<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/Documentation, branch v5.4.282</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>arm64: cpufeature: Fix the visibility of compat hwcaps</title>
<updated>2024-08-19T03:33:54+00:00</updated>
<author>
<name>Amit Daniel Kachhap</name>
<email>amit.kachhap@arm.com</email>
</author>
<published>2022-11-03T08:22:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f6a745c5580821569cef454cab52a2b7acaccd2a'/>
<id>f6a745c5580821569cef454cab52a2b7acaccd2a</id>
<content type='text'>
commit 85f1506337f0c79a4955edfeee86a18628e3735f upstream.

Commit 237405ebef58 ("arm64: cpufeature: Force HWCAP to be based on the
sysreg visible to user-space") forced the hwcaps to use sanitised
user-space view of the id registers. However, the ID register structures
used to select few compat cpufeatures (vfp, crc32, ...) are masked and
hence such hwcaps do not appear in /proc/cpuinfo anymore for PER_LINUX32
personality.

Add the ID register structures explicitly and set the relevant entry as
visible. As these ID registers are now of type visible so make them
available in 64-bit userspace by making necessary changes in register
emulation logic and documentation.

While at it, update the comment for structure ftr_generic_32bits[] which
lists the ID register that use it.

Fixes: 237405ebef58 ("arm64: cpufeature: Force HWCAP to be based on the sysreg visible to user-space")
Cc: Suzuki K Poulose &lt;suzuki.poulose@arm.com&gt;
Reviewed-by: James Morse &lt;james.morse@arm.com&gt;
Signed-off-by: Amit Daniel Kachhap &lt;amit.kachhap@arm.com&gt;
Link: https://lore.kernel.org/r/20221103082232.19189-1-amit.kachhap@arm.com
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 85f1506337f0c79a4955edfeee86a18628e3735f upstream.

Commit 237405ebef58 ("arm64: cpufeature: Force HWCAP to be based on the
sysreg visible to user-space") forced the hwcaps to use sanitised
user-space view of the id registers. However, the ID register structures
used to select few compat cpufeatures (vfp, crc32, ...) are masked and
hence such hwcaps do not appear in /proc/cpuinfo anymore for PER_LINUX32
personality.

Add the ID register structures explicitly and set the relevant entry as
visible. As these ID registers are now of type visible so make them
available in 64-bit userspace by making necessary changes in register
emulation logic and documentation.

While at it, update the comment for structure ftr_generic_32bits[] which
lists the ID register that use it.

Fixes: 237405ebef58 ("arm64: cpufeature: Force HWCAP to be based on the sysreg visible to user-space")
Cc: Suzuki K Poulose &lt;suzuki.poulose@arm.com&gt;
Reviewed-by: James Morse &lt;james.morse@arm.com&gt;
Signed-off-by: Amit Daniel Kachhap &lt;amit.kachhap@arm.com&gt;
Link: https://lore.kernel.org/r/20221103082232.19189-1-amit.kachhap@arm.com
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: errata: Expand speculative SSBS workaround (again)</title>
<updated>2024-08-19T03:33:50+00:00</updated>
<author>
<name>Mark Rutland</name>
<email>mark.rutland@arm.com</email>
</author>
<published>2024-08-09T10:34:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ba9a332d1ef5bcf4677de1613ba449304e8f338d'/>
<id>ba9a332d1ef5bcf4677de1613ba449304e8f338d</id>
<content type='text'>
[ Upstream commit adeec61a4723fd3e39da68db4cc4d924e6d7f641 ]

A number of Arm Ltd CPUs suffer from errata whereby an MSR to the SSBS
special-purpose register does not affect subsequent speculative
instructions, permitting speculative store bypassing for a window of
time.

