apic_icr_write() and its users in smpboot.c were apparently
written under the assumption that this code would only run
during early boot. But nowadays we also execute it when onlining
a CPU later on while the system is fully running. That will make
wakeup_cpu_via_init_nmi and, thus, also native_apic_icr_write
run in plain process context. If we migrate the caller to a
different CPU at the wrong time or interrupt it and write to
ICR/ICR2 to send unrelated IPIs, we can end up sending INIT,
SIPI or NMIs to wrong CPUs.

Fix this by disabling interrupts during the write to the ICR
halves and disable preemption around waiting for ICR
availability and using it.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Tested-By: NIgor Mammedov <imammedo@redhat.com>
Link: http://lkml.kernel.org/r/52E6AFFE.3030004@siemens.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

The "nox2apic" variable can be defined as __initdata since it is
only used for bootstrap.  It can now unconditionally be defined
since it will later be freed.

At the same time, it is also better off as a bool.
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1402042354380.7839@chino.kir.corp.google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Make disabled_cpu_apicid static and read_mostly, and fix a couple of
typos.
Reported-by: NIngo Molnar <mingo@kernel.org>
Link: http://lkml.kernel.org/r/20140115182511.GA22737@gmail.comSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>

Add disable_cpu_apicid kernel parameter. To use this kernel parameter,
specify an initial APIC ID of the corresponding CPU you want to
disable.

This is mostly used for the kdump 2nd kernel to disable BSP to wake up
multiple CPUs without causing system reset or hang due to sending INIT
from AP to BSP.

Kdump users first figure out initial APIC ID of the BSP, CPU0 in the
1st kernel, for example from /proc/cpuinfo and then set up this kernel
parameter for the 2nd kernel using the obtained APIC ID.

However, doing this procedure at each boot time manually is awkward,
which should be automatically done by user-land service scripts, for
example, kexec-tools on fedora/RHEL distributions.

This design is more flexible than disabling BSP in kernel boot time
automatically in that in kernel boot time we have no choice but
referring to ACPI/MP table to obtain initial APIC ID for BSP, meaning
that the method is not applicable to the systems without such BIOS
tables.

One assumption behind this design is that users get initial APIC ID of
the BSP in still healthy state and so BSP is uniquely kept in
CPU0. Thus, through the kernel parameter, only one initial APIC ID can
be specified.

In a comparison with disabled_cpu_apicid, we use read_apic_id(), not
boot_cpu_physical_apicid, because on some platforms, the variable is
modified to the apicid reported as BSP through MP table and this
function is executed with the temporarily modified
boot_cpu_physical_apicid. As a result, disabled_cpu_apicid kernel
parameter doesn't work well for apicids of APs.

Fixing the wrong handling of boot_cpu_physical_apicid requires some
reviews and tests beyond some platforms and it could take some
time. The fix here is a kind of workaround to focus on the main topic
of this patch.
Signed-off-by: NHATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Link: http://lkml.kernel.org/r/20140115064458.1545.38775.stgit@localhost6.localdomain6Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Currently we do a read, a dummy write and a final read to fetch
the error code. The value from the final read is taken.
This is not the recommended way and leads to corrupted/lost ESR
values.

Intel(c) 64 and IA-32 Architectures Software Developer's Manual,
Combined Volumes 1, 2ABC, 3ABC, Section 10.5.3 states:

  Before attempt to read from the ESR, software should first
  write to it. (The value written does not affect the values read
  subsequently; only zero may be written in x2APIC mode.) This
  write clears any previously logged errors and updates the ESR
  with any errors detected since the last write to the ESR.
  This write also rearms the APIC error interrupt triggering
  mechanism.

This patch removes the first read such that we are conform with
the manual.

