Its broken, we really should get PERF_SAMPLE_REGS sorted.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There may exist constraints with a cmask set to zero. In this case
for_each_event_constraint() will not work properly. Now weight is used
instead of the cmask for loop exit detection. Weight is always a value
other than zero since the default contains the HWEIGHT from the
counter mask and in other cases a value of zero does not fit too.
This is in preparation of ibs event constraints that wont have a
cmask.
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1271190201-25705-7-git-send-email-robert.richter@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
To reuse this function for events with different enable bit masks,
this mask is part of the function's argument list now.
The function will be used later to control ibs events too.
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1271190201-25705-6-git-send-email-robert.richter@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The perfctr setup calls are in the corresponding .hw_config()
functions now. This makes it possible to introduce config functions
for other pmu events that are not perfctr specific.
Also, all of a sudden the code looks much nicer.
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1271190201-25705-4-git-send-email-robert.richter@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Move x86_setup_perfctr(), no other changes made.
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1271190201-25705-3-git-send-email-robert.richter@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Split __hw_perf_event_init() to configure pmu events other than
perfctrs. Perfctr code is moved to a separate function
x86_setup_perfctr(). This and the following patches refactor the code.
Split in multiple patches for better review.
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1271190201-25705-2-git-send-email-robert.richter@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
With F10, model 10, all valid frequencies are in the ACPI _PST table.
Cc: <stable@kernel.org> # 33.x 32.x
Signed-off-by: Mark Langsdorf <mark.langsdorf@amd.com>
LKML-Reference: <1270065406-1814-6-git-send-email-bp@amd64.org>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Reviewed-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The current policies of breakpoints in x86 and SH are the following:
- task bound breakpoints can only break on userspace addresses
- cpu wide breakpoints can only break on kernel addresses
The former rule prevents ptrace breakpoints to be set to trigger on
kernel addresses, which is good. But as a side effect, we can't
breakpoint on kernel addresses for task bound breakpoints.
The latter rule simply makes no sense, there is no reason why we
can't set breakpoints on userspace while performing cpu bound
profiles.
We want the following new policies:
- task bound breakpoint can set userspace address breakpoints, with
no particular privilege required.
- task bound breakpoints can set kernelspace address breakpoints but
must be privileged to do that.
- cpu bound breakpoints can do what they want as they are privileged
already.
To implement these new policies, this patch checks if we are dealing
with a kernel address breakpoint, if so and if the exclude_kernel
parameter is set, we tell the user that the breakpoint is invalid,
which makes a good generic ptrace protection.
If we don't have exclude_kernel, ensure the user has the right
privileges as kernel breakpoints are quite sensitive (risk of
trap recursion attacks and global performance impacts).
[ Paul Mundt: keep addr space check for sh signal delivery and fix
double function declaration]
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: K. Prasad <prasad@linux.vnet.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Tag ptrace breakpoints with the exclude_kernel attribute set. This
will make it easier to set generic policies on breakpoints, when it
comes to ensure nobody unpriviliged try to breakpoint on the kernel.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: K. Prasad <prasad@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Upstream PV guests fail to boot because of a NULL pointer in
irq_force_complete_move(). It is possible that xen guests have
irq_desc->chip_data = NULL.
Test for NULL chip_data pointer before attempting to complete an irq move.
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
LKML-Reference: <20100427152434.16193.49104.sendpatchset@prarit.bos.redhat.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: <stable@kernel.org> [2.6.33]
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-tip:
x86: Disable large pages on CPUs with Atom erratum AAE44
x86-64: Clear a 64-bit FS/GS base on fork if selector is nonzero
x86, mrst: Conditionally register cpu hotplug notifier for apbt
This is a standalone version of VMware Balloon driver. Ballooning is a
technique that allows hypervisor dynamically limit the amount of memory
available to the guest (with guest cooperation). In the overcommit
scenario, when hypervisor set detects that it needs to shuffle some
memory, it instructs the driver to allocate certain number of pages, and
the underlying memory gets returned to the hypervisor. Later hypervisor
may return memory to the guest by reattaching memory to the pageframes and
instructing the driver to "deflate" balloon.
We are submitting a standalone driver because KVM maintainer (Avi Kivity)
expressed opinion (rightly) that our transport does not fit well into
virtqueue paradigm and thus it does not make much sense to integrate with
virtio.
