<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/drivers/acpi, branch v5.1-rc5</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>ACPICA: Namespace: remove address node from global list after method termination</title>
<updated>2019-04-09T08:05:11+00:00</updated>
<author>
<name>Erik Schmauss</name>
<email>erik.schmauss@intel.com</email>
</author>
<published>2019-04-08T20:42:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=c5781ffbbd4f742a58263458145fe7f0ac01d9e0'/>
<id>c5781ffbbd4f742a58263458145fe7f0ac01d9e0</id>
<content type='text'>
ACPICA commit b233720031a480abd438f2e9c643080929d144c3

ASL operation_regions declare a range of addresses that it uses. In a
perfect world, the range of addresses should be used exclusively by
the AML interpreter. The OS can use this information to decide which
drivers to load so that the AML interpreter and device drivers use
different regions of memory.

During table load, the address information is added to a global
address range list. Each node in this list contains an address range
as well as a namespace node of the operation_region. This list is
deleted at ACPI shutdown.

Unfortunately, ASL operation_regions can be declared inside of control
methods. Although this is not recommended, modern firmware contains
such code. New module level code changes unintentionally removed the
functionality of adding and removing nodes to the global address
range list.

A few months ago, support for adding addresses has been re-
implemented. However, the removal of the address range list was
missed and resulted in some systems to crash due to the address list
containing bogus namespace nodes from operation_regions declared in
control methods. In order to fix the crash, this change removes
dynamic operation_regions after control method termination.

Link: https://github.com/acpica/acpica/commit/b2337200
Link: https://bugzilla.kernel.org/show_bug.cgi?id=202475
Fixes: 4abb951b73ff ("ACPICA: AML interpreter: add region addresses in global list during initialization")
Reported-by: Michael J Gruber &lt;mjg@fedoraproject.org&gt;
Signed-off-by: Erik Schmauss &lt;erik.schmauss@intel.com&gt;
Signed-off-by: Bob Moore &lt;robert.moore@intel.com&gt;
Cc: 4.20+ &lt;stable@vger.kernel.org&gt; # 4.20+
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
ACPICA commit b233720031a480abd438f2e9c643080929d144c3

ASL operation_regions declare a range of addresses that it uses. In a
perfect world, the range of addresses should be used exclusively by
the AML interpreter. The OS can use this information to decide which
drivers to load so that the AML interpreter and device drivers use
different regions of memory.

During table load, the address information is added to a global
address range list. Each node in this list contains an address range
as well as a namespace node of the operation_region. This list is
deleted at ACPI shutdown.

Unfortunately, ASL operation_regions can be declared inside of control
methods. Although this is not recommended, modern firmware contains
such code. New module level code changes unintentionally removed the
functionality of adding and removing nodes to the global address
range list.

A few months ago, support for adding addresses has been re-
implemented. However, the removal of the address range list was
missed and resulted in some systems to crash due to the address list
containing bogus namespace nodes from operation_regions declared in
control methods. In order to fix the crash, this change removes
dynamic operation_regions after control method termination.

Link: https://github.com/acpica/acpica/commit/b2337200
Link: https://bugzilla.kernel.org/show_bug.cgi?id=202475
Fixes: 4abb951b73ff ("ACPICA: AML interpreter: add region addresses in global list during initialization")
Reported-by: Michael J Gruber &lt;mjg@fedoraproject.org&gt;
Signed-off-by: Erik Schmauss &lt;erik.schmauss@intel.com&gt;
Signed-off-by: Bob Moore &lt;robert.moore@intel.com&gt;
Cc: 4.20+ &lt;stable@vger.kernel.org&gt; # 4.20+
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'acpi-5.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm</title>
<updated>2019-04-05T00:48:11+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2019-04-05T00:48:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=b512f71221d0bcb07ab32f3e958a84e164c85881'/>
<id>b512f71221d0bcb07ab32f3e958a84e164c85881</id>
<content type='text'>
Pull ACPI fix from Rafael Wysocki:
 "Prevent stale GPE events from triggering spurious system wakeups from
  suspend-to-idle (Furquan Shaikh)"

