Today we have:
config PPC_BOOK3S_32
bool "512x/52xx/6xx/7xx/74xx/82xx/83xx/86xx"
[depends on PPC32 within a choice]
config PPC_BOOK3S
def_bool y
depends on PPC_BOOK3S_32 || PPC_BOOK3S_64
config 6xx
def_bool y
depends on PPC32 && PPC_BOOK3S
6xx is therefore redundant with PPC_BOOK3S_32.
In order to make the code clearer, lets use preferably PPC_BOOK3S_32.
This will allow to remove CONFIG_6xx in a later patch.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Bring in yet another series that touches KVM code, and might need to
be merged into the kvm-ppc branch to resolve conflicts.
This required some changes in pnv_power9_force_smt4_catch/release()
due to the paca array becomming an array of pointers.
Move this into the early setup code, and don't iterate over CPU masks.
We don't want to call into sysfs so early from setup, and a future patch
won't initialize CPU masks by the time this is called.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Fold in incremental fix from Nick for DSCR handling]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Change the paca array into an array of pointers to pacas. Allocate
pacas individually.
This allows flexibility in where the PACAs are allocated. Future work
will allocate them node-local. Platforms that don't have address limits
on PACAs would be able to defer PACA allocations until later in boot
rather than allocate all possible ones up-front then freeing unused.
This is slightly more overhead (one additional indirection) for cross
CPU paca references, but those aren't too common.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The TSCR can only be accessed in hypervisor mode.
Fixes: 88b5e12eeb11 ("powerpc: Expose TSCR via sysfs")
Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The thread switch control register (TSCR) is a per core register
that configures how the CPU shares resources between SMT threads.
Exposing it via sysfs allows us to tune it at run time.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Take the DSCR value set by firmware as the dscr_default value,
rather than zero.
POWER9 recommends DSCR default to a non-zero value.
Signed-off-by: From: Nicholas Piggin <npiggin@gmail.com>
[mpe: Make record_spr_defaults() __init]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The entire body of unregister_cpu_online() is inside an #ifdef
CONFIG_HOTPLUG_CPU block. This is ugly and means we create an empty function
when hotplug is disabled for no reason.
Instead move the #ifdef out of the function body and define the function to be
NULL in the else case. This means we'll pass NULL to cpuhp_setup_state(), but
that's fine because it accepts NULL to mean there is no teardown callback, which
is exactly what we want.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
For CPUs present at boot each logical CPU acquires a reference to the
associated device node of the core. This happens in register_cpu() which
is called by topology_init(). The result of this is that we end up with
a reference held by each thread of the core. However, these references
are never freed if the CPU core is DLPAR removed.
This patch fixes the reference leaks by acquiring and releasing the references
in the CPU hotplug callbacks un/register_cpu_online(). With this patch symmetric
reference counting is observed with both CPUs present at boot, and those DLPAR
added after boot.
Fixes: f86e4718f2 ("driver/core: cpu: initialize of_node in cpu's device struture")
Cc: stable@vger.kernel.org # v3.12+
Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.
The previous convention of keeping the files around until the CPU is dead
has not been preserved as there is no point to keep them available when the
cpu is going down. This makes the hotplug call symmetric.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: rt@linuxtronix.de
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/20161117183541.8588-17-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This is just a smattering of things picked up by sparse that should
be made static.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patch adds some in-code documentation to the DSCR related code to
make it more readable without having any functional change to it.
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This still has not been merged and now powerpc is the only arch that does
not have this change. Sorry about missing linuxppc-dev before.
V2->V2
- Fix up to work against 3.18-rc1
__get_cpu_var() is used for multiple purposes in the kernel source. One of
them is address calculation via the form &__get_cpu_var(x). This calculates
the address for the instance of the percpu variable of the current processor
based on an offset.
Other use cases are for storing and retrieving data from the current
processors percpu area. __get_cpu_var() can be used as an lvalue when
writing data or on the right side of an assignment.
__get_cpu_var() is defined as :
__get_cpu_var() always only does an address determination. However, store
and retrieve operations could use a segment prefix (or global register on
other platforms) to avoid the address calculation.
this_cpu_write() and this_cpu_read() can directly take an offset into a
percpu area and use optimized assembly code to read and write per cpu
variables.
