This patch adds new syscalls to x86_32
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, UV: Initialize the broadcast assist unit base destination node id properly
x86, numa: Fix numa_emulation code with memory-less node0
x86, build: Make sure mkpiggy fails on read error
Return 0 on failure. This will cause the initialization of the driver
to fail and prevent the driver from loading if the BIOS cannot handle
the PCC interface command to "get frequency". Otherwise, the driver
will load and display a very high value like "4294967274" (which is
actually -EINVAL) for frequency:
# cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq
4294967274
Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
CC: stable@kernel.org
Signed-off-by: Dave Jones <davej@redhat.com>
The BAU's initialization of the broadcast description header is
lacking the coherence domain (high bits) in the nasid. This
causes a catastrophic system failure when running on a system
with multiple coherence domains.
Signed-off-by: Cliff Wickman <cpw@sgi.com>
LKML-Reference: <E1PxKBB-0005F0-3U@eag09.americas.sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This crash happens on a system that does not have RAM on node0.
When numa_emulation is compiled in, and:
1. we boot the system without numa=fake...
2. or we boot the system with numa=fake=128 to make emulation fail
we will get:
[ 0.076025] ------------[ cut here ]------------
[ 0.080004] kernel BUG at arch/x86/mm/numa_64.c:788!
[ 0.080004] invalid opcode: 0000 [#1] SMP
[...]
need to use early_cpu_to_node() directly, because cpu_to_apicid
and apicid_to_node will return node0 that is not onlined.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: David Rientjes <rientjes@google.com>
LKML-Reference: <4D6ECF72.5010308@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'devicetree/merge' of git://git.secretlab.ca/git/linux-2.6:
of/promtree: allow DT device matching by fixing 'name' brokenness (v5)
x86: OLPC: have prom_early_alloc BUG rather than return NULL
of/flattree: Drop an uninteresting message to pr_debug level
of: Add missing of_address.h to xilinx ehci driver
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq:
[CPUFREQ] p4-clockmod: print EST-capable warning message only once
[CPUFREQ] fix BUG on cpufreq policy init failure
[CPUFREQ] Fix another notifier leak in powernow-k8.
[CPUFREQ] Missing "unregister_cpu_notifier" in powernow-k8.c
..similar to what sparc's prom_early_alloc does.
Signed-off-by: Andres Salomon <dilinger@queued.net>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Ensure build doesn't silently continue despite read failure,
addressing a warning due to the unchecked call.
Signed-off-by: Daniel J Blueman <daniel.blueman@gmail.com>
LKML-Reference: <AANLkTimxxTMU3=4ry-_zbY6v1xiDi+hW9y1RegTr8vLK@mail.gmail.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Do the notifier registration later, so we don't have to worry
about freeing it if we fail the msr allocation.
Signed-off-by: Dave Jones <davej@redhat.com>
It appears that when powernow-k8 finds that
No compatible ACPI _PSS objects found.
and suggests
Try again with latest BIOS.
it fails the module load, but does not unregister the cpu_notifier that was
registered in powernowk8_init
This ends up leaving freed memory on the cpu notifier list for some other
poor module (e.g. md/raid5) to come along and trip over.
The following might be a partial fix, but I suspect there is probably other
clean-up that is needed.
( https://bugzilla.novell.com/show_bug.cgi?id=655215 has full dmesg traces).
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Neil Brown <neilb@suse.de>
A customer of ours, complained that when setting the reset
vector back to 0, it trashed other data and hung their box.
They noticed when only 4 bytes were set to 0 instead of 8,
everything worked correctly.
Mathew pointed out:
|
| We're supposed to be resetting trampoline_phys_low and
| trampoline_phys_high here, which are two 16-bit values.
| Writing 64 bits is definitely going to overwrite space
| that we're not supposed to be touching.
|
So limit the area modified to u32.
