If jump target is outside of function range, perf is not handling it
correctly. Especially when target address is lesser than function start
address, target offset will be negative. But, target address declared to
be unsigned, converts negative number into 2's complement. See below
example. Here target of 'jumpq' instruction at 34cf8 is 34ac0 which is
lesser than function start address(34cf0).
34ac0 - 34cf0 = -0x230 = 0xfffffffffffffdd0
Objdump output:
0000000000034cf0 <__sigaction>:
__GI___sigaction():
34cf0: lea -0x20(%rdi),%eax
34cf3: cmp -bashx1,%eax
34cf6: jbe 34d00 <__sigaction+0x10>
34cf8: jmpq 34ac0 <__GI___libc_sigaction>
34cfd: nopl (%rax)
34d00: mov 0x386161(%rip),%rax # 3bae68 <_DYNAMIC+0x2e8>
34d07: movl -bashx16,%fs:(%rax)
34d0e: mov -bashxffffffff,%eax
34d13: retq
perf annotate before applying patch:
__GI___sigaction /usr/lib64/libc-2.22.so
lea -0x20(%rdi),%eax
cmp -bashx1,%eax
v jbe 10
v jmpq fffffffffffffdd0
nop
10: mov _DYNAMIC+0x2e8,%rax
movl -bashx16,%fs:(%rax)
mov -bashxffffffff,%eax
retq
perf annotate after applying patch:
__GI___sigaction /usr/lib64/libc-2.22.so
lea -0x20(%rdi),%eax
cmp -bashx1,%eax
v jbe 10
^ jmpq 34ac0 <__GI___libc_sigaction>
nop
10: mov _DYNAMIC+0x2e8,%rax
movl -bashx16,%fs:(%rax)
mov -bashxffffffff,%eax
retq
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Chris Riyder <chris.ryder@arm.com>
Cc: Kim Phillips <kim.phillips@arm.com>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Taeung Song <treeze.taeung@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1480953407-7605-3-git-send-email-ravi.bangoria@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Architectures like PowerPC have jump instructions that includes a target
address as a second operand. For example, 'bne cr7,0xc0000000000f6154'.
Add support for such instruction in perf annotate.
objdump o/p:
c0000000000f6140: ld r9,1032(r31)
c0000000000f6144: cmpdi cr7,r9,0
c0000000000f6148: bne cr7,0xc0000000000f6154
c0000000000f614c: ld r9,2312(r30)
c0000000000f6150: std r9,1032(r31)
c0000000000f6154: ld r9,88(r31)
Corresponding perf annotate o/p:
Before patch:
ld r9,1032(r31)
cmpdi cr7,r9,0
v bne 3ffffffffff09f2c
ld r9,2312(r30)
std r9,1032(r31)
74: ld r9,88(r31)
After patch:
ld r9,1032(r31)
cmpdi cr7,r9,0
v bne 74
ld r9,2312(r30)
std r9,1032(r31)
74: ld r9,88(r31)
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Chris Riyder <chris.ryder@arm.com>
Cc: Kim Phillips <kim.phillips@arm.com>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Taeung Song <treeze.taeung@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1480953407-7605-2-git-send-email-ravi.bangoria@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Enable perf_evsel::ignore_missing_thread for -u option to ignore
complete failure if any of the user's processes die between its
enumeration and time we open the event.
Committer notes:
While doing a 'make -j4 allmodconfig' we sometimes get into the race:
Before:
# perf record -u acme
Error:
The sys_perf_event_open() syscall returned with 3 (No such process) for event (cycles:ppp).
/bin/dmesg may provide additional information.
No CONFIG_PERF_EVENTS=y kernel support configured?
#
After:
[root@jouet ~]# perf record -u acme
WARNING: Ignored open failure for pid 9888
WARNING: Ignored open failure for pid 18059
[root@jouet ~]#
Which is an improvement, with the races not preventing the remaining threads
for the specified user from being monitored, but the message probably needs
further clarification.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1481538943-21874-6-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Adding perf_evsel::ignore_missing_cpu_thread bool.
When set true, it allows perf to ignore error of missing pid of perf
event syscall.
We remove missing thread id from the thread_map, so the rest of the
processing like ioctl and mmap won't get disturbed with -1 fd.
The reason for supporting this is to ease up monitoring group of pids,
that 'disappear' before perf opens their event. This currently leads
perf to report error and exit and makes perf record's -u option unusable
under certain setup.
With this change we will allow this race and ignore such failure with
following warning:
WARNING: Ignored open failure for pid 8605
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20161213074622.GA3084@krava
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
It's more readable and will ease up following patches.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1481538943-21874-3-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
I.e. those parameters/functions _are_ used, so ditch that misleading attribute.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-13cqtjh0yojg5gzvpq1zzpl0@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The --idle-hist option is to analyze system idle state so which process
makes cpu to go idle. If this option is specified, non-idle events will
be skipped and processes switching to/from idle will be shown.