This patch converts __get_cpu_var into either an explicit address
calculation using this_cpu_ptr() or into a use of this_cpu operations that
use the offset. Thereby address calculations are avoided and less registers
are used when code is generated.
At the end of the patch set all uses of __get_cpu_var have been removed so
the macro is removed too.
The patch set includes passes over all arches as well. Once these operations
are used throughout then specialized macros can be defined in non -x86
arches as well in order to optimize per cpu access by f.e. using a global
register that may be set to the per cpu base.
Transformations done to __get_cpu_var()
1. Determine the address of the percpu instance of the current processor.
DEFINE_PER_CPU(int, y);
int *x = &__get_cpu_var(y);
Converts to
int *x = this_cpu_ptr(&y);
2. Same as #1 but this time an array structure is involved.
DEFINE_PER_CPU(int, y[20]);
int *x = __get_cpu_var(y);
Converts to
int *x = this_cpu_ptr(y);
3. Retrieve the content of the current processors instance of a per cpu
variable.
DEFINE_PER_CPU(int, y);
int x = __get_cpu_var(y)
Converts to
int x = __this_cpu_read(y);
4. Retrieve the content of a percpu struct
DEFINE_PER_CPU(struct mystruct, y);
struct mystruct x = __get_cpu_var(y);
Converts to
memcpy(&x, this_cpu_ptr(&y), sizeof(x));
5. Assignment to a per cpu variable
DEFINE_PER_CPU(int, y)
__get_cpu_var(y) = x;
Converts to
__this_cpu_write(y, x);
6. Increment/Decrement etc of a per cpu variable
DEFINE_PER_CPU(int, y);
__get_cpu_var(y)++
Converts to
__this_cpu_inc(y)
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
Signed-off-by: Christoph Lameter <cl@linux.com>
[mpe: Fix build errors caused by set/or_softirq_pending(), and rework
assignment in __set_breakpoint() to use memcpy().]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Since commit "efcac65 powerpc: Per process DSCR + some fixes (try#4)"
it is no longer possible to set the DSCR on a per-CPU basis.
The old behaviour was to minipulate the DSCR SPR directly but this is no
longer sufficient: the value is quickly overwritten by context switching.
This patch stores the per-CPU DSCR value in a kernel variable rather than
directly in the SPR and it is used whenever a process has not set the DSCR
itself. The sysfs interface (/sys/devices/system/cpu/cpuN/dscr) is unchanged.
Writes to the old global default (/sys/devices/system/cpu/dscr_default)
now set all of the per-CPU values and reads return the last written value.
The new per-CPU default is added to the paca_struct and is used everywhere
outside of sysfs.c instead of the old global default.
Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Split the __SYSFS_SPRSETUP macro into two parts so that registers requiring
custom read and write functions can use common code for their show and store
functions.
Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subsystems that want to register CPU hotplug callbacks, as well as perform
initialization for the CPUs that are already online, often do it as shown
below:
get_online_cpus();
for_each_online_cpu(cpu)
init_cpu(cpu);
register_cpu_notifier(&foobar_cpu_notifier);
put_online_cpus();
This is wrong, since it is prone to ABBA deadlocks involving the
cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently
with CPU hotplug operations).
Instead, the correct and race-free way of performing the callback
registration is:
cpu_notifier_register_begin();
for_each_online_cpu(cpu)
init_cpu(cpu);
/* Note the use of the double underscored version of the API */
__register_cpu_notifier(&foobar_cpu_notifier);
cpu_notifier_register_done();
Fix the sysfs code in powerpc by using this latter form of callback
registration.
