linux.git/arch/powerpc/kernel/sysfs.c, branch v3.14

powerpc/pseries/cpuidle: smt-snooze-delay cleanup.

2014-01-29T06:02:24+00:00

smt-snooze-delay was designed to disable NAP state or delay the entry
to the NAP state prior to adoption of cpuidle framework. This
is per-cpu variable. With the coming of CPUIDLE framework,
states can be disabled on per-cpu basis using the cpuidle/enable
sysfs entry.

Also, with the coming of cpuidle driver each state's target residency
is per-driver unlike earlier which was per-device. Therefore,
the per-cpu sysfs smt-snooze-delay which decides the target residency
of the idle state on a particular cpu causes more confusion to the user
as we cannot have different smt-snooze-delay (target residency)
values for each cpu.

In the current code, smt-snooze-delay functionality is completely broken.
It makes sense to remove smt-snooze-delay from idle driver with the
coming of cpuidle framework.
However, sysfs files are retained as ppc64_util currently
utilises it. Once we fix ppc64_util, propose to clean
up the kernel code.

Signed-off-by: Deepthi Dharwar 
Signed-off-by: Benjamin Herrenschmidt

powerpc/85xx: add sysfs for pw20 state and altivec idle

2014-01-09T23:51:38+00:00

Add a sys interface to enable/diable pw20 state or altivec idle, and
control the wait entry time.

Enable/Disable interface:
    0, disable. 1, enable.
    /sys/devices/system/cpu/cpuX/pw20_state
    /sys/devices/system/cpu/cpuX/altivec_idle

Set wait time interface:(Nanosecond)
    /sys/devices/system/cpu/cpuX/pw20_wait_time
    /sys/devices/system/cpu/cpuX/altivec_idle_wait_time
Example: Base on TBfreq is 41MHZ.
    1~48(ns): TB[63]
    49~97(ns): TB[62]
    98~195(ns): TB[61]
    196~390(ns): TB[60]
    391~780(ns): TB[59]
    781~1560(ns): TB[58]
    ...

Signed-off-by: Wang Dongsheng 
[scottwood@freescale.com: change ifdef]
Signed-off-by: Scott Wood

powerpc/kernel/sysfs: Cleanup set up macros for PMC/non-PMC SPRs

2013-12-02T03:16:04+00:00

Currently PMC (Performance Monitor Counter) setup macros are used
for other SPRs. Since not all SPRs are PMC related, this patch
modifies the exisiting macro and uses it to setup both PMC and
non PMC SPRs accordingly.

Signed-off-by: Madhavan Srinivasan 
Acked-by: Olof Johansson 
Acked-by: Michael Ellerman 
Signed-off-by: Benjamin Herrenschmidt

powerpc/sysfs: Disable writing to PURR in guest mode

2013-10-03T07:22:53+00:00

arch/powerpc/kernel/sysfs.c exports PURR with write permission.
This may be valid for kernel in phyp mode. But writing to
the file in guest mode causes crash due to a priviledge violation

Signed-off-by: Madhavan Srinivasan 
Signed-off-by: Benjamin Herrenschmidt 
CC:

powerpc: Delete __cpuinit usage from all users

2013-07-01T01:10:36+00:00

The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications.  For example, the fix in
commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.

After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out.  Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.

This removes all the powerpc uses of the __cpuinit macros.  There
are no __CPUINIT users in assembly files in powerpc.

[1] https://lkml.org/lkml/2013/5/20/589

Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Josh Boyer 
Cc: Matt Porter 
Cc: Kumar Gala 
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Paul Gortmaker 
Signed-off-by: Benjamin Herrenschmidt

powerpc/topology: Fix spurr attribute permission

2013-05-06T05:02:40+00:00

We are registering the attribute with permission 0600 but it
doesn't have a store callback, which causes WARN_ON's during
boot. Fix the permission.

Signed-off-by: Benjamin Herrenschmidt

numa: convert static memory to dynamically allocated memory for per node device

2012-12-12T01:22:23+00:00

We use a static array to store struct node.  In many cases, we don't have
too many nodes, and some memory will be unused.  Convert it to per-device
dynamically allocated memory.

Signed-off-by: Wen Congyang 
Cc: David Rientjes 
Cc: Jiang Liu 
Cc: Minchan Kim 
Cc: KOSAKI Motohiro 
Cc: Yasuaki Ishimatsu 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cpuidle/powerpc: Fix smt_snooze_delay functionality.

2012-10-17T23:57:24+00:00

smt_snooze_delay was designed to  delay idle loop's nap entry
in the native idle code before it got  ported over to use as part of
the cpuidle framework.

A -ve value  assigned to smt_snooze_delay should result in
busy looping, in other words disabling the entry to nap state.

	- https://lists.ozlabs.org/pipermail/linuxppc-dev/2010-May/082450.html

This particular functionality can be achieved currently by
echo 1 > /sys/devices/system/cpu/cpu*/state1/disable
but it is broken when one assigns -ve value to  the smt_snooze_delay
variable either via sysfs entry or ppc64_cpu util.

This patch aims to fix this, by disabling nap state when smt_snooze_delay
variable is set to -ve value.

Signed-off-by: Deepthi Dharwar 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Keep thread.dscr and thread.dscr_inherit in sync

2012-09-05T06:05:21+00:00

When we update the DSCR either via emulation of mtspr(DSCR) or via
a change to dscr_default in sysfs we don't update thread.dscr.
We will eventually update it at context switch time but there is
a period where thread.dscr is incorrect.

If we fork at this point we will copy the old value of thread.dscr
into the child. To avoid this, always keep thread.dscr in sync with
reality.

This issue was found with the following testcase:

http://ozlabs.org/~anton/junkcode/dscr_inherit_test.c

Signed-off-by: Anton Blanchard 
Cc:  # 3.0+
Signed-off-by: Benjamin Herrenschmidt

powerpc: Update DSCR on all CPUs when writing sysfs dscr_default

2012-09-05T06:05:20+00:00

Writing to dscr_default in sysfs doesn't actually change the DSCR -
we rely on a context switch on each CPU to do the work. There is no
guarantee we will get a context switch in a reasonable amount of time
so fire off an IPI to force an immediate change.

This issue was found with the following test case:

http://ozlabs.org/~anton/junkcode/dscr_explicit_test.c

Signed-off-by: Anton Blanchard 
Cc:  # 3.0+
Signed-off-by: Benjamin Herrenschmidt