module.h: split out the EXPORT_SYMBOL into export.h

A lot of files pull in module.h when all they are really
looking for is the basic EXPORT_SYMBOL functionality. The
recent data from Ingo[1] shows that this is one of several
instances that has a significant impact on compile times,
and it should be targeted for factoring out (as done here).

Note that several commonly used header files in include/*
directly include <linux/module.h> themselves (some 34 of them!)
The most commonly used ones of these will have to be made
independent of module.h before the full benefit of this change
can be realized.

We also transition THIS_MODULE from module.h to export.h,
since there are lots of files with subsystem structs that
in turn will have a struct module *owner and only be doing:

	.owner = THIS_MODULE;

and absolutely nothing else modular. So, we also want to have
the THIS_MODULE definition present in the lightweight header.

[1] https://lkml.org/lkml/2011/5/23/76

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
lib: reduce the use of module.h wherever possible

For files only using THIS_MODULE and/or EXPORT_SYMBOL, map
them onto including export.h -- or if the file isn't even
using those, then just delete the include.  Fix up any implicit
include dependencies that were being masked by module.h along
the way.

Change-Id: I44d87b4e6ef5a8ee7a2eeec09bace97045513d49
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
cpufreq: expose a cpufreq_quick_get_max routine

This allows drivers and other code to get the max reported CPU frequency.
Initial use is for scaling ring frequency with GPU frequency in the i915
driver.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Keith Packard <keithp@keithp.com>
provide disable_cpufreq() function to disable the API.

useful for disabling cpufreq altogether. The cpu frequency
scaling drivers and cpu frequency governors will fail to register.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Dave Jones <davej@redhat.com>
cpufreq: Add cpu utilization statistics to aid decisions made by userspace.

Understanding system load as seen by cpufreq can help userspace
algorithms make better decisions to improve system responsiveness.
One such example would be the MP decision algorithm which mines
various system info to make decisions on hotplugging in/out
the additional cores.

Change-Id: I277db7e1a7803a3822b61e7befa25131487cfe17
Signed-off-by: Anitha Anand <anithas@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
cpufreq: Make the "scaling_governor" sysfs node pollable

A userspace module programs different qos-rules depending on the
governor running in the system. Make the governor node
pollable, so that the userspace module can be triggered when
the value of the governor changes.

change-Id: Ic89c77c7d16b0f8954d59a211612e9a8e98a2c28
Signed-off-by: Amar Singhal <asinghal@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
cpufreq: Save and restore min and max frequencies

In addition to restoring the previous governor after hotplug, restore
policy min and max frequencies.

CRs-fixed: 277482
Change-Id: I0d29281cecf4bd14ede06cd97d7bd3bffd0652c0
Signed-off-by: Praveen Chidambaram <pchidamb@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
cpufreq: make the "scaling_cur_freq" sysfs entry pollable

Wakeup userspace poll on change of cpu frequency. The userspace
may then take action to change the power/performance
characteristics of the device.

Change-Id: I3030b22084fe7e0143b978a198ddcc579e7d6e83
Signed-off-by: Amar Singhal <asinghal@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
cpufreq: Retain only online cpus in managed_policy->cpus

cpufreq's handling of cpu online event can incorrectly initialize
managed_policy->cpus to include offline cpus. This causes cpufreq
governors to include offline cpus in their idle time computation, which
causes frequency to shoot up beyond normal levels (on systems where 2 or
more cpus need to be synchronized wrt frequency change).

This frequency shootup was not seen prior to commit 21111be8 which
changed idle time accounting for offline cpus. Prior to commit 21111be8,
idle time statistics for offline cpus would include their offline time
as well. Post commit 21111be8, offline time is not included in a cpu's
idle time statistics.

As a result, ondemand (or other cpufreq) governors would see unchanged
idle time for offline cpus, causing them to interpret those (offline)
cpus as 100% busy, which is wrong.

This patch fixes the issue by modifying cpufreq's hotplug handling to
retain only online cpus in managed_policy->cpus field. cpufreq governors
would then skip such offline cpus from idle time calculations.

