In preparation for more tk_fast instances, remove all hard-coded
tk_fast_mono references.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150319093400.484279927@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Introduce tkr_raw and make use of it.
base_raw -> tkr_raw.base
clock->{mult,shift} -> tkr_raw.{mult.shift}
Kill timekeeping_get_ns_raw() in favour of
timekeeping_get_ns(&tkr_raw), this removes all mono_raw special
casing.
Duplicate the updates to tkr_mono.cycle_last into tkr_raw.cycle_last,
both need the same value.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150319093400.422589590@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In preparation of adding another tkr field, rename this one to
tkr_mono. Also rename tk_read_base::base_mono to tk_read_base::base,
since the structure is not specific to CLOCK_MONOTONIC and the mono
name got added to the tk_read_base instance.
Lots of trivial churn.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150319093400.344679419@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Trivial cleanups, to improve the readability of the generic sched_clock() code:
- Improve and standardize comments
- Standardize the coding style
- Use vertical spacing where appropriate
- etc.
No code changed:
md5:
19a053b31e0c54feaeff1492012b019a sched_clock.o.before.asm
19a053b31e0c54feaeff1492012b019a sched_clock.o.after.asm
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently it is possible for an NMI (or FIQ on ARM) to come in
and read sched_clock() whilst update_sched_clock() has locked
the seqcount for writing. This results in the NMI handler
locking up when it calls raw_read_seqcount_begin().
This patch fixes the NMI safety issues by providing banked clock
data. This is a similar approach to the one used in Thomas
Gleixner's 4396e058c52e("timekeeping: Provide fast and NMI safe
access to CLOCK_MONOTONIC").
Suggested-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1427397806-20889-6-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently update_sched_clock() is marked as notrace but this
function is not called by ftrace. This is trivially fixed by
removing the mark up.
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1427397806-20889-5-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently cd.read_data.suspended is read by the hotpath function
sched_clock(). This variable need not be accessed on the
hotpath. In fact, once it is removed, we can remove the
conditional branches from sched_clock() and install a dummy
read_sched_clock function to suspend the clock.
The new master copy of the function pointer
(actual_read_sched_clock) is introduced and is used for all
reads of the clock hardware except those within sched_clock
itself.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1427397806-20889-4-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently sched_clock(), a very hot code path, is not optimized
to minimise its cache profile. In particular:
1. cd is not ____cacheline_aligned,
2. struct clock_data does not distinguish between hotpath and
coldpath data, reducing locality of reference in the hotpath,
3. Some hotpath data is missing from struct clock_data and is marked
__read_mostly (which more or less guarantees it will not share a
cache line with cd).
This patch corrects these problems by extracting all hotpath
data into a separate structure and using ____cacheline_aligned
to ensure the hotpath uses a single (64 byte) cache line.
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1427397806-20889-3-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently the scope of the raw_write_seqcount_begin/end() in
sched_clock_register() far exceeds the scope of the read section
in sched_clock(). This gives the impression of safety during
cursory review but achieves little.
Note that this is likely to be a latent issue at present because
sched_clock_register() is typically called before we enable
interrupts, however the issue does risk bugs being needlessly
introduced as the code evolves.
This patch fixes the problem by increasing the scope of the read
locking performed by sched_clock() to cover all data modified by
sched_clock_register.
We also improve clarity by moving writes to struct clock_data
that do not impact sched_clock() outside of the critical
section.
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
[ Reworked it slightly to apply to tip/timers/core]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1427397806-20889-2-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Ingo requested this function be renamed to improve readability,
so I've renamed __clocksource_updatefreq_scale() as well as the
__clocksource_updatefreq_hz/khz() functions to avoid
squishedtogethernames.
This touches some of the sh clocksources, which I've not tested.
The arch/arm/plat-omap change is just a comment change for
consistency.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1426133800-29329-13-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Print the mask, max_cycles, and max_idle_ns values for
clocksources being registered.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1426133800-29329-12-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
A long running project has been to clean up remaining uses
of clocksource_register(), replacing it with the simpler
clocksource_register_khz/hz() functions.
