ACPI irq source overrides are allowed for the 16 isa irqs and are
allowed to map any gsi to any isa irq.  A few motherboards have been
seen to take advantage of this and put the isa irqs on the 2nd or
3rd ioapic.  This causes some problems, most notably the fact
that we can not use any gsi < 16.

To correct this move the gsis that are not isa irqs and have
a gsi number < 16 into the linux irq space just past gsi_end.
This is what the es7000 platform is doing today.  Moving only the
low 16 gsis above the rest of the gsi's only penalizes weird
platforms, leaving sane acpi implementations with a 1-1 mapping
of gsis and irqs.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
LKML-Reference: <1269936436-7039-14-git-send-email-ebiederm@xmission.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Use the global gsi_end value now that all ioapics have
valid gsi numbers instead of a combination of acpi_probe_gsi
and walking all of the ioapics and couting their number of
entries by hand if acpi_probe_gsi gave us an answer we did
not like.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
LKML-Reference: <1269936436-7039-13-git-send-email-ebiederm@xmission.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Now that all ioapics have valid gsi_base values use this to
accellerate pin_2_irq.  In the case of acpi this also ensures
that pin_2_irq will compute the same irq value for an ioapic
pin as acpi will.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
LKML-Reference: <1269936436-7039-12-git-send-email-ebiederm@xmission.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Now that all ioapic registration happens in mp_register_ioapic we can
move the calculation of nr_ioapic_registers there from enable_IO_APIC.
The number of ioapic registers is already calucated in mp_register_ioapic
so all that really needs to be done is to save the caluclated value
in nr_ioapic_registers.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
LKML-Reference: <1269936436-7039-11-git-send-email-ebiederm@xmission.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Long ago MP_ioapic_info was the primary way of setting up our
ioapic data structures and mp_register_ioapic was a compatibility
shim for acpi code.  Now the situation is reversed and
and mp_register_ioapic is the primary way of setting up our
ioapic data structures.

Keep the setting up of ioapic data structures uniform by
having mp_register_ioapic call mp_register_ioapic.

This changes a few fields:

- type: is now hardset to MP_IOAPIC but type had to
  bey MP_IOAPIC or MP_ioapic_info would not have been called.

- flags: is now hard coded to MPC_APIC_USABLE.
  We require flags to contain at least MPC_APIC_USEBLE in
  MP_ioapic_info and we don't ever examine flags so dropping
  a few flags that might possibly exist that we have never
  used is harmless.

- apicaddr: Unchanged

- apicver: Read from the ioapic instead of using the cached
  hardware value in the MP table.  The real hardware value
  will be more accurate.

- apicid: Now verified to be unique and changed if it is not.
  If the BIOS got this right this is a noop.  If the BIOS did
  not fixing things appears to be the better solution.

This adds gsi_base and gsi_end values to our ioapics defined with
the mpatable, which will make our lives simpler later since
we can always assume gsi_base and gsi_end are valid.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
LKML-Reference: <1269936436-7039-10-git-send-email-ebiederm@xmission.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Add the global variable gsi_end and teach mp_register_ioapic
to keep it uptodate as we add more ioapics into the system.

ioapics can only be added early in boot so the code that
runs later can treat gsi_end as a constant.

Remove the have hacks in sfi.c to second guess mp_register_ioapic
by keeping t's own running total of how many gsi's have been seen,
and instead use the gsi_end.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
LKML-Reference: <1269936436-7039-9-git-send-email-ebiederm@xmission.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

This patches fixes the types of gsi_base and gsi_end values in
struct mp_ioapic_gsi, and the gsi parameter of mp_find_ioapic
and mp_find_ioapic_pin

A gsi is cannonically a u32, not an int.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
LKML-Reference: <1269936436-7039-8-git-send-email-ebiederm@xmission.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

io_apic_redir_entries has a huge conceptual bug.  It returns the maximum
redirection entry not the number of redirection entries.  Which simply
does not match what the name of the function.  This just caught me
and it caught  Feng Tang, and  Len Brown when they wrote sfi_parse_ioapic.

Modify io_apic_redir_entries to actually return the number of redirection
entries, and fix the callers so that they properly handle receiving the
number of the number of redirection table entries, instead of the
number of redirection table entries less one.