There were also some concerns whether current ballooning technique is the
right thing. If there appears a better framework to achieve this we are
prepared to evaluate and switch to using it, but in the meantime we'd like
to get this driver upstream.
We want to get the driver accepted in distributions so that users do not
have to deal with an out-of-tree module and many distributions have
"upstream first" requirement.
The driver has been shipping for a number of years and users running on
VMware platform will have it installed as part of VMware Tools even if it
will not come from a distribution, thus there should not be additional
risk in pulling the driver into mainline. The driver will only activate
if host is VMware so everyone else should not be affected at all.
Signed-off-by: Dmitry Torokhov <dtor@vmware.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Atom erratum AAE44/AAF40/AAG38/AAH41:
"If software clears the PS (page size) bit in a present PDE (page
directory entry), that will cause linear addresses mapped through this
PDE to use 4-KByte pages instead of using a large page after old TLB
entries are invalidated. Due to this erratum, if a code fetch uses
this PDE before the TLB entry for the large page is invalidated then
it may fetch from a different physical address than specified by
either the old large page translation or the new 4-KByte page
translation. This erratum may also cause speculative code fetches from
incorrect addresses."
[http://download.intel.com/design/processor/specupdt/319536.pdf]
Where as commit 211b3d03c7 seems to
workaround errata AAH41 (mixed 4K TLBs) it reduces the window of
opportunity for the bug to occur and does not totally remove it. This
patch disables mixed 4K/4MB page tables totally avoiding the page
splitting and not tripping this processor issue.
This is based on an original patch by Colin King.
Originally-by: Colin Ian King <colin.king@canonical.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
LKML-Reference: <1269271251-19775-1-git-send-email-colin.king@canonical.com>
Cc: <stable@kernel.org>
When we do a thread switch, we clear the outgoing FS/GS base if the
corresponding selector is nonzero. This is taken by __switch_to() as
an entry invariant; it does not verify that it is true on entry.
However, copy_thread() doesn't enforce this constraint, which can
result in inconsistent results after fork().
Make copy_thread() match the behavior of __switch_to().
Reported-and-tested-by: Samuel Thibault <samuel.thibault@inria.fr>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
LKML-Reference: <4BD1E061.8030605@zytor.com>
Cc: <stable@kernel.org>
APB timer is used on Moorestown platforms but not on a standard PC.
If APB timer code is compiled in but not initialized at run-time due
to lack of FW reported SFI table, kernel would panic when the non-boot
CPUs are offlined and notifier is called.
https://bugzilla.kernel.org/show_bug.cgi?id=15786
This patch ensures CPU hotplug notifier for APB timer is only registered
when the APBT timer block is initialized.
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
LKML-Reference: <1271701423-1162-1-git-send-email-jacob.jun.pan@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Below patch introduces perf_guest_info_callbacks and related
register/unregister functions. Add more PERF_RECORD_MISC_XXX bits
meaning guest kernel and guest user space.
Signed-off-by: Zhang Yanmin <yanmin_zhang@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
When we fetch the hot regs and rewind to the nth caller, it
might happen that we dereference a frame pointer outside the
kernel stack boundaries, like in this example:
perf_trace_sched_switch+0xd5/0x120
schedule+0x6b5/0x860
retint_careful+0xd/0x21
Since we directly dereference a userspace frame pointer here while
rewinding behind retint_careful, this may end up in a crash.
Fix this by simply using probe_kernel_address() when we rewind the
frame pointer.
This issue will have a much more proper fix in the next version of the
perf_arch_fetch_caller_regs() API that will only need to rewind to the
first caller.
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Tested-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: David Miller <davem@davemloft.net>
Cc: Archs <linux-arch@vger.kernel.org>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-tip:
x86: Fix double enable_IR_x2apic() call on SMP kernel on !SMP boards
x86: Increase CONFIG_NODES_SHIFT max to 10
ibft, x86: Change reserve_ibft_region() to find_ibft_region()
x86, hpet: Fix bug in RTC emulation
x86, hpet: Erratum workaround for read after write of HPET comparator
bootmem, x86: Fix 32bit numa system without RAM on node 0
nobootmem, x86: Fix 32bit numa system without RAM on node 0
x86: Handle overlapping mptables
x86: Make e820_remove_range to handle all covered case
x86-32, resume: do a global tlb flush in S4 resume
If we boot into a crash-kernel the gart might still be
enabled and its caches might be dirty. This can result in
undefined behavior later. Fix it by explicitly disabling the
gart hardware before initialization and flushing the caches
after enablement.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
This effectively reverts commit 61d047be99.
