Ingo Molnar [Fri, 23 Jan 2009 10:09:15 +0000 (11:09 +0100)]
x86, xen: fix hardirq.h merge fallout
Impact: build fix
This build error:
arch/x86/xen/suspend.c:22: error: implicit declaration of function 'fix_to_virt'
arch/x86/xen/suspend.c:22: error: 'FIX_PARAVIRT_BOOTMAP' undeclared (first use in this function)
arch/x86/xen/suspend.c:22: error: (Each undeclared identifier is reported only once
arch/x86/xen/suspend.c:22: error: for each function it appears in.)
triggers because the hardirq.h unification removed an implicit fixmap.h
include - on which arch/x86/xen/suspend.c depended. Add the fixmap.h
include explicitly.
Ingo Molnar [Wed, 21 Jan 2009 09:32:44 +0000 (10:32 +0100)]
x86: make x86_32 use tlb_64.c, build fix, clean up X86_L1_CACHE_BYTES
Fix:
arch/x86/mm/tlb.c:47: error: ‘CONFIG_X86_INTERNODE_CACHE_BYTES’ undeclared here (not in a function)
The CONFIG_X86_INTERNODE_CACHE_BYTES symbol is only defined on 64-bit,
because vsmp support is 64-bit only. Define it on 32-bit too - where it
will always be equal to X86_L1_CACHE_BYTES.
Also move the default of X86_L1_CACHE_BYTES (which is separate from the
more commonly used L1_CACHE_SHIFT kconfig symbol) from 128 bytes to
64 bytes.
Ingo Molnar [Wed, 21 Jan 2009 09:24:27 +0000 (10:24 +0100)]
x86: uv cleanup, build fix
Fix:
arch/x86/mm/srat_64.c: In function ‘acpi_numa_processor_affinity_init’:
arch/x86/mm/srat_64.c:141: error: implicit declaration of function ‘get_uv_system_type’
arch/x86/mm/srat_64.c:141: error: ‘UV_X2APIC’ undeclared (first use in this function)
arch/x86/mm/srat_64.c:141: error: (Each undeclared identifier is reported only once
arch/x86/mm/srat_64.c:141: error: for each function it appears in.)
A couple of UV definitions were moved to asm/uv/uv.h, but srat_64.c did
not include that header. Add it.
Merge it here because both the cpumask changes and the ongoing percpu
work is touching the TLB code. The percpu changes take precedence, as
they eliminate tlb_32.c altogether.
Tejun Heo [Wed, 21 Jan 2009 08:26:06 +0000 (17:26 +0900)]
x86: make x86_32 use tlb_64.c
Impact: less contention when issuing invalidate IPI, cleanup
Make x86_32 use the same tlb code as 64bit. The 64bit code uses
multiple IPI vectors for tlb shootdown to reduce contention. This
patch makes x86_32 allocate the same 8 IPIs as x86_64 and share the
code paths.
Note that the usage of asmlinkage is inconsistent for x86_32 and 64
and calls for further cleanup. This has been noted with a FIXME
comment in tlb_64.c.
Tejun Heo [Wed, 21 Jan 2009 08:26:06 +0000 (17:26 +0900)]
x86: prepare for tlb merge
Impact: clean up, ipi vector number reordering for x86_32
Make the following changes to prepare for tlb merge.
* reorder x86_32 ip vectors
* adjust tlb_32.c and tlb_64.c such that their logics coincide exactly
- on spurious invalidate ipi, tlb_32 acks the irq
- tlb_64 now has proper memory barriers around clearing
flush_cpumask (no change in generated code)
* unexport flush_tlb_page from tlb_32.c, there's no user
Tejun Heo [Wed, 21 Jan 2009 08:26:06 +0000 (17:26 +0900)]
x86: uv cleanup
Impact: cleanup
Make the following uv related cleanups.
* collect visible uv related definitions and interfaces into uv/uv.h
and use it. this cleans up the messy situation where on 64bit, uv
is defined properly, on 32bit generic it's dummy and on the rest
undefined. after this clean up, uv is defined on 64 and dummy on
32.
