smpboot is very creative with the ways to disable ioapic.

smpboot_clear_io_apic() smpboot_clear_io_apic_irqs() and
disable_ioapic_support() serve a similar purpose.

smpboot_clear_io_apic_irqs() is the most useless of all
functions as it clears a variable which has not been setup yet.

Aside of that it has the same ifdef mess and conditionals around the
ioapic related code, which can now be removed.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NBorislav Petkov <bp@alien8.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20150115211703.650280684@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

We have proper stubs for the IOAPIC=n case and the setup/enable
function have the required checks inside now. Remove the ifdeffery and
the copy&pasted conditionals.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>C
Acked-by: NBorislav Petkov <bp@alien8.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20150115211703.569830549@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

No point to have the same checks at every call site. Add them to the
functions, so they can be called unconditionally.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NBorislav Petkov <bp@alien8.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20150115211703.490719938@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

To avoid lots of ifdeffery provide proper stubs for setup_IO_APIC(),
enable_IO_APIC() and setup_ioapic_dest().
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NBorislav Petkov <bp@alien8.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20150115211703.397170414@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

No point for a separate header file.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20150115211703.304126687@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Use the state information to simplify the disable logic further.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NBorislav Petkov <bp@alien8.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20150115211703.209387598@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

enable_x2apic() is a convoluted unreadable mess because it is used for
both enablement in early boot and for setup in cpu_init().

Split the code into x2apic_enable() for enablement and x2apic_setup()
for setup of (secondary cpus). Make use of the new state tracking to
simplify the logic.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20150115211703.129287153@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

There is no point in postponing the hardware disablement of x2apic. It
can be disabled right away in the nox2apic setup function.

Disable it right away and set the state to DISABLED . This allows to
remove all the nox2apic conditionals all over the place.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20150115211703.051214090@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Having 3 different variables to track the state is just silly and
error prone. Add a proper state tracking variable which covers the
three possible states: ON/OFF/DISABLED.

We cannot use x2apic_mode for this as this would require to change all
users of x2apic_mode with explicit comparisons for a state value
instead of treating it as boolean.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NBorislav Petkov <bp@alien8.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20150115211702.955392443@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Rename the argument of try_to_enable_x2apic() so the purpose becomes
more clear.

Make the pr_warning more consistent and avoid the double print of
"disabling".
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NBorislav Petkov <bp@alien8.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20150115211702.876012628@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

No point in having try_to_enable_x2apic() outside of the
CONFIG_X86_X2APIC section and having inline functions and more ifdefs
to deal with it. Move the code into the existing ifdef section and
remove the inline cruft.

Fixup the printk about not enabling interrupt remapping as suggested
by Boris.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20150115211702.795388613@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

No point in delaying the x2apic detection for the CONFIG_X86_X2APIC=n
case to enable_IR_x2apic(). We rather detect that before we try to
setup anything there.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20150115211702.702479404@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

If x2apic_preenabled is not enabled, then disable_x2apic() is not
called from various places which results in x2apic_disabled not being
set. So other code pathes can happily reenable the x2apic.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20150115211702.621431109@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

The x2apic_preenabled flag is just a horrible hack and if X2APIC
support is disabled it does not reflect the actual hardware
state. Check the hardware instead.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20150115211702.541280622@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Having several disjunct pieces of code for x2apic support makes
reading the code unnecessarily hard. Move it to one ifdeffed section.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NBorislav Petkov <bp@alien8.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20150115211702.445212133@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

No point in having a static variable around which is always 0. Let the
compiler optimize code out if disabled.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NBorislav Petkov <bp@alien8.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20150115211702.363274310@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

enable_IR_x2apic() grew a open coded x2apic detection. Implement a
proper helper function which shares the code with the already existing
x2apic_enabled().

Made it use rdmsrl_safe as suggested by Boris.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20150115211702.285038186@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Simplify irq_remapping code by killing irq_remapping_supported() and
related interfaces.

Joerg posted a similar patch at https://lkml.org/lkml/2014/12/15/490,
so assume an signed-off from Joerg.
Signed-off-by: NJiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Tested-by: NJoerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: iommu@lists.linux-foundation.org
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Rientjes <rientjes@google.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Oren Twaig <oren@scalemp.com>
Link: http://lkml.kernel.org/r/1420615903-28253-14-git-send-email-jiang.liu@linux.intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

When interrupt remapping hardware is not in X2APIC, CPU X2APIC mode
will be disabled if:
1) Maximum CPU APIC ID is bigger than 255
2) hypervisior doesn't support x2apic mode.