While the usage in sfi.c does not show up in this patch it is fixed
by virtue of the fact that io_apic_redir_entries now has the semantics
sfi_parse_ioapic most reasonably expects.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
LKML-Reference: <1269936436-7039-7-git-send-email-ebiederm@xmission.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Remove the assumption that there is not an override for isa irq 0.
Instead lookup the gsi and from that lookup the ioapic and pin of each
isa irq indivdually.

In general this should not have any behavioural affect but in
perverse cases this gets all of the details correct, instead of
doing something weird.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
LKML-Reference: <1269936436-7039-5-git-send-email-ebiederm@xmission.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Currently acpi_sci_ioapic_setup calls mp_override_legacy_irq with
bus_irq == gsi, which is wrong if we are comming from an override
Instead pass the bus_irq into acpi_sci_ioapic_setup.

This fix was inspired by a similar fix from:
Yinghai Lu <yinghai@kernel.org>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
LKML-Reference: <1269936436-7039-4-git-send-email-ebiederm@xmission.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

In perverse acpi implementations the isa irqs are not identity mapped
to the first 16 gsi.  Furthermore at least the extended interrupt
resource capability may return gsi's and not isa irqs.  So since
what we get from acpi is a gsi teach acpi_get_overrride_irq to
operate on a gsi instead of an isa_irq.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
LKML-Reference: <1269936436-7039-2-git-send-email-ebiederm@xmission.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

There are a number of cases where the current code makes the assumption
that isa irqs identity map to the first 16 acpi global system intereupts.
In most instances that assumption is correct as that is the required
behaviour in dual i8259 mode and the default behavior in ioapic mode.

However there are some systems out there that take advantage of acpis
interrupt remapping  for the isa irqs to have a completely different
mapping of isa_irq to gsi.

Introduce acpi_isa_irq_to_gsi to perform this mapping explicitly in the
code that needs it.  Initially this will be just the current assumed
identity mapping to ensure it's introduction does not cause regressions.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
LKML-Reference: <1269936436-7039-1-git-send-email-ebiederm@xmission.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

This is a standalone version of VMware Balloon driver.  Ballooning is a
technique that allows hypervisor dynamically limit the amount of memory
available to the guest (with guest cooperation).  In the overcommit
scenario, when hypervisor set detects that it needs to shuffle some
memory, it instructs the driver to allocate certain number of pages, and
the underlying memory gets returned to the hypervisor.  Later hypervisor
may return memory to the guest by reattaching memory to the pageframes and
instructing the driver to "deflate" balloon.

We are submitting a standalone driver because KVM maintainer (Avi Kivity)
expressed opinion (rightly) that our transport does not fit well into
virtqueue paradigm and thus it does not make much sense to integrate with
virtio.

There were also some concerns whether current ballooning technique is the
right thing.  If there appears a better framework to achieve this we are
prepared to evaluate and switch to using it, but in the meantime we'd like
to get this driver upstream.

We want to get the driver accepted in distributions so that users do not
have to deal with an out-of-tree module and many distributions have
"upstream first" requirement.

The driver has been shipping for a number of years and users running on
VMware platform will have it installed as part of VMware Tools even if it
will not come from a distribution, thus there should not be additional
risk in pulling the driver into mainline.  The driver will only activate
if host is VMware so everyone else should not be affected at all.
Signed-off-by: NDmitry Torokhov <dtor@vmware.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Atom erratum AAE44/AAF40/AAG38/AAH41:

"If software clears the PS (page size) bit in a present PDE (page
directory entry), that will cause linear addresses mapped through this
PDE to use 4-KByte pages instead of using a large page after old TLB
entries are invalidated. Due to this erratum, if a code fetch uses
this PDE before the TLB entry for the large page is invalidated then
it may fetch from a different physical address than specified by
either the old large page translation or the new 4-KByte page
translation. This erratum may also cause speculative code fetches from
incorrect addresses."

[http://download.intel.com/design/processor/specupdt/319536.pdf]

Where as commit 211b3d03 seems to
workaround errata AAH41 (mixed 4K TLBs) it reduces the window of
opportunity for the bug to occur and does not totally remove it.  This
patch disables mixed 4K/4MB page tables totally avoiding the page
splitting and not tripping this processor issue.

