<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/arch/arm/kernel/process.c, branch v2.6.27.3</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>[ARM] Move include/asm-arm/arch-* to arch/arm/*/include/mach</title>
<updated>2008-08-07T08:55:48+00:00</updated>
<author>
<name>Russell King</name>
<email>rmk@dyn-67.arm.linux.org.uk</email>
</author>
<published>2008-08-05T15:14:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=a09e64fbc0094e3073dbb09c3b4bfe4ab669244b'/>
<id>a09e64fbc0094e3073dbb09c3b4bfe4ab669244b</id>
<content type='text'>
This just leaves include/asm-arm/plat-* to deal with.

Signed-off-by: Russell King &lt;rmk+kernel@arm.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This just leaves include/asm-arm/plat-* to deal with.

Signed-off-by: Russell King &lt;rmk+kernel@arm.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'linus' into timers/nohz</title>
<updated>2008-07-18T17:53:16+00:00</updated>
<author>
<name>Ingo Molnar</name>
<email>mingo@elte.hu</email>
</author>
<published>2008-07-18T17:53:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=9b610fda0df5d0f0b0c64242e37441ad1b384aac'/>
<id>9b610fda0df5d0f0b0c64242e37441ad1b384aac</id>
<content type='text'>
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
</pre>
</div>
</content>
</entry>
<entry>
<title>nohz: prevent tick stop outside of the idle loop</title>
<updated>2008-07-18T16:10:28+00:00</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2008-07-18T15:27:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=b8f8c3cf0a4ac0632ec3f0e15e9dc0c29de917af'/>
<id>b8f8c3cf0a4ac0632ec3f0e15e9dc0c29de917af</id>
<content type='text'>
Jack Ren and Eric Miao tracked down the following long standing
problem in the NOHZ code:

	scheduler switch to idle task
	enable interrupts

Window starts here

	----&gt; interrupt happens (does not set NEED_RESCHED)
	      	irq_exit() stops the tick

	----&gt; interrupt happens (does set NEED_RESCHED)

	return from schedule()
	
	cpu_idle(): preempt_disable();

Window ends here

The interrupts can happen at any point inside the race window. The
first interrupt stops the tick, the second one causes the scheduler to
rerun and switch away from idle again and we end up with the tick
disabled.

The fact that it needs two interrupts where the first one does not set
NEED_RESCHED and the second one does made the bug obscure and extremly
hard to reproduce and analyse. Kudos to Jack and Eric.

Solution: Limit the NOHZ functionality to the idle loop to make sure
that we can not run into such a situation ever again.

cpu_idle()
{
	preempt_disable();

	while(1) {
		 tick_nohz_stop_sched_tick(1); &lt;- tell NOHZ code that we
		 			          are in the idle loop

		 while (!need_resched())
		       halt();

		 tick_nohz_restart_sched_tick(); &lt;- disables NOHZ mode
		 preempt_enable_no_resched();
		 schedule();
		 preempt_disable();
	}
}

In hindsight we should have done this forever, but ... 

/me grabs a large brown paperbag.

Debugged-by: Jack Ren &lt;jack.ren@marvell.com&gt;, 
Debugged-by: eric miao &lt;eric.y.miao@gmail.com&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Jack Ren and Eric Miao tracked down the following long standing
problem in the NOHZ code:

	scheduler switch to idle task
	enable interrupts

Window starts here

	----&gt; interrupt happens (does not set NEED_RESCHED)
	      	irq_exit() stops the tick

	----&gt; interrupt happens (does set NEED_RESCHED)

	return from schedule()
	
	cpu_idle(): preempt_disable();

Window ends here

The interrupts can happen at any point inside the race window. The
first interrupt stops the tick, the second one causes the scheduler to
rerun and switch away from idle again and we end up with the tick
disabled.

The fact that it needs two interrupts where the first one does not set
NEED_RESCHED and the second one does made the bug obscure and extremly
hard to reproduce and analyse. Kudos to Jack and Eric.

Solution: Limit the NOHZ functionality to the idle loop to make sure
that we can not run into such a situation ever again.

cpu_idle()
{
	preempt_disable();

	while(1) {
		 tick_nohz_stop_sched_tick(1); &lt;- tell NOHZ code that we
		 			          are in the idle loop

		 while (!need_resched())
		       halt();

		 tick_nohz_restart_sched_tick(); &lt;- disables NOHZ mode
		 preempt_enable_no_resched();
		 schedule();
		 preempt_disable();
	}
}

In hindsight we should have done this forever, but ... 

/me grabs a large brown paperbag.