But we should only check whether hypervisor supports X2APIC mode when
hypervisor(CONFIG_HYPERVISOR_GUEST) is enabled, otherwise X2APIC will
always be disabled when CONFIG_HYPERVISOR_GUEST is disabled and IR
doesn't work in X2APIC mode.
Signed-off-by: NJiang Liu <jiang.liu@linux.intel.com>
Tested-by: NJoerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: iommu@lists.linux-foundation.org
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Rientjes <rientjes@google.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Oren Twaig <oren@scalemp.com>
Link: http://lkml.kernel.org/r/1420615903-28253-12-git-send-email-jiang.liu@linux.intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

If remapping is in XAPIC mode, the setup code just skips X2APIC
initialization without checking max CPU APIC ID in system, which may
cause problem if system has a CPU with APIC ID bigger than 255.

Handle IR in XAPIC mode the same way as if remapping is disabled.

[ tglx: Split out from previous patch ]
Signed-off-by: NJiang Liu <jiang.liu@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: iommu@lists.linux-foundation.org
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Rientjes <rientjes@google.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Oren Twaig <oren@scalemp.com>
Link: http://lkml.kernel.org/r/1420615903-28253-8-git-send-email-jiang.liu@linux.intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Refine enable_IR_x2apic() and related functions for better readability.

[ tglx: Removed the XAPIC mode change and split it out into a seperate
  	patch. Added comments. ]
Signed-off-by: NJiang Liu <jiang.liu@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: iommu@lists.linux-foundation.org
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Rientjes <rientjes@google.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Oren Twaig <oren@scalemp.com>
Link: http://lkml.kernel.org/r/1420615903-28253-8-git-send-email-jiang.liu@linux.intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

X2APIC will be disabled if user specifies "nox2apic" on kernel command
line, even when x2apic_preenabled is true. So correctly detect X2APIC
status by using x2apic_enabled() instead of x2apic_preenabled.
Signed-off-by: NJiang Liu <jiang.liu@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: iommu@lists.linux-foundation.org
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Rientjes <rientjes@google.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Oren Twaig <oren@scalemp.com>
Link: http://lkml.kernel.org/r/1420615903-28253-7-git-send-email-jiang.liu@linux.intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Local variable x2apic_enabled has been assigned to but never referred,
so kill it.
Signed-off-by: NJiang Liu <jiang.liu@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: iommu@lists.linux-foundation.org
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Rientjes <rientjes@google.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Oren Twaig <oren@scalemp.com>
Link: http://lkml.kernel.org/r/1420615903-28253-6-git-send-email-jiang.liu@linux.intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

When kernel doesn't support X2APIC but BIOS has enabled X2APIC, system
may panic or hang without useful messages. On the other hand, it's
hard to dynamically disable X2APIC when CONFIG_X86_X2APIC is disabled.
So panic with a clear message in such a case.

Now system panics as below when X2APIC is disabled and interrupt remapping
is enabled:
[    0.316118] LAPIC pending interrupts after 512 EOI
[    0.322126] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
[    0.368655] Kernel panic - not syncing: timer doesn't work through Interrupt-remapped IO-APIC
[    0.378300] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.18.0+ #340
[    0.385300] Hardware name: Intel Corporation BRICKLAND/BRICKLAND, BIOS BRIVTIN1.86B.0051.L05.1406240953 06/24/2014
[    0.396997]  ffff88046dc03000 ffff88046c307dd8 ffffffff8179dada 00000000000043f2
[    0.405629]  ffffffff81a92158 ffff88046c307e58 ffffffff8179b757 0000000000000002
[    0.414261]  0000000000000008 ffff88046c307e68 ffff88046c307e08 ffffffff813ad82b
[    0.422890] Call Trace:
[    0.425711]  [<ffffffff8179dada>] dump_stack+0x45/0x57
[    0.431533]  [<ffffffff8179b757>] panic+0xc1/0x1f5
[    0.436978]  [<ffffffff813ad82b>] ? delay_tsc+0x3b/0x70
[    0.442910]  [<ffffffff8166fa2c>] panic_if_irq_remap+0x1c/0x20
[    0.449524]  [<ffffffff81d73645>] setup_IO_APIC+0x405/0x82e
[    0.464979]  [<ffffffff81d6fcc2>] native_smp_prepare_cpus+0x2d9/0x31c
[    0.472274]  [<ffffffff81d5d0ac>] kernel_init_freeable+0xd6/0x223
[    0.479170]  [<ffffffff81792ad0>] ? rest_init+0x80/0x80
[    0.485099]  [<ffffffff81792ade>] kernel_init+0xe/0xf0
[    0.490932]  [<ffffffff817a537c>] ret_from_fork+0x7c/0xb0
[    0.497054]  [<ffffffff81792ad0>] ? rest_init+0x80/0x80
[    0.502983] ---[ end Kernel panic - not syncing: timer doesn't work through Interrupt-remapped IO-APIC

