PER_CPU_VAR(kernel_stack) was set up in a way where it points
five stack slots below the top of stack.
Presumably, it was done to avoid one "sub $5*8,%rsp"
in syscall/sysenter code paths, where iret frame needs to be
created by hand.
Ironically, none of them benefits from this optimization,
since all of them need to allocate additional data on stack
(struct pt_regs), so they still have to perform subtraction.
This patch eliminates KERNEL_STACK_OFFSET.
PER_CPU_VAR(kernel_stack) now points directly to top of stack.
pt_regs allocations are adjusted to allocate iret frame as well.
Hopefully we can merge it later with 32-bit specific
PER_CPU_VAR(cpu_current_top_of_stack) variable...
Net result in generated code is that constants in several insns
are changed.
This change is necessary for changing struct pt_regs creation
in SYSCALL64 code path from MOV to PUSH instructions.
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Acked-by: Borislav Petkov <bp@suse.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1426785469-15125-2-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add a severities function that caters to AMD processors. This allows us
to do some vendor-specific work within the function if necessary.
Also, introduce a vendor flag bitfield for vendor-specific settings. The
severities code uses this to define error scope based on the prescence
of the flags field.
This is based off of work by Boris Petkov.
Testing details:
Fam10h, Model 9h (Greyhound)
Fam15h: Models 0h-0fh (Orochi), 30h-3fh (Kaveri) and 60h-6fh (Carrizo),
Fam16h Model 00h-0fh (Kabini)
Boris:
Intel SNB
AMD K8 (JH-E0)
Signed-off-by: Aravind Gopalakrishnan <aravind.gopalakrishnan@amd.com>
Acked-by: Tony Luck <tony.luck@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Chen Yucong <slaoub@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: linux-edac@vger.kernel.org
Link: http://lkml.kernel.org/r/1427125373-2918-2-git-send-email-Aravind.Gopalakrishnan@amd.com
[ Fixup build, clean up comments. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Having syscall32/sysenter32 initialization in a separate tiny
function, called from within a function that is already syscall
init specific, serves no real purpose.
Its existense also caused an unintended effect of having
wrmsrl(MSR_CSTAR) performed twice: once we set it to a dummy
function returning -ENOSYS, and immediately after
(if CONFIG_IA32_EMULATION), we set it to point to the proper
syscall32 entry point, ia32_cstar_target.
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Acked-by: Andy Lutomirski <luto@amacapital.net>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The private pointer provided by the cacheinfo code is used to implement
the AMD L3 cache-specific attributes using a pointer to the northbridge
descriptor. It is needed for performing L3-specific operations and for
that we need a couple of PCI devices and other service information, all
contained in the northbridge descriptor.
This results in failure of cacheinfo setup as shown below as
cache_get_priv_group() returns the uninitialised private attributes which
are not valid for Intel processors.
------------[ cut here ]------------
WARNING: CPU: 3 PID: 1 at fs/sysfs/group.c:102
internal_create_group+0x151/0x280()
sysfs: (bin_)attrs not set by subsystem for group: index3/
Modules linked in:
CPU: 3 PID: 1 Comm: swapper/0 Not tainted 4.0.0-rc3+ #1
Hardware name: Dell Inc. Precision T3600/0PTTT9, BIOS A13 05/11/2014
...
Call Trace:
dump_stack
warn_slowpath_common
warn_slowpath_fmt
internal_create_group
sysfs_create_groups
device_add
cpu_device_create
? __kmalloc
cache_add_dev
cacheinfo_sysfs_init
? container_dev_init
do_one_initcall
kernel_init_freeable
? rest_init
kernel_init
ret_from_fork
? rest_init
This patch fixes the issue by checking if the L3 cache indices are
populated correctly (AMD-specific) before initializing the private
attributes.
Reported-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Before the patch, the 'tss_struct::stack' field was not referenced anywhere.
It was used only to set SYSENTER's stack to point after the last byte
of tss_struct, thus the trailing field, stack[64], was used.