We worked around this for a number of CPUs in commits:

* 7187bb7d0b5c7dfa ("arm64: errata: Add workaround for Arm errata 3194386 and 3312417")
* 75b3c43eab594bfb ("arm64: errata: Expand speculative SSBS workaround")

Since then, similar errata have been published for a number of other Arm
Ltd CPUs, for which the same mitigation is sufficient. This is described
in their respective Software Developer Errata Notice (SDEN) documents:

* Cortex-A76 (MP052) SDEN v31.0, erratum 3324349
  https://developer.arm.com/documentation/SDEN-885749/3100/

* Cortex-A77 (MP074) SDEN v19.0, erratum 3324348
  https://developer.arm.com/documentation/SDEN-1152370/1900/

* Cortex-A78 (MP102) SDEN v21.0, erratum 3324344
  https://developer.arm.com/documentation/SDEN-1401784/2100/

* Cortex-A78C (MP138) SDEN v16.0, erratum 3324346
  https://developer.arm.com/documentation/SDEN-1707916/1600/

* Cortex-A78C (MP154) SDEN v10.0, erratum 3324347
  https://developer.arm.com/documentation/SDEN-2004089/1000/

* Cortex-A725 (MP190) SDEN v5.0, erratum 3456106
  https://developer.arm.com/documentation/SDEN-2832921/0500/

* Cortex-X1 (MP077) SDEN v21.0, erratum 3324344
  https://developer.arm.com/documentation/SDEN-1401782/2100/

* Cortex-X1C (MP136) SDEN v16.0, erratum 3324346
  https://developer.arm.com/documentation/SDEN-1707914/1600/

* Neoverse-N1 (MP050) SDEN v32.0, erratum 3324349
  https://developer.arm.com/documentation/SDEN-885747/3200/

* Neoverse-V1 (MP076) SDEN v19.0, erratum 3324341
  https://developer.arm.com/documentation/SDEN-1401781/1900/

Note that due to the manner in which Arm develops IP and tracks errata,
some CPUs share a common erratum number and some CPUs have multiple
erratum numbers for the same HW issue.

On parts without SB, it is necessary to use ISB for the workaround. The
spec_bar() macro used in the mitigation will expand to a "DSB SY; ISB"
sequence in this case, which is sufficient on all affected parts.

Enable the existing mitigation by adding the relevant MIDRs to
erratum_spec_ssbs_list. The list is sorted alphanumerically (involving
moving Neoverse-V3 after Neoverse-V2) so that this is easy to audit and
potentially extend again in future. The Kconfig text is also updated to
clarify the set of affected parts and the mitigation.

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: James Morse &lt;james.morse@arm.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Reviewed-by: Anshuman Khandual &lt;anshuman.khandual@arm.com&gt;
Acked-by: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/r/20240801101803.1982459-4-mark.rutland@arm.com
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
[ Mark: fix conflicts in silicon-errata.rst ]
Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit adeec61a4723fd3e39da68db4cc4d924e6d7f641 ]

A number of Arm Ltd CPUs suffer from errata whereby an MSR to the SSBS
special-purpose register does not affect subsequent speculative
instructions, permitting speculative store bypassing for a window of
time.

We worked around this for a number of CPUs in commits:

* 7187bb7d0b5c7dfa ("arm64: errata: Add workaround for Arm errata 3194386 and 3312417")
* 75b3c43eab594bfb ("arm64: errata: Expand speculative SSBS workaround")

Since then, similar errata have been published for a number of other Arm
Ltd CPUs, for which the same mitigation is sufficient. This is described
in their respective Software Developer Errata Notice (SDEN) documents:

* Cortex-A76 (MP052) SDEN v31.0, erratum 3324349
  https://developer.arm.com/documentation/SDEN-885749/3100/

* Cortex-A77 (MP074) SDEN v19.0, erratum 3324348
  https://developer.arm.com/documentation/SDEN-1152370/1900/

* Cortex-A78 (MP102) SDEN v21.0, erratum 3324344
  https://developer.arm.com/documentation/SDEN-1401784/2100/

* Cortex-A78C (MP138) SDEN v16.0, erratum 3324346
  https://developer.arm.com/documentation/SDEN-1707916/1600/

* Cortex-A78C (MP154) SDEN v10.0, erratum 3324347
  https://developer.arm.com/documentation/SDEN-2004089/1000/

* Cortex-A725 (MP190) SDEN v5.0, erratum 3456106
  https://developer.arm.com/documentation/SDEN-2832921/0500/

* Cortex-X1 (MP077) SDEN v21.0, erratum 3324344
  https://developer.arm.com/documentation/SDEN-1401782/2100/

* Cortex-X1C (MP136) SDEN v16.0, erratum 3324346
  https://developer.arm.com/documentation/SDEN-1707914/1600/

* Neoverse-N1 (MP050) SDEN v32.0, erratum 3324349
  https://developer.arm.com/documentation/SDEN-885747/3200/

* Neoverse-V1 (MP076) SDEN v19.0, erratum 3324341
  https://developer.arm.com/documentation/SDEN-1401781/1900/

Note that due to the manner in which Arm develops IP and tracks errata,
some CPUs share a common erratum number and some CPUs have multiple
erratum numbers for the same HW issue.

