linux-stable.git/drivers/clocksource/arm_arch_timer.c, branch v5.4.78

arm64: arch_timer: Disable the compat vdso for cores affected by ARM64_WORKAROUND_1418040

2020-07-22T07:32:51+00:00

commit 4b661d6133c5d3a7c9aca0b4ee5a78c7766eff3f upstream.

ARM64_WORKAROUND_1418040 requires that AArch32 EL0 accesses to
the virtual counter register are trapped and emulated by the kernel.
This makes the vdso pretty pointless, and in some cases livelock
prone.

Provide a workaround entry that limits the vdso to 64bit tasks.

Signed-off-by: Marc Zyngier 
Acked-by: Mark Rutland 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200706163802.1836732-4-maz@kernel.org
Signed-off-by: Will Deacon 
Signed-off-by: Marc Zyngier 
Signed-off-by: Greg Kroah-Hartman

arm64: arch_timer: Allow an workaround descriptor to disable compat vdso

2020-07-22T07:32:50+00:00

commit c1fbec4ac0d701f350a581941d35643d5a9cd184 upstream.

As we are about to disable the vdso for compat tasks in some circumstances,
let's allow a workaround descriptor to express exactly that.

Signed-off-by: Marc Zyngier 
Acked-by: Mark Rutland 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200706163802.1836732-3-maz@kernel.org
Signed-off-by: Will Deacon 
Signed-off-by: Marc Zyngier 
Signed-off-by: Greg Kroah-Hartman

arm64: Introduce a way to disable the 32bit vdso

2020-07-22T07:32:50+00:00

commit 97884ca8c2925d14c32188e865069f21378b4b4f upstream.

[this is a redesign rather than a backport]

We have a class of errata (grouped under the ARM64_WORKAROUND_1418040
banner) that force the trapping of counter access from 32bit EL0.

We would normally disable the whole vdso for such defect, except that
it would disable it for 64bit userspace as well, which is a shame.

Instead, add a new vdso_clock_mode, which signals that the vdso
isn't usable for compat tasks.  This gets checked in the new
vdso_clocksource_ok() helper, now provided for the 32bit vdso.

Signed-off-by: Marc Zyngier 
Acked-by: Mark Rutland 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200706163802.1836732-2-maz@kernel.org
Signed-off-by: Will Deacon 
Signed-off-by: Marc Zyngier 
Signed-off-by: Greg Kroah-Hartman

Merge branch 'timers/vdso' into timers/core

2019-07-03T08:50:21+00:00

so the hyper-v clocksource update can be applied.

clocksource/drivers/arm_arch_timer: Extract elf_hwcap use to arch-helper

2019-06-25T17:49:18+00:00

Different mechanisms are used to test and set elf_hwcaps between ARM
and ARM64, this results in the use of ifdeferry in this file when
setting/testing for the EVTSTRM hwcap.

Let's improve readability by extracting this to an arch helper.

Signed-off-by: Andrew Murray 
Acked-by: Mark Rutland 
Acked-by: Will Deacon 
Signed-off-by: Daniel Lezcano

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