Lockdep reports the warning below when Li tries to offline one cpu:

[  110.835487] =================================
[  110.835616] [ INFO: inconsistent lock state ]
[  110.835688] 2.6.30-rc4-00336-g8c9ed899 #52
[  110.835757] ---------------------------------
[  110.835828] inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage.
[  110.835908] swapper/0 [HC1[1]:SC0[0]:HE0:SE1] takes:
[  110.835982]  (cmci_discover_lock){?.+...}, at: [<ffffffff80236dc0>] cmci_clear+0x30/0x9b

cmci_clear() can be called via smp_call_function_single().

It is better to disable interrupt while holding cmci_discover_lock,
to turn it into an irq-safe lock - we can deadlock otherwise.

[ Impact: fix possible deadlock in the MCE code ]
Reported-by: NShaohua Li <shaohua.li@intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <4A03ED38.8000700@jp.fujitsu.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Reported-by: Shaohua Li<shaohua.li@intel.com>

Tim Starling reported that crashdump will panic with kernel compiled
with CONFIG_KEXEC_JUMP due to null pointer deference in
machine_kexec_32.c: machine_kexec(), when deferencing
kexec_image. Refering to:

http://bugzilla.kernel.org/show_bug.cgi?id=13265

This patch fixes the BUG via replacing global variable reference:
kexec_image in machine_kexec() with local variable reference: image,
which is more appropriate, and will not be null.

Same BUG is in machine_kexec_64.c too, so fixed too in the same way.

[ Impact: fix crash on kexec ]
Reported-by: NTim Starling <tstarling@wikimedia.org>
Signed-off-by: NHuang Ying <ying.huang@intel.com>
LKML-Reference: <1241751101.6259.85.camel@yhuang-dev.sh.intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

If the first non-reserved (sub-)range doesn't fit the size requested,
an endless loop will be entered. If a range returned from
find_e820_area_size() turns out insufficient in size, the range must
be skipped before calling the function again.

[ Impact: fixes boot hang on some platforms ]
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Commit 7ad728f9
(cpumask: x86: convert cpu_sibling_map/cpu_core_map to cpumask_var_t)
changed the output of /proc/cpuinfo for siblings:

Example on an AMD Phenom:

  physical id   : 0
  siblings : 1
  core id	   : 3
  cpu cores  : 4

Before that commit it was:

  physical id	: 0
  siblings : 4
  core id	   : 3
  cpu cores  : 4

Instead of cpu_core_mask it now uses cpu_sibling_mask to count siblings.
This is due to the following hunk of above commit:

|  --- a/arch/x86/kernel/cpu/proc.c
|  +++ b/arch/x86/kernel/cpu/proc.c
|  @@ -14,7 +14,7 @@ static void show_cpuinfo_core(struct seq_file *m, struct cpuinf
|          if (c->x86_max_cores * smp_num_siblings > 1) {
|                  seq_printf(m, "physical id\t: %d\n", c->phys_proc_id);
|                  seq_printf(m, "siblings\t: %d\n",
|  -                          cpus_weight(per_cpu(cpu_core_map, cpu)));
|  +                          cpumask_weight(cpu_sibling_mask(cpu)));
|                  seq_printf(m, "core id\t\t: %d\n", c->cpu_core_id);
|                  seq_printf(m, "cpu cores\t: %d\n", c->booted_cores);
|                  seq_printf(m, "apicid\t\t: %d\n", c->apicid);

This was a mistake, because the impact line shows that this side-effect
was not anticipated:

   Impact: reduce per-cpu size for CONFIG_CPUMASK_OFFSTACK=y

So revert the respective hunk to restore the old behavior.

[ Impact: fix sibling-info regression in /proc/cpuinfo ]
Signed-off-by: NAndreas Herrmann <andreas.herrmann3@amd.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
LKML-Reference: <20090504182859.GA29045@alberich.amd.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The feature bits should be set via bitmasks, not via feature IDs.