On my (very old) Pentium MMX SMP system this patch fixes the
issue that APIC errors:

  a) are not always reported and
  b) are reported with false error numbers.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Cc: seiji.aguchi@hds.com
Cc: rientjes@google.com
Cc: konrad.wilk@oracle.com
Cc: bp@alien8.de
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1389685487-20872-1-git-send-email-richard@nod.atSigned-off-by: NIngo Molnar <mingo@kernel.org>

Commit 9ebddac7 "ACPI, x86: Fix extended error log driver to depend on
CONFIG_X86_LOCAL_APIC" fixed a build error when CONFIG_X86_LOCAL_APIC was not
selected and !CONFIG_SMP.

However, since CONFIG_ACPI_EXTLOG is tristate, there is a second build error:

  ERROR: "boot_cpu_physical_apicid" [drivers/acpi/acpi_extlog.ko] undefined!

The symbol needs to be exported for it to be available.
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Acked-by: NTony Luck <tony.luck@intel.com>
Cc: Chen Gong <gong.chen@linux.intel.com>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1311141504080.30112@chino.kir.corp.google.com
[ Changed it to a _GPL() export. ]
Signed-off-by: NIngo Molnar <mingo@kernel.org>

In acpi_register_lapic(), it will generates a new logical cpu
number and maps to the local APIC id, this logical cpu number
can be returned to simplify _acpi_map_lsapic() implementation.
Signed-off-by: NJiang Liu <jiang.liu@huawei.com>
Signed-off-by: NHanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

These handlers are all referenced from assembler stubs, so need
to be visible.

The handlers without arguments become asmlinkage, the others __visible
to not force regparms(0) on x86-32.

I put it all into a single patch, please let me know if you want
it it split up.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1375740170-7446-4-git-send-email-andi@firstfloor.orgSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>

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 5e427ec2 ("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.

Note that some harmless section mismatch warnings may result, since
notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c)
are flagged as __cpuinit  -- so if we remove the __cpuinit from
arch specific callers, we will also get section mismatch warnings.
As an intermediate step, we intend to turn the linux/init.h cpuinit
content into no-ops as early as possible, since that will get rid
of these warnings.  In any case, they are temporary and harmless.

This removes all the arch/x86 uses of the __cpuinit macros from
all C files.  x86 only had the one __CPUINIT used in assembly files,
and it wasn't paired off with a .previous or a __FINIT, so we can
delete it directly w/o any corresponding additional change there.

[1] https://lkml.org/lkml/2013/5/20/589

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Acked-by: NIngo Molnar <mingo@kernel.org>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NH. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Compiling without CONFIG_X86_LOCAL_APIC set, apic.c will not be
compiled, and the irq tracepoints will not be created via the
CREATE_TRACE_POINTS macro. When CONFIG_X86_LOCAL_APIC is not set,
we get the following build error:

  LD      init/built-in.o
arch/x86/built-in.o: In function `trace_x86_platform_ipi_entry':
linux-test.git/arch/x86/include/asm/trace/irq_vectors.h:66: undefined reference to `__tracepoint_x86_platform_ipi_entry'
arch/x86/built-in.o: In function `trace_x86_platform_ipi_exit':
linux-test.git/arch/x86/include/asm/trace/irq_vectors.h:66: undefined reference to `__tracepoint_x86_platform_ipi_exit'
arch/x86/built-in.o: In function `trace_irq_work_entry':
linux-test.git/arch/x86/include/asm/trace/irq_vectors.h:72: undefined reference to `__tracepoint_irq_work_entry'
arch/x86/built-in.o: In function `trace_irq_work_exit':
linux-test.git/arch/x86/include/asm/trace/irq_vectors.h:72: undefined reference to `__tracepoint_irq_work_exit'
arch/x86/built-in.o:(__jump_table+0x8): undefined reference to `__tracepoint_x86_platform_ipi_entry'
arch/x86/built-in.o:(__jump_table+0x14): undefined reference to `__tracepoint_x86_platform_ipi_exit'
arch/x86/built-in.o:(__jump_table+0x20): undefined reference to `__tracepoint_irq_work_entry'
arch/x86/built-in.o:(__jump_table+0x2c): undefined reference to `__tracepoint_irq_work_exit'
make[1]: *** [vmlinux] Error 1
make: *** [sub-make] Error 2

As irq.c is always compiled for x86, it is a more appropriate location
to create the irq tracepoints.

Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

[Purpose of this patch]

As Vaibhav explained in the thread below, tracepoints for irq vectors
are useful.

http://www.spinics.net/lists/mm-commits/msg85707.html

<snip>
The current interrupt traces from irq_handler_entry and irq_handler_exit
provide when an interrupt is handled.  They provide good data about when
the system has switched to kernel space and how it affects the currently
running processes.

There are some IRQ vectors which trigger the system into kernel space,
which are not handled in generic IRQ handlers.  Tracing such events gives
us the information about IRQ interaction with other system events.

The trace also tells where the system is spending its time.  We want to
know which cores are handling interrupts and how they are affecting other
processes in the system.  Also, the trace provides information about when
the cores are idle and which interrupts are changing that state.
<snip>

On the other hand, my usecase is tracing just local timer event and
getting a value of instruction pointer.

I suggested to add an argument local timer event to get instruction pointer before.
But there is another way to get it with external module like systemtap.
So, I don't need to add any argument to irq vector tracepoints now.

[Patch Description]

Vaibhav's patch shared a trace point ,irq_vector_entry/irq_vector_exit, in all events.
But there is an above use case to trace specific irq_vector rather than tracing all events.
In this case, we are concerned about overhead due to unwanted events.

So, add following tracepoints instead of introducing irq_vector_entry/exit.
so that we can enable them independently.
   - local_timer_vector
   - reschedule_vector
   - call_function_vector
   - call_function_single_vector
   - irq_work_entry_vector
   - error_apic_vector
   - thermal_apic_vector
   - threshold_apic_vector
   - spurious_apic_vector
   - x86_platform_ipi_vector

Also, introduce a logic switching IDT at enabling/disabling time so that a time penalty
makes a zero when tracepoints are disabled. Detailed explanations are as follows.
 - Create trace irq handlers with entering_irq()/exiting_irq().
 - Create a new IDT, trace_idt_table, at boot time by adding a logic to
   _set_gate(). It is just a copy of original idt table.
 - Register the new handlers for tracpoints to the new IDT by introducing
   macros to alloc_intr_gate() called at registering time of irq_vector handlers.
 - Add checking, whether irq vector tracing is on/off, into load_current_idt().
   This has to be done below debug checking for these reasons.
   - Switching to debug IDT may be kicked while tracing is enabled.
   - On the other hands, switching to trace IDT is kicked only when debugging
     is disabled.

In addition, the new IDT is created only when CONFIG_TRACING is enabled to avoid being
used for other purposes.
Signed-off-by: NSeiji Aguchi <seiji.aguchi@hds.com>
Link: http://lkml.kernel.org/r/51C323ED.5050708@hds.comSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>

When implementing tracepoints in interrupt handers, if the tracepoints are
simply added in the performance sensitive path of interrupt handers,
it may cause potential performance problem due to the time penalty.

To solve the problem, an idea is to prepare non-trace/trace irq handers and
switch their IDTs at the enabling/disabling time.

So, let's introduce entering_irq()/exiting_irq() for pre/post-
processing of each irq handler.

A way to use them is as follows.

Non-trace irq handler:
smp_irq_handler()
{
	entering_irq();		/* pre-processing of this handler */
	__smp_irq_handler();	/*
				 * common logic between non-trace and trace handlers
				 * in a vector.
				 */
	exiting_irq();		/* post-processing of this handler */

}

Trace irq_handler:
smp_trace_irq_handler()
{
	entering_irq();		/* pre-processing of this handler */
	trace_irq_entry();	/* tracepoint for irq entry */
	__smp_irq_handler();	/*
				 * common logic between non-trace and trace handlers
				 * in a vector.
				 */
	trace_irq_exit();	/* tracepoint for irq exit */
	exiting_irq();		/* post-processing of this handler */

}

If tracepoints can place outside entering_irq()/exiting_irq() as follows,
it looks cleaner.

smp_trace_irq_handler()
{
	trace_irq_entry();
	smp_irq_handler();
	trace_irq_exit();
}

But it doesn't work.
The problem is with irq_enter/exit() being called. They must be called before
trace_irq_enter/exit(),  because of the rcu_irq_enter() must be called before
any tracepoints are used, as tracepoints use  rcu to synchronize.

