x86: replace CONFIG_HAVE_KVM with IS_ENABLED(CONFIG_KVM)

It is more accurate to check if KVM is enabled, instead of having the
architecture say so. Architectures always "have" KVM, so for example
checking CONFIG_HAVE_KVM in x86 code is pointless, but if KVM is disabled
in a specific build, there is no need for support code.

Alternatively, many of the #ifdefs could simply be deleted. However,
this would add completely dead code. For example, when KVM is disabled,
there should not be any posted interrupts, i.e. NOT wiring up the "dummy"
handlers and treating IRQs on those vectors as spurious is the right
thing to do.

Cc: x86@kernel.org
Cc: kbingham@kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

x86/apic: Nuke ack_APIC_irq()

Yet another wrapper of a wrapper gone along with the outdated comment
that this compiles to a single instruction.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Wei Liu <wei.liu@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/irq: Add hardcoded hypervisor interrupts to /proc/stat

Some hypervisor interrupts (such as for Hyper-V VMbus and Hyper-V timers)
have hardcoded interrupt vectors on x86 and don't have Linux IRQs assigned.
These interrupts are shown in /proc/interrupts, but are not reported in
the first field of the "intr" line in /proc/stat because the x86 version
of arch_irq_stat_cpu() doesn't include them.

Fix this by adding code to arch_irq_stat_cpu() to include these interrupts,
similar to existing interrupts that don't have Linux IRQs.

Use #if IS_ENABLED() because unlike all the other nearby #ifdefs,
CONFIG_HYPERV can be built as a module.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/1677523568-50263-1-git-send-email-mikelley%40microsoft.com

x86/irq: Ensure PI wakeup handler is unregistered before module unload

Add a synchronize_rcu() after clearing the posted interrupt wakeup handler
to ensure all readers, i.e. in-flight IRQ handlers, see the new handler
before returning to the caller. If the caller is an exiting module and
is unregistering its handler, failure to wait could result in the IRQ
handler jumping into an unloaded module.

The registration path doesn't require synchronization, as it's the
caller's responsibility to not generate interrupts it cares about until
after its handler is registered.

Fixes: f6b3c72c2366 ("x86/irq: Define a global vector for VT-d Posted-Interrupts")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211009001107.3936588-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

x86: Fix various typos in comments

Fix ~144 single-word typos in arch/x86/ code comments.

Doing this in a single commit should reduce the churn.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-kernel@vger.kernel.org

x86/entry: Convert device interrupts to inline stack switching

Convert device interrupts to inline stack switching by replacing the
existing macro implementation with the new inline version. Tweak the
function signature of the actual handler function to have the vector
argument as u32. That allows the inline macro to avoid extra intermediates
and lets the compiler be smarter about the whole thing.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210210002512.769728139@linutronix.de

thermal: Move therm_throt there from x86/mce

This functionality has nothing to do with MCE, move it to the thermal
framework and untangle it from MCE.

Requested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Tested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Link: https://lkml.kernel.org/r/20210202121003.GD18075@zn.tnic

x86/irq: Make run_on_irqstack_cond() typesafe

Sami reported that run_on_irqstack_cond() requires the caller to cast
functions to mismatching types, which trips indirect call Control-Flow
Integrity (CFI) in Clang.

Instead of disabling CFI on that function, provide proper helpers for
the three call variants. The actual ASM code stays the same as that is
out of reach.

[ bp: Fix __run_on_irqstack() prototype to match. ]

Fixes: 931b94145981 ("x86/entry: Provide helpers for executing on the irqstack")
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Reported-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Cc: <stable@vger.kernel.org>
Link: https://github.com/ClangBuiltLinux/linux/issues/1052
Link: https://lkml.kernel.org/r/87pn6eb5tv.fsf@nanos.tec.linutronix.de

x86/entry: Convert KVM vectors to IDTENTRY_SYSVEC*

Convert KVM specific system vectors to IDTENTRY_SYSVEC*:

The two empty stub handlers which only increment the stats counter do no
need to run on the interrupt stack. Use IDTENTRY_SYSVEC_SIMPLE for them.

The wakeup handler does more work and runs on the interrupt stack.

None of these handlers need to save and restore the irq_regs pointer.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20200521202119.555715519@linutronix.de

x86/entry: Convert APIC interrupts to IDTENTRY_SYSVEC

Convert APIC interrupts to IDTENTRY_SYSVEC:

- Implement the C entry point with DEFINE_IDTENTRY_SYSVEC
- Emit the ASM stub with DECLARE_IDTENTRY_SYSVEC
- Remove the ASM idtentries in 64-bit
- Remove the BUILD_INTERRUPT entries in 32-bit
- Remove the old prototypes

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20200521202119.280728850@linutronix.de

x86/entry: Use idtentry for interrupts

Replace the extra interrupt handling code and reuse the existing idtentry
machinery. This moves the irq stack switching on 64-bit from ASM to C code;
32-bit already does the stack switching in C.

This requires to remove HAVE_IRQ_EXIT_ON_IRQ_STACK as the stack switch is
not longer in the low level entry code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20200521202119.078690991@linutronix.de

x86/irq: Rework handle_irq() for 64-bit

To consolidate the interrupt entry/exit code vs. the other exceptions
make handle_irq() an inline and handle both 64-bit and 32-bit mode.

Preparatory change to move irq stack switching for 64-bit to C which allows
to consolidate the entry exit handling by reusing the idtentry machinery
both in ASM and C.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20200521202118.889972748@linutronix.de

x86/irq: Convey vector as argument and not in ptregs

Device interrupts which go through do_IRQ() or the spurious interrupt
handler have their separate entry code on 64 bit for no good reason.

Both 32 and 64 bit transport the vector number through ORIG_[RE]AX in
pt_regs. Further the vector number is forced to fit into an u8 and is
complemented and offset by 0x80 so it's in the signed character
range. Otherwise GAS would expand the pushq to a 5 byte instruction for any
vector > 0x7F.

Treat the vector number like an error code and hand it to the C function as
argument. This allows to get rid of the extra entry code in a later step.

Simplify the error code push magic by implementing the pushq imm8 via a
'.byte 0x6a, vector' sequence so GAS is not able to screw it up. As the
pushq imm8 is sign extending the resulting error code needs to be truncated
to 8 bits in C code.

Originally-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20200521202118.796915981@linutronix.de

x86/irq: Use generic irq_regs implementation

The only difference is the name of the per-CPU variable: irq_regs
vs. __irq_regs, but the accessor functions are identical.

Remove the pointless copy and use the generic variant.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20200521202118.704169051@linutronix.de

x86/irq: Remove useless return value from do_IRQ()

Nothing is using it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200225220216.826870369@linutronix.de

x86/irq: Check for VECTOR_UNUSED directly

It's simpler and more intuitive to directly check for VECTOR_UNUSED than
checking whether the other error codes are not set.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/caeaca93-5ee1-cea1-8894-3aa0d5b19241@gmail.com

x86/irq: Move IS_ERR_OR_NULL() check into common do_IRQ() code

Both the 64bit and the 32bit handle_irq() implementation check the irq
descriptor pointer with IS_ERR_OR_NULL() and return failure. That can be
done simpler in the common do_IRQ() code.

This reduces the 64bit handle_irq() function to a wrapper around
generic_handle_irq_desc(). Invoke it directly from do_IRQ() to spare the
extra function call.

[ tglx: Got rid of the #ifdef and massaged changelog ]

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/2ec758c7-9aaa-73ab-f083-cc44c86aa741@gmail.com

x86/irq: Handle spurious interrupt after shutdown gracefully

Since the rework of the vector management, warnings about spurious
interrupts have been reported. Robert provided some more information and
did an initial analysis. The following situation leads to these warnings:

CPU 0 CPU 1 IO_APIC

interrupt is raised
sent to CPU1
Unable to handle
immediately
(interrupts off,
deep idle delay)
mask()
...
free()
shutdown()
synchronize_irq()
clear_vector()
do_IRQ()
-> vector is clear

Before the rework the vector entries of legacy interrupts were statically
assigned and occupied precious vector space while most of them were
unused. Due to that the above situation was handled silently because the
vector was handled and the core handler of the assigned interrupt
descriptor noticed that it is shut down and returned.

While this has been usually observed with legacy interrupts, this situation
is not limited to them. Any other interrupt source, e.g. MSI, can cause the
same issue.

After adding proper synchronization for level triggered interrupts, this
can only happen for edge triggered interrupts where the IO-APIC obviously
cannot provide information about interrupts in flight.

