The __IRQF_TIMER bit from the flags argument was used in
add_interrupt_randomness() to distinguish the timer interrupt from other
interrupts. This is no longer the case.
Remove the flags argument from __handle_irq_event_percpu().
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Several architectures select GENERIC_IRQ_MULTI_HANDLER and branch to
handle_arch_irq() without performing any entry accounting.
Add a generic wrapper to handle the common irqentry work when invoking
handle_arch_irq(). Where an architecture needs to perform some entry
accounting itself, it will need to invoke handle_arch_irq() itself.
In subsequent patches it will become the responsibilty of the entry code
to set the irq regs when entering an IRQ (rather than deferring this to
an irqchip handler), so generic_handle_arch_irq() is made to set the irq
regs now. This can be redundant in some cases, but is never harmful as
saving/restoring the old regs nests safely.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Guo Ren <guoren@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
The whole call to note_interrupt() can be avoided or return early when
interrupts would be marked accordingly. For IPI handlers which always
return HANDLED the whole procedure is pretty pointless to begin with.
Add a IRQF_NO_DEBUG flag and mark the interrupt accordingly if supplied
when the interrupt is requested.
When noirqdebug is set on the kernel commandline, then the interrupt is
marked unconditionally so that there is only one condition in the hotpath
to evaluate.
[ clg: Add changelog ]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/7a8ad02f-63a8-c1aa-fdd1-39d973593d02@kaod.org
Pull x86 entry code updates from Thomas Gleixner:
- Convert the 32bit syscalls to be pt_regs based which removes the
requirement to push all 6 potential arguments onto the stack and
consolidates the interface with the 64bit variant
- The first small portion of the exception and syscall related entry
code consolidation which aims to address the recently discovered
issues vs. RCU, int3, NMI and some other exceptions which can
interrupt any context. The bulk of the changes is still work in
progress and aimed for 5.8.
- A few lockdep namespace cleanups which have been applied into this
branch to keep the prerequisites for the ongoing work confined.
* tag 'x86-entry-2020-03-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (35 commits)
x86/entry: Fix build error x86 with !CONFIG_POSIX_TIMERS
lockdep: Rename trace_{hard,soft}{irq_context,irqs_enabled}()
lockdep: Rename trace_softirqs_{on,off}()
lockdep: Rename trace_hardirq_{enter,exit}()
x86/entry: Rename ___preempt_schedule
x86: Remove unneeded includes
x86/entry: Drop asmlinkage from syscalls
x86/entry/32: Enable pt_regs based syscalls
x86/entry/32: Use IA32-specific wrappers for syscalls taking 64-bit arguments
x86/entry/32: Rename 32-bit specific syscalls
x86/entry/32: Clean up syscall_32.tbl
x86/entry: Remove ABI prefixes from functions in syscall tables
x86/entry/64: Add __SYSCALL_COMMON()
x86/entry: Remove syscall qualifier support
x86/entry/64: Remove ptregs qualifier from syscall table
x86/entry: Move max syscall number calculation to syscallhdr.sh
x86/entry/64: Split X32 syscall table into its own file
x86/entry/64: Move sys_ni_syscall stub to common.c
x86/entry/64: Use syscall wrappers for x32_rt_sigreturn
x86/entry: Refactor SYS_NI macros
...
Extend lockdep to validate lock wait-type context.
The current wait-types are:
LD_WAIT_FREE, /* wait free, rcu etc.. */
LD_WAIT_SPIN, /* spin loops, raw_spinlock_t etc.. */
LD_WAIT_CONFIG, /* CONFIG_PREEMPT_LOCK, spinlock_t etc.. */
LD_WAIT_SLEEP, /* sleeping locks, mutex_t etc.. */
Where lockdep validates that the current lock (the one being acquired)
fits in the current wait-context (as generated by the held stack).
This ensures that there is no attempt to acquire mutexes while holding
spinlocks, to acquire spinlocks while holding raw_spinlocks and so on. In
other words, its a more fancy might_sleep().
Obviously RCU made the entire ordeal more complex than a simple single
value test because RCU can be acquired in (pretty much) any context and
while it presents a context to nested locks it is not the same as it
got acquired in.
Therefore its necessary to split the wait_type into two values, one
representing the acquire (outer) and one representing the nested context
(inner). For most 'normal' locks these two are the same.