As a possible alternative, we may be able to call irq_enter() first as follows
if irq_enter() can nest.

smp_trace_irq_hander()
{
	irq_entry();
	trace_irq_entry();
	smp_irq_handler();
	trace_irq_exit();
	irq_exit();
}

But it doesn't work, either.
If irq_enter() is nested, it may have a time penalty because it has to check if it
was already called or not. The time penalty is not desired in performance sensitive
paths even if it is tiny.
Signed-off-by: NSeiji Aguchi <seiji.aguchi@hds.com>
Link: http://lkml.kernel.org/r/51C3238D.9040706@hds.comSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>

The Kconfig symbol X86_MCE_P4THERMAL was removed in v2.6.32.
Remove a useless check for its macro, as it will now always
evaluate to false.
Signed-off-by: NPaul Bolle <pebolle@tiscali.nl>
Link: http://lkml.kernel.org/r/1369853850.23034.28.camel@x61.thuisdomeinSigned-off-by: NIngo Molnar <mingo@kernel.org>

Including " lapic " in the kernel cmdline on an x86-64 kernel
makes it panic while parsing early params -- e.g. with no user
visible output.

Fix this bug by ensuring arg is non-NULL before passing it to
strncmp().
Reported-by: NPaX Team <pageexec@freemail.hu>
Signed-off-by: NMathias Krause <minipli@googlemail.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1361303227-13174-1-git-send-email-minipli@googlemail.com
Cc: stable@vger.kernel.org	# v3.8
Signed-off-by: NIngo Molnar <mingo@kernel.org>

IO-APIC and PIC use the same resume routines when IRQ
remapping is enabled or disabled. So it should be safe to
mask the other APICs for the IRQ-remapping-disabled case
too.
Signed-off-by: NJoerg Roedel <joro@8bytes.org>
Acked-by: NSebastian Andrzej Siewior <sebastian@breakpoint.cc>
Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Move the three easy to move checks in the x86' apic.c file
into the IRQ-remapping code.
Signed-off-by: NJoerg Roedel <joro@8bytes.org>
Acked-by: NSebastian Andrzej Siewior <sebastian@breakpoint.cc>
Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

If the TSC deadline mode is supported, LAPIC timer one-shot mode can be
implemented using IA32_TSC_DEADLINE MSR. An interrupt will be generated
when the TSC value equals or exceeds the value in the IA32_TSC_DEADLINE
MSR.

This enables us to skip the APIC calibration during boot. Also, in
xapic mode, this enables us to skip the uncached apic access to re-arm
the APIC timer.

As this timer ticks at the high frequency TSC rate, we use the
TSC_DIVISOR (32) to work with the 32-bit restrictions in the
clockevent API's to avoid 64-bit divides etc (frequency is u32 and
"unsigned long" in the set_next_event(), max_delta limits the next
event to 32-bit for 32-bit kernel).
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: venki@google.com
Cc: len.brown@intel.com
Link: http://lkml.kernel.org/r/1350941878.6017.31.camel@sbsiddha-desk.sc.intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Found by http://coccinelle.lip6.fr/Signed-off-by: NPeter Senna Tschudin <peter.senna@gmail.com>
Cc: avi@redhat.com
Cc: mtosatti@redhat.com
Cc: a.p.zijlstra@chello.nl
Cc: rusty@rustcorp.com.au
Cc: masami.hiramatsu.pt@hitachi.com
Cc: suresh.b.siddha@intel.com
Cc: joerg.roedel@amd.com
Cc: agordeev@redhat.com
Cc: yinghai@kernel.org
Cc: bhelgaas@google.com
Cc: liuj97@gmail.com
Link: http://lkml.kernel.org/r/1347986174-30287-7-git-send-email-peter.senna@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

KVM PV EOI optimization overrides eoi_write apic op with its own
version. Add an API for this to avoid meddling with core x86 apic driver
data structures directly.