This option is mostly useful when used with --summary(-only) option. In
the idle-time summary view, idle time is accounted to previous thread
which is run before idle task.
The example output looks like following:
Idle-time summary
comm parent sched-out idle-time min-idle avg-idle max-idle stddev migrations
(count) (msec) (msec) (msec) (msec) %
--------------------------------------------------------------------------------------------
rcu_preempt[7] 2 95 550.872 0.011 5.798 23.146 7.63 0
migration/1[16] 2 1 15.558 15.558 15.558 15.558 0.00 0
khugepaged[39] 2 1 3.062 3.062 3.062 3.062 0.00 0
kworker/0:1H[124] 2 2 4.728 0.611 2.364 4.116 74.12 0
systemd-journal[167] 1 1 4.510 4.510 4.510 4.510 0.00 0
kworker/u16:3[558] 2 13 74.737 0.080 5.749 12.960 21.96 0
irq/34-iwlwifi[628] 2 21 118.403 0.032 5.638 23.990 24.00 0
kworker/u17:0[673] 2 1 3.523 3.523 3.523 3.523 0.00 0
dbus-daemon[722] 1 1 6.743 6.743 6.743 6.743 0.00 0
ifplugd[741] 1 1 58.826 58.826 58.826 58.826 0.00 0
wpa_supplicant[1490] 1 1 13.302 13.302 13.302 13.302 0.00 0
wpa_actiond[1492] 1 2 4.064 0.168 2.032 3.896 91.72 0
dockerd[1500] 1 1 0.055 0.055 0.055 0.055 0.00 0
...
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20161208144755.16673-6-namhyung@kernel.org
Link: http://lkml.kernel.org/r/20161213080632.19099-2-namhyung@kernel.org
[ Merged fix sent by Namhyumg, as posted in the second Link: tag ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Sometimes it only focuses on idle-related events like upcoming idle-hist
feature. In this case we don't want to see other event to reduce noise.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20161208144755.16673-5-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
In order to investigate the idleness reason, it is necessary to keep the
callchains when entering idle. This can be identified by the
sched:sched_switch event having the next_pid field as 0.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20161208144755.16673-4-namhyung@kernel.org
Link: http://lkml.kernel.org/r/20161213080632.19099-1-namhyung@kernel.org
[ Merged fix from Namhyung, see second Link: tag ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The struct idle_time_data is to keep idle stats with callchains entering
to the idle task. The normal thread_runtime calculation is done
transparently since it extends the struct thread_runtime.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20161208144755.16673-3-namhyung@kernel.org
[ Align struct field names ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The is_idle_sample() function actually does more than determining
whether sample come from idle task. Split the callchain part into
save_task_callchain() to make it clearer.
Also checking prev_pid from trace data looks preferred than just
checking sample->pid since it's possible, although rare, to have invalid
0 pid/tid on scheduling an exiting task.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20161208144755.16673-2-namhyung@kernel.org
[ Remove some needless () in some return statements ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
To make it nicer and easily maintainable.
Also moving the check into fixdep sub make, so its output is not
scattered around the build output.
Removing extra $$ from mman*.h checks.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1481030331-31944-5-git-send-email-jolsa@kernel.org
[ Use /bin/sh, and 'function check() {' -> 'check () {' to make it work with busybox, in Alpine Linux, for instance ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Update the MAINTAINERS file for AFS and AF_RXRPC to include a website
pointer.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[ This resurrects commit 53855d10f4, which was reverted in
2b41226b39. It depended on commit d544abd5ff ("lib/radix-tree:
Convert to hotplug state machine") so now it is correct to apply ]
Patch "lib/radix-tree: Convert to hotplug state machine" breaks the test
suite as it adds a call to cpuhp_setup_state_nocalls() which is not
currently emulated in the test suite. Add it, and delete the emulation
of the old CPU hotplug mechanism.
Link: http://lkml.kernel.org/r/1480369871-5271-36-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If CONFIG_PRINTK=n:
kernel/printk/printk.c:1893: warning: ‘cont’ defined but not used
Note that there are actually two different struct cont definitions and
objects: the first one is used if CONFIG_PRINTK=y, the second one became
unused by removing console_cont_flush().
Fixes: 5c2992ee7f ("printk: remove console flushing special cases for partial buffered lines")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Petr Mladek <pmladek@suse.com>
[ I do the occasional "allnoconfig" builds, but apparently not often
enough - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add example 64MByte long reservation in the first 512MBytes of physical
memory used as shared DMA pool.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Enable HAVE_DMA_CONTIGUOUS, reserve contiguous memory at bootmem_init,
use dma_alloc_from_contiguous and dma_release_from_contiguous in
xtensa_dma_alloc/free.