While the spurious warning is actually harmless in this case it worries
users and driver developers.

Handle it gracefully by marking the vector entry as VECTOR_SHUTDOWN instead
of VECTOR_UNUSED when the vector is freed up.

If that above late handling happens the spurious detector will not complain
and switch the entry to VECTOR_UNUSED. Any subsequent spurious interrupt on
that line will trigger the spurious warning as before.

Fixes: 464d12309e1b ("x86/vector: Switch IOAPIC to global reservation mode")
Reported-by: Robert Hodaszi <Robert.Hodaszi@digi.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>-
Tested-by: Robert Hodaszi <Robert.Hodaszi@digi.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Link: https://lkml.kernel.org/r/20190628111440.459647741@linutronix.de

x86/Kconfig: Add new X86_HV_CALLBACK_VECTOR config symbol

Add a special Kconfig symbol X86_HV_CALLBACK_VECTOR so that the guests
using the hypervisor interrupt callback counter can select and thus
enable that counter. Select it when xen or hyperv support is enabled. No
functional changes.

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: linux-hyperv@vger.kernel.org
Cc: Nicolai Stange <nstange@suse.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Cc: xen-devel@lists.xenproject.org
Link: https://lkml.kernel.org/r/1559108037-18813-2-git-send-email-yakui.zhao@intel.com

treewide: Add SPDX license identifier for missed files

Add SPDX license identifiers to all files which:

- Have no license information of any form

- Have EXPORT_.*_SYMBOL_GPL inside which was used in the
initial scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

x86: Don't include linux/irq.h from asm/hardirq.h

The next patch in this series will have to make the definition of
irq_cpustat_t available to entering_irq().

Inclusion of asm/hardirq.h into asm/apic.h would cause circular header
dependencies like

asm/smp.h
asm/apic.h
asm/hardirq.h
linux/irq.h
linux/topology.h
linux/smp.h
asm/smp.h

or

linux/gfp.h
linux/mmzone.h
asm/mmzone.h
asm/mmzone_64.h
asm/smp.h
asm/apic.h
asm/hardirq.h
linux/irq.h
linux/irqdesc.h
linux/kobject.h
linux/sysfs.h
linux/kernfs.h
linux/idr.h
linux/gfp.h

and others.

This causes compilation errors because of the header guards becoming
effective in the second inclusion: symbols/macros that had been defined
before wouldn't be available to intermediate headers in the #include chain
anymore.

A possible workaround would be to move the definition of irq_cpustat_t
into its own header and include that from both, asm/hardirq.h and
asm/apic.h.

However, this wouldn't solve the real problem, namely asm/harirq.h
unnecessarily pulling in all the linux/irq.h cruft: nothing in
asm/hardirq.h itself requires it. Also, note that there are some other
archs, like e.g. arm64, which don't have that #include in their
asm/hardirq.h.

Remove the linux/irq.h #include from x86' asm/hardirq.h.

Fix resulting compilation errors by adding appropriate #includes to *.c
files as needed.

Note that some of these *.c files could be cleaned up a bit wrt. to their
set of #includes, but that should better be done from separate patches, if
at all.

Signed-off-by: Nicolai Stange <nstange@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Drivers: hv: vmbus: Implement Direct Mode for stimer0

The 2016 version of Hyper-V offers the option to operate the guest VM
per-vcpu stimer's in Direct Mode, which means the timer interupts on its
own vector rather than queueing a VMbus message. Direct Mode reduces
timer processing overhead in both the hypervisor and the guest, and
avoids having timer interrupts pollute the VMbus interrupt stream for
the synthetic NIC and storage. This patch enables Direct Mode by
default on stimer0 when running on a version of Hyper-V that supports
it.

In prep for coming support of Hyper-V on ARM64, the arch independent
portion of the code contains calls to routines that will be populated
on ARM64 but are not needed and do nothing on x86.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

x86/irq: Count Hyper-V reenlightenment interrupts

Hyper-V reenlightenment interrupts arrive when the VM is migrated, While
they are not interesting in general it's important when L2 nested guests
are running.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: kvm@vger.kernel.org
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: "Michael Kelley (EOSG)" <Michael.H.Kelley@microsoft.com>
Cc: Roman Kagan <rkagan@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: devel@linuxdriverproject.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Cathy Avery <cavery@redhat.com>
Cc: Mohammed Gamal <mmorsy@redhat.com>
Link: https://lkml.kernel.org/r/20180124132337.30138-6-vkuznets@redhat.com

x86/irq: Remove an old outdated comment about context tracking races

That race has been fixed and code cleaned up for a while now.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Link: https://lkml.kernel.org/r/20171204150605.150551639@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/irq: Simplify hotplug vector accounting

Before a CPU is taken offline the number of active interrupt vectors on the
outgoing CPU and the number of vectors which are available on the other
online CPUs are counted and compared. If the active vectors are more than
the available vectors on the other CPUs then the CPU hot-unplug operation
is aborted. This again uses loop based search and is inaccurate.

The bitmap matrix allocator has accurate accounting information and can
tell exactly whether the vector space is sufficient or not.

Emit a message when the number of globaly reserved (unallocated) vectors is
larger than the number of available vectors after offlining a CPU because
after that point request_irq() might fail.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Yu Chen <yu.c.chen@intel.com>
Acked-by: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rui Zhang <rui.zhang@intel.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Len Brown <lenb@kernel.org>
Link: https://lkml.kernel.org/r/20170913213156.351193962@linutronix.de

x86/vector: Rename used_vectors to system_vectors

used_vectors is a nisnomer as it only has the system vectors which are
excluded from the regular vector allocation marked. It's not what the name
suggests storage for the actually used vectors.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Yu Chen <yu.c.chen@intel.com>
Acked-by: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rui Zhang <rui.zhang@intel.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Len Brown <lenb@kernel.org>
Link: https://lkml.kernel.org/r/20170913213154.150209009@linutronix.de

x86/ipi: Make platform IPI depend on APIC

The platform IPI vector is only installed when the local APIC is enabled. All
users of it depend on the local APIC anyway.

Make the related code conditional on CONFIG_X86_LOCAL_APIC=y.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170828064957.615286163@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/irq: Get rid of duplicated trace_x86_platform_ipi() code

Two NOP5s are really a good tradeoff vs. the unholy IDT switching mess,
which duplicates code all over the place.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170828064956.907209383@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/irq: Get rid of the 'first_system_vector' indirection bogosity

This variable is beyond pointless. Nothing allocates a vector via
alloc_gate() below FIRST_SYSTEM_VECTOR. So nothing can change
first_system_vector.

If there is a need for a gate below FIRST_SYSTEM_VECTOR then it can be
added to the vector defines and FIRST_SYSTEM_VECTOR can be adjusted
accordingly.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170828064956.357109735@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/irq: Remove vector_used_by_percpu_irq()

Last user (lguest) is gone. Remove it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170828064956.201432430@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86: irq: Define a global vector for nested posted interrupts

We are using the same vector for nested/non-nested posted
interrupts delivery, this may cause interrupts latency in
L1 since we can't kick the L2 vcpu out of vmx-nonroot mode.

This patch introduces a new vector which is only for nested
posted interrupts to solve the problems above.

Signed-off-by: Wincy Van <fanwenyi0529@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

x86/irq: Use irq_migrate_all_off_this_cpu()

The generic migration code supports all the required features
already. Remove the x86 specific implementation and use the generic one.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20170619235445.851311033@linutronix.de

x86/irq: Restructure fixup_irqs()

Reorder fixup_irqs() so it matches the flow in the generic migration code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20170619235445.774272454@linutronix.de

x86/irq: Cleanup pending irq move in fixup_irqs()

If an CPU goes offline, the interrupts are migrated away, but a eventually
pending interrupt move, which has not yet been made effective is kept
pending even if the outgoing CPU is the sole target of the pending affinity
mask. What's worse is, that the pending affinity mask is discarded even if
it would contain a valid subset of the online CPUs.

Use the newly introduced helper to:

- Discard a pending move when the outgoing CPU is the only target in the
pending mask.

- Use the pending mask instead of the affinity mask to find a valid target
for the CPU if the pending mask intersects with the online CPUs.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20170619235444.774068557@linutronix.de

x86/irq: Optimize free vector check in the CPU offline path

Before offlining a CPU its required to check whether there are enough free
irq vectors available so interrupts can be migrated away from the CPU.

This check is executed whether its required or not and neither stops
searching when the number of required free vectors are reached.

