Impact: Reduce future system panics due to cpumask operations using NR_CPUS

Insure that code does not look at bits >= nr_cpu_ids as when cpumasks are
allocated based on nr_cpu_ids, these extra bits will not be defined.

Also some other minor updates:

   * change in to use cpu accessor function set_cpu_present() instead of
     directly accessing cpu_present_map w/cpu_clear() [arch/x86/kernel/reboot.c]

   * use cpumask_of() instead of &cpumask_of_cpu() [arch/x86/kernel/reboot.c]

   * optimize some cpu_mask_to_apicid_and functions.
Signed-off-by: NMike Travis <travis@sgi.com>
Acked-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: enables /sys/devices/system/cpu/{kernel_max,offline} user interface

By setting total_cpus, the drivers/base/cpu.c will display the
values of kernel_max (NR_CPUS-1) and the offlined cpu map.
Signed-off-by: NMike Travis <travis@sgi.com>
Acked-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: New API

Like cpu_coregroup_map, but returns a (const) pointer.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NMike Travis <travis@sgi.com>
Cc: Ingo Molnar <mingo@redhat.com>

Impact: fix a crash/hard-reboot on certain configs while enabling cpu runtime

On some archs, the boot of a secondary cpu can have an early fragile state.
On x86-64, the pda is not initialized on the first stage of a cpu boot but
it is needed to get the cpu number and the current task pointer. This data
is needed during tracing. As they were dereferenced at this stage, we got a
crash while tracing a cpu being enabled at runtime.

Some other archs like ia64 can have such kind of issue too.

Changes on v2:

We dropped the previous solution of a per-arch called function to guess the
current state of a cpu. That could slow down the tracing.

This patch removes the -pg flag on arch/x86/kernel/cpu/common.c where
the low level cpu boot functions exist, on start_secondary() and a helper
function used at this stage.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Acked-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: add new boot parameter

Use possible_cpus=NUM kernel parameter to extend the number of possible
cpus.

The ability to HOTPLUG ON cpus that are "possible" but not "present" is
dealt with in a later patch.
Signed-off-by: NMike Travis <travis@sgi.com>

Impact: cleanup, remove on-stack cpumask.

The "map" arg is always cpu_online_mask.  Importantly, set_affinity
always ands the argument with cpu_online_mask anyway, so we don't need
to do it in fixup_irqs(), avoiding a temporary.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NMike Travis <travis@sgi.com>

VMI initialiation can relocate the fixmap, causing early_ioremap to
malfunction if it is initialized before the relocation.  To fix this,
VMI activation is split into two phases; the detection, which must
happen before setting up ioremap, and the activation, which must happen
after parsing early boot parameters.

This fixes a crash on boot when VMI is enabled under VMware.
Signed-off-by: NZachary Amsden <zach@vmware.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Impact: cleanup

Each SMP arch defines these themselves.  Move them to a central
location.

Twists:
1) Some archs (m32, parisc, s390) set possible_map to all 1, so we add a
   CONFIG_INIT_ALL_POSSIBLE for this rather than break them.

2) mips and sparc32 '#define cpu_possible_map phys_cpu_present_map'.
   Those archs simply have phys_cpu_present_map replaced everywhere.

3) Alpha defined cpu_possible_map to cpu_present_map; this is tricky
   so I just manipulate them both in sync.

4) IA64, cris and m32r have gratuitous 'extern cpumask_t cpu_possible_map'
   declarations.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Reviewed-by: NGrant Grundler <grundler@parisc-linux.org>
Tested-by: NTony Luck <tony.luck@intel.com>
Acked-by: NIngo Molnar <mingo@elte.hu>
Cc: Mike Travis <travis@sgi.com>
Cc: ink@jurassic.park.msu.ru
Cc: rmk@arm.linux.org.uk
Cc: starvik@axis.com
Cc: tony.luck@intel.com
Cc: takata@linux-m32r.org
Cc: ralf@linux-mips.org
Cc: grundler@parisc-linux.org
Cc: paulus@samba.org
Cc: schwidefsky@de.ibm.com
Cc: lethal@linux-sh.org
Cc: wli@holomorphy.com
Cc: davem@davemloft.net
Cc: jdike@addtoit.com
Cc: mingo@redhat.com

Just come across this when booting on an old hw..
Looks somewhat ugly, that single missing space ;)
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: fix wakeup_secondary_cpu with hotplug

We can not put that into x86_quirks, because that is __initdata.
So try to move that to genapic, and add update_genapic in x86_quirks.

later we even could use that stub to:

 1. autodetect CONFIG_ES7000_CLUSTERED_APIC
 2. more correct inquire_remote_apic with apic_verbosity setting.
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: fix secondary-CPU wakeup/init path with numaq and es7000