* tag 'acpi-5.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPICA: Clear status of GPEs before enabling them
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull ACPI fix from Rafael Wysocki:
 "Prevent stale GPE events from triggering spurious system wakeups from
  suspend-to-idle (Furquan Shaikh)"

* tag 'acpi-5.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPICA: Clear status of GPEs before enabling them
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'acpica' into acpi</title>
<updated>2019-04-04T20:08:47+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rafael.j.wysocki@intel.com</email>
</author>
<published>2019-04-04T20:08:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=b59fb7ef5240c301ca8b5b70d4298c0f053bb0c3'/>
<id>b59fb7ef5240c301ca8b5b70d4298c0f053bb0c3</id>
<content type='text'>
* acpica:
  ACPICA: Clear status of GPEs before enabling them
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
* acpica:
  ACPICA: Clear status of GPEs before enabling them
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'acpi-5.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm</title>
<updated>2019-03-30T17:09:11+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2019-03-30T17:09:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=782492a7a4807317319a0b1832594d07ba79747d'/>
<id>782492a7a4807317319a0b1832594d07ba79747d</id>
<content type='text'>
Pull ACPI fix from Rafael Wysocki:
 "This corrects a previous attempt to make Linux use its own set of ACPI
  debug flags different from the upstream ACPICA's default (Erik
  Schmauss)"

* tag 'acpi-5.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI: use different default debug value than ACPICA
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull ACPI fix from Rafael Wysocki:
 "This corrects a previous attempt to make Linux use its own set of ACPI
  debug flags different from the upstream ACPICA's default (Erik
  Schmauss)"

* tag 'acpi-5.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI: use different default debug value than ACPICA
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPICA: Clear status of GPEs before enabling them</title>
<updated>2019-03-28T09:27:02+00:00</updated>
<author>
<name>Furquan Shaikh</name>
<email>furquan@google.com</email>
</author>
<published>2019-03-20T22:28:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=c8b1917c8987a6fa3695d479b4d60fbbbc3e537b'/>
<id>c8b1917c8987a6fa3695d479b4d60fbbbc3e537b</id>
<content type='text'>
Commit 18996f2db918 ("ACPICA: Events: Stop unconditionally clearing
ACPI IRQs during suspend/resume") was added to stop clearing event
status bits unconditionally in the system-wide suspend and resume
paths. This was done because of an issue with a laptop lid appaering
to be closed even when it was used to wake up the system from suspend
(see https://bugzilla.kernel.org/show_bug.cgi?id=196249), which
happened because event status bits were cleared unconditionally on
system resume. Though this change fixed the issue in the resume path,
it introduced regressions in a few suspend paths.

First regression was reported and fixed in the S5 entry path by commit
fa85015c0d95 ("ACPICA: Clear status of all events when entering S5").
Next regression was reported and fixed for all legacy sleep paths by
commit f317c7dc12b7 ("ACPICA: Clear status of all events when entering
sleep states").  However, there still is a suspend-to-idle regression,
since suspend-to-idle does not follow the legacy sleep paths.

In the suspend-to-idle case, wakeup is enabled as part of device
suspend.  If the status bits of wakeup GPEs are set when they are
enabled, it causes a premature system wakeup to occur.

To address that problem, partially revert commit 18996f2db918 to
restore GPE status bits clearing before the GPE is enabled in
acpi_ev_enable_gpe().

Fixes: 18996f2db918 ("ACPICA: Events: Stop unconditionally clearing ACPI IRQs during suspend/resume")
Signed-off-by: Furquan Shaikh &lt;furquan@google.com&gt;
Cc: 4.17+ &lt;stable@vger.kernel.org&gt; # 4.17+
[ rjw: Subject &amp; changelog ]
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit 18996f2db918 ("ACPICA: Events: Stop unconditionally clearing
ACPI IRQs during suspend/resume") was added to stop clearing event
status bits unconditionally in the system-wide suspend and resume
paths. This was done because of an issue with a laptop lid appaering
to be closed even when it was used to wake up the system from suspend
(see https://bugzilla.kernel.org/show_bug.cgi?id=196249), which
happened because event status bits were cleared unconditionally on
system resume. Though this change fixed the issue in the resume path,
it introduced regressions in a few suspend paths.

