Move the irqstackptr variable from the PDA to per-cpu.  Make the
stacks themselves per-cpu, removing some specific allocation code.
Add a seperate flag (is_boot_cpu) to simplify the per-cpu boot
adjustments.

tj: * sprinkle some underbars around.

    * irq_stack_ptr is not used till traps_init(), no reason to
      initialize it early.  On SMP, just leaving it NULL till proper
      initialization in setup_per_cpu_areas() works.  Dropped
      is_boot_cpu and early irq_stack_ptr initialization.

    * do DECLARE/DEFINE_PER_CPU(char[IRQ_STACK_SIZE], irq_stack)
      instead of (char, irq_stack[IRQ_STACK_SIZE]).
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

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

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

arm, arm/mach-integrator and powerpc were missing
.data.percpu.page_aligned in their percpu output section definitions.
Add it.
Signed-off-by: Tejun Heo <tj@kernel.org>

The newly added PERCPU_*() macros define and use __per_cpu_load but
VMLINUX_SYMBOL() was missing from usages causing build failures on
archs where linker visible symbol is different from C symbols
(e.g. blackfin).
Signed-off-by: Tejun Heo <tj@kernel.org>

On x86_64, if get_per_cpu_var() is used before per cpu area is setup
(if lockdep is turned on, it happens), it needs this_cpu_off to point
to __per_cpu_load.  Initialize accordingly.
Signed-off-by: Tejun Heo <tj@kernel.org>

EXPORT_PER_CPU_SYMBOL() got misplaced during merge leading to build
failure.  Fix it.
Signed-off-by: Tejun Heo <tj@kernel.org>

It is an optimization and a cleanup, and adds the following new
generic percpu methods:

  percpu_read()
  percpu_write()
  percpu_add()
  percpu_sub()
  percpu_and()
  percpu_or()
  percpu_xor()

and implements support for them on x86. (other architectures will fall
back to a default implementation)

The advantage is that for example to read a local percpu variable,
instead of this sequence:

 return __get_cpu_var(var);

 ffffffff8102ca2b:	48 8b 14 fd 80 09 74 	mov    -0x7e8bf680(,%rdi,8),%rdx
 ffffffff8102ca32:	81
 ffffffff8102ca33:	48 c7 c0 d8 59 00 00 	mov    $0x59d8,%rax
 ffffffff8102ca3a:	48 8b 04 10          	mov    (%rax,%rdx,1),%rax

We can get a single instruction by using the optimized variants:

 return percpu_read(var);

 ffffffff8102ca3f:	65 48 8b 05 91 8f fd 	mov    %gs:0x7efd8f91(%rip),%rax

I also cleaned up the x86-specific APIs and made the x86 code use
these new generic percpu primitives.

tj: * fixed generic percpu_sub() definition as Roel Kluin pointed out
    * added percpu_and() for completeness's sake
    * made generic percpu ops atomic against preemption
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Tejun Heo <tj@kernel.org>

Do the following cleanups:

* kill x86_64_init_pda() which now is equivalent to pda_init()

* use per_cpu_offset() instead of cpu_pda() when initializing
  initial_gs
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

pda is now a percpu variable and there's no reason it can't use plain
x86 percpu accessors.  Add x86_test_and_clear_bit_percpu() and replace
pda op implementations with wrappers around x86 percpu accessors.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

[ Based on original patch from Christoph Lameter and Mike Travis. ]

As pda is now allocated in percpu area, it can easily be made a proper
percpu variable.  Make it so by defining per cpu symbol from linker
script and declaring it in C code for SMP and simply defining it for
UP.  This change cleans up code and brings SMP and UP closer a bit.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Now that pda is allocated as part of percpu, percpu doesn't need to be
accessed through pda.  Unify x86_64 SMP percpu access with x86_32 SMP
one.  Other than the segment register, operand size and the base of
percpu symbols, they behave identical now.

This patch replaces now unnecessary pda->data_offset with a dummy
field which is necessary to keep stack_canary at its place.  This
patch also moves per_cpu_offset initialization out of init_gdt() into
setup_per_cpu_areas().  Note that this change also necessitates
explicit per_cpu_offset initializations in voyager_smp.c.

With this change, x86_OP_percpu()'s are as efficient on x86_64 as on
x86_32 and also x86_64 can use assembly PER_CPU macros.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

[ Based on original patch from Christoph Lameter and Mike Travis. ]

Currently pdas and percpu areas are allocated separately.  %gs points
to local pda and percpu area can be reached using pda->data_offset.
This patch folds pda into percpu area.

Due to strange gcc requirement, pda needs to be at the beginning of
the percpu area so that pda->stack_canary is at %gs:40.  To achieve
this, a new percpu output section macro - PERCPU_VADDR_PREALLOC() - is
added and used to reserve pda sized chunk at the start of the percpu
area.