[ Impact: fix feature enabling in newer IOMMU versions ]
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>
LKML-Reference: <20090504102028.GA30307@amd.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

commit db949bba (x86-32: use non-lazy
io bitmap context switching) broke ioperm for 32bit because it removed
the lazy initialization of io_bitmap_base and did not set it to the
real bitmap offset.

[ Impact: fix non-working sys_ioperm() on 32-bit kernels ]
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

The HPET in the ICH4M is not documented in the data sheet
because it was not officially validated.

While it is fine for hackers to continue to use "hpet=force"
to enable the hardware that they have, it is not prudent to
solicit additional "hpet=force" users on this hardware.

[ Impact: remove hpet=force syslog message on old-ICH systems ]
Signed-off-by: NLen Brown <len.brown@intel.com>
Acked-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
LKML-Reference: <alpine.LFD.2.00.0904231918510.15843@localhost.localdomain>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The earlier patch to change the poller to a separate function subtly
broke the boot logging logic. This could lead to machine checks
getting logged at boot even when disabled or defaulting to off
on some systems. Fix that.

[ Impact: bug fix - avoid spurious MCE in log ]
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Reviewed-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

The polling timer while running per CPU still uses a global next_interval
variable, which lead to some CPUs either polling too fast or too slow.   
This was not a serious problem because all errors get picked up eventually,
but it's still better to avoid it. Turn next_interval into a per cpu variable.

v2: Fix check_interval == 0 case (Hidetoshi Seto)

[ Impact: minor bug fix ]
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Reviewed-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

uv_read_rtc() is referenced by read member of struct clocksource clocksource_uv.
In include/linux/clocksource.h, read of struct clocksource is declared as:
cycle_t (*read)(struct clocksource *cs)

This got introduced recently in:

   8e19608e: clocksource: pass clocksource to read() callback

But arch/x86/kernel/uv_time.c was not properly converted by that pach.

This patch adds a dummy parameter (struct clocksource type) to uv_read_rtc() to
fix the incompatible reference in clocksource_uv, and add a NULL parameter in
all places where uv_read_rtc() gets called.

[ Impact: cleanup, address compiler warning ]
Signed-off-by: NColy Li <coly.li@suse.de>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Cc: Magnus Damm <damm@igel.co.jp>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hugh@veritas.com>
LKML-Reference: <49EF3614.1050806@suse.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Cc: Dimitri Sivanich <sivanich@sgi.com>

(See http://bugzilla.kernel.org/show_bug.cgi?id=12961)

It partially reverts commit c23e253e
(x86: hpet: stop HPET_COUNTER when programming periodic mode)

HPET on AMD 81xx chipset needs a second write (with HPET_TN_SETVAL
cleared) to T0_CMP register to set the period in periodic mode.

With this patch HPET_COUNTER is still stopped but not reset when HPET
is programmed in periodic mode. This should help to avoid races when
HPET is programmed in periodic mode and fixes a boot time hang that
I've observed on a machine when using 1000HZ.

[ Impact: fix boot time hang on machines with AMD 81xx chipset ]
Reported-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NAndreas Herrmann <andreas.herrmann3@amd.com>
Tested-by: NJeff Mahoney <jeffm@suse.com>
LKML-Reference: <20090421180037.GA2763@alberich.amd.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Pass clocksource pointer to the read() callback for clocksources.  This
allows us to share the callback between multiple instances.

[hugh@veritas.com: fix powerpc build of clocksource pass clocksource mods]
[akpm@linux-foundation.org: cleanup]
Signed-off-by: NMagnus Damm <damm@igel.co.jp>
Acked-by: NJohn Stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In theory (though not shown in practice) alloc_cpumask_var() doesn't zero
memory, so CPUs might print an "NMI backtrace for cpu %d" once on boot.

(Bug introduced in fcef8576).

[ Impact: avoid theoretical syslog noise in rare configs ]
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <alpine.DEB.2.00.0904202113520.10097@gandalf.stny.rr.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

fcef8576 converted backtrace_mask to a
cpumask_var_t, and assumed check_nmi_watchdog was called before
nmi_watchdog_tick was ever called.  Steven's oops shows I was wrong.