On parts without SB, it is necessary to use ISB for the workaround. The
spec_bar() macro used in the mitigation will expand to a "DSB SY; ISB"
sequence in this case, which is sufficient on all affected parts.

Enable the existing mitigation by adding the relevant MIDRs to
erratum_spec_ssbs_list. The list is sorted alphanumerically (involving
moving Neoverse-V3 after Neoverse-V2) so that this is easy to audit and
potentially extend again in future. The Kconfig text is also updated to
clarify the set of affected parts and the mitigation.

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: James Morse &lt;james.morse@arm.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Reviewed-by: Anshuman Khandual &lt;anshuman.khandual@arm.com&gt;
Acked-by: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/r/20240801101803.1982459-4-mark.rutland@arm.com
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
[ Mark: fix conflicts in silicon-errata.rst ]
Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: errata: Expand speculative SSBS workaround</title>
<updated>2024-08-19T03:33:49+00:00</updated>
<author>
<name>Mark Rutland</name>
<email>mark.rutland@arm.com</email>
</author>
<published>2024-08-09T10:34:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d19a135ca282a1fd781eaff7187177346433b31b'/>
<id>d19a135ca282a1fd781eaff7187177346433b31b</id>
<content type='text'>
[ Upstream commit 75b3c43eab594bfbd8184ec8ee1a6b820950819a ]

A number of Arm Ltd CPUs suffer from errata whereby an MSR to the SSBS
special-purpose register does not affect subsequent speculative
instructions, permitting speculative store bypassing for a window of
time.

We worked around this for Cortex-X4 and Neoverse-V3, in commit:

  7187bb7d0b5c7dfa ("arm64: errata: Add workaround for Arm errata 3194386 and 3312417")

... as per their Software Developer Errata Notice (SDEN) documents:

* Cortex-X4 SDEN v8.0, erratum 3194386:
  https://developer.arm.com/documentation/SDEN-2432808/0800/

* Neoverse-V3 SDEN v6.0, erratum 3312417:
  https://developer.arm.com/documentation/SDEN-2891958/0600/

Since then, similar errata have been published for a number of other Arm Ltd
CPUs, for which the mitigation is the same. This is described in their
respective SDEN documents:

* Cortex-A710 SDEN v19.0, errataum 3324338
  https://developer.arm.com/documentation/SDEN-1775101/1900/?lang=en

* Cortex-A720 SDEN v11.0, erratum 3456091
  https://developer.arm.com/documentation/SDEN-2439421/1100/?lang=en

* Cortex-X2 SDEN v19.0, erratum 3324338
  https://developer.arm.com/documentation/SDEN-1775100/1900/?lang=en

* Cortex-X3 SDEN v14.0, erratum 3324335
  https://developer.arm.com/documentation/SDEN-2055130/1400/?lang=en

* Cortex-X925 SDEN v8.0, erratum 3324334
  https://developer.arm.com/documentation/109108/800/?lang=en

* Neoverse-N2 SDEN v17.0, erratum 3324339
  https://developer.arm.com/documentation/SDEN-1982442/1700/?lang=en

* Neoverse-V2 SDEN v9.0, erratum 3324336
  https://developer.arm.com/documentation/SDEN-2332927/900/?lang=en

Note that due to shared design lineage, some CPUs share the same erratum
number.

Add these to the existing mitigation under CONFIG_ARM64_ERRATUM_3194386.
As listing all of the erratum IDs in the runtime description would be
unwieldy, this is reduced to:

	"SSBS not fully self-synchronizing"

... matching the description of the errata in all of the SDENs.

