On Intel platforms, we can use logical flat mode if there are <= 8
logical cpu's (irrespective of physical apic id values). This will
enable simplified and efficient IPI and device interrupt routing on
such platforms.

Fix the relevant comments while we are at it.

We can clean up default_setup_apic_routing() by using apic->probe()
but that is a different item.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: "yinghai@kernel.org" <yinghai@kernel.org>
LKML-Reference: <1253327399.3948.747.camel@sbs-t61.sc.intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

2.6.31-rc7 does not boot on vSMP systems:

[    8.501108] CPU31: Thermal monitoring enabled (TM1)
[    8.501127] CPU 31 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[    8.650254] CPU31: Intel(R) Xeon(R) CPU           E5540  @ 2.53GHz stepping 04
[    8.710324] Brought up 32 CPUs
[    8.713916] Total of 32 processors activated (162314.96 BogoMIPS).
[    8.721489] ERROR: parent span is not a superset of domain->span
[    8.727686] ERROR: domain->groups does not contain CPU0
[    8.733091] ERROR: groups don't span domain->span
[    8.737975] ERROR: domain->cpu_power not set
[    8.742416]

Ravikiran Thirumalai bisected it to:

| commit 2759c328
| x86: don't call read_apic_id if !cpu_has_apic

The problem is that on vSMP systems the CPUID derived
initial-APICIDs are overlapping - so we need to fall
back on hard_smp_processor_id() which reads the local
APIC.

Both come from the hardware (influenced by firmware
though) so it's a tough call which one to trust.

Doing the quirk expresses the vSMP property properly
and also does not affect other systems, so we go for
this solution instead of a revert.
Reported-and-Tested-by: NRavikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Shai Fultheim <shai@scalex86.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <4A944D3C.5030100@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

KVM would like to provide x2APIC interface to a guest without emulating
interrupt remapping device. The reason KVM prefers guest to use x2APIC
is that x2APIC interface is better virtualizable and provides better
performance than mmio xAPIC interface:

 - msr exits are faster than mmio (no page table walk, emulation)
 - no need to read back ICR to look at the busy bit
 - one 64 bit ICR write instead of two 32 bit writes
 - shared code with the Hyper-V paravirt interface

Included patch changes x2APIC enabling logic to enable it even if IR
initialization failed, but kernel runs under KVM and no apic id is
greater than 255 (if there is one spec requires BIOS to move to x2apic
mode before starting an OS).

-v2: fix build
-v3: fix bug causing compiler warning
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Acked-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: Sheng Yang <sheng@linux.intel.com>
Cc: "avi@redhat.com" <avi@redhat.com>
LKML-Reference: <20090720122417.GR5638@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Add x2apic_supported() to clean up CONFIG_X86_X2APIC checks.

Fix CONFIG_INTR_REMAP checks.

[ Impact: cleanup ]
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: dwmw2@infradead.org
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Weidong Han <weidong.han@intel.com>
LKML-Reference: <20090420200450.128993000@linux-os.sc.intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup

Clean up #ifdefs and replace them with helper functions.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Impact: interface augmentation (not yet used)

Enable fault handling flow for intr-remapping aswell. Fault handling
code now shared by both dma-remapping and intr-remapping.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Impact: cleanup

x86_quirks->update_apic() calling looks crazy. so try to remove it:

 1. every apic take wakeup_cpu member directly
 2. separate es7000_apic to es7000_apic_cluster
 3. use uv_wakeup_cpu directly
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

If BIOS hands over the control to OS in legacy xapic mode, select
legacy xapic related ops in the early apic probe and shift to x2apic
ops later in the boot sequence, only after enabling x2apic mode.

If BIOS hands over the control in x2apic mode, select x2apic related
ops in the early apic probe.

This fixes the early boot panic, where we were selecting x2apic ops,
while the cpu is still in legacy xapic mode.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Move the 32-bit extended-arch APIC drivers to arch/x86/kernel/apic/
too, and rename apic_64.c to probe_64.c.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/kernel/ is getting a bit crowded, and the APIC
drivers are scattered into various different files.

Move them to arch/x86/kernel/apic/*, and also remove
the 'gen' prefix from those which had it.

Also move APIC related functionality: the IO-APIC driver,
the NMI and the IPI code.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup

Now that all APIC code is consolidated there's nothing 'gen' about
apics anymore - so rename 'struct genapic' to 'struct apic'.

This shortens the code and is nicer to read as well.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup

Remove genapic.h and remove all references to it.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

- make oprofile build
- select X86_X2APIC from X86_UV - it relies on it
- export genapic for oprofile modular build
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup

make it simpler, don't need have one extra struct.

v2: fix the sgi_uv build
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup

so could deselect x2apic
and INTR_REMAP will select x2apic
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Our send_IPI_*() methods and definitions are a twisted mess: the same
symbol is defined to different things depending on .config details,
in a non-transparent way.

 - spread out the quirks into separately named per apic driver methods

 - prefix the standard PC methods with default_

 - get rid of wrapper macro obfuscation

 - clean up various details
Signed-off-by: NIngo Molnar <mingo@elte.hu>

- separate the namespace

 - remove macros

 - remove namespace clash on 64-bit
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: refactor code

x86 subarchitectures each defined a "acpi_madt_oem_check()" method,
which could be an inline function, or an extern, or a static function,
and which was also the name of a genapic field.

