<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/base, branch v5.18.3</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>drivers/base/memory: fix an unlikely reference counting issue in __add_memory_block()</title>
<updated>2022-06-09T08:30:28+00:00</updated>
<author>
<name>Christophe JAILLET</name>
<email>christophe.jaillet@wanadoo.fr</email>
</author>
<published>2022-04-29T06:16:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a8629e4fd416db62507adbee04604451cedcf6c4'/>
<id>a8629e4fd416db62507adbee04604451cedcf6c4</id>
<content type='text'>
[ Upstream commit f47f758cff59c68015d6b9b9c077110df7c2c828 ]

__add_memory_block() calls both put_device() and device_unregister() when
storing the memory block into the xarray.  This is incorrect because
xarray doesn't take an additional reference and device_unregister()
already calls put_device().

Triggering the issue looks really unlikely and its only effect should be
to log a spurious warning about a ref counted issue.

Link: https://lkml.kernel.org/r/d44c63d78affe844f020dc02ad6af29abc448fc4.1650611702.git.christophe.jaillet@wanadoo.fr
Fixes: 4fb6eabf1037 ("drivers/base/memory.c: cache memory blocks in xarray to accelerate lookup")
Signed-off-by: Christophe JAILLET &lt;christophe.jaillet@wanadoo.fr&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Reviewed-by: David Hildenbrand &lt;david@redhat.com&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: "Rafael J. Wysocki" &lt;rafael@kernel.org&gt;
Cc: Scott Cheloha &lt;cheloha@linux.vnet.ibm.com&gt;
Cc: Nathan Lynch &lt;nathanl@linux.ibm.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.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 f47f758cff59c68015d6b9b9c077110df7c2c828 ]

__add_memory_block() calls both put_device() and device_unregister() when
storing the memory block into the xarray.  This is incorrect because
xarray doesn't take an additional reference and device_unregister()
already calls put_device().

Triggering the issue looks really unlikely and its only effect should be
to log a spurious warning about a ref counted issue.

Link: https://lkml.kernel.org/r/d44c63d78affe844f020dc02ad6af29abc448fc4.1650611702.git.christophe.jaillet@wanadoo.fr
Fixes: 4fb6eabf1037 ("drivers/base/memory.c: cache memory blocks in xarray to accelerate lookup")
Signed-off-by: Christophe JAILLET &lt;christophe.jaillet@wanadoo.fr&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Reviewed-by: David Hildenbrand &lt;david@redhat.com&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: "Rafael J. Wysocki" &lt;rafael@kernel.org&gt;
Cc: Scott Cheloha &lt;cheloha@linux.vnet.ibm.com&gt;
Cc: Nathan Lynch &lt;nathanl@linux.ibm.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drivers/base/node.c: fix compaction sysfs file leak</title>
<updated>2022-06-09T08:30:27+00:00</updated>
<author>
<name>Miaohe Lin</name>
<email>linmiaohe@huawei.com</email>
</author>
<published>2022-04-29T06:16:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6905be93d1ab54f73718047536fec0ca488d5315'/>
<id>6905be93d1ab54f73718047536fec0ca488d5315</id>
<content type='text'>
[ Upstream commit da63dc84befaa9e6079a0bc363ff0eaa975f9073 ]

Compaction sysfs file is created via compaction_register_node in
register_node.  But we forgot to remove it in unregister_node.  Thus
compaction sysfs file is leaked.  Using compaction_unregister_node to fix
this issue.

Link: https://lkml.kernel.org/r/20220401070905.43679-1-linmiaohe@huawei.com
Fixes: ed4a6d7f0676 ("mm: compaction: add /sys trigger for per-node memory compaction")
Signed-off-by: Miaohe Lin &lt;linmiaohe@huawei.com&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: Rafael J. Wysocki &lt;rafael@kernel.org&gt;
Cc: Mel Gorman &lt;mel@csn.ul.ie&gt;
Cc: Minchan Kim &lt;minchan.kim@gmail.com&gt;
Cc: KAMEZAWA Hiroyuki &lt;kamezawa.hiroyu@jp.fujitsu.com&gt;
Cc: KOSAKI Motohiro &lt;kosaki.motohiro@jp.fujitsu.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.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 da63dc84befaa9e6079a0bc363ff0eaa975f9073 ]

Compaction sysfs file is created via compaction_register_node in
register_node.  But we forgot to remove it in unregister_node.  Thus
compaction sysfs file is leaked.  Using compaction_unregister_node to fix
this issue.