This is something of a bandaid: I'm not sure we *should* be calling
nmi_watchdog_tick before check_nmi_watchdog.  Note that gcc eliminates
this test for the CONFIG_CPUMASK_OFFSTACK=n case.

[ Impact: fix boot crash in rare configs ]
Reported-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
LKML-Reference: <alpine.DEB.2.00.0904202113520.10097@gandalf.stny.rr.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

In 64bit signal delivery path, clear_used_math() was happening before saving
the current active FPU state on to the user stack for signal handling. Between
clear_used_math() and the state store on to the user stack, potentially we
can get a page fault for the user address and can block. Infact, while testing
we were hitting the might_fault() in __clear_user() which can do a schedule().

At a later point in time, we will schedule back into this process and
resume the save state (using "xsave/fxsave" instruction) which can lead
to DNA fault. And as used_math was cleared before, we will reinit the FP state
in the DNA fault and continue. This reinit will result in loosing the
FPU state of the process.

Move clear_used_math() to a point after the FPU state has been stored
onto the user stack.

This issue is present from a long time (even before the xsave changes
and the x86 merge). But it can easily be exposed in 2.6.28.x and 2.6.29.x
series because of the __clear_user() in this path, which has an explicit
__cond_resched() leading to a context switch with CONFIG_PREEMPT_VOLUNTARY.

[ Impact: fix FPU state corruption ]
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: <stable@kernel.org>			[2.6.28.x, 2.6.29.x]
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Fix endcase where the memory at physical address 0 does not really
exist AND one of the sockets on blade 0 has no active cpus.

The memory that _appears_ to be at physical address 0 is actually
memory that located at a different address but has been remapped by
the chipset so that it appears to be at physical address 0.

When determining the UV pnode, the algorithm for determining the pnode
incorrectly used the relocated physical address instead of the actual
(global) address.

[ Impact: boot failure on partitioned systems ]
Signed-off-by: NJack Steiner <steiner@sgi.com>
LKML-Reference: <20090420132530.GA23156@sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Take already available policy->cpuinfo.max_freq and get rid of acpi-cpufreq
specific max_freq variable.

This implies that P0 is always the highest frequency which should always
be true as ACPI spec says:
As a result, the zeroth entry describes the highest performance state
Signed-off-by: NThomas Renninger <trenn@suse.de>
Acked-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

Signed-off-by: NThomas Renninger <trenn@suse.de>
Signed-off-by: NLen Brown <len.brown@intel.com>

Signed-off-by: NThomas Renninger <trenn@suse.de>
Signed-off-by: NLen Brown <len.brown@intel.com>

Fix for a regression that was introduced by earlier commit
18b2646f on Mon Apr 6 11:26:08 2009

Regression resulted in the below error happened on systems with
software coordination where per_cpu acpi data will not be initiated for
secondary CPUs in a P-state domain.

On Tue, 2009-04-14 at 23:01 -0700, Zhang, Yanmin wrote:
 My machine hanged with kernel 2.6.30-rc2 when script read
> /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor.
>
> opps happens in get_measured_perf:
>
>         cur.aperf.whole = readin.aperf.whole -
>                                 per_cpu(drv_data, cpu)->saved_aperf;
>
> Because per_cpu(drv_data, cpu)=NULL.
>
> So function get_measured_perf should check if (per_cpu(drv_data,
> cpu)==NULL)
> and return 0 if it's NULL.

