<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/drivers/acpi/processor_idle.c, branch v5.13</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge branches 'acpi-pci' and 'acpi-processor'</title>
<updated>2021-04-26T15:03:05+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rafael.j.wysocki@intel.com</email>
</author>
<published>2021-04-26T15:03:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=25d95763269135b995a10f7ff9662aae66094258'/>
<id>25d95763269135b995a10f7ff9662aae66094258</id>
<content type='text'>
* acpi-pci:
  ACPI: PCI: Replace direct printk() invocations in pci_link.c
  ACPI: PCI: Drop ACPI_PCI_COMPONENT that is not used any more
  ACPI: PCI: Replace ACPI_DEBUG_PRINT() and ACPI_EXCEPTION()
  ACPI: PCI: IRQ: Consolidate printing diagnostic messages

* acpi-processor:
  ACPI: processor: perflib: Eliminate redundant status check
  ACPI: processor: Get rid of ACPICA message printing
  ACPI: processor: idle: Drop extra prefix from pr_notice()
  ACPI: processor: Remove initialization of static variable
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
* acpi-pci:
  ACPI: PCI: Replace direct printk() invocations in pci_link.c
  ACPI: PCI: Drop ACPI_PCI_COMPONENT that is not used any more
  ACPI: PCI: Replace ACPI_DEBUG_PRINT() and ACPI_EXCEPTION()
  ACPI: PCI: IRQ: Consolidate printing diagnostic messages

* acpi-processor:
  ACPI: processor: perflib: Eliminate redundant status check
  ACPI: processor: Get rid of ACPICA message printing
  ACPI: processor: idle: Drop extra prefix from pr_notice()
  ACPI: processor: Remove initialization of static variable
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI: processor: Fix build when CONFIG_ACPI_PROCESSOR=m</title>
<updated>2021-04-07T17:02:43+00:00</updated>
<author>
<name>Vitaly Kuznetsov</name>
<email>vkuznets@redhat.com</email>
</author>
<published>2021-04-06T15:56:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=fa26d0c778b432d3d9814ea82552e813b33eeb5c'/>
<id>fa26d0c778b432d3d9814ea82552e813b33eeb5c</id>
<content type='text'>
Commit 8cdddd182bd7 ("ACPI: processor: Fix CPU0 wakeup in
acpi_idle_play_dead()") tried to fix CPU0 hotplug breakage by copying
wakeup_cpu0() + start_cpu0() logic from hlt_play_dead()//mwait_play_dead()
into acpi_idle_play_dead(). The problem is that these functions are not
exported to modules so when CONFIG_ACPI_PROCESSOR=m build fails.

The issue could've been fixed by exporting both wakeup_cpu0()/start_cpu0()
(the later from assembly) but it seems putting the whole pattern into a
new function and exporting it instead is better.

Reported-by: kernel test robot &lt;lkp@intel.com&gt;
Fixes: 8cdddd182bd7 ("CPI: processor: Fix CPU0 wakeup in acpi_idle_play_dead()")
Cc: &lt;stable@vger.kernel.org&gt; # 5.10+
Signed-off-by: Vitaly Kuznetsov &lt;vkuznets@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>
Commit 8cdddd182bd7 ("ACPI: processor: Fix CPU0 wakeup in
acpi_idle_play_dead()") tried to fix CPU0 hotplug breakage by copying
wakeup_cpu0() + start_cpu0() logic from hlt_play_dead()//mwait_play_dead()
into acpi_idle_play_dead(). The problem is that these functions are not
exported to modules so when CONFIG_ACPI_PROCESSOR=m build fails.

The issue could've been fixed by exporting both wakeup_cpu0()/start_cpu0()
(the later from assembly) but it seems putting the whole pattern into a
new function and exporting it instead is better.

