linux-stable.git/include/linux/cpuhotplug.h, branch v4.9.321

random: clear fast pool, crng, and batches in cpuhp bring up

2022-06-25T09:45:10+00:00

commit 3191dd5a1179ef0fad5a050a1702ae98b6251e8f upstream.

For the irq randomness fast pool, rather than having to use expensive
atomics, which were visibly the most expensive thing in the entire irq
handler, simply take care of the extreme edge case of resetting count to
zero in the cpuhp online handler, just after workqueues have been
reenabled. This simplifies the code a bit and lets us use vanilla
variables rather than atomics, and performance should be improved.

As well, very early on when the CPU comes up, while interrupts are still
disabled, we clear out the per-cpu crng and its batches, so that it
always starts with fresh randomness.

Cc: Thomas Gleixner 
Cc: Peter Zijlstra 
Cc: Theodore Ts'o 
Cc: Sultan Alsawaf 
Cc: Dominik Brodowski 
Acked-by: Sebastian Andrzej Siewior 
Signed-off-by: Jason A. Donenfeld 
Signed-off-by: Greg Kroah-Hartman

clocksource/drivers/exynos_mct: Increase priority over ARM arch timer

2019-08-04T07:33:22+00:00

[ Upstream commit 6282edb72bed5324352522d732080d4c1b9dfed6 ]

Exynos SoCs based on CA7/CA15 have 2 timer interfaces: custom Exynos MCT
(Multi Core Timer) and standard ARM Architected Timers.

There are use cases, where both timer interfaces are used simultanously.
One of such examples is using Exynos MCT for the main system timer and
ARM Architected Timers for the KVM and virtualized guests (KVM requires
arch timers).

Exynos Multi-Core Timer driver (exynos_mct) must be however started
before ARM Architected Timers (arch_timer), because they both share some
common hardware blocks (global system counter) and turning on MCT is
needed to get ARM Architected Timer working properly.

To ensure selecting Exynos MCT as the main system timer, increase MCT
timer rating. To ensure proper starting order of both timers during
suspend/resume cycle, increase MCT hotplug priority over ARM Archictected
Timers.

Signed-off-by: Marek Szyprowski 
Reviewed-by: Krzysztof Kozlowski 
Reviewed-by: Chanwoo Choi 
Signed-off-by: Daniel Lezcano 
Signed-off-by: Sasha Levin

timers: Reinitialize per cpu bases on hotplug

2018-01-02T19:35:17+00:00

commit 26456f87aca7157c057de65c9414b37f1ab881d1 upstream.

The timer wheel bases are not (re)initialized on CPU hotplug. That leaves
them with a potentially stale clk and next_expiry valuem, which can cause
trouble then the CPU is plugged.

Add a prepare callback which forwards the clock, sets next_expiry to far in
the future and reset the control flags to a known state.

Set base->must_forward_clk so the first timer which is queued will try to
forward the clock to current jiffies.

Fixes: 500462a9de65 ("timers: Switch to a non-cascading wheel")
Reported-by: Paul E. McKenney 
Signed-off-by: Thomas Gleixner 
Cc: Peter Zijlstra 
Cc: Frederic Weisbecker 
Cc: Sebastian Siewior 
Cc: Anna-Maria Gleixner 
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1712272152200.2431@nanos
Signed-off-by: Greg Kroah-Hartman

perf/x86/intel/rapl: Make package handling more robust

2017-08-30T08:21:50+00:00

commit dd86e373e09fb16b83e8adf5c48c421a4ca76468 upstream.

The package management code in RAPL relies on package mapping being
available before a CPU is started. This changed with:

  9d85eb9119f4 ("x86/smpboot: Make logical package management more robust")

because the ACPI/BIOS information turned out to be unreliable, but that
left RAPL in broken state. This was not noticed because on a regular boot
all CPUs are online before RAPL is initialized.

A possible fix would be to reintroduce the mess which allocates a package
data structure in CPU prepare and when it turns out to already exist in
starting throw it away later in the CPU online callback. But that's a
horrible hack and not required at all because RAPL becomes functional for
perf only in the CPU online callback. That's correct because user space is
not yet informed about the CPU being onlined, so nothing caan rely on RAPL
being available on that particular CPU.

Move the allocation to the CPU online callback and simplify the hotplug
handling. At this point the package mapping is established and correct.

This also adds a missing check for available package data in the
event_init() function.

