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 <cmetcalf@mellanox.com>
Tested-by: Daniel Thompson <daniel.thompson@linaro.org> [arm]
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Aaron Tomlin <atomlin@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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 <cmetcalf@mellanox.com>
Tested-by: Daniel Thompson <daniel.thompson@linaro.org> [arm]
Reviewed-by: Aaron Tomlin <atomlin@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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 <keescook@chromium.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
- 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
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Merge tag 'fixes-rcu-fiq-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/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 idle
Signed-off-by: Olof Johansson <olof@lixom.net>
Further testing with false negatives suppressed by commit 293e2421fe
("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)
[<c0110308>] (unwind_backtrace) from [<c010c3a8>] (show_stack+0x10/0x14)
[<c010c3a8>] (show_stack) from [<c047fec8>] (dump_stack+0xb0/0xe4)
[<c047fec8>] (dump_stack) from [<c010dcfc>] (smp_cross_call+0xbc/0x188)
[<c010dcfc>] (smp_cross_call) from [<c01c9e28>] (generic_exec_single+0x9c/0x15c)
[<c01c9e28>] (generic_exec_single) from [<c01ca0a0>] (smp_call_function_single_async+0 x38/0x9c)
[<c01ca0a0>] (smp_call_function_single_async) from [<c0603728>] (cpuidle_coupled_poke_others+0x8c/0xa8)
[<c0603728>] (cpuidle_coupled_poke_others) from [<c0603c10>] (cpuidle_enter_state_coupled+0x26c/0x390)
[<c0603c10>] (cpuidle_enter_state_coupled) from [<c0183c74>] (cpu_startup_entry+0x198/0x3a0)
[<c0183c74>] (cpu_startup_entry) from [<c0b00c0c>] (start_kernel+0x354/0x3c8)
[<c0b00c0c>] (start_kernel) from [<8000807c>] (0x8000807c)
------------------------------------------------------------------------
Reported-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: <linux-omap@vger.kernel.org>
Cc: <linux-arm-kernel@lists.infradead.org>
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 a9edc88093 ("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 <pmladek@suse.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Jan Kara <jack@suse.cz>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> [arm part]
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jiri Kosina <jkosina@suse.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: David Miller <davem@davemloft.net>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Let the non boot cpus call into idle with the corresponding hotplug state, so
the hotplug core can handle the further bringup. That's a first step to
convert the boot side of the hotplugged cpus to do all the synchronization
with the other side through the state machine. For now it'll only start the
hotplug thread and kick the full bringup of the cpu.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: Rik van Riel <riel@redhat.com>
Cc: Rafael Wysocki <rafael.j.wysocki@intel.com>
Cc: "Srivatsa S. Bhat" <srivatsa@mit.edu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Turner <pjt@google.com>
Link: http://lkml.kernel.org/r/20160226182341.614102639@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Having IPI_CPU_BACKTRACE as SGI15 may not work if the kernel is
running in non-secure mode and that the secure firmware has
decided to follow ARM's recommendations that SGI8-15 should
be reserved for secure purpose.
Now that we are "only" using SGI0-6, change IPI_CPU_BACKTRACE
to use SGI7, which makes it more likely to work.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Since 9a46ad6d6d ("smp: make smp_call_function_many() use logic
similar to smp_call_function_single()"), the core IPI handling
has been simplified, and generic_smp_call_function_interrupt is
now the same as generic_smp_call_function_single_interrupt.
This means that one of IPI_CALL_FUNC and IPI_CALL_FUNC_SINGLE has
become redundant. We can then safely drop IPI_CALL_FUNC_SINGLE,
and use only IPI_CALL_FUNC.
This has the advantage of reducing the number of SGI IDs we're using
(a fairly scarse resource).
Tested on a dual A7 board.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Currently on ARM when <SysRq-L> is triggered from an interrupt handler
(e.g. a SysRq issued using UART or kbd) the main CPU will wedge for ten
seconds with interrupts masked before issuing a backtrace for every CPU
except itself.
The new backtrace code introduced by commit 96f0e00378 ("ARM: add
basic support for on-demand backtrace of other CPUs") does not work
correctly when run from an interrupt handler because IPI_CPU_BACKTRACE
is used to generate the backtrace on all CPUs but cannot preempt the
current calling context.
This can be fixed by detecting that the calling context cannot be
preempted and issuing the backtrace directly in this case. Issuing
directly leaves us without any pt_regs to pass to nmi_cpu_backtrace()
so we also modify the generic code to call dump_stack() when its
argument is NULL.