--------------sys log------------------

BUG: unable to handle kernel NULL pointer dereference at
0000000000000020
IP: [<ffffffff8021af75>] get_measured_perf+0x4a/0xf9
PGD a7dd88067 PUD a7ccf5067 PMD 0
Oops: 0000 [#1] SMP
last sysfs file: /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
CPU 0
Modules linked in: video output
Pid: 2091, comm: kondemand/0 Not tainted 2.6.30-rc2 #1 MP Server
RIP: 0010:[<ffffffff8021af75>]  [<ffffffff8021af75>]
get_measured_perf+0x4a/0xf9
RSP: 0018:ffff880a7d56de20  EFLAGS: 00010246
RAX: 0000000000000000 RBX: 00000046241a42b6 RCX: ffff88004d219000
RDX: 000000000000b660 RSI: 0000000000000020 RDI: 0000000000000001
RBP: ffff880a7f052000 R08: 00000046241a42b6 R09: ffffffff807639f0
R10: 00000000ffffffea R11: ffffffff802207f4 R12: ffff880a7f052000
R13: ffff88004d20e460 R14: 0000000000ddd5a6 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff88004d200000(0000)
knlGS:0000000000000000
CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
CR2: 0000000000000020 CR3: 0000000a7f1bf000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process kondemand/0 (pid: 2091, threadinfo ffff880a7d56c000, task
ffff880a7d4d18c0)
Stack:
 ffff880a7f052078 ffffffff803efd54 00000046241a42b6 000000462ffa9e95
 0000000000000001 0000000000000001 00000000ffffffea ffffffff8064f41a
 0000000000000012 0000000000000012 ffff880a7f052000 ffffffff80650547
Call Trace:
 [<ffffffff803efd54>] ? kobject_get+0x12/0x17
 [<ffffffff8064f41a>] ? __cpufreq_driver_getavg+0x42/0x57
 [<ffffffff80650547>] ? do_dbs_timer+0x147/0x272
 [<ffffffff80650400>] ? do_dbs_timer+0x0/0x272
 [<ffffffff802474ca>] ? worker_thread+0x15b/0x1f5
 [<ffffffff8024a02c>] ? autoremove_wake_function+0x0/0x2e
 [<ffffffff8024736f>] ? worker_thread+0x0/0x1f5
 [<ffffffff80249f0d>] ? kthread+0x54/0x83
 [<ffffffff8020c87a>] ? child_rip+0xa/0x20
 [<ffffffff80249eb9>] ? kthread+0x0/0x83
 [<ffffffff8020c870>] ? child_rip+0x0/0x20
Code: 99 a6 03 00 31 c9 85 c0 0f 85 c3 00 00 00 89 df 4c 8b 44 24 10 48
c7 c2 60 b6 00 00 48 8b 0c fd e0 30 a5 80 4c 89 c3 48 8b 04 0a <48> 2b
58 20 48 8b 44 24 18 48 89 1c 24 48 8b 34 0a 48 2b 46 28
RIP  [<ffffffff8021af75>] get_measured_perf+0x4a/0xf9
 RSP <ffff880a7d56de20>
CR2: 0000000000000020
---[ end trace 2b8fac9a49e19ad4 ]---
Tested-by: N"Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

I hit the check_flags error of lockdep:

 WARNING: at kernel/lockdep.c:2893 check_flags+0x1a7/0x1d0()
 [...]
 hardirqs last  enabled at (12567): [<ffffffff8026206a>] local_bh_enable+0xaa/0x110
 hardirqs last disabled at (12569): [<ffffffff80610c76>] int3+0x16/0x40
 softirqs last  enabled at (12566): [<ffffffff80514d2b>] lock_sock_nested+0xfb/0x110
 softirqs last disabled at (12568): [<ffffffff8058454e>] tcp_prequeue_process+0x2e/0xa0

The check_flags warning of lockdep tells me that lockdep thought interrupts
were disabled, but they were really enabled.

The numbers in the above parenthesis show the order of events:

 12566: softirqs last enabled:  lock_sock_nested
 12567: hardirqs last enabled:  local_bh_enable
 12568: softirqs last disabled: tcp_prequeue_process
 12566: hardirqs last disabled: int3

int3 is a breakpoint!

Examining this further, I have CONFIG_NET_TCPPROBE enabled which adds
break points into the kernel.

The paranoid_exit of the return of int3 does not account for enabling
interrupts on return to kernel. This code is a bit tricky since it
is also used by the nmi handler (when lockdep is off), and we must be
careful about the swapgs. We can not call kernel code after the swapgs
has been performed.