Link: https://lkml.kernel.org/r/20220401070905.43679-1-linmiaohe@huawei.com
Fixes: ed4a6d7f0676 ("mm: compaction: add /sys trigger for per-node memory compaction")
Signed-off-by: Miaohe Lin &lt;linmiaohe@huawei.com&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: Rafael J. Wysocki &lt;rafael@kernel.org&gt;
Cc: Mel Gorman &lt;mel@csn.ul.ie&gt;
Cc: Minchan Kim &lt;minchan.kim@gmail.com&gt;
Cc: KAMEZAWA Hiroyuki &lt;kamezawa.hiroyu@jp.fujitsu.com&gt;
Cc: KOSAKI Motohiro &lt;kosaki.motohiro@jp.fujitsu.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>PM: domains: Fix initialization of genpd's next_wakeup</title>
<updated>2022-06-09T08:30:18+00:00</updated>
<author>
<name>Ulf Hansson</name>
<email>ulf.hansson@linaro.org</email>
</author>
<published>2022-05-11T14:57:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1def4493ccd75b921b10d40e4f425c684f1c87f4'/>
<id>1def4493ccd75b921b10d40e4f425c684f1c87f4</id>
<content type='text'>
[ Upstream commit 622d9b5577f19a6472db21df042fea8f5fefe244 ]

In the genpd governor we walk the list of child-domains to take into
account their next_wakeup. If the child-domain itself, doesn't have a
governor assigned to it, we can end up using the next_wakeup value before
it has been properly initialized. To prevent a possible incorrect behaviour
in the governor, let's initialize next_wakeup to KTIME_MAX.

Fixes: c79aa080fb0f ("PM: domains: use device's next wakeup to determine domain idle state")
Signed-off-by: Ulf Hansson &lt;ulf.hansson@linaro.org&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.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 622d9b5577f19a6472db21df042fea8f5fefe244 ]

In the genpd governor we walk the list of child-domains to take into
account their next_wakeup. If the child-domain itself, doesn't have a
governor assigned to it, we can end up using the next_wakeup value before
it has been properly initialized. To prevent a possible incorrect behaviour
in the governor, let's initialize next_wakeup to KTIME_MAX.

Fixes: c79aa080fb0f ("PM: domains: use device's next wakeup to determine domain idle state")
Signed-off-by: Ulf Hansson &lt;ulf.hansson@linaro.org&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>device property: Allow error pointer to be passed to fwnode APIs</title>
<updated>2022-06-09T08:29:58+00:00</updated>
<author>
<name>Andy Shevchenko</name>
<email>andriy.shevchenko@linux.intel.com</email>
</author>
<published>2022-04-08T18:48:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=01a0e3fbf13bae2cd277e731284171b501aa6895'/>
<id>01a0e3fbf13bae2cd277e731284171b501aa6895</id>
<content type='text'>
[ Upstream commit 002752af7b89b74c64fe6bec8c5fde3d3a7810d8 ]

Some of the fwnode APIs might return an error pointer instead of NULL
or valid fwnode handle. The result of such API call may be considered
optional and hence the test for it is usually done in a form of

	fwnode = fwnode_find_reference(...);
	if (IS_ERR(fwnode))
		...error handling...

Nevertheless the resulting fwnode may have bumped the reference count
and hence caller of the above API is obliged to call fwnode_handle_put().
Since fwnode may be not valid either as NULL or error pointer the check
has to be performed there. This approach uglifies the code and adds
a point of making a mistake, i.e. forgetting about error point case.

To prevent this, allow an error pointer to be passed to the fwnode APIs.

Fixes: 83b34afb6b79 ("device property: Introduce fwnode_find_reference()")
Reported-by: Nuno Sá &lt;nuno.sa@analog.com&gt;
Tested-by: Nuno Sá &lt;nuno.sa@analog.com&gt;
Acked-by: Nuno Sá &lt;nuno.sa@analog.com&gt;
Reviewed-by: Sakari Ailus &lt;sakari.ailus@linux.intel.com&gt;
Reviewed-by: Heikki Krogerus &lt;heikki.krogerus@linux.intel.com&gt;
Signed-off-by: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Tested-by: Michael Walle &lt;michael@walle.cc&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.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 002752af7b89b74c64fe6bec8c5fde3d3a7810d8 ]

Some of the fwnode APIs might return an error pointer instead of NULL
or valid fwnode handle. The result of such API call may be considered
optional and hence the test for it is usually done in a form of

	fwnode = fwnode_find_reference(...);
	if (IS_ERR(fwnode))
		...error handling...