This is based on an original patch by Colin King.
Originally-by: NColin Ian King <colin.king@canonical.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
LKML-Reference: <1269271251-19775-1-git-send-email-colin.king@canonical.com>
Cc: <stable@kernel.org>

When we do a thread switch, we clear the outgoing FS/GS base if the
corresponding selector is nonzero.  This is taken by __switch_to() as
an entry invariant; it does not verify that it is true on entry.
However, copy_thread() doesn't enforce this constraint, which can
result in inconsistent results after fork().

Make copy_thread() match the behavior of __switch_to().
Reported-and-tested-by: NSamuel Thibault <samuel.thibault@inria.fr>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
LKML-Reference: <4BD1E061.8030605@zytor.com>
Cc: <stable@kernel.org>

APB timer is used on Moorestown platforms but not on a standard PC.
If APB timer code is compiled in but not initialized at run-time due
to lack of FW reported SFI table, kernel would panic when the non-boot
CPUs are offlined and notifier is called.

https://bugzilla.kernel.org/show_bug.cgi?id=15786

This patch ensures CPU hotplug notifier for APB timer is only registered
when the APBT timer block is initialized.
Signed-off-by: NJacob Pan <jacob.jun.pan@linux.intel.com>
LKML-Reference: <1271701423-1162-1-git-send-email-jacob.jun.pan@linux.intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

When we fetch the hot regs and rewind to the nth caller, it
might happen that we dereference a frame pointer outside the
kernel stack boundaries, like in this example:

	perf_trace_sched_switch+0xd5/0x120
        schedule+0x6b5/0x860
        retint_careful+0xd/0x21

Since we directly dereference a userspace frame pointer here while
rewinding behind retint_careful, this may end up in a crash.

Fix this by simply using probe_kernel_address() when we rewind the
frame pointer.

This issue will have a much more proper fix in the next version of the
perf_arch_fetch_caller_regs() API that will only need to rewind to the
first caller.
Reported-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Tested-by: NEric Dumazet <eric.dumazet@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: David Miller <davem@davemloft.net>
Cc: Archs <linux-arch@vger.kernel.org>

If we boot into a crash-kernel the gart might still be
enabled and its caches might be dirty. This can result in
undefined behavior later. Fix it by explicitly disabling the
gart hardware before initialization and flushing the caches
after enablement.
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

Replace open coded version with for_each_pci_dev
Signed-off-by: NChris Wright <chrisw@sous-sol.org>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

This effectively reverts commit 61d047be.

Disabling the IOMMU can potetially allow DMA transactions to
complete without being translated.  Leave it enabled, and allow
crash kernel to do the IOMMU reinitialization properly.

Cc: stable@kernel.org
Cc: Joerg Roedel <joerg.roedel@amd.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: NChris Wright <chrisw@sous-sol.org>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

To catch future potential issues we can add a warning whenever we issue
a command before the command buffer is fully initialized.
Signed-off-by: NChris Wright <chrisw@sous-sol.org>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

Hit another kdump problem as reported by Neil Horman.  When initializaing
the IOMMU, we attach devices to their domains before the IOMMU is
fully (re)initialized.  Attaching a device will issue some important
invalidations.  In the context of the newly kexec'd kdump kernel, the
IOMMU may have stale cached data from the original kernel.  Because we
do the attach too early, the invalidation commands are placed in the new
command buffer before the IOMMU is updated w/ that buffer.  This leaves
the stale entries in the kdump context and can renders device unusable.
Simply enable the IOMMU before we do the attach.

Cc: stable@kernel.org
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: NChris Wright <chrisw@sous-sol.org>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

According to Intel Software Devel Manual Volume 3B, the
Nehalem-EX PMU is just like regular Nehalem (except for the
uncore support, which is completely different).
Signed-off-by: NVince Weaver <vweaver1@eecs.utk.edu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Lin Ming <ming.m.lin@intel.com>
LKML-Reference: <alpine.DEB.2.00.1004060956580.1417@cl320.eecs.utk.edu>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Jan Grossmann reported kernel boot panic while booting SMP
kernel on his system with a single core cpu. SMP kernels call
enable_IR_x2apic() from native_smp_prepare_cpus() and on
platforms where the kernel doesn't find SMP configuration we
ended up again calling enable_IR_x2apic() from the
APIC_init_uniprocessor() call in the smp_sanity_check(). Thus
leading to kernel panic.

