28 Sep, 2020
1 commit
-
As SMP-on-UP is a valid configuration on 32bit ARM, do not assume that
IPIs are populated in show_ipi_list().Reported-by: Guillaume Tucker
Reported-by: kernelci.org bot
Tested-by: Guillaume Tucker
Signed-off-by: Marc Zyngier
19 Sep, 2020
1 commit
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ipi_teardown() is only used when CONFIG_HOTPLUG_CPU is enabled.
Move the function to a location guarded by this config option.Signed-off-by: Marc Zyngier
17 Sep, 2020
2 commits
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Let's switch the arm code to the core accounting, which already
does everything we need.Reviewed-by: Valentin Schneider
Signed-off-by: Marc Zyngier -
The old IPI registration interface is now unused on arm, so let's
get rid of it.Reviewed-by: Valentin Schneider
Signed-off-by: Marc Zyngier
14 Sep, 2020
1 commit
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In order to deal with IPIs as normal interrupts, let's add
a new way to register them with the architecture code.set_smp_ipi_range() takes a range of interrupts, and allows
the arch code to request them as if the were normal interrupts.
A standard handler is then called by the core IRQ code to deal
with the IPI.This means that we don't need to call irq_enter/irq_exit, and
that we don't need to deal with set_irq_regs either. So let's
move the dispatcher into its own function, and leave handle_IPI()
as a compatibility function.On the sending side, let's make use of ipi_send_mask, which
already exists for this purpose.One of the major difference is that we end up, in some cases
(such as when performing IRQ time accounting on the scheduler
IPI), end up with nested irq_enter()/irq_exit() pairs.
Other than the (relatively small) overhead, there should be
no consequences to it (these pairs are designed to nest
correctly, and the accounting shouldn't be off).Reviewed-by: Valentin Schneider
Signed-off-by: Marc Zyngier
08 Aug, 2020
1 commit
-
Patch series "mm: cleanup usage of "
Most architectures have very similar versions of pXd_alloc_one() and
pXd_free_one() for intermediate levels of page table. These patches add
generic versions of these functions in and enable
use of the generic functions where appropriate.In addition, functions declared and defined in headers are
used mostly by core mm and early mm initialization in arch and there is no
actual reason to have the included all over the place.
The first patch in this series removes unneeded includes ofIn the end it didn't work out as neatly as I hoped and moving
pXd_alloc_track() definitions to would require
unnecessary changes to arches that have custom page table allocations, so
I've decided to move lib/ioremap.c to mm/ and make pgalloc-track.h local
to mm/.This patch (of 8):
In most cases header is required only for allocations of
page table memory. Most of the .c files that include that header do not
use symbols declared in and do not require that header.As for the other header files that used to include , it is
possible to move that include into the .c file that actually uses symbols
from and drop the include from the header file.The process was somewhat automated using
sed -i -E '/[
Signed-off-by: Andrew Morton
Reviewed-by: Pekka Enberg
Acked-by: Geert Uytterhoeven [m68k]
Cc: Abdul Haleem
Cc: Andy Lutomirski
Cc: Arnd Bergmann
Cc: Christophe Leroy
Cc: Joerg Roedel
Cc: Max Filippov
Cc: Peter Zijlstra
Cc: Satheesh Rajendran
Cc: Stafford Horne
Cc: Stephen Rothwell
Cc: Steven Rostedt
Cc: Joerg Roedel
Cc: Matthew Wilcox
Link: http://lkml.kernel.org/r/20200627143453.31835-1-rppt@kernel.org
Link: http://lkml.kernel.org/r/20200627143453.31835-2-rppt@kernel.org
Signed-off-by: Linus Torvalds
10 Jun, 2020
1 commit
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Patch series "mm: consolidate definitions of page table accessors", v2.
The low level page table accessors (pXY_index(), pXY_offset()) are
duplicated across all architectures and sometimes more than once. For
instance, we have 31 definition of pgd_offset() for 25 supported
architectures.Most of these definitions are actually identical and typically it boils
down to, e.g.static inline unsigned long pmd_index(unsigned long address)
{
return (address >> PMD_SHIFT) & (PTRS_PER_PMD - 1);
}static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address)
{
return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(address);
}These definitions can be shared among 90% of the arches provided
XYZ_SHIFT, PTRS_PER_XYZ and xyz_page_vaddr() are defined.For architectures that really need a custom version there is always
possibility to override the generic version with the usual ifdefs magic.These patches introduce include/linux/pgtable.h that replaces
include/asm-generic/pgtable.h and add the definitions of the page table
accessors to the new header.This patch (of 12):
The linux/mm.h header includes to allow inlining of the
functions involving page table manipulations, e.g. pte_alloc() and
pmd_alloc(). So, there is no point to explicitly include
in the files that include .The include statements in such cases are remove with a simple loop:
for f in $(git grep -l "include ") ; do