Debugged-by: Jack Ren &lt;jack.ren@marvell.com&gt;, 
Debugged-by: eric miao &lt;eric.y.miao@gmail.com&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>[ARM] dyntick: Remove obsolete and unused ARM dyntick support</title>
<updated>2008-05-12T16:39:14+00:00</updated>
<author>
<name>Russell King</name>
<email>rmk@dyn-67.arm.linux.org.uk</email>
</author>
<published>2008-04-20T12:57:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=205bee6ad804d7034773b5978c74dde495df2301'/>
<id>205bee6ad804d7034773b5978c74dde495df2301</id>
<content type='text'>
dyntick is superseded by the clocksource/clockevent infrastructure,
using the NO_HZ configuration option.  No one implements dyntick on
ARM anymore, so it's pointless keeping it around.  Remove dyntick
support.

Signed-off-by: Russell King &lt;rmk+kernel@arm.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
dyntick is superseded by the clocksource/clockevent infrastructure,
using the NO_HZ configuration option.  No one implements dyntick on
ARM anymore, so it's pointless keeping it around.  Remove dyntick
support.

Signed-off-by: Russell King &lt;rmk+kernel@arm.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>aout: remove unnecessary inclusions of {asm, linux}/a.out.h</title>
<updated>2008-02-08T17:22:30+00:00</updated>
<author>
<name>David Howells</name>
<email>dhowells@redhat.com</email>
</author>
<published>2008-02-08T12:19:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=1eb114112381eb66ebacdace1b6e70d30d603f9c'/>
<id>1eb114112381eb66ebacdace1b6e70d30d603f9c</id>
<content type='text'>
Remove now unnecessary inclusions of {asm,linux}/a.out.h.

[akpm@linux-foundation.org: fix alpha build]
Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
Cc: &lt;linux-arch@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Remove now unnecessary inclusions of {asm,linux}/a.out.h.

[akpm@linux-foundation.org: fix alpha build]
Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
Cc: &lt;linux-arch@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>aout: suppress A.OUT library support if !CONFIG_ARCH_SUPPORTS_AOUT</title>
<updated>2008-02-08T17:22:30+00:00</updated>
<author>
<name>David Howells</name>
<email>dhowells@redhat.com</email>
</author>
<published>2008-02-08T12:19:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=7fa3031500ec9b0a7460c8c23751799006ffee74'/>
<id>7fa3031500ec9b0a7460c8c23751799006ffee74</id>
<content type='text'>
Suppress A.OUT library support if CONFIG_ARCH_SUPPORTS_AOUT is not set.

Not all architectures support the A.OUT binfmt, so the ELF binfmt should not
be permitted to go looking for A.OUT libraries to load in such a case.  Not
only that, but under such conditions A.OUT core dumps are not produced either.

To make this work, this patch also does the following:

 (1) Makes the existence of the contents of linux/a.out.h contingent on
     CONFIG_ARCH_SUPPORTS_AOUT.

 (2) Renames dump_thread() to aout_dump_thread() as it's only called by A.OUT
     core dumping code.

 (3) Moves aout_dump_thread() into asm/a.out-core.h and makes it inline.  This
     is then included only where needed.  This means that this bit of arch
     code will be stored in the appropriate A.OUT binfmt module rather than
     the core kernel.

 (4) Drops A.OUT support for Blackfin (according to Mike Frysinger it's not
     needed) and FRV.

This patch depends on the previous patch to move STACK_TOP[_MAX] out of
asm/a.out.h and into asm/processor.h as they're required whether or not A.OUT
format is available.

[jdike@addtoit.com: uml: re-remove accidentally restored code]
Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
Cc: &lt;linux-arch@vger.kernel.org&gt;
Signed-off-by: Jeff Dike &lt;jdike@linux.intel.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Suppress A.OUT library support if CONFIG_ARCH_SUPPORTS_AOUT is not set.

Not all architectures support the A.OUT binfmt, so the ELF binfmt should not
be permitted to go looking for A.OUT libraries to load in such a case.  Not
only that, but under such conditions A.OUT core dumps are not produced either.

To make this work, this patch also does the following:

 (1) Makes the existence of the contents of linux/a.out.h contingent on
     CONFIG_ARCH_SUPPORTS_AOUT.

 (2) Renames dump_thread() to aout_dump_thread() as it's only called by A.OUT
     core dumping code.

 (3) Moves aout_dump_thread() into asm/a.out-core.h and makes it inline.  This
     is then included only where needed.  This means that this bit of arch
     code will be stored in the appropriate A.OUT binfmt module rather than
     the core kernel.

 (4) Drops A.OUT support for Blackfin (according to Mike Frysinger it's not
     needed) and FRV.

This patch depends on the previous patch to move STACK_TOP[_MAX] out of
asm/a.out.h and into asm/processor.h as they're required whether or not A.OUT
format is available.