Don't call enable_IR_x2apic() and default_setup_apic_routing()
from APIC_init_uniprocessor() in CONFIG_SMP case.

NOTE: this kind of non-idempotent and assymetric initialization
sequence is rather fragile and unclean, we'll clean that up
in v2.6.35. This is the minimal fix for v2.6.34.

Reported-by: Jan.Grossmann@kielnet.net
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: <jbarnes@virtuousgeek.org>
Cc: <david.woodhouse@intel.com>
Cc: <weidong.han@intel.com>
Cc: <youquan.song@intel.com>
Cc: <Jan.Grossmann@kielnet.net>
Cc: <stable@kernel.org> # [v2.6.32.x, v2.6.33.x]
LKML-Reference: <1270083887.7835.78.camel@sbs-t61.sc.intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

When profiling a 32-bit process on a 64-bit kernel, callgraph tracing
stopped after the first function, because it has seen a garbage memory
address (tried to interpret the frame pointer, and return address as a
64-bit pointer).

Fix this by using a struct stack_frame with 32-bit pointers when the
TIF_IA32 flag is set.

Note that TIF_IA32 flag must be used, and not is_compat_task(), because
the latter is only set when the 32-bit process is executing a syscall,
which may not always be the case (when tracing page fault events for
example).
Signed-off-by: NTörök Edwin <edwintorok@gmail.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
LKML-Reference: <1268820436-13145-1-git-send-email-edwintorok@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Commit 3f6da390 ("perf: Rework and fix the arch CPU-hotplug hooks") moved
the amd northbridge allocation from CPUS_ONLINE to CPUS_PREPARE_UP
however amd_nb_id() doesn't work yet on prepare so it would simply bail
basically reverting to a state where we do not properly track node wide
constraints - causing weird perf results.

Fix up the AMD NorthBridge initialization code by allocating from
CPU_UP_PREPARE and installing it from CPU_STARTING once we have the
proper nb_id. It also properly deals with the allocation failing.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
[ robustify using amd_has_nb() ]
Signed-off-by: NStephane Eranian <eranian@google.com>
LKML-Reference: <1269353485.5109.48.camel@twins>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Because we need to have cpu identification things done by the time we run
CPU_STARTING notifiers.

( This init ordering will be relied on by the next fix. )
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1269353485.5109.48.camel@twins>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This allows arch code could decide the way to reserve the ibft.

And we should reserve ibft as early as possible, instead of BOOTMEM
stage, in case the table is in RAM range and is not reserved by BIOS
(this will often be the case.)

Move to just after find_smp_config().

Also when CONFIG_NO_BOOTMEM=y, We will not have reserve_bootmem() anymore.

-v2: fix typo about ibft pointed by Konrad Rzeszutek Wilk <konrad@darnok.org>
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
LKML-Reference: <4BB510FB.80601@kernel.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Peter Jones <pjones@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad@kernel.org>
CC: Jan Beulich <jbeulich@novell.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

We think there exists a bug in the HPET code that emulates the RTC.

In the normal case, when the RTC frequency is set, the rtc driver tells
the hpet code about it here:

int hpet_set_periodic_freq(unsigned long freq)
{
        uint64_t clc;

        if (!is_hpet_enabled())
                return 0;

        if (freq <= DEFAULT_RTC_INT_FREQ)
                hpet_pie_limit = DEFAULT_RTC_INT_FREQ / freq;
        else {
                clc = (uint64_t) hpet_clockevent.mult * NSEC_PER_SEC;
                do_div(clc, freq);
                clc >>= hpet_clockevent.shift;
                hpet_pie_delta = (unsigned long) clc;
        }
        return 1;
}

If freq is set to 64Hz (DEFAULT_RTC_INT_FREQ) or lower, then
hpet_pie_limit (a static) is set to non-zero.  Then, on every one-shot
HPET interrupt, hpet_rtc_timer_reinit is called to compute the next
timeout.  Well, that function has this logic:

        if (!(hpet_rtc_flags & RTC_PIE) || hpet_pie_limit)
                delta = hpet_default_delta;
        else
                delta = hpet_pie_delta;

Since hpet_pie_limit is not 0, hpet_default_delta is used.  That
corresponds to 64Hz.