While looking at wakeup_secondary_cpu for WAKE_SECONDARY_VIA_NMI:

|#ifdef WAKE_SECONDARY_VIA_NMI
|/*
| * Poke the other CPU in the eye via NMI to wake it up. Remember that the normal
| * INIT, INIT, STARTUP sequence will reset the chip hard for us, and this
| * won't ... remember to clear down the APIC, etc later.
| */
|static int __devinit
|wakeup_secondary_cpu(int logical_apicid, unsigned long start_eip)
|{
|        unsigned long send_status, accept_status = 0;
|        int maxlvt;
|...
|        if (APIC_INTEGRATED(apic_version[phys_apicid])) {
|                maxlvt = lapic_get_maxlvt();

I noticed that there is no warning about undefined phys_apicid...

because WAKE_SECONDARY_VIA_NMI and WAKE_SECONDARY_VIA_INIT can not be
defined at the same time. So NUMAQ is using wrong wakeup_secondary_cpu.

WAKE_SECONDARY_VIA_NMI, WAKE_SECONDARY_VIA_INIT and
WAKE_SECONDARY_VIA_MIP are variants of a weird and fragile
preprocessor-driven "HAL" mechanisms to specify the kind of secondary-CPU
wakeup strategy a given x86 kernel will use.

The vast majority of systems want to use INIT for secondary wakeup - NUMAQ
uses an NMI, (old-style-) ES7000 uses 'MIP' (a firmware driven in-memory
flag to let secondaries continue).

So convert these mechanisms to x86_quirks and add a
->wakeup_secondary_cpu() method to specify the rare exception
to the sane default.

Extend genapic accordingly as well, for 32-bit.

While looking further, I noticed that functions in wakecup.h for numaq
and es7000 are different to the default in mach_wakecpu.h - but smpboot.c
will only use default mach_wakecpu.h with smphook.h.

So we need to add mach_wakecpu.h for mach_generic, to properly support
numaq and es7000, and vectorize the following SMP init methods:

	int trampoline_phys_low;
	int trampoline_phys_high;
	void (*wait_for_init_deassert)(atomic_t *deassert);
	void (*smp_callin_clear_local_apic)(void);
	void (*store_NMI_vector)(unsigned short *high, unsigned short *low);
	void (*restore_NMI_vector)(unsigned short *high, unsigned short *low);
	void (*inquire_remote_apic)(int apicid);
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: fix APIC IRQ irregularities on certain older boxes

We should touch the APIC ESR register if only we have it.

The patch fixes the problem mentioned by Max Kellermann:

	http://lkml.org/lkml/2008/10/17/147Bisected-by: NMax Kellermann <mk@cm4all.com>
Signed-off-by: NCyrill Gorcunov <gorcunov@gmail.com>
[ mingo@elte.hu: build fix ]
Signed-off-by: NIngo Molnar <mingo@elte.hu>

It's somewhat unlikely that it happens, but right now a race window
between interrupts or machine checks or oopses could corrupt the tainted
bitmap because it is modified in a non atomic fashion.

Convert the taint variable to an unsigned long and use only atomic bit
operations on it.

Unfortunately this means the intvec sysctl functions cannot be used on it
anymore.

It turned out the taint sysctl handler could actually be simplified a bit
(since it only increases capabilities) so this patch actually removes
code.

[akpm@linux-foundation.org: remove unneeded include]
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

remove remainder of additional_cpus logic. We now just listen to the
disabled_cpus value like we did for years. disabled_cpus is always >=
0 so no need for an extra check.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

additional_cpus=<x> parameter is dangerous and broken: for example
if we boot additional_cpus=-2 on a stock dual-core system it will
crash the box on bootup.

So reduce the maze of code a bit by removingthe user-configurability
angle.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

x86: allow number of additional hotplug CPUs to be set at compile time, V2

The default number of additional CPU IDs for hotplugging is determined
by asking ACPI or mptables how many "disabled" CPUs there are in the
system, but many systems get this wrong so that e.g. a uniprocessor
machine gets an extra CPU allocated and never switches to single CPU
mode.

And sometimes CPU hotplugging is enabled only for suspend/hibernate
anyway, so the additional CPU IDs are not wanted. Allow the number
to be set to zero at compile time.

Also, force the number of extra CPUs to zero if hotplugging is disabled
which allows removing some conditional code.

Tested on uniprocessor x86_64 that ACPI claims has a disabled processor,
with CPU hotplugging configured.

("After" has the number of additional CPUs set to 0)
Before: NR_CPUS: 512, nr_cpu_ids: 2, nr_node_ids 1
After: NR_CPUS: 512, nr_cpu_ids: 1, nr_node_ids 1

[Changed the name of the option and the prompt according to Ingo's
 suggestion.]
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Commit 4a701737 ("x86: move prefill_possible_map calling early, fix")
is the wrong fix: prefill_possible_map() needs to be available
even when CONFIG_HOTPLUG_CPU is not set. A followon patch will do that.