sed -i -e '/include / d' $f
doneSigned-off-by: Mike Rapoport
Signed-off-by: Andrew Morton
Cc: Arnd Bergmann
Cc: Borislav Petkov
Cc: Brian Cain
Cc: Catalin Marinas
Cc: Chris Zankel
Cc: "David S. Miller"
Cc: Geert Uytterhoeven
Cc: Greentime Hu
Cc: Greg Ungerer
Cc: Guan Xuetao
Cc: Guo Ren
Cc: Heiko Carstens
Cc: Helge Deller
Cc: Ingo Molnar
Cc: Ley Foon Tan
Cc: Mark Salter
Cc: Matthew Wilcox
Cc: Matt Turner
Cc: Max Filippov
Cc: Michael Ellerman
Cc: Michal Simek
Cc: Mike Rapoport
Cc: Nick Hu
Cc: Paul Walmsley
Cc: Richard Weinberger
Cc: Rich Felker
Cc: Russell King
Cc: Stafford Horne
Cc: Thomas Bogendoerfer
Cc: Thomas Gleixner
Cc: Tony Luck
Cc: Vincent Chen
Cc: Vineet Gupta
Cc: Will Deacon
Cc: Yoshinori Sato
Link: http://lkml.kernel.org/r/20200514170327.31389-1-rppt@kernel.org
Link: http://lkml.kernel.org/r/20200514170327.31389-2-rppt@kernel.org
Signed-off-by: Linus Torvalds
06 Dec, 2019
1 commit
-
Commit ca74b316df96 ("arm: Use common cpu_topology structure and
functions.") changed cpu_coregroup_mask() from the ARM32 specific
implementation in arch/arm/include/asm/topology.h to the one shared
with ARM64 and RISCV in drivers/base/arch_topology.c.Currently on ARM32 (TC2 w/ CONFIG_SCHED_MC) the task scheduler setup
code (w/ CONFIG_SCHED_DEBUG) shows this during CPU hotplug:ERROR: groups don't span domain->span
It happens to CPUs of the cluster of the CPU which gets hot-plugged
out on scheduler domain MC.Turns out that the shared cpu_coregroup_mask() requires that the
hot-plugged CPU is removed from the core_sibling mask via
remove_cpu_topology(). Otherwise the 'is core_sibling subset of
cpumask_of_node()' doesn't work. In this case the task scheduler has to
deal with cpumask_of_node instead of core_sibling which is wrong on
scheduler domain MC.e.g. CPU3 hot-plugged out on TC2 [cluster0: 0,3-4 cluster1: 1-2]:
cpu_coregroup_mask(): CPU3 cpumask_of_node=0-2,4 core_sibling=0,3-4
^
should be:cpu_coregroup_mask(): CPU3 cpumask_of_node=0-2,4 core_sibling=0,4
Add remove_cpu_topology() to __cpu_disable() to remove the CPU from the
topology masks in case of a CPU hotplug out operation.At the same time tweak store_cpu_topology() slightly so it will call
update_siblings_masks() in case of CPU hotplug in operation via
secondary_start_kernel()->smp_store_cpu_info().This aligns the ARM32 implementation with the ARM64 one.
Guarding remove_cpu_topology() with CONFIG_GENERIC_ARCH_TOPOLOGY is
necessary since some Arm32 defconfigs (aspeed_g5_defconfig,
milbeaut_m10v_defconfig, spear13xx_defconfig) specify an explicit# CONFIG_ARM_CPU_TOPOLOGY is not set
w/ ./arch/arm/Kconfig: select GENERIC_ARCH_TOPOLOGY if ARM_CPU_TOPOLOGY
Fixes: ca74b316df96 ("arm: Use common cpu_topology structure and functions")
Reviewed-by: Sudeep Holla
Reviewed-by: Lukasz Luba
Tested-by: Lukasz Luba
Tested-by: Ondrej Jirman
Signed-off-by: Dietmar Eggemann
Signed-off-by: Russell King
13 Aug, 2019
1 commit
-
This commit removes the open-coded CPU-offline notification with new
common code. In particular, this change avoids calling scheduler code
using RCU from an offline CPU that RCU is ignoring. This is a minimal
change. A more intrusive change might invoke the cpu_check_up_prepare()
and cpu_set_state_online() functions at CPU-online time, which would
allow onlining throw an error if the CPU did not go offline properly.Signed-off-by: Paul E. McKenney
Cc: linux-arm-kernel@lists.infradead.org
Cc: Russell King
Cc: Mark Rutland
Cc: Dietmar Eggemann
09 Jul, 2019
1 commit
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Pull ARM updates from Russell King:
- Add a "cut here" to make it clearer where oops dumps should be cut
from - we already have a marker for the end of the dumps.- Add logging severity to show_pte()
- Drop unnecessary common-page-size linker flag
- Errata workarounds for Cortex A12 857271, Cortex A17 857272 and
Cortex A7 814220.- Remove some unused variables that had started to provoke a compiler
warning.* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
ARM: 8863/1: stm32: select ARM errata 814220
ARM: 8862/1: errata: 814220-B-Cache maintenance by set/way operations can execute out of order
ARM: 8865/1: mm: remove unused variables
ARM: 8864/1: Add workaround for I-Cache line size mismatch between CPU cores
ARM: 8861/1: errata: Workaround errata A12 857271 / A17 857272
ARM: 8860/1: VDSO: Drop implicit common-page-size linker flag
ARM: arrange show_pte() to issue severity-based messages
ARM: add "8 to kernel dumps
21 Jun, 2019
1 commit
-
Some big.LITTLE systems have I-Cache line size mismatch between
LITTLE and big cores. This patch adds a workaround for proper I-Cache
support on such systems. Without it, some class of the userspace code
(typically self-modifying) might suffer from random SIGILL failures.Similar workaround already exists for ARM64 architecture. I has been
added by commit 116c81f427ff ("arm64: Work around systems with mismatched
cache line sizes").Signed-off-by: Marek Szyprowski
Signed-off-by: Russell King
19 Jun, 2019
1 commit
-
Based on 2 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundationthis program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 4122 file(s).