Signed-off-by: Don Zickus <dzickus@redhat.com>
Acked-by: Matthew Garrett <mjg@redhat.com>
Cc: <stable@kernel.org>
LKML-Reference: <1297139100-424-1-git-send-email-dzickus@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86 quirk: Fix polarity for IRQ0 pin2 override on SB800 systems
x86/mrst: Fix apb timer rating when lapic timer is used
x86: Fix reboot problem on VersaLogic Menlow boards
On some SB800 systems polarity for IOAPIC pin2 is wrongly
specified as low active by BIOS. This caused system hangs after
resume from S3 when HPET was used in one-shot mode on such
systems because a timer interrupt was missed (HPET signal is
high active).
For more details see:
http://marc.info/?l=linux-kernel&m=129623757413868
Tested-by: Manoj Iyer <manoj.iyer@canonical.com>
Tested-by: Andre Przywara <andre.przywara@amd.com>
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Borislav Petkov <borislav.petkov@amd.com>
Cc: stable@kernel.org # 37.x, 32.x
LKML-Reference: <20110224145346.GD3658@alberich.amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Need to adjust the clockevent device rating for the structure
that will be registered with clockevent system instead of the
temporary structure.
Without this fix, APB timer rating will be higher than LAPIC
timer such that it can not be released later to be used as the
broadcast timer.
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
LKML-Reference: <1298506046-439-1-git-send-email-jacob.jun.pan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In the dr_intercept function a new cpu-feature called
decode-assists is implemented and used when available. This
code-path does not advance the guest-rip causing the guest
to dead-loop over mov-dr instructions. This is fixed by this
patch.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
VersaLogic Menlow based boards hang on reboot unless reboot=bios
is used. Add quirk to reboot through the BIOS.
Tested on at least four boards.
Signed-off-by: Kushal Koolwal <kushalkoolwal@gmail.com>
LKML-Reference: <1298152563-21594-1-git-send-email-kushalkoolwal@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Just as we had to disable auto-demotion for NHM/WSM,
we need to do the same for Atom (Lincroft version).
In particular, auto-demotion will prevent Lincroft
from entering the S0i3 idle power saving state.
https://bugzilla.kernel.org/show_bug.cgi?id=25252
Signed-off-by: Len Brown <len.brown@intel.com>
Hardware C-state auto-demotion is a mechanism where the HW overrides
the OS C-state request, instead demoting to a shallower state,
which is less expensive, but saves less power.
Modern Linux should generally get exactly the states it requests.
In particular, when a CPU is taken off-line, it must not be demoted, else
it can prevent the entire package from reaching deep C-states.
https://bugzilla.kernel.org/show_bug.cgi?id=25252
Signed-off-by: Len Brown <len.brown@intel.com>
Several people have reported spurious unknown NMI
messages on some P4 CPUs.
This patch fixes it by checking for an overflow (negative
counter values) directly, instead of relying on the
P4_CCCR_OVF bit.
Reported-by: George Spelvin <linux@horizon.com>
Reported-by: Meelis Roos <mroos@linux.ee>
Reported-by: Don Zickus <dzickus@redhat.com>
Reported-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Lin Ming <ming.m.lin@intel.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <AANLkTinfuTfCck_FfaOHrDqQZZehtRzkBum4SpFoO=KJ@mail.gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: Fix text_poke_smp_batch() deadlock
perf tools: Fix thread_map event synthesizing in top and record
watchdog, nmi: Lower the severity of error messages
ARM: oprofile: Fix backtraces in timer mode
oprofile: Fix usage of CONFIG_HW_PERF_EVENTS for oprofile_perf_init and friends
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, dmi, debug: Log board name (when present) in dmesg/oops output
x86, ioapic: Don't warn about non-existing IOAPICs if we have none
x86: Fix mwait_usable section mismatch
x86: Readd missing irq_to_desc() in fixup_irq()
x86: Fix section mismatch in LAPIC initialization
The "Type 2" SMBIOS record that contains Board Name is not
strictly required and may be absent in the SMBIOS on some
platforms.