Disabling the IOMMU can potetially allow DMA transactions to
complete without being translated. Leave it enabled, and allow
crash kernel to do the IOMMU reinitialization properly.
Cc: stable@kernel.org
Cc: Joerg Roedel <joerg.roedel@amd.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
To catch future potential issues we can add a warning whenever we issue
a command before the command buffer is fully initialized.
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Hit another kdump problem as reported by Neil Horman. When initializaing
the IOMMU, we attach devices to their domains before the IOMMU is
fully (re)initialized. Attaching a device will issue some important
invalidations. In the context of the newly kexec'd kdump kernel, the
IOMMU may have stale cached data from the original kernel. Because we
do the attach too early, the invalidation commands are placed in the new
command buffer before the IOMMU is updated w/ that buffer. This leaves
the stale entries in the kdump context and can renders device unusable.
Simply enable the IOMMU before we do the attach.
Cc: stable@kernel.org
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
According to Intel Software Devel Manual Volume 3B, the
Nehalem-EX PMU is just like regular Nehalem (except for the
uncore support, which is completely different).
Signed-off-by: Vince Weaver <vweaver1@eecs.utk.edu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Lin Ming <ming.m.lin@intel.com>
LKML-Reference: <alpine.DEB.2.00.1004060956580.1417@cl320.eecs.utk.edu>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
It is useless now that we have a pure stack frame
walker, as given addr are always reliable.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Jan Grossmann reported kernel boot panic while booting SMP
kernel on his system with a single core cpu. SMP kernels call
enable_IR_x2apic() from native_smp_prepare_cpus() and on
platforms where the kernel doesn't find SMP configuration we
ended up again calling enable_IR_x2apic() from the
APIC_init_uniprocessor() call in the smp_sanity_check(). Thus
leading to kernel panic.
Don't call enable_IR_x2apic() and default_setup_apic_routing()
from APIC_init_uniprocessor() in CONFIG_SMP case.
NOTE: this kind of non-idempotent and assymetric initialization
sequence is rather fragile and unclean, we'll clean that up
in v2.6.35. This is the minimal fix for v2.6.34.
Reported-by: Jan.Grossmann@kielnet.net
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: <jbarnes@virtuousgeek.org>
Cc: <david.woodhouse@intel.com>
Cc: <weidong.han@intel.com>
Cc: <youquan.song@intel.com>
Cc: <Jan.Grossmann@kielnet.net>
Cc: <stable@kernel.org> # [v2.6.32.x, v2.6.33.x]
LKML-Reference: <1270083887.7835.78.camel@sbs-t61.sc.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
According to the Xeon-5600 errata the Westmere suffers the same PMU
programming bug as the original Nehalem did.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
All variables that have __initconst should also be const.
Suggested-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Stephane noticed that the ANY flag was in generic arch code, and Cyrill
reported that it broke the P4 code.
Solve this by merging x86_pmu::raw_event into x86_pmu::hw_config and
provide intel_pmu and amd_pmu specific versions of this callback.
The intel_pmu one deals with the ANY flag, the amd_pmu adds the few extra
event bits AMD64 has.
Reported-by: Stephane Eranian <eranian@google.com>
Reported-by: Cyrill Gorcunov <gorcunov@gmail.com>
Acked-by: Robert Richter <robert.richter@amd.com>
Acked-by: Cyrill Gorcunov <gorcunov@gmail.com>
Acked-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1269968113.5258.442.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
ARCH_PERFMON_EVENTSEL bit masks are often used in the kernel. This
patch adds macros for the bit masks and removes local defines. The
function intel_pmu_raw_event() becomes x86_pmu_raw_event() which is
generic for x86 models and same also for p6. Duplicate code is
removed.
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100330092821.GH11907@erda.amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The big rename:
cdd6c48 perf: Do the big rename: Performance Counters -> Performance Events
accidentally renamed some members of stucts that were named after
registers in the spec. To avoid confusion this patch reverts some
changes. The related specs are MSR descriptions in AMD's BKDGs and the
ARCHITECTURAL PERFORMANCE MONITORING section in the Intel 64 and IA-32
Architectures Software Developer's Manuals.