Nevertheless the resulting fwnode may have bumped the reference count
and hence caller of the above API is obliged to call fwnode_handle_put().
Since fwnode may be not valid either as NULL or error pointer the check
has to be performed there. This approach uglifies the code and adds
a point of making a mistake, i.e. forgetting about error point case.

To prevent this, allow an error pointer to be passed to the fwnode APIs.

Fixes: 83b34afb6b79 ("device property: Introduce fwnode_find_reference()")
Reported-by: Nuno Sá &lt;nuno.sa@analog.com&gt;
Tested-by: Nuno Sá &lt;nuno.sa@analog.com&gt;
Acked-by: Nuno Sá &lt;nuno.sa@analog.com&gt;
Reviewed-by: Sakari Ailus &lt;sakari.ailus@linux.intel.com&gt;
Reviewed-by: Heikki Krogerus &lt;heikki.krogerus@linux.intel.com&gt;
Signed-off-by: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Tested-by: Michael Walle &lt;michael@walle.cc&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>firmware_loader: use kernel credentials when reading firmware</title>
<updated>2022-05-06T08:00:03+00:00</updated>
<author>
<name>Thiébaud Weksteen</name>
<email>tweek@google.com</email>
</author>
<published>2022-05-02T00:49:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=581dd69830341d299b0c097fc366097ab497d679'/>
<id>581dd69830341d299b0c097fc366097ab497d679</id>
<content type='text'>
Device drivers may decide to not load firmware when probed to avoid
slowing down the boot process should the firmware filesystem not be
available yet. In this case, the firmware loading request may be done
when a device file associated with the driver is first accessed. The
credentials of the userspace process accessing the device file may be
used to validate access to the firmware files requested by the driver.
Ensure that the kernel assumes the responsibility of reading the
firmware.

This was observed on Android for a graphic driver loading their firmware
when the device file (e.g. /dev/mali0) was first opened by userspace
(i.e. surfaceflinger). The security context of surfaceflinger was used
to validate the access to the firmware file (e.g.
/vendor/firmware/mali.bin).

Previously, Android configurations were not setting up the
firmware_class.path command line argument and were relying on the
userspace fallback mechanism. In this case, the security context of the
userspace daemon (i.e. ueventd) was consistently used to read firmware
files. More Android devices are now found to set firmware_class.path
which gives the kernel the opportunity to read the firmware directly
(via kernel_read_file_from_path_initns). In this scenario, the current
process credentials were used, even if unrelated to the loading of the
firmware file.

Signed-off-by: Thiébaud Weksteen &lt;tweek@google.com&gt;
Cc: &lt;stable@vger.kernel.org&gt; # 5.10
Reviewed-by: Paul Moore &lt;paul@paul-moore.com&gt;
Acked-by: Luis Chamberlain &lt;mcgrof@kernel.org&gt;
Link: https://lore.kernel.org/r/20220502004952.3970800-1-tweek@google.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>
Device drivers may decide to not load firmware when probed to avoid
slowing down the boot process should the firmware filesystem not be
available yet. In this case, the firmware loading request may be done
when a device file associated with the driver is first accessed. The
credentials of the userspace process accessing the device file may be
used to validate access to the firmware files requested by the driver.
Ensure that the kernel assumes the responsibility of reading the
firmware.

This was observed on Android for a graphic driver loading their firmware
when the device file (e.g. /dev/mali0) was first opened by userspace
(i.e. surfaceflinger). The security context of surfaceflinger was used
to validate the access to the firmware file (e.g.
/vendor/firmware/mali.bin).

Previously, Android configurations were not setting up the
firmware_class.path command line argument and were relying on the
userspace fallback mechanism. In this case, the security context of the
userspace daemon (i.e. ueventd) was consistently used to read firmware
files. More Android devices are now found to set firmware_class.path
which gives the kernel the opportunity to read the firmware directly
(via kernel_read_file_from_path_initns). In this scenario, the current
process credentials were used, even if unrelated to the loading of the
firmware file.

