Commit Graph

1375 Commits

Author SHA1 Message Date
Jan Beulich 9032160275 x86: Unify "numa=" command line option handling
In order to be able to suppress the use of SRAT tables that
32-bit Linux can't deal with (in one case known to lead to a
non-bootable system, unless disabling ACPI altogether), move the
"numa=" option handling to common code.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Reviewed-by: Thomas Renninger <trenn@suse.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Renninger <trenn@suse.de>
LKML-Reference: <4D36B581020000780002D0FF@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-19 10:25:18 +01:00
Andrea Arcangeli 8ee53820ed thp: mmu_notifier_test_young
For GRU and EPT, we need gup-fast to set referenced bit too (this is why
it's correct to return 0 when shadow_access_mask is zero, it requires
gup-fast to set the referenced bit).  qemu-kvm access already sets the
young bit in the pte if it isn't zero-copy, if it's zero copy or a shadow
paging EPT minor fault we relay on gup-fast to signal the page is in
use...

We also need to check the young bits on the secondary pagetables for NPT
and not nested shadow mmu as the data may never get accessed again by the
primary pte.

Without this closer accuracy, we'd have to remove the heuristic that
avoids collapsing hugepages in hugepage virtual regions that have not even
a single subpage in use.

->test_young is full backwards compatible with GRU and other usages that
don't have young bits in pagetables set by the hardware and that should
nuke the secondary mmu mappings when ->clear_flush_young runs just like
EPT does.

Removing the heuristic that checks the young bit in
khugepaged/collapse_huge_page completely isn't so bad either probably but
I thought it was worth it and this makes it reliable.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13 17:32:46 -08:00
Johannes Weiner f2d6bfe9ff thp: add x86 32bit support
Add support for transparent hugepages to x86 32bit.

Share the same VM_ bitflag for VM_MAPPED_COPY.  mm/nommu.c will never
support transparent hugepages.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13 17:32:44 -08:00
Andrea Arcangeli 64cc6ae001 thp: bail out gup_fast on splitting pmd
Force gup_fast to take the slow path and block if the pmd is splitting,
not only if it's none.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13 17:32:40 -08:00
Andrea Arcangeli db3eb96f4e thp: add pmd mangling functions to x86
Add needed pmd mangling functions with symmetry with their pte
counterparts.  pmdp_splitting_flush() is the only new addition on the pmd_
methods and it's needed to serialize the VM against split_huge_page.  It
simply atomically sets the splitting bit in a similar way
pmdp_clear_flush_young atomically clears the accessed bit.
pmdp_splitting_flush() also has to flush the tlb to make it effective
against gup_fast, but it wouldn't really require to flush the tlb too.
Just the tlb flush is the simplest operation we can invoke to serialize
pmdp_splitting_flush() against gup_fast.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13 17:32:40 -08:00
Andrea Arcangeli 9180706344 thp: alter compound get_page/put_page
Alter compound get_page/put_page to keep references on subpages too, in
order to allow __split_huge_page_refcount to split an hugepage even while
subpages have been pinned by one of the get_user_pages() variants.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13 17:32:39 -08:00
Linus Torvalds e691d24e9c Merge branch 'x86-olpc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-olpc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, olpc: Speed up device tree creation during boot
  x86, olpc: Add OLPC device-tree support
  x86, of: Define irq functions to allow drivers/of/* to build on x86
2011-01-13 10:15:12 -08:00
Ingo Molnar 9adcc4a127 Merge branch 'x86/numa' into x86/urgent
Merge reason: Topic is ready for upstream.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-10 09:36:07 +01:00
Ingo Molnar 1c2a48cf65 Merge branch 'linus' into x86/apic-cleanups
Conflicts:
	arch/x86/include/asm/io_apic.h

Merge reason: Resolve the conflict, update to a more recent -rc base

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-07 14:14:15 +01:00
David Rientjes d906f0eb2f x86, numa: Fix CONFIG_DEBUG_PER_CPU_MAPS without NUMA emulation
"x86, numa: Fake node-to-cpumask for NUMA emulation" broke the
build when CONFIG_DEBUG_PER_CPU_MAPS is set and CONFIG_NUMA_EMU
is not.  This is because it is possible to map a cpu to multiple
nodes when NUMA emulation is used; the patch required a physical
node address table to find those nodes that was only available
when CONFIG_NUMA_EMU was enabled.

This extracts the common debug functionality to its own function
for CONFIG_DEBUG_PER_CPU_MAPS and uses it regardless of whether
CONFIG_NUMA_EMU is set or not.

NUMA emulation will now iterate over the set of possible nodes
for each cpu and call the new debug function whereas only the
cpu's node will be used without NUMA emulation enabled.