However, there are a few cases where we need to self-define
our mult/shift values, so switch the function to a more
obviously internal __clocksource_register() name, and
consolidate much of the internal logic so we don't have
duplication.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: David S. Miller <davem@davemloft.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1426133800-29329-10-git-send-email-john.stultz@linaro.org
[ Minor cleanups. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The clocksource watchdog reporting has been less helpful
then desired, as it just printed the delta between
the two clocksources. This prevents any useful analysis
of why the skew occurred.
Thus this patch tries to improve the output when we
mark a clocksource as unstable, printing out the cycle
last and now values for both the current clocksource
and the watchdog clocksource. This will allow us to see
if the result was due to a false positive caused by
a problematic watchdog.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1426133800-29329-9-git-send-email-john.stultz@linaro.org
[ Minor cleanups of kernel messages. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
It was suggested that the underflow/overflow protection
should probably throw some sort of warning out, rather
than just silently fixing the issue.
So this patch adds some warnings here. The flag variables
used are not protected by locks, but since we can't print
from the reading functions, just being able to say we
saw an issue in the update interval is useful enough,
and can be slightly racy without real consequence.
The big complication is that we're only under a read
seqlock, so the data could shift under us during
our calculation to see if there was a problem. This
patch avoids this issue by nesting another seqlock
which allows us to snapshot the just required values
atomically. So we shouldn't see false positives.
I also added some basic rate-limiting here, since
on one build machine w/ skewed TSCs it was fairly
noisy at bootup.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1426133800-29329-8-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In the case where there is a broken clocksource
where there are multiple actual clocks that
aren't perfectly aligned, we may see small "negative"
deltas when we subtract 'now' from 'cycle_last'.
The values are actually negative with respect to the
clocksource mask value, not necessarily negative
if cast to a s64, but we can check by checking the
delta to see if it is a small (relative to the mask)
negative value (again negative relative to the mask).
If so, we assume we jumped backwards somehow and
instead use zero for our delta.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1426133800-29329-7-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When calculating the current delta since the last tick, we
currently have no hard protections to prevent a multiplication
overflow from occuring.
This patch introduces infrastructure to allow a cap that
limits the clocksource read delta value to the 'max_cycles' value,
which is where an overflow would occur.
Since this is in the hotpath, it adds the extra checking under
CONFIG_DEBUG_TIMEKEEPING=y.
There was some concern that capping time like this could cause
problems as we may stop expiring timers, which could go circular
if the timer that triggers time accumulation were mis-scheduled
too far in the future, which would cause time to stop.
However, since the mult overflow would result in a smaller time
value, we would effectively have the same problem there.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1426133800-29329-6-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Recently there's been requests for better sanity
checking in the time code, so that it's more clear
when something is going wrong, since timekeeping issues
could manifest in a large number of strange ways in
various subsystems.
Thus, this patch adds some extra infrastructure to
add a check to update_wall_time() to print two new
warnings:
1) if we see the call delayed beyond the 'max_cycles'
overflow point,
2) or if we see the call delayed beyond the clocksource's
'max_idle_ns' value, which is currently 50% of the
overflow point.
This extra infrastructure is conditional on
a new CONFIG_DEBUG_TIMEKEEPING option, also
added in this patch - default off.
Tested this a bit by halting qemu for specified
lengths of time to trigger the warnings.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1426133800-29329-5-git-send-email-john.stultz@linaro.org
[ Improved the changelog and the messages a bit. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In order to facilitate clocksource validation, add a
'max_cycles' field to the clocksource structure which
will hold the maximum cycle value that can safely be
multiplied without potentially causing an overflow.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1426133800-29329-4-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The clocksource logic has a number of places where we try to
include a safety margin. Most of these are 12% safety margins,
but they are inconsistently applied and sometimes are applied
on top of each other.
Additionally, in the previous patch, we corrected an issue
where we unintentionally in effect created a 50% safety margin,
which these 12.5% margins where then added to.
So to simplify the logic here, this patch removes the various
12.5% margins, and consolidates adding the margin in one place:
clocks_calc_max_nsecs().
