<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/drivers/char/esp.c, branch v2.6.25</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>drivers/char/esp.c: fix bootup lockup</title>
<updated>2008-03-07T18:05:13+00:00</updated>
<author>
<name>Ingo Molnar</name>
<email>mingo@elte.hu</email>
</author>
<published>2008-03-07T09:47:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=80d38f9a7871d9bafc3f244dabe48b41a58de705'/>
<id>80d38f9a7871d9bafc3f244dabe48b41a58de705</id>
<content type='text'>
randconfig testing found a bootup lockup in drivers/char/esp.c because
of a spinlock that wasn't correctly initialized.

I'm not sure why it became more prominent in 2.6.25-rc4, the bug seems
rather old and i've been doing allyesconfig bootups for ages with
CONFIG_ESP enabled.

This fixes this bootup lockup:

 PM: Adding info for No Bus:ttyP63
 ttyP32 at 0x0240 (irq = 0) is an ESP primary port
 BUG: spinlock lockup on CPU#0, swapper/1, f56dd004
 Pid: 1, comm: swapper Not tainted 2.6.25-rc4-sched-devel.git-x86-latest.git #402 [&lt;c03ac6f4&gt;] _raw_spin_lock+0x134/0x140
  [&lt;c08649be&gt;] _spin_lock_irqsave+0x5e/0x80
  [&lt;c0b9fbfe&gt;] ? espserial_init+0x2be/0x6e0
  [&lt;c0b9fbfe&gt;] espserial_init+0x2be/0x6e0
  [&lt;c0b877a3&gt;] kernel_init+0x83/0x260
  [&lt;c0b9f940&gt;] ? espserial_init+0x0/0x6e0
  [&lt;c010416a&gt;] ? restore_nocheck_notrace+0x0/0xe
  [&lt;c0b87720&gt;] ? kernel_init+0x0/0x260
  [&lt;c0b87720&gt;] ? kernel_init+0x0/0x260
  [&lt;c0104507&gt;] kernel_thread_helper+0x7/0x10
  =======================

kzalloc() is not the way to initialize spinlocks anymore.

Signed-off-by: Ingo Molnar &lt;mingo@elte.hu&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>
randconfig testing found a bootup lockup in drivers/char/esp.c because
of a spinlock that wasn't correctly initialized.

I'm not sure why it became more prominent in 2.6.25-rc4, the bug seems
rather old and i've been doing allyesconfig bootups for ages with
CONFIG_ESP enabled.

This fixes this bootup lockup:

 PM: Adding info for No Bus:ttyP63
 ttyP32 at 0x0240 (irq = 0) is an ESP primary port
 BUG: spinlock lockup on CPU#0, swapper/1, f56dd004
 Pid: 1, comm: swapper Not tainted 2.6.25-rc4-sched-devel.git-x86-latest.git #402 [&lt;c03ac6f4&gt;] _raw_spin_lock+0x134/0x140
  [&lt;c08649be&gt;] _spin_lock_irqsave+0x5e/0x80
  [&lt;c0b9fbfe&gt;] ? espserial_init+0x2be/0x6e0
  [&lt;c0b9fbfe&gt;] espserial_init+0x2be/0x6e0
  [&lt;c0b877a3&gt;] kernel_init+0x83/0x260
  [&lt;c0b9f940&gt;] ? espserial_init+0x0/0x6e0
  [&lt;c010416a&gt;] ? restore_nocheck_notrace+0x0/0xe
  [&lt;c0b87720&gt;] ? kernel_init+0x0/0x260
  [&lt;c0b87720&gt;] ? kernel_init+0x0/0x260
  [&lt;c0104507&gt;] kernel_thread_helper+0x7/0x10
  =======================

kzalloc() is not the way to initialize spinlocks anymore.

Signed-off-by: Ingo Molnar &lt;mingo@elte.hu&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Char: esp, remove hangup and wakeup bottomhalves</title>
<updated>2008-02-07T16:42:34+00:00</updated>
<author>
<name>Jiri Slaby</name>
<email>jirislaby@gmail.com</email>
</author>
<published>2008-02-07T08:16:37+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=d2e7a4b66d762cad383c5469c1e8b6076792ab6a'/>
<id>d2e7a4b66d762cad383c5469c1e8b6076792ab6a</id>
<content type='text'>
There is no need to schedule a bottomhalf for either of them. One is fast
and the another schedules a bottomhalf itself.