Reported-by: kernel test robot &lt;lkp@intel.com&gt;
Fixes: 8cdddd182bd7 ("CPI: processor: Fix CPU0 wakeup in acpi_idle_play_dead()")
Cc: &lt;stable@vger.kernel.org&gt; # 5.10+
Signed-off-by: Vitaly Kuznetsov &lt;vkuznets@redhat.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge back 'acpi-processor' material for v5.13.</title>
<updated>2021-04-06T13:00:13+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rafael.j.wysocki@intel.com</email>
</author>
<published>2021-04-06T13:00:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=1c29f6a0f0c6ed44863046b8a51c40d4df804dd9'/>
<id>1c29f6a0f0c6ed44863046b8a51c40d4df804dd9</id>
<content type='text'>
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI: processor: Fix CPU0 wakeup in acpi_idle_play_dead()</title>
<updated>2021-04-01T11:37:55+00:00</updated>
<author>
<name>Vitaly Kuznetsov</name>
<email>vkuznets@redhat.com</email>
</author>
<published>2021-03-24T15:22:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=8cdddd182bd7befae6af49c5fd612893f55d6ccb'/>
<id>8cdddd182bd7befae6af49c5fd612893f55d6ccb</id>
<content type='text'>
Commit 496121c02127 ("ACPI: processor: idle: Allow probing on platforms
with one ACPI C-state") broke CPU0 hotplug on certain systems, e.g.
I'm observing the following on AWS Nitro (e.g r5b.xlarge but other
instance types are affected as well):

 # echo 0 &gt; /sys/devices/system/cpu/cpu0/online
 # echo 1 &gt; /sys/devices/system/cpu/cpu0/online
 &lt;10 seconds delay&gt;
 -bash: echo: write error: Input/output error

In fact, the above mentioned commit only revealed the problem and did
not introduce it. On x86, to wakeup CPU an NMI is being used and
hlt_play_dead()/mwait_play_dead() loops are prepared to handle it:

	/*
	 * If NMI wants to wake up CPU0, start CPU0.
	 */
	if (wakeup_cpu0())
		start_cpu0();

cpuidle_play_dead() -&gt; acpi_idle_play_dead() (which is now being called on
systems where it wasn't called before the above mentioned commit) serves
the same purpose but it doesn't have a path for CPU0. What happens now on
wakeup is:
 - NMI is sent to CPU0
 - wakeup_cpu0_nmi() works as expected
 - we get back to while (1) loop in acpi_idle_play_dead()
 - safe_halt() puts CPU0 to sleep again.

The straightforward/minimal fix is add the special handling for CPU0 on x86
and that's what the patch is doing.

Fixes: 496121c02127 ("ACPI: processor: idle: Allow probing on platforms with one ACPI C-state")
Signed-off-by: Vitaly Kuznetsov &lt;vkuznets@redhat.com&gt;
Cc: 5.10+ &lt;stable@vger.kernel.org&gt; # 5.10+
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 496121c02127 ("ACPI: processor: idle: Allow probing on platforms
with one ACPI C-state") broke CPU0 hotplug on certain systems, e.g.
I'm observing the following on AWS Nitro (e.g r5b.xlarge but other
instance types are affected as well):

 # echo 0 &gt; /sys/devices/system/cpu/cpu0/online
 # echo 1 &gt; /sys/devices/system/cpu/cpu0/online
 &lt;10 seconds delay&gt;
 -bash: echo: write error: Input/output error

In fact, the above mentioned commit only revealed the problem and did
not introduce it. On x86, to wakeup CPU an NMI is being used and
hlt_play_dead()/mwait_play_dead() loops are prepared to handle it:

	/*
	 * If NMI wants to wake up CPU0, start CPU0.
	 */
	if (wakeup_cpu0())
		start_cpu0();

cpuidle_play_dead() -&gt; acpi_idle_play_dead() (which is now being called on
systems where it wasn't called before the above mentioned commit) serves
the same purpose but it doesn't have a path for CPU0. What happens now on
wakeup is:
 - NMI is sent to CPU0
 - wakeup_cpu0_nmi() works as expected
 - we get back to while (1) loop in acpi_idle_play_dead()
 - safe_halt() puts CPU0 to sleep again.