Additionally, Linus prefers a 50% safety margin, as it allows
bad clock values to be more easily caught. This should really
have no net effect, due to the corrected issue earlier which
caused greater then 50% margins to be used w/o issue.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Acked-by: Stephen Boyd <sboyd@codeaurora.org> (for the sched_clock.c bit)
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1426133800-29329-3-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The previous clocks_calc_max_nsecs() code had some unecessarily
complex bit logic to find the max interval that could cause
multiplication overflows. Since this is not in the hot
path, just do the divide to make it easier to read.
The previous implementation also had a subtle issue
that it avoided overflows with signed 64-bit values, where
as the intervals are always unsigned. This resulted in
overly conservative intervals, which other safety margins
were then added to, reducing the intended interval length.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1426133800-29329-2-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'v4.0-rc2' into timers/core, to refresh the tree before pulling more changes
Pull locking fix from Ingo Molnar:
"An rtmutex deadlock path fixlet"
* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/rtmutex: Set state back to running on error
The "usual" path is:
- rt_mutex_slowlock()
- set_current_state()
- task_blocks_on_rt_mutex() (ret 0)
- __rt_mutex_slowlock()
- sleep or not but do return with __set_current_state(TASK_RUNNING)
- back to caller.
In the early error case where task_blocks_on_rt_mutex() return
-EDEADLK we never change the task's state back to RUNNING. I
assume this is intended. Without this change after ww_mutex
using rt_mutex the selftest passes but later I get plenty of:
| bad: scheduling from the idle thread!
backtraces.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: afffc6c180 ("locking/rtmutex: Optimize setting task running after being blocked")
Link: http://lkml.kernel.org/r/1425056229-22326-4-git-send-email-bigeasy@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There's a uname workaround for broken userspace which can't handle kernel
versions of 3.x. Update it for 4.x.
Signed-off-by: Jon DeVree <nuxi@vault24.org>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull livepatching fixes from Jiri Kosina:
"Two tiny fixes for livepatching infrastructure:
- extending RCU critical section to cover all accessess to
RCU-protected variable, by Petr Mladek
- proper format string passing to kobject_init_and_add(), by Jiri
Kosina"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching:
livepatch: RCU protect struct klp_func all the time when used in klp_ftrace_handler()
livepatch: fix format string in kobject_init_and_add()
func->new_func has been accessed after rcu_read_unlock() in klp_ftrace_handler()
and therefore the access was not protected.
Signed-off-by: Petr Mladek <pmladek@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Pull MIPS updates from Ralf Baechle:
"This is the main pull request for MIPS:
- a number of fixes that didn't make the 3.19 release.
- a number of cleanups.
- preliminary support for Cavium's Octeon 3 SOCs which feature up to
48 MIPS64 R3 cores with FPU and hardware virtualization.
- support for MIPS R6 processors.
Revision 6 of the MIPS architecture is a major revision of the MIPS
architecture which does away with many of original sins of the
architecture such as branch delay slots. This and other changes in
R6 require major changes throughout the entire MIPS core
architecture code and make up for the lion share of this pull
request.
- finally some preparatory work for eXtendend Physical Address
support, which allows support of up to 40 bit of physical address
space on 32 bit processors"
[ Ahh, MIPS can't leave the PAE brain damage alone. It's like
every CPU architect has to make that mistake, but pee in the snow
by changing the TLA. But whether it's called PAE, LPAE or XPA,
it's horrid crud - Linus ]
* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (114 commits)
MIPS: sead3: Corrected get_c0_perfcount_int
MIPS: mm: Remove dead macro definitions
MIPS: OCTEON: irq: add CIB and other fixes
MIPS: OCTEON: Don't do acknowledge operations for level triggered irqs.
MIPS: OCTEON: More OCTEONIII support
MIPS: OCTEON: Remove setting of processor specific CVMCTL icache bits.
MIPS: OCTEON: Core-15169 Workaround and general CVMSEG cleanup.
MIPS: OCTEON: Update octeon-model.h code for new SoCs.