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: James Morse &lt;james.morse@arm.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/r/20240603111812.1514101-6-mark.rutland@arm.com
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
[ Mark: fix conflicts and renames ]
Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 75b3c43eab594bfbd8184ec8ee1a6b820950819a ]

A number of Arm Ltd CPUs suffer from errata whereby an MSR to the SSBS
special-purpose register does not affect subsequent speculative
instructions, permitting speculative store bypassing for a window of
time.

We worked around this for Cortex-X4 and Neoverse-V3, in commit:

  7187bb7d0b5c7dfa ("arm64: errata: Add workaround for Arm errata 3194386 and 3312417")

... as per their Software Developer Errata Notice (SDEN) documents:

* Cortex-X4 SDEN v8.0, erratum 3194386:
  https://developer.arm.com/documentation/SDEN-2432808/0800/

* Neoverse-V3 SDEN v6.0, erratum 3312417:
  https://developer.arm.com/documentation/SDEN-2891958/0600/

Since then, similar errata have been published for a number of other Arm Ltd
CPUs, for which the mitigation is the same. This is described in their
respective SDEN documents:

* Cortex-A710 SDEN v19.0, errataum 3324338
  https://developer.arm.com/documentation/SDEN-1775101/1900/?lang=en

* Cortex-A720 SDEN v11.0, erratum 3456091
  https://developer.arm.com/documentation/SDEN-2439421/1100/?lang=en

* Cortex-X2 SDEN v19.0, erratum 3324338
  https://developer.arm.com/documentation/SDEN-1775100/1900/?lang=en

* Cortex-X3 SDEN v14.0, erratum 3324335
  https://developer.arm.com/documentation/SDEN-2055130/1400/?lang=en

* Cortex-X925 SDEN v8.0, erratum 3324334
  https://developer.arm.com/documentation/109108/800/?lang=en

* Neoverse-N2 SDEN v17.0, erratum 3324339
  https://developer.arm.com/documentation/SDEN-1982442/1700/?lang=en

* Neoverse-V2 SDEN v9.0, erratum 3324336
  https://developer.arm.com/documentation/SDEN-2332927/900/?lang=en

Note that due to shared design lineage, some CPUs share the same erratum
number.

Add these to the existing mitigation under CONFIG_ARM64_ERRATUM_3194386.
As listing all of the erratum IDs in the runtime description would be
unwieldy, this is reduced to:

	"SSBS not fully self-synchronizing"

... matching the description of the errata in all of the SDENs.

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: James Morse &lt;james.morse@arm.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/r/20240603111812.1514101-6-mark.rutland@arm.com
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
[ Mark: fix conflicts and renames ]
Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: errata: Unify speculative SSBS errata logic</title>
<updated>2024-08-19T03:33:49+00:00</updated>
<author>
<name>Mark Rutland</name>
<email>mark.rutland@arm.com</email>
</author>
<published>2024-08-09T10:34:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=31c04d3f6870ad64b02ca1d676a63aa68860a07c'/>
<id>31c04d3f6870ad64b02ca1d676a63aa68860a07c</id>
<content type='text'>
[ Upstream commit ec768766608092087dfb5c1fc45a16a6f524dee2 ]

Cortex-X4 erratum 3194386 and Neoverse-V3 erratum 3312417 are identical,
with duplicate Kconfig text and some unsightly ifdeffery. While we try
to share code behind CONFIG_ARM64_WORKAROUND_SPECULATIVE_SSBS, having
separate options results in a fair amount of boilerplate code, and this
will only get worse as we expand the set of affected CPUs.

To reduce this boilerplate, unify the two behind a common Kconfig
option. This removes the duplicate text and Kconfig logic, and removes
the need for the intermediate ARM64_WORKAROUND_SPECULATIVE_SSBS option.
The set of affected CPUs is described as a list so that this can easily
be extended.

I've used ARM64_ERRATUM_3194386 (matching the Neoverse-V3 erratum ID) as
the common option, matching the way we use ARM64_ERRATUM_1319367 to
cover Cortex-A57 erratum 1319537 and Cortex-A72 erratum 1319367.

