In the CONFIG_AUDITSYSCALL fast-path for x86 64-bit system calls,
we can pass a bad return value and/or error indication for the
system call to audit_syscall_exit().  This happens when
TIF_NEED_RESCHED was set as the system call returned, so we went
out to schedule() and came back to the exit-audit fast-path.  The
fix is to reload the user return value register from the pt_regs
before using it for audit_syscall_exit().

Both the 32-bit kernel's fast path and the 64-bit kernel's 32-bit
system call fast paths work slightly differently, so that they
always leave the fast path entirely to reschedule and don't return
there, so they don't have the analogous bugs.
Reported-by: NAlexander Viro <aviro@redhat.com>
Signed-off-by: NRoland McGrath <roland@redhat.com>

Pointed out by Lucas who found the new one in a comment in
setup_percpu.c. And then I fixed the others that I grepped
for.
Reported-by: NLucas <canolucas@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit e534c7c5 ("numa: x86_64: use generic percpu var
numa_node_id() implementation") broke numa systems that don't have ram
on node0 when MEMORY_HOTPLUG is enabled, because cpu_up() will call
cpu_to_node() before per_cpu(numa_node) is setup for APs.

When Node0 doesn't have RAM, on x86, cpus already round it to nearest
node with RAM in x86_cpu_to_node_map.  and per_cpu(numa_node) is not set
up until in c_init for APs.

When later cpu_up() calling cpu_to_node() will get 0 again, and make it
online even there is no RAM on node0.  so later all APs can not booted up,
and later will have panic.

[    1.611101] On node 0 totalpages: 0
.........
[    2.608558] On node 0 totalpages: 0
[    2.612065] Brought up 1 CPUs
[    2.615199] Total of 1 processors activated (3990.31 BogoMIPS).
...
   93.225341] calling  loop_init+0x0/0x1a4 @ 1
[   93.229314] PERCPU: allocation failed, size=80 align=8, failed to populate
[   93.246539] Pid: 1, comm: swapper Tainted: G        W   2.6.35-rc4-tip-yh-04371-gd64e6c4-dirty #354
[   93.264621] Call Trace:
[   93.266533]  [<ffffffff81125e43>] pcpu_alloc+0x83a/0x8e7
[   93.270710]  [<ffffffff81125f15>] __alloc_percpu+0x10/0x12
[   93.285849]  [<ffffffff8140786c>] alloc_disk_node+0x94/0x16d
[   93.291811]  [<ffffffff81407956>] alloc_disk+0x11/0x13
[   93.306157]  [<ffffffff81503e51>] loop_alloc+0xa7/0x180
[   93.310538]  [<ffffffff8277ef48>] loop_init+0x9b/0x1a4
[   93.324909]  [<ffffffff8277eead>] ? loop_init+0x0/0x1a4
[   93.329650]  [<ffffffff810001f2>] do_one_initcall+0x57/0x136
[   93.345197]  [<ffffffff827486d0>] kernel_init+0x184/0x20e
[   93.348146]  [<ffffffff81034954>] kernel_thread_helper+0x4/0x10
[   93.365194]  [<ffffffff81c7cc3c>] ? restore_args+0x0/0x30
[   93.369305]  [<ffffffff8274854c>] ? kernel_init+0x0/0x20e
[   93.386011]  [<ffffffff81034950>] ? kernel_thread_helper+0x0/0x10
[   93.392047] loop: out of memory
...

Try to assign per_cpu(numa_node) early

[akpm@linux-foundation.org: tidy up code comment]
Signed-off-by: NYinghai <yinghai@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Acked-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In commit f007ea26, the order of the %es and %ds segment registers
got accidentally swapped, so synthesized 'struct pt_regs' frames
have the two values inverted.  It's almost sure that these values
never matter, and that they also never differ.  But wrong is wrong.
Signed-off-by: NRoland McGrath <roland@redhat.com>

Found one x2apic system kexec loop test failed
when CONFIG_NMI_WATCHDOG=y (old) or CONFIG_LOCKUP_DETECTOR=y (current tip)

first kernel can kexec second kernel, but second kernel can not kexec third one.

it can be duplicated on another system with BIOS preenabled x2apic.
First kernel can not kexec second kernel.