But grep would not know it. You can comment it out, compile,
and kernel will even run until an unlucky NMI corrupts
io_bitmap[] (which is also not easily detectable).
This patch changes code so that the purpose and usage of this
field is not mysterious anymore, and can be easily grepped for.
This does change generated code, for a subtle reason:
since tss_struct is ____cacheline_aligned, there happens to be
5 longs of padding at the end. Old code was using the padding
too; new code will strictly use it only for SYSENTER_stack[].
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1425912738-559-2-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch removes the redundant sysfs cacheinfo code by reusing
the newly introduced generic cacheinfo infrastructure through the
commit
246246cbde ("drivers: base: support cpu cache information
interface to userspace via sysfs")
The private pointer provided by the cacheinfo is used to implement
the AMD L3 cache-specific attributes.
Note that with v4.0-rc1, commit
513e3d2d11 ("cpumask: always use nr_cpu_ids in formatting and parsing
functions")
in particular changes from long format to shorter one for all cpumasks
sysfs entries. As the consequence of the same, even the shared_cpu_map
in the cacheinfo sysfs was also changed.
This patch neither alters any existing sysfs entries nor their
formating, however since the generic cacheinfo has switched to use the
device attributes instead of the traditional raw kobjects, a directory
named "power" along with its standard attributes are added similar to
any other device.
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andre Przywara <andre.przywara@arm.com>
Link: http://lkml.kernel.org/r/1425470416-20691-1-git-send-email-sudeep.holla@arm.com
[ Add a check for uninitialized this_cpu_ci for the cpu_has_topoext case too
in __cache_amd_cpumap_setup() ]
Signed-off-by: Borislav Petkov <bp@suse.de>
I broke 32-bit kernels. The implementation of sp0 was correct
as far as I can tell, but sp0 was much weirder on x86_32 than I
realized. It has the following issues:
- Init's sp0 is inconsistent with everything else's: non-init tasks
are offset by 8 bytes. (I have no idea why, and the comment is unhelpful.)
- vm86 does crazy things to sp0.
Fix it up by replacing this_cpu_sp0() with
current_top_of_stack() and using a new percpu variable to track
the top of the stack on x86_32.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 75182b1632 ("x86/asm/entry: Switch all C consumers of kernel_stack to this_cpu_sp0()")
Link: http://lkml.kernel.org/r/d09dbe270883433776e0cbee3c7079433349e96d.1425692936.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull alternative instructions framework improvements from Borislav Petkov:
"A more involved rework of the alternatives framework to be able to
pad instructions and thus make using the alternatives macros more
straightforward and without having to figure out old and new instruction
sizes but have the toolchain figure that out for us.
Furthermore, it optimizes JMPs used so that fetch and decode can be
relieved with smaller versions of the JMPs, where possible.
Some stats:
x86_64 defconfig:
Alternatives sites total: 2478
Total padding added (in Bytes): 6051
The padding is currently done for:
X86_FEATURE_ALWAYS
X86_FEATURE_ERMS
X86_FEATURE_LFENCE_RDTSC
X86_FEATURE_MFENCE_RDTSC
X86_FEATURE_SMAP
This is with the latest version of the patchset. Of course, on each
machine the alternatives sites actually being patched are a proper
subset of the total number."
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x86 microcode loader code cleanups from Borislav Petkov:
"The first part of the scrubbing of the intel early microcode loader.
There's more work to come but let's unload this pile first."
