Commit Graph

398 Commits

Author SHA1 Message Date
Linus Torvalds
ffa009c366 Merge git://git.infradead.org/iommu-2.6
* git://git.infradead.org/iommu-2.6:
  drivers/pci/intr_remapping.c: include acpi.h
  intel-iommu: Fix oops in device_to_iommu() when devices not found.
  intel-iommu: Handle PCI domains appropriately.
  intel-iommu: Fix device-to-iommu mapping for PCI-PCI bridges.
  x2apic/intr-remap: decouple interrupt remapping from x2apic
  x86, dmar: check if it's initialized before disable queue invalidation
  intel-iommu: set compatibility format interrupt
  Intel IOMMU Suspend/Resume Support - Interrupt Remapping
  Intel IOMMU Suspend/Resume Support - Queued Invalidation
  Intel IOMMU Suspend/Resume Support - DMAR
  intel-iommu: Add for_each_iommu() and for_each_active_iommu() macros
2009-04-06 14:26:05 -07:00
Linus Torvalds
714f83d5d9 Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (413 commits)
  tracing, net: fix net tree and tracing tree merge interaction
  tracing, powerpc: fix powerpc tree and tracing tree interaction
  ring-buffer: do not remove reader page from list on ring buffer free
  function-graph: allow unregistering twice
  trace: make argument 'mem' of trace_seq_putmem() const
  tracing: add missing 'extern' keywords to trace_output.h
  tracing: provide trace_seq_reserve()
  blktrace: print out BLK_TN_MESSAGE properly
  blktrace: extract duplidate code
  blktrace: fix memory leak when freeing struct blk_io_trace
  blktrace: fix blk_probes_ref chaos
  blktrace: make classic output more classic
  blktrace: fix off-by-one bug
  blktrace: fix the original blktrace
  blktrace: fix a race when creating blk_tree_root in debugfs
  blktrace: fix timestamp in binary output
  tracing, Text Edit Lock: cleanup
  tracing: filter fix for TRACE_EVENT_FORMAT events
  ftrace: Using FTRACE_WARN_ON() to check "freed record" in ftrace_release()
  x86: kretprobe-booster interrupt emulation code fix
  ...

Fix up trivial conflicts in
 arch/parisc/include/asm/ftrace.h
 include/linux/memory.h
 kernel/extable.c
 kernel/module.c
2009-04-05 11:04:19 -07:00
Han, Weidong
d0b03bd1c6 x2apic/intr-remap: decouple interrupt remapping from x2apic
interrupt remapping must be enabled before enabling x2apic, but
interrupt remapping doesn't depend on x2apic, it can be used
separately. Enable interrupt remapping in init_dmars even x2apic
is not supported.

[dwmw2: Update Kconfig accordingly, fix build with INTR_REMAP && !X2APIC]

Signed-off-by: Weidong Han <weidong.han@intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2009-04-04 10:42:28 +01:00
Linus Torvalds
811158b147 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (28 commits)
  trivial: Update my email address
  trivial: NULL noise: drivers/mtd/tests/mtd_*test.c
  trivial: NULL noise: drivers/media/dvb/frontends/drx397xD_fw.h
  trivial: Fix misspelling of "Celsius".
  trivial: remove unused variable 'path' in alloc_file()
  trivial: fix a pdlfush -> pdflush typo in comment
  trivial: jbd header comment typo fix for JBD_PARANOID_IOFAIL
  trivial: wusb: Storage class should be before const qualifier
  trivial: drivers/char/bsr.c: Storage class should be before const qualifier
  trivial: h8300: Storage class should be before const qualifier
  trivial: fix where cgroup documentation is not correctly referred to
  trivial: Give the right path in Documentation example
  trivial: MTD: remove EOL from MODULE_DESCRIPTION
  trivial: Fix typo in bio_split()'s documentation
  trivial: PWM: fix of #endif comment
  trivial: fix typos/grammar errors in Kconfig texts
  trivial: Fix misspelling of firmware
  trivial: cgroups: documentation typo and spelling corrections
  trivial: Update contact info for Jochen Hein
  trivial: fix typo "resgister" -> "register"
  ...
2009-04-03 15:24:35 -07:00
Linus Torvalds
ca1ee219c0 Merge git://git.infradead.org/iommu-2.6
* git://git.infradead.org/iommu-2.6:
  intel-iommu: Fix address wrap on 32-bit kernel.
  intel-iommu: Enable DMAR on 32-bit kernel.
  intel-iommu: fix PCI device detach from virtual machine
  intel-iommu: VT-d page table to support snooping control bit
  iommu: Add domain_has_cap iommu_ops
  intel-iommu: Snooping control support

