<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/arch/arm64/kernel/cpuinfo.c, branch v5.3</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux</title>
<updated>2019-07-08T16:54:55+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2019-07-08T16:54:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=dfd437a257924484b144ee750e60affc95562c6d'/>
<id>dfd437a257924484b144ee750e60affc95562c6d</id>
<content type='text'>
Pull arm64 updates from Catalin Marinas:

 - arm64 support for syscall emulation via PTRACE_SYSEMU{,_SINGLESTEP}

 - Wire up VM_FLUSH_RESET_PERMS for arm64, allowing the core code to
   manage the permissions of executable vmalloc regions more strictly

 - Slight performance improvement by keeping softirqs enabled while
   touching the FPSIMD/SVE state (kernel_neon_begin/end)

 - Expose a couple of ARMv8.5 features to user (HWCAP): CondM (new
   XAFLAG and AXFLAG instructions for floating point comparison flags
   manipulation) and FRINT (rounding floating point numbers to integers)

 - Re-instate ARM64_PSEUDO_NMI support which was previously marked as
   BROKEN due to some bugs (now fixed)

 - Improve parking of stopped CPUs and implement an arm64-specific
   panic_smp_self_stop() to avoid warning on not being able to stop
   secondary CPUs during panic

 - perf: enable the ARM Statistical Profiling Extensions (SPE) on ACPI
   platforms

 - perf: DDR performance monitor support for iMX8QXP

 - cache_line_size() can now be set from DT or ACPI/PPTT if provided to
   cope with a system cache info not exposed via the CPUID registers

 - Avoid warning on hardware cache line size greater than
   ARCH_DMA_MINALIGN if the system is fully coherent

 - arm64 do_page_fault() and hugetlb cleanups

 - Refactor set_pte_at() to avoid redundant READ_ONCE(*ptep)

 - Ignore ACPI 5.1 FADTs reported as 5.0 (infer from the
   'arm_boot_flags' introduced in 5.1)

 - CONFIG_RANDOMIZE_BASE now enabled in defconfig

 - Allow the selection of ARM64_MODULE_PLTS, currently only done via
   RANDOMIZE_BASE (and an erratum workaround), allowing modules to spill
   over into the vmalloc area

 - Make ZONE_DMA32 configurable

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (54 commits)
  perf: arm_spe: Enable ACPI/Platform automatic module loading
  arm_pmu: acpi: spe: Add initial MADT/SPE probing
  ACPI/PPTT: Add function to return ACPI 6.3 Identical tokens
  ACPI/PPTT: Modify node flag detection to find last IDENTICAL
  x86/entry: Simplify _TIF_SYSCALL_EMU handling
  arm64: rename dump_instr as dump_kernel_instr
  arm64/mm: Drop [PTE|PMD]_TYPE_FAULT
  arm64: Implement panic_smp_self_stop()
  arm64: Improve parking of stopped CPUs
  arm64: Expose FRINT capabilities to userspace
  arm64: Expose ARMv8.5 CondM capability to userspace
  arm64: defconfig: enable CONFIG_RANDOMIZE_BASE
  arm64: ARM64_MODULES_PLTS must depend on MODULES
  arm64: bpf: do not allocate executable memory
  arm64/kprobes: set VM_FLUSH_RESET_PERMS on kprobe instruction pages
  arm64/mm: wire up CONFIG_ARCH_HAS_SET_DIRECT_MAP
  arm64: module: create module allocations without exec permissions
  arm64: Allow user selection of ARM64_MODULE_PLTS
  acpi/arm64: ignore 5.1 FADTs that are reported as 5.0
  arm64: Allow selecting Pseudo-NMI again
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull arm64 updates from Catalin Marinas:

 - arm64 support for syscall emulation via PTRACE_SYSEMU{,_SINGLESTEP}

 - Wire up VM_FLUSH_RESET_PERMS for arm64, allowing the core code to
   manage the permissions of executable vmalloc regions more strictly

 - Slight performance improvement by keeping softirqs enabled while
   touching the FPSIMD/SVE state (kernel_neon_begin/end)

 - Expose a couple of ARMv8.5 features to user (HWCAP): CondM (new
   XAFLAG and AXFLAG instructions for floating point comparison flags
   manipulation) and FRINT (rounding floating point numbers to integers)