Signed-off-by: Thomas Gleixner
Reviewed-by: Enrico Weigelt
Reviewed-by: Kate Stewart
Reviewed-by: Allison Randal
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman
15 May, 2019
2 commits
-
Pull more power management updates from Rafael Wysocki:
"These fix a recent regression causing kernels built with CONFIG_PM
unset to crash on systems that support the Performance and Energy Bias
Hint (EPB), clean up the cpufreq core and some users of transition
notifiers and introduce a new power domain flag into the generic power
domains framework (genpd).Specifics:
- Fix recent regression causing kernels built with CONFIG_PM unset to
crash on systems that support the Performance and Energy Bias Hint
(EPB) by avoiding to compile the EPB-related code depending on
CONFIG_PM when it is unset (Rafael Wysocki).- Clean up the transition notifier invocation code in the cpufreq
core and change some users of cpufreq transition notifiers
accordingly (Viresh Kumar).- Change MAINTAINERS to cover the schedutil governor as part of
cpufreq (Viresh Kumar).- Simplify cpufreq_init_policy() to avoid redundant computations (Yue
Hu).- Add explanatory comment to the cpufreq core (Rafael Wysocki).
- Introduce a new flag, GENPD_FLAG_RPM_ALWAYS_ON, to the generic
power domains (genpd) framework along with the first user of it
(Leonard Crestez)"* tag 'pm-5.2-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
soc: imx: gpc: Use GENPD_FLAG_RPM_ALWAYS_ON for ERR009619
PM / Domains: Add GENPD_FLAG_RPM_ALWAYS_ON flag
cpufreq: Update MAINTAINERS to include schedutil governor
cpufreq: Don't find governor for setpolicy drivers in cpufreq_init_policy()
cpufreq: Explain the kobject_put() in cpufreq_policy_alloc()
cpufreq: Call transition notifier only once for each policy
x86: intel_epb: Take CONFIG_PM into account -
Patch series "compiler: allow all arches to enable
CONFIG_OPTIMIZE_INLINING", v3.This patch (of 11):
When function tracing for IPIs is enabled, we get a warning for an
overflow of the ipi_types array with the IPI_CPU_BACKTRACE type as
triggered by raise_nmi():arch/arm/kernel/smp.c: In function 'raise_nmi':
arch/arm/kernel/smp.c:489:2: error: array subscript is above array bounds [-Werror=array-bounds]
trace_ipi_raise(target, ipi_types[ipinr]);This is a correct warning as we actually overflow the array here.
This patch raise_nmi() to call __smp_cross_call() instead of
smp_cross_call(), to avoid calling into ftrace. For clarification, I'm
also adding a two new code comments describing how this one is special.The warning appears to have shown up after commit e7273ff49acf ("ARM:
8488/1: Make IPI_CPU_BACKTRACE a "non-secure" SGI"), which changed the
number assignment from '15' to '8', but as far as I can tell has existed
since the IPI tracepoints were first introduced. If we decide to
backport this patch to stable kernels, we probably need to backport
e7273ff49acf as well.[yamada.masahiro@socionext.com: rebase on v5.1-rc1]
Link: http://lkml.kernel.org/r/20190423034959.13525-2-yamada.masahiro@socionext.com
Fixes: e7273ff49acf ("ARM: 8488/1: Make IPI_CPU_BACKTRACE a "non-secure" SGI")
Fixes: 365ec7b17327 ("ARM: add IPI tracepoints") # v3.17
Signed-off-by: Arnd Bergmann
Signed-off-by: Masahiro Yamada
Cc: Heiko Carstens
Cc: Arnd Bergmann
Cc: Ingo Molnar
Cc: Christophe Leroy
Cc: Mathieu Malaterre
Cc: "H. Peter Anvin"
Cc: Thomas Gleixner
Cc: Benjamin Herrenschmidt
Cc: Paul Mackerras
Cc: Ralf Baechle
Cc: Stefan Agner
Cc: Boris Brezillon
Cc: Miquel Raynal
Cc: Richard Weinberger
Cc: David Woodhouse
Cc: Brian Norris
Cc: Marek Vasut
Cc: Russell King
Cc: Borislav Petkov
Cc: Mark Rutland
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
10 May, 2019
1 commit
-
Currently, the notifiers are called once for each CPU of the policy->cpus
cpumask. It would be more optimal if the notifier can be called only
once and all the relevant information be provided to it. Out of the 23
drivers that register for the transition notifiers today, only 4 of them
do per-cpu updates and the callback for the rest can be called only once
for the policy without any impact.This would also avoid multiple function calls to the notifier callbacks
and reduce multiple iterations of notifier core's code (which does
locking as well).This patch adds pointer to the cpufreq policy to the struct
cpufreq_freqs, so the notifier callback has all the information
available to it with a single call. The five drivers which perform
per-cpu updates are updated to use the cpufreq policy. The freqs->cpu
field is redundant now and is removed.Acked-by: David S. Miller (sparc)
Signed-off-by: Viresh Kumar
Signed-off-by: Rafael J. Wysocki
15 Mar, 2019
1 commit
02 Feb, 2019
3 commits
-
machine_crash_nonpanic_core() does this:
while (1)
cpu_relax();because the kernel has crashed, and we have no known safe way to deal
with the CPU. So, we place the CPU into an infinite loop which we
expect it to never exit - at least not until the system as a whole is
reset by some method.In the absence of erratum 754327, this code assembles to:
b .
In other words, an infinite loop. When erratum 754327 is enabled,
this becomes:1: dmb
b 1bIt has been observed that on some systems (eg, OMAP4) where, if a
crash is triggered, the system tries to kexec into the panic kernel,
but fails after taking the secondary CPU down - placing it into one
of these loops. This causes the system to livelock, and the most
noticable effect is the system stops after issuing:Loading crashdump kernel...
to the system console.
The tested as working solution I came up with was to add wfe() to
these infinite loops thusly:while (1) {
cpu_relax();
wfe();
}which, without 754327 builds to:
1: wfe
b 1bor with 754327 is enabled:
1: dmb
wfe
b 1bAdding "wfe" does two things depending on the environment we're running
under:
- where we're running on bare metal, and the processor implements
"wfe", it stops us spinning endlessly in a loop where we're never
going to do any useful work.