Untangle this namespace spaghetti by setting ->acpi_madt_oem_check()
to NULL on those subarchitectures that have no detection quirks,
and rename the other ones (summit, es7000) that do.

Also change default_acpi_madt_oem_check() to handle NULL entries,
and clean its control flow up as well.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Rename genapic-> to apic-> references because in a future chagne we'll
open-code all the indirect calls (instead of obscuring them via macros),
so we want this reference to be as short as possible.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Make X86 SGI Ultraviolet support configurable. Saves about 13K of text size
on my modest config.

   text    data     bss     dec     hex filename
6770537 1158680  694356 8623573  8395d5 vmlinux
6757492 1157664  694228 8609384  835e68 vmlinux.nouv
Signed-off-by: NNick Piggin <npiggin@suse.de>
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>

Exports needed by the GRU driver.
Signed-off-by: NJack Steiner <steiner@sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

intr_remapping_enabled get assigned later, so need to check that
in setup_apic_routing
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

introducing an APIC handling probing abstraction:

 static struct genapic *apic_probe[] __initdata = {
	&apic_x2apic_uv_x,
	&apic_x2apic_phys,
	&apic_x2apic_cluster,
	&apic_physflat,
	NULL,
 };

This way we can remove UV, x2apic specific code from genapic_64.c and
move them to their specific genapic files.

[ v2: fix compiling when CONFIG_ACPI is not set ]
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

x2apic Physical mode  support. By default we will use x2apic cluster mode.
x2apic physical mode can be selected using "x2apic_phys" boot parameter.
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>

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>

x2apic cluster mode support.
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 self IPI op for genapic.
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>

Move the read_apic_id()  to genapic routines.
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>

a multi-socket test-system with 3 or 4 ioapics, when 4 dualcore cpus or
2 quadcore cpus installed, needs to switch to bigsmp or physflat.

CPU apic id is [4,11] instead of [0,7], and we need to check max apic
id instead of cpu numbers.

also add check for 32 bit when acpi is not compiled in or acpi=off.
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Don't warn in read_apic_id() when preemptible but only one CPU online.
Signed-off-by: NAndi Kleen <andi@firstfloor.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

cpu_online(), cpu_present(), for_each_possible_cpu(), num_possible_cpus()
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NAlexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NAlexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Yinghai Lu pointed out a bug in the previous patches,
fix double-shift of apicid.
Signed-off-by: NJack Steiner <steiner@sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

UV supports really big systems. So big, in fact, that the APICID register
does not contain enough bits to contain an APICID that is unique across all
cpus.

The UV BIOS supports 3 APICID modes:

	- legacy mode. This mode uses the old APIC mode where
	  APICID is in bits [31:24] of the APICID register.

	- x2apic mode. This mode is whitebox-compatible. APICIDs
	  are unique across all cpus. Standard x2apic APIC operations
	  (Intel-defined) can be used for IPIs. The node identifier
	  fits within the Intel-defined portion of the APICID register.

	- x2apic-uv mode. In this mode, the APICIDs on each node have
	  unique IDs, but IDs on different node are not unique. For example,
	  if each mode has 32 cpus, the APICIDs on each node might be
	  0 - 31. Every node has the same set of IDs.
	  The UV hub is used to route IPIs/interrupts to the correct node.
	  Traditional APIC operations WILL NOT WORK.

In x2apic-uv mode, the ACPI tables all contain a full unique ID (note:
exact bit layout still changing but the following is close):

	nnnnnnnnnnlc0cch
		n = unique node number
		l = socket number on board
		c = core
		h = hyperthread

Only the "lc0cch" bits are written to the APICID register. The remaining bits are
supplied by having the get_apic_id() function "OR" the extra bits into the value
read from the APICID register. (Hmmm.. why not keep the ENTIRE APICID register
in per-cpu data....)

The x2apic-uv mode is recognized by the MADT table containing:
	  oem_id = "SGI"
	  oem_table_id = "UV-X"
Signed-off-by: NJack Steiner <steiner@sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NIngo Molnar <mingo@elte.hu>

Add functions that can be used to determine if an x86_64
system is a SGI "UV" system. UV systems come in 3 types and
are identified by the OEM ID in the MADT.
Signed-off-by: NJack Steiner <steiner@sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Clean up references to x86_cpu_to_apicid.  Removes extraneous
comments and standardizes on "x86_*_early_ptr" for the early
kernel init references.
Signed-off-by: NMike Travis <travis@sgi.com>
Reviewed-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Change the size of APICIDs from u8 to u16.  This partially
supports the new x2apic mode that will be present on future
processor chips. (Chips actually support 32-bit APICIDs, but that
change is more intrusive. Supporting 16-bit is sufficient for now).
Signed-off-by: NJack Steiner <steiner@sgi.com>

I've included just the partial change from u8 to u16 apicids.  The
remaining x2apic changes will be in a separate patch.

In addition, the fake_node_to_pxm_map[] and fake_apicid_to_node[]
tables have been moved from local data to the __initdata section
reducing stack pressure when MAX_NUMNODES and MAX_LOCAL_APIC are
increased in size.
Signed-off-by: NMike Travis <travis@sgi.com>
Reviewed-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>