 - Re-instate ARM64_PSEUDO_NMI support which was previously marked as
   BROKEN due to some bugs (now fixed)

 - Improve parking of stopped CPUs and implement an arm64-specific
   panic_smp_self_stop() to avoid warning on not being able to stop
   secondary CPUs during panic

 - perf: enable the ARM Statistical Profiling Extensions (SPE) on ACPI
   platforms

 - perf: DDR performance monitor support for iMX8QXP

 - cache_line_size() can now be set from DT or ACPI/PPTT if provided to
   cope with a system cache info not exposed via the CPUID registers

 - Avoid warning on hardware cache line size greater than
   ARCH_DMA_MINALIGN if the system is fully coherent

 - arm64 do_page_fault() and hugetlb cleanups

 - Refactor set_pte_at() to avoid redundant READ_ONCE(*ptep)

 - Ignore ACPI 5.1 FADTs reported as 5.0 (infer from the
   'arm_boot_flags' introduced in 5.1)

 - CONFIG_RANDOMIZE_BASE now enabled in defconfig

 - Allow the selection of ARM64_MODULE_PLTS, currently only done via
   RANDOMIZE_BASE (and an erratum workaround), allowing modules to spill
   over into the vmalloc area

 - Make ZONE_DMA32 configurable

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (54 commits)
  perf: arm_spe: Enable ACPI/Platform automatic module loading
  arm_pmu: acpi: spe: Add initial MADT/SPE probing
  ACPI/PPTT: Add function to return ACPI 6.3 Identical tokens
  ACPI/PPTT: Modify node flag detection to find last IDENTICAL
  x86/entry: Simplify _TIF_SYSCALL_EMU handling
  arm64: rename dump_instr as dump_kernel_instr
  arm64/mm: Drop [PTE|PMD]_TYPE_FAULT
  arm64: Implement panic_smp_self_stop()
  arm64: Improve parking of stopped CPUs
  arm64: Expose FRINT capabilities to userspace
  arm64: Expose ARMv8.5 CondM capability to userspace
  arm64: defconfig: enable CONFIG_RANDOMIZE_BASE
  arm64: ARM64_MODULES_PLTS must depend on MODULES
  arm64: bpf: do not allocate executable memory
  arm64/kprobes: set VM_FLUSH_RESET_PERMS on kprobe instruction pages
  arm64/mm: wire up CONFIG_ARCH_HAS_SET_DIRECT_MAP
  arm64: module: create module allocations without exec permissions
  arm64: Allow user selection of ARM64_MODULE_PLTS
  acpi/arm64: ignore 5.1 FADTs that are reported as 5.0
  arm64: Allow selecting Pseudo-NMI again
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: Expose FRINT capabilities to userspace</title>
<updated>2019-06-25T13:24:00+00:00</updated>
<author>
<name>Mark Brown</name>
<email>broonie@kernel.org</email>
</author>
<published>2019-06-18T18:10:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ca9503fc9e9812aa6258e55d44edb03eb30fc46f'/>
<id>ca9503fc9e9812aa6258e55d44edb03eb30fc46f</id>
<content type='text'>
ARMv8.5 introduces the FRINT series of instructions for rounding floating
point numbers to integers. Provide a capability to userspace in order to
allow applications to determine if the system supports these instructions.

Signed-off-by: Mark Brown &lt;broonie@kernel.org&gt;
Acked-by: Will Deacon &lt;will.deacon@arm.com&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
ARMv8.5 introduces the FRINT series of instructions for rounding floating
point numbers to integers. Provide a capability to userspace in order to
allow applications to determine if the system supports these instructions.

Signed-off-by: Mark Brown &lt;broonie@kernel.org&gt;
Acked-by: Will Deacon &lt;will.deacon@arm.com&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: Expose ARMv8.5 CondM capability to userspace</title>
<updated>2019-06-25T13:21:41+00:00</updated>
<author>
<name>Mark Brown</name>
<email>broonie@kernel.org</email>
</author>
<published>2019-06-18T18:10:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1201937491822b61641c1878ebcd16a93aed4540'/>
<id>1201937491822b61641c1878ebcd16a93aed4540</id>
<content type='text'>
ARMv8.5 adds new instructions XAFLAG and AXFLAG to translate the
representation of the results of floating point comparisons between the
native ARM format and an alternative format used by some software. Add
a hwcap allowing userspace to determine if they are present, since we
referred to earlier CondM extensions as FLAGM call these extensions
FLAGM2.