This patch does:
$ sed -i -e 's:num_events:num_counters:g' \
arch/x86/include/asm/perf_event.h \
arch/x86/kernel/cpu/perf_event_amd.c \
arch/x86/kernel/cpu/perf_event.c \
arch/x86/kernel/cpu/perf_event_intel.c \
arch/x86/kernel/cpu/perf_event_p6.c \
arch/x86/kernel/cpu/perf_event_p4.c \
arch/x86/oprofile/op_model_ppro.c
$ sed -i -e 's:event_bits:cntval_bits:g' -e 's:event_mask:cntval_mask:g' \
arch/x86/kernel/cpu/perf_event_amd.c \
arch/x86/kernel/cpu/perf_event.c \
arch/x86/kernel/cpu/perf_event_intel.c \
arch/x86/kernel/cpu/perf_event_p6.c \
arch/x86/kernel/cpu/perf_event_p4.c
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1269880612-25800-2-git-send-email-robert.richter@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When profiling a 32-bit process on a 64-bit kernel, callgraph tracing
stopped after the first function, because it has seen a garbage memory
address (tried to interpret the frame pointer, and return address as a
64-bit pointer).
Fix this by using a struct stack_frame with 32-bit pointers when the
TIF_IA32 flag is set.
Note that TIF_IA32 flag must be used, and not is_compat_task(), because
the latter is only set when the 32-bit process is executing a syscall,
which may not always be the case (when tracing page fault events for
example).
Signed-off-by: Török Edwin <edwintorok@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
LKML-Reference: <1268820436-13145-1-git-send-email-edwintorok@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Commit 3f6da39 ("perf: Rework and fix the arch CPU-hotplug hooks") moved
the amd northbridge allocation from CPUS_ONLINE to CPUS_PREPARE_UP
however amd_nb_id() doesn't work yet on prepare so it would simply bail
basically reverting to a state where we do not properly track node wide
constraints - causing weird perf results.
Fix up the AMD NorthBridge initialization code by allocating from
CPU_UP_PREPARE and installing it from CPU_STARTING once we have the
proper nb_id. It also properly deals with the allocation failing.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
[ robustify using amd_has_nb() ]
Signed-off-by: Stephane Eranian <eranian@google.com>
LKML-Reference: <1269353485.5109.48.camel@twins>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Because we need to have cpu identification things done by the time we run
CPU_STARTING notifiers.
( This init ordering will be relied on by the next fix. )
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1269353485.5109.48.camel@twins>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This allows arch code could decide the way to reserve the ibft.
And we should reserve ibft as early as possible, instead of BOOTMEM
stage, in case the table is in RAM range and is not reserved by BIOS
(this will often be the case.)
Move to just after find_smp_config().
Also when CONFIG_NO_BOOTMEM=y, We will not have reserve_bootmem() anymore.
-v2: fix typo about ibft pointed by Konrad Rzeszutek Wilk <konrad@darnok.org>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4BB510FB.80601@kernel.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Peter Jones <pjones@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad@kernel.org>
CC: Jan Beulich <jbeulich@novell.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
We think there exists a bug in the HPET code that emulates the RTC.
In the normal case, when the RTC frequency is set, the rtc driver tells
the hpet code about it here:
int hpet_set_periodic_freq(unsigned long freq)
{
uint64_t clc;
if (!is_hpet_enabled())
return 0;
if (freq <= DEFAULT_RTC_INT_FREQ)
hpet_pie_limit = DEFAULT_RTC_INT_FREQ / freq;
else {
clc = (uint64_t) hpet_clockevent.mult * NSEC_PER_SEC;
do_div(clc, freq);
clc >>= hpet_clockevent.shift;
hpet_pie_delta = (unsigned long) clc;
}
return 1;
}
If freq is set to 64Hz (DEFAULT_RTC_INT_FREQ) or lower, then
hpet_pie_limit (a static) is set to non-zero. Then, on every one-shot
HPET interrupt, hpet_rtc_timer_reinit is called to compute the next
timeout. Well, that function has this logic:
if (!(hpet_rtc_flags & RTC_PIE) || hpet_pie_limit)
delta = hpet_default_delta;
else
delta = hpet_pie_delta;
Since hpet_pie_limit is not 0, hpet_default_delta is used. That
corresponds to 64Hz.