- if we're running in a VM, it allows the CPU to be given back to the
hypervisor and rescheduled for other purposes (maybe a different VM)
rather than wasting CPU cycles inside a crashed VM.However, in light of erratum 794072, Will Deacon wanted to see 10 nops
as well - which is reasonable to cover the case where we have erratum
754327 enabled _and_ we have a processor that doesn't implement the
wfe hint.So, we now end up with:
1: wfe
b 1bwhen erratum 754327 is disabled, or:
1: dmb
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
wfe
b 1bwhen erratum 754327 is enabled. We also get the dmb + 10 nop
sequence elsewhere in the kernel, in terminating loops.This is reasonable - it means we get the workaround for erratum
794072 when erratum 754327 is enabled, but still relinquish the dead
processor - either by placing it in a lower power mode when wfe is
implemented as such or by returning it to the hypervisior, or in the
case where wfe is a no-op, we use the workaround specified in erratum
794072 to avoid the problem.These as two entirely orthogonal problems - the 10 nops addresses
erratum 794072, and the wfe is an optimisation that makes the system
more efficient when crashed either in terms of power consumption or
by allowing the host/other VMs to make use of the CPU.I don't see any reason not to use kexec() inside a VM - it has the
potential to provide automated recovery from a failure of the VMs
kernel with the opportunity for saving a crashdump of the failure.
A panic() with a reboot timeout won't do that, and reading the
libvirt documentation, setting on_reboot to "preserve" won't either
(the documentation states "The preserve action for an on_reboot event
is treated as a destroy".) Surely it has to be a good thing to
avoiding having CPUs spinning inside a VM that is doing no useful
work.Acked-by: Will Deacon
Signed-off-by: Russell King -
Consolidating the "pen_release" stuff amongst the various SoC
implementations gives credence to having a CPU holding pen for
secondary CPUs. However, this is far from the truth.Many SoC implementations cargo-cult copied various bits of the pen
release implementation from the initial Realview/Versatile Express
implementation without understanding what it was or why it existed.
The reason it existed is because these are _development_ platforms,
and some board firmware is unable to individually control the
startup of secondary CPUs. Moreover, they do not have a way to
power down or reset secondary CPUs for hot-unplug. Hence, the
pen_release implementation was designed for ARM Ltd's development
platforms to provide a working implementation, even though it is
very far from what is required.It was decided a while back to reduce the duplication by consolidating
the "pen_release" variable, but this only made the situation worse -
we have ended up with several implementations that read this variable
but do not write it - again, showing the cargo-cult mentality at work,
lack of proper review of new code, and in some cases a lack of testing.While it would be preferable to remove pen_release entirely from the
kernel, this is not possible without help from the SoC maintainers,
which seems to be lacking. However, I want to remove pen_release from
arch code to remove the credence that having it gives.This patch removes pen_release from the arch code entirely, adding
private per-SoC definitions for it instead, and explicitly stating
that write_pen_release() is cargo-cult copied and should not be
copied any further. Rename write_pen_release() in a similar fashion
as well.Signed-off-by: Russell King
-
Arm TC2 fails cpu hotplug stress test.
This issue was tracked down to a missing copy of the new affinity
cpumask for the vexpress-spc interrupt into struct
irq_common_data.affinity when the interrupt is migrated in
migrate_one_irq().Fix it by replacing the arm specific hotplug cpu migration with the
generic irq code.This is the counterpart implementation to commit 217d453d473c ("arm64:
fix a migrating irq bug when hotplug cpu").Tested with cpu hotplug stress test on Arm TC2 (multi_v7_defconfig plus
CONFIG_ARM_BIG_LITTLE_CPUFREQ=y and CONFIG_ARM_VEXPRESS_SPC_CPUFREQ=y).
The vexpress-spc interrupt (irq=22) on this board is affine to CPU0.
Its affinity cpumask now changes correctly e.g. from 0 to 1-4 when
CPU0 is hotplugged out.Suggested-by: Marc Zyngier
Signed-off-by: Dietmar Eggemann
Acked-by: Marc Zyngier
Reviewed-by: Linus Walleij
Signed-off-by: Russell King
02 Jan, 2019
1 commit
12 Nov, 2018
1 commit
-
In big.Little systems, some CPUs require the Spectre workarounds in
paths such as the context switch, but other CPUs do not. In order
to handle these differences, we need per-CPU vtables.We are unable to use the kernel's per-CPU variables to support this
as per-CPU is not initialised at times when we need access to the
vtables, so we have to use an array indexed by logical CPU number.We use an array-of-pointers to avoid having function pointers in
the kernel's read/write .data section.Reviewed-by: Julien Thierry
Signed-off-by: Russell King
08 Nov, 2018
1 commit
-
In case panic() and panic() called at the same time on different CPUS.
For example:
CPU 0:
panic()
__crash_kexec
machine_crash_shutdown
crash_smp_send_stop
machine_kexec
BUG_ON(num_online_cpus() > 1);CPU 1:
panic()
local_irq_disable
panic_smp_self_stopIf CPU 1 calls panic_smp_self_stop() before crash_smp_send_stop(), kdump
fails. CPU1 can't receive the ipi irq, CPU1 will be always online.