Signed-off-by: Mark Brown &lt;broonie@kernel.org&gt;
Acked-by: Will Deacon &lt;will.deacon@arm.com&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
ARMv8.5 adds new instructions XAFLAG and AXFLAG to translate the
representation of the results of floating point comparisons between the
native ARM format and an alternative format used by some software. Add
a hwcap allowing userspace to determine if they are present, since we
referred to earlier CondM extensions as FLAGM call these extensions
FLAGM2.

Signed-off-by: Mark Brown &lt;broonie@kernel.org&gt;
Acked-by: Will Deacon &lt;will.deacon@arm.com&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234</title>
<updated>2019-06-19T15:09:07+00:00</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2019-06-03T05:44:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=caab277b1de0a22b675c4c95fc7b285ec2eb5bf5'/>
<id>caab277b1de0a22b675c4c95fc7b285ec2eb5bf5</id>
<content type='text'>
Based on 1 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
  distributed in the hope that it will be useful but without any
  warranty without even the implied warranty of merchantability or
  fitness for a particular purpose see the gnu general public license
  for more details you should have received a copy of the gnu general
  public license along with this program if not see http www gnu org
  licenses

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 503 file(s).

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Alexios Zavras &lt;alexios.zavras@intel.com&gt;
Reviewed-by: Allison Randal &lt;allison@lohutok.net&gt;
Reviewed-by: Enrico Weigelt &lt;info@metux.net&gt;
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Based on 1 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
  distributed in the hope that it will be useful but without any
  warranty without even the implied warranty of merchantability or
  fitness for a particular purpose see the gnu general public license
  for more details you should have received a copy of the gnu general
  public license along with this program if not see http www gnu org
  licenses

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 503 file(s).

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Alexios Zavras &lt;alexios.zavras@intel.com&gt;
Reviewed-by: Allison Randal &lt;allison@lohutok.net&gt;
Reviewed-by: Enrico Weigelt &lt;info@metux.net&gt;
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: Expose SVE2 features for userspace</title>
<updated>2019-04-23T17:02:00+00:00</updated>
<author>
<name>Dave Martin</name>
<email>Dave.Martin@arm.com</email>
</author>
<published>2019-04-18T17:41:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=06a916feca2b262ab0c1a2aeb68882f4b1108a07'/>
<id>06a916feca2b262ab0c1a2aeb68882f4b1108a07</id>
<content type='text'>
This patch provides support for reporting the presence of SVE2 and
its optional features to userspace.

This will also enable visibility of SVE2 for guests, when KVM
support for SVE-enabled guests is available.

Signed-off-by: Dave Martin &lt;Dave.Martin@arm.com&gt;
Signed-off-by: Will Deacon &lt;will.deacon@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This patch provides support for reporting the presence of SVE2 and
its optional features to userspace.

This will also enable visibility of SVE2 for guests, when KVM
support for SVE-enabled guests is available.

Signed-off-by: Dave Martin &lt;Dave.Martin@arm.com&gt;
Signed-off-by: Will Deacon &lt;will.deacon@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: Expose DC CVADP to userspace</title>
<updated>2019-04-16T15:27:56+00:00</updated>
<author>
<name>Andrew Murray</name>
<email>andrew.murray@arm.com</email>
</author>
<published>2019-04-09T09:52:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=671db581815faf17cbedd7fcbc48823a247d90b1'/>
<id>671db581815faf17cbedd7fcbc48823a247d90b1</id>
<content type='text'>
ARMv8.5 builds upon the ARMv8.2 DC CVAP instruction by introducing a DC
CVADP instruction which cleans the data cache to the point of deep
persistence. Let's expose this support via the arm64 ELF hwcaps.

Signed-off-by: Andrew Murray &lt;andrew.murray@arm.com&gt;
Reviewed-by: Dave Martin &lt;Dave.Martin@arm.com&gt;
Signed-off-by: Will Deacon &lt;will.deacon@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
ARMv8.5 builds upon the ARMv8.2 DC CVAP instruction by introducing a DC
CVADP instruction which cleans the data cache to the point of deep
persistence. Let's expose this support via the arm64 ELF hwcaps.