Now, if you set a different rtc frequency, you'll take the else path
through hpet_set_periodic_freq, but unfortunately no one resets
hpet_pie_limit back to 0.

Boom....now you are stuck with 64Hz RTC interrupts forever.

The patch below just resets the hpet_pie_limit value when requested freq
is greater than DEFAULT_RTC_INT_FREQ, which we think fixes this problem.
Signed-off-by: NAlok N Kataria <akataria@vmware.com>
LKML-Reference: <201003112200.o2BM0Hre012875@imap1.linux-foundation.org>
Signed-off-by: NDaniel Hecht <dhecht@vmware.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

On Wed, Feb 24, 2010 at 03:37:04PM -0800, Justin Piszcz wrote:
> Hello,
>
> Again, on the Intel DP55KG board:
>
> # uname -a
> Linux host 2.6.33 #1 SMP Wed Feb 24 18:31:00 EST 2010 x86_64 GNU/Linux
>
> [    1.237600] ------------[ cut here ]------------
> [    1.237890] WARNING: at arch/x86/kernel/hpet.c:404 hpet_next_event+0x70/0x80()
> [    1.238221] Hardware name:
> [    1.238504] hpet: compare register read back failed.
> [    1.238793] Modules linked in:
> [    1.239315] Pid: 0, comm: swapper Not tainted 2.6.33 #1
> [    1.239605] Call Trace:
> [    1.239886]  <IRQ>  [<ffffffff81056c13>] ? warn_slowpath_common+0x73/0xb0
> [    1.240409]  [<ffffffff81079608>] ? tick_dev_program_event+0x38/0xc0
> [    1.240699]  [<ffffffff81056cb0>] ? warn_slowpath_fmt+0x40/0x50
> [    1.240992]  [<ffffffff81079608>] ? tick_dev_program_event+0x38/0xc0
> [    1.241281]  [<ffffffff81041ad0>] ? hpet_next_event+0x70/0x80
> [    1.241573]  [<ffffffff81079608>] ? tick_dev_program_event+0x38/0xc0
> [    1.241859]  [<ffffffff81078e32>] ? tick_handle_oneshot_broadcast+0xe2/0x100
> [    1.246533]  [<ffffffff8102a67a>] ? timer_interrupt+0x1a/0x30
> [    1.246826]  [<ffffffff81085499>] ? handle_IRQ_event+0x39/0xd0
> [    1.247118]  [<ffffffff81087368>] ? handle_edge_irq+0xb8/0x160
> [    1.247407]  [<ffffffff81029f55>] ? handle_irq+0x15/0x20
> [    1.247689]  [<ffffffff810294a2>] ? do_IRQ+0x62/0xe0
> [    1.247976]  [<ffffffff8146be53>] ? ret_from_intr+0x0/0xa
> [    1.248262]  <EOI>  [<ffffffff8102f277>] ? mwait_idle+0x57/0x80
> [    1.248796]  [<ffffffff8102645c>] ? cpu_idle+0x5c/0xb0
> [    1.249080] ---[ end trace db7f668fb6fef4e1 ]---
>
> Is this something Intel has to fix or is it a bug in the kernel?

This is a chipset erratum.

Thomas: You mentioned we can retain this check only for known-buggy and
hpet debug kind of options. But here is the simple workaround patch for
this particular erratum.

Some chipsets have a erratum due to which read immediately following a
write of HPET comparator returns old comparator value instead of most
recently written value.

Erratum 15 in
"Intel I/O Controller Hub 9 (ICH9) Family Specification Update"
(http://www.intel.com/assets/pdf/specupdate/316973.pdf)

Workaround for the errata is to read the comparator twice if the first
one fails.
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
LKML-Reference: <20100225185348.GA9674@linux-os.sc.intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@gmail.com>
Cc: <stable@kernel.org>

We found a system where the MP table MPC and MPF structures overlap.

That doesn't really matter because the mptable is not used anyways with ACPI,
but it leads to a panic in the early allocator due to the overlapping
reservations in 2.6.33.

Earlier kernels handled this without problems.