[ Impact: fix lockdep check_flags warning + self-turn-off ]
Acked-by: NPeter Zijlsta <a.p.zijlstra@chello.nl>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Fix an endcase in the UV initialization code for the "UV large system mode"
of apicids.  If node zero contains no cpus, cpus on another node will be the
boot cpu.  The percpu data that contains the extra apicid bits was not
being initialized early enough.

[ Impact: fix potential boot crash on cpu-less UV nodes ]
Signed-off-by: NJack Steiner <steiner@sgi.com>
LKML-Reference: <20090417142447.GA23759@sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Jeff Garzik reported this WARN_ON() noise:

> Kernel: 2.6.30-rc1-00306-g8371f87c
> Hardware: ICH10 x86-64
>
> This is a regression from 2.6.29.  Microcode spews the following WARNING
> multiple times during boot:
>
> ------------[ cut here ]------------
> WARNING: at fs/sysfs/group.c:138 sysfs_remove_group+0xeb/0xf0()
> Hardware name:         sysfs group ffffffffa0209700 not found for
>  kobject 'cpu0'

Keep sysfs files around for cpus even when we failed to locate
microcode for them at the moment of module loading. The appropriate
microcode firmware can become available later on.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This patch correctly sets BAU memory mapped registers to point
to the sending activation descriptor table and target payload table.

The "Broadcast Assist Unit" is used for TLB shootdown in UV.

The memory mapped registers that point to sending and receiving
memory structures contain node numbers.

In one case the __pa() function did not provide the node id of
memory on blade zero in configurations where that id is nonzero.
In another case, it was assumed that memory was allocated on
the local node.  That assumption is not true in a configuration
in which the node has no memory.

Tested on the UV hardware simulator.

[ Impact: fix possible runtime crash due to incorrect TLB logic ]
Signed-off-by: NCliff Wickman <cpw@sgi.com>
LKML-Reference: <E1LuR5Z-0007An-B8@eag09.americas.sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

It turns out that 'smp_call_function_many()' doesn't work at all like
'smp_call_function_single()', and my change to Andrew's patch to use it
rather than a loop over all CPU's acpi-cpufreq doesn't work.

My bad.

'smp_call_function_many()' has two "features" (aka "documented bugs"):

 (a) it needs to be called with preemption disabled, because it uses
     smp_processor_id() without guarding the CPU lookup with 'get_cpu()'
     and 'put_cpu()' like the 'single' variant does.

 (b) even if the current CPU is part of the CPU mask, it won't do the
     call on that CPU.

Still, we're better off trying to use 'smp_call_function_many()' than
looping over CPU's, since it at least in theory allows us to use a
broadcast IPI and do it all in parallel.  So let's just work around the
silly semantic bugs in that function.
Reported-and-tested-by: NAli Gholami Rudi <ali@rudi.ir>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Revert part of af5c820a ("x86: cpumask:
use work_on_cpu in arch/x86/kernel/microcode_core.c")

That change is causing only one Intel CPU's microcode to be updated e.g.
microcode: CPU3 updated from revision 0x9 to 0x17, date = 2005-04-22
where before it announced that also for CPU0 and CPU1 and CPU2.

We cannot use work_on_cpu() in the CONFIG_MICROCODE_OLD_INTERFACE code,
because Intel's request_microcode_user() involves a copy_from_user() from
/sbin/microcode_ctl, which therefore needs to be on that CPU at the time.
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch enables each partition's BAU distribution bit map
to be partition-relative.

The distribution bitmap had been constructed assuming 0 as the base
node number.  That construct would not have allowed a total system of
greater than 256 nodes.
It also corrects an error that occurred when the first blade's nasid
was not zero.  That nasid was stored as the base node.
The base node number gets added by hardware to the node numbers implied
in the distribution bitmap, resulting in invalid target nasids.