Signed-off-by: Thiébaud Weksteen &lt;tweek@google.com&gt;
Cc: &lt;stable@vger.kernel.org&gt; # 5.10
Reviewed-by: Paul Moore &lt;paul@paul-moore.com&gt;
Acked-by: Luis Chamberlain &lt;mcgrof@kernel.org&gt;
Link: https://lore.kernel.org/r/20220502004952.3970800-1-tweek@google.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'driver-core-5.18-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core</title>
<updated>2022-04-30T17:24:21+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-04-30T17:24:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=57ae8a492116910bad2b3497ffe555b3a4b4180f'/>
<id>57ae8a492116910bad2b3497ffe555b3a4b4180f</id>
<content type='text'>
Pull driver core fixes from Greg KH:
 "Here are some small driver core and kernfs fixes for some reported
  problems. They include:

   - kernfs regression that is causing oopses in 5.17 and newer releases

   - topology sysfs fixes for a few small reported problems.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'driver-core-5.18-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  kernfs: fix NULL dereferencing in kernfs_remove
  topology: Fix up build warning in topology_is_visible()
  arch_topology: Do not set llc_sibling if llc_id is invalid
  topology: make core_mask include at least cluster_siblings
  topology/sysfs: Hide PPIN on systems that do not support it.
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull driver core fixes from Greg KH:
 "Here are some small driver core and kernfs fixes for some reported
  problems. They include:

   - kernfs regression that is causing oopses in 5.17 and newer releases

   - topology sysfs fixes for a few small reported problems.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'driver-core-5.18-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  kernfs: fix NULL dereferencing in kernfs_remove
  topology: Fix up build warning in topology_is_visible()
  arch_topology: Do not set llc_sibling if llc_id is invalid
  topology: make core_mask include at least cluster_siblings
  topology/sysfs: Hide PPIN on systems that do not support it.
</pre>
</div>
</content>
</entry>
<entry>
<title>topology: Fix up build warning in topology_is_visible()</title>
<updated>2022-04-23T10:53:11+00:00</updated>
<author>
<name>Greg Kroah-Hartman</name>
<email>gregkh@linuxfoundation.org</email>
</author>
<published>2022-04-22T06:26:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c95ce3a23dcda678f6f7811dd39b6d14eeb6f192'/>
<id>c95ce3a23dcda678f6f7811dd39b6d14eeb6f192</id>
<content type='text'>
Commit aa63a74d4535 ("topology/sysfs: Hide PPIN on systems that do not
support it.") caused a build warning on some configurations:

drivers/base/topology.c: In function 'topology_is_visible':
drivers/base/topology.c:158:24: warning: unused variable 'dev' [-Wunused-variable]
  158 |         struct device *dev = kobj_to_dev(kobj);

Fix this up by getting rid of the variable entirely.

Fixes: aa63a74d4535 ("topology/sysfs: Hide PPIN on systems that do not support it.")
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Reported-by: Stephen Rothwell &lt;sfr@canb.auug.org.au&gt;
Link: https://lore.kernel.org/r/20220422062653.3899972-1-gregkh@linuxfoundation.org
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 aa63a74d4535 ("topology/sysfs: Hide PPIN on systems that do not
support it.") caused a build warning on some configurations:

drivers/base/topology.c: In function 'topology_is_visible':
drivers/base/topology.c:158:24: warning: unused variable 'dev' [-Wunused-variable]
  158 |         struct device *dev = kobj_to_dev(kobj);

Fix this up by getting rid of the variable entirely.

Fixes: aa63a74d4535 ("topology/sysfs: Hide PPIN on systems that do not support it.")
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Reported-by: Stephen Rothwell &lt;sfr@canb.auug.org.au&gt;
Link: https://lore.kernel.org/r/20220422062653.3899972-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arch_topology: Do not set llc_sibling if llc_id is invalid</title>
<updated>2022-04-20T16:57:59+00:00</updated>
<author>
<name>Wang Qing</name>
<email>wangqing@vivo.com</email>
</author>
<published>2022-04-11T02:36:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1dc9f1a66e1718479e1c4f95514e1750602a3cb9'/>
<id>1dc9f1a66e1718479e1c4f95514e1750602a3cb9</id>
<content type='text'>
When ACPI is not enabled, cpuid_topo-&gt;llc_id = cpu_topo-&gt;llc_id = -1, which
will set llc_sibling 0xff(...), this is misleading.