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This function just copies '*ops' to 'smp_ops', so the given
structure '*ops' is not modified at all.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch adds imprecise abort enable/disable macros and uses them to
enable imprecise aborts early when starting the kernel.
This helps in tracking down the real cause for such imprecise abort, as
they are handled as soon as they occur. Until now those aborts would
only be enabled when entering the userspace and as a consequence crash
the first userspace process if any abort had been raised during kernel
startup.
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Pull NMI backtrace update from Russell King:
"These changes convert the x86 NMI handling to be a library
implementation which other architectures can make use of. Thomas
Gleixner has reviewed and tested these changes, and wishes me to send
these rather than taking them through the tip tree.
The final patch in the set adds an initial implementation using this
infrastructure to ARM, even though it doesn't send the IPI at "NMI"
level. Patches are in progress to add the ARM equivalent of NMI, but
we still need the IRQ-level fallback for systems where the "NMI" isn't
available due to secure firmware denying access to it"
* 'nmi' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
ARM: add basic support for on-demand backtrace of other CPUs
nmi: x86: convert to generic nmi handler
nmi: create generic NMI backtrace implementation
The only caller of cpu_die() on ARM is arch_cpu_idle_dead(), so
let's simplify the code by renaming cpu_die() to
arch_cpu_idle_dead(). While were here, drop the __ref annotation
because __cpuinit is gone nowadays.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Writes to /sys/.../cpuX/online fail if we determine the platform
doesn't support hotplug for that CPU. Furthermore, if the cpu_die
op isn't specified the system hangs when we try to offline a CPU
and it comes right back online unexpectedly. Let's figure this
stuff out before we make the sysfs nodes so that the online file
doesn't even exist if it isn't (at least sometimes) possible to
hotplug the CPU.
Add a new 'cpu_can_disable' op and repoint all 'cpu_disable'
implementations at it because all implementers use the op to
indicate if a CPU can be hotplugged or not in a static fashion.
With PSCI we may need to add a 'cpu_disable' op so that the
secure OS can be migrated off the CPU we're trying to hotplug.
In this case, the 'cpu_can_disable' op will indicate that all
CPUs are hotpluggable by returning true, but the 'cpu_disable' op
will make a PSCI migration call and occasionally fail, denying
the hotplug of a CPU. This shouldn't be any worse than x86 where
we may indicate that all CPUs are hotpluggable but occasionally
we can't offline a CPU due to check_irq_vectors_for_cpu_disable()
failing to find a CPU to move vectors to.
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Dave Martin <Dave.Martin@arm.com>
Acked-by: Simon Horman <horms@verge.net.au> [shmobile portion]
Tested-by: Simon Horman <horms@verge.net.au>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: <linux-sh@vger.kernel.org>
Tested-by: Tyler Baker <tyler.baker@linaro.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
As we now have generic infrastructure to support backtracing of other
CPUs in the system on lockups, we can start to implement this for ARM.
Initially, we add an IPI based implementation, as the GIC code needs
modification to support the generation of FIQ IPIs, and not all ARM
platforms have the ability to raise a FIQ in the non-secure world.
This provides us with a "best efforts" implementation in the absence
of FIQs.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
John Stultz reports an RCU splat on boot with ARM ipi trace
events enabled.
===============================
[ INFO: suspicious RCU usage. ]
4.1.0-rc7-00033-gb5bed2f #153 Not tainted
-------------------------------
include/trace/events/ipi.h:68 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 4.1.0-rc7-00033-gb5bed2f #153
Hardware name: Qualcomm (Flattened Device Tree)
[<c0216b08>] (unwind_backtrace) from [<c02136e8>] (show_stack+0x10/0x14)
[<c02136e8>] (show_stack) from [<c075e678>] (dump_stack+0x70/0xbc)
[<c075e678>] (dump_stack) from [<c0215a80>] (handle_IPI+0x428/0x604)
[<c0215a80>] (handle_IPI) from [<c020942c>] (gic_handle_irq+0x54/0x5c)
[<c020942c>] (gic_handle_irq) from [<c0766604>] (__irq_svc+0x44/0x7c)
Exception stack(0xc09f3f48 to 0xc09f3f90)
3f40: 00000001 00000001 00000000 c09f73b8 c09f4528 c0a5de9c
3f60: c076b4f0 00000000 00000000 c09ef108 c0a5cec1 00000001 00000000 c09f3f90
3f80: c026bf60 c0210ab8 20000113 ffffffff
[<c0766604>] (__irq_svc) from [<c0210ab8>] (arch_cpu_idle+0x20/0x3c)
[<c0210ab8>] (arch_cpu_idle) from [<c02647f0>] (cpu_startup_entry+0x2c0/0x5dc)
[<c02647f0>] (cpu_startup_entry) from [<c099bc1c>] (start_kernel+0x358/0x3c4)
[<c099bc1c>] (start_kernel) from [<8020807c>] (0x8020807c)
At this point in the IPI handling path we haven't called
irq_enter() yet, so RCU doesn't know that we're about to exit
idle and properly warns that we're using RCU from an idle CPU.