First regression was reported and fixed in the S5 entry path by commit
fa85015c0d95 ("ACPICA: Clear status of all events when entering S5").
Next regression was reported and fixed for all legacy sleep paths by
commit f317c7dc12b7 ("ACPICA: Clear status of all events when entering
sleep states").  However, there still is a suspend-to-idle regression,
since suspend-to-idle does not follow the legacy sleep paths.

In the suspend-to-idle case, wakeup is enabled as part of device
suspend.  If the status bits of wakeup GPEs are set when they are
enabled, it causes a premature system wakeup to occur.

To address that problem, partially revert commit 18996f2db918 to
restore GPE status bits clearing before the GPE is enabled in
acpi_ev_enable_gpe().

Fixes: 18996f2db918 ("ACPICA: Events: Stop unconditionally clearing ACPI IRQs during suspend/resume")
Signed-off-by: Furquan Shaikh &lt;furquan@google.com&gt;
Cc: 4.17+ &lt;stable@vger.kernel.org&gt; # 4.17+
[ rjw: Subject &amp; changelog ]
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI / CPPC: Fix guaranteed performance handling</title>
<updated>2019-03-25T22:57:21+00:00</updated>
<author>
<name>Srinivas Pandruvada</name>
<email>srinivas.pandruvada@linux.intel.com</email>
</author>
<published>2019-03-25T16:04:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=edef1ef134180149694b86386277076f566d165c'/>
<id>edef1ef134180149694b86386277076f566d165c</id>
<content type='text'>
As per the ACPI specification, "Guaranteed Performance Register" is
a "Buffer" field and it cannot be "Integer", so treat the "Integer"
type for "Guaranteed Performance Register" field as invalid and
ignore its value in that case.

Also save one cpc_read() call when "Guaranteed Performance Register"
is not present, which means a register defined as:
"Register(SystemMemory, 0, 0, 0, 0)".

Fixes: 29523f095397 ("ACPI / CPPC: Add support for guaranteed performance")
Suggested-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
Cc: 4.20+ &lt;stable@vger.kernel.org&gt; # 4.20+
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
As per the ACPI specification, "Guaranteed Performance Register" is
a "Buffer" field and it cannot be "Integer", so treat the "Integer"
type for "Guaranteed Performance Register" field as invalid and
ignore its value in that case.

Also save one cpc_read() call when "Guaranteed Performance Register"
is not present, which means a register defined as:
"Register(SystemMemory, 0, 0, 0, 0)".

Fixes: 29523f095397 ("ACPI / CPPC: Add support for guaranteed performance")
Suggested-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
Cc: 4.20+ &lt;stable@vger.kernel.org&gt; # 4.20+
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI: use different default debug value than ACPICA</title>
<updated>2019-03-25T09:45:59+00:00</updated>
<author>
<name>Erik Schmauss</name>
<email>erik.schmauss@intel.com</email>
</author>
<published>2019-03-22T01:20:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=aa9aaa4d61c0048d3faad056893cd7860bbc084c'/>
<id>aa9aaa4d61c0048d3faad056893cd7860bbc084c</id>
<content type='text'>
Rather than setting debug output flags during early init, its makes
more sense to simply re-define ACPI_DEBUG_DEFAULT specifically for
Linux.

ACPICA commit 60903715711f4b00ca1831779a8a23279a66497d

Link: https://github.com/acpica/acpica/commit/60903715
Fixes: ce5cbf53496b ("ACPI: Set debug output flags independent of ACPICA")
Reported-by: Alexandru Gagniuc &lt;mr.nuke.me@gmail.com&gt;
Tested-by: Alexandru Gagniuc &lt;mr.nuke.me@gmail.com&gt;
Signed-off-by: Erik Schmauss &lt;erik.schmauss@intel.com&gt;
Signed-off-by: Bob Moore &lt;robert.moore@intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Rather than setting debug output flags during early init, its makes
more sense to simply re-define ACPI_DEBUG_DEFAULT specifically for
Linux.