Signed-off-by: Jiri Slaby &lt;jirislaby@gmail.com&gt;
Acked-by: Alan Cox &lt;alan@redhat.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>
There is no need to schedule a bottomhalf for either of them. One is fast
and the another schedules a bottomhalf itself.

Signed-off-by: Jiri Slaby &lt;jirislaby@gmail.com&gt;
Acked-by: Alan Cox &lt;alan@redhat.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>Char: char/serial, remove SERIAL_TYPE_NORMAL redefines</title>
<updated>2008-02-07T16:42:33+00:00</updated>
<author>
<name>Jiri Slaby</name>
<email>jirislaby@gmail.com</email>
</author>
<published>2008-02-07T08:16:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=1237a2ef31cf60e01bbecbe198d8c002bbb710db'/>
<id>1237a2ef31cf60e01bbecbe198d8c002bbb710db</id>
<content type='text'>
Signed-off-by: Jiri Slaby &lt;jirislaby@gmail.com&gt;
Cc: Alan Cox &lt;alan@lxorguk.ukuu.org.uk&gt;
Cc: Alan Cox &lt;alan@lxorguk.ukuu.org.uk&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>
Signed-off-by: Jiri Slaby &lt;jirislaby@gmail.com&gt;
Cc: Alan Cox &lt;alan@lxorguk.ukuu.org.uk&gt;
Cc: Alan Cox &lt;alan@lxorguk.ukuu.org.uk&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>Convert files to UTF-8 and some cleanups</title>
<updated>2007-10-19T21:21:04+00:00</updated>
<author>
<name>Jan Engelhardt</name>
<email>jengelh@gmx.de</email>
</author>
<published>2007-10-19T21:21:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=96de0e252cedffad61b3cb5e05662c591898e69a'/>
<id>96de0e252cedffad61b3cb5e05662c591898e69a</id>
<content type='text'>
* Convert files to UTF-8.

  * Also correct some people's names
    (one example is Eißfeldt, which was found in a source file.
    Given that the author used an ß at all in a source file
    indicates that the real name has in fact a 'ß' and not an 'ss',
    which is commonly used as a substitute for 'ß' when limited to
    7bit.)

  * Correct town names (Goettingen -&gt; Göttingen)

  * Update Eberhard Mönkeberg's address (http://lkml.org/lkml/2007/1/8/313)

Signed-off-by: Jan Engelhardt &lt;jengelh@gmx.de&gt;
Signed-off-by: Adrian Bunk &lt;bunk@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
* Convert files to UTF-8.

  * Also correct some people's names
    (one example is Eißfeldt, which was found in a source file.
    Given that the author used an ß at all in a source file
    indicates that the real name has in fact a 'ß' and not an 'ss',
    which is commonly used as a substitute for 'ß' when limited to
    7bit.)

  * Correct town names (Goettingen -&gt; Göttingen)

  * Update Eberhard Mönkeberg's address (http://lkml.org/lkml/2007/1/8/313)

Signed-off-by: Jan Engelhardt &lt;jengelh@gmx.de&gt;
Signed-off-by: Adrian Bunk &lt;bunk@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>remove asm/bitops.h includes</title>
<updated>2007-10-19T18:53:41+00:00</updated>
<author>
<name>Jiri Slaby</name>
<email>jirislaby@gmail.com</email>
</author>
<published>2007-10-19T06:40:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=1977f032722c27ee3730284582fd3991ad9ac81b'/>
<id>1977f032722c27ee3730284582fd3991ad9ac81b</id>
<content type='text'>
remove asm/bitops.h includes

including asm/bitops directly may cause compile errors. don't include it
and include linux/bitops instead. next patch will deny including asm header
directly.

Cc: Adrian Bunk &lt;bunk@kernel.org&gt;
Signed-off-by: Jiri Slaby &lt;jirislaby@gmail.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>
remove asm/bitops.h includes

including asm/bitops directly may cause compile errors. don't include it
and include linux/bitops instead. next patch will deny including asm header
directly.