Bypass the free vector check if the current CPU has no irq to migrate and
leave the for_each_online_cpu() loop when the free vector count reaches the
number of required vectors.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Len Brown <lenb@kernel.orq>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Link: http://lkml.kernel.org/r/1492357410-510-1-git-send-email-yu.c.chen@intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/irq, trace: Add __irq_entry annotation to x86's platform IRQ handlers

This patch adds the __irq_entry annotation to the default x86
platform IRQ handlers. ftrace's function_graph tracer uses the
__irq_entry annotation to notify the entry and return of IRQ
handlers.

For example, before the patch:
354549.667252 | 3) d..1 | default_idle_call() {
354549.667252 | 3) d..1 | arch_cpu_idle() {
354549.667253 | 3) d..1 | default_idle() {
354549.696886 | 3) d..1 | smp_trace_reschedule_interrupt() {
354549.696886 | 3) d..1 | irq_enter() {
354549.696886 | 3) d..1 | rcu_irq_enter() {

After the patch:
366416.254476 | 3) d..1 | arch_cpu_idle() {
366416.254476 | 3) d..1 | default_idle() {
366416.261566 | 3) d..1 ==========> |
366416.261566 | 3) d..1 | smp_trace_reschedule_interrupt() {
366416.261566 | 3) d..1 | irq_enter() {
366416.261566 | 3) d..1 | rcu_irq_enter() {

KASAN also uses this annotation. The smp_apic_timer_interrupt()
was already annotated.

Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Claudio Fontana <claudio.fontana@huawei.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nicolai Stange <nicstange@gmail.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: linux-edac@vger.kernel.org
Link: http://lkml.kernel.org/r/059fdf437c2f0c09b13c18c8fe4e69999d3ffe69.1483528431.git.bristot@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86: Remove empty idle.h header

One include less is always a good thing(tm). Good riddance.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20161209182912.2726-6-bp@alien8.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/irq: Do not substract irq_tlb_count from irq_call_count

Since commit:

52aec3308db8 ("x86/tlb: replace INVALIDATE_TLB_VECTOR by CALL_FUNCTION_VECTOR")

the TLB remote shootdown is done through call function vector. That
commit didn't take care of irq_tlb_count, which a later commit:

fd0f5869724f ("x86: Distinguish TLB shootdown interrupts from other functions call interrupts")

... tried to fix.

The fix assumes every increase of irq_tlb_count has a corresponding
increase of irq_call_count. So the irq_call_count is always bigger than
irq_tlb_count and we could substract irq_tlb_count from irq_call_count.

Unfortunately this is not true for the smp_call_function_single() case.
The IPI is only sent if the target CPU's call_single_queue is empty when
adding a csd into it in generic_exec_single. That means if two threads
are both adding flush tlb csds to the same CPU's call_single_queue, only
one IPI is sent. In other words, the irq_call_count is incremented by 1
but irq_tlb_count is incremented by 2. Over time, irq_tlb_count will be
bigger than irq_call_count and the substract will produce a very large
irq_call_count value due to overflow.

Considering that:

1) it's not worth to send more IPIs for the sake of accurate counting of
irq_call_count in generic_exec_single();

2) it's not easy to tell if the call function interrupt is for TLB
shootdown in __smp_call_function_single_interrupt().

Not to exclude TLB shootdown from call function count seems to be the
simplest fix and this patch just does that.

This bug was found by LKP's cyclic performance regression tracking recently
with the vm-scalability test suite. I have bisected to commit:

3dec0ba0be6a ("mm/rmap: share the i_mmap_rwsem")

This commit didn't do anything wrong but revealed the irq_call_count
problem. IIUC, the commit makes rwc->remap_one in rmap_walk_file
concurrent with multiple threads. When remap_one is try_to_unmap_one(),
then multiple threads could queue flush TLB to the same CPU but only
one IPI will be sent.

Since the commit was added in Linux v3.19, the counting problem only
shows up from v3.19 onwards.

Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Cc: Alex Shi <alex.shi@linaro.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com>
Link: http://lkml.kernel.org/r/20160811074430.GA18163@aaronlu.sh.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/irq: Call irq_force_move_complete with irq descriptor

First of all there is no point in looking up the irq descriptor again, but we
also need the descriptor for the final cleanup race fix in the next
patch. Make that change seperate. No functional difference.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Borislav Petkov <bp@alien8.de>
Tested-by: Joe Lawrence <joe.lawrence@stratus.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Jeremiah Mahler <jmmahler@gmail.com>
Cc: andy.shevchenko@gmail.com
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: stable@vger.kernel.org #4.3+
Link: http://lkml.kernel.org/r/20151231160107.125211743@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/irq: Validate that irq descriptor is still active

In fixup_irqs() we unconditionally dereference the irq chip of an irq
descriptor. The descriptor might still be valid, but already cleaned up,
i.e. the chip removed. Add a check for this condition.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joe Lawrence <joe.lawrence@stratus.com>
Cc: Jeremiah Mahler <jmmahler@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: andy.shevchenko@gmail.com
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: stable@vger.kernel.org #4.3+
Link: http://lkml.kernel.org/r/20151231160106.236423282@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/irq: Store irq descriptor in vector array

We can spare the irq_desc lookup in the interrupt entry code if we
store the descriptor pointer in the vector array instead the interrupt
number.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Link: http://lkml.kernel.org/r/20150802203609.717724106@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/irq: Get rid of an indentation level

Make the code simpler to read.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Link: http://lkml.kernel.org/r/20150802203609.555253675@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/irq: Rename VECTOR_UNDEFINED to VECTOR_UNUSED

VECTOR_UNDEFINED is a misnomer. The vector is defined, but unused.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Link: http://lkml.kernel.org/r/20150802203609.477282494@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/irq: Replace numeric constant

Use the proper define instead of 0.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Link: http://lkml.kernel.org/r/20150802203609.385495420@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/irq: Use access helper irq_data_get_affinity_mask()

This is a preparatory patch for moving irq_data struct members.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/irq: Hide 'HYP:' line in /proc/interrupts when not on Xen/Hyper-V

Hypervisor callback interrupts are only accounted on
Xen/Hyper-V. There is no point in having always-zero HYP: line
on other hypervisors or bare metal. Print the line only if
HYPERVISOR_CALLBACK_VECTOR was allocated.

Reported-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Andrew Jones <drjones@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1436286373-11908-1-git-send-email-vkuznets@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/irq: Retrieve irq data after locking irq_desc

irq_data is protected by irq_desc->lock, so retrieving the irq chip
from irq_data outside the lock is racy vs. an concurrent update. Move
it into the lock held region.

While at it add a comment why the vector walk does not require
vector_lock.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: xiao jin <jin.xiao@intel.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Yanmin Zhang <yanmin_zhang@linux.intel.com>
Link: http://lkml.kernel.org/r/20150705171102.331320612@linutronix.de

x86/irq: Use proper locking in check_irq_vectors_for_cpu_disable()

It's unsafe to examine fields in the irq descriptor w/o holding the
descriptor lock. Add proper locking.

While at it add a comment why the vector check can run lock less

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: xiao jin <jin.xiao@intel.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Yanmin Zhang <yanmin_zhang@linux.intel.com>
Link: http://lkml.kernel.org/r/20150705171102.236544164@linutronix.de

x86/irq, context_tracking: Document how IRQ context tracking works and add an RCU assertion

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/e8bdc4ed0193fb2fd130f3d6b7b8023e2ec1ab62.1435952415.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/irq: Show statistics information for posted-interrupts

Show the statistics information for notification event
and wakeup event for posted-interrupt in /proc/interrupts.

[ tglx: Named the short identifiers PIN and PIW to match the long
identifiers ]

Signed-off-by: Feng Wu <feng.wu@intel.com>
Cc: jiang.liu@linux.intel.com
Link: http://lkml.kernel.org/r/1432026437-16560-5-git-send-email-feng.wu@intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/irq: Define a global vector for VT-d Posted-Interrupts

Currently, we use a global vector as the Posted-Interrupts
Notification Event for all the vCPUs in the system. We need
to introduce another global vector for VT-d Posted-Interrtups,
which will be used to wakeup the sleep vCPU when an external
interrupt from a direct-assigned device happens for that vCPU.