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <alpine.DEB.2.00.1012301053590.12995@chino.kir.corp.google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-07 14:09:34 +01:00
Linus Torvalds 4f00b901d4 Merge branch 'x86-security-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-security-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  module: Move RO/NX module protection to after ftrace module update
  x86: Resume trampoline must be executable
  x86: Add RO/NX protection for loadable kernel modules
  x86: Add NX protection for kernel data
  x86: Fix improper large page preservation
2011-01-06 11:07:33 -08:00
Linus Torvalds 37d9a8c5ea Merge branch 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: Fix included-by file reference comments
  x86, cpu: Only CPU features determine NX capabilities
  x86, cpu: Call verify_cpu during 32bit CPU startup
  x86, cpu: Clear XD_DISABLED flag on Intel to regain NX
  x86, cpu: Rename verify_cpu_64.S to verify_cpu.S
2011-01-06 10:56:02 -08:00
Linus Torvalds 017892c341 Merge branch 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: Fix APIC ID sizing bug on larger systems, clean up MAX_APICS confusion
  x86, acpi: Parse all SRAT cpu entries even above the cpu number limitation
  x86, acpi: Add MAX_LOCAL_APIC for 32bit
  x86: io_apic: Split setup_ioapic_ids_from_mpc()
  x86: io_apic: Fix CONFIG_X86_IO_APIC=n breakage
  x86: apic: Move probe_nr_irqs_gsi() into ioapic_init_mappings()
  x86: Allow platforms to force enable apic
2011-01-06 10:51:36 -08:00
Linus Torvalds 42cbd8efb0 Merge branch 'x86-amd-nb-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-amd-nb-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, cacheinfo: Cleanup L3 cache index disable support
  x86, amd-nb: Cleanup AMD northbridge caching code
  x86, amd-nb: Complete the rename of AMD NB and related code
2011-01-06 10:50:28 -08:00
Ingo Molnar bc030d6cb9 Merge commit 'v2.6.37-rc8' into x86/apic
Conflicts:
	arch/x86/include/asm/io_apic.h

Merge reason: move to a fresh -rc, resolve the conflict.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-04 09:43:42 +01:00
H. Peter Anvin d50e8fc7e3 Merge branch 'x86/apic-cleanups' into x86/numa 2010-12-29 11:36:26 -08:00
David Rientjes a387e95a49 x86, numa: Fix cpu to node mapping for sparse node ids
NUMA boot code assumes that physical node ids start at 0, but the DIMMs
that the apic id represents may not be reachable.  If this is the case,
node 0 is never online and cpus never end up getting appropriately
assigned to a node.  This causes the cpumask of all online nodes to be
empty and machines crash with kernel code assuming online nodes have
valid cpus.

The fix is to appropriately map all the address ranges for physical nodes
and ensure the cpu to node mapping function checks all possible nodes (up
to MAX_NUMNODES) instead of simply checking nodes 0-N, where N is the
number of physical nodes, for valid address ranges.

This requires no longer "compressing" the address ranges of nodes in the
physical node map from 0-N, but rather leave indices in physnodes[] to
represent the actual node id of the physical node.  Accordingly, the
topology exported by both amd_get_nodes() and acpi_get_nodes() no longer
must return the number of nodes to iterate through; all such iterations
will now be to MAX_NUMNODES.

This change also passes the end address of system RAM (which may be
different from normal operation if mem= is specified on the command line)
before the physnodes[] array is populated.  ACPI parsed nodes are
truncated to fit within the address range that respect the mem=
boundaries and even some physical nodes may become unreachable in such
cases.

When NUMA emulation does succeed, any apicid to node mapping that exists
for unreachable nodes are given default values so that proximity domains
can still be assigned.  This is important for node_distance() to
function as desired.

Signed-off-by: David Rientjes <rientjes@google.com>
LKML-Reference: <alpine.DEB.2.00.1012221702090.3701@chino.kir.corp.google.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2010-12-23 15:27:16 -08:00
David Rientjes c1c3443c9c x86, numa: Fake node-to-cpumask for NUMA emulation
It's necessary to fake the node-to-cpumask mapping so that an emulated
node ID returns a cpumask that includes all cpus that have affinity to
the memory it represents.

This is a little intrusive because it requires knowledge of the physical
topology of the system.  setup_physnodes() gives us that information, but
since NUMA emulation ends up altering the physnodes array, it's necessary
to reset it before cpus are brought online.

Accordingly, the physnodes array is moved out of init.data and into
cpuinit.data since it will be needed on cpuup callbacks.

This works regardless of whether numa=fake is used on the command line,
or the setup of the fake node succeeds or fails.  The physnodes array
always contains the physical topology of the machine if CONFIG_NUMA_EMU
is enabled and can be used to setup the correct node-to-cpumask mappings
in all cases since setup_physnodes() is called whenever the array needs
to be repopulated with the correct data.