MIPS: OCTEON: Implement DCache errata workaround for all CN6XXX
MIPS: OCTEON: Add little-endian support to asm/octeon/octeon.h
MIPS: OCTEON: Implement the core-16057 workaround
MIPS: OCTEON: Delete unused COP2 saving code
MIPS: OCTEON: Use correct instruction to read 64-bit COP0 register
MIPS: OCTEON: Save and restore CP2 SHA3 state
MIPS: OCTEON: Fix FP context save.
MIPS: OCTEON: Save/Restore wider multiply registers in OCTEON III CPUs
MIPS: boot: Provide more uImage options
MIPS: Remove unneeded #ifdef __KERNEL__ from asm/processor.h
MIPS: ip22-gio: Remove legacy suspend/resume support
mips: pci: Add ifdef around pci_proc_domain
...
Pull ntp fix from Ingo Molnar:
"An adjtimex interface regression fix for 32-bit systems"
[ A check that was added in a previous commit is really only a concern
for 64bit systems, but was applied to both 32 and 64bit systems, which
results in breaking 32bit systems.
Thus the fix here is to make the check only apply to 64bit systems ]
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
ntp: Fixup adjtimex freq validation on 32-bit systems
Pull locking fixes from Ingo Molnar:
"Two fixes: the paravirt spin_unlock() corruption/crash fix, and an
rtmutex NULL dereference crash fix"
* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/spinlocks/paravirt: Fix memory corruption on unlock
locking/rtmutex: Avoid a NULL pointer dereference on deadlock
Pull scheduler fixes from Ingo Molnar:
"Thiscontains misc fixes: preempt_schedule_common() and io_schedule()
recursion fixes, sched/dl fixes, a completion_done() revert, two
sched/rt fixes and a comment update patch"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/rt: Avoid obvious configuration fail
sched/autogroup: Fix failure to set cpu.rt_runtime_us
sched/dl: Do update_rq_clock() in yield_task_dl()
sched: Prevent recursion in io_schedule()
sched/completion: Serialize completion_done() with complete()
sched: Fix preempt_schedule_common() triggering tracing recursion
sched/dl: Prevent enqueue of a sleeping task in dl_task_timer()
sched: Make dl_task_time() use task_rq_lock()
sched: Clarify ordering between task_rq_lock() and move_queued_task()
Pull rcu fix and x86 irq fix from Ingo Molnar:
- Fix a bug that caused an RCU warning splat.
- Two x86 irq related fixes: a hotplug crash fix and an ACPI IRQ
registry fix.
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
rcu: Clear need_qs flag to prevent splat
* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/irq: Check for valid irq descriptor in check_irq_vectors_for_cpu_disable()
x86/irq: Fix regression caused by commit b568b8601f
* KDB: improved searching
* No longer enter debug core on panic if panic timeout is set
KGDB/KDB regressions / cleanups
* fix pdf doc build errors
* prevent junk characters on kdb console from printk levels
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Merge tag 'for_linux-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb
Pull kgdb/kdb updates from Jason Wessel:
"KGDB/KDB New:
- KDB: improved searching
- No longer enter debug core on panic if panic timeout is set
KGDB/KDB regressions / cleanups
- fix pdf doc build errors
- prevent junk characters on kdb console from printk levels"
* tag 'for_linux-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb:
kgdb, docs: Fix <para> pdfdocs build errors
debug: prevent entering debug mode on panic/exception.
kdb: Const qualifier for kdb_getstr's prompt argument
kdb: Provide forward search at more prompt
kdb: Fix a prompt management bug when using | grep
kdb: Remove stack dump when entering kgdb due to NMI
kdb: Avoid printing KERN_ levels to consoles
kdb: Fix off by one error in kdb_cpu()
kdb: fix incorrect counts in KDB summary command output
On non-developer devices, kgdb prevents the device from rebooting
after a panic.
Incase of panics and exceptions, to allow the device to reboot, prevent
entering debug mode to avoid getting stuck waiting for the user to
interact with debugger.
To avoid entering the debugger on panic/exception without any extra
configuration, panic_timeout is being used which can be set via
/proc/sys/kernel/panic at run time and CONFIG_PANIC_TIMEOUT sets the
default value.