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: James Morse &lt;james.morse@arm.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/r/20240603111812.1514101-5-mark.rutland@arm.com
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
[ Mark: fix conflicts &amp; renames, drop unneeded cpucaps.h ]
Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit ec768766608092087dfb5c1fc45a16a6f524dee2 ]

Cortex-X4 erratum 3194386 and Neoverse-V3 erratum 3312417 are identical,
with duplicate Kconfig text and some unsightly ifdeffery. While we try
to share code behind CONFIG_ARM64_WORKAROUND_SPECULATIVE_SSBS, having
separate options results in a fair amount of boilerplate code, and this
will only get worse as we expand the set of affected CPUs.

To reduce this boilerplate, unify the two behind a common Kconfig
option. This removes the duplicate text and Kconfig logic, and removes
the need for the intermediate ARM64_WORKAROUND_SPECULATIVE_SSBS option.
The set of affected CPUs is described as a list so that this can easily
be extended.

I've used ARM64_ERRATUM_3194386 (matching the Neoverse-V3 erratum ID) as
the common option, matching the way we use ARM64_ERRATUM_1319367 to
cover Cortex-A57 erratum 1319537 and Cortex-A72 erratum 1319367.

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: James Morse &lt;james.morse@arm.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/r/20240603111812.1514101-5-mark.rutland@arm.com
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
[ Mark: fix conflicts &amp; renames, drop unneeded cpucaps.h ]
Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: errata: Add workaround for Arm errata 3194386 and 3312417</title>
<updated>2024-08-19T03:33:49+00:00</updated>
<author>
<name>Mark Rutland</name>
<email>mark.rutland@arm.com</email>
</author>
<published>2024-08-09T10:34:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=60bb45497476d139efafe7b97c3b5318b9a6cdc5'/>
<id>60bb45497476d139efafe7b97c3b5318b9a6cdc5</id>
<content type='text'>
[ Upstream commit 7187bb7d0b5c7dfa18ca82e9e5c75e13861b1d88 ]

Cortex-X4 and Neoverse-V3 suffer from errata whereby an MSR to the SSBS
special-purpose register does not affect subsequent speculative
instructions, permitting speculative store bypassing for a window of
time. This is described in their Software Developer Errata Notice (SDEN)
documents:

* Cortex-X4 SDEN v8.0, erratum 3194386:
  https://developer.arm.com/documentation/SDEN-2432808/0800/

* Neoverse-V3 SDEN v6.0, erratum 3312417:
  https://developer.arm.com/documentation/SDEN-2891958/0600/

To workaround these errata, it is necessary to place a speculation
barrier (SB) after MSR to the SSBS special-purpose register. This patch
adds the requisite SB after writes to SSBS within the kernel, and hides
the presence of SSBS from EL0 such that userspace software which cares
about SSBS will manipulate this via prctl(PR_GET_SPECULATION_CTRL, ...).

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: James Morse &lt;james.morse@arm.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/r/20240508081400.235362-5-mark.rutland@arm.com
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
[ Mark: fix conflicts &amp; renames, drop unneeded cpucaps.h, fold in user_feature_fixup() ]
Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 7187bb7d0b5c7dfa18ca82e9e5c75e13861b1d88 ]

Cortex-X4 and Neoverse-V3 suffer from errata whereby an MSR to the SSBS
special-purpose register does not affect subsequent speculative
instructions, permitting speculative store bypassing for a window of
time. This is described in their Software Developer Errata Notice (SDEN)
documents:

* Cortex-X4 SDEN v8.0, erratum 3194386:
  https://developer.arm.com/documentation/SDEN-2432808/0800/

* Neoverse-V3 SDEN v6.0, erratum 3312417:
  https://developer.arm.com/documentation/SDEN-2891958/0600/

To workaround these errata, it is necessary to place a speculation
barrier (SB) after MSR to the SSBS special-purpose register. This patch
adds the requisite SB after writes to SSBS within the kernel, and hides
the presence of SSBS from EL0 such that userspace software which cares
about SSBS will manipulate this via prctl(PR_GET_SPECULATION_CTRL, ...).