To fake the actual mappings, numa_add_cpu() and numa_remove_cpu() are
rewritten for CONFIG_NUMA_EMU so that we first find the physical node to
which each cpu has local affinity, then iterate through all online nodes
to find the emulated nodes that have local affinity to that physical
node, and then finally map the cpu to each of those emulated nodes.

Signed-off-by: David Rientjes <rientjes@google.com>
LKML-Reference: <alpine.DEB.2.00.1012221701520.3701@chino.kir.corp.google.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2010-12-23 15:27:15 -08:00
David Rientjes f51bf3073a x86, numa: Fake apicid and pxm mappings for NUMA emulation
This patch adds the equivalent of acpi_fake_nodes() for AMD Northbridge
platforms.  The goal is to fake the apicid-to-node mappings for NUMA
emulation so the physical topology of the machine is correctly maintained
within the kernel.

This change also fakes proximity domains for both ACPI and k8 code so the
physical distance between emulated nodes is maintained via
node_distance().  This exports the correct distances via
/sys/devices/system/node/.../distance based on the underlying topology.

A new helper function, fake_physnodes(), is introduced to correctly
invoke the correct NUMA code to fake these two mappings based on the
system type.  If there is no underlying NUMA configuration, all cpus are
mapped to node 0 for local distance.

Since acpi_fake_nodes() is no longer called with CONFIG_ACPI_NUMA, it's
prototype can be removed from the header file for such a configuration.

Signed-off-by: David Rientjes <rientjes@google.com>
LKML-Reference: <alpine.DEB.2.00.1012221701360.3701@chino.kir.corp.google.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2010-12-23 15:27:14 -08:00
David Rientjes 4e76f4e67a x86, numa: Avoid compiling NUMA emulation functions without CONFIG_NUMA_EMU
Both acpi_get_nodes() and amd_get_nodes() are only necessary when
CONFIG_NUMA_EMU is enabled, so avoid compiling them when the option is
disabled.

Signed-off-by: David Rientjes <rientjes@google.com>
LKML-Reference: <alpine.DEB.2.00.1012221701210.3701@chino.kir.corp.google.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2010-12-23 15:27:12 -08:00
Yinghai Lu d3bd058826 x86, acpi: Parse all SRAT cpu entries even above the cpu number limitation
Recent Intel new system have different order in MADT, aka will list all thread0
at first, then all thread1.
But SRAT table still old order, it will list cpus in one socket all together.

If the user have compiled limited NR_CPUS or boot with nr_cpus=, could have missed
to put some cpus apic id to node mapping into apicid_to_node[].

for example for 4 sockets system with 64 cpus with nr_cpus=32 will get crash...

[    9.106288] Total of 32 processors activated (136190.88 BogoMIPS).
[    9.235021] divide error: 0000 [#1] SMP
[    9.235315] last sysfs file:
[    9.235481] CPU 1
[    9.235592] Modules linked in:
[    9.245398]
[    9.245478] Pid: 2, comm: kthreadd Not tainted 2.6.37-rc1-tip-yh-01782-ge92ef79-dirty #274      /Sun Fire x4800
[    9.265415] RIP: 0010:[<ffffffff81075a8f>]  [<ffffffff81075a8f>] select_task_rq_fair+0x4f0/0x623
...
[    9.645938] RIP  [<ffffffff81075a8f>] select_task_rq_fair+0x4f0/0x623
[    9.665356]  RSP <ffff88103f8d1c40>
[    9.665568] ---[ end trace 2296156d35fdfc87 ]---

So let just parse all cpu entries in SRAT.

Also add apicid checking with MAX_LOCAL_APIC, in case We could out of boundaries of
apicid_to_node[].

it fixes following bug too.
https://bugzilla.kernel.org/show_bug.cgi?id=22662

-v2: expand to 32bit according to hpa
   need to add MAX_LOCAL_APIC for 32bit

Reported-and-Tested-by: Wu Fengguang <fengguang.wu@intel.com>
Reported-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Tested-by: Myron Stowe <myron.stowe@hp.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4D0AD486.9020704@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2010-12-23 13:16:18 -08:00
Ingo Molnar 26e20a108c Merge commit 'v2.6.37-rc7' into x86/security 2010-12-23 09:48:41 +01:00
Andres Salomon c10d1e260f x86, olpc: Add OLPC device-tree support
Make use of PROC_DEVICETREE to export the tree, and sparc's PROMTREE code to
call into OLPC's Open Firmware to build the tree.

v5: fix buglet with root node check (introduced in v4)

v4: address some minor style issues pointed out by Grant, and explicitly cast
    negative phandle checks to s32.

v3: rename olpc_prom to olpc_dt
  - rework Kconfig entries
  - drop devtree build hook from proc, instead adding a call to x86's
    paging_init (similarly to how sparc64 does it)
  - switch allocation from using slab to alloc_bootmem.  this allows
    the DT to be built earlier during boot (during setup_arch); the
    downside is that there are some 1200 bootmem reservations that are
    done during boot.  Not ideal..
  - add a helper olpc_ofw_is_installed function to test for the
    existence and successful detection of OLPC's OFW.