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When doing
echo 1 > /sys/devices/system/cpu/microcode/reload
in order to reload microcode, I get:
microcode: Total microcode saved: 1
BUG: using smp_processor_id() in preemptible [00000000] code: bash/2606
caller is debug_smp_processor_id+0x17/0x20
CPU: 1 PID: 2606 Comm: bash Not tainted 3.19.0-rc7+ #9
Hardware name: LENOVO 2320CTO/2320CTO, BIOS G2ET86WW (2.06 ) 11/13/2012
ffffffff81a4266d ffff8802131db808 ffffffff81666588 0000000000000007
0000000000000001 ffff8802131db838 ffffffff812e6eef ffff8802131db868
00000000000306a9 0000000000000010 0000000000000015 ffff8802131db848
Call Trace:
dump_stack
check_preemption_disabled
debug_smp_processor_id
show_saved_mc
? save_microcode.constprop.8
save_mc_for_early
? print_context_stack
? dump_trace
? __bfs
? mark_held_locks
? get_page_from_freelist
? trace_hardirqs_on_caller
? trace_hardirqs_on
? __alloc_pages_nodemask
? __get_vm_area_node
? map_vm_area
? __vmalloc_node_range
? generic_load_microcode
generic_load_microcode
? microcode_fini_cpu
request_microcode_fw
reload_store
dev_attr_store
sysfs_kf_write
kernfs_fop_write
vfs_write
? sysret_check
SyS_write
system_call_fastpath
microcode: CPU1: sig=0x306a9, pf=0x10, rev=0x15
microcode: mc_saved[0]: sig=0x306a9, pf=0x12, rev=0x1b, toal size=0x3000, date = 2014-05-29
because we're using smp_processor_id() in preemtible context. And we
don't really need to use it there because the microcode container we're
dumping is global and CPU-specific info is irrelevant.
While at it, make pr_* stuff use "microcode: " prefix for easier
grepping and document how to enable the DEBUG build.
Signed-off-by: Borislav Petkov <bp@suse.de>
... arguments list so that it comes more natural for those functions to
have the signature, processor flags and revision together, before the
rest of the args.
No functionality change.
Signed-off-by: Borislav Petkov <bp@suse.de>
* remove state variable and out label
* get rid of completely unused mc_size
* shorten variable names
* get rid of local variables
* don't do assignments in local var declarations for less cluttered code
* finally rename it to the shorter and perfectly fine load_microcode_early()
No functionality change.
Signed-off-by: Borislav Petkov <bp@suse.de>
... to the header. Split the family acquiring function into a
main one, doing CPUID and a helper which computes the extended
family and is used in multiple places. Get rid of the locally-grown
get_x86_{family,model}().
While at it, rename local variables to something more descriptive and
vertically align assignments for better readability.
There should be no functionality change resulting from this patch.
Signed-off-by: Borislav Petkov <bp@suse.de>
Shorten local variable names for better readability and flatten loop
indentation levels.
No functionality change.
Signed-off-by: Borislav Petkov <bp@suse.de>
... of microcode patches instead of handing in a pointer which is used
for I/O in an otherwise void function.
Signed-off-by: Borislav Petkov <bp@suse.de>
Don't compute start and end from start and size in order to compute size
again down the path in scan_microcode(). So pass size directly instead
and simplify a bunch. Shorten variable names and remove useless ones.
Signed-off-by: Borislav Petkov <bp@suse.de>
... and only then deref it. Also, shorten some variable names and rename
others so as to diminish the ubiquitous presence of the "mc_" prefix
everywhere and make it a bit more readable.
Use kcalloc so that we don't kfree() uninitialized memory on the unwind
path, as suggested by Quentin.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
We should check the return value of the routines fishing out the proper
microcode and not try to apply if we haven't found a suitable blob.
Signed-off-by: Borislav Petkov <bp@suse.de>
We can leverage the workqueue that we use for RMID rotation to support
scheduling of conflicting monitoring events. Allowing events that
monitor conflicting things is done at various other places in the perf
subsystem, so there's precedent there.
An example of two conflicting events would be monitoring a cgroup and
simultaneously monitoring a task within that cgroup.
This uses the cache_groups list as a queuing mechanism, where every
event that reaches the front of the list gets the chance to be scheduled
in, possibly descheduling any conflicting events that are running.