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Olof Johansson <olof@lixom.net>
Cc: Wang Dongsheng <dongsheng.wang@freescale.com>
Cc: Ingo Molnar <mingo@kernel.org>
Acked-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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 <deepthi@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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 <dongsheng.wang@freescale.com>
[scottwood@freescale.com: change ifdef]
Signed-off-by: Scott Wood <scottwood@freescale.com>
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 <maddy@linux.vnet.ibm.com>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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 <maddy@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: <stable@vger.kernel.org>
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 <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Josh Boyer <jwboyer@gmail.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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 <benh@kernel.crashing.org>
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 <wency@cn.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Jiang Liu <liuj97@gmail.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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 <deepthi@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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 <anton@samba.org>
Cc: <stable@kernel.org> # 3.0+
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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 <anton@samba.org>
Cc: <stable@kernel.org> # 3.0+
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Disintegrate asm/system.h for PowerPC.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
cc: linuxppc-dev@lists.ozlabs.org
This is no longer selectable, so just remove all the dependent code.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (73 commits)
arm: fix up some samsung merge sysdev conversion problems
firmware: Fix an oops on reading fw_priv->fw in sysfs loading file
Drivers:hv: Fix a bug in vmbus_driver_unregister()
driver core: remove __must_check from device_create_file
debugfs: add missing #ifdef HAS_IOMEM
arm: time.h: remove device.h #include
driver-core: remove sysdev.h usage.
clockevents: remove sysdev.h
arm: convert sysdev_class to a regular subsystem
arm: leds: convert sysdev_class to a regular subsystem
kobject: remove kset_find_obj_hinted()
m86k: gpio - convert sysdev_class to a regular subsystem
mips: txx9_sram - convert sysdev_class to a regular subsystem
mips: 7segled - convert sysdev_class to a regular subsystem
sh: dma - convert sysdev_class to a regular subsystem
sh: intc - convert sysdev_class to a regular subsystem
power: suspend - convert sysdev_class to a regular subsystem
power: qe_ic - convert sysdev_class to a regular subsystem
power: cmm - convert sysdev_class to a regular subsystem
s390: time - convert sysdev_class to a regular subsystem
...
Fix up conflicts with 'struct sysdev' removal from various platform
drivers that got changed:
- arch/arm/mach-exynos/cpu.c
- arch/arm/mach-exynos/irq-eint.c
- arch/arm/mach-s3c64xx/common.c
- arch/arm/mach-s3c64xx/cpu.c
- arch/arm/mach-s5p64x0/cpu.c
- arch/arm/mach-s5pv210/common.c
- arch/arm/plat-samsung/include/plat/cpu.h
- arch/powerpc/kernel/sysfs.c
and fix up cpu_is_hotpluggable() as per Greg in include/linux/cpu.h
This moves the 'memory sysdev_class' over to a regular 'memory' subsystem
and converts the devices to regular devices. The sysdev drivers are
implemented as subsystem interfaces now.
After all sysdev classes are ported to regular driver core entities, the
sysdev implementation will be entirely removed from the kernel.
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This moves the 'cpu sysdev_class' over to a regular 'cpu' subsystem
and converts the devices to regular devices. The sysdev drivers are
implemented as subsystem interfaces now.
After all sysdev classes are ported to regular driver core entities, the
sysdev implementation will be entirely removed from the kernel.
Userspace relies on events and generic sysfs subsystem infrastructure
from sysdev devices, which are made available with this conversion.
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Borislav Petkov <bp@amd64.org>
Cc: Tigran Aivazian <tigran@aivazian.fsnet.co.uk>
Cc: Len Brown <lenb@kernel.org>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch implements a back-end cpuidle driver for pSeries
based on pseries_dedicated_idle_loop and pseries_shared_idle_loop
routines. The driver is built only if CONFIG_CPU_IDLE is set. This
cpuidle driver uses global registration of idle states and
not per-cpu.
Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: Trinabh Gupta <g.trinabh@gmail.com>
Signed-off-by: Arun R Bharadwaj <arun.r.bharadwaj@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
On Fri, Nov 11, 2011 at 10:17:55AM +0530, Ananth N Mavinakayanahalli wrote:
> >
> > At this rate we're going to end up with no bits left for CPU features
> > way too quickly... Especially for something we only care about once at
> > boot time.
> >
> > Wouldn't CPU_FTR_PPCAS_ARCH_V2 be a good enough test ?
>
> /me checks Cell manuals... yes, that test would be good enough. I will
> cook up a patch to use this.
Here it is...
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
All these files were including module.h just for the basic
EXPORT_SYMBOL infrastructure. We can shift them off to the
export.h header which is a way smaller footprint and thus
realize some compile time gains.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
The DSCR (aka Data Stream Control Register) is supported on some
server PowerPC chips and allow some control over the prefetch
of data streams.