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: James Morse &lt;james.morse@arm.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/r/20240508081400.235362-5-mark.rutland@arm.com
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
[ Mark: fix conflicts &amp; renames, drop unneeded cpucaps.h, fold in user_feature_fixup() ]
Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ASoC: dt-bindings: rt5645: add cbj sleeve gpio property</title>
<updated>2024-06-16T11:28:31+00:00</updated>
<author>
<name>Derek Fang</name>
<email>derek.fang@realtek.com</email>
</author>
<published>2024-04-08T09:10:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b159bd7fa8dc0b1b8a0f97c0f2ba2f562d940ef6'/>
<id>b159bd7fa8dc0b1b8a0f97c0f2ba2f562d940ef6</id>
<content type='text'>
[ Upstream commit 306b38e3fa727d22454a148a364123709e356600 ]

Add an optional gpio property to control external CBJ circuits
to avoid some electric noise caused by sleeve/ring2 contacts floating.

Signed-off-by: Derek Fang &lt;derek.fang@realtek.com&gt;

Link: https://msgid.link/r/20240408091057.14165-2-derek.fang@realtek.com
Signed-off-by: Mark Brown &lt;broonie@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 306b38e3fa727d22454a148a364123709e356600 ]

Add an optional gpio property to control external CBJ circuits
to avoid some electric noise caused by sleeve/ring2 contacts floating.

Signed-off-by: Derek Fang &lt;derek.fang@realtek.com&gt;

Link: https://msgid.link/r/20240408091057.14165-2-derek.fang@realtek.com
Signed-off-by: Mark Brown &lt;broonie@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>docs: kernel_include.py: Cope with docutils 0.21</title>
<updated>2024-05-25T14:17:18+00:00</updated>
<author>
<name>Akira Yokosawa</name>
<email>akiyks@gmail.com</email>
</author>
<published>2024-05-01T03:16:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2b21f3095bbee73bc12b28296ab4728ccae1e68a'/>
<id>2b21f3095bbee73bc12b28296ab4728ccae1e68a</id>
<content type='text'>
commit d43ddd5c91802a46354fa4c4381416ef760676e2 upstream.

Running "make htmldocs" on a newly installed Sphinx 7.3.7 ends up in
a build error:

    Sphinx parallel build error:
    AttributeError: module 'docutils.nodes' has no attribute 'reprunicode'

docutils 0.21 has removed nodes.reprunicode, quote from release note [1]:

  * Removed objects:

    docutils.nodes.reprunicode, docutils.nodes.ensure_str()
        Python 2 compatibility hacks

Sphinx 7.3.0 supports docutils 0.21 [2]:

kernel_include.py, whose origin is misc.py of docutils, uses reprunicode.

Upstream docutils removed the offending line from the corresponding file
(docutils/docutils/parsers/rst/directives/misc.py) in January 2022.
Quoting the changelog [3]:

    Deprecate `nodes.reprunicode` and `nodes.ensure_str()`.

    Drop uses of the deprecated constructs (not required with Python 3).

Do the same for kernel_include.py.

Tested against:
  - Sphinx 2.4.5 (docutils 0.17.1)
  - Sphinx 3.4.3 (docutils 0.17.1)
  - Sphinx 5.3.0 (docutils 0.18.1)
  - Sphinx 6.2.1 (docutils 0.19)
  - Sphinx 7.2.6 (docutils 0.20.1)
  - Sphinx 7.3.7 (docutils 0.21.2)

Link: http://www.docutils.org/RELEASE-NOTES.html#release-0-21-2024-04-09 [1]
Link: https://www.sphinx-doc.org/en/master/changes.html#release-7-3-0-released-apr-16-2024 [2]
Link: https://github.com/docutils/docutils/commit/c8471ce47a24 [3]
Signed-off-by: Akira Yokosawa &lt;akiyks@gmail.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Jonathan Corbet &lt;corbet@lwn.net&gt;
Link: https://lore.kernel.org/r/faf5fa45-2a9d-4573-9d2e-3930bdc1ed65@gmail.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit d43ddd5c91802a46354fa4c4381416ef760676e2 upstream.

Running "make htmldocs" on a newly installed Sphinx 7.3.7 ends up in
a build error:

    Sphinx parallel build error:
    AttributeError: module 'docutils.nodes' has no attribute 'reprunicode'

docutils 0.21 has removed nodes.reprunicode, quote from release note [1]:

  * Removed objects:

    docutils.nodes.reprunicode, docutils.nodes.ensure_str()
        Python 2 compatibility hacks

Sphinx 7.3.0 supports docutils 0.21 [2]:

kernel_include.py, whose origin is misc.py of docutils, uses reprunicode.