Signed-off-by: Andres Salomon <dilinger@queued.net>
LKML-Reference: <20101116220952.26526a80@queued.net>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2010-12-15 17:11:30 -08:00
Yinghai Lu f115714163 x86, apic: Remove early_init_lapic_mapping()
It is almost the same as smp_register_lapic_addr(). We just need to
let smp_read_mpc() call smp_register_lapic_addr() when early==1.

Add the apic_printk to smp_register_lapic_address()

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
LKML-Reference: <4CFDF681.3030509@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-12-09 21:52:04 +01:00
Ingo Molnar 10a18d7dc0 Merge commit 'v2.6.37-rc5' into perf/core
Merge reason: Pick up the latest -rc.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-12-07 07:49:51 +01:00
Lin Ming 691513f70d x86: Resume trampoline must be executable
commit 5bd5a452(x86: Add NX protection for kernel data) marked the
trampoline area NX - which unsurprisingly breaks resume and cpu
hotplug.

Revert the portion of that commit, which touches the trampoline.

Originally-from: Lin Ming <ming.m.lin@intel.com>
LKML-Reference: <1290410581.2405.24.camel@minggr.sh.intel.com>
Cc: Matthieu Castet <castet.matthieu@free.fr>
Cc: Siarhei Liakh <sliakh.lkml@gmail.com>
Cc: Xuxian Jiang <jiang@cs.ncsu.edu>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Andi Kleen <andi@firstfloor.org>
Tested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-11-22 14:38:52 +01:00
Ingo Molnar ae51ce9061 Merge branch 'perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing into perf/core 2010-11-18 20:07:12 +01:00
Hans Rosenfeld eec1d4fa00 x86, amd-nb: Complete the rename of AMD NB and related code
Not only the naming of the files was confusing, it was even more so for
the function and variable names.

Renamed the K8 NB and NUMA stuff that is also used on other AMD
platforms. This also renames the CONFIG_K8_NUMA option to
CONFIG_AMD_NUMA and the related file k8topology_64.c to
amdtopology_64.c. No functional changes intended.

Signed-off-by: Hans Rosenfeld <hans.rosenfeld@amd.com>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2010-11-18 15:53:04 +01:00
Soeren Sandmann Pedersen 9c0729dc80 x86: Eliminate bp argument from the stack tracing routines
The various stack tracing routines take a 'bp' argument in which the
caller is supposed to provide the base pointer to use, or 0 if doesn't
have one. Since bp is garbage whenever CONFIG_FRAME_POINTER is not
defined, this means all callers in principle should either always pass
0, or be conditional on CONFIG_FRAME_POINTER.

However, there are only really three use cases for stack tracing:

(a) Trace the current task, including IRQ stack if any
(b) Trace the current task, but skip IRQ stack
(c) Trace some other task

In all cases, if CONFIG_FRAME_POINTER is not defined, bp should just
be 0.  If it _is_ defined, then

- in case (a) bp should be gotten directly from the CPU's register, so
  the caller should pass NULL for regs,

- in case (b) the caller should should pass the IRQ registers to
  dump_trace(),

- in case (c) bp should be gotten from the top of the task's stack, so
  the caller should pass NULL for regs.

Hence, the bp argument is not necessary because the combination of
task and regs is sufficient to determine an appropriate value for bp.

This patch introduces a new inline function stack_frame(task, regs)
that computes the desired bp. This function is then called from the
two versions of dump_stack().

Signed-off-by: Soren Sandmann <ssp@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arjan van de Ven <arjan@infradead.org>,
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>,
LKML-Reference: <m3oc9rop28.fsf@dhcp-100-3-82.bos.redhat.com>>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2010-11-18 14:37:34 +01:00
Matthieu Castet 5bd5a45266 x86: Add NX protection for kernel data
This patch expands functionality of CONFIG_DEBUG_RODATA to set main
(static) kernel data area as NX.

The following steps are taken to achieve this:

 1. Linker script is adjusted so .text always starts and ends on a page bound
 2. Linker script is adjusted so .rodata always start and end on a page boundary
 3. NX is set for all pages from _etext through _end in mark_rodata_ro.
 4. free_init_pages() sets released memory NX in arch/x86/mm/init.c
 5. bios rom is set to x when pcibios is used.

