Signed-off-by: Frans Pop <elendil@planet.nl>
Cc: linuxppc-dev@ozlabs.org
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The cede latency stuff is relatively new and we don't need to complain about
it not working on older firmware.
Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
String constants that are continued on subsequent lines with \
are not good.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The tb_total and purr_total values reported via the hcall_stats code
should be cumulative, rather than being replaced by the latest delta tb
or purr value.
Tested-by: Will Schmidt <will_schmidt@vnet.ibm.com>
Signed-off-by: Will Schmidt <will_schmidt@vnet.ibm.com>
Acked-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Recent U-Boot commit 5ccd29c3679b3669b0bde5c501c1aa0f325a7acb caused
the "cpu-release-addr" device tree property to contain the physical RAM
location that secondary cores were spinning at. Previously, the
"cpu-release-addr" property contained a value referencing the boot page
translation address range of 0xfffffxxx, which then indirectly accessed
RAM.
The "cpu-release-addr" is currently ioremapped and the secondary cores
kicked. However, due to the recent change in "cpu-release-addr", it
sometimes points to a memory location in low memory that cannot be
ioremapped. For example on a P2020-based board with 512MB of RAM the
following error occurs on bootup:
<...>
mpic: requesting IPIs ...
__ioremap(): phys addr 0x1ffff000 is RAM lr c05df9a0
Unable to handle kernel paging request for data at address 0x00000014
Faulting instruction address: 0xc05df9b0
Oops: Kernel access of bad area, sig: 11 [#1]
SMP NR_CPUS=2 P2020 RDB
Modules linked in:
<... eventual kernel panic>
Adding logic to conditionally ioremap or access memory directly resolves
the issue.
Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
Signed-off-by: Nate Case <ncase@xes-inc.com>
Reported-by: Dipen Dudhat <B09055@freescale.com>
Tested-by: Dipen Dudhat <B09055@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
desc->affinity doesn't exit in that case. Let's use a macro for
the UP variant of get_irq_server(), it's the easiest way, avoids
evaluating arguments.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Move the defintion and lock helper routines for the cpu hotplug driver
lock from pseries to powerpc code to avoid build breaks for platforms
other than pseries that use cpu hotplug.
Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com>
Acked-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
get_viotape_info() declares a vio_waitevent on the stack, which
contains a completion, but never initialises the completion.
I have no idea how this ever worked, and on recent kernels it causes
an oops in handle_tape_event() when we access the non-initialised
completion.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Acked-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Make sure compiler won't do weird things with limits. E.g. fetching
them twice may return 2 different values after writable limits are
implemented.
I.e. either use rlimit helpers added in
3e10e716ab
or ACCESS_ONCE if not applicable.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@ozlabs.org
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Commit 57b150cce8 (irq: only update affinity if
->set_affinity() is sucessfull) broke xics irq affinity.
We need to use the cpumask passed in, instead of accessing ->affinity directly.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Fix the following build failures:
arch/powerpc/platforms/embedded6xx/flipper-pic.c: In function 'flipper_pic_map':
arch/powerpc/platforms/embedded6xx/flipper-pic.c:105: error: implicit declaration of function 'get_irq_desc'
arch/powerpc/platforms/embedded6xx/hlwd-pic.c: In function 'hlwd_pic_map':
arch/powerpc/platforms/embedded6xx/hlwd-pic.c:98: error: implicit declaration of function 'get_irq_desc'
These failures are caused by the changes introduced in commit
"powerpc: Remove get_irq_desc()". The reason these drivers were not
updated is that they weren't merged yet.
Signed-off-by: Albert Herranz <albert_herranz@yahoo.es>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Fix the following build failures:
arch/powerpc/platforms/embedded6xx/hlwd-pic.c: In function 'hlwd_pic_irq_cascade':
arch/powerpc/platforms/embedded6xx/hlwd-pic.c:135: error: passing argument 1 of 'spin_lock' from incompatible pointer type
arch/powerpc/platforms/embedded6xx/hlwd-pic.c:137: error: passing argument 1 of 'spin_unlock' from incompatible pointer type
arch/powerpc/platforms/embedded6xx/hlwd-pic.c:145: error: passing argument 1 of 'spin_lock' from incompatible pointer type
arch/powerpc/platforms/embedded6xx/hlwd-pic.c:149: error: passing argument 1 of 'spin_unlock' from incompatible pointer type
These failures are caused by the changes introduced in commit
"genirq: Convert irq_desc.lock to raw_spinlock". The reason this driver
was not updated is that it wasn't merged yet.
Signed-off-by: Albert Herranz <albert_herranz@yahoo.es>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The retry logic in ug_putc() is broken.