To fix this problem, this patch split out the panic_smp_self_stop()
and add set_cpu_online(smp_processor_id(), false).Signed-off-by: Yufen Wang
Signed-off-by: Russell King
05 Jun, 2018
1 commit
31 May, 2018
1 commit
-
Check for CPU bugs when secondary processors are being brought online,
and also when CPUs are resuming from a low power mode. This gives an
opportunity to check that processor specific bug workarounds are
correctly enabled for all paths that a CPU re-enters the kernel.Signed-off-by: Russell King
Reviewed-by: Florian Fainelli
Boot-tested-by: Tony Lindgren
Reviewed-by: Tony Lindgren
Acked-by: Marc Zyngier
19 May, 2018
1 commit
-
Suspending a CPU on a RT kernel results in the following backtrace:
| Disabling non-boot CPUs ...
| BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917
| in_atomic(): 1, irqs_disabled(): 128, pid: 18, name: migration/1
| INFO: lockdep is turned off.
| irq event stamp: 122
| hardirqs last enabled at (121): [] _raw_spin_unlock_irqrestore+0x88/0x90
| hardirqs last disabled at (122): [] _raw_spin_lock_irq+0x28/0x5c
| CPU: 1 PID: 18 Comm: migration/1 Tainted: G W 4.1.4-rt3-01046-g96ac8da #204
| Hardware name: Generic DRA74X (Flattened Device Tree)
| [] (unwind_backtrace) from [] (show_stack+0x20/0x24)
| [] (show_stack) from [] (dump_stack+0x88/0xdc)
| [] (dump_stack) from [] (___might_sleep+0x198/0x2a8)
| [] (___might_sleep) from [] (rt_spin_lock+0x30/0x70)
| [] (rt_spin_lock) from [] (find_lock_task_mm+0x9c/0x174)
| [] (find_lock_task_mm) from [] (clear_tasks_mm_cpumask+0xb4/0x1ac)
| [] (clear_tasks_mm_cpumask) from [] (__cpu_disable+0x98/0xbc)
| [] (__cpu_disable) from [] (take_cpu_down+0x1c/0x50)
| [] (take_cpu_down) from [] (multi_cpu_stop+0x11c/0x158)
| [] (multi_cpu_stop) from [] (cpu_stopper_thread+0xc4/0x184)
| [] (cpu_stopper_thread) from [] (smpboot_thread_fn+0x18c/0x324)
| [] (smpboot_thread_fn) from [] (kthread+0xe8/0x104)
| [] (kthread) from [] (ret_from_fork+0x14/0x3c)
| CPU1: shutdownThe root cause of above backtrace is task_lock() which takes a sleeping
lock on -RT.To fix the issue, move clear_tasks_mm_cpumask() call from __cpu_disable()
to __cpu_die() which is called on the thread which is asking for a target
CPU to be shutdown. In addition, this change restores CPU hotplug
functionality on ARM CPU1 can be unplugged/plugged many times.Link: http://lkml.kernel.org/r/1441995683-30817-1-git-send-email-grygorii.strashko@ti.com
[bigeasy: slighty edited the commit message]Signed-off-by: Grygorii Strashko
Cc:
Cc: Sekhar Nori
Signed-off-by: Thomas Gleixner
Signed-off-by: Sebastian Andrzej Siewior
Signed-off-by: Russell King
21 Jan, 2018
1 commit
-
With switch to dynamic exception base address setting, VBAR/Hivecs
set only for boot CPU, but secondaries stay unaware of that. That
might lead to weird effects when trying up to bring up secondaries.Fixes: ad475117d201 ("ARM: 8649/2: nommu: remove Hivecs configuration is asm")
Signed-off-by: Vladimir Murzin
Acked-by: afzal mohammed
Signed-off-by: Russell King
23 Oct, 2017
1 commit
-
Currently, there are several issues with how MPU is setup:
1. We won't boot if MPU is missing
2. We won't boot if use XIP
3. Further extension of MPU setup requires asm skillsThe 1st point can be relaxed, so we can continue with boot CPU even if
MPU is missed and fail boot for secondaries only. To address the 2nd
point we could create region covering CONFIG_XIP_PHYS_ADDR - _end and
that might work for the first stage of MPU enable, but due to MPU's
alignment requirement we could cover too much, IOW we need more
flexibility in how we're partitioning memory regions... and it'd be
hardly possible to archive because of the 3rd point.This patch is trying to address 1st and 3rd issues and paves the path
for 2nd and further improvements.The most visible change introduced with this patch is that we start
using mpu_rgn_info array (as it was supposed?), so change in MPU setup
done by boot CPU is recorded there and feed to secondaries. It
allows us to keep minimal region setup for boot CPU and do the rest in
C. Since we start programming MPU regions in C evaluation of MPU
constrains (number of regions supported and minimal region order) can
be done once, which in turn open possibility to free-up "probe"
region early.Tested-by: Szemző András
Tested-by: Alexandre TORGUE
Tested-by: Benjamin Gaignard
Signed-off-by: Vladimir Murzin
Signed-off-by: Russell King
23 May, 2017
1 commit
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To enable smp_processor_id() and might_sleep() debug checks earlier, it's
required to add system states between SYSTEM_BOOTING and SYSTEM_RUNNING.Adjust the system_state check in ipi_cpu_stop() to handle the extra states.