* update uv_flush_tlb_others() such that it takes cpumask of
to-be-flushed cpus as argument, instead of that minus self, and
returns yet-to-be-flushed cpumask, instead of modifying the passed
in parameter. this interface change will ease dummy implementation
of uv_flush_tlb_others() and makes uv tlb flush related stuff
defined in tlb_uv proper.
Brian Gerst [Wed, 21 Jan 2009 08:26:06 +0000 (17:26 +0900)]
x86: merge mmu_context.h
Impact: cleanup
tj: * changed cpu to unsigned as was done on mmu_context_64.h as cpu
id is officially unsigned int
* added missing ';' to 32bit version of deactivate_mm()
Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
Brian Gerst [Wed, 21 Jan 2009 08:26:05 +0000 (17:26 +0900)]
x86: set %fs to __KERNEL_PERCPU unconditionally for x86_32
Impact: cleanup
%fs is currently set to __KERNEL_DS at boot, and conditionally
switched to __KERNEL_PERCPU for secondary cpus. Instead, initialize
GDT_ENTRY_PERCPU to the same attributes as GDT_ENTRY_KERNEL_DS and
set %fs to __KERNEL_PERCPU unconditionally.
Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
Brian Gerst [Wed, 21 Jan 2009 08:26:05 +0000 (17:26 +0900)]
x86: fix percpu_write with 64-bit constants
Impact: slightly better code generation for percpu_to_op()
The processor will sign-extend 32-bit immediate values in 64-bit
operations. Use the 'e' constraint ("32-bit signed integer constant,
or a symbolic reference known to fit that range") for 64-bit constants.
Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
Nick Piggin [Tue, 20 Jan 2009 03:24:26 +0000 (04:24 +0100)]
x86: optimise x86's do_page_fault (C entry point for the page fault path)
Impact: cleanup, restructure code to improve assembly
gcc isn't _all_ that smart about spilling registers to stack or reusing
stack slots, even with branch annotations. do_page_fault contained a lot
of functionality, so split unlikely paths into their own functions, and
mark them as noinline just to be sure. I consider this actually to be
somewhat of a cleanup too: the main function now contains about half
the number of lines so the normal path is easier to read, while the error
cases are also nicely split away.
Also, ensure the order of arguments to functions is always the same: regs,
addr, error_code. This can reduce code size a tiny bit, and just looks neater
too.
Yes, the total size increases by 542 bytes, due to the extra function calls.
But these will very rarely be called (except for vmalloc_fault) in a normal
workload. Importantly, do_page_fault is less than 1/3rd it's original size,
and touches far less stack.
Existing gotos and branch hints did move a lot of the infrequently used text
out of the fastpath, but that's even further improved after this patch.
Brian Gerst [Mon, 19 Jan 2009 03:21:28 +0000 (12:21 +0900)]
x86: move stack_canary into irq_stack
Impact: x86_64 percpu area layout change, irq_stack now at the beginning
Now that the PDA is empty except for the stack canary, it can be removed.
The irqstack is moved to the start of the per-cpu section. If the stack
protector is enabled, the canary overlaps the bottom 48 bytes of the irqstack.
tj: * updated subject
* dropped asm relocation of irq_stack_ptr
* updated comments a bit
* rebased on top of stack canary changes
Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
Brian Gerst [Mon, 19 Jan 2009 03:21:27 +0000 (12:21 +0900)]
x86: remove pda_init()
Impact: cleanup
Copy the code to cpu_init() to satisfy the requirement that the cpu
be reinitialized. Remove all other calls, since the segments are
already initialized in head_64.S.
Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
Brian Gerst [Sun, 18 Jan 2009 15:38:59 +0000 (00:38 +0900)]
x86-64: Use absolute displacements for per-cpu accesses.
Accessing memory through %gs should not use rip-relative addressing.
Adding a P prefix for the argument tells gcc to not add (%rip) to
the memory references.
Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
Brian Gerst [Sun, 18 Jan 2009 15:38:58 +0000 (00:38 +0900)]
x86-64: Convert irqstacks to per-cpu
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>
Tejun Heo [Sat, 17 Jan 2009 05:42:50 +0000 (14:42 +0900)]
linker script: add missing VMLINUX_SYMBOL
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).