The results of patch application may be observed in the diff of kernel page
table dumps:

pcibios:

 -- data_nx_pt_before.txt       2009-10-13 07:48:59.000000000 -0400
 ++ data_nx_pt_after.txt        2009-10-13 07:26:46.000000000 -0400
  0x00000000-0xc0000000           3G                           pmd
  ---[ Kernel Mapping ]---
 -0xc0000000-0xc0100000           1M     RW             GLB x  pte
 +0xc0000000-0xc00a0000         640K     RW             GLB NX pte
 +0xc00a0000-0xc0100000         384K     RW             GLB x  pte
 -0xc0100000-0xc03d7000        2908K     ro             GLB x  pte
 +0xc0100000-0xc0318000        2144K     ro             GLB x  pte
 +0xc0318000-0xc03d7000         764K     ro             GLB NX pte
 -0xc03d7000-0xc0600000        2212K     RW             GLB x  pte
 +0xc03d7000-0xc0600000        2212K     RW             GLB NX pte
  0xc0600000-0xf7a00000         884M     RW         PSE GLB NX pmd
  0xf7a00000-0xf7bfe000        2040K     RW             GLB NX pte
  0xf7bfe000-0xf7c00000           8K                           pte

No pcibios:

 -- data_nx_pt_before.txt       2009-10-13 07:48:59.000000000 -0400
 ++ data_nx_pt_after.txt        2009-10-13 07:26:46.000000000 -0400
  0x00000000-0xc0000000           3G                           pmd
  ---[ Kernel Mapping ]---
 -0xc0000000-0xc0100000           1M     RW             GLB x  pte
 +0xc0000000-0xc0100000           1M     RW             GLB NX pte
 -0xc0100000-0xc03d7000        2908K     ro             GLB x  pte
 +0xc0100000-0xc0318000        2144K     ro             GLB x  pte
 +0xc0318000-0xc03d7000         764K     ro             GLB NX pte
 -0xc03d7000-0xc0600000        2212K     RW             GLB x  pte
 +0xc03d7000-0xc0600000        2212K     RW             GLB NX pte
  0xc0600000-0xf7a00000         884M     RW         PSE GLB NX pmd
  0xf7a00000-0xf7bfe000        2040K     RW             GLB NX pte
  0xf7bfe000-0xf7c00000           8K                           pte

The patch has been originally developed for Linux 2.6.34-rc2 x86 by
Siarhei Liakh <sliakh.lkml@gmail.com> and Xuxian Jiang <jiang@cs.ncsu.edu>.

 -v1:  initial patch for 2.6.30
 -v2:  patch for 2.6.31-rc7
 -v3:  moved all code into arch/x86, adjusted credits
 -v4:  fixed ifdef, removed credits from CREDITS
 -v5:  fixed an address calculation bug in mark_nxdata_nx()
 -v6:  added acked-by and PT dump diff to commit log
 -v7:  minor adjustments for -tip
 -v8:  rework with the merge of "Set first MB as RW+NX"

Signed-off-by: Siarhei Liakh <sliakh.lkml@gmail.com>
Signed-off-by: Xuxian Jiang <jiang@cs.ncsu.edu>
Signed-off-by: Matthieu CASTET <castet.matthieu@free.fr>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: James Morris <jmorris@namei.org>
Cc: Andi Kleen <ak@muc.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Dave Jones <davej@redhat.com>
Cc: Kees Cook <kees.cook@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <4CE2F82E.60601@free.fr>
[ minor cleanliness edits ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-18 12:52:04 +01:00
matthieu castet 64edc8ed5f x86: Fix improper large page preservation
This patch fixes a bug in try_preserve_large_page() which may
result in improper large page preservation and improper
application of page attributes to the memory area outside of the
original change request.

More specifically, the problem manifests itself when set_memory_*()
is called for several pages at the beginning of the large page and
try_preserve_large_page() erroneously concludes that the change can
be applied to whole large page.

The fix consists of 3 parts:

  1. Addition of "required" protection attributes in
     static_protections(), so .data and .bss can be guaranteed to
     stay "RW"

  2. static_protections() is now called for every small
     page within large page to determine compatibility of new
     protection attributes (instead of just small pages within the
     requested range).

  3. Large page can be preserved only if attribute change is
     large-page-aligned and covers whole large page.

 -v1: Try_preserve_large_page() patch for Linux 2.6.34-rc2
 -v2: Replaced pfn check with address check for kernel rw-data

Signed-off-by: Siarhei Liakh <sliakh.lkml@gmail.com>
Signed-off-by: Xuxian Jiang <jiang@cs.ncsu.edu>
Reviewed-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: James Morris <jmorris@namei.org>
Cc: Andi Kleen <ak@muc.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Dave Jones <davej@redhat.com>
Cc: Kees Cook <kees.cook@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <4CE2F7F3.8030809@free.fr>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-18 12:52:04 +01:00
Yinghai Lu 9223081f54 x86: Use online node real index in calulate_tbl_offset()
Found a NUMA system that doesn't have RAM installed at the first
socket which hangs while executing init scripts.

bisected it to:

 | commit 9329672021
 | Author: Shaohua Li <shaohua.li@intel.com>
 | Date:   Wed Oct 20 11:07:03 2010 +0800
 |
 |     x86: Spread tlb flush vector between nodes

It turns out when first socket is not online it could have cpus on
node1 tlb_offset set to bigger than NUM_INVALIDATE_TLB_VECTORS.