( Please note that Type 2 is not listed in Table 3 in Sec 6.2
("Required Structures and Data") of the SMBIOS v2.7
Specification. )
Use the Manufacturer Name (aka System Vendor) name.
Print Board Name only when it is present.
Before the fix:
(i) dmesg output: DMI: /ProLiant DL380 G6, BIOS P62 01/29/2011
(ii) oops output: Pid: 2170, comm: bash Not tainted 2.6.38-rc4+ #3 /ProLiant DL380 G6
After the fix:
(i) dmesg output: DMI: HP ProLiant DL380 G6, BIOS P62 01/29/2011
(ii) oops output: Pid: 2278, comm: bash Not tainted 2.6.38-rc4+ #4 HP ProLiant DL380 G6
Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Reviewed-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: <stable@kernel.org> # .3x - good for debugging, please apply as far back as it applies cleanly
LKML-Reference: <20110214224423.2182.13929.sendpatchset@nchumbalkar.americas.hpqcorp.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
mp_find_ioapic() prints errors like:
ERROR: Unable to locate IOAPIC for GSI 13
if it can't find the IOAPIC that manages that specific GSI. I
see errors like that at every boot of a laptop that apparently
doesn't have any IOAPICs.
But if there are no IOAPICs it doesn't seem to be an error that
none can be found. A solution that gets rid of this message is
to directly return if nr_ioapics (still) is zero. (But keep
returning -1 in that case, so nothing breaks from this change.)
The call chain that generates this error is:
pnpacpi_allocated_resource()
case ACPI_RESOURCE_TYPE_IRQ:
pnpacpi_parse_allocated_irqresource()
acpi_get_override_irq()
mp_find_ioapic()
Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
We use it in non __cpuinit code now too so drop marker.
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
LKML-Reference: <20110211171754.GA21047@aftab>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
commit a3c08e5d(x86: Convert irq_chip access to new functions)
accidentally zapped desc = irq_to_desc(irq); in the vector loop.
So we lock some random irq descriptor.
Add it back.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@kernel.org> # .37
Additionally doing things conditionally upon smp_processor_id()
being zero is generally a bad idea, as this means CPU 0 cannot
be offlined and brought back online later again.
While there may be other places where this is done, I think adding
more of those should be avoided so that some day SMP can really
become "symmetrical".
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
LKML-Reference: <4D525C7E0200007800030EE1@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The gs_index loading code uses the swapgs instruction to
switch to the user gs_base temporarily. This is unsave in an
lightweight exit-path in KVM on AMD because the
KERNEL_GS_BASE MSR is switches lazily. An NMI happening in
the critical path of load_gs_index may use the wrong GS_BASE
value then leading to unpredictable behavior, e.g. a
triple-fault.
This patch fixes the issue by making sure that load_gs_index
is called only with a valid KERNEL_GS_BASE value loaded in
KVM.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
We reserve lowmem for the things that need it, like the ACPI
wakeup code, way early to guarantee availability. This happens
before we set up the proper pagetables, so set_memory_x() has no
effect.
Until we have a better solution, use an initcall to mark the
wakeup code executable.
Originally-by: Matthieu Castet <castet.matthieu@free.fr>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Matthias Hopf <mhopf@suse.de>
Cc: rjw@sisk.pl
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <4D4F8019.2090104@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86-32: Make sure the stack is set up before we use it
x86, mtrr: Avoid MTRR reprogramming on BP during boot on UP platforms
x86, nx: Don't force pages RW when setting NX bits
Since checkin ebba638ae7 we call
verify_cpu even in 32-bit mode. Unfortunately, calling a function
means using the stack, and the stack pointer was not initialized in
the 32-bit setup code! This code initializes the stack pointer, and
simplifies the interface slightly since it is easier to rely on just a
pointer value rather than a descriptor; we need to have different
values for the segment register anyway.
This retains start_stack as a virtual address, even though a physical
address would be more convenient for 32 bits; the 64-bit code wants
the other way around...