Signed-off-by: Thomas Gleixner
Signed-off-by: Peter Zijlstra (Intel)
Cc: Greg Kroah-Hartman
Cc: Linus Torvalds
Cc: Mark Rutland
Cc: Peter Zijlstra
Cc: Russell King
Cc: Steven Rostedt
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20170516184735.020718977@linutronix.de
Signed-off-by: Ingo Molnar
03 Mar, 2017
1 commit
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Move the following task->mm helper APIs into a new header file,
, to further reduce the size and complexity
of .Here are how the APIs are used in various kernel files:
# mm_alloc():
arch/arm/mach-rpc/ecard.c
fs/exec.c
include/linux/sched/mm.h
kernel/fork.c# __mmdrop():
arch/arc/include/asm/mmu_context.h
include/linux/sched/mm.h
kernel/fork.c# mmdrop():
arch/arm/mach-rpc/ecard.c
arch/m68k/sun3/mmu_emu.c
arch/x86/mm/tlb.c
drivers/gpu/drm/amd/amdkfd/kfd_process.c
drivers/gpu/drm/i915/i915_gem_userptr.c
drivers/infiniband/hw/hfi1/file_ops.c
drivers/vfio/vfio_iommu_spapr_tce.c
fs/exec.c
fs/proc/base.c
fs/proc/task_mmu.c
fs/proc/task_nommu.c
fs/userfaultfd.c
include/linux/mmu_notifier.h
include/linux/sched/mm.h
kernel/fork.c
kernel/futex.c
kernel/sched/core.c
mm/khugepaged.c
mm/ksm.c
mm/mmu_context.c
mm/mmu_notifier.c
mm/oom_kill.c
virt/kvm/kvm_main.c# mmdrop_async_fn():
include/linux/sched/mm.h# mmdrop_async():
include/linux/sched/mm.h
kernel/fork.c# mmget_not_zero():
fs/userfaultfd.c
include/linux/sched/mm.h
mm/oom_kill.c# mmput():
arch/arc/include/asm/mmu_context.h
arch/arc/kernel/troubleshoot.c
arch/frv/mm/mmu-context.c
arch/powerpc/platforms/cell/spufs/context.c
arch/sparc/include/asm/mmu_context_32.h
drivers/android/binder.c
drivers/gpu/drm/etnaviv/etnaviv_gem.c
drivers/gpu/drm/i915/i915_gem_userptr.c
drivers/infiniband/core/umem.c
drivers/infiniband/core/umem_odp.c
drivers/infiniband/core/uverbs_main.c
drivers/infiniband/hw/mlx4/main.c
drivers/infiniband/hw/mlx5/main.c
drivers/infiniband/hw/usnic/usnic_uiom.c
drivers/iommu/amd_iommu_v2.c
drivers/iommu/intel-svm.c
drivers/lguest/lguest_user.c
drivers/misc/cxl/fault.c
drivers/misc/mic/scif/scif_rma.c
drivers/oprofile/buffer_sync.c
drivers/vfio/vfio_iommu_type1.c
drivers/vhost/vhost.c
drivers/xen/gntdev.c
fs/exec.c
fs/proc/array.c
fs/proc/base.c
fs/proc/task_mmu.c
fs/proc/task_nommu.c
fs/userfaultfd.c
include/linux/sched/mm.h
kernel/cpuset.c
kernel/events/core.c
kernel/events/uprobes.c
kernel/exit.c
kernel/fork.c
kernel/ptrace.c
kernel/sys.c
kernel/trace/trace_output.c
kernel/tsacct.c
mm/memcontrol.c
mm/memory.c
mm/mempolicy.c
mm/migrate.c
mm/mmu_notifier.c
mm/nommu.c
mm/oom_kill.c
mm/process_vm_access.c
mm/rmap.c
mm/swapfile.c
mm/util.c
virt/kvm/async_pf.c# mmput_async():
include/linux/sched/mm.h
kernel/fork.c
mm/oom_kill.c# get_task_mm():
arch/arc/kernel/troubleshoot.c
arch/powerpc/platforms/cell/spufs/context.c
drivers/android/binder.c
drivers/gpu/drm/etnaviv/etnaviv_gem.c
drivers/infiniband/core/umem.c
drivers/infiniband/core/umem_odp.c
drivers/infiniband/hw/mlx4/main.c
drivers/infiniband/hw/mlx5/main.c
drivers/infiniband/hw/usnic/usnic_uiom.c
drivers/iommu/amd_iommu_v2.c
drivers/iommu/intel-svm.c
drivers/lguest/lguest_user.c
drivers/misc/cxl/fault.c
drivers/misc/mic/scif/scif_rma.c
drivers/oprofile/buffer_sync.c
drivers/vfio/vfio_iommu_type1.c
drivers/vhost/vhost.c
drivers/xen/gntdev.c
fs/proc/array.c
fs/proc/base.c
fs/proc/task_mmu.c
include/linux/sched/mm.h
kernel/cpuset.c
kernel/events/core.c
kernel/exit.c
kernel/fork.c
kernel/ptrace.c
kernel/sys.c
kernel/trace/trace_output.c
kernel/tsacct.c
mm/memcontrol.c
mm/memory.c
mm/mempolicy.c
mm/migrate.c
mm/mmu_notifier.c
mm/nommu.c
mm/util.c# mm_access():
fs/proc/base.c
include/linux/sched/mm.h
kernel/fork.c
mm/process_vm_access.c# mm_release():
arch/arc/include/asm/mmu_context.h
fs/exec.c
include/linux/sched/mm.h
include/uapi/linux/sched.h
kernel/exit.c
kernel/fork.cAcked-by: Linus Torvalds
Cc: Mike Galbraith
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar
02 Mar, 2017
2 commits
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We are going to split out of , which
will have to be picked up from other headers and a couple of .c files.Create a trivial placeholder file that just
maps to to make this patch obviously correct and
bisectable.Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds
Cc: Mike Galbraith
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar -
We are going to split out of , which
will have to be picked up from other headers and a couple of .c files.Create a trivial placeholder file that just
maps to to make this patch obviously correct and
bisectable.Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds
Cc: Mike Galbraith
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar
01 Mar, 2017
1 commit
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Pull ARM updates from Russell King:
- nommu updates from Afzal Mohammed cleaning up the vectors support
- allow DMA memory "mapping" for nommu Benjamin Gaignard
- fixing a correctness issue with R_ARM_PREL31 relocations in the
module linker- add strlen() prototype for the decompressor
- support for DEBUG_VIRTUAL from Florian Fainelli
- adjusting memory bounds after memory reservations have been
registered- unipher cache handling updates from Masahiro Yamada
- initrd and Thumb Kconfig cleanups
* 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (23 commits)
ARM: mm: round the initrd reservation to page boundaries
ARM: mm: clean up initrd initialisation
ARM: mm: move initrd init code out of arm_memblock_init()
ARM: 8655/1: improve NOMMU definition of pgprot_*()
ARM: 8654/1: decompressor: add strlen prototype
ARM: 8652/1: cache-uniphier: clean up active way setup code
ARM: 8651/1: cache-uniphier: include instead of
ARM: 8650/1: module: handle negative R_ARM_PREL31 addends correctly
ARM: 8649/2: nommu: remove Hivecs configuration is asm
ARM: 8648/2: nommu: display vectors base
ARM: 8647/2: nommu: dynamic exception base address setting
ARM: 8646/1: mmu: decouple VECTORS_BASE from Kconfig
ARM: 8644/1: Reduce "CPU: shutdown" message to debug level
ARM: 8641/1: treewide: Replace uses of virt_to_phys with __pa_symbol
ARM: 8640/1: Add support for CONFIG_DEBUG_VIRTUAL
ARM: 8639/1: Define KERNEL_START and KERNEL_END
ARM: 8638/1: mtd: lart: Rename partition defines to be prefixed with PART_
ARM: 8637/1: Adjust memory boundaries after reservations
ARM: 8636/1: Cleanup sanity_check_meminfo
ARM: add CPU_THUMB_CAPABLE to indicate possible Thumb support
...