That could affect systems like 4 sockets, but socket 2 doesn't
have installed, sockets 3 will get too big tlb_offset.

Need to use real online node idx.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Shaohua Li <shaohua.li@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <4CDEDE59.40603@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-18 10:10:50 +01:00
Kees Cook 6036f373ea x86, cpu: Only CPU features determine NX capabilities
Fix the NX feature boot warning when NX is missing to correctly
reflect that BIOSes cannot disable NX now.

Signed-off-by: Kees Cook <kees.cook@canonical.com>
LKML-Reference: <1289414154-7829-5-git-send-email-kees.cook@canonical.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2010-11-10 15:43:15 -08:00
Rakib Mullick cf38d0ba7e x86, mm: Fix section mismatch in tlb.c
Mark tlb_cpuhp_notify as __cpuinit. It's basically a callback
function, which is called from __cpuinit init_smp_flash(). So -
it's safe.

We were warned by the following warning:

 WARNING: arch/x86/mm/built-in.o(.text+0x356d): Section mismatch
 in reference from the function tlb_cpuhp_notify() to the
 function .cpuinit.text:calculate_tlb_offset()
 The function tlb_cpuhp_notify() references
 the function __cpuinit calculate_tlb_offset().
 This is often because tlb_cpuhp_notify lacks a __cpuinit
 annotation or the annotation of calculate_tlb_offset is wrong.

Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com>
Cc: Borislav Petkov <borislav.petkov@amd.com>
Cc: Shaohua Li <shaohua.li@intel.com>
LKML-Reference: <AANLkTinWQRG=HA9uB3ad0KAqRRTinL6L_4iKgF84coph@mail.gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-01 10:09:07 +01:00
Linus Torvalds 2d10d8737c Merge branches 'x86-fixes-for-linus' and 'x86-uv-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, alternative: Call stop_machine_text_poke() on all cpus
  x86-32: Restore irq stacks NUMA-aware allocations
  x86, memblock: Fix early_node_mem with big reserved region.

* 'x86-uv-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, uv: More Westmere support on SGI UV
  x86, uv: Enable Westmere support on SGI UV
2010-10-29 18:58:00 -07:00
Yinghai Lu 419db274be x86, memblock: Fix early_node_mem with big reserved region.
Xen can reserve huge amounts of memory for pre-ballooning, but that
still shows as RAM in the e820 memory map.  early_node_mem could not
find range because of start/end adjusting, and will go through the
fallback path.  However, the fallback patch is still using
memblock_x86_find_range_node(), and it is partially top-down because
it go through active_range entries from low to high.

Let's use memblock_find_in_range instead memblock_x86_find_range_node.
So get real top down in fallback path.

We may still need to make memblock_x86_find_range_node to do overall
top_down work.

Reported-by: Jeremy Fitzhardinge <jeremy@goop.org>
Tested-by: Jeremy Fitzhardinge <jeremy@goop.org>
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4CC9A9C9.8020700@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2010-10-28 15:52:36 -07:00
Zimny Lech 61d8e11e51 Remove duplicate includes from many files
Signed-off-by: Zimny Lech <napohybelskurwysynom2010@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27 18:03:18 -07:00
Peter Zijlstra 20273941f2 mm: fix race in kunmap_atomic()
Christoph reported a nice splat which illustrated a race in the new stack
based kmap_atomic implementation.

The problem is that we pop our stack slot before we're completely done
resetting its state -- in particular clearing the PTE (sometimes that's
CONFIG_DEBUG_HIGHMEM).  If an interrupt happens before we actually clear
the PTE used for the last slot, that interrupt can reuse the slot in a
dirty state, which triggers a BUG in kmap_atomic().

Fix this by introducing kmap_atomic_idx() which reports the current slot
index without actually releasing it and use that to find the PTE and delay
the _pop() until after we're completely done.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reported-by: Christoph Hellwig <hch@infradead.org>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27 18:03:05 -07:00
Michel Lespinasse 68da336a14 x86: access_error API cleanup
access_error() already takes error_code as an argument, so there is
no need for an additional write flag.

Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Acked-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Ying Han <yinghan@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:09 -07:00
Michel Lespinasse d065bd810b mm: retry page fault when blocking on disk transfer
This change reduces mmap_sem hold times that are caused by waiting for
disk transfers when accessing file mapped VMAs.