It turns out, when kernel boot with pre-enabled x2apic, it will not execute
disable_local_APIC on shutdown path.

when init_apic_mappings() is called in setup_arch, it will skip setting of
apic_phys when x2apic_mode is set. ( x2apic_mode is much early check_x2apic())
Then later, disable_local_APIC() will bail out early because !apic_phys.

So check !x2apic_mode in x2apic_mode in disable_local_APIC with !apic_phys.

another solution could be updating init_apic_mappings() to set apic_phys even
for preenabled x2apic system. Actually even for x2apic system, that lapic
address is mapped already in early stage.

BTW: is there any x2apic preenabled system with apicid of boot cpu > 255?
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
LKML-Reference: <4C3EB22B.3000701@kernel.org>
Acked-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: stable@kernel.org
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

commit 30a564be (x86, hpet: Restrict read back to affected ATI
chipset) restricted the workaround for the HPET bug to SMX00
chipsets. This was reasonable as those were the only ones against
which we ever got a bug report.

Stephan Wolf reported now that this patch breaks his IXP400 based
machine. Though it's confirmed to work on other IXP400 based systems.

To error out on the safe side, we force the HPET readback workaround
for all ATI SMbus class chipsets.
Reported-by: NStephan Wolf <stephan@letzte-bankreihe.de>
LKML-Reference: <alpine.LFD.2.00.1007142134140.3321@localhost.localdomain>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: NStephan Wolf <stephan@letzte-bankreihe.de>
Acked-by: NBorislav Petkov <borislav.petkov@amd.com>

It will just return 0 as there is no i8042 controller
Signed-off-by: NFeng Tang <feng.tang@intel.com>
LKML-Reference: <1278342202-10973-3-git-send-email-feng.tang@intel.com>
Acked-by: NDmitry Torokhov <dtor@mail.ru>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Some x86 platforms like Intel MID platforms don't have i8042 controllers,
and i8042 driver's probe to some legacy IO ports may hang the MID
processor. With this hook, i8042 driver can runtime check and skip the
probe when the pretection fail which also saves some probe time

[ hpa note: this is currently a compile-time check, which breaks the
  i386 allyesconfig build.  This patch series thus does fix a regression. ]
Signed-off-by: NFeng Tang <feng.tang@intel.com>
LKML-Reference: <1278342202-10973-2-git-send-email-feng.tang@intel.com>
Acked-by: NDmitry Torokhov <dtor@mail.ru>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Export x86_platform to modules in preparation of using it for i8042
discovery control.
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
LKML-Reference: <1278342202-10973-1-git-send-email-feng.tang@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Dmitry Torokhov <dtor@mail.ru>

While doing some performance counter validation tests on some
assembly language programs I noticed that the "branches:u"
count was very wrong on AMD machines.

It looks like the wrong event was selected.
Signed-off-by: NVince Weaver <vweaver1@eecs.utk.edu>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Borislav Petkov <borislav.petkov@amd.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: <stable@kernel.org>
LKML-Reference: <alpine.DEB.2.00.1007011526010.23160@cl320.eecs.utk.edu>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The x3950 family can have as many as 256 PCI buses in a single system, so
change the limits to the maximum.  Since there can only be 256 PCI buses in one
domain, we no longer need the BUG_ON check.
Signed-off-by: NDarrick J. Wong <djwong@us.ibm.com>
LKML-Reference: <20100701004519.GQ15515@tux1.beaverton.ibm.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Before we had a generic breakpoint layer, x86 used to send a
sigtrap for any debug event that happened in userspace,
except if it was caused by lazy dr7 switches.

Currently we only send such signal for single step or breakpoint
events.

However, there are three other kind of debug exceptions:

- debug register access detected: trigger an exception if the
  next instruction touches the debug registers. We don't use
  it.
- task switch, but we don't use tss.
- icebp/int01 trap. This instruction (0xf1) is undocumented and
  generates an int 1 exception. Unlike single step through TF
  flag, it doesn't set the single step origin of the exception
  in dr6.

icebp then used to be reported in userspace using trap signals
but this have been incidentally broken with the new breakpoint
code. Reenable this. Since this is the only debug event that
doesn't set anything in dr6, this is all we have to check.

