Make some changes to the NEED_RESCHED and POLLING_NRFLAG to reduce
confusion, and make their semantics rigid. Improves efficiency of
resched_task and some cpu_idle routines.
* In resched_task:
- TIF_NEED_RESCHED is only cleared with the task's runqueue lock held,
and as we hold it during resched_task, then there is no need for an
atomic test and set there. The only other time this should be set is
when the task's quantum expires, in the timer interrupt - this is
protected against because the rq lock is irq-safe.
- If TIF_NEED_RESCHED is set, then we don't need to do anything. It
won't get unset until the task get's schedule()d off.
- If we are running on the same CPU as the task we resched, then set
TIF_NEED_RESCHED and no further action is required.
- If we are running on another CPU, and TIF_POLLING_NRFLAG is *not* set
after TIF_NEED_RESCHED has been set, then we need to send an IPI.
Using these rules, we are able to remove the test and set operation in
resched_task, and make clear the previously vague semantics of
POLLING_NRFLAG.
* In idle routines:
- Enter cpu_idle with preempt disabled. When the need_resched() condition
becomes true, explicitly call schedule(). This makes things a bit clearer
(IMO), but haven't updated all architectures yet.
- Many do a test and clear of TIF_NEED_RESCHED for some reason. According
to the resched_task rules, this isn't needed (and actually breaks the
assumption that TIF_NEED_RESCHED is only cleared with the runqueue lock
held). So remove that. Generally one less locked memory op when switching
to the idle thread.
- Many idle routines clear TIF_POLLING_NRFLAG, and only set it in the inner
most polling idle loops. The above resched_task semantics allow it to be
set until before the last time need_resched() is checked before going into
a halt requiring interrupt wakeup.
Many idle routines simply never enter such a halt, and so POLLING_NRFLAG
can be always left set, completely eliminating resched IPIs when rescheduling
the idle task.
POLLING_NRFLAG width can be increased, to reduce the chance of resched IPIs.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Con Kolivas <kernel@kolivas.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Run idle threads with preempt disabled.
Also corrected a bugs in arm26's cpu_idle (make it actually call schedule()).
How did it ever work before?
Might fix the CPU hotplugging hang which Nigel Cunningham noted.
We think the bug hits if the idle thread is preempted after checking
need_resched() and before going to sleep, then the CPU offlined.
After calling stop_machine_run, the CPU eventually returns from preemption and
into the idle thread and goes to sleep. The CPU will continue executing
previous idle and have no chance to call play_dead.
By disabling preemption until we are ready to explicitly schedule, this bug is
fixed and the idle threads generally become more robust.
From: alexs <ashepard@u.washington.edu>
PPC build fix
From: Yoichi Yuasa <yuasa@hh.iij4u.or.jp>
MIPS build fix
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Yoichi Yuasa <yuasa@hh.iij4u.or.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
CPU freq support using 970FX powertune facility for iMac G5 and SMU
based single CPU desktop.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This is the arch/ part of the big kfree cleanup patch.
Remove pointless checks for NULL prior to calling kfree() in arch/.
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Acked-by: Grant Grundler <grundler@parisc-linux.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Define ppc_md.set_dabr for both 32 + 64 bit. Cleanup the implementation for
pSeries also, it was needlessly complex. Now we just do two firmware tests at
setup time, and use one of two functions, rather than using one function and
testing on every call.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Mostly this involves adding #include <asm/smp.h>, since that defines
things like boot_cpuid[_phys] and [gs]et_hard_smp_processor_id, which
are SMP-related but still needed on UP. This incorporates fixes
posted by Olof Johansson and Heikki Lindholm.
Signed-off-by: Paul Mackerras <paulus@samba.org>
The ancient ppcdebug/PPCDBG mechanism is now only used in two places.
First, in the hash setup code, one of the bits allows the size of the
hash table to be reduced by a factor of 8 - which would be better
accomplished with a command line option for that purpose. The other
was a bunch of bus walking related messages in the iSeries code, which
would seem to be insufficient reason to keep the mechanism.
This patch removes the last traces of this mechanism.
Built and booted on iSeries and pSeries POWER5 LPAR (ARCH=powerpc).
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Adds a new CONFIG_PPC_64K_PAGES which, when enabled, changes the kernel
base page size to 64K. The resulting kernel still boots on any
hardware. On current machines with 4K pages support only, the kernel
will maintain 16 "subpages" for each 64K page transparently.