Fixed trivial conflicts in arch/x86/Kconfig and drivers/pci/intel-iommu.c
2009-04-03 10:36:57 -07:00
Ingo Molnar
8302294f43 Merge branch 'tracing/core-v2' into tracing-for-linus
Conflicts:
	include/linux/slub_def.h
	lib/Kconfig.debug
	mm/slob.c
	mm/slub.c
2009-04-02 00:49:02 +02:00
Akinobu Mita
6a11f75b6a generic debug pagealloc
CONFIG_DEBUG_PAGEALLOC is now supported by x86, powerpc, sparc64, and
s390.  This patch implements it for the rest of the architectures by
filling the pages with poison byte patterns after free_pages() and
verifying the poison patterns before alloc_pages().

This generic one cannot detect invalid page accesses immediately but
invalid read access may cause invalid dereference by poisoned memory and
invalid write access can be detected after a long delay.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.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>
2009-04-01 08:59:13 -07:00
Linus Torvalds
712b0006bf Merge branch 'iommu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'iommu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (60 commits)
  dma-debug: make memory range checks more consistent
  dma-debug: warn of unmapping an invalid dma address
  dma-debug: fix dma_debug_add_bus() definition for !CONFIG_DMA_API_DEBUG
  dma-debug/x86: register pci bus for dma-debug leak detection
  dma-debug: add a check dma memory leaks
  dma-debug: add checks for kernel text and rodata
  dma-debug: print stacktrace of mapping path on unmap error
  dma-debug: Documentation update
  dma-debug: x86 architecture bindings
  dma-debug: add function to dump dma mappings
  dma-debug: add checks for sync_single_sg_*
  dma-debug: add checks for sync_single_range_*
  dma-debug: add checks for sync_single_*
  dma-debug: add checking for [alloc|free]_coherent
  dma-debug: add add checking for map/unmap_sg
  dma-debug: add checking for map/unmap_page/single
  dma-debug: add core checking functions
  dma-debug: add debugfs interface
  dma-debug: add kernel command line parameters
  dma-debug: add initialization code
  ...

Fix trivial conflicts due to whitespace changes in arch/x86/kernel/pci-nommu.c
2009-03-30 13:41:00 -07:00
Matt LaPlante
692105b8ac trivial: fix typos/grammar errors in Kconfig texts
Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2009-03-30 15:22:01 +02:00
Ingo Molnar
b0d44c0dbb Merge branch 'linus' into core/iommu
Conflicts:
	arch/x86/Kconfig
2009-03-28 23:05:50 +01:00
Ingo Molnar
6e15cf0486 Merge branch 'core/percpu' into percpu-cpumask-x86-for-linus-2
Conflicts:
	arch/parisc/kernel/irq.c
	arch/x86/include/asm/fixmap_64.h
	arch/x86/include/asm/setup.h
	kernel/irq/handle.c

Semantic merge:
        arch/x86/include/asm/fixmap.h

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-27 17:28:43 +01:00
Thomas Gleixner
fc2869f6a1 x86: disable __do_IRQ support
Impact: disable unused code

x86 is fully converted to flow handlers. No need to keep the
deprecated __do_IRQ() support active.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-26 16:36:08 +01:00
David Woodhouse
4cf2e75d0b intel-iommu: Enable DMAR on 32-bit kernel.
If we fix a few highmem-related thinkos and a couple of printk format
warnings, the Intel IOMMU driver works fine in a 32-bit kernel.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2009-03-25 16:00:41 +00:00
Joerg Roedel
2118d0c548 dma-debug: x86 architecture bindings
Impact: make use of DMA-API debugging code in x86

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
2009-03-17 12:56:46 +01:00
Ingo Molnar
0ca0f16fd1 Merge branches 'x86/apic', 'x86/asm', 'x86/cleanups', 'x86/debug', 'x86/kconfig', 'x86/mm', 'x86/ptrace', 'x86/setup' and 'x86/urgent'; commit 'v2.6.29-rc8' into x86/core 2009-03-14 16:25:40 +01:00
Ingo Molnar
62395efdb0 Merge branch 'x86/asm' into tracing/syscalls
We need the wider TIF work-mask checks in entry_32.S.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-14 09:44:08 +01:00
Ingo Molnar
0634023562 Merge branch 'x86/core' into x86/kconfig 2009-03-13 17:08:30 +01:00
Thomas Gleixner
f9a36fa541 x86: disable __do_IRQ support
Impact: disable unused code

x86 is fully converted to flow handlers. No need to keep the
deprecated __do_IRQ() support active.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-03-13 16:46:37 +01:00
Frederic Weisbecker
1b3fa2ce64 tracing/x86: basic implementation of syscall tracing for x86
Provide the x86 trace callbacks to trace syscalls.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <1236401580-5758-3-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-13 06:25:44 +01:00
Jan Beulich
46d50c98d9 x86, 32-bit: also limit NODES_HIGH_SHIFT here
Impact: configuration bug fix