Upstream docutils removed the offending line from the corresponding file
(docutils/docutils/parsers/rst/directives/misc.py) in January 2022.
Quoting the changelog [3]:

    Deprecate `nodes.reprunicode` and `nodes.ensure_str()`.

    Drop uses of the deprecated constructs (not required with Python 3).

Do the same for kernel_include.py.

Tested against:
  - Sphinx 2.4.5 (docutils 0.17.1)
  - Sphinx 3.4.3 (docutils 0.17.1)
  - Sphinx 5.3.0 (docutils 0.18.1)
  - Sphinx 6.2.1 (docutils 0.19)
  - Sphinx 7.2.6 (docutils 0.20.1)
  - Sphinx 7.3.7 (docutils 0.21.2)

Link: http://www.docutils.org/RELEASE-NOTES.html#release-0-21-2024-04-09 [1]
Link: https://www.sphinx-doc.org/en/master/changes.html#release-7-3-0-released-apr-16-2024 [2]
Link: https://github.com/docutils/docutils/commit/c8471ce47a24 [3]
Signed-off-by: Akira Yokosawa &lt;akiyks@gmail.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Jonathan Corbet &lt;corbet@lwn.net&gt;
Link: https://lore.kernel.org/r/faf5fa45-2a9d-4573-9d2e-3930bdc1ed65@gmail.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/cpu: Enable STIBP on AMD if Automatic IBRS is enabled</title>
<updated>2024-04-13T10:51:32+00:00</updated>
<author>
<name>Kim Phillips</name>
<email>kim.phillips@amd.com</email>
</author>
<published>2023-07-20T19:47:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=fa24c1a49d931ce78ac77d63cf809e425f3560ea'/>
<id>fa24c1a49d931ce78ac77d63cf809e425f3560ea</id>
<content type='text'>
commit fd470a8beed88440b160d690344fbae05a0b9b1b upstream.

Unlike Intel's Enhanced IBRS feature, AMD's Automatic IBRS does not
provide protection to processes running at CPL3/user mode, see section
"Extended Feature Enable Register (EFER)" in the APM v2 at
https://bugzilla.kernel.org/attachment.cgi?id=304652

Explicitly enable STIBP to protect against cross-thread CPL3
branch target injections on systems with Automatic IBRS enabled.

Also update the relevant documentation.

Fixes: e7862eda309e ("x86/cpu: Support AMD Automatic IBRS")
Reported-by: Tom Lendacky &lt;thomas.lendacky@amd.com&gt;
Signed-off-by: Kim Phillips &lt;kim.phillips@amd.com&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230720194727.67022-1-kim.phillips@amd.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit fd470a8beed88440b160d690344fbae05a0b9b1b upstream.

Unlike Intel's Enhanced IBRS feature, AMD's Automatic IBRS does not
provide protection to processes running at CPL3/user mode, see section
"Extended Feature Enable Register (EFER)" in the APM v2 at
https://bugzilla.kernel.org/attachment.cgi?id=304652

Explicitly enable STIBP to protect against cross-thread CPL3
branch target injections on systems with Automatic IBRS enabled.

Also update the relevant documentation.

Fixes: e7862eda309e ("x86/cpu: Support AMD Automatic IBRS")
Reported-by: Tom Lendacky &lt;thomas.lendacky@amd.com&gt;
Signed-off-by: Kim Phillips &lt;kim.phillips@amd.com&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230720194727.67022-1-kim.phillips@amd.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/cpu: Support AMD Automatic IBRS</title>
<updated>2024-04-13T10:51:21+00:00</updated>
<author>
<name>Kim Phillips</name>
<email>kim.phillips@amd.com</email>
</author>
<published>2023-01-24T16:33:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=922bc61d8c43b21cd399be8ce24c0da191e64fbc'/>
<id>922bc61d8c43b21cd399be8ce24c0da191e64fbc</id>
<content type='text'>
commit e7862eda309ecfccc36bb5558d937ed3ace07f3f upstream.