After this change, for boot cpu, %gs first points to pda in the
data.init area and later during setup_per_cpu_areas() gets updated to
point to the actual pda.  This means that setup_per_cpu_areas() need
to reload %gs for CPU0 while clearing pda area for other cpus as cpu0
already has modified it when control reaches setup_per_cpu_areas().

This patch also removes now unnecessary get_local_pda() and its call
sites.

A lot of this patch is taken from Mike Travis' "x86_64: Fold pda into
per cpu area" patch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

_cpu_pda array first uses statically allocated storage in data.init
and then switches to allocated bootmem to conserve space.  However,
after folding pda area into percpu area, _cpu_pda array will be
removed completely.  Drop the reallocation part to simplify the code
for soon-to-follow changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

[ Based on original patch from Christoph Lameter and Mike Travis. ]

CPU startup code in head_64.S loaded address of a zero page into %gs
for temporary use till pda is loaded but address to the actual pda is
available at the point.  Load the real address directly instead.

This will help unifying percpu and pda handling later on.

This patch is mostly taken from Mike Travis' "x86_64: Fold pda into
per cpu area" patch.
Signed-off-by: Tejun Heo <tj@kernel.org>

[ Based on original patch from Christoph Lameter and Mike Travis. ]

This patch makes percpu symbols zerobased on x86_64 SMP by adding
PERCPU_VADDR() to vmlinux.lds.h which helps setting explicit vaddr on
the percpu output section and using it in vmlinux_64.lds.S.  A new
PHDR is added as existing ones cannot contain sections near address
zero.  PERCPU_VADDR() also adds a new symbol __per_cpu_load which
always points to the vaddr of the loaded percpu data.init region.

The following adjustments have been made to accomodate the address
change.

* code to locate percpu gdt_page in head_64.S is updated to add the
  load address to the gdt_page offset.

* __per_cpu_load is used in places where access to the init data area
  is necessary.

* pda->data_offset is initialized soon after C code is entered as zero
  value doesn't work anymore.

This patch is mostly taken from Mike Travis' "x86_64: Base percpu
variables at zero" patch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Make vmlinux_32.lds.S use the generic PERCPU() macro instead of open
coding it.  This will ease future changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

[ Based on original patch from Christoph Lameter and Mike Travis. ]

  * Ruggedize some calls in setup_percpu.c to prevent mishaps
    in early calls, particularly for non-critical functions.

  * Cleanup DEBUG_PER_CPU_MAPS usages and some comments.
Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Make early_per_cpu() a lvalue as per_cpu() is and use it where
applicable.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

There's no instruction to move a 64bit immediate into memory location.
Drop "i".
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Impact: cleanup

Use the proper type.
Signed-off-by: Ingo Molnar <mingo@elte.hu>

E.g. when called due to an early panic.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Impact: widen the effect of the 'nolapic' boot parameter

"nolapic" should not only suppress SMP and use of the LAPIC, but it
also ought to have the effect of disabling all IO-APIC related activity
as well as PCI MSI and HT-IRQs.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Impact: fix build errors

Since the SPARSE IRQS changes redefined how the kstat irqs are
organized, arch's must use the new accessor function:

	kstat_incr_irqs_this_cpu(irq, DESC);

If CONFIG_SPARSE_IRQS is set, then DESC is a pointer to the
irq_desc which has a pointer to the kstat_irqs.  If not, then
the .irqs field of struct kernel_stat is used instead.
Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Thierry Vignaud reported:
> http://bugzilla.kernel.org/show_bug.cgi?id=12372
>
> On P4 with an SiS motherboard (video card is a SiS 651)
> X server fails to start with error:
> xf86MapVidMem: Could not mmap framebuffer (0x00000000,0x2000) (Invalid
> argument)

Here X is trying to map first 8KB of memory using /dev/mem. Existing
code treats first 0-4KB of memory as non-RAM and 4KB-8KB as RAM. Recent
code changes don't allow to map memory with different attributes
at the same time.

Fix this by treating the first 1MB legacy region as special and always
track the attribute requests with in this region using linear linked
list (and don't bother if the range is RAM or non-RAM or mixed)
Reported-and-tested-by: Thierry Vignaud <tvignaud@mandriva.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Impact: clean up to be same as 64bit

32-bit is using per-cpu vector too, so don't use default NR_IRQS.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Merge branch 'master' of ssh://master.kernel.org/pub/scm/linux/kernel/git/travis/linux-2.6-cpus4096-for-ingo into cpus4096

Impact: cleanup, solve 80 columns wrap problems
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Impact: cleanup, solve 80 columns wrap problems
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

This commit broke flush_tlb_others_ipi() causing boot hangs on a
16 logical cpu system:

>	commit 4595f962
>	Author: Rusty Russell <rusty@rustcorp.com.au>
>	Date:   Sat Jan 10 21:58:09 2009 -0800
>
>	    x86: change flush_tlb_others to take a const struct cpumask

This change resulted in sending the invalidate tlb vector to the
sender itself causing the hang. flush_tlb_others_ipi() should exclude
the sender itself from the destination list.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

* 'x86-pat-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86 PAT: remove CPA WARN_ON for zero pte
  x86 PAT: return compatible mapping to remap_pfn_range callers
  x86 PAT: change track_pfn_vma_new to take pgprot_t pointer param
  x86 PAT: consolidate old memtype new memtype check into a function
  x86 PAT: remove PFNMAP type on track_pfn_vma_new() error

* master.kernel.org:/home/rmk/linux-2.6-arm:
  TWL4030: fix clk API usage
  [ARM] 5364/1: allow flush_ioremap_region() to be used from modules
  [ARM] w90x900: fix build errors and warnings
  [ARM] i.MX add missing include
  [ARM] i.MX: fix breakage from commit 27889273
  [ARM] i.MX: remove LCDC controller register definitions from imx-regs.h

Since we (Analog Devices) updated our Blackfin kernel to 2.6.28, we've
seen occasional 5-second hangs from telnet.  telnetd calls select with a
NULL timeout, but with the new kernel, the system call occasionally
returns 0, which causes telnet to call sleep (5).  This did not happen
with earlier kernels.

The code in sys_pselect7 looks a bit strange, in particular the variable
"to" is initialized to NULL, then changed if a non-null timeout was
passed in, but not used further.  It needs to be passed to
core_sys_select instead of &end_time.

This bug was introduced by 8ff3e8e8
("select: switch select() and poll() over to hrtimers").
Signed-off-by: Bernd Schmidt <bernd.schmidt@analog.com>
Reviewed-by: Ulrich Drepper <drepper@redhat.com>
Tested-by: Robin Getz <rgetz@blackfin.uclinux.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit b430428a ("8250: Don't clobber
spinlocks.") introduced a regression on the parisc architecture, which
broke the handover to the serial port at boottime.

early_serial_setup() was changed to only copy a subset of the uart_port
fields, and sadly the "type" and "line" fields were forgotten and thus
the serial port was not initialized and could not be used for a
handover.  This patch fixes this by copying the missing fields.

As this change to early_serial_setup() doesn't need an initialized
spinlock in the uart_port struct any longer, we can drop the spinlock
initialization in the superio driver.

Cc: David Daney <ddaney@caviumnetworks.com>
Cc: Tomaso Paoletti <tpaoletti@caviumnetworks.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: Kyle McMartin <kyle@mcmartin.ca>
Cc: linux-parisc@vger.kernel.org
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Always pass a struct device if one is available; and there's really
no reason for the processor specific stuff in this file if only
people would follow the API usage properly by using the struct device.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Impact: reduce scope of debug check - avoid warnings

The logic to find whether identity map exists or not using
high_memory or max_low_pfn_mapped/max_pfn_mapped are not complete
as the memory withing the range may not be mapped if there is a
unusable hole in e820.

Specifically, on my test system I started seeing these warnings with
tools like hwinfo, acpidump trying to map ACPI region.

[   27.400018] ------------[ cut here ]------------
[   27.400344] WARNING: at /home/venkip/src/linus/linux-2.6/arch/x86/mm/pageattr.c:560 __change_page_attr_set_clr+0xf3/0x8b8()
[   27.400821] Hardware name: X7DB8
[   27.401070] CPA: called for zero pte. vaddr = ffff8800cff6a000 cpa->vaddr = ffff8800cff6a000
[   27.401569] Modules linked in:
[   27.401882] Pid: 4913, comm: dmidecode Not tainted 2.6.28-05716-gfe0bdec6 #586
[   27.402141] Call Trace:
[   27.402488]  [<ffffffff80237c21>] warn_slowpath+0xd3/0x10f
[   27.402749]  [<ffffffff80274ade>] ? find_get_page+0xb3/0xc9
[   27.403028]  [<ffffffff80274a2b>] ? find_get_page+0x0/0xc9
[   27.403333]  [<ffffffff80226425>] __change_page_attr_set_clr+0xf3/0x8b8
[   27.403628]  [<ffffffff8028ec99>] ? __purge_vmap_area_lazy+0x192/0x1a1
[   27.403883]  [<ffffffff8028eb52>] ? __purge_vmap_area_lazy+0x4b/0x1a1
[   27.404172]  [<ffffffff80290268>] ? vm_unmap_aliases+0x1ab/0x1bb
[   27.404512]  [<ffffffff80290105>] ? vm_unmap_aliases+0x48/0x1bb
[   27.404766]  [<ffffffff80226d28>] change_page_attr_set_clr+0x13e/0x2e6
[   27.405026]  [<ffffffff80698fa7>] ? _spin_unlock+0x26/0x2a
[   27.405292]  [<ffffffff80227e6a>] ? reserve_memtype+0x19b/0x4e3
[   27.405590]  [<ffffffff80226ffd>] _set_memory_wb+0x22/0x24
[   27.405844]  [<ffffffff80225d28>] ioremap_change_attr+0x26/0x28
[   27.406097]  [<ffffffff80228355>] reserve_pfn_range+0x1a3/0x235
[   27.406427]  [<ffffffff80228430>] track_pfn_vma_new+0x49/0xb3
[   27.406686]  [<ffffffff80286c46>] remap_pfn_range+0x94/0x32c
[   27.406940]  [<ffffffff8022878d>] ? phys_mem_access_prot_allowed+0xb5/0x1a8
[   27.407209]  [<ffffffff803e9bf4>] mmap_mem+0x75/0x9d
[   27.407523]  [<ffffffff8028b3b4>] mmap_region+0x2cf/0x53e
[   27.407776]  [<ffffffff8028b8cc>] do_mmap_pgoff+0x2a9/0x30d
[   27.408034]  [<ffffffff8020f4a4>] sys_mmap+0x92/0xce
[   27.408339]  [<ffffffff8020b65b>] system_call_fastpath+0x16/0x1b
[   27.408614] ---[ end trace 4b16ad70c09a602d ]---
[   27.408871] dmidecode:4913 reserve_pfn_range ioremap_change_attr failed write-back for cff6a000-cff6b000