Use trace_ipi_entry_rcuidle() instead of trace_ipi_entry() so
that RCU is informed about our exit from idle.
Fixes: 365ec7b173 ("ARM: add IPI tracepoints")
Reported-by: John Stultz <john.stultz@linaro.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Re-engineer the LPAE TTBR setup code. Rather than passing some shifted
address in order to fit in a CPU register, pass either a full physical
address (in the case of r4, r5 for TTBR0) or a PFN (for TTBR1).
This removes the ARCH_PGD_SHIFT hack, and the last dangerous user of
cpu_set_ttbr() in the secondary CPU startup code path (which was there
to re-set TTBR1 to the appropriate high physical address space on
Keystone2.)
Tested-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
When trying to kexec into a new kernel on a platform where multiple CPU
cores are present, but no SMP bringup code is available yet, the
kexec_load system call fails with:
kexec_load failed: Invalid argument
The SMP test added to machine_kexec_prepare() in commit 2103f6cba6
("ARM: 7807/1: kexec: validate CPU hotplug support") wants to prohibit
kexec on SMP platforms where it cannot disable secondary CPUs.
However, this test is too strict: if the secondary CPUs couldn't be
enabled in the first place, there's no need to disable them later at
kexec time. Hence skip the test in the absence of SMP bringup code.
This allows to add all CPU cores to the DTS from the beginning, without
having to implement SMP bringup first, improving DT compatibility.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The "SMP: Total of %d processors activated." message which we print in
smp_cpus_done() provides no further information than the message in
genreic code in smp_announce(). Kill it.
Tested-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Drop the "CPUn: Booted secondary processor" message from info to debug
level. We later print how many CPUs came online, so listing each one
is redundant, and when using hotplug, can be quite noisy.
Tested-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Convert many (but not all) printk(KERN_* to pr_* to simplify the code.
We take the opportunity to join some printk lines together so we don't
split the message across several lines, and we also add a few levels
to some messages which were previously missing them.
Tested-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Pull timer fixes from Ingo Molnar:
"Main changes:
- Fix the deadlock reported by Dave Jones et al
- Clean up and fix nohz_full interaction with arch abilities
- nohz init code consolidation/cleanup"
* 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
nohz: nohz full depends on irq work self IPI support
nohz: Consolidate nohz full init code
arm64: Tell irq work about self IPI support
arm: Tell irq work about self IPI support
x86: Tell irq work about self IPI support
irq_work: Force raised irq work to run on irq work interrupt
irq_work: Introduce arch_irq_work_has_interrupt()
nohz: Move nohz full init call to tick init
Use the more common pr_warn.
Other miscellanea:
o Coalesce formats
o Realign arguments
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM irq work IPI support depends on SMP support. That information is
partly known at early boottime. Lets implement
arch_irq_work_has_interrupt() accordingly.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
After becoming a mandatory function, boot_secondary() is no longer used
outside arch/arm/kernel/smp.c. Hence remove its public prototype, and,
as suggested by Arnd, let it be absorbed by its single caller.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The strings used to list IPIs in /proc/interrupts are reused for tracing
purposes.
While at it, prevent a negative ipinr from escaping the range check
in handle_IPI().
Link: http://lkml.kernel.org/p/1406318733-26754-4-git-send-email-nicolas.pitre@linaro.org
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Two cpufreq notifiers CPUFREQ_RESUMECHANGE and CPUFREQ_SUSPENDCHANGE have
not been used for some time, so remove them to clean up code a bit.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
[rjw: Changelog]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Although we allow recovery in this case, this is not supposed to be
the normal path for hotplugging a CPU back in. This path only exists
to serve those rare platforms where it's not possible to power down
the CPU or reset the CPU. This patch causes the kernel to print a
message when a platform uses this path.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
We have a handy macro to replace open coded __cpuc_flush_dcache_area(()
and outer_clean_range() sequences. Let's use it. No functional change.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
By default, IRQ work is run from the tick interrupt (see
irq_work_run() in update_process_times()). When we're in full
NOHZ mode, restarting the tick requires the use of IRQ work and
if the only place we run IRQ work is in the tick interrupt we
have an unbreakable cycle. Implement arch_irq_work_raise() via
self IPIs to break this cycle and get the tick started again.