Setting panic_timeout indicates that the user requested machine to
perform unattended reboot after panic. We dont want to get stuck waiting
for the user input incase of panic.
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: kgdb-bugreport@lists.sourceforge.net
Cc: linux-kernel@vger.kernel.org
Cc: Android Kernel Team <kernel-team@android.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Colin Cross <ccross@android.com>
[Kiran: Added context to commit message.
panic_timeout is used instead of break_on_panic and
break_on_exception to honor CONFIG_PANIC_TIMEOUT
Modified the commit as per community feedback]
Signed-off-by: Kiran Raparthy <kiran.kumar@linaro.org>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
All current callers of kdb_getstr() can pass constant pointers via the
prompt argument. This patch adds a const qualification to make explicit
the fact that this is safe.
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Currently kdb allows the output of comamnds to be filtered using the
| grep feature. This is useful but does not permit the output emitted
shortly after a string match to be examined without wading through the
entire unfiltered output of the command. Such a feature is particularly
useful to navigate function traces because these traces often have a
useful trigger string *before* the point of interest.
This patch reuses the existing filtering logic to introduce a simple
forward search to kdb that can be triggered from the more prompt.
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Currently when the "| grep" feature is used to filter the output of a
command then the prompt is not displayed for the subsequent command.
Likewise any characters typed by the user are also not echoed to the
display. This rather disconcerting problem eventually corrects itself
when the user presses Enter and the kdb_grepping_flag is cleared as
kdb_parse() tries to make sense of whatever they typed.
This patch resolves the problem by moving the clearing of this flag
from the middle of command processing to the beginning.
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Issuing a stack dump feels ergonomically wrong when entering due to NMI.
Entering due to NMI is normally a reaction to a user request, either the
NMI button on a server or a "magic knock" on a UART. Therefore the
backtrace behaviour on entry due to NMI should be like SysRq-g (no stack
dump) rather than like oops.
Note also that the stack dump does not offer any information that
cannot be trivial retrieved using the 'bt' command.
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Currently when kdb traps printk messages then the raw log level prefix
(consisting of '\001' followed by a numeral) does not get stripped off
before the message is issued to the various I/O handlers supported by
kdb. This causes annoying visual noise as well as causing problems
grepping for ^. It is also a change of behaviour compared to normal usage
of printk() usage. For example <SysRq>-h ends up with different output to
that of kdb's "sr h".
This patch addresses the problem by stripping log levels from messages
before they are issued to the I/O handlers. printk() which can also
act as an i/o handler in some cases is special cased; if the caller
provided a log level then the prefix will be preserved when sent to
printk().
The addition of non-printable characters to the output of kdb commands is a
regression, albeit and extremely elderly one, introduced by commit
04d2c8c83d ("printk: convert the format for KERN_<LEVEL> to a 2 byte
pattern"). Note also that this patch does *not* restore the original
behaviour from v3.5. Instead it makes printk() from within a kdb command
display the message without any prefix (i.e. like printk() normally does).
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Joe Perches <joe@perches.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
There was a follow on replacement patch against the prior
"kgdb: Timeout if secondary CPUs ignore the roundup".
See: https://lkml.org/lkml/2015/1/7/442
This patch is the delta vs the patch that was committed upstream:
* Fix an off-by-one error in kdb_cpu().
* Replace NR_CPUS with CONFIG_NR_CPUS to tell checkpatch that we
really want a static limit.
* Removed the "KGDB: " prefix from the pr_crit() in debug_core.c
(kgdb-next contains a patch which introduced pr_fmt() to this file
to the tag will now be applied automatically).
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
The output of KDB 'summary' command should report MemTotal, MemFree
and Buffers output in kB. Current codes report in unit of pages.
A define of K(x) as
is defined in the code, but not used.
This patch would apply the define to convert the values to kB.
Please include me on Cc on replies. I do not subscribe to linux-kernel.