The AMD Zen4 core supports a new feature called Automatic IBRS.

It is a "set-and-forget" feature that means that, like Intel's Enhanced IBRS,
h/w manages its IBRS mitigation resources automatically across CPL transitions.

The feature is advertised by CPUID_Fn80000021_EAX bit 8 and is enabled by
setting MSR C000_0080 (EFER) bit 21.

Enable Automatic IBRS by default if the CPU feature is present.  It typically
provides greater performance over the incumbent generic retpolines mitigation.

Reuse the SPECTRE_V2_EIBRS spectre_v2_mitigation enum.  AMD Automatic IBRS and
Intel Enhanced IBRS have similar enablement.  Add NO_EIBRS_PBRSB to
cpu_vuln_whitelist, since AMD Automatic IBRS isn't affected by PBRSB-eIBRS.

The kernel command line option spectre_v2=eibrs is used to select AMD Automatic
IBRS, if available.

Signed-off-by: Kim Phillips &lt;kim.phillips@amd.com&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Acked-by: Sean Christopherson &lt;seanjc@google.com&gt;
Acked-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Link: https://lore.kernel.org/r/20230124163319.2277355-8-kim.phillips@amd.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit e7862eda309ecfccc36bb5558d937ed3ace07f3f upstream.

The AMD Zen4 core supports a new feature called Automatic IBRS.

It is a "set-and-forget" feature that means that, like Intel's Enhanced IBRS,
h/w manages its IBRS mitigation resources automatically across CPL transitions.

The feature is advertised by CPUID_Fn80000021_EAX bit 8 and is enabled by
setting MSR C000_0080 (EFER) bit 21.

Enable Automatic IBRS by default if the CPU feature is present.  It typically
provides greater performance over the incumbent generic retpolines mitigation.

Reuse the SPECTRE_V2_EIBRS spectre_v2_mitigation enum.  AMD Automatic IBRS and
Intel Enhanced IBRS have similar enablement.  Add NO_EIBRS_PBRSB to
cpu_vuln_whitelist, since AMD Automatic IBRS isn't affected by PBRSB-eIBRS.

The kernel command line option spectre_v2=eibrs is used to select AMD Automatic
IBRS, if available.

Signed-off-by: Kim Phillips &lt;kim.phillips@amd.com&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Acked-by: Sean Christopherson &lt;seanjc@google.com&gt;
Acked-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Link: https://lore.kernel.org/r/20230124163319.2277355-8-kim.phillips@amd.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Documentation/hw-vuln: Update spectre doc</title>
<updated>2024-04-13T10:51:21+00:00</updated>
<author>
<name>Lin Yujun</name>
<email>linyujun809@huawei.com</email>
</author>
<published>2022-08-30T12:36:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d9caea5f1bfe20357b7c5291a2e990bfaf17ea4a'/>
<id>d9caea5f1bfe20357b7c5291a2e990bfaf17ea4a</id>
<content type='text'>
commit 06cb31cc761823ef444ba4e1df11347342a6e745 upstream.

commit 7c693f54c873691 ("x86/speculation: Add spectre_v2=ibrs option to support Kernel IBRS")

adds the "ibrs " option  in
Documentation/admin-guide/kernel-parameters.txt but omits it to
Documentation/admin-guide/hw-vuln/spectre.rst, add it.

Signed-off-by: Lin Yujun &lt;linyujun809@huawei.com&gt;
Link: https://lore.kernel.org/r/20220830123614.23007-1-linyujun809@huawei.com
Signed-off-by: Jonathan Corbet &lt;corbet@lwn.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 06cb31cc761823ef444ba4e1df11347342a6e745 upstream.

commit 7c693f54c873691 ("x86/speculation: Add spectre_v2=ibrs option to support Kernel IBRS")

adds the "ibrs " option  in
Documentation/admin-guide/kernel-parameters.txt but omits it to
Documentation/admin-guide/hw-vuln/spectre.rst, add it.

Signed-off-by: Lin Yujun &lt;linyujun809@huawei.com&gt;
Link: https://lore.kernel.org/r/20220830123614.23007-1-linyujun809@huawei.com
Signed-off-by: Jonathan Corbet &lt;corbet@lwn.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