Note that we implement this via IPIs which are only available on
SMP builds. This shouldn't be a problem because full NOHZ is only
supported on SMP builds anyway.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Reviewed-by: Kevin Hilman <khilman@linaro.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
On some PAE systems (e.g. TI Keystone), memory is above the
32-bit addressable limit, and the interconnect provides an
aliased view of parts of physical memory in the 32-bit addressable
space. This alias is strictly for boot time usage, and is not
otherwise usable because of coherency limitations. On such systems,
the idmap mechanism needs to take this aliased mapping into account.
This patch introduces virt_to_idmap() and a arch function pointer which
can be populated by platform which needs it. Also populate necessary
idmap spots with now available virt_to_idmap(). Avoided #ifdef approach
to be compatible with multi-platform builds.
Most architecture won't touch it and in that case virt_to_idmap()
fall-back to existing virt_to_phys() macro.
Cc: Russell King <linux@arm.linux.org.uk>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
We need a mechanism to let an inbound CPU signal that it is alive before
even getting into the kernel environment i.e. from early assembly code.
Using an IPI is the simplest way to achieve that.
This adds some basic infrastructure to register a struct completion
pointer to be "completed" when the dedicated IPI for this task is
received.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
This branch contains code cleanups, moves and removals for 3.12.
There's a large number of various cleanups, and a nice net removal of
13500 lines of code.
Highlights worth mentioning are:
- A series of patches from Stephen Boyd removing the ARM local timer API.
- Move of Qualcomm MSM IOMMU code to drivers/iommu.
- Samsung PWM driver cleanups from Tomasz Figa, removing legacy PWM driver
and switching over to the drivers/pwm one.
- Removal of some unusued auto-generated headers for OMAP2+ (PRM/CM).
There's also a move of a header file out of include/linux/i2c/ to
platform_data, where it really belongs. It touches mostly ARM platform
code for include changes so we took it through our tree.
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Merge tag 'cleanup-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
Pull ARM SoC cleanups from Olof Johansson:
"This branch contains code cleanups, moves and removals for 3.12.
There's a large number of various cleanups, and a nice net removal of
13500 lines of code.
Highlights worth mentioning are:
- A series of patches from Stephen Boyd removing the ARM local timer
API.
- Move of Qualcomm MSM IOMMU code to drivers/iommu.
- Samsung PWM driver cleanups from Tomasz Figa, removing legacy PWM
driver and switching over to the drivers/pwm one.
- Removal of some unusued auto-generated headers for OMAP2+ (PRM/CM).
There's also a move of a header file out of include/linux/i2c/ to
platform_data, where it really belongs. It touches mostly ARM
platform code for include changes so we took it through our tree"
* tag 'cleanup-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (83 commits)
ARM: OMAP2+: Add back the define for AM33XX_RST_GLOBAL_WARM_SW_MASK
gpio: (gpio-pca953x) move header to linux/platform_data/
arm: zynq: hotplug: Remove unreachable code
ARM: SAMSUNG: Remove unnecessary exynos4_default_sdhci*()
tegra: simplify use of devm_ioremap_resource
ARM: SAMSUNG: Remove plat/regs-timer.h header
ARM: SAMSUNG: Remove remaining uses of plat/regs-timer.h header
ARM: SAMSUNG: Remove pwm-clock infrastructure
ARM: SAMSUNG: Remove old PWM timer platform devices
pwm: Remove superseded pwm-samsung-legacy driver
ARM: SAMSUNG: Modify board files to use new PWM platform device
ARM: SAMSUNG: Rework private data handling in dev-backlight
pwm: Add new pwm-samsung driver
ARM: mach-mvebu: remove redundant DT parsing and validation
ARM: msm: Only compile io.c on platforms that use it
iommu/msm: Move mach includes to iommu directory
ARM: msm: Remove devices-iommu.c
ARM: msm: Move mach/board.h contents to common.h
ARM: msm: Migrate msm_timer to CLOCKSOURCE_OF_DECLARE
ARM: msm: Remove TMR and TMR0 static mappings
...
Now that we support a timer-backed delay loop, I'm quickly getting sick
and tired of people complaining that their beloved bogomips value has
decreased. You know who you are!
This patch removes the bogomips line from /proc/cpuinfo, based on the
reasoning that any program parsing this is already broken and, as such,
won't be further broken if the field is removed.