This fixes a regression in Wine where World Of Warcraft got broken
as it uses this for software protection checks purposes. And
probably other apps do.
Reported-and-tested-by: NAlexandre Julliard <julliard@winehq.org>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: 2.6.33.x 2.6.34.x <stable@kernel.org>

Newer systems (x3950M2) can have 48 PHBs per chassis and 8
chassis, so bump the limits up and provide an explanation
of the requirements for each class.
Signed-off-by: NDarrick J. Wong <djwong@us.ibm.com>
Acked-by: NMuli Ben-Yehuda <muli@il.ibm.com>
Cc: Corinna Schultz <cschultz@linux.vnet.ibm.com>
Cc: <stable@kernel.org>
LKML-Reference: <20100624212647.GI15515@tux1.beaverton.ibm.com>
[ v2: Fixed build bug, added back PHBS_PER_CALGARY == 4 ]
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Dell Precision WorkStation T7400 freezes on reboot unless
reboot=b is used.

Reference: https://qa.mandriva.com/show_bug.cgi?id=58017Signed-off-by: NThomas Backlund <tmb@mandriva.org>
LKML-Reference: <4C1CC6E9.6000701@mandriva.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Saving platform non-volatile state may be required for suspend to RAM as
well as hibernation. Move it to more generic code.
Signed-off-by: NMatthew Garrett <mjg@redhat.com>
Acked-by: NRafael J. Wysocki <rjw@sisk.pl>
Tested-by: NMaxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

Based on Intel Vol3b (March 2010), the event
SNOOPQ_REQUEST_OUTSTANDING is restricted to counters 0,1 so
update the event table for Intel Westmere accordingly.
Signed-off-by: NStephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: paulus@samba.org
Cc: davem@davemloft.net
Cc: fweisbec@gmail.com
Cc: perfmon2-devel@lists.sf.net
Cc: eranian@gmail.com
Cc: <stable@kernel.org> # .34.x
LKML-Reference: <4c10cb56.5120e30a.2eb4.ffffc3de@mx.google.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

When I introduced the global variable gsi_end I thought gsi_end on
io_apics was one past the end of the gsi range for the io_apic.  After
it was pointed out the the range on io_apics was inclusive I changed
my global variable to match.  That was a big mistake.  Inclusive
semantics without a range start cannot describe the case when no gsi's
are allocated.  Describing the case where no gsi's are allocated is
important in sfi.c and mpparse.c so that we can assign gsi numbers
instead of blindly copying the gsi assignments the BIOS has done as we
do in the acpi case.

To keep from getting the global variable confused with the gsi range
end rename it gsi_top.

To allow describing the case where no gsi's are allocated have gsi_top
be one place the highest gsi number seen in the system.

This fixes an off by one bug in sfi.c:
Reported-by: Njacob pan <jacob.jun.pan@linux.intel.com>

This fixes the same off by one bug in mpparse.c:

This fixes an off unreachable by one bug in acpi/boot.c:irq_to_gsi
Reported-by: NYinghai <yinghai.lu@oracle.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
LKML-Reference: <m17hm9jre7.fsf_-_@fess.ebiederm.org>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Percpu initialization happens now after booting the cores on the
machine and this causes them all to be displayed as belonging to
node 0:

Jun  8 05:57:21 kepek kernel: [    0.106999] Booting Node   0,
Processors  #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14 #15 #16 #17 #18 #19 #20 #21 #22 #23 Ok.

Use early_cpu_to_node() to get the correct node of each core
instead.
Signed-off-by: NBorislav Petkov <borislav.petkov@amd.com>
Cc: Mike Travis <travis@sgi.com>
LKML-Reference: <20100601190455.GA14237@aftab>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This patch implements a fallback to the GART IOMMU if this
is possible and the AMD IOMMU initialization failed.
Otherwise the fallback would be nommu which is very
problematic on machines with more than 4GB of memory or
swiotlb which hurts io-performance.

Cc: stable@kernel.org
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

When request_mem_region fails the error path tries to
disable the IOMMUs. This accesses the mmio-region which was
not allocated leading to a kernel crash. This patch fixes
the issue.

Cc: stable@kernel.org
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

DBG() macro for CONFIG_DEBUG_PER_CPU_MAPS is unused.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
LKML-Reference: <1274706291-13554-1-git-send-email-akinobu.mita@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The transactional API patch between the generic and model-specific
code introduced several important bugs with event scheduling, at
least on X86. If you had pinned events, e.g., watchdog,  and were
over-committing the PMU, you would get bogus counts. The bug was
showing up on Intel CPU because events would move around more
often that on AMD. But the problem also existed on AMD, though
harder to expose.