Change-Id: Id2eba8c0ec3367609369b2e42a4e1386ff2e7ab5
Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>
msm: cpufreq: Only apply driver limits for scaling_min/max_freq writes

When new values are written to scaling_min/max_freq sysfs files, the
current code applies all the limits imposed by various ADJUST and
INCOMPATIBLE notifiers handlers before storing them.

When the ADJUST and/or INCOMPATIBLE notifiers change their limits
frequently, this behavior makes it almost impossible for a
user/userspace process to store the scaling_min/max_freq limits
that go beyond the instantaneous limits imposed by the notifiers.
Since these sysfs nodes are typically meant to set limits that need
to be enforced for the foreseeable future, this is not a very user
friendly behavior.

So, change the behavior to only apply limits that are enforced by
the cpufreq driver. Typically, these are just the absolute limits
of the HW and don't change very often.

Change-Id: I1ccfaa2d1ee4ea595f882485d359dbdb407a0176
Signed-off-by: Deepak Katragadda <dkatraga@codeaurora.org>
cpufreq: Manage only online cpus

cpufreq core doesn't manage offline cpus and if driver->init() has returned
mask including offline cpus, it may result in unwanted behavior by cpufreq core
or governors.

We need to get only online cpus in this mask. There are two places to fix this
mask, cpufreq core and cpufreq driver. It makes sense to do this at common place
and hence is done in core.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpufreq: Avoid calling cpufreq driver's target() routine if target_freq == policy->cur

Avoid calling cpufreq driver's target() routine if new frequency is same as
policies current frequency.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpufreq: Save user policy min/max instead of policy min/max during hotplug

When a CPU is hotplugged off, various fields of the policy are saved so
that they can be restored when the CPU is hotplugged back in.

The existing code saves the policy min/max field during hotplug remove and
restores it into user policy min/max during hotplug add. This results in
the loss of the user policy min/max values across a hotplug remove/add.

Fix it by saving the user policy min/max instead of policy min/max during
hotplug remove. During a hotplug add, after user policy min/max is
restored, the policy min/max is already recomputed. So, there's no risk of
going beyound any limits imposed by the CPUFREQ_ADJUST/INCOMPATIBLE
notifiers.

Change-Id: Ib8e09fa324c1f80f095c5754b5dcf2685e8e4a66
Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
cpufreq: Fix policy getting stuck when user & kernel min/max don't overlap

Every __cpufreq_set_policy starts with checking the new policy min/max has
some overlap with the current policy min/max. This works out fine until we
end up with the policy min/max being set to a range that doesn't overlap
with the user policy min/max. Once we get into this situation, the check at
the start of __cpufreq_set_policy fails and prevents us from getting out of
this state.

This only happens when one of the CPUFREQ_ADJUST/CPUFREQ_INCOMPATIBLE
notifiers called inside __cpufreq_set_policy pick a min/max outside the
range of user policy min/max.

The real intent of the check at the start of __cpufreq_set_policy is to
make sure userspace can't set user policy min > user policy max. Since
__cpufreq_set_policy always gets called only with current user policy
min/max except when the actual user space policy min/max is changed, we can
fix the issue by simply checking the new policy min/max against current
user policy min/max.

Change-Id: Iaac805825e64d7985c41fb9052bd96baacdf3d6f
Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
Signed-off-by: Ajay Dudani <adudani@codeaurora.org>
(cherry picked from commit 9decaa70a478ef26bfca840febe6296493a249d9)
fs: exfat: fix compilation on all linux versions below 3.15

not supported yet even in mainline release

Change-Id: Ic6c4f44fc6c613945a746d27b9f639515ba0f593
defconfig: various changes

- disable min/max freq limit
- enable zram, swap and ksm
- disable shrm verification, samsung composite and mtp
- hardcode toolchain
- set panic timeout to 5 to allow better debugging of oops

Change-Id: I073afbaf877cf35db44ea3eb1e712f290744f50b
drivers: fix kernel section mismatches

Change-Id: I4bd289d976c3dd852f1c79675a62428665bc0da0
cpufreq: Fix sysfs deadlock with concurrent hotplug/frequency switch

