
Signed-off-by: Dave Jones