Just like for x86-64, the range of widths valid for NODE_SHIFT is not
unbounded. The upper bound 64-bit uses is definitely also an upper
bound for 32-bit.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
LKML-Reference: <49B90F12.76E4.0078.0@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-13 02:37:17 +01:00
Ingo Molnar
a98fe7f342 Merge branches 'x86/asm', 'x86/debug', 'x86/mm', 'x86/setup', 'x86/urgent' and 'linus' into x86/core 2009-03-12 11:50:15 +01:00
Huang Ying
fee7b0d84c x86, kexec: x86_64: add kexec jump support for x86_64
Impact: New major feature

This patch add kexec jump support for x86_64. More information about
kexec jump can be found in corresponding x86_32 support patch.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-03-10 18:13:25 -07:00
Jaswinder Singh Rajput
9b779edf4b x86: cpu architecture debug code
Introduce:

 cat /sys/kernel/debug/x86/cpu/*

for Intel and AMD processors to view / debug the state of each CPU.

By using this we can debug whole range of registers and other
cpu information for debugging purpose and monitor how things
are changing.

This can be useful for developers as well as for users.

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
LKML-Reference: <1236701373.3387.4.camel@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-10 18:39:45 +01:00
Ingo Molnar
f0ef039851 Merge branch 'x86/core' into tracing/textedit
Conflicts:
	arch/x86/Kconfig
	block/blktrace.c
	kernel/irq/handle.c

Semantic conflict:
	kernel/trace/blktrace.c

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 16:45:01 +01:00
Ingo Molnar
caab36b593 Merge branch 'x86/mce2' into x86/core 2009-03-05 21:49:25 +01:00
H. Peter Anvin
2e22ea7cea Merge branch 'x86/core' into x86/mce2 2009-03-03 21:05:42 -08:00
Ingo Molnar
91d75e209b Merge branch 'x86/core' into core/percpu 2009-03-04 02:29:19 +01:00
Ingo Molnar
8b0e5860cb Merge branches 'x86/apic', 'x86/cpu', 'x86/fixmap', 'x86/mm', 'x86/sched', 'x86/setup-lzma', 'x86/signal' and 'x86/urgent' into x86/core 2009-03-04 02:22:31 +01:00
Ingo Molnar
fdfa66ab45 Merge branches 'tracing/ftrace', 'tracing/mmiotrace' and 'linus' into tracing/core 2009-03-02 22:37:35 +01:00
Ingo Molnar
55f2b78995 Merge branch 'x86/urgent' into x86/pat 2009-03-01 12:47:58 +01:00
Kyle McMartin
f6be37fdc6 x86: enable DMAR by default
Now that the obvious bugs have been worked out, specifically
the iwlagn issue, and the write buffer errata, DMAR should be safe
to turn back on by default. (We've had it on since those patches were
first written a few weeks ago, without any noticeable bug reports
(most have been due to the dma-api debug patchset.))

Signed-off-by: Kyle McMartin <kyle@redhat.com>
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-26 20:59:47 +01:00
H. Peter Anvin
638bee71c8 Merge branch 'x86/core' into x86/mce2 2009-02-24 16:11:51 -08:00
Andi Kleen
b276268631 x86, mce, cmci: factor out threshold interrupt handler
Impact: cleanup; preparation for feature

The mce_amd_64 code has an own private MC threshold vector with an own
interrupt handler. Since Intel needs a similar handler
it makes sense to share the vector because both can not
be active at the same time.

I factored the common APIC handler code into a separate file which can
be used by both the Intel or AMD MC code.

This is needed for the next patch which adds an Intel specific
CMCI handler.

This patch should be a nop for AMD, it just moves some code
around.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-02-24 13:24:42 -08:00
Ingo Molnar
0edcf8d692 Merge branch 'tj-percpu' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc into core/percpu
Conflicts:
	arch/x86/include/asm/pgtable.h
2009-02-24 21:52:45 +01:00
Tejun Heo
c132937556 bootmem: clean up arch-specific bootmem wrapping
Impact: cleaner and consistent bootmem wrapping

By setting CONFIG_HAVE_ARCH_BOOTMEM_NODE, archs can define
arch-specific wrappers for bootmem allocation.  However, this is done
a bit strangely in that only the high level convenience macros can be
changed while lower level, but still exported, interface functions
can't be wrapped.  This not only is messy but also leads to strange
situation where alloc_bootmem() does what the arch wants it to do but
the equivalent __alloc_bootmem() call doesn't although they should be
able to be used interchangeably.