[ tglx: Removed a gazillion of extra newlines ]

Signed-off-by: Feng Wu <feng.wu@intel.com>
Cc: jiang.liu@linux.intel.com
Link: http://lkml.kernel.org/r/1432026437-16560-4-git-send-email-feng.wu@intel.com
Suggested-by: Yang Zhang <yang.z.zhang@intel.com>
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86: Use entering[_ack]_irq() instead of open coding it

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/irq: Merge irq_regs & irq_stat

Move irq_regs and irq_stat definitions to irq.c.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1431185813-15413-2-git-send-email-brgerst@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/mce/amd: Introduce deferred error interrupt handler

Deferred errors indicate error conditions that were not corrected, but
require no action from S/W (or action is optional).These errors provide
info about a latent UC MCE that can occur when a poisoned data is
consumed by the processor.

Processors that report these errors can be configured to generate APIC
interrupts to notify OS about the error.

Provide an interrupt handler in this patch so that OS can catch these
errors as and when they happen. Currently, we simply log the errors and
exit the handler as S/W action is not mandated.

Signed-off-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: x86-ml <x86@kernel.org>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1430913538-1415-5-git-send-email-Aravind.Gopalakrishnan@amd.com
Signed-off-by: Borislav Petkov <bp@suse.de>

x86: fix up obsolete cpu function usage.

Thanks to spatch, plus manual removal of "&*".

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: x86@kernel.org

x86: Fix up obsolete __cpu_set() function usage

Thanks to spatch, plus manual removal of "&*".

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1425296150-4722-8-git-send-email-rusty@rustcorp.com.au
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/irq: Check for valid irq descriptor in check_irq_vectors_for_cpu_disable()

When an interrupt is migrated away from a cpu it will stay
in its vector_irq array until smp_irq_move_cleanup_interrupt
succeeded. The cfg->move_in_progress flag is cleared already
when the IPI was sent.

When the interrupt is destroyed after migration its 'struct
irq_desc' is freed and the vector_irq arrays are cleaned up.
But since cfg->move_in_progress is already 0 the references
at cpus before the last migration will not be cleared. So
this would leave a reference to an already destroyed irq
alive.

When the cpu is taken down at this point, the
check_irq_vectors_for_cpu_disable() function finds a valid irq
number in the vector_irq array, but gets NULL for its
descriptor and dereferences it, causing a kernel panic.

This has been observed on real systems at shutdown. Add a
check to check_irq_vectors_for_cpu_disable() for a valid
'struct irq_desc' to prevent this issue.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: alnovak@suse.com
Cc: joro@8bytes.org
Link: http://lkml.kernel.org/r/20150204132754.GA10078@suse.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86, irq: Properly tag virtualization entry in /proc/interrupts

The mis-naming likely was a copy-and-paste effect.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/54B9408B0200007800055E8B@mail.emea.novell.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86: Replace seq_printf() with seq_puts()

seq_puts is a lot cheaper than seq_printf, so use that to print
literal strings.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Link: http://lkml.kernel.org/r/1417208622-12264-1-git-send-email-linux@rasmusvillemoes.dk
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86: irq: Get correct available vectors for cpu disable

check_irq_vectors_for_cpu_disable() can overestimate the number of
available interrupt vectors, so the check for cpu down succeeds, but
the actual cpu removal fails.

It iterates from FIRST_EXTERNAL_VECTOR to NR_VECTORS, which is wrong
because the systems vectors are not taken into account.

Limit the search to first_system_vector instead of NR_VECTORS.

The second indicator for vector availability the used_vectors bitmap
is not taken into account at all. So system vectors,
e.g. IA32_SYSCALL_VECTOR (0x80) and IRQ_MOVE_CLEANUP_VECTOR (0x20),
are accounted as available.

Add a check for the used_vectors bitmap and do not account vectors
which are marked there.

[ tglx: Simplified code. Rewrote changelog and code comments. ]

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Prarit Bhargava <prarit@redhat.com>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Steven Rostedt (Red Hat) <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Elliott, Robert (Server Storage)" <Elliott@hp.com>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/1400160305-17774-2-git-send-email-prarit@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/irq: Fix fixup_irqs() error handling

Several patches to fix cpu hotplug and the down'd cpu's irq
relocations have been submitted in the past month or so. The
patches should resolve the problems with cpu hotplug and irq
relocation, however, there is always a possibility that a bug
still exists. The big problem with debugging these irq
reassignments is that the cpu down completes and then we get
random stack traces from drivers for which irqs have not been
properly assigned to a new cpu. The stack traces are a mix of
storage, network, and other kernel subsystem (I once saw the
serial port stop working ...) warnings and failures.

The problem with these failures is that they are difficult to
diagnose. There is no warning in the cpu hotplug down path to
indicate that an IRQ has failed to be assigned to a new cpu, and
all we are left with is a stack trace from a driver, or a
non-functional device. If we had some information on the
console debugging these situations would be much easier; after
all we can map an IRQ to a device by simply using lspci or
/proc/interrupts.

The current code, fixup_irqs(), which migrates IRQs from the
down'd cpu and is called close to the end of the cpu down path,
calls chip->set_irq_affinity which eventually calls
__assign_irq_vector(). Errors are not propogated back from this
function call and this results in silent irq relocation
failures.

This patch fixes this issue by returning the error codes up the
call stack and prints out a warning if there is a relocation
failure.

Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Rui Wang <rui.y.wang@intel.com>
Cc: Liu Ping Fan <kernelfans@gmail.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Cc: Lv Zheng <lv.zheng@intel.com>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: Yang Zhang <yang.z.zhang@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Steven Rostedt (Red Hat) <rostedt@goodmis.org>
Cc: Li Fei <fei.li@intel.com>
Cc: gong.chen@linux.intel.com
Link: http://lkml.kernel.org/r/1396440673-18286-1-git-send-email-prarit@redhat.com
[ Made small cleanliness tweaks. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/platform/hyperv: Handle VMBUS driver being a module

Hyper-V VMBUS driver can be a module; handle this case
correctly. Please apply.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Cc: olaf@aepfle.de
Cc: apw@canonical.com
Cc: jasowang@redhat.com
Link: http://lkml.kernel.org/r/1396421502-23222-1-git-send-email-kys@microsoft.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86: Add proper vector accounting for HYPERVISOR_CALLBACK_VECTOR

HyperV abuses a device interrupt to account for the
HYPERVISOR_CALLBACK_VECTOR.

Provide proper accounting as we have for the other vectors as well.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: x86 <x86@kernel.org>
Link: http://lkml.kernel.org/r/20140223212738.681855582@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86, cpu hotplug: Fix stack frame warning in check_irq_vectors_for_cpu_disable()

Further discussion here: http://marc.info/?l=linux-kernel&m=139073901101034&w=2

kbuild, 0day kernel build service, outputs the warning:

arch/x86/kernel/irq.c:333:1: warning: the frame size of 2056 bytes
is larger than 2048 bytes [-Wframe-larger-than=]

because check_irq_vectors_for_cpu_disable() allocates two cpumasks on the
stack. Fix this by moving the two cpumasks to a global file context.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Tested-by: David Rientjes <rientjes@google.com>
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Link: http://lkml.kernel.org/r/1390915331-27375-1-git-send-email-prarit@redhat.com
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: Yang Zhang <yang.z.zhang@Intel.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Janet Morgan <janet.morgan@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Ruiv Wang <ruiv.wang@gmail.com>
Cc: Gong Chen <gong.chen@linux.intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

x86: Add check for number of available vectors before CPU down

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=64791

When a cpu is downed on a system, the irqs on the cpu are assigned to
other cpus. It is possible, however, that when a cpu is downed there
aren't enough free vectors on the remaining cpus to account for the
vectors from the cpu that is being downed.

This results in an interesting "overflow" condition where irqs are
"assigned" to a CPU but are not handled.