This allows for big contiguous DMA buffer allocation from designated
area configured in the device tree.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Don't free the cmd in tcmu_check_expired_cmd, it's still referenced by
an entry in our cmd_id->cmd idr. If userspace ever resumes processing,
tcmu_handle_completions() will use the now-invalid cmd pointer.
Instead, don't free cmd. It will be freed by tcmu_handle_completion() if
userspace ever recovers, or tcmu_free_device if not.
Cc: stable@vger.kernel.org
Reported-by: Bryant G Ly <bgly@us.ibm.com>
Tested-by: Bryant G Ly <bgly@us.ibm.com>
Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
When the operand passed to VMPTRLD matches the address of the VMXON
region, the VMX instruction error code should be
VMXERR_VMPTRLD_VMXON_POINTER rather than VMXERR_VMCLEAR_VMXON_POINTER.
Signed-off-by: GanShun <ganshun@google.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Since commit af2cf278ef ("x86/mm/hotplug: Don't remove PGD entries in
remove_pagetable()") there are no callers of sync_global_pgds() which set
the 'removed' argument to 1.
Remove the argument and the related conditionals in the function.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Link: http://lkml.kernel.org/r/20161214234403.137556-1-kirill.shutemov@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Commit 34c3d9819f ("genirq/affinity: Provide smarter irq spreading
infrastructure") introduced a better IRQ spreading mechanism, taking
account of the available NUMA nodes in the machine.
Problem is that the algorithm of retrieving the nodemask iterates
"linearly" based on the number of online nodes - some architectures
present non-linear node distribution among the nodemask, like PowerPC.
If this is the case, the algorithm lead to a wrong node count number
and therefore to a bad/incomplete IRQ affinity distribution.
For example, this problem were found in a machine with 128 CPUs and two
nodes, namely nodes 0 and 8 (instead of 0 and 1, if it was linearly
distributed). This led to a wrong affinity distribution which then led to
a bad mq allocation for nvme driver.
Finally, we take the opportunity to fix a comment regarding the affinity
distribution when we have _more_ nodes than vectors.
Fixes: 34c3d9819f ("genirq/affinity: Provide smarter irq spreading infrastructure")
Reported-by: Gabriel Krisman Bertazi <gabriel@krisman.be>
Signed-off-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Gabriel Krisman Bertazi <gabriel@krisman.be>
Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Cc: linux-pci@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: hch@lst.de
Link: http://lkml.kernel.org/r/1481738472-2671-1-git-send-email-gpiccoli@linux.vnet.ibm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
When a disfunctional timer, e.g. dummy timer, is installed, the tick core
tries to setup the broadcast timer.
If no broadcast device is installed, the kernel crashes with a NULL pointer
dereference in tick_broadcast_setup_oneshot() because the function has no
sanity check.
Reported-by: Mason <slash.tmp@free.fr>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Richard Cochran <rcochran@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Cc: Sebastian Frias <sf84@laposte.net>
Cc: Thibaud Cornic <thibaud_cornic@sigmadesigns.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Link: http://lkml.kernel.org/r/1147ef90-7877-e4d2-bb2b-5c4fa8d3144b@free.fr
When the dummy timer callback is invoked before the real timer callbacks,
then it tries to install that timer for the starting CPU. If the platform
does not have a broadcast timer installed the installation fails with a
kernel crash. The crash happens due to a unconditional deference of the non
available broadcast device. This needs to be fixed in the timer core code.
But even when this is fixed in the core code then installing the dummy
timer before the real timers is a pointless exercise.
Move it to the end of the callback list.
Fixes: 00c1d17aab ("clocksource/dummy_timer: Convert to hotplug state machine")
Reported-and-tested-by: Mason <slash.tmp@free.fr>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Richard Cochran <rcochran@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Cc: Sebastian Frias <sf84@laposte.net>
Cc: Thibaud Cornic <thibaud_cornic@sigmadesigns.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Link: http://lkml.kernel.org/r/1147ef90-7877-e4d2-bb2b-5c4fa8d3144b@free.fr
Add a description of the HW_EVENT_ERR_DEFERRED type that wasn't included
with commit d12a969ebb ("EDAC, amd64: Add Deferred Error type").
Signed-off-by: Yazen Ghannam <Yazen.Ghannam@amd.com>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Instead of storing the concepts dictionary inside header file,
move it to the subsystem documentation.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
As this file was never added to the driver-api, the kernel-doc
markups there were never tested. Some of them have issues.
Fix them.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Some kernel-doc tags don't provide good descriptions or use
a different style. Adjust them.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Update MAINTAINERS to reflect the location of edac.rst and ras.rst.