System hangs as below when X2APIC and interrupt remapping are both disabled:
[    1.102782] pci 0000:00:02.0: System wakeup disabled by ACPI
[    1.109351] pci 0000:00:03.0: System wakeup disabled by ACPI
[    1.115915] pci 0000:00:03.2: System wakeup disabled by ACPI
[    1.122479] pci 0000:00:03.3: System wakeup disabled by ACPI
[    1.132274] pci 0000:00:1c.0: Enabling MPC IRBNCE
[    1.137620] pci 0000:00:1c.0: Intel PCH root port ACS workaround enabled
[    1.145239] pci 0000:00:1c.0: System wakeup disabled by ACPI
[    1.151790] pci 0000:00:1c.7: Enabling MPC IRBNCE
[    1.157128] pci 0000:00:1c.7: Intel PCH root port ACS workaround enabled
[    1.164748] pci 0000:00:1c.7: System wakeup disabled by ACPI
[    1.171447] pci 0000:00:1e.0: System wakeup disabled by ACPI
[    1.178612] acpiphp: Slot [8] registered
[    1.183095] pci 0000:00:02.0: PCI bridge to [bus 01]
[    1.188867] acpiphp: Slot [2] registered

With this patch applied, the system panics in both cases with a proper
panic message.
Signed-off-by: NJiang Liu <jiang.liu@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: iommu@lists.linux-foundation.org
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Rientjes <rientjes@google.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Oren Twaig <oren@scalemp.com>
Link: http://lkml.kernel.org/r/1420615903-28253-5-git-send-email-jiang.liu@linux.intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

If x2apic got disabled on the kernel command line, then the following
issue can happen:

enable_IR_x2apic()
   ....
   x2apic_mode = 1;
   enable_x2apic();

     if (x2apic_disabled) {
	__disable_x2apic();
	return;
     }

That leaves X2APIC disabled in hardware, but x2apic_mode stays 1. So
all other code which checks x2apic_mode gets the wrong information.

Set x2apic_mode to 0 after disabling it in hardware.

This is just a hotfix. The proper solution is to rework this code so
it has seperate functions for the initial setup on the boot processor
and the secondary cpus, but that's beyond the scope of this fix.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: iommu@lists.linux-foundation.org
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Rientjes <rientjes@google.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Oren Twaig <oren@scalemp.com>

enable_IR_x2apic() calls setup_irq_remapping_ops() which by default
installs the intel dmar remapping ops and then calls the amd iommu irq
remapping prepare callback to figure out whether we are running on an
AMD machine with irq remapping hardware.

Right after that it calls irq_remapping_prepare() which pointlessly
checks:
	if (!remap_ops || !remap_ops->prepare)
               return -ENODEV;
and then calls

    remap_ops->prepare()

which is silly in the AMD case as it got called from
setup_irq_remapping_ops() already a few microseconds ago.

Simplify this and just collapse everything into
irq_remapping_prepare().

The irq_remapping_prepare() remains still silly as it assigns blindly
the intel ops, but that's not scope of this patch.