It introduces the VM_FAULT_ALLOW_RETRY flag, which indicates that the call
site wants mmap_sem to be released if blocking on a pending disk transfer.
In that case, filemap_fault() returns the VM_FAULT_RETRY status bit and
do_page_fault() will then re-acquire mmap_sem and retry the page fault.

It is expected that the retry will hit the same page which will now be
cached, and thus it will complete with a low mmap_sem hold time.

Tests:

- microbenchmark: thread A mmaps a large file and does random read accesses
  to the mmaped area - achieves about 55 iterations/s. Thread B does
  mmap/munmap in a loop at a separate location - achieves 55 iterations/s
  before, 15000 iterations/s after.

- We are seeing related effects in some applications in house, which show
  significant performance regressions when running without this change.

[akpm@linux-foundation.org: fix warning & crash]
Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Reviewed-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Ying Han <yinghan@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: "H. Peter Anvin" <hpa@zytor.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:09 -07:00
Peter Zijlstra 3e4d3af501 mm: stack based kmap_atomic()
Keep the current interface but ignore the KM_type and use a stack based
approach.

The advantage is that we get rid of crappy code like:

	#define __KM_PTE			\
		(in_nmi() ? KM_NMI_PTE : 	\
		 in_irq() ? KM_IRQ_PTE :	\
		 KM_PTE0)

and in general can stop worrying about what context we're in and what kmap
slots might be appropriate for that.

The downside is that FRV kmap_atomic() gets more expensive.

For now we use a CPP trick suggested by Andrew:

  #define kmap_atomic(page, args...) __kmap_atomic(page)

to avoid having to touch all kmap_atomic() users in a single patch.

[ not compiled on:
  - mn10300: the arch doesn't actually build with highmem to begin with ]

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix up drivers/gpu/drm/i915/intel_overlay.c]
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Miller <davem@davemloft.net>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dave Airlie <airlied@linux.ie>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:08 -07:00
Linus Torvalds f1ebdd60cc Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6
* 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6: (22 commits)
  Add _addr_lsb field to ia64 siginfo
  Fix migration.c compilation on s390
  HWPOISON: Remove retry loop for try_to_unmap
  HWPOISON: Turn addr_valid from bitfield into char
  HWPOISON: Disable DEBUG by default
  HWPOISON: Convert pr_debugs to pr_info
  HWPOISON: Improve comments in memory-failure.c
  x86: HWPOISON: Report correct address granuality for huge hwpoison faults
  Encode huge page size for VM_FAULT_HWPOISON errors
  Fix build error with !CONFIG_MIGRATION
  hugepage: move is_hugepage_on_freelist inside ifdef to avoid warning
  Clean up __page_set_anon_rmap
  HWPOISON, hugetlb: fix unpoison for hugepage
  HWPOISON, hugetlb: soft offlining for hugepage
  HWPOSION, hugetlb: recover from free hugepage error when !MF_COUNT_INCREASED
  hugetlb: move refcounting in hugepage allocation inside hugetlb_lock
  HWPOISON, hugetlb: add free check to dequeue_hwpoison_huge_page()
  hugetlb: hugepage migration core
  hugetlb: redefine hugepage copy functions
  hugetlb: add allocate function for hugepage migration
  ...
2010-10-26 10:13:10 -07:00
Linus Torvalds 10f2a2b0f6 Merge branch 'x86-trampoline-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-trampoline-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86-32, mm: Add an initial page table for core bootstrapping
2010-10-22 20:37:50 -07:00
Andi Kleen 46e387bbd8 Merge branch 'hwpoison-hugepages' into hwpoison
Conflicts:
	mm/memory-failure.c
2010-10-22 17:40:48 +02:00
Linus Torvalds 3044100e58 Merge branch 'core-memblock-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-memblock-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (74 commits)
  x86-64: Only set max_pfn_mapped to 512 MiB if we enter via head_64.S
  xen: Cope with unmapped pages when initializing kernel pagetable
  memblock, bootmem: Round pfn properly for memory and reserved regions
  memblock: Annotate memblock functions with __init_memblock
  memblock: Allow memblock_init to be called early
  memblock/arm: Fix memblock_region_is_memory() typo
  x86, memblock: Remove __memblock_x86_find_in_range_size()
  memblock: Fix wraparound in find_region()
  x86-32, memblock: Make add_highpages honor early reserved ranges
  x86, memblock: Fix crashkernel allocation
  arm, memblock: Fix the sparsemem build
  memblock: Fix section mismatch warnings
  powerpc, memblock: Fix memblock API change fallout
  memblock, microblaze: Fix memblock API change fallout
  x86: Remove old bootmem code
  x86, memblock: Use memblock_memory_size()/memblock_free_memory_size() to get correct dma_reserve
  x86: Remove not used early_res code
  x86, memblock: Replace e820_/_early string with memblock_
  x86: Use memblock to replace early_res
  x86, memblock: Use memblock_debug to control debug message print out
  ...