Don't set llc_sibling(default 0) if we don't know the cache topology.

Reviewed-by: Sudeep Holla &lt;sudeep.holla@arm.com&gt;
Signed-off-by: Wang Qing &lt;wangqing@vivo.com&gt;
Fixes: 37c3ec2d810f ("arm64: topology: divorce MC scheduling domain from core_siblings")
Cc: stable &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/1649644580-54626-1-git-send-email-wangqing@vivo.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>
When ACPI is not enabled, cpuid_topo-&gt;llc_id = cpu_topo-&gt;llc_id = -1, which
will set llc_sibling 0xff(...), this is misleading.

Don't set llc_sibling(default 0) if we don't know the cache topology.

Reviewed-by: Sudeep Holla &lt;sudeep.holla@arm.com&gt;
Signed-off-by: Wang Qing &lt;wangqing@vivo.com&gt;
Fixes: 37c3ec2d810f ("arm64: topology: divorce MC scheduling domain from core_siblings")
Cc: stable &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/1649644580-54626-1-git-send-email-wangqing@vivo.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>topology: make core_mask include at least cluster_siblings</title>
<updated>2022-04-20T16:57:20+00:00</updated>
<author>
<name>Darren Hart</name>
<email>darren@os.amperecomputing.com</email>
</author>
<published>2022-04-11T20:53:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=db1e59483dfd8d4e956575302520bb8f7e20c79b'/>
<id>db1e59483dfd8d4e956575302520bb8f7e20c79b</id>
<content type='text'>
Ampere Altra defines CPU clusters in the ACPI PPTT. They share a Snoop
Control Unit, but have no shared CPU-side last level cache.

cpu_coregroup_mask() will return a cpumask with weight 1, while
cpu_clustergroup_mask() will return a cpumask with weight 2.

As a result, build_sched_domain() will BUG() once per CPU with:

BUG: arch topology borken
the CLS domain not a subset of the MC domain

The MC level cpumask is then extended to that of the CLS child, and is
later removed entirely as redundant. This sched domain topology is an
improvement over previous topologies, or those built without
SCHED_CLUSTER, particularly for certain latency sensitive workloads.
With the current scheduler model and heuristics, this is a desirable
default topology for Ampere Altra and Altra Max system.

Rather than create a custom sched domains topology structure and
introduce new logic in arch/arm64 to detect these systems, update the
core_mask so coregroup is never a subset of clustergroup, extending it
to cluster_siblings if necessary. Only do this if CONFIG_SCHED_CLUSTER
is enabled to avoid also changing the topology (MC) when
CONFIG_SCHED_CLUSTER is disabled.

This has the added benefit over a custom topology of working for both
symmetric and asymmetric topologies. It does not address systems where
the CLUSTER topology is above a populated MC topology, but these are not
considered today and can be addressed separately if and when they
appear.

The final sched domain topology for a 2 socket Ampere Altra system is
unchanged with or without CONFIG_SCHED_CLUSTER, and the BUG is avoided:

For CPU0:

CONFIG_SCHED_CLUSTER=y
CLS  [0-1]
DIE  [0-79]
NUMA [0-159]

CONFIG_SCHED_CLUSTER is not set
DIE  [0-79]
NUMA [0-159]

Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: "Rafael J. Wysocki" &lt;rafael@kernel.org&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Vincent Guittot &lt;vincent.guittot@linaro.org&gt;
Cc: D. Scott Phillips &lt;scott@os.amperecomputing.com&gt;
Cc: Ilkka Koskinen &lt;ilkka@os.amperecomputing.com&gt;
Cc: &lt;stable@vger.kernel.org&gt; # 5.16.x
Suggested-by: Barry Song &lt;song.bao.hua@hisilicon.com&gt;
Reviewed-by: Barry Song &lt;song.bao.hua@hisilicon.com&gt;
Reviewed-by: Dietmar Eggemann &lt;dietmar.eggemann@arm.com&gt;
Acked-by: Sudeep Holla &lt;sudeep.holla@arm.com&gt;
Signed-off-by: Darren Hart &lt;darren@os.amperecomputing.com&gt;
Link: https://lore.kernel.org/r/c8fe9fce7c86ed56b4c455b8c902982dc2303868.1649696956.git.darren@os.amperecomputing.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>
Ampere Altra defines CPU clusters in the ACPI PPTT. They share a Snoop
Control Unit, but have no shared CPU-side last level cache.

cpu_coregroup_mask() will return a cpumask with weight 1, while
cpu_clustergroup_mask() will return a cpumask with weight 2.