The scope here is to move the preperatory work, i.e. memory
allocations out of the atomic section which is required to enable irq
remapping.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: NBorislav Petkov <bp@alien8.de>
Acked-and-tested-by: NJoerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: iommu@lists.linux-foundation.org
Cc: Joerg Roedel <jroedel@suse.de>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Oren Twaig <oren@scalemp.com>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/20141205084147.232633738@linutronix.de
Link: http://lkml.kernel.org/r/1420615903-28253-2-git-send-email-jiang.liu@linux.intel.comSigned-off-by: NJiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

In v3.19-rc3 tree when CONFIG_ARM_LPAE and CONFIG_DEBUG_RODATA are enabled
image failed to compile with the following error:

arch/arm/mm/init.c:661:14: error: ‘PMD_SECT_RDONLY’ undeclared here (not in a function)

It seems that '80d6b0c2 ARM: mm: allow text and rodata sections to be read-only'
and 'ded94779 ARM: 8109/1: mm: Modify pte_write and pmd_write logic for LPAE'
commits crossed. 80d6b0c2 uses PMD_SECT_RDONLY macro but ded94779 renames it
and uses software bits L_PMD_SECT_RDONLY instead.

Fix is to use L_PMD_SECT_RDONLY instead PMD_SECT_RDONLY as ded94779 does in
another places.
Signed-off-by: NVictor Kamensky <victor.kamensky@linaro.org>
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

There was another report of a boot failure with a #GP fault in the
uncore SBOX initialization. The earlier work around was not enough
for this system.

The boot was failing while trying to initialize the third SBOX.

This patch detects parts with only two SBOXes and limits the number
of SBOX units to two there.

Stable material, as it affects boot problems on 3.18.
Tested-by: NAndreas Oehler <andreas@oehler-net.de>
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Yan, Zheng <zheng.z.yan@intel.com>
Link: http://lkml.kernel.org/r/1420583675-9163-1-git-send-email-andi@firstfloor.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Perf reports user regs for kernel-mode samples so that samples can
be backtraced through user code.  The old code was very broken in
syscall context, resulting in useless backtraces.

The new code, in contrast, is still dangerously racy, but it should
at least work most of the time.
Tested-by: NJiri Olsa <jolsa@kernel.org>
Signed-off-by: NAndy Lutomirski <luto@amacapital.net>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: chenggang.qcg@taobao.com
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/243560c26ff0f739978e2459e203f6515367634d.1420396372.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

On x86_64, at least, task_pt_regs may be only partially initialized
in many contexts, so x86_64 should not use it without extra care
from interrupt context, let alone NMI context.

This will allow x86_64 to override the logic and will supply some
scratch space to use to make a cleaner copy of user regs.
Tested-by: NJiri Olsa <jolsa@kernel.org>
Signed-off-by: NAndy Lutomirski <luto@amacapital.net>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: chenggang.qcg@taobao.com
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Jean Pihet <jean.pihet@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Salter <msalter@redhat.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/e431cd4c18c2e1c44c774f10758527fb2d1025c4.1420396372.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

Stephane reported that the PEBS fixup was broken by the recent commit to
the instruction decoder. The thing had an off-by-one which resulted in
not being able to decode the last instruction and always bail.
Reported-by: NStephane Eranian <eranian@google.com>
Fixes: 6ba48ff4 ("x86: Remove arbitrary instruction size limit in instruction decoder")
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org # 3.18
Cc: <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Liang Kan <kan.liang@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Link: http://lkml.kernel.org/r/20141216104614.GV3337@twins.programming.kicks-ass.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

build error

  arch/blackfin/mach-bf533/boards/stamp.c:834:2: error: implicit declaration of function 'mdelay'
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Reported-by: NWu Fengguang <fengguang.wu@intel.com>
Acked-by: NMike Frysinger <vapier@gentoo.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The early ioremap support introduced by patch bf4b558e
("arm64: add early_ioremap support") failed to add a call to
early_ioremap_reset() at an appropriate time. Without this call,
invocations of early_ioremap etc. that are done too late will go
unnoticed and may cause corruption.

This is exactly what happened when the first user of this feature
was added in patch f84d0275 ("arm64: add EFI runtime services").
The early mapping of the EFI memory map is unmapped during an early
initcall, at which time the early ioremap support is long gone.

Fix by adding the missing call to early_ioremap_reset() to
setup_arch(), and move the offending early_memunmap() to right after
the point where the early mapping of the EFI memory map is last used.

Fixes: f84d0275 ("arm64: add EFI runtime services")
Cc: <stable@vger.kernel.org>
Signed-off-by: NLeif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Now local variables kernel_x_start and kernel_x_end defined using
'unsigned long' type which is wrong because they represent physical
memory range and will be calculated wrongly if LPAE is enabled.
As result, all following code in map_lowmem() will not work correctly.