[ To make static initialization easier we have the rule that:
.outer == INV means .outer == .inner; because INV == 0. ]
It further means that its required to find the minimal .inner of the held
stack to compare against the outer of the new lock; because while 'normal'
RCU presents a CONFIG type to nested locks, if it is taken while already
holding a SPIN type it obviously doesn't relax the rules.
Below is an example output generated by the trivial test code:
raw_spin_lock(&foo);
spin_lock(&bar);
spin_unlock(&bar);
raw_spin_unlock(&foo);
[ BUG: Invalid wait context ]
-----------------------------
swapper/0/1 is trying to lock:
ffffc90000013f20 (&bar){....}-{3:3}, at: kernel_init+0xdb/0x187
other info that might help us debug this:
1 lock held by swapper/0/1:
#0: ffffc90000013ee0 (&foo){+.+.}-{2:2}, at: kernel_init+0xd1/0x187
The way to read it is to look at the new -{n,m} part in the lock
description; -{3:3} for the attempted lock, and try and match that up to
the held locks, which in this case is the one: -{2,2}.
This tells that the acquiring lock requires a more relaxed environment than
presented by the lock stack.
Currently only the normal locks and RCU are converted, the rest of the
lockdep users defaults to .inner = INV which is ignored. More conversions
can be done when desired.
The check for spinlock_t nesting is not enabled by default. It's a separate
config option for now as there are known problems which are currently
addressed. The config option allows to identify these problems and to
verify that the solutions found are indeed solving them.
The config switch will be removed and the checks will permanently enabled
once the vast majority of issues has been addressed.
[ bigeasy: Move LD_WAIT_FREE,… out of CONFIG_LOCKDEP to avoid compile
failure with CONFIG_DEBUG_SPINLOCK + !CONFIG_LOCKDEP]
[ tglx: Add the config option ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200321113242.427089655@linutronix.de
There is a plan to build the kernel with -Wimplicit-fallthrough. The
fallthrough in __handle_irq_event_percpu() has a fallthrough annotation
which is followed by an additional comment and is not recognized by GCC.
Separate the 'fall through' and the rest of the comment with a dash so the
regular expression used by GCC matches.
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190114203633.18557-1-malat@debian.org
Add SPDX identifiers to files
- which contain an explicit license boiler plate or reference
- which do not contain a license reference and were not updated in the
initial SPDX conversion because the license was deduced by the scanners
via EXPORT_SYMBOL_GPL as GPL2.0 only.
[ tglx: Moved adding identifiers from the patch which removes the
references/boilerplate ]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Link: https://lkml.kernel.org/r/20180314212030.668321222@linutronix.de
Pull documentation updates from Jonathan Corbet:
"There has been a fair amount of activity in the docs tree this time
around. Highlights include:
- Conversion of a bunch of security documentation into RST
- The conversion of the remaining DocBook templates by The Amazing
Mauro Machine. We can now drop the entire DocBook build chain.
- The usual collection of fixes and minor updates"
* tag 'docs-4.13' of git://git.lwn.net/linux: (90 commits)
scripts/kernel-doc: handle DECLARE_HASHTABLE
Documentation: atomic_ops.txt is core-api/atomic_ops.rst
Docs: clean up some DocBook loose ends
Make the main documentation title less Geocities
Docs: Use kernel-figure in vidioc-g-selection.rst
Docs: fix table problems in ras.rst
Docs: Fix breakage with Sphinx 1.5 and upper
Docs: Include the Latex "ifthen" package
doc/kokr/howto: Only send regression fixes after -rc1
docs-rst: fix broken links to dynamic-debug-howto in kernel-parameters
doc: Document suitability of IBM Verse for kernel development
Doc: fix a markup error in coding-style.rst
docs: driver-api: i2c: remove some outdated information
Documentation: DMA API: fix a typo in a function name
Docs: Insert missing space to separate link from text
doc/ko_KR/memory-barriers: Update control-dependencies example
Documentation, kbuild: fix typo "minimun" -> "minimum"
docs: Fix some formatting issues in request-key.rst
doc: ReSTify keys-trusted-encrypted.txt
doc: ReSTify keys-request-key.txt
...
The interrupt framework gives a lot of information about each interrupt. It
does not keep track of when those interrupts occur though, which is a
prerequisite for estimating the next interrupt arrival for power management
purposes.