Simply change these reservations to reserve_early_overlap_ok to avoid
the panic.
Reported-by: NThomas Renninger <trenn@suse.de>
Tested-by: NThomas Renninger <trenn@suse.de>
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
LKML-Reference: <20100329074111.GA22821@basil.fritz.box>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Cc: <stable@kernel.org>

It is required to call hw_breakpoint_init() on an attr before using it
in any other calls.  This fixes the problem where kgdb will sometimes
fail to initialize on x86_64.
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: 2.6.33 <stable@kernel.org>
LKML-Reference: <1269975907-27602-1-git-send-email-jason.wessel@windriver.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

Scheduler's task migration events don't work because they always
pass NULL regs perf_sw_event(). The event hence gets filtered
in perf_swevent_add().

Scheduler's context switches events use task_pt_regs() to get
the context when the event occured which is a wrong thing to
do as this won't give us the place in the kernel where we went
to sleep but the place where we left userspace. The result is
even more wrong if we switch from a kernel thread.

Use the hot regs snapshot for both events as they belong to the
non-interrupt/exception based events family. Unlike page faults
or so that provide the regs matching the exact origin of the event,
we need to save the current context.

This makes the task migration event working and fix the context
switch callchains and origin ip.

Example: perf record -a -e cs

Before:

    10.91%      ksoftirqd/0                  0  [k] 0000000000000000
                |
                --- (nil)
                    perf_callchain
                    perf_prepare_sample
                    __perf_event_overflow
                    perf_swevent_overflow
                    perf_swevent_add
                    perf_swevent_ctx_event
                    do_perf_sw_event
                    __perf_sw_event
                    perf_event_task_sched_out
                    schedule
                    run_ksoftirqd
                    kthread
                    kernel_thread_helper

After:

    23.77%  hald-addon-stor  [kernel.kallsyms]  [k] schedule
            |
            --- schedule
               |
               |--60.00%-- schedule_timeout
               |          wait_for_common
               |          wait_for_completion
               |          blk_execute_rq
               |          scsi_execute
               |          scsi_execute_req
               |          sr_test_unit_ready
               |          |
               |          |--66.67%-- sr_media_change
               |          |          media_changed
               |          |          cdrom_media_changed
               |          |          sr_block_media_changed
               |          |          check_disk_change
               |          |          cdrom_open

v2: Always build perf_arch_fetch_caller_regs() now that software
events need that too. They don't need it from modules, unlike trace
events, so we keep the EXPORT_SYMBOL in trace_event_perf.c
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>

Rusty found on lguest with trim_bios_range, max_pfn is not right anymore, and
looks e820_remove_range does not work right.

[    0.000000] BIOS-provided physical RAM map:
[    0.000000]  LGUEST: 0000000000000000 - 0000000004000000 (usable)
[    0.000000] Notice: NX (Execute Disable) protection missing in CPU or disabled in BIOS!
[    0.000000] DMI not present or invalid.
[    0.000000] last_pfn = 0x3fa0 max_arch_pfn = 0x100000
[    0.000000] init_memory_mapping: 0000000000000000-0000000003fa0000

root cause is: the e820_remove_range doesn't handle the all covered
case.  e820_remove_range(BIOS_START, BIOS_END - BIOS_START, ...)
produces a bogus range as a result.

Make it match e820_update_range() by handling that case too.
Reported-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Tested-by: NRusty Russell <rusty@rustcorp.com.au>
LKML-Reference: <4BB18E55.6090903@kernel.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

When CONFIG_NO_BOOTMEM=y, it could use memory more effiently, or
in a more compact fashion.

Example:

 Allocated new RAMDISK: 00ec2000 - 0248ce57
 Move RAMDISK from 000000002ea04000 - 000000002ffcee56 to 00ec2000 - 0248ce56

The new RAMDISK's end is not page aligned.
Last page could be shared with other users.

When free_init_pages are called for initrd or .init, the page
could be freed and we could corrupt other data.

code segment in free_init_pages():

 |        for (; addr < end; addr += PAGE_SIZE) {
 |                ClearPageReserved(virt_to_page(addr));
 |                init_page_count(virt_to_page(addr));
 |                memset((void *)(addr & ~(PAGE_SIZE-1)),
 |                        POISON_FREE_INITMEM, PAGE_SIZE);
 |                free_page(addr);
 |                totalram_pages++;
 |        }

last half page could be used as one whole free page.