ACPICA commit 60903715711f4b00ca1831779a8a23279a66497d

Link: https://github.com/acpica/acpica/commit/60903715
Fixes: ce5cbf53496b ("ACPI: Set debug output flags independent of ACPICA")
Reported-by: Alexandru Gagniuc &lt;mr.nuke.me@gmail.com&gt;
Tested-by: Alexandru Gagniuc &lt;mr.nuke.me@gmail.com&gt;
Signed-off-by: Erik Schmauss &lt;erik.schmauss@intel.com&gt;
Signed-off-by: Bob Moore &lt;robert.moore@intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI / utils: Drop reference in test for device presence</title>
<updated>2019-03-19T21:34:21+00:00</updated>
<author>
<name>Andy Shevchenko</name>
<email>andriy.shevchenko@linux.intel.com</email>
</author>
<published>2019-03-18T18:47:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=54e3aca84e571559915998aa6cc05e5ac37c043b'/>
<id>54e3aca84e571559915998aa6cc05e5ac37c043b</id>
<content type='text'>
When commit 8661423eea1a ("ACPI / utils: Add new acpi_dev_present
helper") introduced acpi_dev_present(), it missed the fact that
bus_find_device() took a reference on the device found by it and
the callers of acpi_dev_present() don't drop that reference.

Drop the reference on the device in acpi_dev_present().

Fixes: 8661423eea1a ("ACPI / utils: Add new acpi_dev_present helper")
Signed-off-by: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Reviewed-by: Hans de Goede &lt;hdegoede@redhat.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When commit 8661423eea1a ("ACPI / utils: Add new acpi_dev_present
helper") introduced acpi_dev_present(), it missed the fact that
bus_find_device() took a reference on the device found by it and
the callers of acpi_dev_present() don't drop that reference.

Drop the reference on the device in acpi_dev_present().

Fixes: 8661423eea1a ("ACPI / utils: Add new acpi_dev_present helper")
Signed-off-by: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Reviewed-by: Hans de Goede &lt;hdegoede@redhat.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'devdax-for-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm</title>
<updated>2019-03-16T20:05:32+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2019-03-16T20:05:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f67e3fb4891287b8248ebb3320f794b9f5e782d4'/>
<id>f67e3fb4891287b8248ebb3320f794b9f5e782d4</id>
<content type='text'>
Pull device-dax updates from Dan Williams:
 "New device-dax infrastructure to allow persistent memory and other
  "reserved" / performance differentiated memories, to be assigned to
  the core-mm as "System RAM".

  Some users want to use persistent memory as additional volatile
  memory. They are willing to cope with potential performance
  differences, for example between DRAM and 3D Xpoint, and want to use
  typical Linux memory management apis rather than a userspace memory
  allocator layered over an mmap() of a dax file. The administration
  model is to decide how much Persistent Memory (pmem) to use as System
  RAM, create a device-dax-mode namespace of that size, and then assign
  it to the core-mm. The rationale for device-dax is that it is a
  generic memory-mapping driver that can be layered over any "special
  purpose" memory, not just pmem. On subsequent boots udev rules can be
  used to restore the memory assignment.

  One implication of using pmem as RAM is that mlock() no longer keeps
  data off persistent media. For this reason it is recommended to enable
  NVDIMM Security (previously merged for 5.0) to encrypt pmem contents
  at rest. We considered making this recommendation an actively enforced
  requirement, but in the end decided to leave it as a distribution /
  administrator policy to allow for emulation and test environments that
  lack security capable NVDIMMs.

  Summary:

   - Replace the /sys/class/dax device model with /sys/bus/dax, and
     include a compat driver so distributions can opt-in to the new ABI.

   - Allow for an alternative driver for the device-dax address-range

   - Introduce the 'kmem' driver to hotplug / assign a device-dax
     address-range to the core-mm.

   - Arrange for the device-dax target-node to be onlined so that the
     newly added memory range can be uniquely referenced by numa apis"

NOTE! I'm not entirely happy with the whole "PMEM as RAM" model because
we currently have special - and very annoying rules in the kernel about
accessing PMEM only with the "MC safe" accessors, because machine checks
inside the regular repeat string copy functions can be fatal in some
(not described) circumstances.