For example, when downing cpus on a 1-64 logical processor system:

<snip>
[ 232.021745] smpboot: CPU 61 is now offline
[ 238.480275] smpboot: CPU 62 is now offline
[ 245.991080] ------------[ cut here ]------------
[ 245.996270] WARNING: CPU: 0 PID: 0 at net/sched/sch_generic.c:264 dev_watchdog+0x246/0x250()
[ 246.005688] NETDEV WATCHDOG: p786p1 (ixgbe): transmit queue 0 timed out
[ 246.013070] Modules linked in: lockd sunrpc iTCO_wdt iTCO_vendor_support sb_edac ixgbe microcode e1000e pcspkr joydev edac_core lpc_ich ioatdma ptp mdio mfd_core i2c_i801 dca pps_core i2c_core wmi acpi_cpufreq isci libsas scsi_transport_sas
[ 246.037633] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.12.0+ #14
[ 246.044451] Hardware name: Intel Corporation S4600LH ........../SVRBD-ROW_T, BIOS SE5C600.86B.01.08.0003.022620131521 02/26/2013
[ 246.057371] 0000000000000009 ffff88081fa03d40 ffffffff8164fbf6 ffff88081fa0ee48
[ 246.065728] ffff88081fa03d90 ffff88081fa03d80 ffffffff81054ecc ffff88081fa13040
[ 246.074073] 0000000000000000 ffff88200cce0000 0000000000000040 0000000000000000
[ 246.082430] Call Trace:
[ 246.085174] <IRQ> [<ffffffff8164fbf6>] dump_stack+0x46/0x58
[ 246.091633] [<ffffffff81054ecc>] warn_slowpath_common+0x8c/0xc0
[ 246.098352] [<ffffffff81054fb6>] warn_slowpath_fmt+0x46/0x50
[ 246.104786] [<ffffffff815710d6>] dev_watchdog+0x246/0x250
[ 246.110923] [<ffffffff81570e90>] ? dev_deactivate_queue.constprop.31+0x80/0x80
[ 246.119097] [<ffffffff8106092a>] call_timer_fn+0x3a/0x110
[ 246.125224] [<ffffffff8106280f>] ? update_process_times+0x6f/0x80
[ 246.132137] [<ffffffff81570e90>] ? dev_deactivate_queue.constprop.31+0x80/0x80
[ 246.140308] [<ffffffff81061db0>] run_timer_softirq+0x1f0/0x2a0
[ 246.146933] [<ffffffff81059a80>] __do_softirq+0xe0/0x220
[ 246.152976] [<ffffffff8165fedc>] call_softirq+0x1c/0x30
[ 246.158920] [<ffffffff810045f5>] do_softirq+0x55/0x90
[ 246.164670] [<ffffffff81059d35>] irq_exit+0xa5/0xb0
[ 246.170227] [<ffffffff8166062a>] smp_apic_timer_interrupt+0x4a/0x60
[ 246.177324] [<ffffffff8165f40a>] apic_timer_interrupt+0x6a/0x70
[ 246.184041] <EOI> [<ffffffff81505a1b>] ? cpuidle_enter_state+0x5b/0xe0
[ 246.191559] [<ffffffff81505a17>] ? cpuidle_enter_state+0x57/0xe0
[ 246.198374] [<ffffffff81505b5d>] cpuidle_idle_call+0xbd/0x200
[ 246.204900] [<ffffffff8100b7ae>] arch_cpu_idle+0xe/0x30
[ 246.210846] [<ffffffff810a47b0>] cpu_startup_entry+0xd0/0x250
[ 246.217371] [<ffffffff81646b47>] rest_init+0x77/0x80
[ 246.223028] [<ffffffff81d09e8e>] start_kernel+0x3ee/0x3fb
[ 246.229165] [<ffffffff81d0989f>] ? repair_env_string+0x5e/0x5e
[ 246.235787] [<ffffffff81d095a5>] x86_64_start_reservations+0x2a/0x2c
[ 246.242990] [<ffffffff81d0969f>] x86_64_start_kernel+0xf8/0xfc
[ 246.249610] ---[ end trace fb74fdef54d79039 ]---
[ 246.254807] ixgbe 0000:c2:00.0 p786p1: initiating reset due to tx timeout
[ 246.262489] ixgbe 0000:c2:00.0 p786p1: Reset adapter
Last login: Mon Nov 11 08:35:14 from 10.18.17.119
[root@(none) ~]# [ 246.792676] ixgbe 0000:c2:00.0 p786p1: detected SFP+: 5
[ 249.231598] ixgbe 0000:c2:00.0 p786p1: NIC Link is Up 10 Gbps, Flow Control: RX/TX
[ 246.792676] ixgbe 0000:c2:00.0 p786p1: detected SFP+: 5
[ 249.231598] ixgbe 0000:c2:00.0 p786p1: NIC Link is Up 10 Gbps, Flow Control: RX/TX

(last lines keep repeating. ixgbe driver is dead until module reload.)

If the downed cpu has more vectors than are free on the remaining cpus on the
system, it is possible that some vectors are "orphaned" even though they are
assigned to a cpu. In this case, since the ixgbe driver had a watchdog, the
watchdog fired and notified that something was wrong.

This patch adds a function, check_vectors(), to compare the number of vectors
on the CPU going down and compares it to the number of vectors available on
the system. If there aren't enough vectors for the CPU to go down, an
error is returned and propogated back to userspace.

v2: Do not need to look at percpu irqs
v3: Need to check affinity to prevent counting of MSIs in IOAPIC Lowest
Priority Mode
v4: Additional changes suggested by Gong Chen.
v5/v6/v7/v8: Updated comment text

Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Link: http://lkml.kernel.org/r/1389613861-3853-1-git-send-email-prarit@redhat.com
Reviewed-by: Gong Chen <gong.chen@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: Yang Zhang <yang.z.zhang@Intel.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Janet Morgan <janet.morgan@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Ruiv Wang <ruiv.wang@gmail.com>
Cc: Gong Chen <gong.chen@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: <stable@vger.kernel.org>

x86/irq: Fix do_IRQ() interrupt warning for cpu hotplug retriggered irqs

During heavy CPU-hotplug operations the following spurious kernel warnings
can trigger:

do_IRQ: No ... irq handler for vector (irq -1)

[ See: https://bugzilla.kernel.org/show_bug.cgi?id=64831 ]

When downing a cpu it is possible that there are unhandled irqs
left in the APIC IRR register. The following code path shows
how the problem can occur:

1. CPU 5 is to go down.

2. cpu_disable() on CPU 5 executes with interrupt flag cleared
by local_irq_save() via stop_machine().

3. IRQ 12 asserts on CPU 5, setting IRR but not ISR because
interrupt flag is cleared (CPU unabled to handle the irq)

4. IRQs are migrated off of CPU 5, and the vectors' irqs are set
to -1. 5. stop_machine() finishes cpu_disable()

6. cpu_die() for CPU 5 executes in normal context.

7. CPU 5 attempts to handle IRQ 12 because the IRR is set for
IRQ 12. The code attempts to find the vector's IRQ and cannot
because it has been set to -1. 8. do_IRQ() warning displays
warning about CPU 5 IRQ 12.

I added a debug printk to output which CPU & vector was
retriggered and discovered that that we are getting bogus
events. I see a 100% correlation between this debug printk in
fixup_irqs() and the do_IRQ() warning.

This patchset resolves this by adding definitions for
VECTOR_UNDEFINED(-1) and VECTOR_RETRIGGERED(-2) and modifying
the code to use them.

Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=64831
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Reviewed-by: Rui Wang <rui.y.wang@intel.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: Yang Zhang <yang.z.zhang@Intel.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: janet.morgan@Intel.com
Cc: tony.luck@Intel.com
Cc: ruiv.wang@gmail.com
Link: http://lkml.kernel.org/r/1388938252-16627-1-git-send-email-prarit@redhat.com
[ Cleaned up the code a bit. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86, asmlinkage: Make all interrupt handlers asmlinkage / __visible

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: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1375740170-7446-4-git-send-email-andi@firstfloor.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

trace,x86: Move creation of irq tracepoints from apic.c to irq.c

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: Steven Rostedt <rostedt@goodmis.org>

x86, trace: Add irq vector tracepoints

[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: Seiji Aguchi <seiji.aguchi@hds.com>
Link: http://lkml.kernel.org/r/51C323ED.5050708@hds.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>

x86, trace: Introduce entering/exiting_irq()

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: Seiji Aguchi <seiji.aguchi@hds.com>
Link: http://lkml.kernel.org/r/51C3238D.9040706@hds.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>

x86: Eliminate irq_mis_count counted in arch_irq_stat

With the current implementation, kstat_cpu(cpu).irqs_sum is also
increased in case of irq_mis_count increment.

So there is no need to count irq_mis_count in arch_irq_stat,
otherwise irq_mis_count will be counted twice in the sum of
/proc/stat.

Reported-by: Liu Chuansheng <chuansheng.liu@intel.com>
Signed-off-by: Li Fei <fei.li@intel.com>
Acked-by: Liu Chuansheng <chuansheng.liu@intel.com>
Cc: tomoki.sekiyama.qu@hitachi.com
Cc: joe@perches.com
Link: http://lkml.kernel.org/r/1366980611.32469.7.camel@fli24-HP-Compaq-8100-Elite-CMT-PC
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

KVM: VMX: Register a new IPI for posted interrupt

Posted Interrupt feature requires a special IPI to deliver posted interrupt
to guest. And it should has a high priority so the interrupt will not be
blocked by others.
Normally, the posted interrupt will be consumed by vcpu if target vcpu is
running and transparent to OS. But in some cases, the interrupt will arrive
when target vcpu is scheduled out. And host will see it. So we need to
register a dump handler to handle it.

Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

x86: Distinguish TLB shootdown interrupts from other functions call interrupts

As TLB shootdown requests to other CPU cores are now using function call
interrupts, TLB shootdowns entry in /proc/interrupts is always shown as 0.

This behavior change was introduced by commit 52aec3308db8 ("x86/tlb:
replace INVALIDATE_TLB_VECTOR by CALL_FUNCTION_VECTOR").

This patch reverts TLB shootdowns entry in /proc/interrupts to count TLB
shootdowns separately from the other function call interrupts.

Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com>
Link: http://lkml.kernel.org/r/20120926021128.22212.20440.stgit@hpxw
Acked-by: Alex Shi <alex.shi@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

x86/fixup_irq: Use cpu_online_mask instead of cpu_all_mask

When one CPU is going down and this CPU is the last one in irq
affinity, current code is setting cpu_all_mask as the new
affinity for that irq.

But for some systems (such as in Medfield Android mobile) the
firmware sends the interrupt to each CPU in the irq affinity
mask, averaged, and cpu_all_mask includes all potential CPUs,
i.e. offline ones as well.

So replace cpu_all_mask with cpu_online_mask.

Signed-off-by: liu chuansheng <chuansheng.liu@intel.com>
Acked-by: Yanmin Zhang <yanmin_zhang@linux.intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/27240C0AC20F114CBF8149A2696CBE4A137286@SHSMSX101.ccr.corp.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/ioapic: Fix NULL pointer dereference on CPU hotplug after disabling irqs

In the current kernel, percpu variable `vector_irq' is not always
cleared when a CPU is offlined. If the CPU that has the disabled
irqs in vector_irq is hotplugged again, __setup_vector_irq()
hits invalid irq vector and may crash.

This bug can be reproduced as following;

# echo 0 > /sys/devices/system/cpu/cpu7/online
# modprobe -r some_driver_using_interrupts # vector_irq@cpu7 uncleared
# echo 1 > /sys/devices/system/cpu/cpu7/online # kernel may crash

To fix this problem, this patch clears vector_irq in
__fixup_irqs() when the CPU is offlined.

This also reverts commit f6175f5bfb4c, which partially fixes
this bug by clearing vector in __clear_irq_vector(). But in
environments with IOMMU IRQ remapper, it could fail because
cfg->domain doesn't contain offlined CPUs. With this patch, the
fix in __clear_irq_vector() can be reverted because every
vector_irq is already cleared in __fixup_irqs() on offlined CPUs.

Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: yrl.pp-manager.tt@hitachi.com
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Alexander Gordeev <agordeev@redhat.com>
Link: http://lkml.kernel.org/r/20120726104732.2889.19144.stgit@kvmdev
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/debug: Add KERN_<LEVEL> to bare printks, convert printks to pr_<level>

Use a more current logging style:

- Bare printks should have a KERN_<LEVEL> for consistency's sake
- Add pr_fmt where appropriate
- Neaten some macro definitions
- Convert some Ok output to OK
- Use "%s: ", __func__ in pr_fmt for summit
- Convert some printks to pr_<level>

Message output is not identical in all cases.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: levinsasha928@gmail.com
Link: http://lkml.kernel.org/r/1337655007.24226.10.camel@joe2Laptop
[ merged two similar patches, tidied up the changelog ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86: Preserve lazy irq disable semantics in fixup_irqs()

The default irq_disable() sematics are to mark the interrupt disabled,
but keep it unmasked. If the interrupt is delivered while marked
disabled, the low level interrupt handler masks it and marks it
pending. This is important for detecting wakeup interrupts during
suspend and for edge type interrupts to avoid losing interrupts.

fixup_irqs() moves the interrupts away from an offlined cpu. For
certain interrupt types it needs to mask the interrupt line before
changing the affinity. After affinity has changed the interrupt line
is unmasked again, but only if it is not marked disabled.

This breaks the lazy irq disable semantics and causes problems in
suspend as the interrupt can be lost or wakeup functionality is
broken.

Check irqd_irq_masked() instead of irqd_irq_disabled() because
irqd_irq_masked() is only set, when the core code actually masked the
interrupt line. If it's not set, we unmask the interrupt and let the
lazy irq disable logic deal with an eventually incoming interrupt.

[ tglx: Massaged changelog and added a comment ]

Signed-off-by: liu chuansheng <chuansheng.liu@intel.com>
Cc: Yanmin Zhang <yanmin_zhang@linux.intel.com>
Link: http://lkml.kernel.org/r/27240C0AC20F114CBF8149A2696CBE4A05DFB3@SHSMSX101.ccr.corp.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86: Convert per-cpu counter icr_read_retry_count into a member of irq_stat

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: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Cc: Jörn Engel <joern@logfs.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: Add per-cpu stat counter for APIC ICR read tries

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: Fernando 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: Ingo Molnar <mingo@elte.hu>

x86: Call idle notifier after irq_enter()

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: Frederic 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: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

x86: Fix files explicitly requiring export.h for EXPORT_SYMBOL/THIS_MODULE

These files were implicitly getting EXPORT_SYMBOL via device.h
which was including module.h, but that will be fixed up shortly.

By fixing these now, we can avoid seeing things like:

arch/x86/kernel/rtc.c:29: warning: type defaults to ‘int’ in declaration of ‘EXPORT_SYMBOL’
arch/x86/kernel/pci-dma.c:20: warning: type defaults to ‘int’ in declaration of ‘EXPORT_SYMBOL’
arch/x86/kernel/e820.c:69: warning: type defaults to ‘int’ in declaration of ‘EXPORT_SYMBOL_GPL’

[ with input from Randy Dunlap <rdunlap@xenotime.net> and also
from Stephen Rothwell <sfr@canb.auug.org.au> ]

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

x86: Don't unmask disabled irqs when migrating them

It doesn't make sense to unconditionally unmask a disabled irq when
migrating it from offlined cpu to another. If the irq triggers then it
will be disabled in the interrupt handler anyway. So we can just avoid
unmasking it.

[ tglx: Made masking unconditional again and fixed the changelog ]

Signed-off-by: Fengzhe Zhang <fengzhe.zhang@intel.com>
Signed-off-by: Kevin Tian <kevin.tian@intel.com>
Cc: Ian Campbell <Ian.Campbell@citrix.com>
Cc: Jan Beulich <JBeulich@novell.com>
Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
Link: http://lkml.kernel.org/r/%3C625BA99ED14B2D499DC4E29D8138F1505C8ED7F7E3%40shsmsx502.ccr.corp.intel.com%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86: Skip migrating IRQF_PER_CPU irqs in fixup_irqs()

IRQF_PER_CPU means that the irq cannot be moved away from a given
cpu. So it must not be migrated when the cpu goes offline.

[ tglx: massaged changelog ]

Signed-off-by: Fengzhe Zhang <fengzhe.zhang@intel.com>
Signed-off-by: Kevin Tian <kevin.tian@intel.com>
Cc: Ian Campbell <Ian.Campbell@citrix.com>
Cc: Jan Beulich <JBeulich@novell.com>
Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
Link: http://lkml.kernel.org/r/%3C625BA99ED14B2D499DC4E29D8138F1505C8ED7F7E2%40shsmsx502.ccr.corp.intel.com%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86: Stop including <linux/delay.h> in two asm header files

Stop including <linux/delay.h> in x86 header files which don't
need it. This will let the compiler complain when this header is
not included by source files when it should, so that
contributors can fix the problem before building on other
architectures starts to fail.

Credits go to Geert for the idea.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: James E.J. Bottomley <James.Bottomley@suse.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
LKML-Reference: <20110325152014.297890ec@endymion.delvare>
[ this also fixes an upstream build bug in drivers/media/rc/ite-cir.c ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: Use generic show_interrupts

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86: Use the proper accessors in fixup_irqs()

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86: Add device tree support

This patch adds minimal support for device tree on x86. The device
tree blob is passed to the kernel via setup_data which requires at
least boot protocol 2.09.

Memory size, restricted memory regions, boot arguments are gathered
the traditional way so things like cmd_line are just here to let the
code compile.

The current plan is use the device tree as an extension and to gather
information which can not be enumerated and would have to be hardcoded
otherwise. This includes things like
- which devices are on this I2C/SPI bus?
- how are the interrupts wired to IO APIC?
- where could my hpet be?