Reported-by: Yasuaki Ishimatsu 
Signed-off-by: Thomas Gleixner 
Cc: Alexander Shishkin 
Cc: Arnaldo Carvalho de Melo 
Cc: Jiri Olsa 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Sebastian Siewior 
Cc: Stephane Eranian 
Cc: Vince Weaver 
Fixes: 9d85eb9119f4 ("x86/smpboot: Make logical package management more robust")
Link: http://lkml.kernel.org/r/20170131230141.212593966@linutronix.de
Signed-off-by: Ingo Molnar 
[ jwang: backport to 4.9 fix Null pointer deref during hotplug cpu.]
Signed-off-by: Jack Wang 
Signed-off-by: Greg Kroah-Hartman

clocksource/dummy_timer: Move hotplug callback after the real timers

2017-01-12T10:39:45+00:00

commit 9bf11ecce5a2758e5a097c2f3a13d08552d0d6f9 upstream.

When the dummy timer callback is invoked before the real timer callbacks,
then it tries to install that timer for the starting CPU. If the platform
does not have a broadcast timer installed the installation fails with a
kernel crash. The crash happens due to a unconditional deference of the non
available broadcast device. This needs to be fixed in the timer core code.

But even when this is fixed in the core code then installing the dummy
timer before the real timers is a pointless exercise.

Move it to the end of the callback list.

Fixes: 00c1d17aab51 ("clocksource/dummy_timer: Convert to hotplug state machine")
Reported-and-tested-by: Mason 
Signed-off-by: Thomas Gleixner 
Cc: Mark Rutland 
Cc: Anna-Maria Gleixner 
Cc: Richard Cochran 
Cc: Sebastian Andrzej Siewior 
Cc: Daniel Lezcano 
Cc: Peter Zijlstra ,
Cc: Sebastian Frias 
Cc: Thibaud Cornic 
Cc: Robin Murphy 
Link: http://lkml.kernel.org/r/1147ef90-7877-e4d2-bb2b-5c4fa8d3144b@free.fr
Signed-off-by: Greg Kroah-Hartman

clocksource: Add J-Core timer/clocksource driver

2016-10-20T18:10:17+00:00

At the hardware level, the J-Core PIT is integrated with the interrupt
controller, but it is represented as its own device and has an
independent programming interface. It provides a 12-bit countdown
timer, which is not presently used, and a periodic timer. The interval
length for the latter is programmable via a 32-bit throttle register
whose units are determined by a bus-period register. The periodic
timer is used to implement both periodic and oneshot clock event
modes; in oneshot mode the interrupt handler simply disables the timer
as soon as it fires.

Despite its device tree node representing an interrupt for the PIT,
the actual irq generated is programmable, not hard-wired. The driver
is responsible for programming the PIT to generate the hardware irq
number that the DT assigns to it.

On SMP configurations, J-Core provides cpu-local instances of the PIT;
no broadcast timer is needed. This driver supports the creation of the
necessary per-cpu clock_event_device instances.

A nanosecond-resolution clocksource is provided using the J-Core "RTC"
registers, which give a 64-bit seconds count and 32-bit nanoseconds
that wrap every second. The driver converts these to a full-range
32-bit nanoseconds count.

Signed-off-by: Rich Felker 
Cc: Mark Rutland 
Cc: devicetree@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: Daniel Lezcano 
Cc: Rob Herring 
Link: http://lkml.kernel.org/r/b591ff12cc5ebf63d1edc98da26046f95a233814.1476393790.git.dalias@libc.org
Signed-off-by: Thomas Gleixner

Merge tag 'for-linus-4.9-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

2016-10-06T18:19:10+00:00

Pull xen updates from David Vrabel:
 "xen features and fixes for 4.9:

   - switch to new CPU hotplug mechanism

   - support driver_override in pciback

   - require vector callback for HVM guests (the alternate mechanism via
     the platform device has been broken for ages)"

* tag 'for-linus-4.9-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/x86: Update topology map for PV VCPUs
  xen/x86: Initialize per_cpu(xen_vcpu, 0) a little earlier
  xen/pciback: support driver_override
  xen/pciback: avoid multiple entries in slot list
  xen/pciback: simplify pcistub device handling
  xen: Remove event channel notification through Xen PCI platform device
  xen/events: Convert to hotplug state machine
  xen/x86: Convert to hotplug state machine
  x86/xen: add missing \n at end of printk warning message
  xen/grant-table: Use kmalloc_array() in arch_gnttab_valloc()
  xen: Make VPMU init message look less scary
  xen: rename xen_pmu_init() in sys-hypervisor.c
  hotplug: Prevent alloc/free of irq descriptors during cpu up/down (again)
  xen/x86: Move irq allocation from Xen smp_op.cpu_up()

Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm

2016-10-06T14:59:37+00:00

Pull ARM updates from Russell King:

 - Correct ARMs dma-mapping to use the correct printk format strings.