Reported-by: Matthieu Castet <castet.matthieu@free.fr>
LKML-Reference: <4D41E86D.8060205@free.fr>
Tested-by: Kees Cook <kees.cook@canonical.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Clearing the cpu in prev's mm_cpumask early will avoid the flush tlb
IPI's while the cr3 is still pointing to the prev mm. And this window
can lead to the possibility of bogus TLB fills resulting in strange
failures. One such problematic scenario is mentioned below.
T1. CPU-1 is context switching from mm1 to mm2 context and got a NMI
etc between the point of clearing the cpu from the mm_cpumask(mm1)
and before reloading the cr3 with the new mm2.
T2. CPU-2 is tearing down a specific vma for mm1 and will proceed with
flushing the TLB for mm1. It doesn't send the flush TLB to CPU-1
as it doesn't see that cpu listed in the mm_cpumask(mm1).
T3. After the TLB flush is complete, CPU-2 goes ahead and frees the
page-table pages associated with the removed vma mapping.
T4. CPU-2 now allocates those freed page-table pages for something
else.
T5. As the CR3 and TLB caches for mm1 is still active on CPU-1, CPU-1
can potentially speculate and walk through the page-table caches
and can insert new TLB entries. As the page-table pages are
already freed and being used on CPU-2, this page walk can
potentially insert a bogus global TLB entry depending on the
(random) contents of the page that is being used on CPU-2.
T6. This bogus TLB entry being global will be active across future CR3
changes and can result in weird memory corruption etc.
To avoid this issue, for the prev mm that is handing over the cpu to
another mm, clear the cpu from the mm_cpumask(prev) after the cr3 is
changed.
Marking it for -stable, though we haven't seen any reported failure that
can be attributed to this.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: stable@kernel.org [v2.6.32+]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Markus Kohn ran into a hard hang regression on an acer aspire
1310, when acpi is enabled. git bisect showed the following
commit as the bad one that introduced the boot regression.
commit d0af9eed5a
Author: Suresh Siddha <suresh.b.siddha@intel.com>
Date: Wed Aug 19 18:05:36 2009 -0700
x86, pat/mtrr: Rendezvous all the cpus for MTRR/PAT init
Because of the UP configuration of that platform,
native_smp_prepare_cpus() bailed out (in smp_sanity_check())
before doing the set_mtrr_aps_delayed_init()
Further down the boot path, native_smp_cpus_done() will call the
delayed MTRR initialization for the AP's (mtrr_aps_init()) with
mtrr_aps_delayed_init not set. This resulted in the boot
processor reprogramming its MTRR's to the values seen during the
start of the OS boot. While this is not needed ideally, this
shouldn't have caused any side-effects. This is because the
reprogramming of MTRR's (set_mtrr_state() that gets called via
set_mtrr()) will check if the live register contents are
different from what is being asked to write and will do the actual
write only if they are different.
BP's mtrr state is read during the start of the OS boot and
typically nothing would have changed when we ask to reprogram it
on BP again because of the above scenario on an UP platform. So
on a normal UP platform no reprogramming of BP MTRR MSR's
happens and all is well.
However, on this platform, bios seems to be modifying the fixed
mtrr range registers between the start of OS boot and when we
double check the live registers for reprogramming BP MTRR
registers. And as the live registers are modified, we end up
reprogramming the MTRR's to the state seen during the start of
the OS boot.
During ACPI initialization, something in the bios (probably smi
handler?) don't like this fact and results in a hard lockup.
We didn't see this boot hang issue on this platform before the
commit d0af9eed5a, because only
the AP's (if any) will program its MTRR's to the value that BP
had at the start of the OS boot.
Fix this issue by checking mtrr_aps_delayed_init before
continuing further in the mtrr_aps_init(). Now, only AP's (if
any) will program its MTRR's to the BP values during boot.