Fix this correctly by making prefill_possible_map() available even when
CONFIG_HOTPLUG_CPU is not set. The function is needed so that
the number of possible CPUs can be determined.

Tested on uniprocessor machine with CPU hotplug disabled.

From boot log:
  Before: NR_CPUS: 512, nr_cpu_ids: 512, nr_node_ids 1
  After: NR_CPUS: 512, nr_cpu_ids: 1, nr_node_ids 1
Signed-off-by: NChuck Ebbert <cebbert@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

We should check if we have ESR register before reading from it.
Signed-off-by: NCyrill Gorcunov <gorcunov@gmail.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Secondary cpus start with local interrupts disabled.
start_secondary() first initializes the new cpu, then it enables the
local interrupts. (although interrupts are enabled within smp_callin()
as well).

Right now, the local interrupts are enabled as a side effect of calling
ipi_call_lock_irq().

The attached patch clarifies when local interrupts are enabled.
Signed-off-by: NManfred Spraul <manfred@colorfullife.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Right now, there is no notifier that is called on a new cpu, before the new
cpu begins processing interrupts/softirqs.
Various kernel function would need that notification, e.g. kvm works around
by calling smp_call_function_single(), rcu polls cpu_online_map.

The patch adds a CPU_STARTING notification. It also adds a helper function
that sends the message to all cpu_chain handlers.

Tested on x86-64.
All other archs are untested. Especially on sparc, I'm not sure if I got
it right.
Signed-off-by: NManfred Spraul <manfred@colorfullife.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

It allows paravirt implementations of cpu_disable to share the
cpu_disable_common code, without having to take on board APIC
writes, which may not be appropriate.
Signed-off-by: NAlex Nixon <alex.nixon@citrix.com>
Acked-by: NJeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Add the new play_dead into smpboot.c, as it fits more cleanly in there
alongside other CONFIG_HOTPLUG functions.

Separate out the common code into its own function.
Signed-off-by: NAlex Nixon <alex.nixon@citrix.com>
Acked-by: NJeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NAlex Nixon <alex.nixon@citrix.com>
Acked-by: NJeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

WARNING: vmlinux.o(.cpuinit.text+0x3cc4): Section mismatch in reference from the function uv_cpu_init() to the function .init.text:uv_system_init()
The function __cpuinit uv_cpu_init() references
a function __init uv_system_init().
If uv_system_init is only used by uv_cpu_init then
annotate uv_system_init with a matching annotation.

uv_system_init was ment to be called only once, so do it from codepath
(native_smp_prepare_cpus) which is called once, right before activation
of other cpus (smp_init).

Note: old code relied on uv_node_to_blade being initialized to 0,
but it'a not initialized from anywhere.
Signed-off-by: NMarcin Slusarz <marcin.slusarz@gmail.com>
Acked-by: NJack Steiner <steiner@sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Take out part of get_local_pda referencing __init function (free_bootmem)
to new (static) function marked as __ref. It's safe to do because free_bootmem
is called before __init sections are dropped.

WARNING: vmlinux.o(.cpuinit.text+0x3cd7): Section mismatch in reference from the function get_local_pda() to the function .init.text:free_bootmem()
The function __cpuinit get_local_pda() references
a function __init free_bootmem().
If free_bootmem is only used by get_local_pda then
annotate free_bootmem with a matching annotation.
Signed-off-by: NMarcin Slusarz <marcin.slusarz@gmail.com>
Cc: Mike Travis <travis@sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

prefill_possible_map() is defined inside CONFIG_HOTPLUG_CPU,
so the nesting CONFIG_HOTPLUG_CPU is just redundant.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

clear bits for cpu nr > 8.

This allows us to boot the full range of possible CPUs that the
supported APIC model will allow. Previously we'd hang or boot up
with less than 8 CPUs.
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Tested-by: NJeff Chua <jeff.chua.linux@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

For some reason we had two parsers registered for maxcpus=. One in init/main.c
and another in arch/x86/smpboot.c. So I nuked the one in arch/x86.

Also 64-bit kernels used to handle maxcpus= as documented in
Documentation/cpu-hotplug.txt. CPUs with 'id > maxcpus' are initialized
but not booted. 32-bit version for some reason ignored them even though
all the infrastructure for booting them later is there.

In the current mainline both 64 and 32 bit versions are broken.
This patch restores the correct behaviour. I've tested x86_64 version on
4- and 8- way Core2 and 2-way Opteron based machines. Various config
combinations SMP, !SMP, CPU_HOTPLUG, !CPU_HOTPLUG.
Booted with maxcpus=1 and maxcpus=4, etc. Everything is working as expected.