The straightforward/minimal fix is add the special handling for CPU0 on x86
and that's what the patch is doing.

Fixes: 496121c02127 ("ACPI: processor: idle: Allow probing on platforms with one ACPI C-state")
Signed-off-by: Vitaly Kuznetsov &lt;vkuznets@redhat.com&gt;
Cc: 5.10+ &lt;stable@vger.kernel.org&gt; # 5.10+
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI: processor: Get rid of ACPICA message printing</title>
<updated>2021-03-08T15:51:19+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rafael.j.wysocki@intel.com</email>
</author>
<published>2021-02-22T18:59:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=52af99c3f55ff0afd815eac0271db2e1751af55c'/>
<id>52af99c3f55ff0afd815eac0271db2e1751af55c</id>
<content type='text'>
The ACPI_DEBUG_PRINT() and ACPI_EXCEPTION() macros are used for
message printing in the ACPICA code and they should not be used
elsewhere.  Special configuration (either kernel command line or
sysfs-based) is needed to see the messages printed by them and
the format of those messages is also special and convoluted.

For this reason, replace all of the ACPI_DEBUG_PRINT() and
ACPI_EXCEPTION() instances in the ACPI processor driver with
corresponding dev_*(), acpi_handle_*() and pr_*() calls depending
on the context in which they appear.

Also drop the ACPI_PROCESSOR_COMPONENT definition that is not going
to be necessary any more.

Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Reviewed-by: Hanjun Guo &lt;guohanjun@huawei.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The ACPI_DEBUG_PRINT() and ACPI_EXCEPTION() macros are used for
message printing in the ACPICA code and they should not be used
elsewhere.  Special configuration (either kernel command line or
sysfs-based) is needed to see the messages printed by them and
the format of those messages is also special and convoluted.

For this reason, replace all of the ACPI_DEBUG_PRINT() and
ACPI_EXCEPTION() instances in the ACPI processor driver with
corresponding dev_*(), acpi_handle_*() and pr_*() calls depending
on the context in which they appear.

Also drop the ACPI_PROCESSOR_COMPONENT definition that is not going
to be necessary any more.

Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Reviewed-by: Hanjun Guo &lt;guohanjun@huawei.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI: processor: idle: Drop extra prefix from pr_notice()</title>
<updated>2021-03-08T15:51:19+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rafael.j.wysocki@intel.com</email>
</author>
<published>2021-02-24T18:37:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=54e051920726caacc39b331647cdada93ee880da'/>
<id>54e051920726caacc39b331647cdada93ee880da</id>
<content type='text'>
Drop "ACPI: " from the pr_noitice() instance in
acpi_processor_cstate_first_run_checks(), because pr_fmt() causes
that prefix to be added to the message already.

Reported-by: Hanjun Guo &lt;guohanjun@huawei.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Reviewed-by: Hanjun Guo &lt;guohanjun@huawei.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Drop "ACPI: " from the pr_noitice() instance in
acpi_processor_cstate_first_run_checks(), because pr_fmt() causes
that prefix to be added to the message already.

Reported-by: Hanjun Guo &lt;guohanjun@huawei.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Reviewed-by: Hanjun Guo &lt;guohanjun@huawei.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI: processor: Remove the duplicated ACPI_PROCESSOR_CLASS macro</title>
<updated>2020-11-17T17:12:34+00:00</updated>
<author>
<name>Hanjun Guo</name>
<email>guohanjun@huawei.com</email>
</author>
<published>2020-11-13T02:08:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=eb37ba316fdec9c6af36b8b155732568c5b2a2d4'/>
<id>eb37ba316fdec9c6af36b8b155732568c5b2a2d4</id>
<content type='text'>
The ACPI_PROCESSOR_CLASS macro is defined in &lt;acpi/processor.h&gt;,
and ACPI drivers for processor already included &lt;acpi/processor.h&gt;,
so we can remove those duplicated ACPI_PROCESSOR_CLASS macros.