Tested on the UV hardware simulator.
Signed-off-by: NCliff Wickman <cpw@sgi.com>
LKML-Reference: <E1Ltl0C-0004Ob-37@eag09.americas.sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

As discussed in the thread here:

  http://marc.info/?l=linux-kernel&m=123964468521142&w=2

Eric W. Biederman observed:

> It looks like some additional bugs have slipped in since last I looked.
>
> set_irq_affinity does this:
> ifdef CONFIG_GENERIC_PENDING_IRQ
>        if (desc->status & IRQ_MOVE_PCNTXT || desc->status & IRQ_DISABLED) {
>                cpumask_copy(desc->affinity, cpumask);
>                desc->chip->set_affinity(irq, cpumask);
>        } else {
>                desc->status |= IRQ_MOVE_PENDING;
>                cpumask_copy(desc->pending_mask, cpumask);
>        }
> #else
>
> That IRQ_DISABLED case is a software state and as such it has nothing to
> do with how safe it is to move an irq in process context.

[...]

>
> The only reason we migrate MSIs in interrupt context today is that there
> wasn't infrastructure for support migration both in interrupt context
> and outside of it.

Yes. The idea here was to force the MSI migration to happen in process
context. One of the patches in the series did

        disable_irq(dev->irq);
        irq_set_affinity(dev->irq, cpumask_of(dev->cpu));
        enable_irq(dev->irq);

with the above patch adding irq/manage code check for interrupt disabled
and moving the interrupt in process context.

IIRC, there was no IRQ_MOVE_PCNTXT when we were developing this HPET
code and we ended up having this ugly hack. IRQ_MOVE_PCNTXT was there
when we eventually submitted the patch upstream. But, looks like I did a
blind rebasing instead of using IRQ_MOVE_PCNTXT in hpet MSI code.

Below patch fixes this. i.e., revert commit 932775a4
and add PCNTXT to HPET MSI setup. Also removes copying of desc->affinity
in generic code as set_affinity routines are doing it internally.
Reported-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Acked-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Li Shaohua" <shaohua.li@intel.com>
Cc: Gary Hade <garyhade@us.ibm.com>
Cc: "lcm@us.ibm.com" <lcm@us.ibm.com>
Cc: suresh.b.siddha@intel.com
LKML-Reference: <20090413222058.GB8211@linux-os.sc.intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

We ended up incorrectly using '&cur' instead of '&readin' in the
work_on_cpu() -> smp_call_function_single() transformation in commit
01599fca ("cpufreq: use
smp_call_function_[single|many]() in acpi-cpufreq.c").

Andrew explains:
 "OK, the acpi tree went and had conflicting changes merged into it after
  I'd written the patch and it appears that I incorrectly reverted part
  of 18b2646f while fixing the resulting
  rejects.

  Switching it to `readin' looks correct."
Acked-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Impact: reduce kernel size a bit, address sparse warning

Addresses the problem pointed out by this sparse warning:

  arch/x86/kernel/pci-swiotlb.c:53:20: warning: symbol 'swiotlb_dma_ops' was not declared. Should it be static?

For x86: swiotlb_dma_ops can be static, because it's not used outside
of pci-swiotlb.c
Signed-off-by: NJaswinder Singh Rajput <jaswinderrajput@gmail.com>
Acked-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
LKML-Reference: <1239558861.3938.2.camel@localhost.localdomain>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Atttempting to rid us of the problematic work_on_cpu().  Just use
smp_call_fuction_single() here.

This repairs a 10% sysbench(oltp)+mysql regression which Mike reported,
due to

  commit 6b44003e
  Author: Andrew Morton <akpm@linux-foundation.org>
  Date:   Thu Apr 9 09:50:37 2009 -0600

      work_on_cpu(): rewrite it to create a kernel thread on demand

It seems that the kernel calls these acpi-cpufreq functions at a quite
high frequency.

Valdis Kletnieks also reports that this causes 70-90 forks per second on
his hardware.