Mike Travis [Fri, 16 Jan 2009 23:31:15 +0000 (15:31 -0800)]
cpufreq: use work_on_cpu in acpi-cpufreq.c for drv_read and drv_write
Impact: use new work_on_cpu function to reduce stack usage
Replace the saving of current->cpus_allowed and set_cpus_allowed_ptr() with
a work_on_cpu function for drv_read() and drv_write().
Basically converts do_drv_{read,write} into "work_on_cpu" functions that
are now called by drv_read and drv_write.
Note: This patch basically reverts 50c668d6 which reverted 7503bfba, now
that the work_on_cpu() function is more stable.
Signed-off-by: Mike Travis <travis@sgi.com> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Tested-by: Dieter Ries <clip2@gmx.de> Tested-by: Maciej Rutecki <maciej.rutecki@gmail.com> Cc: Dave Jones <davej@redhat.com> Cc: <cpufreq@vger.kernel.org>
Rusty Russell [Fri, 16 Jan 2009 23:31:15 +0000 (15:31 -0800)]
work_on_cpu: Use our own workqueue.
Impact: remove potential clashes with generic kevent workqueue
Annoyingly, some places we want to use work_on_cpu are already in
workqueues. As per Ingo's suggestion, we create a different workqueue
for work_on_cpu.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Mike Travis <travis@sgi.com>
Rusty Russell [Fri, 16 Jan 2009 23:31:15 +0000 (15:31 -0800)]
work_on_cpu: don't try to get_online_cpus() in work_on_cpu.
Impact: remove potential circular lock dependency with cpu hotplug lock
This has caused more problems than it solved, with a pile of cpu
hotplug locking issues.
Followup patches will get_online_cpus() in callers that need it, but
if they don't do it they're no worse than before when they were using
set_cpus_allowed without locking.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Mike Travis <travis@sgi.com>
Linus Torvalds [Fri, 16 Jan 2009 20:40:37 +0000 (12:40 -0800)]
Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6: (23 commits)
ACPI PCI hotplug: harden against panic regression
ACPI: rename main.c to sleep.c
dell-laptop: move to drivers/platform/x86/ from drivers/misc/
eeepc-laptop: enable Bluetooth ACPI details
ACPI: fix ACPI_FADT_S4_RTC_WAKE comment
kprobes: check CONFIG_FREEZER instead of CONFIG_PM
PM: Fix freezer compilation if PM_SLEEP is unset
thermal fixup for broken BIOS which has invalid trip points.
ACPI: EC: Don't trust ECDT tables from ASUS
ACPI: EC: Limit workaround for ASUS notebooks even more
ACPI: thinkpad-acpi: bump up version to 0.22
ACPI: thinkpad-acpi: handle HKEY event 6030
ACPI: thinkpad-acpi: clean-up fan subdriver quirk
ACPI: thinkpad-acpi: start the event hunt season
ACPI: thinkpad-acpi: handle HKEY thermal and battery alarms
ACPI: thinkpad-acpi: clean up hotkey_notify()
ACPI: thinkpad-acpi: use killable instead of interruptible mutexes
ACPI: thinkpad-acpi: add UWB radio support
ACPI: thinkpad-acpi: preserve radio state across shutdown
ACPI: thinkpad-acpi: resume with radios disabled
...
James Bottomley [Thu, 15 Jan 2009 20:12:27 +0000 (15:12 -0500)]
ACPI PCI hotplug: harden against panic regression
ACPI hotplug panic with current git head
http://lkml.org/lkml/2009/1/10/136
Rather than reverting the entire commit that causes the crash: e8c331e963c58b83db24b7d0e39e8c07f687dbc6
"PCI hotplug: introduce functions for ACPI slot detection"
simply harden against it while the changes to
the hotplug code on this particularl machine are understood.
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com> Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org> Signed-off-by: Len Brown <len.brown@intel.com>
Although rfkill support for the EEE bluetooth device has been added to
2.6.28-rc the appropriate ACPI accessor definitions were not added, so
the support was non functional. The patch below adds the get and set
accessors and has been verified to work on an EEE 901.