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kanaka Juvva <kanaka.d.juvva@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Link: http://lkml.kernel.org/r/1422038748-21397-10-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There are many use cases where people will want to monitor more tasks
than there exist RMIDs in the hardware, meaning that we have to perform
some kind of multiplexing.
We do this by "rotating" the RMIDs in a workqueue, and assigning an RMID
to a waiting event when the RMID becomes unused.
This scheme reserves one RMID at all times for rotation. When we need to
schedule a new event we give it the reserved RMID, pick a victim event
from the front of the global CQM list and wait for the victim's RMID to
drop to zero occupancy, before it becomes the new reserved RMID.
We put the victim's RMID onto the limbo list, where it resides for a
"minimum queue time", which is intended to save ourselves an expensive
smp IPI when the RMID is unlikely to have a occupancy value below
__intel_cqm_threshold.
If we fail to recycle an RMID, even after waiting the minimum queue time
then we need to increment __intel_cqm_threshold. There is an upper bound
on this threshold, __intel_cqm_max_threshold, which is programmable from
userland as /sys/devices/intel_cqm/max_recycling_threshold.
The comments above __intel_cqm_rmid_rotate() have more details.
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kanaka Juvva <kanaka.d.juvva@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Link: http://lkml.kernel.org/r/1422038748-21397-9-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add support for task events as well as system-wide events. This change
has a big impact on the way that we gather LLC occupancy values in
intel_cqm_event_read().
Currently, for system-wide (per-cpu) events we defer processing to
userspace which knows how to discard all but one cpu result per package.
Things aren't so simple for task events because we need to do the value
aggregation ourselves. To do this, we defer updating the LLC occupancy
value in event->count from intel_cqm_event_read() and do an SMP
cross-call to read values for all packages in intel_cqm_event_count().
We need to ensure that we only do this for one task event per cache
group, otherwise we'll report duplicate values.
If we're a system-wide event we want to fallback to the default
perf_event_count() implementation. Refactor this into a common function
so that we don't duplicate the code.
Also, introduce PERF_TYPE_INTEL_CQM, since we need a way to track an
event's task (if the event isn't per-cpu) inside of the Intel CQM PMU
driver. This task information is only availble in the upper layers of
the perf infrastructure.
Other perf backends stash the target task in event->hw.*target so we
need to do something similar. The task is used to determine whether
events should share a cache group and an RMID.
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kanaka Juvva <kanaka.d.juvva@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Cc: linux-api@vger.kernel.org
Link: http://lkml.kernel.org/r/1422038748-21397-8-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This is based on a patch originally by hpa.
With the current improvements to the alternatives, we can simply use %P1
as a mem8 operand constraint and rely on the toolchain to generate the
proper instruction sizes. For example, on 32-bit, where we use an empty
old instruction we get:
apply_alternatives: feat: 6*32+8, old: (c104648b, len: 4), repl: (c195566c, len: 4)
c104648b: alt_insn: 90 90 90 90
c195566c: rpl_insn: 0f 0d 4b 5c
...
apply_alternatives: feat: 6*32+8, old: (c18e09b4, len: 3), repl: (c1955948, len: 3)
c18e09b4: alt_insn: 90 90 90
c1955948: rpl_insn: 0f 0d 08
...