[jdike@addtoit.com: uml: re-remove accidentally restored code]
Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
Cc: &lt;linux-arch@vger.kernel.org&gt;
Signed-off-by: Jeff Dike &lt;jdike@linux.intel.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Use helpers to obtain task pid in printks (arch code)</title>
<updated>2007-10-19T18:53:43+00:00</updated>
<author>
<name>Alexey Dobriyan</name>
<email>adobriyan@openvz.org</email>
</author>
<published>2007-10-19T06:40:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=19c5870c0eefd27c6d09d867465e0571262e05d0'/>
<id>19c5870c0eefd27c6d09d867465e0571262e05d0</id>
<content type='text'>
One of the easiest things to isolate is the pid printed in kernel log.
There was a patch, that made this for arch-independent code, this one makes
so for arch/xxx files.

It took some time to cross-compile it, but hopefully these are all the
printks in arch code.

Signed-off-by: Alexey Dobriyan &lt;adobriyan@openvz.org&gt;
Signed-off-by: Pavel Emelyanov &lt;xemul@openvz.org&gt;
Cc: &lt;linux-arch@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
One of the easiest things to isolate is the pid printed in kernel log.
There was a patch, that made this for arch-independent code, this one makes
so for arch/xxx files.

It took some time to cross-compile it, but hopefully these are all the
printks in arch code.

Signed-off-by: Alexey Dobriyan &lt;adobriyan@openvz.org&gt;
Signed-off-by: Pavel Emelyanov &lt;xemul@openvz.org&gt;
Cc: &lt;linux-arch@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>[ARM] 4453/1: Fully Decode ARM instruction set state in show_regs() tombstone</title>
<updated>2007-07-12T10:13:35+00:00</updated>
<author>
<name>George G. Davis</name>
<email>gdavis@mvista.com</email>
</author>
<published>2007-06-26T00:38:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=909d6c6c80311f800aee338e5fa528818b115951'/>
<id>909d6c6c80311f800aee338e5fa528818b115951</id>
<content type='text'>
The ARM show_regs() tombstone only partially decodes which ARM ISA was
executing at the time a fault occurred displaying either "(T)" for the
Thumb case or nothing at all for other cases.  This patch therefore
explicitly identifies which state the processor is in at the time of
a fault: ARM, Thumb, Jazelle or JazelleEE.

Signed-off-by: George G. Davis &lt;gdavis@mvista.com&gt;
Acked-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Signed-off-by: Russell King &lt;rmk+kernel@arm.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The ARM show_regs() tombstone only partially decodes which ARM ISA was
executing at the time a fault occurred displaying either "(T)" for the
Thumb case or nothing at all for other cases.  This patch therefore
explicitly identifies which state the processor is in at the time of
a fault: ARM, Thumb, Jazelle or JazelleEE.

Signed-off-by: George G. Davis &lt;gdavis@mvista.com&gt;
Acked-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Signed-off-by: Russell King &lt;rmk+kernel@arm.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>[ARM] Update show_regs/oops register format</title>
<updated>2007-06-18T14:04:42+00:00</updated>
<author>
<name>Russell King</name>
<email>rmk@dyn-67.arm.linux.org.uk</email>
</author>
<published>2007-06-18T13:59:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=154c772ebfb12ef66855510e6be2b12c85110b0c'/>
<id>154c772ebfb12ef66855510e6be2b12c85110b0c</id>
<content type='text'>
Add the kernel release and version information to the output of
show_regs/oops.  Add the CPU PSR register.  Avoid using printk
to output partial lines; always output a complete line.

Re-combine the "Control" and "Table + DAC" lines after nommu
separated them; we don't want to waste vertical screen space
needlessly.

Signed-off-by: Russell King &lt;rmk+kernel@arm.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add the kernel release and version information to the output of
show_regs/oops.  Add the CPU PSR register.  Avoid using printk
to output partial lines; always output a complete line.

Re-combine the "Control" and "Table + DAC" lines after nommu
separated them; we don't want to waste vertical screen space
needlessly.

Signed-off-by: Russell King &lt;rmk+kernel@arm.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>[ARM] 4258/2: Support for dynticks in idle loop</title>
<updated>2007-04-21T20:02:25+00:00</updated>
<author>
<name>Kevin Hilman</name>
<email>khilman@mvista.com</email>
</author>
<published>2007-03-14T16:33:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=9e4559ddffc012a73ea0b54ed3b6a219c1483ae9'/>
<id>9e4559ddffc012a73ea0b54ed3b6a219c1483ae9</id>
<content type='text'>
And, wrap timer_tick() and sysdev suspend/resume in
!GENERIC_CLOCKEVENTS since clockevent layer takes care
of these.

Signed-off-by: Kevin Hilman &lt;khilman@mvista.com&gt;
Acked-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Russell King &lt;rmk+kernel@arm.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
And, wrap timer_tick() and sysdev suspend/resume in
!GENERIC_CLOCKEVENTS since clockevent layer takes care
of these.

Signed-off-by: Kevin Hilman &lt;khilman@mvista.com&gt;
Acked-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Russell King &lt;rmk+kernel@arm.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
</feed>