Running one program that continuously hotplugs and replugs a cpu
concurrently with another program that continuously writes to the
scaling_setspeed node eventually deadlocks with:

=============================================
[ INFO: possible recursive locking detected ]
3.4.0 #37 Tainted: G        W
---------------------------------------------
filemonkey/122 is trying to acquire lock:
 (s_active#13){++++.+}, at: [<c01a3d28>] sysfs_remove_dir+0x9c/0xb4

but task is already holding lock:
 (s_active#13){++++.+}, at: [<c01a22f0>] sysfs_write_file+0xe8/0x140

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(s_active#13);
  lock(s_active#13);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

2 locks held by filemonkey/122:
 #0:  (&buffer->mutex){+.+.+.}, at: [<c01a2230>] sysfs_write_file+0x28/0x140
 #1:  (s_active#13){++++.+}, at: [<c01a22f0>] sysfs_write_file+0xe8/0x140

stack backtrace:
[<c0014fcc>] (unwind_backtrace+0x0/0x120) from [<c00ca600>] (validate_chain+0x6f8/0x1054)
[<c00ca600>] (validate_chain+0x6f8/0x1054) from [<c00cb778>] (__lock_acquire+0x81c/0x8d8)
[<c00cb778>] (__lock_acquire+0x81c/0x8d8) from [<c00cb9c0>] (lock_acquire+0x18c/0x1e8)
[<c00cb9c0>] (lock_acquire+0x18c/0x1e8) from [<c01a3ba8>] (sysfs_addrm_finish+0xd0/0x180)
[<c01a3ba8>] (sysfs_addrm_finish+0xd0/0x180) from [<c01a3d28>] (sysfs_remove_dir+0x9c/0xb4)
[<c01a3d28>] (sysfs_remove_dir+0x9c/0xb4) from [<c02d0e5c>] (kobject_del+0x10/0x38)
[<c02d0e5c>] (kobject_del+0x10/0x38) from [<c02d0f74>] (kobject_release+0xf0/0x194)
[<c02d0f74>] (kobject_release+0xf0/0x194) from [<c0565a98>] (cpufreq_cpu_put+0xc/0x24)
[<c0565a98>] (cpufreq_cpu_put+0xc/0x24) from [<c05683f0>] (store+0x6c/0x74)
[<c05683f0>] (store+0x6c/0x74) from [<c01a2314>] (sysfs_write_file+0x10c/0x140)
[<c01a2314>] (sysfs_write_file+0x10c/0x140) from [<c014af44>] (vfs_write+0xb0/0x128)
[<c014af44>] (vfs_write+0xb0/0x128) from [<c014b06c>] (sys_write+0x3c/0x68)
[<c014b06c>] (sys_write+0x3c/0x68) from [<c000e0e0>] (ret_fast_syscall+0x0/0x3c)

This is because store() in cpufreq.c indirectly calls
kobject_get() via cpufreq_cpu_get() and is the last one to call
kobject_put() via cpufreq_cpu_put(). Sysfs code should not call
kobject_get() or kobject_put() directly (see the comment around
sysfs_schedule_callback() for more information).

Fix this deadlock by introducing two new functions:

	struct cpufreq_policy *cpufreq_cpu_get_sysfs(unsigned int cpu)
	void cpufreq_cpu_put_sysfs(struct cpufreq_policy *data)

which do the same thing as cpufreq_cpu_{get,put}() but don't call
kobject functions.

To easily trigger this deadlock you can insert an msleep() with a
reasonably large value right after the fail label at the bottom
of the store() function in cpufreq.c and then write
scaling_setspeed in one task and offline the cpu in another. The
first task will hang and be detected by the hung task detector.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
cpufreq: return early from __cpufreq_driver_getavg()

There is no need to do cpufreq_get_cpu() and cpufreq_put_cpu() for drivers that
don't support getavg() routine.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpufreq: Make sure target freq is within limits

__cpufreq_driver_target() must not pass target frequency beyond the
limits of current policy.

Today most of cpufreq platform drivers are doing this check in their
target routines. Why not move it to __cpufreq_driver_target()?

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>