Add a mechanism to record the timestamp for each interrupt occurrences in a
per-CPU circular buffer to help with the prediction of the next occurrence
using a statistical model.
Each CPU can store up to IRQ_TIMINGS_SIZE events <irq, timestamp>, the
current value of IRQ_TIMINGS_SIZE is 32.
Each event is encoded into a single u64, where the high 48 bits are used
for the timestamp and the low 16 bits are for the irq number.
A static key is introduced so when the irq prediction is switched off at
runtime, the overhead is near to zero.
It results in most of the code in internals.h for inline reasons and a very
few in the new file timings.c. The latter will contain more in the next patch
which will provide the statistical model for the next event prediction.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: "Rafael J . Wysocki" <rafael@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Link: http://lkml.kernel.org/r/1498227072-5980-1-git-send-email-daniel.lezcano@linaro.org
This book got converted from DocBook. Update its references to
point to the current location.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
This adds a software irq handler for controllers that multiplex
interrupts from multiple devices, but don't know which device generated
the interrupt. For these devices, the irq handler that demuxes must
check every action for every software irq using the same h/w irq in order
to find out which device generated the interrupt. This will inevitably
trigger spurious interrupt detection if we are noting the irq.
The new irq handler does not track the handling for spurious interrupt
detection. An irq that uses this also won't get stats tracked since it
didn't generate the interrupt, nor added to randomness since they are
not random.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org
Cc: Jon Derrick <jonathan.derrick@intel.com>
Link: http://lkml.kernel.org/r/1466200821-29159-1-git-send-email-keith.busch@intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The irq code browses the list of actions differently to inspect the element
one by one. Even if it is not a problem, for the sake of consistent code,
provide a macro similar to for_each_irq_desc in order to have the same loop to
go through the actions list and use it in the code.
[ tglx: Renamed the macro ]
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: http://lkml.kernel.org/r/1452765253-31148-1-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
commit 71f64340fc changed the handling of irq_desc->action from
CPU 0 CPU 1
free_irq() lock(desc)
lock(desc) handle_edge_irq()
if (desc->action) {
handle_irq_event()
action = desc->action
unlock(desc)
desc->action = NULL handle_irq_event_percpu(desc, action)
action->xxx
to
CPU 0 CPU 1
free_irq() lock(desc)
lock(desc) handle_edge_irq()
if (desc->action) {
handle_irq_event()
unlock(desc)
desc->action = NULL handle_irq_event_percpu(desc, action)
action = desc->action
action->xxx
So if free_irq manages to set the action to NULL between the unlock and before
the readout, we happily dereference a null pointer.
We could simply revert 71f64340fc, but we want to preserve the better code
generation. A simple solution is to change the action loop from a do {} while
to a while {} loop.
This is safe because we either see a valid desc->action or NULL. If the action
is about to be removed it is still valid as free_irq() is blocked on
synchronize_irq().
CPU 0 CPU 1
free_irq() lock(desc)
lock(desc) handle_edge_irq()
handle_irq_event(desc)
set(INPROGRESS)
unlock(desc)
handle_irq_event_percpu(desc)
action = desc->action
desc->action = NULL while (action) {
action->xxx
...
action = action->next;
sychronize_irq()
while(INPROGRESS); lock(desc)
clr(INPROGRESS)
free(action)
That's basically the same mechanism as we have for shared
interrupts. action->next can become NULL while handle_irq_event_percpu()
runs. Either it sees the action or NULL. It does not matter, because action
itself cannot go away before the interrupt in progress flag has been cleared.
Fixes: commit 71f64340fc "genirq: Remove the second parameter from handle_irq_event_percpu()"
Reported-by: zyjzyj2000@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Huang Shijie <shijie.huang@arm.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1601131224190.3575@nanos
Most interrupt flow handlers do not use the irq argument. Those few
which use it can retrieve the irq number from the irq descriptor.
Remove the argument.
Search and replace was done with coccinelle and some extra helper
scripts around it. Thanks to Julia for her help!
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Sebastian Andrzej Siewior
Mark Rutland
Thomas Gleixner
Gustavo A. R. Silva
Linus Torvalds
Peter Zijlstra
Sakari Ailus
Mathieu Malaterre
Palmer Dabbelt
Daniel Lezcano
Mauro Carvalho Chehab
Keith Busch
Arnd Bergmann
Huang Shijie
Jiang Liu