Cc: Adrian Bunk &lt;bunk@kernel.org&gt;
Signed-off-by: Jiri Slaby &lt;jirislaby@gmail.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>some kmalloc/memset -&gt;kzalloc (tree wide)</title>
<updated>2007-07-19T17:04:50+00:00</updated>
<author>
<name>Yoann Padioleau</name>
<email>padator@wanadoo.fr</email>
</author>
<published>2007-07-19T08:49:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=dd00cc486ab1c17049a535413d1751ef3482141c'/>
<id>dd00cc486ab1c17049a535413d1751ef3482141c</id>
<content type='text'>
Transform some calls to kmalloc/memset to a single kzalloc (or kcalloc).

Here is a short excerpt of the semantic patch performing
this transformation:

@@
type T2;
expression x;
identifier f,fld;
expression E;
expression E1,E2;
expression e1,e2,e3,y;
statement S;
@@

 x =
- kmalloc
+ kzalloc
  (E1,E2)
  ...  when != \(x-&gt;fld=E;\|y=f(...,x,...);\|f(...,x,...);\|x=E;\|while(...) S\|for(e1;e2;e3) S\)
- memset((T2)x,0,E1);

@@
expression E1,E2,E3;
@@

- kzalloc(E1 * E2,E3)
+ kcalloc(E1,E2,E3)

[akpm@linux-foundation.org: get kcalloc args the right way around]
Signed-off-by: Yoann Padioleau &lt;padator@wanadoo.fr&gt;
Cc: Richard Henderson &lt;rth@twiddle.net&gt;
Cc: Ivan Kokshaysky &lt;ink@jurassic.park.msu.ru&gt;
Acked-by: Russell King &lt;rmk@arm.linux.org.uk&gt;
Cc: Bryan Wu &lt;bryan.wu@analog.com&gt;
Acked-by: Jiri Slaby &lt;jirislaby@gmail.com&gt;
Cc: Dave Airlie &lt;airlied@linux.ie&gt;
Acked-by: Roland Dreier &lt;rolandd@cisco.com&gt;
Cc: Jiri Kosina &lt;jkosina@suse.cz&gt;
Acked-by: Dmitry Torokhov &lt;dtor@mail.ru&gt;
Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Acked-by: Mauro Carvalho Chehab &lt;mchehab@infradead.org&gt;
Acked-by: Pierre Ossman &lt;drzeus-list@drzeus.cx&gt;
Cc: Jeff Garzik &lt;jeff@garzik.org&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Acked-by: Greg KH &lt;greg@kroah.com&gt;
Cc: James Bottomley &lt;James.Bottomley@steeleye.com&gt;
Cc: "Antonino A. Daplas" &lt;adaplas@pol.net&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>
Transform some calls to kmalloc/memset to a single kzalloc (or kcalloc).

Here is a short excerpt of the semantic patch performing
this transformation:

@@
type T2;
expression x;
identifier f,fld;
expression E;
expression E1,E2;
expression e1,e2,e3,y;
statement S;
@@

 x =
- kmalloc
+ kzalloc
  (E1,E2)
  ...  when != \(x-&gt;fld=E;\|y=f(...,x,...);\|f(...,x,...);\|x=E;\|while(...) S\|for(e1;e2;e3) S\)
- memset((T2)x,0,E1);

@@
expression E1,E2,E3;
@@

- kzalloc(E1 * E2,E3)
+ kcalloc(E1,E2,E3)