Fix up trivial conflicts in arch/x86/kernel/setup.c and kernel/Makefile
2010-10-21 18:52:11 -07:00
Linus Torvalds 709d9f54cc Merge branch 'x86-vmware-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-vmware-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, paravirt: Remove alloc_pmd_clone hook, only used by VMI
  x86, vmware: Remove deprecated VMI kernel support

Fix up trivial #include conflict in arch/x86/kernel/smpboot.c
2010-10-21 13:53:24 -07:00
Linus Torvalds c3b86a2942 Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86-32, percpu: Correct the ordering of the percpu readmostly section
  x86, mm: Enable ARCH_DMA_ADDR_T_64BIT with X86_64 || HIGHMEM64G
  x86: Spread tlb flush vector between nodes
  percpu: Introduce a read-mostly percpu API
  x86, mm: Fix incorrect data type in vmalloc_sync_all()
  x86, mm: Hold mm->page_table_lock while doing vmalloc_sync
  x86, mm: Fix bogus whitespace in sync_global_pgds()
  x86-32: Fix sparse warning for the __PHYSICAL_MASK calculation
  x86, mm: Add RESERVE_BRK_ARRAY() helper
  mm, x86: Saving vmcore with non-lazy freeing of vmas
  x86, kdump: Change copy_oldmem_page() to use cached addressing
  x86, mm: fix uninitialized addr in kernel_physical_mapping_init()
  x86, kmemcheck: Remove double test
  x86, mm: Make spurious_fault check explicitly check the PRESENT bit
  x86-64, mem: Update all PGDs for direct mapping and vmemmap mapping changes
  x86, mm: Separate x86_64 vmalloc_sync_all() into separate functions
  x86, mm: Avoid unnecessary TLB flush
2010-10-21 13:47:29 -07:00
Linus Torvalds d60a2793ba Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: Remove stale pmtimer_64.c
  x86, cleanups: Use clear_page/copy_page rather than memset/memcpy
  x86: Remove unnecessary #ifdef ACPI/X86_IO_ACPI
  x86, cleanup: Remove obsolete boot_cpu_id variable
2010-10-21 13:18:06 -07:00
Linus Torvalds 2f0384e5fc Merge branch 'x86-amd-nb-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-amd-nb-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, amd_nb: Enable GART support for AMD family 0x15 CPUs
  x86, amd: Use compute unit information to determine thread siblings
  x86, amd: Extract compute unit information for AMD CPUs
  x86, amd: Add support for CPUID topology extension of AMD CPUs
  x86, nmi: Support NMI watchdog on newer AMD CPU families
  x86, mtrr: Assume SYS_CFG[Tom2ForceMemTypeWB] exists on all future AMD CPUs
  x86, k8: Rename k8.[ch] to amd_nb.[ch] and CONFIG_K8_NB to CONFIG_AMD_NB
  x86, k8-gart: Decouple handling of garts and northbridges
  x86, cacheinfo: Fix dependency of AMD L3 CID
  x86, kvm: add new AMD SVM feature bits
  x86, cpu: Fix allowed CPUID bits for KVM guests
  x86, cpu: Update AMD CPUID feature bits
  x86, cpu: Fix renamed, not-yet-shipping AMD CPUID feature bit
  x86, AMD: Remove needless CPU family check (for L3 cache info)
  x86, tsc: Remove CPU frequency calibration on AMD
2010-10-21 13:01:08 -07:00
Linus Torvalds 5d70f79b5e Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (163 commits)
  tracing: Fix compile issue for trace_sched_wakeup.c
  [S390] hardirq: remove pointless header file includes
  [IA64] Move local_softirq_pending() definition
  perf, powerpc: Fix power_pmu_event_init to not use event->ctx
  ftrace: Remove recursion between recordmcount and scripts/mod/empty
  jump_label: Add COND_STMT(), reducer wrappery
  perf: Optimize sw events
  perf: Use jump_labels to optimize the scheduler hooks
  jump_label: Add atomic_t interface
  jump_label: Use more consistent naming
  perf, hw_breakpoint: Fix crash in hw_breakpoint creation
  perf: Find task before event alloc
  perf: Fix task refcount bugs
  perf: Fix group moving
  irq_work: Add generic hardirq context callbacks
  perf_events: Fix transaction recovery in group_sched_in()
  perf_events: Fix bogus AMD64 generic TLB events
  perf_events: Fix bogus context time tracking
  tracing: Remove parent recording in latency tracer graph options
  tracing: Use one prologue for the preempt irqs off tracer function tracers
  ...
2010-10-21 12:54:49 -07:00