Now, if you set a different rtc frequency, you'll take the else path
through hpet_set_periodic_freq, but unfortunately no one resets
hpet_pie_limit back to 0.
Boom....now you are stuck with 64Hz RTC interrupts forever.
The patch below just resets the hpet_pie_limit value when requested freq
is greater than DEFAULT_RTC_INT_FREQ, which we think fixes this problem.
Signed-off-by: Alok N Kataria <akataria@vmware.com>
LKML-Reference: <201003112200.o2BM0Hre012875@imap1.linux-foundation.org>
Signed-off-by: Daniel Hecht <dhecht@vmware.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
On Wed, Feb 24, 2010 at 03:37:04PM -0800, Justin Piszcz wrote:
> Hello,
>
> Again, on the Intel DP55KG board:
>
> # uname -a
> Linux host 2.6.33 #1 SMP Wed Feb 24 18:31:00 EST 2010 x86_64 GNU/Linux
>
> [ 1.237600] ------------[ cut here ]------------
> [ 1.237890] WARNING: at arch/x86/kernel/hpet.c:404 hpet_next_event+0x70/0x80()
> [ 1.238221] Hardware name:
> [ 1.238504] hpet: compare register read back failed.
> [ 1.238793] Modules linked in:
> [ 1.239315] Pid: 0, comm: swapper Not tainted 2.6.33 #1
> [ 1.239605] Call Trace:
> [ 1.239886] <IRQ> [<ffffffff81056c13>] ? warn_slowpath_common+0x73/0xb0
> [ 1.240409] [<ffffffff81079608>] ? tick_dev_program_event+0x38/0xc0
> [ 1.240699] [<ffffffff81056cb0>] ? warn_slowpath_fmt+0x40/0x50
> [ 1.240992] [<ffffffff81079608>] ? tick_dev_program_event+0x38/0xc0
> [ 1.241281] [<ffffffff81041ad0>] ? hpet_next_event+0x70/0x80
> [ 1.241573] [<ffffffff81079608>] ? tick_dev_program_event+0x38/0xc0
> [ 1.241859] [<ffffffff81078e32>] ? tick_handle_oneshot_broadcast+0xe2/0x100
> [ 1.246533] [<ffffffff8102a67a>] ? timer_interrupt+0x1a/0x30
> [ 1.246826] [<ffffffff81085499>] ? handle_IRQ_event+0x39/0xd0
> [ 1.247118] [<ffffffff81087368>] ? handle_edge_irq+0xb8/0x160
> [ 1.247407] [<ffffffff81029f55>] ? handle_irq+0x15/0x20
> [ 1.247689] [<ffffffff810294a2>] ? do_IRQ+0x62/0xe0
> [ 1.247976] [<ffffffff8146be53>] ? ret_from_intr+0x0/0xa
> [ 1.248262] <EOI> [<ffffffff8102f277>] ? mwait_idle+0x57/0x80
> [ 1.248796] [<ffffffff8102645c>] ? cpu_idle+0x5c/0xb0
> [ 1.249080] ---[ end trace db7f668fb6fef4e1 ]---
>
> Is this something Intel has to fix or is it a bug in the kernel?
This is a chipset erratum.
Thomas: You mentioned we can retain this check only for known-buggy and
hpet debug kind of options. But here is the simple workaround patch for
this particular erratum.
Some chipsets have a erratum due to which read immediately following a
write of HPET comparator returns old comparator value instead of most
recently written value.
Erratum 15 in
"Intel I/O Controller Hub 9 (ICH9) Family Specification Update"
(http://www.intel.com/assets/pdf/specupdate/316973.pdf)
Workaround for the errata is to read the comparator twice if the first
one fails.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
LKML-Reference: <20100225185348.GA9674@linux-os.sc.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@gmail.com>
Cc: <stable@kernel.org>
We found a system where the MP table MPC and MPF structures overlap.
That doesn't really matter because the mptable is not used anyways with ACPI,
but it leads to a panic in the early allocator due to the overlapping
reservations in 2.6.33.
Earlier kernels handled this without problems.
Simply change these reservations to reserve_early_overlap_ok to avoid
the panic.
Reported-by: Thomas Renninger <trenn@suse.de>
Tested-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
LKML-Reference: <20100329074111.GA22821@basil.fritz.box>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: <stable@kernel.org>
