linux-stable.git/drivers/clocksource/arm_arch_timer.c, branch v5.2.3

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

2019-06-19T15:09:55+00:00

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 foundation

  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 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

clocksource/drivers/arm_arch_timer: Don't trace count reader functions

2019-06-12T13:38:54+00:00

With v5.2-rc1, The ftrace functions_graph tracer locks up whenever it is
enabled on arm64.

Since commit 0ea415390cd3 ("clocksource/arm_arch_timer: Use
arch_timer_read_counter to access stable counters") a function pointer
is consistently used to read the counter instead of potentially
referencing an inlinable function.

The graph tracers relies on accessing the timer counters to compute the
time spent in functions which causes the lockup when attempting to trace
these code paths.

Annotate the arm arch timer counter accessors as notrace.

Fixes: 0ea415390cd3 ("clocksource/arm_arch_timer: Use
       arch_timer_read_counter to access stable counters")
Signed-off-by: Julien Thierry 
Cc: Marc Zyngier 
Cc: Mark Rutland 
Cc: Daniel Lezcano 
Cc: Thomas Gleixner 
Cc: Steven Rostedt 
Acked-by: Marc Zyngier 
Signed-off-by: Daniel Lezcano

Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

2019-05-07T00:54:22+00:00

Pull arm64 updates from Will Deacon:
 "Mostly just incremental improvements here:

   - Introduce AT_HWCAP2 for advertising CPU features to userspace

   - Expose SVE2 availability to userspace

   - Support for "data cache clean to point of deep persistence" (DC PODP)

   - Honour "mitigations=off" on the cmdline and advertise status via
     sysfs

   - CPU timer erratum workaround (Neoverse-N1 #1188873)

   - Introduce perf PMU driver for the SMMUv3 performance counters

   - Add config option to disable the kuser helpers page for AArch32 tasks

   - Futex modifications to ensure liveness under contention

   - Rework debug exception handling to seperate kernel and user
     handlers

   - Non-critical fixes and cleanup"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (92 commits)
  Documentation: Add ARM64 to kernel-parameters.rst
  arm64/speculation: Support 'mitigations=' cmdline option
  arm64: ssbs: Don't treat CPUs with SSBS as unaffected by SSB
  arm64: enable generic CPU vulnerabilites support
  arm64: add sysfs vulnerability show for speculative store bypass
  arm64: Fix size of __early_cpu_boot_status
  clocksource/arm_arch_timer: Use arch_timer_read_counter to access stable counters
  clocksource/arm_arch_timer: Remove use of workaround static key
  clocksource/arm_arch_timer: Drop use of static key in arch_timer_reg_read_stable
  clocksource/arm_arch_timer: Direcly assign set_next_event workaround
  arm64: Use arch_timer_read_counter instead of arch_counter_get_cntvct
  watchdog/sbsa: Use arch_timer_read_counter instead of arch_counter_get_cntvct
  ARM: vdso: Remove dependency with the arch_timer driver internals
  arm64: Apply ARM64_ERRATUM_1188873 to Neoverse-N1
  arm64: Add part number for Neoverse N1
  arm64: Make ARM64_ERRATUM_1188873 depend on COMPAT
  arm64: Restrict ARM64_ERRATUM_1188873 mitigation to AArch32
  arm64: mm: Remove pte_unmap_nested()
  arm64: Fix compiler warning from pte_unmap() with -Wunused-but-set-variable
  arm64: compat: Reduce address limit for 64K pages
  ...

Merge branch 'for-next/timers' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux into for-next/core

2019-05-01T14:45:36+00:00

Conflicts:
	arch/arm64/Kconfig
	arch/arm64/include/asm/arch_timer.h

clocksource/arm_arch_timer: Use arch_timer_read_counter to access stable counters

2019-04-30T15:12:54+00:00

Instead of always going via arch_counter_get_cntvct_stable to access the
counter workaround, let's have arch_timer_read_counter point to the
right method.

For that, we need to track whether any CPU in the system has a
workaround for the counter. This is done by having an atomic variable
tracking this.

Acked-by: Mark Rutland 
Signed-off-by: Marc Zyngier 
Signed-off-by: Will Deacon

clocksource/arm_arch_timer: Remove use of workaround static key

2019-04-30T15:11:47+00:00

The use of a static key in a hotplug path has proved to be a real
nightmare, and makes it impossible to have scream-free lockdep
kernel.

Let's remove the static key altogether, and focus on something saner.

Acked-by: Mark Rutland 
Acked-by: Daniel Lezcano 
Signed-off-by: Marc Zyngier 
Signed-off-by: Will Deacon

clocksource/arm_arch_timer: Direcly assign set_next_event workaround

2019-04-30T15:10:57+00:00

When a given timer is affected by an erratum and requires an
alternative implementation of set_next_event, we do a rather
complicated dance to detect and call the workaround on each
set_next_event call.

This is clearly idiotic, as we can perfectly detect whether
this CPU requires a workaround while setting up the clock event
device.

This only requires the CPU-specific detection to be done a bit
earlier, and we can then safely override the set_next_event pointer
if we have a workaround associated to that CPU.

Acked-by: Mark Rutland 
Acked-by; Daniel Lezcano 
Signed-off-by: Marc Zyngier 
Signed-off-by: Will Deacon

arm64: Restrict ARM64_ERRATUM_1188873 mitigation to AArch32

2019-04-30T13:45:53+00:00

We currently deal with ARM64_ERRATUM_1188873 by always trapping EL0
accesses for both instruction sets. Although nothing wrong comes out
of that, people trying to squeeze the last drop of performance from
buggy HW find this over the top. Oh well.

Let's change the mitigation by flipping the counter enable bit
on return to userspace. Non-broken HW gets an extra branch on
the fast path, which is hopefully not the end of the world.
The arch timer workaround is also removed.

Acked-by: Daniel Lezcano 
Signed-off-by: Marc Zyngier 
Signed-off-by: Will Deacon

arm64: HWCAP: add support for AT_HWCAP2

2019-04-16T15:27:12+00:00

As we will exhaust the first 32 bits of AT_HWCAP let's start
exposing AT_HWCAP2 to userspace to give us up to 64 caps.

Whilst it's possible to use the remaining 32 bits of AT_HWCAP, we
prefer to expand into AT_HWCAP2 in order to provide a consistent
view to userspace between ILP32 and LP64. However internal to the
kernel we prefer to continue to use the full space of elf_hwcap.

To reduce complexity and allow for future expansion, we now
represent hwcaps in the kernel as ordinals and use a
KERNEL_HWCAP_ prefix. This allows us to support automatic feature
based module loading for all our hwcaps.

We introduce cpu_set_feature to set hwcaps which complements the
existing cpu_have_feature helper. These helpers allow us to clean
up existing direct uses of elf_hwcap and reduce any future effort
required to move beyond 64 caps.

For convenience we also introduce cpu_{have,set}_named_feature which
makes use of the cpu_feature macro to allow providing a hwcap name
without a {KERNEL_}HWCAP_ prefix.

Signed-off-by: Andrew Murray 
[will: use const_ilog2() and tweak documentation]
Signed-off-by: Will Deacon

clocksource/drivers/arm_arch_timer: Remove unneeded pr_fmt macro

2019-04-11T20:13:43+00:00

After this commit ded24019b6b6f(clocksource: arm_arch_timer: clean up
printk usage), the previous macro is redundant, so delete it.

And move the new macro to the previous position.

Signed-off-by: Yangtao Li 
Signed-off-by: Daniel Lezcano