Addresses https://bugzilla.novell.com/show_bug.cgi?id=623393
[ By the way, this behavior of the bios modifying MTRR's after the start
of the OS boot is not common and the kernel is not prepared to
handle this situation well. Irrespective of this issue, during
suspend/resume, linux kernel will try to reprogram the BP's MTRR values
to the values seen during the start of the OS boot. So suspend/resume might
be already broken on this platform for all linux kernel versions. ]
Reported-and-bisected-by: Markus Kohn <jabber@gmx.org>
Tested-by: Markus Kohn <jabber@gmx.org>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Thomas Renninger <trenn@novell.com>
Cc: Rafael Wysocki <rjw@novell.com>
Cc: Venkatesh Pallipadi <venki@google.com>
Cc: stable@kernel.org # [v2.6.32+]
LKML-Reference: <1296694975.4418.402.camel@sbsiddha-MOBL3.sc.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Xen want page table pages read only.
But the initial page table (from head_*.S) live in .data or .bss.
That was broken by 64edc8ed5f. There is
absolutely no reason to force these pages RW after they have already
been marked RO.
Signed-off-by: Matthieu CASTET <castet.matthieu@free.fr>
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* 'stable/bug-fixes-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
xen/setup: Route halt operations to safe_halt pvop.
xen/e820: Guard against E820_RAM not having page-aligned size or start.
xen/p2m: Mark INVALID_P2M_ENTRY the mfn_list past max_pfn.
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
percpu, x86: Fix percpu_xchg_op()
x86: Remove left over system_64.h
x86-64: Don't use pointer to out-of-scope variable in dump_trace()
This patch fixes some issues with raw event validation on
Pentium 4 (Netburst) based processors.
As I was testing libpfm4 Netburst support, I ran into two
problems in the p4_validate_raw_event() function:
- the shared field must be checked ONLY when HT is on
- the binding to ESCR register was missing
The second item was causing raw events to not be encoded
correctly compared to generic PMU events.
With this patch, I can now pass Netburst events to libpfm4
examples and get meaningful results:
$ task -e global_power_events🏃u noploop 1
noploop for 1 seconds
3,206,304,898 global_power_events:running
Signed-off-by: Stephane Eranian <eranian@google.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: peterz@infradead.org
Cc: paulus@samba.org
Cc: davem@davemloft.net
Cc: fweisbec@gmail.com
Cc: perfmon2-devel@lists.sf.net
Cc: eranian@gmail.com
Cc: robert.richter@amd.com
Cc: acme@redhat.com
Cc: gorcunov@gmail.com
Cc: ming.m.lin@intel.com
LKML-Reference: <4d3efb2f.1252d80a.1a80.ffffc83f@mx.google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
With this patch, the cpuidle driver does not load and
does not issue the mwait operations. Instead the hypervisor
is doing them (b/c we call the safe_halt pvops call).
This fixes quite a lot of bootup issues wherein the user had
to force interrupts for the continuation of the bootup.
Details are discussed in:
http://lists.xensource.com/archives/html/xen-devel/2011-01/msg00535.html
[v2: Wrote the commit description]
Reported-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Tested-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Under Dell Inspiron 1525, and Intel SandyBridge SDP's the
BIOS e820 RAM is not page-aligned:
[ 0.000000] Xen: 0000000000100000 - 00000000df66d800 (usable)
We were not handling that and ended up setting up a pagetable
that included up to df66e000 with the disastrous effect that when
memset(NODE_DATA(nodeid), 0, sizeof(pg_data_t));
tried to clear the page it would crash at the 2K mark.
Initially reported by Michael Young @
http://lists.xensource.com/archives/html/xen-devel/2011-01/msg00108.html
The fix is to page-align the size and also take into consideration
the start of the E820 (in case that is not page-aligned either). This
fixes the bootup failure on those affected machines.
This patch is a rework of the Micheal A Young initial patch and
considers the case if the start is not page-aligned.