Cc: Valdis.Kletnieks@vt.edu
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Zhao Yakui <yakui.zhao@intel.com>
Acked-by: NDave Jones <davej@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Tested-by: NMike Galbraith <efault@gmx.de>
Cc: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NIngo Molnar <mingo@elte.hu>
[ Made it use smp_call_function_many() instead of looping over cpu's
  with smp_call_function_single()    - Linus ]
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Impact: save/restore Intel-AVX state properly between tasks

Intel Advanced Vector Extensions (AVX) introduce 256-bit vector processing
capability. More about AVX at http://software.intel.com/sites/avx

Add OS support for YMM state management using xsave/xrstor infrastructure
to support AVX.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <1239402084.27006.8057.camel@localhost.localdomain>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: fix section mismatch

In arch/x86/kernel/mpparse.c, smp_reserve_bootmem() has been called
and also refers to a function which is in .init section. Thus causes
the first warning. And check_irq_src() also requires an __init,
because it refers to an .init section.
Signed-off-by: NRakib Mullick <rakib.mullick@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <b9df5fa10904102004g51265d9axc8d07278bfdb6ba0@mail.gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

To simplify level irq migration in the presence of interrupt-remapping,
Suresh used a virtual vector (io-apic pin number) to eliminate io-apic
RTE modification. Level triggered interrupt will appear as an edge to
the local apic cpu but still as level to the IO-APIC. So in addition to
do the local apic EOI, it still needs to do IO-APIC directed EOI to clear
the remote IRR bit in the IO-APIC RTE. Pls refer to Suresh's patch for
more details (commit 0280f7c4).

Now interrupt remapping is decoupled from x2apic, it also needs to do the
directed EOI for apic. Otherwise, apic interrupts won't work correctly.
Signed-off-by: NWeidong Han <weidong.han@intel.com>
Cc: iommu@lists.linux-foundation.org
Cc: Weidong Han <weidong.han@intel.com>
Cc: suresh.b.siddha@intel.com
Cc: dwmw2@infradead.org
Cc: allen.m.kay@intel.com
LKML-Reference: <1239355037-22856-1-git-send-email-weidong.han@intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

It seems by mistake these files got execute permissions so removing it.
Signed-off-by: NJaswinder Singh Rajput <jaswinderrajput@gmail.com>
LKML-Reference: <1239211186.9037.2.camel@ht.satnam>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: fix build warnings and possibe compat misbehavior on IA64

Building a kernel on ia64 might trigger these ugly build warnings:

CC      arch/ia64/ia32/sys_ia32.o
In file included from arch/ia64/ia32/sys_ia32.c:55:
arch/ia64/ia32/ia32priv.h:290:1: warning: "elf_check_arch" redefined
In file included from include/linux/elf.h:7,
                 from include/linux/module.h:14,
                 from include/linux/ftrace.h:8,
                 from include/linux/syscalls.h:68,
                 from arch/ia64/ia32/sys_ia32.c:18:
arch/ia64/include/asm/elf.h:19:1: warning: this is the location of the previous definition
[...]

sys_ia32.c includes linux/syscalls.h which in turn includes linux/ftrace.h
to import the syscalls tracing prototypes.

But including ftrace.h can pull too much things for a low level file,
especially on ia64 where the ia32 private headers conflict with higher
level headers.

Now we isolate the syscall tracing headers in their own lightweight file.
Reported-by: NTony Luck <tony.luck@intel.com>
Tested-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Acked-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Jason Baron <jbaron@redhat.com>
Cc: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Michael Rubin <mrubin@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Michael Davidson <md@google.com>
LKML-Reference: <20090408184058.GB6017@nowhere>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

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

  PLT: Platform interrupts

Format change of output, as like that by commit:

  commit 7a81d9a7
  x86: smarten /proc/interrupts output

should be applied to these new counters too.
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Jan Beulich <jbeulich@novell.com>
LKML-Reference: <49C98DEA.8060208@jp.fujitsu.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Closes http://bugzilla.kernel.org/show_bug.cgi?12901Signed-off-by: NAlan Cox <alan@lxorguk.ukuu.org.uk>
LKML-Reference: <20090326204524.4454.8776.stgit@localhost.localdomain>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: restore old behavior

for flat and phys_flat

Signed-off-by: Yinhai Lu <yinghai@kernel.org.
LKML-Reference: <49DCBBF1.8080903@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

/sys/firmware/sgi_uv should only be created on uv systems.
Signed-off-by: NRuss Anderson <rja@sgi.com>
LKML-Reference: <20090403222423.GA28546@sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>