And apparently the PMEM modules can cause that a lot more than regular
RAM.  The argument is that this happens because PMEM doesn't necessarily
get scrubbed at boot like RAM does, but that is planned to be added for
the user space tooling.

Quoting Dan from another email:
 "The exposure can be reduced in the volatile-RAM case by scanning for
  and clearing errors before it is onlined as RAM. The userspace tooling
  for that can be in place before v5.1-final. There's also runtime
  notifications of errors via acpi_nfit_uc_error_notify() from
  background scrubbers on the DIMM devices. With that mechanism the
  kernel could proactively clear newly discovered poison in the volatile
  case, but that would be additional development more suitable for v5.2.

  I understand the concern, and the need to highlight this issue by
  tapping the brakes on feature development, but I don't see PMEM as RAM
  making the situation worse when the exposure is also there via DAX in
  the PMEM case. Volatile-RAM is arguably a safer use case since it's
  possible to repair pages where the persistent case needs active
  application coordination"

* tag 'devdax-for-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  device-dax: "Hotplug" persistent memory for use like normal RAM
  mm/resource: Let walk_system_ram_range() search child resources
  mm/memory-hotplug: Allow memory resources to be children
  mm/resource: Move HMM pr_debug() deeper into resource code
  mm/resource: Return real error codes from walk failures
  device-dax: Add a 'modalias' attribute to DAX 'bus' devices
  device-dax: Add a 'target_node' attribute
  device-dax: Auto-bind device after successful new_id
  acpi/nfit, device-dax: Identify differentiated memory with a unique numa-node
  device-dax: Add /sys/class/dax backwards compatibility
  device-dax: Add support for a dax override driver
  device-dax: Move resource pinning+mapping into the common driver
  device-dax: Introduce bus + driver model
  device-dax: Start defining a dax bus model
  device-dax: Remove multi-resource infrastructure
  device-dax: Kill dax_region base
  device-dax: Kill dax_region ida
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull device-dax updates from Dan Williams:
 "New device-dax infrastructure to allow persistent memory and other
  "reserved" / performance differentiated memories, to be assigned to
  the core-mm as "System RAM".

  Some users want to use persistent memory as additional volatile
  memory. They are willing to cope with potential performance
  differences, for example between DRAM and 3D Xpoint, and want to use
  typical Linux memory management apis rather than a userspace memory
  allocator layered over an mmap() of a dax file. The administration
  model is to decide how much Persistent Memory (pmem) to use as System
  RAM, create a device-dax-mode namespace of that size, and then assign
  it to the core-mm. The rationale for device-dax is that it is a
  generic memory-mapping driver that can be layered over any "special
  purpose" memory, not just pmem. On subsequent boots udev rules can be
  used to restore the memory assignment.

  One implication of using pmem as RAM is that mlock() no longer keeps
  data off persistent media. For this reason it is recommended to enable
  NVDIMM Security (previously merged for 5.0) to encrypt pmem contents
  at rest. We considered making this recommendation an actively enforced
  requirement, but in the end decided to leave it as a distribution /
  administrator policy to allow for emulation and test environments that
  lack security capable NVDIMMs.

  Summary:

   - Replace the /sys/class/dax device model with /sys/bus/dax, and
     include a compat driver so distributions can opt-in to the new ABI.

   - Allow for an alternative driver for the device-dax address-range

   - Introduce the 'kmem' driver to hotplug / assign a device-dax
     address-range to the core-mm.

   - Arrange for the device-dax target-node to be onlined so that the
     newly added memory range can be uniquely referenced by numa apis"

NOTE! I'm not entirely happy with the whole "PMEM as RAM" model because
we currently have special - and very annoying rules in the kernel about
accessing PMEM only with the "MC safe" accessors, because machine checks
inside the regular repeat string copy functions can be fatal in some
(not described) circumstances.

And apparently the PMEM modules can cause that a lot more than regular
RAM.  The argument is that this happens because PMEM doesn't necessarily
get scrubbed at boot like RAM does, but that is planned to be added for
the user space tooling.