28 Feb, 2017
2 commits
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Similar to c68b0274fb3c ("ARM: reduce "Booted secondary processor"
message to debug level"), demote the "CPU: shutdown" pr_notice() into a
pr_debug().Signed-off-by: Florian Fainelli
Signed-off-by: Russell King -
Apart from adding the helper function itself, the rest of the kernel is
converted mechanically using:git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)->mm_count);/mmgrab\(\1\);/'
git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)\.mm_count);/mmgrab\(\&\1\);/'This is needed for a later patch that hooks into the helper, but might
be a worthwhile cleanup on its own.(Michal Hocko provided most of the kerneldoc comment.)
Link: http://lkml.kernel.org/r/20161218123229.22952-1-vegard.nossum@oracle.com
Signed-off-by: Vegard Nossum
Acked-by: Michal Hocko
Acked-by: Peter Zijlstra (Intel)
Acked-by: David Rientjes
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
08 Oct, 2016
2 commits
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Currently on arm there is code that checks whether it should call
dump_stack() explicitly, to avoid trying to raise an NMI when the
current context is not preemptible by the backtrace IPI. Similarly, the
forthcoming arch/tile support uses an IPI mechanism that does not
support generating an NMI to self.Accordingly, move the code that guards this case into the generic
mechanism, and invoke it unconditionally whenever we want a backtrace of
the current cpu. It seems plausible that in all cases, dump_stack()
will generate better information than generating a stack from the NMI
handler. The register state will be missing, but that state is likely
not particularly helpful in any case.Or, if we think it is helpful, we should be capturing and emitting the
current register state in all cases when regs == NULL is passed to
nmi_cpu_backtrace().Link: http://lkml.kernel.org/r/1472487169-14923-3-git-send-email-cmetcalf@mellanox.com
Signed-off-by: Chris Metcalf
Tested-by: Daniel Thompson [arm]
Reviewed-by: Petr Mladek
Acked-by: Aaron Tomlin
Cc: "Rafael J. Wysocki"
Cc: Russell King
Cc: Thomas Gleixner
Cc: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Patch series "improvements to the nmi_backtrace code" v9.
This patch series modifies the trigger_xxx_backtrace() NMI-based remote
backtracing code to make it more flexible, and makes a few small
improvements along the way.The motivation comes from the task isolation code, where there are
scenarios where we want to be able to diagnose a case where some cpu is
about to interrupt a task-isolated cpu. It can be helpful to see both
where the interrupting cpu is, and also an approximation of where the
cpu that is being interrupted is. The nmi_backtrace framework allows us
to discover the stack of the interrupted cpu.I've tested that the change works as desired on tile, and build-tested
x86, arm, mips, and sparc64. For x86 I confirmed that the generic
cpuidle stuff as well as the architecture-specific routines are in the
new cpuidle section. For arm, mips, and sparc I just build-tested it
and made sure the generic cpuidle routines were in the new cpuidle
section, but I didn't attempt to figure out which the platform-specific
idle routines might be. That might be more usefully done by someone
with platform experience in follow-up patches.This patch (of 4):
Currently you can only request a backtrace of either all cpus, or all
cpus but yourself. It can also be helpful to request a remote backtrace
of a single cpu, and since we want that, the logical extension is to
support a cpumask as the underlying primitive.This change modifies the existing lib/nmi_backtrace.c code to take a
cpumask as its basic primitive, and modifies the linux/nmi.h code to use
the new "cpumask" method instead.The existing clients of nmi_backtrace (arm and x86) are converted to
using the new cpumask approach in this change.The other users of the backtracing API (sparc64 and mips) are converted
to use the cpumask approach rather than the all/allbutself approach.