Signed-off-by: Jay Lan <jlan@sgi.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Pull kbuild updates from Michal Marek:
- several cleanups in kbuild
- serialize multiple *config targets so that 'make defconfig kvmconfig'
works
- The cc-ifversion macro got support for an else-branch
* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
kbuild,gcov: simplify kernel/gcov/Makefile more
kbuild: allow cc-ifversion to have the argument for false condition
kbuild,gcov: simplify kernel/gcov/Makefile
kbuild,gcov: remove unnecessary workaround
kbuild: do not add $(call ...) to invoke cc-version or cc-fullversion
kbuild: fix cc-ifversion macro
kbuild: drop $(version_h) from MRPROPER_FILES
kbuild: use mixed-targets when two or more config targets are given
kbuild: remove redundant line from bounds.h/asm-offsets.h
kbuild: merge bounds.h and asm-offsets.h rules
kbuild: Drop support for clean-rule
Setting the root group's cpu.rt_runtime_us to 0 is a bad thing; it
would disallow the kernel creating RT tasks.
One can of course still set it to 1, which will (likely) still wreck
your kernel, but at least make it clear that setting it to 0 is not
good.
Collect both sanity checks into the one place while we're there.
Suggested-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20150209112715.GO24151@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Because task_group() uses a cache of autogroup_task_group(), whose
output depends on sched_class, switching classes can generate
problems.
In particular, when started as fair, the cache points to the
autogroup, so when switching to RT the tg_rt_schedulable() test fails
for every cpu.rt_{runtime,period}_us change because now the autogroup
has tasks and no runtime.
Furthermore, going back to the previous semantics of varying
task_group() with sched_class has the down-side that the sched_debug
output varies as well, even though the task really is in the
autogroup.
Therefore add an autogroup exception to tg_has_rt_tasks() -- such that
both (all) task_group() usages in sched/core now have one. And remove
all the remnants of the variable task_group() output.
Reported-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Stefan Bader <stefan.bader@canonical.com>
Fixes: 8323f26ce3 ("sched: Fix race in task_group()")
Link: http://lkml.kernel.org/r/20150209112237.GR5029@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
It is not possible for the clockevents core to know which modes (other than
those with a corresponding feature flag) are supported by a particular
implementation. And drivers are expected to handle transition to all modes
elegantly, as ->set_mode() would be issued for them unconditionally.
Now, adding support for a new mode complicates things a bit if we want to use
the legacy ->set_mode() callback. We need to closely review all clockevents
drivers to see if they would break on addition of a new mode. And after such
reviews, it is found that we have to do non-trivial changes to most of the
drivers [1].
Introduce mode-specific set_mode_*() callbacks, some of which the drivers may or
may not implement. A missing callback would clearly convey the message that the
corresponding mode isn't supported.
A driver may still choose to keep supporting the legacy ->set_mode() callback,
but ->set_mode() wouldn't be supporting any new modes beyond RESUME. If a driver
wants to benefit from using a new mode, it would be required to migrate to
the mode specific callbacks.
The legacy ->set_mode() callback and the newly introduced mode-specific
callbacks are mutually exclusive. Only one of them should be supported by the
driver.
Sanity check is done at the time of registration to distinguish between optional
and required callbacks and to make error recovery and handling simpler. If the
legacy ->set_mode() callback is provided, all mode specific ones would be
ignored by the core but a warning is thrown if they are present.
Call sites calling ->set_mode() directly are also updated to use
__clockevents_set_mode() instead, as ->set_mode() may not be available anymore
for few drivers.
[1] https://lkml.org/lkml/2014/12/9/605
[2] https://lkml.org/lkml/2015/1/23/255
Suggested-by: Thomas Gleixner <tglx@linutronix.de> [2]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: linaro-kernel@lists.linaro.org
Cc: linaro-networking@linaro.org
Link: http://lkml.kernel.org/r/792d59a40423f0acffc9bb0bec9de1341a06fa02.1423788565.git.viresh.kumar@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Additional validation of adjtimex freq values to avoid
potential multiplication overflows were added in commit
5e5aeb4367 (time: adjtimex: Validate the ADJ_FREQUENCY values)
Unfortunately the patch used LONG_MAX/MIN instead of
LLONG_MAX/MIN, which was fine on 64-bit systems, but being
much smaller on 32-bit systems caused false positives
resulting in most direct frequency adjustments to fail w/
EINVAL.
ntpd only does direct frequency adjustments at startup, so
the issue was not as easily observed there, but other time
sync applications like ptpd and chrony were more effected by
the bug.