If the TX fifo is not ready and the counter runs out it will have a
value of -1 and no transfer should be attempted. Also, a counter
with a value of 0 means that the TX fifo got ready in the last try
and the transfer should be attempted.
Reported-by: "Juha Leppanen" <juha_motorsportcom@luukku.com>
Signed-off-by: "Juha Leppanen" <juha_motorsportcom@luukku.com>
Signed-off-by: Albert Herranz <albert_herranz@yahoo.es>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The _ONSTACK variant should be used for on-stack completion,
otherwise it will break lockdep.
Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@ozlabs.org
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
And add the __acquires() and __releases() annotations, while at it.
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
If an online-attempt on a CPU which has been offlined using H_CEDE
with an appropriate cede latency hint fails, don't panic.
Instead print the error message and let the __cpu_up() code notify the
CPU Hotplug framework of the failure, which in turn can notify the
other subsystem through CPU_UP_CANCELED.
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
It's possible to set CONFIG_XICS without CONFIG_PCI_MSI. When that happens,
the kernel fails to build with
arch/powerpc/platforms/built-in.o: In function `.xics_startup':
xics.c:(.text+0x12f60): undefined reference to `.unmask_msi_irq' make: ***
[.tmp_vmlinux1] Error 1
Furthermore, as noted by Benjamin Herrenschmidt, "CONFIG_XICS should be
made invisible and selected by PSERIES."
This patch fixes PSERIES to select both options
Signed-off-by: Mel Gorman <mel[at]csn.ul.ie>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The wrong variable was returned in the case of an error.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The Collaborative Memory Manager (CMM) module allocates individual pages
over time that are not migratable. On a long running system this can
severely impact the ability to find enough pages to support a hotplug
memory remove operation.
This patch adds a memory isolation notifier and a memory hotplug notifier.
The memory isolation notifier will return the number of pages found in
the range specified. This is used to determine if all of the used pages
in a pageblock are owned by the balloon (or other entities in the notifier
chain). The hotplug notifier will free pages in the range which is to be
removed. The priority of this hotplug notifier is low so that it will be
called near last, this helps avoids removing loaned pages in operations
that fail due to other handlers.
CMM activity will be halted when hotplug remove operations are active and
resume activity after a delay period to allow the hypervisor time to
adjust.
Signed-off-by: Robert Jennings <rcj@linux.vnet.ibm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Brian King <brking@linux.vnet.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Gerald Schaefer <geralds@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* 'for-33' of git://repo.or.cz/linux-kbuild: (29 commits)
net: fix for utsrelease.h moving to generated
gen_init_cpio: fixed fwrite warning
kbuild: fix make clean after mismerge
kbuild: generate modules.builtin
genksyms: properly consider EXPORT_UNUSED_SYMBOL{,_GPL}()
score: add asm/asm-offsets.h wrapper
unifdef: update to upstream revision 1.190
kbuild: specify absolute paths for cscope
kbuild: create include/generated in silentoldconfig
scripts/package: deb-pkg: use fakeroot if available
scripts/package: add KBUILD_PKG_ROOTCMD variable
scripts/package: tar-pkg: use tar --owner=root
Kbuild: clean up marker
net: add net_tstamp.h to headers_install
kbuild: move utsrelease.h to include/generated
kbuild: move autoconf.h to include/generated
drop explicit include of autoconf.h
kbuild: move compile.h to include/generated
kbuild: drop include/asm
kbuild: do not check for include/asm-$ARCH
...
Fixed non-conflicting clean merge of modpost.c as per comments from
Stephen Rothwell (modpost.c had grown an include of linux/autoconf.h
that needed to be changed to generated/autoconf.h)
* 'next' of git://git.secretlab.ca/git/linux-2.6: (23 commits)
powerpc: fix up for mmu_mapin_ram api change
powerpc: wii: allow ioremap within the memory hole
powerpc: allow ioremap within reserved memory regions
wii: use both mem1 and mem2 as ram
wii: bootwrapper: add fixup to calc useable mem2
powerpc: gamecube/wii: early debugging using usbgecko
powerpc: reserve fixmap entries for early debug
powerpc: wii: default config
powerpc: wii: platform support
powerpc: wii: hollywood interrupt controller support
powerpc: broadway processor support
powerpc: wii: bootwrapper bits
powerpc: wii: device tree
powerpc: gamecube: default config
powerpc: gamecube: platform support
powerpc: gamecube/wii: flipper interrupt controller support
powerpc: gamecube/wii: udbg support for usbgecko
powerpc: gamecube/wii: do not include PCI support
powerpc: gamecube/wii: declare as non-coherent platforms
powerpc: gamecube/wii: introduce GAMECUBE_COMMON
...
Fix up conflicts in arch/powerpc/mm/fsl_booke_mmu.c.