This patch updates bootmem such that archs can override / wrap the
backend function - alloc_bootmem_core() instead of the highlevel
interface functions to allow simpler and consistent wrapping.  Also,
HAVE_ARCH_BOOTMEM_NODE is renamed to HAVE_ARCH_BOOTMEM.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Johannes Weiner <hannes@saeurebad.de>
2009-02-24 11:57:20 +09:00
Ingo Molnar
965c7ecaf2 x86: remove the Voyager 32-bit subarch
Impact: remove unused/broken code

The Voyager subarch last built successfully on the v2.6.26 kernel
and has been stale since then and does not build on the v2.6.27,
v2.6.28 and v2.6.29-rc5 kernels.

No actual users beyond the maintainer reported this breakage.
Patches were sent and most of the fixes were accepted but the
discussion around how to do a few remaining issues cleanly
fizzled out with no resolution and the code remained broken.

In the v2.6.30 x86 tree development cycle 32-bit subarch support
has been reworked and removed - and the Voyager code, beyond the
build problems already known, needs serious and significant
changes and probably a rewrite to support it.

CONFIG_X86_VOYAGER has been marked BROKEN then. The maintainer has
been notified but no patches have been sent so far to fix it.

While all other subarchs have been converted to the new scheme,
voyager is still broken. We'd prefer to receive patches which
clean up the current situation in a constructive way, but even in
case of removal there is no obstacle to add that support back
after the issues have been sorted out in a mutually acceptable
fashion.

So remove this inactive code for now.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-23 00:54:01 +01:00
Ravikiran G Thirumalai
8425091ff8 x86: improve the help text of X86_EXTENDED_PLATFORM
Change the CONFIG_X86_EXTENDED_PLATFORM help text to display the
32bit/64bit extended platform list. This is as suggested by Ingo.

Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Cc: shai@scalex86.org
Cc: "Benzi Galili (Benzi@ScaleMP.com)" <benzi@scalemp.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-22 20:21:31 +01:00
Tejun Heo
11124411aa x86: convert to the new dynamic percpu allocator
Impact: use new dynamic allocator, unified access to static/dynamic
        percpu memory

Convert to the new dynamic percpu allocator.

* implement populate_extra_pte() for both 32 and 64
* update setup_per_cpu_areas() to use pcpu_setup_static()
* define __addr_to_pcpu_ptr() and __pcpu_ptr_to_addr()
* define config HAVE_DYNAMIC_PER_CPU_AREA

Signed-off-by: Tejun Heo <tj@kernel.org>
2009-02-20 16:29:09 +09:00
Ingo Molnar
7d01d32d3b x86, apic: fix build fallout of genapic changes
- make oprofile build
- select X86_X2APIC from X86_UV - it relies on it
- export genapic for oprofile modular build

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-17 13:13:25 +01:00
Yinghai Lu
06cd9a7dc8 x86: add x2apic config
Impact: cleanup

so could deselect x2apic
and INTR_REMAP will select x2apic

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-17 12:22:20 +01:00
Ingo Molnar
1c511f740f Merge branches 'tracing/ftrace', 'tracing/ring-buffer', 'tracing/sysprof', 'tracing/urgent' and 'linus' into tracing/core 2009-02-13 10:25:18 +01:00
Ingo Molnar
ab639f3593 Merge branch 'core/percpu' into x86/core 2009-02-13 09:45:09 +01:00
Ingo Molnar
17993b49b1 x86: make hibernation always-possible
This commit:

  aced3ce: x86/Voyager: remove HIBERNATION Kconfig quirk

Made hibernation only available on UP - instead of making it available
on all of x86. Fix it.

Reported-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-11 17:20:51 +01:00
Ravikiran G Thirumalai
c5c606d9dc x86: cleanup, rename CONFIG_X86_NON_STANDARD to CONFIG_X86_EXTENDED_PLATFORM
Patch to rename the CONFIG_X86_NON_STANDARD to CONFIG_X86_EXTENDED_PLATFORM.

The new name represents the subarches better. Also, default this to 'y'
so that many of the sub architectures that were not easily visible now
become visible.

Also re-organize the extended architecture platform and non standard
platform list alphabetically as suggested by Ingo.

Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Shai Fultheim <shai@scalex86.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-11 14:17:40 +01:00
Tejun Heo
60a5317ff0 x86: implement x86_32 stack protector
Impact: stack protector for x86_32

Implement stack protector for x86_32.  GDT entry 28 is used for it.
It's set to point to stack_canary-20 and have the length of 24 bytes.
CONFIG_CC_STACKPROTECTOR turns off CONFIG_X86_32_LAZY_GS and sets %gs
to the stack canary segment on entry.  As %gs is otherwise unused by
the kernel, the canary can be anywhere.  It's defined as a percpu
variable.

x86_32 exception handlers take register frame on stack directly as
struct pt_regs.  With -fstack-protector turned on, gcc copies the
whole structure after the stack canary and (of course) doesn't copy
back on return thus losing all changed.  For now, -fno-stack-protector
is added to all files which contain those functions.  We definitely
need something better.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-10 00:42:01 +01:00
Tejun Heo
ccbeed3a05 x86: make lazy %gs optional on x86_32
Impact: pt_regs changed, lazy gs handling made optional, add slight
        overhead to SAVE_ALL, simplifies error_code path a bit

On x86_32, %gs hasn't been used by kernel and handled lazily.  pt_regs
doesn't have place for it and gs is saved/loaded only when necessary.
In preparation for stack protector support, this patch makes lazy %gs
handling optional by doing the followings.

* Add CONFIG_X86_32_LAZY_GS and place for gs in pt_regs.

* Save and restore %gs along with other registers in entry_32.S unless
  LAZY_GS.  Note that this unfortunately adds "pushl $0" on SAVE_ALL
  even when LAZY_GS.  However, it adds no overhead to common exit path
  and simplifies entry path with error code.

* Define different user_gs accessors depending on LAZY_GS and add
  lazy_save_gs() and lazy_load_gs() which are noop if !LAZY_GS.  The
  lazy_*_gs() ops are used to save, load and clear %gs lazily.

* Define ELF_CORE_COPY_KERNEL_REGS() which always read %gs directly.

xen and lguest changes need to be verified.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-10 00:42:00 +01:00
Ingo Molnar
92e2d50846 Merge branch 'x86/urgent' into core/percpu
Conflicts:
	arch/x86/kernel/acpi/boot.c
2009-02-10 00:41:02 +01:00
Steven Rostedt
9a5fd90227 ftrace: change function graph tracer to use new in_nmi
The function graph tracer piggy backed onto the dynamic ftracer
to use the in_nmi custom code for dynamic tracing. The problem
was (as Andrew Morton pointed out) it really only wanted to bail
out if the context of the current CPU was in NMI context. But the
dynamic ftrace in_nmi custom code was true if _any_ CPU happened
to be in NMI context.

Now that we have a generic in_nmi interface, this patch changes
the function graph code to use it instead of the dynamic ftarce
custom code.

Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-07 20:02:55 -05:00
Steven Rostedt
78d904b46a ring-buffer: add NMI protection for spinlocks
Impact: prevent deadlock in NMI

The ring buffers are not yet totally lockless with writing to
the buffer. When a writer crosses a page, it grabs a per cpu spinlock
to protect against a reader. The spinlocks taken by a writer are not
to protect against other writers, since a writer can only write to
its own per cpu buffer. The spinlocks protect against readers that
can touch any cpu buffer. The writers are made to be reentrant
with the spinlocks disabling interrupts.

The problem arises when an NMI writes to the buffer, and that write
crosses a page boundary. If it grabs a spinlock, it can be racing
with another writer (since disabling interrupts does not protect
against NMIs) or with a reader on the same CPU. Luckily, most of the
users are not reentrant and protects against this issue. But if a
user of the ring buffer becomes reentrant (which is what the ring
buffers do allow), if the NMI also writes to the ring buffer then
we risk the chance of a deadlock.

This patch moves the ftrace_nmi_enter called by nmi_enter() to the
ring buffer code. It replaces the current ftrace_nmi_enter that is
used by arch specific code to arch_ftrace_nmi_enter and updates
the Kconfig to handle it.

When an NMI is called, it will set a per cpu variable in the ring buffer
code and will clear it when the NMI exits. If a write to the ring buffer
crosses page boundaries inside an NMI, a trylock is used on the spin
lock instead. If the spinlock fails to be acquired, then the entry
is discarded.

This bug appeared in the ftrace work in the RT tree, where event tracing
is reentrant. This workaround solved the deadlocks that appeared there.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-07 20:00:17 -05:00
Ingo Molnar
8f9ca475c9 x86: clean up arch/x86/Kconfig*
- Consistent alignment of help text
- Use the ---help--- keyword everywhere consistently as a visual separator
- fix whitespace mismatches

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-05 22:30:20 +01:00