[akpm@linux-foundation.org: get kcalloc args the right way around]
Signed-off-by: Yoann Padioleau &lt;padator@wanadoo.fr&gt;
Cc: Richard Henderson &lt;rth@twiddle.net&gt;
Cc: Ivan Kokshaysky &lt;ink@jurassic.park.msu.ru&gt;
Acked-by: Russell King &lt;rmk@arm.linux.org.uk&gt;
Cc: Bryan Wu &lt;bryan.wu@analog.com&gt;
Acked-by: Jiri Slaby &lt;jirislaby@gmail.com&gt;
Cc: Dave Airlie &lt;airlied@linux.ie&gt;
Acked-by: Roland Dreier &lt;rolandd@cisco.com&gt;
Cc: Jiri Kosina &lt;jkosina@suse.cz&gt;
Acked-by: Dmitry Torokhov &lt;dtor@mail.ru&gt;
Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Acked-by: Mauro Carvalho Chehab &lt;mchehab@infradead.org&gt;
Acked-by: Pierre Ossman &lt;drzeus-list@drzeus.cx&gt;
Cc: Jeff Garzik &lt;jeff@garzik.org&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Acked-by: Greg KH &lt;greg@kroah.com&gt;
Cc: James Bottomley &lt;James.Bottomley@steeleye.com&gt;
Cc: "Antonino A. Daplas" &lt;adaplas@pol.net&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>serial: remove termios checks from various old char serial drivers</title>
<updated>2007-07-16T16:05:52+00:00</updated>
<author>
<name>Alan Cox</name>
<email>alan@lxorguk.ukuu.org.uk</email>
</author>
<published>2007-07-16T06:41:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=7e7d136e9e083f04b859411248c699cbb89e418d'/>
<id>7e7d136e9e083f04b859411248c699cbb89e418d</id>
<content type='text'>
Signed-off-by: Alan Cox &lt;alan@redhat.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>
Signed-off-by: Alan Cox &lt;alan@redhat.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>[PATCH] tty: switch to ktermios</title>
<updated>2006-12-08T16:28:57+00:00</updated>
<author>
<name>Alan Cox</name>
<email>alan@lxorguk.ukuu.org.uk</email>
</author>
<published>2006-12-08T10:38:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=606d099cdd1080bbb50ea50dc52d98252f8f10a1'/>
<id>606d099cdd1080bbb50ea50dc52d98252f8f10a1</id>
<content type='text'>
This is the grungy swap all the occurrences in the right places patch that
goes with the updates.  At this point we have the same functionality as
before (except that sgttyb() returns speeds not zero) and are ready to
begin turning new stuff on providing nobody reports lots of bugs

If you are a tty driver author converting an out of tree driver the only
impact should be termios-&gt;ktermios name changes for the speed/property
setting functions from your upper layers.

If you are implementing your own TCGETS function before then your driver
was broken already and its about to get a whole lot more painful for you so
please fix it 8)

Also fill in c_ispeed/ospeed on init for most devices, although the current
code will do this for you anyway but I'd like eventually to lose that extra
paranoia

[akpm@osdl.org: bluetooth fix]
[mp3@de.ibm.com: sclp fix]
[mp3@de.ibm.com: warning fix for tty3270]
[hugh@veritas.com: fix tty_ioctl powerpc build]
[jdike@addtoit.com: uml: fix -&gt;set_termios declaration]
Signed-off-by: Alan Cox &lt;alan@redhat.com&gt;
Signed-off-by: Martin Peschke &lt;mp3@de.ibm.com&gt;
Acked-by: Peter Oberparleiter &lt;oberpar@de.ibm.com&gt;
Cc: Cornelia Huck &lt;cornelia.huck@de.ibm.com&gt;
Signed-off-by: Hugh Dickins &lt;hugh@veritas.com&gt;
Signed-off-by: Jeff Dike &lt;jdike@addtoit.com&gt;
Cc: Paolo 'Blaisorblade' Giarrusso &lt;blaisorblade@yahoo.it&gt;
Signed-off-by: Andrew Morton &lt;akpm@osdl.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@osdl.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This is the grungy swap all the occurrences in the right places patch that
goes with the updates.  At this point we have the same functionality as
before (except that sgttyb() returns speeds not zero) and are ready to
begin turning new stuff on providing nobody reports lots of bugs

If you are a tty driver author converting an out of tree driver the only
impact should be termios-&gt;ktermios name changes for the speed/property
setting functions from your upper layers.