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Dirk Brandewie <dirk.brandewie@gmail.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Cc: sodaville@linutronix.de
Cc: devicetree-discuss@lists.ozlabs.org
LKML-Reference: <1298405266-1624-3-git-send-email-bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86: Eliminate pointless adjustment attempts in fixup_irqs()

Not only when an IRQ's affinity equals cpu_online_mask is there
no need to actually try to adjust the affinity, but also when
it's a subset thereof. This particularly avoids adjustment
attempts during system shutdown to any IRQs bound to CPU#0.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Gary Hade <garyhade@us.ibm.com>
LKML-Reference: <4D5D52C2020000780003272C@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: Readd missing irq_to_desc() in fixup_irq()

commit a3c08e5d(x86: Convert irq_chip access to new functions)
accidentally zapped desc = irq_to_desc(irq); in the vector loop.
So we lock some random irq descriptor.

Add it back.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@kernel.org> # .37

x86: Use this_cpu_ops to optimize code

Go through x86 code and replace __get_cpu_var and get_cpu_var
instances that refer to a scalar and are not used for address
determinations.

Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

x86, of: Define irq functions to allow drivers/of/* to build on x86

- Define a stub irq_create_of_mapping for x86 as a stop-gap solution until
drivers/of/irq is further along.
- Define irq_dispose_mapping for x86 to appease of_i2c.c

These are needed to allow stuff in drivers/of/ to build on x86. This stuff
will eventually get replaced; quoting Grant,

"The long term plan is to have the drivers/of/ code handling the mapping
intelligently like powerpc currently does." But for now, just provide
these functions.

Signed-off-by: Andres Salomon <dilinger@queued.net>
LKML-Reference: <20101111214526.5de7121b@queued.net>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

irq_work: Add generic hardirq context callbacks

Provide a mechanism that allows running code in IRQ context. It is
most useful for NMI code that needs to interact with the rest of the
system -- like wakeup a task to drain buffers.

Perf currently has such a mechanism, so extract that and provide it as
a generic feature, independent of perf so that others may also
benefit.

The IRQ context callback is generated through self-IPIs where
possible, or on architectures like powerpc the decrementer (the
built-in timer facility) is set to generate an interrupt immediately.

Architectures that don't have anything like this get to do with a
callback from the timer tick. These architectures can call
irq_work_run() at the tail of any IRQ handlers that might enqueue such
work (like the perf IRQ handler) to avoid undue latencies in
processing the work.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Kyle McMartin <kyle@mcmartin.ca>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
[ various fixes ]
Signed-off-by: Huang Ying <ying.huang@intel.com>
LKML-Reference: <1287036094.7768.291.camel@yhuang-dev>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: Convert irq_chip access to new functions

Before moving the irq chips to the new functions, fixup direct callers.

The cpu offline irq fixup code needs to become generic and archs need
to honour the "force" flag as an indicator, but that's for later.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@elte.hu>

genirq: Convert irq_desc.lock to raw_spinlock

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>

x86: Tighten conditionals on MCE related statistics

irq_thermal_count is only being maintained when
X86_THERMAL_VECTOR, and both X86_THERMAL_VECTOR and
X86_MCE_THRESHOLD don't need extra wrapping in X86_MCE
conditionals.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Yong Wang <yong.y.wang@intel.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Borislav Petkov <borislav.petkov@amd.com>
Cc: Arjan van de Ven <arjan@infradead.org>
LKML-Reference: <4B06AFA902000078000211F8@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: Remove local_irq_enable()/local_irq_disable() in fixup_irqs()

To ensure that we handle all the pending interrupts (destined
for this cpu that is going down) in the interrupt subsystem
before the cpu goes offline, fixup_irqs() does:

local_irq_enable();
mdelay(1);
local_irq_disable();

Enabling interrupts is not a good thing as this cpu is already
offline. So this patch replaces that logic with,

mdelay(1);
check APIC_IRR bits
Retrigger the irq at the new destination if any interrupt has arrived
via IPI.

For IO-APIC level triggered interrupts, this retrigger IPI will
appear as an edge interrupt. ack_apic_level() will detect this
condition and IO-APIC RTE's remoteIRR is cleared using directed
EOI(using IO-APIC EOI register) on Intel platforms and for
others it uses the existing mask+edge logic followed by
unmask+level.

We can also remove mdelay() and then send spuriuous interrupts
to new cpu targets for all the irqs that were handled previously
by this cpu that is going offline. While it works, I have seen
spurious interrupt messages (nothing wrong but still annoying
messages during cpu offline, which can be seen during
suspend/resume etc)

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Acked-by: Gary Hade <garyhade@us.ibm.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
LKML-Reference: <20091026230002.043281924@sbs-t61.sc.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: Force irq complete move during cpu offline

When a cpu goes offline, fixup_irqs() try to move irq's
currently destined to the offline cpu to a new cpu. But this
attempt will fail if the irq is recently moved to this cpu and
the irq still hasn't arrived at this cpu (for non intr-remapping
platforms this is when we free the vector allocation at the
previous destination) that is about to go offline.

This will endup with the interrupt subsystem still pointing the
irq to the offline cpu, causing that irq to not work any more.

Fix this by forcing the irq to complete its move (its been a
long time we moved the irq to this cpu which we are offlining
now) and then move this irq to a new cpu before this cpu goes
offline.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Acked-by: Gary Hade <garyhade@us.ibm.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
LKML-Reference: <20091026230001.848830905@sbs-t61.sc.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86, intr-remap: Avoid irq_chip mask/unmask in fixup_irqs() for intr-remapping

In the presence of interrupt-remapping, irqs will be migrated in
the process context and we don't do (and there is no need to)
irq_chip mask/unmask while migrating the interrupt.

Similarly fix the fixup_irqs() that get called during cpu
offline and avoid calling irq_chip mask/unmask for irqs that are
ok to be migrated in the process context.

While we didn't observe any race condition with the existing
code, this change takes complete advantage of
interrupt-remapping in the newer generation platforms and avoids
any potential HW lockup's (that often worry Eric :)

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: garyhade@us.ibm.com
LKML-Reference: <20091026230001.661423939@sbs-t61.sc.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: Unify fixup_irqs() for 32-bit and 64-bit kernels

There is no reason to have different fixup_irqs() for 32-bit and
64-bit kernels. Unify by using the superior 64-bit version for
both the kernels.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Gary Hade <garyhade@us.ibm.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
LKML-Reference: <20091026230001.562512739@sbs-t61.sc.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: UV RTC: Rename generic_interrupt to x86_platform_ipi

Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
LKML-Reference: <20091014142257.GE11048@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86, perf_event: Rename 'performance counter interrupt'

In 'cdd6c482c9ff9c55475ee7392ec8f672eddb7be6', we renamed
Performance Counters -> Performance Events.

The name showed up in /proc/interrupts also needs a change. I use
PMI (Performance monitoring interrupt) here, since it is the
official name used in Intel's documents.

Signed-off-by: Li Hong <lihong.hi@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091014105039.GA22670@uhli>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Revert "x86, timers: Check for pending timers after (device) interrupts"

This reverts commit 9bcbdd9c58617f1301dd4f17c738bb9bc73aca70.

The real bug producing LatencyTop latencies has been fixed in:

f5dc375: sched: Update the clock of runqueue select_task_rq() selected

And the commit being reverted here triggers local timer processing
from every device IRQ. If device IRQs come in at a high frequency,
this could cause a performance regression.

The commit being reverted here purely 'fixed' the reported latency
as a side effect, because CPUs were being moved out of idle more
often.

Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Frans Pop <elendil@planet.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <20091008064041.67219b13@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86, timers: Check for pending timers after (device) interrupts

Now that range timers and deferred timers are common, I found a
problem with these using the "perf timechart" tool. Frans Pop also
reported high scheduler latencies via LatencyTop, when using
iwlagn.

It turns out that on x86, these two 'opportunistic' timers only get
checked when another "real" timer happens. These opportunistic
timers have the objective to save power by hitchhiking on other
wakeups, as to avoid CPU wakeups by themselves as much as possible.

The change in this patch runs this check not only at timer
interrupts, but at all (device) interrupts. The effect is that:

1) the deferred timers/range timers get delayed less

2) the range timers cause less wakeups by themselves because
the percentage of hitchhiking on existing wakeup events goes up.

I've verified the working of the patch using "perf timechart", the
original exposed bug is gone with this patch. Frans also reported
success - the latencies are now down in the expected ~10 msec
range.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Tested-by: Frans Pop <elendil@planet.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <20091008064041.67219b13@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: mce: Rename CONFIG_X86_NEW_MCE to CONFIG_X86_MCE

Drop the CONFIG_X86_NEW_MCE symbol and change all
references to it to check for CONFIG_X86_MCE directly.