Signed-off-by: Andrew Murray &lt;andrew.murray@arm.com&gt;
Reviewed-by: Dave Martin &lt;Dave.Martin@arm.com&gt;
Signed-off-by: Will Deacon &lt;will.deacon@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: HWCAP: add support for AT_HWCAP2</title>
<updated>2019-04-16T15:27:12+00:00</updated>
<author>
<name>Andrew Murray</name>
<email>andrew.murray@arm.com</email>
</author>
<published>2019-04-09T09:52:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=aaba098fe6ce594ae6f963dc041be6307e499f19'/>
<id>aaba098fe6ce594ae6f963dc041be6307e499f19</id>
<content type='text'>
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 &lt;andrew.murray@arm.com&gt;
[will: use const_ilog2() and tweak documentation]
Signed-off-by: Will Deacon &lt;will.deacon@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
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 &lt;andrew.murray@arm.com&gt;
[will: use const_ilog2() and tweak documentation]
Signed-off-by: Will Deacon &lt;will.deacon@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: add basic pointer authentication support</title>
<updated>2018-12-13T16:42:46+00:00</updated>
<author>
<name>Mark Rutland</name>
<email>mark.rutland@arm.com</email>
</author>
<published>2018-12-07T18:39:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7503197562567b57ec14feb3a9d5400ebc56812f'/>
<id>7503197562567b57ec14feb3a9d5400ebc56812f</id>
<content type='text'>
This patch adds basic support for pointer authentication, allowing
userspace to make use of APIAKey, APIBKey, APDAKey, APDBKey, and
APGAKey. The kernel maintains key values for each process (shared by all
threads within), which are initialised to random values at exec() time.

The ID_AA64ISAR1_EL1.{APA,API,GPA,GPI} fields are exposed to userspace,
to describe that pointer authentication instructions are available and
that the kernel is managing the keys. Two new hwcaps are added for the
same reason: PACA (for address authentication) and PACG (for generic
authentication).

Reviewed-by: Richard Henderson &lt;richard.henderson@linaro.org&gt;
Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Signed-off-by: Kristina Martsenko &lt;kristina.martsenko@arm.com&gt;
Tested-by: Adam Wallis &lt;awallis@codeaurora.org&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Ramana Radhakrishnan &lt;ramana.radhakrishnan@arm.com&gt;
Cc: Suzuki K Poulose &lt;suzuki.poulose@arm.com&gt;
Cc: Will Deacon &lt;will.deacon@arm.com&gt;
[will: Fix sizeof() usage and unroll address key initialisation]
Signed-off-by: Will Deacon &lt;will.deacon@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This patch adds basic support for pointer authentication, allowing
userspace to make use of APIAKey, APIBKey, APDAKey, APDBKey, and
APGAKey. The kernel maintains key values for each process (shared by all
threads within), which are initialised to random values at exec() time.

The ID_AA64ISAR1_EL1.{APA,API,GPA,GPI} fields are exposed to userspace,
to describe that pointer authentication instructions are available and
that the kernel is managing the keys. Two new hwcaps are added for the
same reason: PACA (for address authentication) and PACG (for generic
authentication).

Reviewed-by: Richard Henderson &lt;richard.henderson@linaro.org&gt;
Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Signed-off-by: Kristina Martsenko &lt;kristina.martsenko@arm.com&gt;
Tested-by: Adam Wallis &lt;awallis@codeaurora.org&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Ramana Radhakrishnan &lt;ramana.radhakrishnan@arm.com&gt;
Cc: Suzuki K Poulose &lt;suzuki.poulose@arm.com&gt;
Cc: Will Deacon &lt;will.deacon@arm.com&gt;
[will: Fix sizeof() usage and unroll address key initialisation]
Signed-off-by: Will Deacon &lt;will.deacon@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: Add support for SB barrier and patch in over DSB; ISB sequences</title>
<updated>2018-12-06T16:47:04+00:00</updated>
<author>
<name>Will Deacon</name>
<email>will.deacon@arm.com</email>
</author>
<published>2018-06-14T10:21:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=bd4fb6d270bc423a9a4098108784f7f9254c4e6d'/>
<id>bd4fb6d270bc423a9a4098108784f7f9254c4e6d</id>
<content type='text'>
We currently use a DSB; ISB sequence to inhibit speculation in set_fs().
Whilst this works for current CPUs, future CPUs may implement a new SB
barrier instruction which acts as an architected speculation barrier.