The issues were:

 - group_sched_in() was missing a cancel_txn() in the error path

 - cpuc->n_added was not properly maintained, leading to missing
   actions in hw_perf_enable(), i.e., n_running being 0. You cannot
   update n_added until you know the transaction has succeeded. In
   case of failed transaction n_added was not adjusted back.

 - in case of failed transactions, event_sched_out() was called
   and eventually invoked x86_disable_event() to touch the HW reg.
   But with transactions, on X86, event_sched_in() does not touch
   HW registers, it simply collects events into a list. Thus, you
   could end up calling x86_disable_event() on a counter which
   did not correspond to the current event when idx != -1.

The patch modifies the generic and X86 code to avoid all those problems.

First, we keep track of the number of events added last. In case the
transaction fails, we substract them from n_added. This approach is
necessary (as opposed to delaying updates to n_added) because not all
event updates use the transaction API, e.g., single events.

Second, we encapsulate the event_sched_in() and event_sched_out() in
group_sched_in() inside the transaction. That makes the operations
symmetrical and you can also detect that you are inside a transaction
and skip the HW reg access by checking cpuc->group_flag.

With this patch, you can now overcommit the PMU even with pinned
system-wide events present and still get valid counts.
Signed-off-by: NStephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1274796225.5882.1389.camel@twins>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

x86 arch specific changes to use generic numa_node_id() based on generic
percpu variable infrastructure.  Back out x86's custom version of
numa_node_id()
Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Eric Whitney <eric.whitney@hp.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

sync_single_range_for_cpu and sync_single_range_for_device hooks in
swiotlb_dma_ops are unnecessary because sync_single_for_cpu and
sync_single_for_device are used there.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

By the previous modification, the cpu notifier can return encapsulate
errno value.  This converts the cpu notifiers for msr, cpuid, and
therm_throt.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add a spin_unlock missing on the error path.  The locks and unlocks are
balanced in other functions, so it seems that the same should be the case
here.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression E1;
@@

* spin_lock(E1,...);
  <+... when != E1
  if (...) {
    ... when != E1
*   return ...;
  }
  ...+>
* spin_unlock(E1,...);
// </smpl>

Cc: stable@kernel.org
Signed-off-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

Fix the following warning:

"WARNING: arch/x86/kernel/built-in.o(.exit.text+0x72):
Section mismatch in reference from the function powernowk8_exit() to the variable .cpuinit.data:cpb_nb

The function __exit powernowk8_exit() references a variable
__cpuinitdata cpb_nb. This is often seen when error handling in the exit
function uses functionality in the init path. The fix is often to remove
the __cpuinitdata annotation of cpb_nb so it may be used outside an init
section."

Cc: <stable@kernel.org>
Reported-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NBorislav Petkov <borislav.petkov@amd.com>
LKML-Reference: <20100525152858.GA24836@aftab>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

This adds:
  alias: devname:<name>
to some common kernel modules, which will allow the on-demand loading
of the kernel module when the device node is accessed.

Ideally all these modules would be compiled-in, but distros seems too
much in love with their modularization that we need to cover the common
cases with this new facility. It will allow us to remove a bunch of pretty
useless init scripts and modprobes from init scripts.

The static device node aliases will be carried in the module itself. The
program depmod will extract this information to a file in the module directory:
  $ cat /lib/modules/2.6.34-00650-g537b60d1-dirty/modules.devname
  # Device nodes to trigger on-demand module loading.
  microcode cpu/microcode c10:184
  fuse fuse c10:229
  ppp_generic ppp c108:0
  tun net/tun c10:200
  dm_mod mapper/control c10:235

Udev will pick up the depmod created file on startup and create all the
static device nodes which the kernel modules specify, so that these modules
get automatically loaded when the device node is accessed:
  $ /sbin/udevd --debug
  ...
  static_dev_create_from_modules: mknod '/dev/cpu/microcode' c10:184
  static_dev_create_from_modules: mknod '/dev/fuse' c10:229
  static_dev_create_from_modules: mknod '/dev/ppp' c108:0
  static_dev_create_from_modules: mknod '/dev/net/tun' c10:200
  static_dev_create_from_modules: mknod '/dev/mapper/control' c10:235
  udev_rules_apply_static_dev_perms: chmod '/dev/net/tun' 0666
  udev_rules_apply_static_dev_perms: chmod '/dev/fuse' 0666

A few device nodes are switched to statically allocated numbers, to allow
the static nodes to work. This might also useful for systems which still run
a plain static /dev, which is completely unsafe to use with any dynamic minor
numbers.