The mips code ignored the "include_self" boolean but with this change it
will now also dump a local backtrace if requested.Link: http://lkml.kernel.org/r/1472487169-14923-2-git-send-email-cmetcalf@mellanox.com
Signed-off-by: Chris Metcalf
Tested-by: Daniel Thompson [arm]
Reviewed-by: Aaron Tomlin
Reviewed-by: Petr Mladek
Cc: "Rafael J. Wysocki"
Cc: Russell King
Cc: Thomas Gleixner
Cc: Ingo Molnar
Cc: Ralf Baechle
Cc: David Miller
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
12 Aug, 2016
1 commit
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Guided by grsecurity's analogous __read_only markings in arch/arm,
this applies several uses of __ro_after_init to structures that are
only updated during __init.Signed-off-by: Kees Cook
Signed-off-by: Russell King
19 Jun, 2016
1 commit
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…t/tmlind/linux-omap into fixes
Fixes for omaps for v4.7-rc cycle:
- Two boot warning fixes from the RCU tree that should have gotten
merged several weeks ago already but did not because of issues
with who merges them. Paul has now split the RCU warning fixes into
sets for various maintainers.- Fix ams-delta FIQ regression caused by omap1 sparse IRQ changes
- Fix PM for omap3 boards using timer12 and gptimer, like the
original beagleboard- Fix hangs on am437x-sk-evm by lowering the I2C bus speed
* tag 'fixes-rcu-fiq-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap:
ARM: dts: am437x-sk-evm: Reduce i2c0 bus speed for tps65218
ARM: OMAP2+: timer: add probe for clocksources
ARM: OMAP1: fix ams-delta FIQ handler to work with sparse IRQ
arm: Use _rcuidle for smp_cross_call() tracepoints
arm: Use _rcuidle tracepoint to allow use from idleSigned-off-by: Olof Johansson <olof@lixom.net>
15 Jun, 2016
1 commit
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Further testing with false negatives suppressed by commit 293e2421fe25
("rcu: Remove superfluous versions of rcu_read_lock_sched_held()")
identified another unprotected use of RCU from the idle loop. Because RCU
actively ignores idle-loop code (for energy-efficiency reasons, among
other things), using RCU from the idle loop can result in too-short
grace periods, in turn resulting in arbitrary misbehavior.The resulting lockdep-RCU splat is as follows:
------------------------------------------------------------------------
===============================
[ INFO: suspicious RCU usage. ]
4.6.0-rc5-next-20160426+ #1112 Not tainted
-------------------------------
include/trace/events/ipi.h:35 suspicious rcu_dereference_check() usage!other info that might help us debug this:
RCU used illegally from idle CPU!
rcu_scheduler_active = 1, debug_locks = 0
RCU used illegally from extended quiescent state!
no locks held by swapper/0/0.stack backtrace:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.6.0-rc5-next-20160426+ #1112
Hardware name: Generic OMAP4 (Flattened Device Tree)
[] (unwind_backtrace) from [] (show_stack+0x10/0x14)
[] (show_stack) from [] (dump_stack+0xb0/0xe4)
[] (dump_stack) from [] (smp_cross_call+0xbc/0x188)
[] (smp_cross_call) from [] (generic_exec_single+0x9c/0x15c)
[] (generic_exec_single) from [] (smp_call_function_single_async+0 x38/0x9c)
[] (smp_call_function_single_async) from [] (cpuidle_coupled_poke_others+0x8c/0xa8)
[] (cpuidle_coupled_poke_others) from [] (cpuidle_enter_state_coupled+0x26c/0x390)
[] (cpuidle_enter_state_coupled) from [] (cpu_startup_entry+0x198/0x3a0)
[] (cpu_startup_entry) from [] (start_kernel+0x354/0x3c8)
[] (start_kernel) from [] (0x8000807c)------------------------------------------------------------------------
Reported-by: Tony Lindgren
Signed-off-by: Paul E. McKenney
Tested-by: Tony Lindgren
Tested-by: Guenter Roeck
Cc: Russell King
Cc: Steven Rostedt
Cc:
Cc:
21 May, 2016
1 commit
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printk() takes some locks and could not be used a safe way in NMI
context.The chance of a deadlock is real especially when printing stacks from
all CPUs. This particular problem has been addressed on x86 by the
commit a9edc8809328 ("x86/nmi: Perform a safe NMI stack trace on all
CPUs").The patchset brings two big advantages. First, it makes the NMI
backtraces safe on all architectures for free. Second, it makes all NMI
messages almost safe on all architectures (the temporary buffer is
limited. We still should keep the number of messages in NMI context at
minimum).Note that there already are several messages printed in NMI context:
WARN_ON(in_nmi()), BUG_ON(in_nmi()), anything being printed out from MCE
handlers. These are not easy to avoid.This patch reuses most of the code and makes it generic. It is useful
for all messages and architectures that support NMI.The alternative printk_func is set when entering and is reseted when
leaving NMI context. It queues IRQ work to copy the messages into the
main ring buffer in a safe context.__printk_nmi_flush() copies all available messages and reset the buffer.
Then we could use a simple cmpxchg operations to get synchronized with
writers. There is also used a spinlock to get synchronized with other
flushers.We do not longer use seq_buf because it depends on external lock. It
would be hard to make all supported operations safe for a lockless use.
It would be confusing and error prone to make only some operations safe.The code is put into separate printk/nmi.c as suggested by Steven
Rostedt. It needs a per-CPU buffer and is compiled only on
architectures that call nmi_enter(). This is achieved by the new
HAVE_NMI Kconfig flag.The are MN10300 and Xtensa architectures. We need to clean up NMI
handling there first. Let's do it separately.The patch is heavily based on the draft from Peter Zijlstra, see
https://lkml.org/lkml/2015/6/10/327
[arnd@arndb.de: printk-nmi: use %zu format string for size_t]
[akpm@linux-foundation.org: min_t->min - all types are size_t here]
Signed-off-by: Petr Mladek
Suggested-by: Peter Zijlstra
Suggested-by: Steven Rostedt
Cc: Jan Kara
Acked-by: Russell King [arm part]
Cc: Daniel Thompson
Cc: Jiri Kosina
Cc: Ingo Molnar
Cc: Thomas Gleixner
Cc: Ralf Baechle
Cc: Benjamin Herrenschmidt
Cc: Martin Schwidefsky
Cc: David Miller
Cc: Daniel Thompson
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