Signed-off-by: Jonathan McDowell <noodles@earth.li> Acked-by: Matthew Garrett <mjg@redhat.com> Acked-by: Corentin Chary <corentincj@iksaif.net> Signed-off-by: Len Brown <len.brown@intel.com>
David Brownell [Fri, 9 Jan 2009 20:17:08 +0000 (12:17 -0800)]
ACPI: fix ACPI_FADT_S4_RTC_WAKE comment
Make the comment for ACPI_FADT_S4_RTC_WAKE match the ACPI spec;
that bit has nothing to do with status bits.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com>
Fix this by making process.o compilation depend on CONFIG_FREEZER.
Reported-by: Cheng Renquan <crquan@gmail.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@suse.cz> Signed-off-by: Len Brown <len.brown@intel.com>
Zhang Rui [Fri, 16 Jan 2009 17:53:42 +0000 (12:53 -0500)]
thermal fixup for broken BIOS which has invalid trip points.
ACPI thermal driver only re-evaluate VALID trip points.
For the broken BIOS show in
http://bugzilla.kernel.org/show_bug.cgi?id=8544
the active[0] is set to invalid at boot time
and it will not be re-evaluated again.
We can still get a single warning message at boot time.
Dhananjay Phadke [Fri, 16 Jan 2009 19:03:25 +0000 (11:03 -0800)]
netxen: include ipv6.h (fixes build failure)
Fixes a build error in absence of CONFIG_IPV6:
drivers/net/netxen/netxen_nic_main.c:1189: error: implicit declaration of function 'ipv6_hdr'
drivers/net/netxen/netxen_nic_main.c:1189: error: invalid type argument of '->'
Reported-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Dhananjay Phadke <dhananjay@netxen.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
Btrfs: fix ioctl arg size (userland incompatible change!)
Btrfs: Clear the device->running_pending flag before bailing on congestion
The structure used to send device in btrfs ioctl calls was not
properly aligned, and so 32 bit ioctls would not work properly on
64 bit kernels.
We could fix this with compat ioctls, but we're just one byte away
and it doesn't make sense at this stage to carry about the compat ioctls
forever at this stage in the project.
This patch brings the ioctl arg up to an evenly aligned 4k.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Chris Mason [Fri, 16 Jan 2009 16:58:19 +0000 (11:58 -0500)]
Btrfs: Clear the device->running_pending flag before bailing on congestion
Btrfs maintains a queue of async bio submissions so the checksumming
threads don't have to wait on get_request_wait. In order to avoid
extra wakeups, this code has a running_pending flag that is used
to tell new submissions they don't need to wake the thread.
When the threads notice congestion on a single device, they
may decide to requeue the job and move on to other devices. This
makes sure the running_pending flag is cleared before the
job is requeued.
It should help avoid IO stalls by making sure the task is woken up
when new submissions come in.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Linus Torvalds [Fri, 16 Jan 2009 16:41:09 +0000 (08:41 -0800)]
Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
serial: Add 16850 uart type support to OF uart driver
hvc_console: Remove tty->low_latency
powerpc: Get the number of SLBs from "slb-size" property
powerpc: is_hugepage_only_range() must account for both 4kB and 64kB slices
powerpc/ps3: printing fixups for l64 to ll64 conversion drivers/video
powerpc/ps3: Printing fixups for l64 to ll64 conversion drivers/scsi
powerpc/ps3: Printing fixups for l64 to ll64 conversion drivers/ps3
powerpc/ps3: Printing fixups for l64 to ll64 conversion sound/ppc
powerpc/ps3: Printing fixups for l64 to ll64 conversion drivers/char
powerpc/ps3: Printing fixups for l64 to ll64 conversion drivers/block
powerpc/ps3: Printing fixups for l64 to ll64 conversion arch/powerpc
powerpc/ps3: ps3_repository_read_mm_info() takes u64 * arguments
powerpc/ps3: clear_bit()/set_bit() operate on unsigned longs
powerpc/ps3: The lv1_ routines have u64 parameters
powerpc/ps3: Use dma_addr_t down through the stack
powerpc/ps3: set_dabr() takes an unsigned long
powerpc: Cleanup from l64 to ll64 change drivers/scsi
Linus Torvalds [Fri, 16 Jan 2009 16:40:57 +0000 (08:40 -0800)]
Merge branch 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev
* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev:
sata_fsl: Return non-zero on error in probe()
drivers/ata/pata_ali.c: s/isa_bridge/ali_isa_bridge/ to fix alpha build
libata: New driver for OCTEON SOC Compact Flash interface (v7).