 - Avoid defining OBJCOPYFLAGS globally which upsets lkdtm rodata
   testing.

 - Cleanups to ARMs asm/memory.h include.

 - L2 cache cleanups.

 - Allow flat nommu binaries to be executed on ARM MMU systems.

 - Kernel hardening - add more read-only after init annotations,
   including making some kernel vdso variables const.

 - Ensure AMBA primecell clocks are appropriately defaulted.

 - ARM breakpoint cleanup.

 - Various StrongARM 11x0 and companion chip (SA1111) updates to bring
   this legacy platform to use more modern APIs for (eg) GPIOs and
   interrupts, which will allow us in the future to reduce some of the
   board-level driver clutter and elimate function callbacks into board
   code via platform data. There still appears to be interest in these
   platforms!

 - Remove the now redundant secure_flush_area() API.

 - Module PLT relocation optimisations. Ard says: This series of 4
   patches optimizes the ARM PLT generation code that is invoked at
   module load time, to get rid of the O(n^2) algorithm that results in
   pathological load times of 10 seconds or more for large modules on
   certain STB platforms.

 - ARMv7M cache maintanence support.

 - L2 cache PMU support

* 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (35 commits)
  ARM: sa1111: provide to_sa1111_device() macro
  ARM: sa1111: add sa1111_get_irq()
  ARM: sa1111: clean up duplication in IRQ chip implementation
  ARM: sa1111: implement a gpio_chip for SA1111 GPIOs
  ARM: sa1111: move irq cleanup to separate function
  ARM: sa1111: use devm_clk_get()
  ARM: sa1111: use devm_kzalloc()
  ARM: sa1111: ensure we only touch RAB bus type devices when removing
  ARM: 8611/1: l2x0: add PMU support
  ARM: 8610/1: V7M: Add dsb before jumping in handler mode
  ARM: 8609/1: V7M: Add support for the Cortex-M7 processor
  ARM: 8608/1: V7M: Indirect proc_info construction for V7M CPUs
  ARM: 8607/1: V7M: Wire up caches for V7M processors with cache support.
  ARM: 8606/1: V7M: introduce cache operations
  ARM: 8605/1: V7M: fix notrace variant of save_and_disable_irqs
  ARM: 8604/1: V7M: Add support for reading the CTR with read_cpuid_cachetype()
  ARM: 8603/1: V7M: Add addresses for mem-mapped V7M cache operations
  ARM: 8602/1: factor out CSSELR/CCSIDR operations that use cp15 directly
  ARM: kernel: avoid brute force search on PLT generation
  ARM: kernel: sort relocation sections before allocating PLTs
  ...

Merge branches 'misc' and 'sa1111-base' into for-linus

2016-10-06T07:56:43+00:00

Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2016-10-04T02:43:08+00:00

Pull CPU hotplug updates from Thomas Gleixner:
 "Yet another batch of cpu hotplug core updates and conversions:

   - Provide core infrastructure for multi instance drivers so the
     drivers do not have to keep custom lists.

   - Convert custom lists to the new infrastructure. The block-mq custom
     list conversion comes through the block tree and makes the diffstat
     tip over to more lines removed than added.

   - Handle unbalanced hotplug enable/disable calls more gracefully.

   - Remove the obsolete CPU_STARTING/DYING notifier support.

   - Convert another batch of notifier users.

   The relayfs changes which conflicted with the conversion have been
   shipped to me by Andrew.

   The remaining lot is targeted for 4.10 so that we finally can remove
   the rest of the notifiers"

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (46 commits)
  cpufreq: Fix up conversion to hotplug state machine
  blk/mq: Reserve hotplug states for block multiqueue
  x86/apic/uv: Convert to hotplug state machine
  s390/mm/pfault: Convert to hotplug state machine
  mips/loongson/smp: Convert to hotplug state machine
  mips/octeon/smp: Convert to hotplug state machine
  fault-injection/cpu: Convert to hotplug state machine
  padata: Convert to hotplug state machine
  cpufreq: Convert to hotplug state machine
  ACPI/processor: Convert to hotplug state machine
  virtio scsi: Convert to hotplug state machine
  oprofile/timer: Convert to hotplug state machine
  block/softirq: Convert to hotplug state machine
  lib/irq_poll: Convert to hotplug state machine
  x86/microcode: Convert to hotplug state machine
  sh/SH-X3 SMP: Convert to hotplug state machine
  ia64/mca: Convert to hotplug state machine
  ARM/OMAP/wakeupgen: Convert to hotplug state machine
  ARM/shmobile: Convert to hotplug state machine
  arm64/FP/SIMD: Convert to hotplug state machine
  ...