This is wih track_pfn_vma_new trying to keep identity map in sync.
The address cff6a000 is the ACPI region according to e820.

[    0.000000] BIOS-provided physical RAM map:
[    0.000000]  BIOS-e820: 0000000000000000 - 000000000009c000 (usable)
[    0.000000]  BIOS-e820: 000000000009c000 - 00000000000a0000 (reserved)
[    0.000000]  BIOS-e820: 00000000000cc000 - 00000000000d0000 (reserved)
[    0.000000]  BIOS-e820: 00000000000e4000 - 0000000000100000 (reserved)
[    0.000000]  BIOS-e820: 0000000000100000 - 00000000cff60000 (usable)
[    0.000000]  BIOS-e820: 00000000cff60000 - 00000000cff69000 (ACPI data)
[    0.000000]  BIOS-e820: 00000000cff69000 - 00000000cff80000 (ACPI NVS)
[    0.000000]  BIOS-e820: 00000000cff80000 - 00000000d0000000 (reserved)
[    0.000000]  BIOS-e820: 00000000e0000000 - 00000000f0000000 (reserved)
[    0.000000]  BIOS-e820: 00000000fec00000 - 00000000fec10000 (reserved)
[    0.000000]  BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
[    0.000000]  BIOS-e820: 00000000ff000000 - 0000000100000000 (reserved)
[    0.000000]  BIOS-e820: 0000000100000000 - 0000000230000000 (usable)

And is not mapped as per init_memory_mapping.

[    0.000000] init_memory_mapping: 0000000000000000-00000000cff60000
[    0.000000] init_memory_mapping: 0000000100000000-0000000230000000

We can add logic to check for this. But, there can also be other holes in
identity map when we have 1GB of aligned reserved space in e820.

This patch handles it by removing the WARN_ON and returning a specific
error value (EFAULT) to indicate that the address does not have any
identity mapping.

The code that tries to keep identity map in sync can ignore
this error, with other callers of cpa still getting error here.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Impact: avoid warning message, potentially solve 3D performance regression

Change x86 PAT code to return compatible memtype if the exact memtype that
was requested in remap_pfn_rage and friends is not available due to some
conflict.

This is done by returning the compatible type in pgprot parameter of
track_pfn_vma_new(), and the caller uses that memtype for page table.

Note that track_pfn_vma_copy() which is basically called during fork gets the
prot from existing page table and should not have any conflict. Hence we use
strict memtype check there and do not allow compatible memtypes.

This patch fixes the bug reported here:

  http://marc.info/?l=linux-kernel&m=123108883716357&w=2

Specifically the error message:

  X:5010 map pfn expected mapping type write-back for d0000000-d0101000,
  got write-combining

Should go away.
Reported-and-bisected-by: Kevin Winchester <kjwinchester@gmail.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Impact: cleanup

Change the protection parameter for track_pfn_vma_new() into a pgprot_t pointer.
Subsequent patch changes the x86 PAT handling to return a compatible
memtype in pgprot_t, if what was requested cannot be allowed due to conflicts.
No fuctionality change in this patch.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Impact: cleanup

Move the new memtype old memtype allowed check to header so that is can be
shared by other users. Subsequent patch uses this in pat.c in remap_pfn_range()
code path. No functionality change in this patch.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>