libata: Add another column to the ata_timing table.
sata_via: Add VT8261 support
pata_atiixp: update port enabledness test handling
[libata] get-identity ioctl: Fix use of invalid memory pointer
Linus Torvalds [Fri, 16 Jan 2009 16:14:51 +0000 (08:14 -0800)]
Revert "PCI PM: Register power state of devices during initialization"
This reverts commit 98e6e286d7b01deb7453b717aa38ebb69d6cefc0, as Yinghai
Lu reports that it breaks kexec with at least the e1000 and e1000e
drivers. The reason is that the shutdown sequence puts the hardware
into D3 sleep, and the commit causes us to claim that it then is in D0
(running) state just because we don't understand the PM capabilities.
Which then later makes "pci_set_power_state()" not do anything, and the
device never wakes up properly and just returns 0xff to everything.
Reported-by: Yinghai Lu <yinghai@kernel.org> Acked-by: From: Rafael J. Wysocki <rjw@sisk.pl> Cc: Jesse Barnes <jesse.barnes@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andrew Morton [Thu, 15 Jan 2009 00:48:42 +0000 (16:48 -0800)]
drivers/ata/pata_ali.c: s/isa_bridge/ali_isa_bridge/ to fix alpha build
drivers/ata/pata_ali.c:44: error: static declaration of 'isa_bridge' follows non-static declaration
arch/alpha/include/asm/pci.h:274: error: previous declaration of 'isa_bridge' was here
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Jeff Garzik <jeff@garzik.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
David Daney [Fri, 16 Jan 2009 01:45:32 +0000 (17:45 -0800)]
libata: New driver for OCTEON SOC Compact Flash interface (v7).
Cavium OCTEON processor support was recently merged, so now we have
this CF driver for your consideration.
Most OCTEON variants have *no* DMA or interrupt support on the CF
interface so for these, only PIO is supported. Although if DMA is
available, we do take advantage of it.
Signed-off-by: David Daney <ddaney@caviumnetworks.com> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
David Daney [Fri, 16 Jan 2009 01:45:31 +0000 (17:45 -0800)]
libata: Add another column to the ata_timing table.
The forthcoming OCTEON SOC Compact Flash driver needs an additional
timing value that was not available in the ata_timing table. I add a
new column for dmack_hold time. The values were obtained from the
Compact Flash specification Rev 4.1.
Signed-off-by: David Daney <ddaney@caviumnetworks.com> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Tejun Heo [Fri, 16 Jan 2009 06:27:27 +0000 (15:27 +0900)]
pata_atiixp: update port enabledness test handling
Port enabledness test fits much better into init_one() instead of
pre_reset(). The reason why these tests are in pre_reset() is purely
historical at this point. Move it to init_one(). This will help
further changes.
Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Tejun Heo [Fri, 16 Jan 2009 03:11:43 +0000 (12:11 +0900)]
x86_64: initialize this_cpu_off to __per_cpu_load
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.
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
Tejun Heo [Tue, 13 Jan 2009 11:41:35 +0000 (20:41 +0900)]
x86: convert pda ops to wrappers around x86 percpu accessors
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.
Tejun Heo [Tue, 13 Jan 2009 11:41:35 +0000 (20:41 +0900)]
x86: make pda a percpu variable
[ 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.
Tejun Heo [Tue, 13 Jan 2009 11:41:35 +0000 (20:41 +0900)]
x86: merge 64 and 32 SMP percpu handling
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.