See bugs:
https://bugzilla.kernel.org/show_bug.cgi?id=92481https://bugzilla.redhat.com/show_bug.cgi?id=1188074
This patch changes the checks to use LLONG_MAX for
clarity, and additionally the checks are disabled
on 32-bit systems since LLONG_MAX/PPM_SCALE is always
larger then the 32-bit long freq value, so multiplication
overflows aren't possible there.
Reported-by: Josh Boyer <jwboyer@fedoraproject.org>
Reported-by: George Joseph <george.joseph@fairview5.com>
Tested-by: George Joseph <george.joseph@fairview5.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org> # v3.19+
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Link: http://lkml.kernel.org/r/1423553436-29747-1-git-send-email-john.stultz@linaro.org
[ Prettified the changelog and the comments a bit. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
io_schedule() calls blk_flush_plug() which, depending on the
contents of current->plug, can initiate arbitrary blk-io requests.
Note that this contrasts with blk_schedule_flush_plug() which requires
all non-trivial work to be handed off to a separate thread.
This makes it possible for io_schedule() to recurse, and initiating
block requests could possibly call mempool_alloc() which, in times of
memory pressure, uses io_schedule().
Apart from any stack usage issues, io_schedule() will not behave
correctly when called recursively as delayacct_blkio_start() does
not allow for repeated calls.
So:
- use ->in_iowait to detect recursion. Set it earlier, and restore
it to the old value.
- move the call to "raw_rq" after the call to blk_flush_plug().
As this is some sort of per-cpu thing, we want some chance that
we are on the right CPU
- When io_schedule() is called recurively, use blk_schedule_flush_plug()
which cannot further recurse.
- as this makes io_schedule() a lot more complex and as io_schedule()
must match io_schedule_timeout(), but all the changes in io_schedule_timeout()
and make io_schedule a simple wrapper for that.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
[ Moved the now rudimentary io_schedule() into sched.h. ]
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Tony Battersby <tonyb@cybernetics.com>
Link: http://lkml.kernel.org/r/20150213162600.059fffb2@notabene.brown
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit de30ec4730 "Remove unnecessary ->wait.lock serialization when
reading completion state" was not correct, without lock/unlock the code
like stop_machine_from_inactive_cpu()
while (!completion_done())
cpu_relax();
can return before complete() finishes its spin_unlock() which writes to
this memory. And spin_unlock_wait().
While at it, change try_wait_for_completion() to use READ_ONCE().
Reported-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reported-by: Davidlohr Bueso <dave@stgolabs.net>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
[ Added a comment with the barrier. ]
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nicholas Mc Guire <der.herr@hofr.at>
Cc: raghavendra.kt@linux.vnet.ibm.com
Cc: waiman.long@hp.com
Fixes: de30ec4730 ("sched/completion: Remove unnecessary ->wait.lock serialization when reading completion state")
Link: http://lkml.kernel.org/r/20150212195913.GA30430@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Since the function graph tracer needs to disable preemption, it might
call preempt_schedule() after reenabling it if something triggered the
need for rescheduling in between.
Therefore we can't trace preempt_schedule() itself because we would
face a function tracing recursion otherwise as the tracer is always
called before PREEMPT_ACTIVE gets set to prevent that recursion. This is
why preempt_schedule() is tagged as "notrace".
But the same issue applies to every function called by preempt_schedule()
before PREEMPT_ACTIVE is actually set. And preempt_schedule_common() is
one such example. Unfortunately we forgot to tag it as notrace as well
and as a result we are encountering tracing recursion since it got
introduced by:
a18b5d0181 ("sched: Fix missing preemption opportunity")
Let's fix that by applying the appropriate function tag to
preempt_schedule_common().
Reported-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1424110807-15057-1-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