Note:
The devname aliases must be limited to the *common* and *single*instance*
device nodes, like the misc devices, and never be used for conceptually limited
systems like the loop devices, which should rather get fixed properly and get a
control node for losetup to talk to, instead of creating a random number of
device nodes in advance, regardless if they are ever used.

This facility is to hide the mess distros are creating with too modualized
kernels, and just to hide that these modules are not compiled-in, and not to
paper-over broken concepts. Thanks! :)

Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Alasdair G Kergon <agk@redhat.com>
Cc: Tigran Aivazian <tigran@aivazian.fsnet.co.uk>
Cc: Ian Kent <raven@themaw.net>
Signed-Off-By: NKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Patch b7e2ecef (perf, trace: Optimize tracepoints by removing
IRQ-disable from perf/tracepoint interaction) made the
unfortunate mistake of assuming the world is x86 only, correct
this.

The problem was that perf_fetch_caller_regs() did
local_save_flags() into regs->flags, and I re-used that to
remove another local_save_flags(), forgetting !x86 doesn't have
regs->flags.

Do the reverse, remove the local_save_flags() from
perf_fetch_caller_regs() and let the ftrace site do the
local_save_flags() instead.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: NPaul Mackerras <paulus@samba.org>
Cc: acme@redhat.com
Cc: efault@gmx.de
Cc: fweisbec@gmail.com
Cc: rostedt@goodmis.org
LKML-Reference: <1274778175.5882.623.camel@twins>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The low-memory corruption checker triggers during suspend/resume, so we
need to reserve the low 64k.  Don't be fooled that the BIOS identifies
itself as "Dell Inc.", it's still Phoenix BIOS.

[ hpa: I think we blacklist almost every BIOS in existence.  We should
either change this to a whitelist or just make it unconditional. ]
Signed-off-by: NGabor Gombas <gombasg@digikabel.hu>
LKML-Reference: <201005241913.o4OJDIMM010877@imap1.linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
Cc: <stable@kernel.org>

Bits set in cpu_possible_mask prior to the execution of
prefill_possible_map() (i.e.  when parsing ACPI or MPS tables) would
prevent the SMP alternatives logic from switching to UP mode, plus
unnecessary setup of per-CPU data for CPUs that can never come online.

Additionally, without CONFIG_HOTPLUG_CPU disabled CPUs can never come
online, and hence setting cpu_possible_mask bits for them is again a
simple waste of resources.
Signed-off-by: NJan Beulich <jbeulich@novell.com>
LKML-Reference: <201005241913.o4OJDH3Z010874@imap1.linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

When the SMP kernel decides to crash_kexec() the local APICs may have
pending interrupts in their vector tables.

The setup routine for the local APIC has a deficient mechanism for
clearing these interrupts, it only handles interrupts that has already
been dispatched to the local core for servicing (the ISR register) safely,
it doesn't consider lower prioritized queued interrupts stored in the IRR
register.

If you have more than one pending interrupt within the same 32 bit word in
the LAPIC vector table registers you may find yourself entering the IO
APIC setup with pending interrupts left in the LAPIC.  This is a situation
for wich the IO APIC setup is not prepared.  Depending of what/which
interrupt vector/vectors are stuck in the APIC tables your system may show
various degrees of malfunctioning.  That was the reason why the
check_timer() failed in our system, the timer interrupts was blocked by
pending interrupts from the old kernel when routed trough the IO APIC.

Additional comment from Jiri Bohac:
==============
If this should go into stable release,
I'd add some kind of limit on the number of iterations, just to be safe from
hard to debug lock-ups:

+if (loops++  > MAX_LOOPS) {
+        printk("LAPIC pending clean-up")
+        break;
+}
 while (queued);

with MAX_LOOPS something like 1E9 this would leave plenty of time for the
pending IRQs to be cleared and would and still cause at most a second of delay
if the loop were to lock-up for whatever reason.