This patch allows the value to be specified per thread by emulating
the corresponding mfspr and mtspr instructions. Children of such
threads inherit the value. Other threads use a default value that
can be specified in sysfs - /sys/devices/system/cpu/dscr_default.
If a thread starts with non default value in the sysfs entry,
all children threads inherit this non default value even if
the sysfs value is changed later.
Signed-off-by: Alexey Kardashevskiy <aik@au1.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Right now if we want to busy loop and not give up any time to the hypervisor
we put a very large value into smt_snooze_delay. This is sometimes useful
when running a single partition and you want to avoid any latencies due
to the hypervisor or CPU power state transitions. While this works, it's a bit
ugly - how big a number is enough now we have NO_HZ and can be idle for a very
long time.
The patch below makes smt_snooze_delay signed, and a negative value means loop
forever:
echo -1 > /sys/devices/system/cpu/cpu0/smt_snooze_delay
This change shouldn't affect the existing userspace tools (eg ppc64_cpu), but
I'm cc-ing Nathan just to be sure.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
I'm not sure why we have code for parsing an ibm,smt-snooze-delay OF
property. Since we have a smt-snooze-delay= boot option and we can
also set it at runtime via sysfs, it should be safe to get rid of
this code.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Version 3 of this patch is updated with documentation added to
Documentation/ABI. There are no changes to any of the C code from v2
of the patch.
In order to support kernel DLPAR of CPU resources we need to provide an
interface to add (probe) and remove (release) the resource from the system.
This patch Creates new generic probe and release sysfs files to facilitate
cpu probe/release. The probe/release interface provides for allowing each
arch to supply their own routines for implementing the backend of adding
and removing cpus to/from the system.
This also creates the powerpc specific stubs to handle the arch callouts
from writes to the sysfs files.
The creation and use of these files is regulated by the
CONFIG_ARCH_CPU_PROBE_RELEASE option so that only architectures that need the
capability will have the files created.
Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Currently there is a bug where if you use oprofile on a pSeries
machine, then use perf_counters, then use oprofile again, oprofile
will not work correctly; it will lose the PMU configuration the next
time the hypervisor does a partition context switch, and thereafter
won't count anything.
Maynard Johnson identified the sequence causing the problem:
- oprofile setup calls ppc_enable_pmcs(), which calls
pseries_lpar_enable_pmcs, which tells the hypervisor that we want
to use the PMU, and sets the "PMU in use" flag in the lppaca.
This flag tells the hypervisor whether it needs to save and restore
the PMU config.
- The perf_counter code sets and clears the "PMU in use" flag directly
as it context-switches the PMU between tasks, and leaves it clear
when it finishes.
- oprofile setup, called for a new oprofile run, calls ppc_enable_pmcs,
which does nothing because it has already been called. In particular
it doesn't set the "PMU in use" flag.
This fixes the problem by arranging for ppc_enable_pmcs to always set
the "PMU in use" flag. It makes the perf_counter code call
ppc_enable_pmcs also rather than calling the lower-level function
directly, and removes the setting of the "PMU in use" flag from
pseries_lpar_enable_pmcs, since that is now done in its caller.
This also removes the declaration of pasemi_enable_pmcs because it
isn't defined anywhere.
Reported-by: Maynard Johnson <mpjohn@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: <stable@kernel.org)
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Rusty's patch to change our sysfs access to various registers
to use smp_call_function_single() introduced a whole bunch of
warnings. This fixes them. This version also fixes an actual
bug in here where it did mtspr instead of mfspr when reading
the files
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Impact: performance improvement
This fixes 'powerpc: avoid cpumask games in arch/powerpc/kernel/sysfs.c'
which talked about using smp_call_function_single, but actually used
work_on_cpu (an older version of the patch).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The current code for providing processor cache information in sysfs
has the following deficiencies:
- several complex functions that are hard to understand
- implicit recursion (cache_desc_release -> kobject_put -> cache_desc_release)
- explicit recursion (create_cache_index_info)
- use of two per-cpu arrays when one would suffice
- duplication of work on systems where CPUs share cache
Also, when I looked at implementing support for a shared_cpu_map
attribute, it was pretty much impossible to handle hotplug without
checking every single online CPU's cache_desc list and fixing things
up... not that this is a hot path, but it would have introduced
O(n^2)-ish behavior during boot. Addressing this involved rethinking
the core data structures used, which didn't lend itself to an
incremental approach.