As a result, build_sched_domain() will BUG() once per CPU with:

BUG: arch topology borken
the CLS domain not a subset of the MC domain

The MC level cpumask is then extended to that of the CLS child, and is
later removed entirely as redundant. This sched domain topology is an
improvement over previous topologies, or those built without
SCHED_CLUSTER, particularly for certain latency sensitive workloads.
With the current scheduler model and heuristics, this is a desirable
default topology for Ampere Altra and Altra Max system.

Rather than create a custom sched domains topology structure and
introduce new logic in arch/arm64 to detect these systems, update the
core_mask so coregroup is never a subset of clustergroup, extending it
to cluster_siblings if necessary. Only do this if CONFIG_SCHED_CLUSTER
is enabled to avoid also changing the topology (MC) when
CONFIG_SCHED_CLUSTER is disabled.

This has the added benefit over a custom topology of working for both
symmetric and asymmetric topologies. It does not address systems where
the CLUSTER topology is above a populated MC topology, but these are not
considered today and can be addressed separately if and when they
appear.

The final sched domain topology for a 2 socket Ampere Altra system is
unchanged with or without CONFIG_SCHED_CLUSTER, and the BUG is avoided:

For CPU0:

CONFIG_SCHED_CLUSTER=y
CLS  [0-1]
DIE  [0-79]
NUMA [0-159]

CONFIG_SCHED_CLUSTER is not set
DIE  [0-79]
NUMA [0-159]

Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: "Rafael J. Wysocki" &lt;rafael@kernel.org&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Vincent Guittot &lt;vincent.guittot@linaro.org&gt;
Cc: D. Scott Phillips &lt;scott@os.amperecomputing.com&gt;
Cc: Ilkka Koskinen &lt;ilkka@os.amperecomputing.com&gt;
Cc: &lt;stable@vger.kernel.org&gt; # 5.16.x
Suggested-by: Barry Song &lt;song.bao.hua@hisilicon.com&gt;
Reviewed-by: Barry Song &lt;song.bao.hua@hisilicon.com&gt;
Reviewed-by: Dietmar Eggemann &lt;dietmar.eggemann@arm.com&gt;
Acked-by: Sudeep Holla &lt;sudeep.holla@arm.com&gt;
Signed-off-by: Darren Hart &lt;darren@os.amperecomputing.com&gt;
Link: https://lore.kernel.org/r/c8fe9fce7c86ed56b4c455b8c902982dc2303868.1649696956.git.darren@os.amperecomputing.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>topology/sysfs: Hide PPIN on systems that do not support it.</title>
<updated>2022-04-20T16:56:39+00:00</updated>
<author>
<name>Tony Luck</name>
<email>tony.luck@intel.com</email>
</author>
<published>2022-04-06T22:01:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=aa63a74d4535a1d97b60e46655a1361c42565b89'/>
<id>aa63a74d4535a1d97b60e46655a1361c42565b89</id>
<content type='text'>
Systems that do not support a Protected Processor Identification Number
currently report:

	# cat /sys/devices/system/cpu/cpu0/topology/ppin
	0x0

which is confusing/wrong.

Add a ".is_visible" function to suppress inclusion of the ppin file.

Fixes: ab28e944197f ("topology/sysfs: Add PPIN in sysfs under cpu topology")
Signed-off-by: Tony Luck &lt;tony.luck@intel.com&gt;
Link: https://lore.kernel.org/r/20220406220150.63855-1-tony.luck@intel.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>
Systems that do not support a Protected Processor Identification Number
currently report:

	# cat /sys/devices/system/cpu/cpu0/topology/ppin
	0x0

which is confusing/wrong.

Add a ".is_visible" function to suppress inclusion of the ppin file.

Fixes: ab28e944197f ("topology/sysfs: Add PPIN in sysfs under cpu topology")
Signed-off-by: Tony Luck &lt;tony.luck@intel.com&gt;
Link: https://lore.kernel.org/r/20220406220150.63855-1-tony.luck@intel.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