For KVM use, we don't need any guarantees about when the switch to the
new op will take place, so it could in theory use this API after SMP init,
but it currently doesn't, and restricting callers to early init makes it
clear that it's safe as it won't race with actual APIC driver use.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Acked-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Signed-off-by: NAlexander Gordeev <agordeev@redhat.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20120614074954.GF3383@dhcp-26-207.brq.redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Since there are only two locations where cpu_mask_to_apicid() is
called from, remove the operation and use only
cpu_mask_to_apicid_and() instead.
Signed-off-by: NAlexander Gordeev <agordeev@redhat.com>
Suggested-and-acked-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Acked-by: NYinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20120614074935.GE3383@dhcp-26-207.brq.redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Add "read-mostly" qualifier to the following variables in
smp.h:

 - cpu_sibling_map
 - cpu_core_map
 - cpu_llc_shared_map
 - cpu_llc_id
 - cpu_number
 - x86_cpu_to_apicid
 - x86_bios_cpu_apicid
 - x86_cpu_to_logical_apicid

As long as all the variables above are only written during the
initialization, this change is meant to prevent the false
sharing. More specifically, on vSMP Foundation platform
x86_cpu_to_apicid shared the same internode_cache_line with
frequently written lapic_events.

From the analysis of the first 33 per_cpu variables out of 219
(memories they describe, to be more specific) the 8 have read_mostly
nature (tlb_vector_offset, cpu_loops_per_jiffy, xen_debug_irq, etc.)
and 25 are frequently written (irq_stack_union, gdt_page,
exception_stacks, idt_desc, etc.).

Assuming that the spread of the rest of the per_cpu variables is
similar, identifying the read mostly memories will make more sense
in terms of long-term code maintenance comparing to identifying
frequently written memories.
Signed-off-by: NVlad Zolotarov <vlad@scalemp.com>
Acked-by: NShai Fultheim <shai@scalemp.com>
Cc: Shai Fultheim (Shai@ScaleMP.com) <Shai@scalemp.com>
Cc: ido@wizery.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1719258.EYKzE4Zbq5@vladSigned-off-by: NIngo Molnar <mingo@kernel.org>

Currently cpu_mask_to_apicid() should not get a offline CPU with
the cpumask. Otherwise some apic drivers might try to access
non-existent per-cpu variables (i.e. x2apic). In that regard
cpu_mask_to_apicid() and cpu_mask_to_apicid_and() operations are
inconsistent.

This fix makes the two operations do not rely on calling
functions and always return the apicid for only online CPUs. As
result, the meaning and implementations of cpu_mask_to_apicid()
and cpu_mask_to_apicid_and() operations become straight.
Signed-off-by: NAlexander Gordeev <agordeev@redhat.com>
Acked-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20120607131624.GG4759@dhcp-26-207.brq.redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Current cpu_mask_to_apicid() and cpu_mask_to_apicid_and()
implementations have few shortcomings:

1. A value returned by cpu_mask_to_apicid() is written to
hardware registers unconditionally. Should BAD_APICID get ever
returned it will be written to a hardware too. But the value of
BAD_APICID is not universal across all hardware in all modes and
might cause unexpected results, i.e. interrupts might get routed
to CPUs that are not configured to receive it.

2. Because the value of BAD_APICID is not universal it is
counter- intuitive to return it for a hardware where it does not
make sense (i.e. x2apic).