No code changes

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

x86, mce: fix for mce counters

Make the MCE counters work on 32bit and add poll count in
arch_irq_stat_cpu.

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

x86, mce: add MCE poll count to /proc/interrupts

Keep a count of the machine check polls (or CMCI events) in
/proc/interrupts.

Andi needs this for debugging, but it's also useful in general
to see what's going in by the kernel.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

x86, mce: add machine check exception count in /proc/interrupts

Useful for debugging, but it's also good general policy
to have a counter for all special interrupts there. This makes it easier
to diagnose where a CPU is spending its time.

[ Impact: feature, debugging tool ]

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

x86, mce: use 64bit machine check code on 32bit

The 64bit machine check code is in many ways much better than
the 32bit machine check code: it is more specification compliant,
is cleaner, only has a single code base versus one per CPU,
has better infrastructure for recovery, has a cleaner way to communicate
with user space etc. etc.

Use the 64bit code for 32bit too.

This is the second attempt to do this. There was one a couple of years
ago to unify this code for 32bit and 64bit. Back then this ran into some
trouble with K7s and was reverted.

I believe this time the K7 problems (and some others) are addressed.
I went over the old handlers and was very careful to retain
all quirks.

But of course this needs a lot of testing on old systems. On newer
64bit capable systems I don't expect much problems because they have been
already tested with the 64bit kernel.

I made this a CONFIG for now that still allows to select the old
machine check code. This is mostly to make testing easier,
if someone runs into a problem we can ask them to try
with the CONFIG switched.

The new code is default y for more coverage.

Once there is confidence the 64bit code works well on older hardware
too the CONFIG_X86_OLD_MCE and the associated code can be easily
removed.

This causes a behaviour change for 32bit installations. They now
have to install the mcelog package to be able to log
corrected machine checks.

The 64bit machine check code only handles CPUs which support the
standard Intel machine check architecture described in the IA32 SDM.
The 32bit code has special support for some older CPUs which
have non standard machine check architectures, in particular
WinChip C3 and Intel P5. I made those a separate CONFIG option
and kept them for now. The WinChip variant could be probably
removed without too much pain, it doesn't really do anything
interesting. P5 is also disabled by default (like it
was before) because many motherboards have it miswired, but
according to Alan Cox a few embedded setups use that one.

Forward ported/heavily changed version of old patch, original patch
included review/fixes from Thomas Gleixner, Bert Wesarg.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

perf_counter: fix alignment in /proc/interrupts

Trivial fix on columns alignment in /proc/interrupts file.

Signed-off-by: Luis Henriques <henrix@sapo.pt>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20090413192449.GA3920@hades.domain.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: apic - introduce dummy apic operations

Impact: refactor, speed up and robustize code

In case if apic was disabled by kernel option
or by hardware limits we can use dummy operations
in apic->write to simplify the ack_APIC_irq() code.

At the lame time the patch fixes the missed EOI in
do_IRQ function (which has place if kernel is compiled
as X86-32 and interrupt without handler happens where
apic was not asked to be disabled via kernel option).

Note that native_apic_write_dummy() consists of
WARN_ON_ONCE to catch any buggy writes on enabled
APICs. Could be removed after some time of testing.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
LKML-Reference: <20090412165058.724788431@openvz.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: irq.c - tiny cleanup

Impact: cleanup, robustization

1) guard ack_bad_irq with printk_ratelimit since there is no
guarantee we will not be flooded one day

2) use pr_emerg() helper

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
LKML-Reference: <20090412165058.277579847@openvz.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: clean up declarations and variables

Impact: cleanup, no code changed

- syscalls.h update declarations due to unifications
- irq.c declare smp_generic_interrupt() before it gets used
- process.c declare sys_fork() and sys_vfork() before they get used
- tsc.c rename tsc_khz shadowed variable
- apic/probe_32.c declare apic_default before it gets used
- apic/nmi.c prev_nmi_count should be unsigned
- apic/io_apic.c declare smp_irq_move_cleanup_interrupt() before it gets used
- mm/init.c declare direct_gbpages and free_initrd_mem before they get used

Signed-off-by: Jaswinder Singh Rajput <jaswinder@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: smarten /proc/interrupts output for new counters

Now /proc/interrupts of tip tree has new counters:

PLT: Platform interrupts

Format change of output, as like that by commit:

commit 7a81d9a7da03d2f27840d659f97ef140d032f609
x86: smarten /proc/interrupts output

should be applied to these new counters too.

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Jan Beulich <jbeulich@novell.com>
LKML-Reference: <49C98DEA.8060208@jp.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: smarten /proc/interrupts output for new counters

Now /proc/interrupts of tip tree has new counters:

CNT: Performance counter interrupts

Format change of output, as like that by commit:

commit 7a81d9a7da03d2f27840d659f97ef140d032f609
x86: smarten /proc/interrupts output

should be applied to these new counters too.

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Jan Beulich <jbeulich@novell.com>
LKML-Reference: <49C98DEA.8060208@jp.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

perf_counter: x86: self-IPI for pending work

Implement set_perf_counter_pending() with a self-IPI so that it will
run ASAP in a usable context.

For now use a second IRQ vector, because the primary vector pokes
the apic in funny ways that seem to confuse things.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
LKML-Reference: <20090406094517.724626696@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: irq.c keep CONFIG_X86_LOCAL_APIC interrupts together

Impact: cleanup

keep CONFIG_X86_LOCAL_APIC interrupts together to avoid extra ifdef

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>

x86: irq.c use same path for show_interrupts

Impact: cleanup

SMP and !SMP will use same path for show_interrupts

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>

x86: smarten /proc/interrupts output

Impact: change /proc/interrupts output ABI

With the number of interrupts on large systems growing, assumptions on
the width an interrupt number requires when converted to a decimal
string turn invalid. Therefore, calculate the maximum number of digits
dynamically.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
LKML-Reference: <49B911EB.76E4.0078.0@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: UV, SGI RTC: add generic system vector

This patch allocates a system interrupt vector for various platform
specific uses.

Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: john stultz <johnstul@us.ibm.com>
LKML-Reference: <20090304185605.GA24419@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86, apic: remove genapic.h

Impact: cleanup

Remove genapic.h and remove all references to it.

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

x86: fold apic_ops into genapic

Impact: cleanup

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

v2: fix the sgi_uv build

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: unify do_IRQ()

With the differences in interrupt handling hoisted into handle_irq(),
do_IRQ is more or less identical between 32 and 64 bit, so unify it.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86-64: Move irq stats from PDA to per-cpu and consolidate with 32-bit.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

x86: irq.c fix style problems

Impact: cleanup

Fix:

WARNING: Use #include <linux/smp.h> instead of <asm/smp.h>

total: 0 errors, 1 warnings

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: export vector_used_by_percpu_irq

Impact: build fix

lguest can be built as a module and makes use of this new symbol:

ERROR: "vector_used_by_percpu_irq" [drivers/lguest/lg.ko] undefined!

export it.

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

performance counters: x86 support

Implement performance counters for x86 Intel CPUs.

It's simplified right now: the PERFMON CPU feature is assumed,
which is available in Core2 and later Intel CPUs.

The design is flexible to be extended to more CPU types as well.

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

sparse irq_desc[] array: core kernel and x86 changes

Impact: new feature

Problem on distro kernels: irq_desc[NR_IRQS] takes megabytes of RAM with
NR_CPUS set to large values. The goal is to be able to scale up to much
larger NR_IRQS value without impacting the (important) common case.

To solve this, we generalize irq_desc[NR_IRQS] to an (optional) array of
irq_desc pointers.

When CONFIG_SPARSE_IRQ=y is used, we use kzalloc_node to get irq_desc,
this also makes the IRQ descriptors NUMA-local (to the site that calls
request_irq()).

This gets rid of the irq_cfg[] static array on x86 as well: irq_cfg now
uses desc->chip_data for x86 to store irq_cfg.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

genirq: fix off by one and coding style

Fix off-by-one in for_each_irq_desc_reverse().

Impact is near zero in practice, because nothing substantial wants to
iterate down to IRQ#0 - but fix it nevertheless.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86: move ack_bad_irq() to irq.c

Share more duplicated code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86: unify show_interrupts() and proc helpers

show_interrupts() and proc helpers are basically the same for
32 and 64 bit. Move them to a shared source file.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>