So far we've received two reports from different people confirming that 32-bit
version also works fine, both on dual core laptops and 16way server machines.

[v2: This version fixes visws breakage pointed out by Ingo.]
Signed-off-by: NMax Krasnyansky <maxk@qualcomm.com>
Cc: lizf@cn.fujitsu.com
Cc: jeff.chua.linux@gmail.com
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Jeff Chua reported that booting a !bigsmp kernel on a 16-way box
hangs silently.

this is a long-standing issue, smp start AP cpu could check the
apic id >=8 etc before trying to start it.

achieve this by moving the def_to_bigsmp check later and skip the
apicid id > 8

[ mingo@elte.hu: clean up the message that is printed. ]
Reported-by: N"Jeff Chua" <jeff.chua.linux@gmail.com>
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

 arch/x86/kernel/setup.c   |    6 ------
 arch/x86/kernel/smpboot.c |   10 ++++++++++
 2 files changed, 10 insertions(+), 6 deletions(-)

Having cpu_online_map change during assign_irq_vector can result
in some really nasty and weird things happening.  The one that
bit me last time was accessing non existent per cpu memory for non
existent cpus.

This locking was removed in a sloppy x86_64 and x86_32 merge patch.

Guys can we please try and avoid subtly breaking x86 when we are
merging files together?
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Signed-off-by: NJaswinder Singh <jaswinder@infradead.org>

There are a couple of places where (P)Dprintk is used which is an old
compile time enabled printk wrapper. Convert it to the generic
pr_debug().
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Use alternatives to select the workaround for the 11AP Pentium erratum
for the affected steppings on the fly rather than build time.  Remove the
X86_GOOD_APIC configuration option and replace all the calls to
apic_write_around() with plain apic_write(), protecting accesses to the
ESR as appropriate due to the 3AP Pentium erratum.  Remove
apic_read_around() and all its invocations altogether as not needed.
Remove apic_write_atomic() and all its implementing backends.  The use of
ASM_OUTPUT2() is not strictly needed for input constraints, but I have
used it for readability's sake.

I had the feeling no one else was brave enough to do it, so I went ahead
and here it is.  Verified by checking the generated assembly and tested
with both a 32-bit and a 64-bit configuration, also with the 11AP
"feature" forced on and verified with gdb on /proc/kcore to work as
expected (as an 11AP machines are quite hard to get hands on these days).
Some script complained about the use of "volatile", but apic_write() needs
it for the same reason and is effectively a replacement for writel(), so I
have disregarded it.

I am not sure what the policy wrt defconfig files is, they are generated
and there is risk of a conflict resulting from an unrelated change, so I
have left changes to them out.  The option will get removed from them at
the next run.

Some testing with machines other than mine will be needed to avoid some
stupid mistake, but despite its volume, the change is not really that
intrusive, so I am fairly confident that because it works for me, it will
everywhere.
Signed-off-by: NMaciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This allows Xen's xen_cpu_up() to allocate a pda for the new CPU.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

also remove GET_APIC_ID when read_apic_id is used.

need to apply after
	[PATCH] x86: mach_apicdef.h need to include before smp.h
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

x2apic support.  Interrupt-remapping must be enabled before enabling x2apic,
this is needed to ensure that IO interrupts continue to work properly after the
cpu mode is changed to x2apic(which uses 32bit extended physical/cluster
apic id).

On systems where apicid's are > 255, BIOS can handover the control to OS in
x2apic mode. Or if the OS handover was in legacy xapic mode, check
if it is capable of x2apic mode. And if we succeed in enabling
Interrupt-remapping, then we can enable x2apic mode in the CPU.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: akpm@linux-foundation.org
Cc: arjan@linux.intel.com
Cc: andi@firstfloor.org
Cc: ebiederm@xmission.com
Cc: jbarnes@virtuousgeek.org
Cc: steiner@sgi.com
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Introduce basic apic operations which handle the apic programming. This
will be used later to introduce another specific operations for x2apic.

For the perfomance critial accesses like IPI's, EOI etc, we use the
native operations as they are already referenced by different
indirections like genapic, irq_chip etc.

64bit Paravirt ops can also define their apic operations accordingly.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: akpm@linux-foundation.org
Cc: arjan@linux.intel.com
Cc: andi@firstfloor.org
Cc: ebiederm@xmission.com
Cc: jbarnes@virtuousgeek.org
Cc: steiner@sgi.com
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NCyrill Gorcunov <gorcunov@gmail.com>
Cc: akpm@linux-foundation.org
Cc: andi@firstfloor.org
Signed-off-by: NIngo Molnar <mingo@elte.hu>