[trenn@suse.de:

V2: Use tsc if avail to bail out after 1 sec due to possible virtual
    apic_read calls which may take rather long (suggested by: Avi Kivity
    <avi@redhat.com>) If no tsc is available bail out quickly after
    cpu_khz, if we broke out too early and still have irqs pending (which
    should never happen?) we still get a WARN_ON...

V3: - Fixed indentation -> checkpatch clean
    - max_loops must be signed

V4: - Fix typo, mixed up tsc and ntsc in first rdtscll() call

V5: Adjust WARN_ON() condition to also catch error in cpu_has_tsc case]

Cc: <jbohac@novell.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Kerstin Jonsson <kerstin.jonsson@ericsson.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Tested-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NThomas Renninger <trenn@suse.de>
LKML-Reference: <201005241913.o4OJDGWM010865@imap1.linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Allow kdb to work properly with with earlyprintk=vga by interpreting
the backspace and carriage return output characters.  These
interpretation of these characters is used for simple line editing
provided in the kdb shell.

CC: Thomas Gleixner <tglx@linutronix.de>
CC: Ingo Molnar <mingo@redhat.com>
CC: H. Peter Anvin <hpa@zytor.com>
CC: x86@kernel.org
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>

If the kernel debugger was configured, attached and started with
kgdbwait, the hardware breakpoint registers should get restored by the
kgdb code which is managing the dr registers.

CC: x86@kernel.org
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Ingo Molnar <mingo@redhat.com>
CC: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>

It is not possible to use the hw_breakpoint.c API prior to mm_init(),
but it is possible to use hardware breakpoints with the kernel
debugger.

Prior to smp_init() it is possible to simply write to the dr registers
of the boot cpu directly.  This can be used up until the
kgdb_arch_late() is invoked, at which point the standard hw_breakpoint.c
API will get used.

CC: Frederic Weisbecker <fweisbec@gmail.com>
CC: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>

The kernel debugger can operate well before mm_init(), but the x86
hardware breakpoint code which uses the perf api requires that the
kernel allocators are initialized.

This means the kernel debug core needs to provide an optional arch
specific call back to allow the initialization functions to run after
the kernel has been further initialized.

The kdb shell already had a similar restriction with an early
initialization and late initialization.  The kdb_init() was moved into
the debug core's version of the late init which is called
dbg_late_init();

CC: kgdb-bugreport@lists.sourceforge.net
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>

Allow the x86 arch to have early exception processing for the purpose
of debugging via the kgdb.
Signed-off-by: NJan Kiszka <jan.kiszka@web.de>
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>

The only way the debugger can handle a trap in inside rcu_lock,
notify_die, or atomic_notifier_call_chain without a triple fault is
to have a low level "first opportunity handler" in the int3 exception
handler.

Generally this will be something the vast majority of folks will not
need, but for those who need it, it is added as a kernel .config
option called KGDB_LOW_LEVEL_TRAP.

CC: Ingo Molnar <mingo@elte.hu>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: H. Peter Anvin <hpa@zytor.com>
CC: x86@kernel.org
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>

Remove all the references to the kgdb_post_primary_code.  This
function serves no useful purpose because you can obtain the same
information from the "struct kgdb_state *ks" from with in the
debugger, if for some reason you want the data.

Also remove the unintentional duplicate assignment for ks->ex_vector.
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>

These are the minimum changes to the kgdb core in order to enable an
API to connect a new front end (kdb) to the debug core.

This patch introduces the dbg_kdb_mode variable controls where the
user level I/O is routed.  It will be routed to the gdbstub (kgdb) or
to the kdb front end which is a simple shell available over the kgdboc
connection.

You can switch back and forth between kdb or the gdb stub mode of
operation dynamically.  From gdb stub mode you can blindly type
"$3#33", or from the kdb mode you can enter "kgdb" to switch to the
gdb stub.

The logic in the debug core depends on kdb to look for the typical gdb
connection sequences and return immediately with KGDB_PASS_EVENT if a
gdb serial command sequence is detected.  That should allow a
reasonably seamless transition between kdb -> gdb without leaving the
kernel exception state.  The two gdb serial queries that kdb is
responsible for detecting are the "?" and "qSupported" packets.

CC: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>
Acked-by: NMartin Hicks <mort@sgi.com>