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Architectures should fully validate whether kexec is possible as part of
machine_kexec_prepare(), so that user-space's kexec_load() operation can
report any problems. Performing validation in machine_kexec() itself is
too late, since it is not allowed to return.
Prior to this patch, ARM's machine_kexec() was testing after-the-fact
whether machine_kexec_prepare() was able to disable all but one CPU.
Instead, modify machine_kexec_prepare() to validate all conditions
necessary for machine_kexec_prepare()'s to succeed. BUG if the validation
succeeded, yet disabling the CPUs didn't actually work.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
timer API entirely. Doing so will reduce code in ARM core, reduce the
architecture dependencies of our timer drivers, and simplify the code because
we no longer go through an architecture layer that is essentially a hotplug
notifier.
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Merge tag 'remove-local-timers' of git://git.kernel.org/pub/scm/linux/kernel/git/davidb/linux-msm into next/cleanup
From Stephen Boyd:
Now that we have a generic arch hook for broadcast we can remove the
local timer API entirely. Doing so will reduce code in ARM core, reduce
the architecture dependencies of our timer drivers, and simplify the code
because we no longer go through an architecture layer that is essentially
a hotplug notifier.
* tag 'remove-local-timers' of git://git.kernel.org/pub/scm/linux/kernel/git/davidb/linux-msm:
ARM: smp: Remove local timer API
clocksource: time-armada-370-xp: Divorce from local timer API
clocksource: time-armada-370-xp: Fix sparse warning
ARM: msm: Divorce msm_timer from local timer API
ARM: PRIMA2: Divorce timer-marco from local timer API
ARM: EXYNOS4: Divorce mct from local timer API
ARM: OMAP2+: Divorce from local timer API
ARM: smp_twd: Divorce smp_twd from local timer API
ARM: smp: Remove duplicate dummy timer implementation
Resolved a large number of conflicts due to __cpuinit cleanups, etc.
Signed-off-by: Olof Johansson <olof@lixom.net>
The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications. For example, the fix in
commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.
After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out. Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.
Note that some harmless section mismatch warnings may result, since
notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c)
and are flagged as __cpuinit -- so if we remove the __cpuinit from
the arch specific callers, we will also get section mismatch warnings.
As an intermediate step, we intend to turn the linux/init.h cpuinit
related content into no-ops as early as possible, since that will get
rid of these warnings. In any case, they are temporary and harmless.
This removes all the ARM uses of the __cpuinit macros from C code,
and all __CPUINIT from assembly code. It also had two ".previous"
section statements that were paired off against __CPUINIT
(aka .section ".cpuinit.text") that also get removed here.
[1] https://lkml.org/lkml/2013/5/20/589
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
There are no more users of this API, remove it.
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Drop ARM's version of the dummy timer now that we have a generic
implementation in drivers/clocksource.
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Conflicts:
arch/arm/kernel/smp.c
Please pull these miscellaneous LPAE fixes I've been collecting for a while
now for 3.11. They've been tested and reviewed by quite a few people, and most
of the patches are pretty trivial. -- Will Deacon.
Add comments to machine_shutdown()/halt()/power_off()/restart() that
describe their purpose and/or requirements re: CPUs being active/not.
In machine_shutdown(), replace the call to smp_send_stop() with a call to
disable_nonboot_cpus(). This completely disables all but one CPU, thus
satisfying the requirement that only a single CPU be active for kexec.
Adjust Kconfig dependencies for this change.
In machine_halt()/power_off()/restart(), call smp_send_stop() directly,
rather than via machine_shutdown(); these functions don't need to
completely de-activate all CPUs using hotplug, but rather just quiesce
them.
Remove smp_kill_cpus(), and its call from smp_send_stop().
smp_kill_cpus() was indirectly calling smp_ops.cpu_kill() without calling
smp_ops.cpu_die() on the target CPUs first. At least some implementations
of smp_ops had issues with this; it caused cpu_kill() to hang on Tegra,
for example. Since smp_send_stop() is only used for shutdown, halt, and
power-off, there is no need to attempt any kind of CPU hotplug here.
Adjust Kconfig to reflect that machine_shutdown() (and hence kexec)
relies upon disable_nonboot_cpus(). However, this alone doesn't guarantee
that hotplug will work, or even that hotplug is implemented for a
particular piece of HW that a multi-platform zImage runs on. Hence, add
error-checking to machine_kexec() to determine whether it did work.
Suggested-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Tested-by: Zhangfei Gao <zhangfei.gao@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Chris Metcalf