This implementation maintains a "forest" (potentially more than one
tree) of cache objects which reflects the system's cache topology.
Cache objects are instantiated as needed as CPUs come online. A
per-cpu array is used mainly for sysfs-related bookkeeping; the
objects in the array just point to the appropriate points in the
forest.
This maintains compatibility with the existing code and includes some
enhancements:
- Implement the shared_cpu_map attribute, which is essential for
enabling userspace to discover the system's overall cache topology.
- Use cache-block-size properties if cache-line-size is not available.
I chose to place this implementation in a new file since it would have
roughly doubled the size of sysfs.c, which is already kind of messy.
Signed-off-by: Nathan Lynch <ntl@pobox.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Using the common code means that more complete cache information will
provided in sysfs on platforms that don't use the l2-cache property
convention.
Signed-off-by: Nathan Lynch <ntl@pobox.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
attr_smt_snooze_delay is only defined for CONFIG_PPC64, so protect the
attribute removal with the same condition. This fixes this build error
on 32-bit SMP configurations:
/data/home/miltonm/next.git/arch/powerpc/kernel/sysfs.c: In function ‘unregister_cpu_online’:
/data/home/miltonm/next.git/arch/powerpc/kernel/sysfs.c:722: error: ‘attr_smt_snooze_delay’ undeclared (first use in this function)
/data/home/miltonm/next.git/arch/powerpc/kernel/sysfs.c:722: error: (Each undeclared identifier is reported only once
/data/home/miltonm/next.git/arch/powerpc/kernel/sysfs.c:722: error: for each function it appears in.)
Signed-off-by: Paul Mackerras <paulus@samba.org>
arch/powerpc/kernel/sysfs.c:197:7: warning: "CONFIG_6xx" is not defined
arch/powerpc/kernel/sysfs.c:141: warning: 'run_on_cpu' defined but not used
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
The file arch/powerpc/kernel/sysfs.c is currently only compiled for
64-bit kernels. It contain code to register CPU sysdevs in sysfs and
add various properties such as cache topology and raw access by root
to performance monitor counters (PMCs). A lot of that can be re-used
as is on 32-bits.
This makes the file be built for both, with appropriate ifdef'ing
for the few bits that are really 64-bit specific, and adds some
support for the raw PMCs for 75x and 74xx processors.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
When removing a directory, the sysfs core takes care of removing files
in the directory (see sysfs_remove_dir()). So when we are about to
delete a kobject (and thus cause its sysfs directory to be removed),
we don't have to explicitly remove the files attached to it, although
it's harmless to do so.
Signed-off-by: Nathan Lynch <ntl@pobox.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Collect cache information from the OF device tree and display it in
the cpu hierarchy in sysfs. This is intended to be compatible at the
userspace level with x86's implementation[1], hence some of the funny
attribute names. The arrangement of cache info is not immediately
intuitive, but (again) it's for compatibility's sake.
The cache attributes exposed are:
type (Data, Instruction, or Unified)
level (1, 2, 3...)
size
coherency_line_size
number_of_sets
ways_of_associativity
All of these can be derived on platforms that follow the OF PowerPC
Processor binding. The code "publishes" only those attributes for
which it is able to determine values; attributes for values which
cannot be determined are not created at all.
[1] arch/x86/kernel/cpu/intel_cacheinfo.c
BenH: Turned some printk's into pr_debug, added better NULL checking
in a couple of places.
Signed-off-by: Nathan Lynch <ntl@pobox.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
It is called only in cpu online paths.
(caught by CONFIG_DEBUG_SECTION_MISMATCH=y)
Signed-off-by: Nathan Lynch <ntl@pobox.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
A struct sysdev_attribute * parameter was added to the show routine by
commit 4a0b2b4dbe "sysdev: Pass the
attribute to the low level sysdev show/store function".
This eliminates a warning:
arch/powerpc/kernel/sysfs.c:538: warning: initialization from incompatible pointer type
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Christophe Leroy