apply_alternatives: feat: 6*32+8, old: (c1190cf9, len: 7), repl: (c1955a79, len: 7)
c1190cf9: alt_insn: 90 90 90 90 90 90 90
c1955a79: rpl_insn: 0f 0d 0d a0 d4 85 c1
all with the proper padding done depending on the size of the
replacement instruction the compiler generates.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Pull misc x86 fixes from Ingo Molnar:
"This contains:
- EFI fixes
- a boot printout fix
- ASLR/kASLR fixes
- intel microcode driver fixes
- other misc fixes
Most of the linecount comes from an EFI revert"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm/ASLR: Avoid PAGE_SIZE redefinition for UML subarch
x86/microcode/intel: Handle truncated microcode images more robustly
x86/microcode/intel: Guard against stack overflow in the loader
x86, mm/ASLR: Fix stack randomization on 64-bit systems
x86/mm/init: Fix incorrect page size in init_memory_mapping() printks
x86/mm/ASLR: Propagate base load address calculation
Documentation/x86: Fix path in zero-page.txt
x86/apic: Fix the devicetree build in certain configs
Revert "efi/libstub: Call get_memory_map() to obtain map and desc sizes"
x86/efi: Avoid triple faults during EFI mixed mode calls
Pull microcode fixes from Borislav Petkov:
- Two fixes hardening microcode data handling. (Quentin Casasnovas)
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull RAS updates from Borislav Petkov:
"- Enable AMD thresholding IRQ by default if supported. (Aravind Gopalakrishnan)
- Unify mce_panic() message pattern. (Derek Che)
- A bit more involved simplification of the CMCI logic after yet another
report about race condition with the adaptive logic. (Borislav Petkov)
- ACPI APEI EINJ fleshing out of the user documentation. (Borislav Petkov)
- Minor cleanup. (Jan Beulich.)"
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We setup APIC vectors for threshold errors if interrupt_capable.
However, we don't set interrupt_enable by default. Rework
threshold_restart_bank() so that when we set up lvt_offset, we also set
IntType to APIC and also enable thresholding interrupts for banks which
support it by default.
User is still allowed to disable interrupts through sysfs.
While at it, check if status is valid before we proceed to log error
using mce_log. This is because, in multi-node platforms, only the NBC
(Node Base Core, i.e. the first core in the node) has valid status info
in its MCA registers. So, the decoding of status values on the non-NBC
leads to noise on kernel logs like so:
EDAC DEBUG: amd64_inject_write_store: section=0x80000000 word_bits=0x10020001
[Hardware Error]: Corrected error, no action required.
[Hardware Error]: CPU:25 (15:2:0) MC4_STATUS[-|CE|-|-|-
[Hardware Error]: Corrected error, no action required.
[Hardware Error]: CPU:26 (15:2:0) MC4_STATUS[-|CE|-|-|-
<...>
WARNING: CPU: 25 PID: 0 at drivers/edac/amd64_edac.c:2147 decode_bus_error+0x1ba/0x2a0()
WARNING: CPU: 26 PID: 0 at drivers/edac/amd64_edac.c:2147 decode_bus_error+0x1ba/0x2a0()
Something is rotten in the state of Denmark.
Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Aravind Gopalakrishnan <aravind.gopalakrishnan@amd.com>
Link: http://lkml.kernel.org/r/1422896561-7695-1-git-send-email-aravind.gopalakrishnan@amd.com
[ Massage commit message. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
There is another mce_panic call with "Fatal machine check on current CPU" in
the same mce.c file, why not keep them all in same pattern
mce_panic("Fatal machine check on current CPU", &m, msg);
Signed-off-by: Derek Che <drc@yahoo-inc.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Initially, this started with the yet another report about a race
condition in the CMCI storm adaptive period length thing. Yes, we have
to admit, it is fragile and error prone. So let's simplify it.
The simpler logic is: now, after we enter storm mode, we go straight to
polling with CMCI_STORM_INTERVAL, i.e. once a second. We remain in storm
mode as long as we see errors being logged while polling.
Theoretically, if we see an uninterrupted error stream, we will remain
in storm mode indefinitely and keep polling the MSRs.
However, when the storm is actually a burst of errors, once we have
logged them all, we back out of it after ~5 mins of polling and no more
errors logged.
If we encounter an error during those 5 minutes, we reset the polling
interval to 5 mins.
Making machine_check_poll() return a bool and denoting whether it has
seen an error or not lets us simplify a bunch of code and move the storm
handling private to mce_intel.c.
Some minor cleanups while at it.
Reported-by: Calvin Owens <calvinowens@fb.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/1417746575-23299-1-git-send-email-calvinowens@fb.com
Signed-off-by: Borislav Petkov <bp@suse.de>