On CPUs that support it, patch in an SB; NOP sequence over the DSB; ISB
sequence and advertise the presence of the new instruction to userspace.

Signed-off-by: Will Deacon &lt;will.deacon@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
We currently use a DSB; ISB sequence to inhibit speculation in set_fs().
Whilst this works for current CPUs, future CPUs may implement a new SB
barrier instruction which acts as an architected speculation barrier.

On CPUs that support it, patch in an SB; NOP sequence over the DSB; ISB
sequence and advertise the presence of the new instruction to userspace.

Signed-off-by: Will Deacon &lt;will.deacon@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: cpufeature: Fix handling of CTR_EL0.IDC field</title>
<updated>2018-10-16T10:53:31+00:00</updated>
<author>
<name>Suzuki K Poulose</name>
<email>suzuki.poulose@arm.com</email>
</author>
<published>2018-10-09T13:47:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1602df02f33f61fe0de1bbfeba0d1c97c14bff19'/>
<id>1602df02f33f61fe0de1bbfeba0d1c97c14bff19</id>
<content type='text'>
CTR_EL0.IDC reports the data cache clean requirements for instruction
to data coherence. However, if the field is 0, we need to check the
CLIDR_EL1 fields to detect the status of the feature. Currently we
don't do this and generate a warning with tainting the kernel, when
there is a mismatch in the field among the CPUs. Also the userspace
doesn't have a reliable way to check the CLIDR_EL1 register to check
the status.

This patch fixes the problem by checking the CLIDR_EL1 fields, when
(CTR_EL0.IDC == 0) and updates the kernel's copy of the CTR_EL0 for
the CPU with the actual status of the feature. This would allow the
sanity check infrastructure to do the proper checking of the fields
and also allow the CTR_EL0 emulation code to supply the real status
of the feature.

Now, if a CPU has raw CTR_EL0.IDC == 0 and effective IDC == 1 (with
overall system wide IDC == 1), we need to expose the real value to
the user. So, we trap CTR_EL0 access on the CPU which reports incorrect
CTR_EL0.IDC.

Fixes: commit 6ae4b6e057888 ("arm64: Add support for new control bits CTR_EL0.DIC and CTR_EL0.IDC")
Cc: Shanker Donthineni &lt;shankerd@codeaurora.org&gt;
Cc: Philip Elcan &lt;pelcan@codeaurora.org&gt;
Cc: Will Deacon &lt;will.deacon@arm.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Signed-off-by: Suzuki K Poulose &lt;suzuki.poulose@arm.com&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
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<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
CTR_EL0.IDC reports the data cache clean requirements for instruction
to data coherence. However, if the field is 0, we need to check the
CLIDR_EL1 fields to detect the status of the feature. Currently we
don't do this and generate a warning with tainting the kernel, when
there is a mismatch in the field among the CPUs. Also the userspace
doesn't have a reliable way to check the CLIDR_EL1 register to check
the status.

This patch fixes the problem by checking the CLIDR_EL1 fields, when
(CTR_EL0.IDC == 0) and updates the kernel's copy of the CTR_EL0 for
the CPU with the actual status of the feature. This would allow the
sanity check infrastructure to do the proper checking of the fields
and also allow the CTR_EL0 emulation code to supply the real status
of the feature.

Now, if a CPU has raw CTR_EL0.IDC == 0 and effective IDC == 1 (with
overall system wide IDC == 1), we need to expose the real value to
the user. So, we trap CTR_EL0 access on the CPU which reports incorrect
CTR_EL0.IDC.

Fixes: commit 6ae4b6e057888 ("arm64: Add support for new control bits CTR_EL0.DIC and CTR_EL0.IDC")
Cc: Shanker Donthineni &lt;shankerd@codeaurora.org&gt;
Cc: Philip Elcan &lt;pelcan@codeaurora.org&gt;
Cc: Will Deacon &lt;will.deacon@arm.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Signed-off-by: Suzuki K Poulose &lt;suzuki.poulose@arm.com&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</pre>
</div>
</content>
</entry>
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