3. cpu_mask_to_apicid_and() operation is thought as an
complement to cpu_mask_to_apicid() that only applies a AND mask
on top of a cpumask being passed. Yet, as consequence of 18374d89
commit the two operations are inconsistent in that of:
  cpu_mask_to_apicid() should not get a offline CPU with the cpumask
  cpu_mask_to_apicid_and() should not fail and return BAD_APICID
These limitations are impossible to realize just from looking at
the operations prototypes.

Most of these shortcomings are resolved by returning a error
code instead of BAD_APICID. As the result, faults are reported
back early rather than possibilities to cause a unexpected
behaviour exist (in case of [1]).

The only exception is setup_timer_IRQ0_pin() routine. Although
obviously controversial to this fix, its existing behaviour is
preserved to not break the fragile check_timer() and would
better addressed in a separate fix.
Signed-off-by: NAlexander Gordeev <agordeev@redhat.com>
Acked-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20120607131559.GF4759@dhcp-26-207.brq.redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Signed-off-by: NAlexander Gordeev <agordeev@redhat.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20120605112340.GA11454@dhcp-26-207.brq.redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

On virtual environments, apic_read could take a long time. As a
result, under certain conditions the ack pending loop may exit
without any queued irqs left, but after more than one second. A
warning will be printed needlessly in this case.

If the loop is about to exit regardless of max_loops, don't
update it.
Signed-off-by: NShai Fultheim <shai@scalemp.com>
[ rebased and reworded the commit message]
Signed-off-by: NIdo Yariv <ido@wizery.com>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1334873552-31346-1-git-send-email-ido@wizery.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Make the file names consistent with the naming conventions of irq subsystem.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: Joerg Roedel <joerg.roedel@amd.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

Make the code consistent with the naming conventions of irq subsystem.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: Joerg Roedel <joerg.roedel@amd.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

Convert these calls too:

	* Disable of remapping hardware
	* Reenable of remapping hardware
	* Enable fault handling

With that all of arch/x86/kernel/apic/apic.c is converted to
use the generic intr-remapping interface.
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>
Acked-by: NYinghai Lu <yinghai@kernel.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

This patch introduces irq_remap_ops to hold implementation
specific function pointer to handle interrupt remapping. As
the first part the initialization functions for VT-d are
converted to these ops.
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>
Acked-by: NYinghai Lu <yinghai@kernel.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

Current APIC code assumes MSR_IA32_APICBASE is present for all systems.
Pentium Classic P5 and friends didn't have this MSR. MSR_IA32_APICBASE
was introduced as an architectural MSR by Intel @ P6.

Code paths that can touch this MSR invalidly are when vendor == Intel &&
cpu-family == 5 and APIC bit is set in CPUID - or when you simply pass
lapic on the kernel command line, on a P5.

The below patch stops Linux incorrectly interfering with the
MSR_IA32_APICBASE for P5 class machines. Other code paths exist that
touch the MSR - however those paths are not currently reachable for a
conformant P5.
Signed-off-by: NBryan O'Donoghue <bryan.odonoghue@linux.intel.com>
Link: http://lkml.kernel.org/r/4F8EEDD3.1080404@linux.intel.comSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>
Cc: <stable@vger.kernel.org>

Add information about LVT offset assignments to better debug firmware
bugs related to this. See following examples.

 # dmesg | grep -i 'offset\|ibs'
 LVT offset 0 assigned for vector 0xf9
 [Firmware Bug]: cpu 0, try to use APIC500 (LVT offset 0) for vector 0x10400, but the register is already in use for vector 0xf9 on another cpu
 [Firmware Bug]: cpu 0, IBS interrupt offset 0 not available (MSRC001103A=0x0000000000000100)
 Failed to setup IBS, -22

In this case the BIOS assigns both offsets for MCE (0xf9) and IBS
(0x400) vectors to offset 0, which is why the second APIC setup (IBS)
failed.