Note that while real 64K capable HW has been tested, the current patch
will not enable it yet as such hardware is not released yet, and I'm
still verifying with the firmware architects the proper to get the
information from the newer hypervisors.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This also moves setup_cpu_maps to setup-common.c (calling it
smp_setup_cpu_maps) and uses it on both 32-bit and 64-bit.
Signed-off-by: Paul Mackerras <paulus@samba.org>
register_vpa() doesn't actually do a VPA register call it just uses the flags
you pass it, so rename it to vpa_call() to be clearer.
We can then define register_vpa() and unregister_vpa() which are both simple
wrappers around vpa_call(). (we'll need unregister_vpa() for kexec soon)
We can then cleanup vpa_init(), and because vpa_init() is only called from
platforms/pseries we remove the definition in asm-ppc64/smp.h.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Currently there is no Kconfig symbol to indicate that we want nvram
support on 64-bit kernels; it's assumed we always want it, so make
the powermac setup code always initialize the pmac nvram code if
64-bit.
Signed-off-by: Paul Mackerras <paulus@samba.org>
The extraction of PCI stuff from struct device_node left some false
assumptions in notifier code. As a result, dynamic add crashes when
non-PCI nodes are added. This patch fixes these assumptions.
Signed-off-by: John Rose <johnrose@austin.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Move plpar_wrappers.h into arch/powerpc/platforms/pseries, fixup white space,
and update callers.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Move pSeries specific code in set_dabr() into a ppc_md function, this will
allow us to keep plpar_wrappers.h private to platforms/pseries.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
This moves rtas-proc.c and rtas_flash.c into arch/powerpc/kernel, since
cell wants them as well as pseries (and chrp can use rtas-proc.c too,
at least in principle). rtas_fw.c is gone, with its bits moved into
rtas_flash.c and rtas.c.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Include asm/rtas.h for prototype for rtas_call etc., and make the
`done' variable unsigned int since that's what rtas_call wants.
Signed-off-by: Paul Mackerras <paulus@samba.org>
These days, the NACA only exists on iSeries. Therefore, this patch
moves naca.h from include/asm-ppc64 to arch/powerpc/platforms/iseries.
There was one file including naca.h outside of platforms/iseries -
arch/ppc64/kernel/udbg_scc.c. However, that's obviously a hangover
from older days. The include is not necessary, so this patch simply
removes it.
Built and booted on iSeries, built for G5 (which uses udbg_scc.o).
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
We were getting powerbook sleep code included, and giving compile
errors, with CONFIG_PM=y on a 64-bit build. This excludes that code
so the kernel will compile. One day BenH will implement on sleep on
the G5...
Signed-off-by: Paul Mackerras <paulus@samba.org>
The nvram driver imported from the ppc code uses call_rtas, but
rtas_call is the name we are using in merged code (since ppc64 used
that name, and it uses far more RTAS calls than ppc32).
Signed-off-by: Paul Mackerras <paulus@samba.org>
A recent commit that removed rtas-fw.h and moved its contents to
include/asm-powerpc/rtas.h forgot to also remove the inclusion of
it in arch/powerpc/platforms/pseries/setup.c.
Signed-off-by: Paul Mackerras <paulus@samba.org>
This patch simply moves files over to arch/powerpc without making
any changes to them.
Signed-off-by: Arnd Bergmann <arndb@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Cell uses the same code as pSeries for flashing the firmware
through rtas, so the implementation should not be part of
platforms/pseries.
Put it into arch/powerpc/kernel instead.
Signed-off-by: Arnd Bergmann <arndb@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
During the conversion to the merge tree, the Cell specific
SMP initialization was removed from the pSeries code.
This creates a new Cell specific SMP implementation file.
Signed-off-by: Arnd Bergmann <arndb@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
By parsing the command line earlier, we can add the mem= value to the
flattened device tree and let the generic code sort out the memory limit
for us.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
We had a static memory_limit in prom.c, and then another one defined
in setup_64.c and used in numa.c, which resulted in the kernel crashing
when mem=xxx was given on the command line. This puts the declaration
in system.h and the definition in mem.c. This also moves the
definition of tce_alloc_start/end out of setup_64.c.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Add proper entry to support the Marvell MV64361 (Marvell Discovery II)
SRAM.
This feature may be used by the mv643xx_eth driver.
Signed-off-by: Nicolas DET <det.nicolas@free.fr>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This implements a nvram acccess method, similar to
arch/ppc64/kernel/pSeries_nvram.c tested on CHRP B50.
Signed-off-by: Olaf Hering <olh@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