If you are implementing your own TCGETS function before then your driver
was broken already and its about to get a whole lot more painful for you so
please fix it 8)

Also fill in c_ispeed/ospeed on init for most devices, although the current
code will do this for you anyway but I'd like eventually to lose that extra
paranoia

[akpm@osdl.org: bluetooth fix]
[mp3@de.ibm.com: sclp fix]
[mp3@de.ibm.com: warning fix for tty3270]
[hugh@veritas.com: fix tty_ioctl powerpc build]
[jdike@addtoit.com: uml: fix -&gt;set_termios declaration]
Signed-off-by: Alan Cox &lt;alan@redhat.com&gt;
Signed-off-by: Martin Peschke &lt;mp3@de.ibm.com&gt;
Acked-by: Peter Oberparleiter &lt;oberpar@de.ibm.com&gt;
Cc: Cornelia Huck &lt;cornelia.huck@de.ibm.com&gt;
Signed-off-by: Hugh Dickins &lt;hugh@veritas.com&gt;
Signed-off-by: Jeff Dike &lt;jdike@addtoit.com&gt;
Cc: Paolo 'Blaisorblade' Giarrusso &lt;blaisorblade@yahoo.it&gt;
Signed-off-by: Andrew Morton &lt;akpm@osdl.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@osdl.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>WorkStruct: make allyesconfig</title>
<updated>2006-11-22T14:57:56+00:00</updated>
<author>
<name>David Howells</name>
<email>dhowells@redhat.com</email>
</author>
<published>2006-11-22T14:57:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=c4028958b6ecad064b1a6303a6a5906d4fe48d73'/>
<id>c4028958b6ecad064b1a6303a6a5906d4fe48d73</id>
<content type='text'>
Fix up for make allyesconfig.

Signed-Off-By: David Howells &lt;dhowells@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Fix up for make allyesconfig.

Signed-Off-By: David Howells &lt;dhowells@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>IRQ: Maintain regs pointer globally rather than passing to IRQ handlers</title>
<updated>2006-10-05T14:10:12+00:00</updated>
<author>
<name>David Howells</name>
<email>dhowells@redhat.com</email>
</author>
<published>2006-10-05T13:55:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=7d12e780e003f93433d49ce78cfedf4b4c52adc5'/>
<id>7d12e780e003f93433d49ce78cfedf4b4c52adc5</id>
<content type='text'>
Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.

The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around.  On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).

Where appropriate, an arch may override the generic storage facility and do
something different with the variable.  On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.

Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions.  Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller.  A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.

I've build this code with allyesconfig for x86_64 and i386.  I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.

This will affect all archs.  Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:

	struct pt_regs *old_regs = set_irq_regs(regs);

And put the old one back at the end:

	set_irq_regs(old_regs);

Don't pass regs through to generic_handle_irq() or __do_IRQ().

In timer_interrupt(), this sort of change will be necessary:

	-	update_process_times(user_mode(regs));
	-	profile_tick(CPU_PROFILING, regs);
	+	update_process_times(user_mode(get_irq_regs()));
	+	profile_tick(CPU_PROFILING);

I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().

Some notes on the interrupt handling in the drivers:

 (*) input_dev() is now gone entirely.  The regs pointer is no longer stored in
     the input_dev struct.

 (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking.  It does
     something different depending on whether it's been supplied with a regs
     pointer or not.

 (*) Various IRQ handler function pointers have been moved to type
     irq_handler_t.

Signed-Off-By: David Howells &lt;dhowells@redhat.com&gt;
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
</content>
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<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.

The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around.  On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).

Where appropriate, an arch may override the generic storage facility and do
something different with the variable.  On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.

Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions.  Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller.  A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.

I've build this code with allyesconfig for x86_64 and i386.  I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.

This will affect all archs.  Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:

	struct pt_regs *old_regs = set_irq_regs(regs);

And put the old one back at the end:

	set_irq_regs(old_regs);

Don't pass regs through to generic_handle_irq() or __do_IRQ().

In timer_interrupt(), this sort of change will be necessary:

	-	update_process_times(user_mode(regs));
	-	profile_tick(CPU_PROFILING, regs);
	+	update_process_times(user_mode(get_irq_regs()));
	+	profile_tick(CPU_PROFILING);

I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().

Some notes on the interrupt handling in the drivers:

 (*) input_dev() is now gone entirely.  The regs pointer is no longer stored in
     the input_dev struct.

 (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking.  It does
     something different depending on whether it's been supplied with a regs
     pointer or not.

 (*) Various IRQ handler function pointers have been moved to type
     irq_handler_t.

Signed-Off-By: David Howells &lt;dhowells@redhat.com&gt;
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
</pre>
</div>
</content>
</entry>
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