So page align the boundaries.

-v2: make the original initramdisk to be aligned, according to
     Johannes, otherwise we have the chance to lose one page.
     we still need to keep initrd_end not aligned, otherwise it could
     confuse decompressor.
-v3: change to WARN_ON instead, suggested by Johannes.
-v4: use PAGE_ALIGN, suggested by Johannes.
     We may fix that macro name later to PAGE_ALIGN_UP, and PAGE_ALIGN_DOWN
     Add comments about assuming ramdisk start is aligned
     in relocate_initrd(), change to re get ramdisk_image instead of save it
     to make diff smaller. Add warning for wrong range, suggested by Johannes.
-v6: remove one WARN()
     We need to align beginning in free_init_pages()
     do not copy more than ramdisk_size, noticed by Johannes
Reported-by: NStanislaw Gruszka <sgruszka@redhat.com>
Tested-by: NStanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Cc: David Miller <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <1269830604-26214-3-git-send-email-yinghai@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Fix:

 ------------[ cut here ]------------
 WARNING: at arch/x86/mm/init.c:342 free_init_pages+0x4c/0xfa()
 free_init_pages: range [0x40daf000, 0x40db5c24] is not aligned
 Modules linked in:
 Pid: 0, comm: swapper Not tainted
 2.6.34-rc2-tip-03946-g4f16b23-dirty #50 Call Trace:
  [<40232e9f>] warn_slowpath_common+0x65/0x7c
  [<4021c9f0>] ? free_init_pages+0x4c/0xfa
  [<40881434>] ? _etext+0x0/0x24
  [<40232eea>] warn_slowpath_fmt+0x24/0x27
  [<4021c9f0>] free_init_pages+0x4c/0xfa
  [<40881434>] ? _etext+0x0/0x24
  [<40d3f4bd>] alternative_instructions+0xf6/0x100
  [<40d3fe4f>] check_bugs+0xbd/0xbf
  [<40d398a7>] start_kernel+0x2d5/0x2e4
  [<40d390ce>] i386_start_kernel+0xce/0xd5
 ---[ end trace 4eaa2a86a8e2da22 ]---

Comments in vmlinux.lds.S already said:

 |        /*
 |         * smp_locks might be freed after init
 |         * start/end must be page aligned
 |         */
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Cc: David Miller <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <1269830604-26214-2-git-send-email-yinghai@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Commit 3f6da390
(perf: Rework and fix the arch CPU-hotplug hooks) broke suspend to
RAM on my HP nx6325 (and most likely on other AMD-based boxes too)
by allowing amd_pmu_cpu_offline() to be executed for CPUs that are
going offline as part of the suspend process.  The problem is that
cpuhw->amd_nb may be NULL already, so the function should make sure
it's not NULL before accessing the object pointed to by it.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently c1e_idle returns true for all CPUs greater than or equal to
family 0xf model 0x40. This covers too many CPUs.

Meanwhile a respective erratum for the underlying problem was filed
(#400). This patch adds the logic to check whether erratum #400
applies to a given CPU.
Especially for CPUs where SMI/HW triggered C1e is not supported,
c1e_idle() doesn't need to be used. We can check this by looking at
the respective OSVW bit for erratum #400.

Cc: <stable@kernel.org> # .32.x .33.x
Signed-off-by: NAndreas Herrmann <andreas.herrmann3@amd.com>
LKML-Reference: <20100319110922.GA19614@alberich.amd.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

perf_arch_fetch_caller_regs() is exported for the overriden x86
version, but not for the generic weak version.

As a general rule, weak functions should not have their symbol
exported in the same file they are defined.

So let's export it on trace_event_perf.c as it is used by trace
events only.

This fixes:

	ERROR: ".perf_arch_fetch_caller_regs" [fs/xfs/xfs.ko] undefined!
	ERROR: ".perf_arch_fetch_caller_regs" [arch/powerpc/platforms/cell/spufs/spufs.ko] undefined!

-v2: And also only build it if trace events are enabled.
-v3: Fix changelog mistake
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1268697902-9518-1-git-send-regression-fweisbec@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>