Hopefully even close to correctly.
Convert locks which cannot be sleeping locks in preempt-rt to
raw_spinlocks.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Name space cleanup. No functional change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: linux-arch@vger.kernel.org
The raw_spin* namespace was taken by lockdep for the architecture
specific implementations. raw_spin_* would be the ideal name space for
the spinlocks which are not converted to sleeping locks in preempt-rt.
Linus suggested to convert the raw_ to arch_ locks and cleanup the
name space instead of using an artifical name like core_spin,
atomic_spin or whatever
No functional change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: linux-arch@vger.kernel.org
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (34 commits)
m68k: rename global variable vmalloc_end to m68k_vmalloc_end
percpu: add missing per_cpu_ptr_to_phys() definition for UP
percpu: Fix kdump failure if booted with percpu_alloc=page
percpu: make misc percpu symbols unique
percpu: make percpu symbols in ia64 unique
percpu: make percpu symbols in powerpc unique
percpu: make percpu symbols in x86 unique
percpu: make percpu symbols in xen unique
percpu: make percpu symbols in cpufreq unique
percpu: make percpu symbols in oprofile unique
percpu: make percpu symbols in tracer unique
percpu: make percpu symbols under kernel/ and mm/ unique
percpu: remove some sparse warnings
percpu: make alloc_percpu() handle array types
vmalloc: fix use of non-existent percpu variable in put_cpu_var()
this_cpu: Use this_cpu_xx in trace_functions_graph.c
this_cpu: Use this_cpu_xx for ftrace
this_cpu: Use this_cpu_xx in nmi handling
this_cpu: Use this_cpu operations in RCU
this_cpu: Use this_cpu ops for VM statistics
...
Fix up trivial (famous last words) global per-cpu naming conflicts in
arch/x86/kvm/svm.c
mm/slab.c
Enable the flag that allows a platform to ioremap memory marked
as reserved.
This is currently needed on the Nintendo Wii video game console
due to the workaround introduced in "wii: use both mem1 and mem2 as ram".
This will no longer be needed when proper discontig memory support
for 32-bit PowerPC is added to the kernel.
Signed-off-by: Albert Herranz <albert_herranz@yahoo.es>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
The Nintendo Wii video game console has two discontiguous RAM regions:
- MEM1: 24MB @ 0x00000000
- MEM2: 64MB @ 0x10000000
Unfortunately, the kernel currently does not support discontiguous RAM
memory regions on 32-bit PowerPC platforms.
This patch adds a series of workarounds to allow the use of the second
memory region (MEM2) as RAM by the kernel.
Basically, a single range of memory from the beginning of MEM1 to the
end of MEM2 is reported to the kernel, and a memory reservation is
created for the hole between MEM1 and MEM2.
With this patch the system is able to use all the available RAM and not
just ~27% of it.
This will no longer be needed when proper discontig memory support
for 32-bit PowerPC is added to the kernel.
Signed-off-by: Albert Herranz <albert_herranz@yahoo.es>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Add support for using the USB Gecko adapter as an early debugging
console on the Nintendo GameCube and Wii video game consoles.
The USB Gecko is a 3rd party memory card interface adapter that provides
a EXI (External Interface) to USB serial converter.
Signed-off-by: Albert Herranz <albert_herranz@yahoo.es>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Add platform support for the Nintendo Wii video game console.
Signed-off-by: Albert Herranz <albert_herranz@yahoo.es>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Add support for the dual interrupt controller included in the "Hollywood"
chipset of the Nintendo Wii video game console.
This interrupt controller serves both the Broadway processor (as a cascade)
and the Starlet processor, and is used to manage interrupts for the
non-classic hardware.
Signed-off-by: Albert Herranz <albert_herranz@yahoo.es>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Add platform support for the Nintendo GameCube video game console.
Signed-off-by: Albert Herranz <albert_herranz@yahoo.es>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Add support for the interrupt controller included in the "Flipper"
chipset of the Nintendo GameCube video game console.
The same interrupt controller is also present in the "Hollywood" chipset
of the Nintendo Wii.
Signed-off-by: Albert Herranz <albert_herranz@yahoo.es>
Acked-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Add support for using the USB Gecko adapter via the udbg facility on
the Nintendo GameCube and Wii video game consoles.
The USB Gecko is a 3rd party memory card interface adapter that provides
a EXI (External Interface) to USB serial converter.
Signed-off-by: Albert Herranz <albert_herranz@yahoo.es>
Acked-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
The processors bundled in the Nintendo GameCube and Wii video game consoles
require explicit cache handling when DMA engines are used.