In the case of 00-INDEX, there's already an entry to the admin-guide,
so all we need to do is to remove the entry there.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Currently, there's no device driver documentation for the EDAC
subsystem at the driver-api book. Fill in the blanks for the
structures and functions that misses documentation, uniform
the word on the existing ones, and add a new edac.rst file at
driver-api, in order to document the EDAC subsystem.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Several functions are documented at edac_mc.c.
As we'll be including edac_core.h at drivers-api book, move
those, in order for the kernel-doc markups be part of the API
documentation book.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Several functions are documented at edac_pci.c and edac_pci_sysfs.c.
As we'll be including edac_pci.h at drivers-api book, move those,
in order for the kernel-doc markups be part of the API
documentation book.
As several of those kernel-doc macros are not in the right format,
fix them.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Several functions are documented at edac_device.c.
As we'll be including edac_core.h at drivers-api book, move those,
in order for the kernel-doc markups be part of the API
documentation book.
As several of those kernel-doc macros are not in the right format,
fix them.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
The edac_core.h header contain data structures and function
definitions for both EDAC MC and EDAC device.
Let's move the devices ones to a separate header file, as part
of a header reorganization.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
The edac_core.h header contain data structures and function
definitions for the 3 parts of EDAC: MC, PCI and device.
Let's move the PCI ones to a separate header file, as part
of a header reorganization.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
EDAC is part of the Kernel's RAS facilities, with is useful for
system admins to detect errors. So, add it to the admin's guide.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
The edac.txt assumes that the reader has already deep knowledge
on RAS features. However, this may not be the case. So, add an
introduction chapter explaining the main concepts that are used by
the EDAC subsystem and by other RAS drivers within the Kernel.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
There's a chapter at edac.rst written by the time Nehalem
support was added. Such information is used not only by the
Nehalem driver (i7core_edac), but by all newer Intel CPU
architectures that are supported by i7core_edac, sb_edac
and sbx_edac drivers.
Update the information to reflect that.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
This driver has been there for almost 3 years, without any
conceptual changes. So, it is not experimental anymore, and
won't likely have any changes at the API or on log outputs.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Converts the EDAC driver subsystem documentation to ReST:
- Put paragraph titles in lower case;
- Add code blocks where needed;
- Convert tables to ReST markup;
- Mark filesystem and module names as verbatim;
- Adjust document to be properly displayed in html.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Documentation for those are missing at the EDAC description.
I guess we end by moving such descriptions in the past to the
ABI document (or only added it there), but it means that the
EDAC documentation is incomplete. So, add it there.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Roland reported that his DELL T5810 sports a value add BIOS which
completely wreckages the TSC. The squirmware [(TM) Ingo Molnar] boots with
random negative TSC_ADJUST values, different on all CPUs. That renders the
TSC useless because the sycnchronization check fails.
Roland tested the new TSC_ADJUST mechanism. While it manages to readjust
the TSCs he needs to disable the TSC deadline timer, otherwise the machine
just stops booting.
Deeper investigation unearthed that the TSC deadline timer is sensitive to
the TSC_ADJUST value. Writing TSC_ADJUST to a negative value results in an
interrupt storm caused by the TSC deadline timer.
This does not make any sense and it's hard to imagine what kind of hardware
wreckage is behind that misfeature, but it's reliably reproducible on other
systems which have TSC_ADJUST and TSC deadline timer.
While it would be understandable that a big enough negative value which
moves the resulting TSC readout into the negative space could have the
described effect, this happens even with a adjust value of -1, which keeps
the TSC readout definitely in the positive space. The compare register for
the TSC deadline timer is set to a positive value larger than the TSC, but
despite not having reached the deadline the interrupt is raised
immediately. If this happens on the boot CPU, then the machine dies
silently because this setup happens before the NMI watchdog is armed.
Further experiments showed that any other adjustment of TSC_ADJUST works as
expected as long as it stays in the positive range. The direction of the
adjustment has no influence either. See the lkml link for further analysis.
Yet another proof for the theory that timers are designed by janitors and
the underlying (obviously undocumented) mechanisms which allow BIOSes to
wreckage them are considered a feature. Well done Intel - NOT!
To address this wreckage add the following sanity measures:
- If the TSC_ADJUST value on the boot cpu is not 0, set it to 0
- If the TSC_ADJUST value on any cpu is negative, set it to 0
- Prevent the cross package synchronization mechanism from setting negative
TSC_ADJUST values.
Reported-and-tested-by: Roland Scheidegger <rscheidegger_lists@hispeed.ch>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Bruce Schlobohm <bruce.schlobohm@intel.com>
Cc: Kevin Stanton <kevin.b.stanton@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Allen Hung <allen_hung@dell.com>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20161213131211.397588033@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