Quoting Dan from another email:
 "The exposure can be reduced in the volatile-RAM case by scanning for
  and clearing errors before it is onlined as RAM. The userspace tooling
  for that can be in place before v5.1-final. There's also runtime
  notifications of errors via acpi_nfit_uc_error_notify() from
  background scrubbers on the DIMM devices. With that mechanism the
  kernel could proactively clear newly discovered poison in the volatile
  case, but that would be additional development more suitable for v5.2.

  I understand the concern, and the need to highlight this issue by
  tapping the brakes on feature development, but I don't see PMEM as RAM
  making the situation worse when the exposure is also there via DAX in
  the PMEM case. Volatile-RAM is arguably a safer use case since it's
  possible to repair pages where the persistent case needs active
  application coordination"

* tag 'devdax-for-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  device-dax: "Hotplug" persistent memory for use like normal RAM
  mm/resource: Let walk_system_ram_range() search child resources
  mm/memory-hotplug: Allow memory resources to be children
  mm/resource: Move HMM pr_debug() deeper into resource code
  mm/resource: Return real error codes from walk failures
  device-dax: Add a 'modalias' attribute to DAX 'bus' devices
  device-dax: Add a 'target_node' attribute
  device-dax: Auto-bind device after successful new_id
  acpi/nfit, device-dax: Identify differentiated memory with a unique numa-node
  device-dax: Add /sys/class/dax backwards compatibility
  device-dax: Add support for a dax override driver
  device-dax: Move resource pinning+mapping into the common driver
  device-dax: Introduce bus + driver model
  device-dax: Start defining a dax bus model
  device-dax: Remove multi-resource infrastructure
  device-dax: Kill dax_region base
  device-dax: Kill dax_region ida
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'acpi-5.1-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm</title>
<updated>2019-03-14T17:48:14+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2019-03-14T17:48:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=3b319ee220a8795406852a897299dbdfc1b09911'/>
<id>3b319ee220a8795406852a897299dbdfc1b09911</id>
<content type='text'>
Pull more ACPI updates from Rafael Wysocki:
 "These fix a couple of issues and do some cleanups on top of the
  previous ACPI changes for 5.1-rc1.

  Specifics:

   - Fix a crash caused by unloading an SSDT overlay (Andy Shevchenko)

   - Prevent user space from getting confusing error values on failing
     ACPI sysfs accesses (Rafael Wysocki)

   - Simplify leaf node detection in the PPTT parsing code by using a
     new flag defined in ACPI 6.3 (Jeremy Linton)

   - Add missing "static" in some places in the ACPI configfs code (Andy
     Shevchenko)

   - Fix acpidbg tool path in the ACPI documentation (Flavio Suligoi)"

* tag 'acpi-5.1-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI: sysfs: Prevent get_status() from returning acpi_status
  ACPI / device_sysfs: Avoid OF modalias creation for removed device
  ACPI / configfs: Mark local data structures static
  ACPI / configfs: Mark local functions static
  ACPI: tables: Simplify PPTT leaf node detection
  ACPI: Documentation: Fix path for acpidbg tool
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull more ACPI updates from Rafael Wysocki:
 "These fix a couple of issues and do some cleanups on top of the
  previous ACPI changes for 5.1-rc1.

  Specifics:

   - Fix a crash caused by unloading an SSDT overlay (Andy Shevchenko)

   - Prevent user space from getting confusing error values on failing
     ACPI sysfs accesses (Rafael Wysocki)

   - Simplify leaf node detection in the PPTT parsing code by using a
     new flag defined in ACPI 6.3 (Jeremy Linton)

   - Add missing "static" in some places in the ACPI configfs code (Andy
     Shevchenko)

   - Fix acpidbg tool path in the ACPI documentation (Flavio Suligoi)"

* tag 'acpi-5.1-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI: sysfs: Prevent get_status() from returning acpi_status
  ACPI / device_sysfs: Avoid OF modalias creation for removed device
  ACPI / configfs: Mark local data structures static
  ACPI / configfs: Mark local functions static
  ACPI: tables: Simplify PPTT leaf node detection
  ACPI: Documentation: Fix path for acpidbg tool
</pre>
</div>
</content>
</entry>
</feed>