Signed-off-by: Albert Herranz <albert_herranz@yahoo.es>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Add a config option GAMECUBE_COMMON to be used as a dependency for all
options common to the Nintendo GameCube and Wii video game consoles.
Signed-off-by: Albert Herranz <albert_herranz@yahoo.es>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (151 commits)
powerpc: Fix usage of 64-bit instruction in 32-bit altivec code
MAINTAINERS: Add PowerPC patterns
powerpc/pseries: Track previous CPPR values to correctly EOI interrupts
powerpc/pseries: Correct pseries/dlpar.c build break without CONFIG_SMP
powerpc: Make "intspec" pointers in irq_host->xlate() const
powerpc/8xx: DTLB Miss cleanup
powerpc/8xx: Remove DIRTY pte handling in DTLB Error.
powerpc/8xx: Start using dcbX instructions in various copy routines
powerpc/8xx: Restore _PAGE_WRITETHRU
powerpc/8xx: Add missing Guarded setting in DTLB Error.
powerpc/8xx: Fixup DAR from buggy dcbX instructions.
powerpc/8xx: Tag DAR with 0x00f0 to catch buggy instructions.
powerpc/8xx: Update TLB asm so it behaves as linux mm expects.
powerpc/8xx: Invalidate non present TLBs
powerpc/pseries: Serialize cpu hotplug operations during deactivate Vs deallocate
pseries/pseries: Add code to online/offline CPUs of a DLPAR node
powerpc: stop_this_cpu: remove the cpu from the online map.
powerpc/pseries: Add kernel based CPU DLPAR handling
sysfs/cpu: Add probe/release files
powerpc/pseries: Kernel DLPAR Infrastructure
...
There is no longer any use of the include2/ directory.
The generated files has moved to include/generated.
Drop all references to said directory.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>
We need to save SICRL, SICRH and SCCR registers on suspend, and restore
them on resume. Otherwise, we lose IO and clocks setup on MPC8315E-RDB
boards when ULPI USB PHY is used (non-POR setup).
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Currently 83xx PMC driver clears deep_sleeping variable very early,
before devices are resumed. This makes fsl_deep_sleep() unusable in
drivers' resume() callback.
Sure, drivers can store fsl_deep_sleep() value on suspend and use
the stored value on resume. But a better solution is to postpone
clearing the deep_sleeping variable, i.e. move it into finish()
callback.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
At the moment when we EOI an interrupt we set the CPPR back to 0xFF
regardless of its previous value. This could lead to problems if we
take an interrupt with a priority of 5, but before EOIing it we get
an IPI which has a priority of 4. The problem is that at the moment
when we EOI the IPI we will set the CPPR to 0xFF, but it should
really be set back to 5 (the previous priority).
To keep track of the previous CPPR values we create the xics_cppr
structure that has an array for CPPR values and an index pointing
to the current priority. This can easily grow if new priorities get
added in the future.
This will also be useful because the partition adjunct option of
upcoming machines will update the H_XIRR hcall to accept the CPPR
as a parameter.
Signed-off-by: Mark Nelson <markn@au1.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The recent patch to add cpu offline/online as part of the DLPAR
process for pseries causes a build break if CONFIG_SMP is not
defined. Original patch here;
http://lists.ozlabs.org/pipermail/linuxppc-dev/2009-November/078299.html
This corrects the build break by moving the online_node_cpus
and offline_node_cpus under the #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
portions of dlpar.c.
This patch also slightly modifies the online_node_cpus and offline_node_cpus
routines to prepend dlpar_ to the them and make them static. These two
routine are only used in the dlpar add/remove of cpus and these changes
should help clarify that.
Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Writing a driver using SCLPC on the MPC5200B I detected, that the
intspec arrays to map irqs to Linux virq cannot be const, because the
mapping and xlate functions only take non const pointers. All those
functions do not modify the intspec, so a const pointer could be used.
Signed-off-by: Roman Fietze <roman.fietze@telemotive.de>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Currently the cpu-allocation/deallocation process comprises of two steps:
- Set the indicators and to update the device tree with DLPAR node
information.
- Online/offline the allocated/deallocated CPU.
This is achieved by writing to the sysfs tunables "probe" during allocation
and "release" during deallocation.
At the sametime, the userspace can independently online/offline the CPUs of
the system using the sysfs tunable "online".
It is quite possible that when a userspace tool offlines a CPU
for the purpose of deallocation and is in the process of updating the device
tree, some other userspace tool could bring the CPU back online by writing to
the "online" sysfs tunable thereby causing the deallocate process to fail.
The solution to this is to serialize writes to the "probe/release" sysfs
tunable with the writes to the "online" sysfs tunable.
This patch employs a mutex to provide this serialization, which is a no-op on
all architectures except PPC_PSERIES
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Acked-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