With correct setup you get:

 # dmesg | grep -i 'offset\|ibs'
 LVT offset 0 assigned for vector 0xf9
 LVT offset 1 assigned for vector 0x400
 IBS: LVT offset 1 assigned
 perf: AMD IBS detected (0x00000007)
 oprofile: AMD IBS detected (0x00000007)

Note: The vector includes also the message type to handle also NMIs
(0x400). In the firmware bug message the format is the same as of the
APIC500 register and includes the mask bit (bit 16) in addition.
Signed-off-by: NRobert Richter <robert.richter@amd.com>
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Currently "nox2apic" boot parameter was not enabling x2apic mode if the cpu,
kernel are all capable of enabling x2apic mode and the OS handover
happened in xapic mode.

However If the bios enabled x2apic prior to OS handover, using "nox2apic"
boot parameter had no effect.

If the boot cpu's apicid is < 255, enable "nox2apic" boot parameter to
disable the x2apic mode setup by the bios. This will enable the kernel to
fallback to xapic mode and bringup only the cpu's which has apic-id < 255.

-v2: fix patch error and two compiling warning
	make disable_x2apic to be __init
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/CAE9FiQUeB-3uxJAMiHsz=uPWoFv5Hg1pVepz7aU6YtqOxMC-=Q@mail.gmail.comSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>

On some of the recent Intel SNB platforms, by default bios is pre-enabling
x2apic mode in the cpu with out setting up interrupt-remapping.
This case was resulting in the kernel to panic as the cpu is already in
x2apic mode but the OS was not able to enable interrupt-remapping (which
is a pre-req for using x2apic capability).

On these platforms all the apic-ids are < 255 and the kernel can fallback to
xapic mode if the bios has not enabled interrupt-remapping (which is
mostly the case if the bios has not exported interrupt-remapping tables to the
OS).
Reported-by: NBerck E. Nash <flyboy@gmail.com>
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20111222014632.600418637@sbsiddha-desk.sc.intel.comSigned-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

LAPIC related statistics are grouped inside the per-cpu
structure irq_stat, so there is no need for icr_read_retry_count
to be a standalone per-cpu variable.

This patch moves icr_read_retry_count to where it belongs.

Suggested-y: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NFernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Cc: Jörn Engel <joern@logfs.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

In the IPI delivery slow path (NMI delivery) we retry the ICR
read to check for delivery completion a limited number of times.

[ The reason for the limited retries is that some of the places
  where it is used (cpu boot, kdump, etc) IPI delivery might not
  succeed (due to a firmware bug or system crash, for example)
  and in such a case it is better to give up and resume
  execution of other code. ]

This patch adds a new entry to /proc/interrupts, RTR, which
tells user space the number of times we retried the ICR read in
the IPI delivery slow path.

This should give some insight into how well the APIC
message delivery hardware is working - if the counts are way
too large then we are hitting a (very-) slow path way too
often.
Signed-off-by: NFernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Cc: Jörn Engel <joern@logfs.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/n/tip-vzsp20lo2xdzh5f70g0eis2s@git.kernel.org
[ extended the changelog ]
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Interrupts notify the idle exit state before calling irq_enter().
But the notifier code calls rcu_read_lock() and this is not
allowed while rcu is in an extended quiescent state. We need
to wait for irq_enter() -> rcu_idle_exit() to be called before
doing so otherwise this results in a grumpy RCU:

[    0.099991] WARNING: at include/linux/rcupdate.h:194 __atomic_notifier_call_chain+0xd2/0x110()
[    0.099991] Hardware name: AMD690VM-FMH
[    0.099991] Modules linked in:
[    0.099991] Pid: 0, comm: swapper Not tainted 3.0.0-rc6+ #255
[    0.099991] Call Trace:
[    0.099991]  <IRQ>  [<ffffffff81051c8a>] warn_slowpath_common+0x7a/0xb0
[    0.099991]  [<ffffffff81051cd5>] warn_slowpath_null+0x15/0x20
[    0.099991]  [<ffffffff817d6fa2>] __atomic_notifier_call_chain+0xd2/0x110
[    0.099991]  [<ffffffff817d6ff1>] atomic_notifier_call_chain+0x11/0x20
[    0.099991]  [<ffffffff81001873>] exit_idle+0x43/0x50
[    0.099991]  [<ffffffff81020439>] smp_apic_timer_interrupt+0x39/0xa0
[    0.099991]  [<ffffffff817da253>] apic_timer_interrupt+0x13/0x20
[    0.099991]  <EOI>  [<ffffffff8100ae67>] ? default_idle+0xa7/0x350
[    0.099991]  [<ffffffff8100ae65>] ? default_idle+0xa5/0x350
[    0.099991]  [<ffffffff8100b19b>] amd_e400_idle+0x8b/0x110
[    0.099991]  [<ffffffff810cb01f>] ? rcu_enter_nohz+0x8f/0x160
[    0.099991]  [<ffffffff810019a0>] cpu_idle+0xb0/0x110
[    0.099991]  [<ffffffff817a7505>] rest_init+0xe5/0x140
[    0.099991]  [<ffffffff817a7468>] ? rest_init+0x48/0x140
[    0.099991]  [<ffffffff81cc5ca3>] start_kernel+0x3d1/0x3dc
[    0.099991]  [<ffffffff81cc5321>] x86_64_start_reservations+0x131/0x135
[    0.099991]  [<ffffffff81cc5412>] x86_64_start_kernel+0xed/0xf4
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Andy Henroid <andrew.d.henroid@intel.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>

lapic timer calibration can be combined with tsc in platform
specific calibration functions. if such calibration result is
obtained early, we can skip the redundant calibration loops.
Signed-off-by: NJacob Pan <jacob.jun.pan@intel.com>
Signed-off-by: NJacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NDirk Brandewie <dirk.brandewie@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Change the CONFIG_DMAR to CONFIG_INTEL_IOMMU to be consistent
with the other IOMMU options.

Rename the CONFIG_INTR_REMAP to CONFIG_IRQ_REMAP to match the
irq subsystem name.

And define the CONFIG_DMAR_TABLE for the common ACPI DMAR
routines shared by both CONFIG_INTEL_IOMMU and CONFIG_IRQ_REMAP.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: yinghai@kernel.org
Cc: youquan.song@intel.com
Cc: joerg.roedel@amd.com
Cc: tony.luck@intel.com
Cc: dwmw2@infradead.org
Link: http://lkml.kernel.org/r/20110824001456.558630224@sbsiddha-desk.sc.intel.comSigned-off-by: NIngo Molnar <mingo@elte.hu>

On the platforms which are x2apic and interrupt-remapping
capable, Linux kernel is enabling x2apic even if the BIOS
doesn't. This is to take advantage of the features that x2apic
brings in.

Some of the OEM platforms are running into issues because of
this, as their bios is not x2apic aware. For example, this was
resulting in interrupt migration issues on one of the platforms.
Also if the BIOS SMI handling uses APIC interface to send SMI's,
then the BIOS need to be aware of x2apic mode that OS has
enabled.

On some of these platforms, BIOS doesn't have a HW mechanism to
turnoff the x2apic feature to prevent OS from enabling it.

To resolve this mess, recent changes to the VT-d2 specification:

 http://download.intel.com/technology/computing/vptech/Intel(r)_VT_for_Direct_IO.pdf

includes a mechanism that provides BIOS a way to request system
software to opt out of enabling x2apic mode.

Look at the x2apic optout flag in the DMAR tables before
enabling the x2apic mode in the platform. Also print a warning
that we have disabled x2apic based on the BIOS request.

Kernel boot parameter "intremap=no_x2apic_optout" can be used to
override the BIOS x2apic optout request.
Signed-off-by: NYouquan Song <youquan.song@intel.com>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: yinghai@kernel.org
Cc: joerg.roedel@amd.com
Cc: tony.luck@intel.com
Cc: dwmw2@infradead.org
Link: http://lkml.kernel.org/r/20110824001456.171766616@sbsiddha-desk.sc.intel.comSigned-off-by: NIngo Molnar <mingo@elte.hu>