For example, Keystone 2 boot is broken because
 kernel_x_start == 0x0000 0000
 kernel_x_end   == 0x0080 0000

instead of
 kernel_x_start == 0x0000 0008 0000 0000
 kernel_x_end   == 0x0000 0008 0080 0000
and as result whole low memory will be mapped with MT_MEMORY_RW
permissions by code (start > kernel_x_end):
		} else if (start >= kernel_x_end) {
			map.pfn = __phys_to_pfn(start);
			map.virtual = __phys_to_virt(start);
			map.length = end - start;
			map.type = MT_MEMORY_RW;

			create_mapping(&map);
		}

Hence, fix it by using phys_addr_t type for variables kernel_x_start
and kernel_x_end.
Tested-by: NMurali Karicheri <m-karicheri2@ti.com>
Signed-off-by: NGrygorii Strashko <grygorii.strashko@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Currently the arm page table dumping code starts dumping page tables
from USER_PGTABLES_CEILING. This is unnecessary for skipping any entries
related to userspace as the swapper_pg_dir does not contain such
entries, and results in a couple of unfortuante side effects.

Firstly, any kernel mappings which might exist below
USER_PGTABLES_CEILING will not be accounted in the dump output. This
masks any entries erroneously created below this address.

Secondly, if the final page table entry walked is part of a valid
mapping the page table dumping code will not log the region this entry
is part of, as the final note_page call in walk_pgd will trigger an
early return when 0 < USER_PGTABLES_CEILING. Luckily this isn't seen on
contemporary systems as they typically don't have enough RAM to extend
the linear mapping right to the end of the address space.

Due to the way addr is constructed in the walk_* functions, it can never
be less than USER_PGTABLES_CEILING when walking the page tables, so it
is not necessary to avoid dereferencing invalid table addresses. The
existing checks for st->current_prot and st->marker[1].start_address are
sufficient to ensure we will not print and/or dereference garbage when
trying to log information.

This patch removes both problematic uses of USER_PGTABLES_CEILING from
the arm page table dumping code, preventing both of these issues. We
will now report any low mappings, and the final note_page call will not
return early, ensuring all regions are logged.
Signed-off-by: NMark Rutland <mark.rutland@arm.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

On next-20150105, defconfig compilation breaks with:

arch/arm64/kernel/smp_spin_table.c:80:2: error: implicit declaration of function ‘ioremap_cache’ [-Werror=implicit-function-declaration]
arch/arm64/kernel/smp_spin_table.c:92:2: error: implicit declaration of function ‘writeq_relaxed’ [-Werror=implicit-function-declaration]
arch/arm64/kernel/smp_spin_table.c:101:2: error: implicit declaration of function ‘iounmap’ [-Werror=implicit-function-declaration]

Fix by including asm/io.h, which contains definitions or prototypes
for these macros or functions.

This second version incorporates a comment from Mark Rutland
<mark.rutland@arm.com> to keep the includes in alphabetical order
by filename.
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Cc: Paul Walmsley <pwalmsley@nvidia.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Acked-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

On next-20150105, defconfig compilation breaks with:

arch/arm64/kernel/module.c:408:4: error: implicit declaration of function ‘apply_alternatives’ [-Werror=implicit-function-declaration]

Fix by including asm/alternative.h, where the apply_alternatives()
prototype is declared.

This second version incorporates a comment from Mark Rutland
<mark.rutland@arm.com> to keep the includes in alphabetical order
by filename.
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Cc: Paul Walmsley <pwalmsley@nvidia.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Acked-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

On next-20150105, defconfig compilation breaks with:

./arch/arm64/include/asm/arch_timer.h:112:2: error: implicit declaration of function ‘BUG’ [-Werror=implicit-function-declaration]

Fix by including linux/bug.h, where the BUG macro is defined.

This second version incorporates a comment from Mark Rutland
<mark.rutland@arm.com> to keep the includes in alphabetical order
by filename.
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Cc: Paul Walmsley <pwalmsley@nvidia.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Acked-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

On next-20150105, defconfig compilation breaks with:

./arch/arm64/include/asm/processor.h:47:32: error: ‘PHYS_MASK’ undeclared (first use in this function)

Fix by including asm/pgtable-hwdef.h, where PHYS_MASK is defined.

This second version incorporates a comment from Mark Rutland
<mark.rutland@arm.com> to keep the includes in alphabetical order
by filename.
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Cc: Paul Walmsley <pwalmsley@nvidia.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Acked-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>