Signed-off-by: Hanjun Guo &lt;guohanjun@huawei.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>
The ACPI_PROCESSOR_CLASS macro is defined in &lt;acpi/processor.h&gt;,
and ACPI drivers for processor already included &lt;acpi/processor.h&gt;,
so we can remove those duplicated ACPI_PROCESSOR_CLASS macros.

Signed-off-by: Hanjun Guo &lt;guohanjun@huawei.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI: processor: Fix build for ARCH_APICTIMER_STOPS_ON_C3 unset</title>
<updated>2020-09-23T11:50:12+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rafael.j.wysocki@intel.com</email>
</author>
<published>2020-09-23T11:50:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=955921289dcdbc49b46a731ec07978fb7d4e1fc7'/>
<id>955921289dcdbc49b46a731ec07978fb7d4e1fc7</id>
<content type='text'>
Fix the lapic_timer_needs_broadcast() stub for
ARCH_APICTIMER_STOPS_ON_C3 unset to actually return
a value.

Fixes: aa6b43d57f99 ("ACPI: processor: Use CPUIDLE_FLAG_TIMER_STOP")
Reported-by: Guenter Roeck &lt;linux@roeck-us.net&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>
Fix the lapic_timer_needs_broadcast() stub for
ARCH_APICTIMER_STOPS_ON_C3 unset to actually return
a value.

Fixes: aa6b43d57f99 ("ACPI: processor: Use CPUIDLE_FLAG_TIMER_STOP")
Reported-by: Guenter Roeck &lt;linux@roeck-us.net&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI: processor: Take over RCU-idle for C3-BM idle</title>
<updated>2020-09-16T17:36:26+00:00</updated>
<author>
<name>Peter Zijlstra</name>
<email>peterz@infradead.org</email>
</author>
<published>2020-09-15T10:32:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=1fecfdbb7acc6624655450a609221c89b5197a06'/>
<id>1fecfdbb7acc6624655450a609221c89b5197a06</id>
<content type='text'>
The C3 BusMaster idle code takes lock in a number of places, some deep
inside the ACPI code. Instead of wrapping it all in RCU_NONIDLE, have
the driver take over RCU-idle duty and avoid flipping RCU state back
and forth a lot.

( by marking 'C3 &amp;&amp; bm_check' as RCU_IDLE, we _must_ call enter_bm() for
  that combination, otherwise we'll loose RCU-idle, this requires
  shuffling some code around )

Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Tested-by: Borislav Petkov &lt;bp@suse.de&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>
The C3 BusMaster idle code takes lock in a number of places, some deep
inside the ACPI code. Instead of wrapping it all in RCU_NONIDLE, have
the driver take over RCU-idle duty and avoid flipping RCU state back
and forth a lot.

( by marking 'C3 &amp;&amp; bm_check' as RCU_IDLE, we _must_ call enter_bm() for
  that combination, otherwise we'll loose RCU-idle, this requires
  shuffling some code around )

Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Tested-by: Borislav Petkov &lt;bp@suse.de&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI: processor: Use CPUIDLE_FLAG_TLB_FLUSHED</title>
<updated>2020-09-16T17:36:25+00:00</updated>
<author>
<name>Peter Zijlstra</name>
<email>peterz@infradead.org</email>
</author>
<published>2020-09-15T10:31:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=a889a23a98fee183c9b6b0b14b2fd70583429c5e'/>
<id>a889a23a98fee183c9b6b0b14b2fd70583429c5e</id>
<content type='text'>
Make acpi_processor_idle() use the generic TLB flushing code.
This again removes RCU usage after rcu_idle_enter().

(XXX make every C3 invalidate TLBs, not just C3-BM)

Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Tested-by: Borislav Petkov &lt;bp@suse.de&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>
Make acpi_processor_idle() use the generic TLB flushing code.
This again removes RCU usage after rcu_idle_enter().

(XXX make every C3 invalidate TLBs, not just C3-BM)

Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Tested-by: Borislav Petkov &lt;bp@suse.de&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
</feed>