Reported-by: Michael A Young <m.a.young@durham.ac.uk>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Michael A Young <m.a.young@durham.ac.uk>
In case the mfn_list does not have enough entries to fill
a p2m page we do not want the entries from max_pfn up to
the boundary to be filled with unknown values. Hence
set them to INVALID_P2M_ENTRY.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
These recent percpu commits:
2485b6464c: x86,percpu: Move out of place 64 bit ops into X86_64 section
8270137a0d: cpuops: Use cmpxchg for xchg to avoid lock semantics
Caused this 'perf top' crash:
Kernel panic - not syncing: Fatal exception in interrupt
Pid: 0, comm: swapper Tainted: G D
2.6.38-rc2-00181-gef71723 #413 Call Trace: <IRQ> [<ffffffff810465b5>]
? panic
? kmsg_dump
? kmsg_dump
? oops_end
? no_context
? __bad_area_nosemaphore
? perf_output_begin
? bad_area_nosemaphore
? do_page_fault
? __task_pid_nr_ns
? perf_event_tid
? __perf_event_header__init_id
? validate_chain
? perf_output_sample
? trace_hardirqs_off
? page_fault
? irq_work_run
? update_process_times
? tick_sched_timer
? tick_sched_timer
? __run_hrtimer
? hrtimer_interrupt
? account_system_vtime
? smp_apic_timer_interrupt
? apic_timer_interrupt
...
Looking at assembly code, I found:
list = this_cpu_xchg(irq_work_list, NULL);
gives this wrong code : (gcc-4.1.2 cross compiler)
ffffffff810bc45e:
mov %gs:0xead0,%rax
cmpxchg %rax,%gs:0xead0
jne ffffffff810bc45e <irq_work_run+0x3e>
test %rax,%rax
je ffffffff810bc4aa <irq_work_run+0x8a>
Tell gcc we dirty eax/rax register in percpu_xchg_op()
Compiler must use another register to store pxo_new__
We also dont need to reload percpu value after a jump,
since a 'failed' cmpxchg already updated eax/rax
Wrong generated code was :
xor %rax,%rax /* load 0 into %rax */
1: mov %gs:0xead0,%rax
cmpxchg %rax,%gs:0xead0
jne 1b
test %rax,%rax
After patch :
xor %rdx,%rdx /* load 0 into %rdx */
mov %gs:0xead0,%rax
1: cmpxchg %rdx,%gs:0xead0
jne 1b:
test %rax,%rax
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Tejun Heo <tj@kernel.org>
LKML-Reference: <1295973114.3588.312.camel@edumazet-laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Left-over from the x86 merge ...
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4D3E23D1.7010405@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This fixes TRANSPARENT_HUGEPAGE=y with PARAVIRT=y and HIGHMEM64=n.
The #ifdef that this patch removes was erratically introduced to fix a
build error for noPAE (where pmd.pmd doesn't exist). So then the kernel
built but it failed at runtime because set_pmd_at was a noop. This will
correct it by enabling set_pmd_at for noPAE mode too.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: werner <w.landgraf@ru.ru>
Reported-by: Minchan Kim <minchan.kim@gmail.com>
Tested-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In arch/x86/kernel/dumpstack_64.c::dump_trace() we have this code:
...
if (!stack) {
unsigned long dummy;
stack = &dummy;
if (task && task != current)
stack = (unsigned long *)task->thread.sp;
}
bp = stack_frame(task, regs);
/*
* Print function call entries in all stacks, starting at the
* current stack address. If the stacks consist of nested
* exceptions
*/
tinfo = task_thread_info(task);
for (;;) {
char *id;
unsigned long *estack_end;
estack_end = in_exception_stack(cpu, (unsigned long)stack,
&used, &id);
...
You'll notice that we assign to 'stack' the address of the variable
'dummy' which is only in-scope inside the 'if (!stack)'. So when we later
access stack (at the end of the above, and assuming we did not take the
'if (task && task != current)' branch) we'll be using the address of a
variable that is no longer in scope. I believe this patch is the proper
fix, but I freely admit that I'm not 100% certain.
Signed-off-by: Jesper Juhl <jj@chaosbits.net>
LKML-Reference: <alpine.LNX.2.00.1101242232590.10252@swampdragon.chaosbits.net>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
