<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/arch/xtensa/include, branch v3.17</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge tag 'xtensa-for-next-20140815' into for_next</title>
<updated>2014-08-19T00:30:24+00:00</updated>
<author>
<name>Chris Zankel</name>
<email>chris@zankel.net</email>
</author>
<published>2014-08-19T00:30:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=e792290be763932d1b8cdf8a36d7015482a49d07'/>
<id>e792290be763932d1b8cdf8a36d7015482a49d07</id>
<content type='text'>
Xtensa improvements for 3.17:
- support highmem on cores with aliasing data cache. Enable highmem on kc705
  by default;
- simplify addition of new core variants (no need to modify Kconfig /
  Makefiles);
- improve robustness of unaligned access handler and its interaction with
  window overflow/underflow exception handlers;
- deprecate atomic and spill registers syscalls;
- clean up Kconfig: remove orphan MATH_EMULATION, sort 'select' statements;
- wire up renameat2 syscall.

Various fixes:
- fix address checks in dma_{alloc,free}_coherent (runtime BUG);
- fix access to THREAD_RA/THREAD_SP/THREAD_DS (debug build breakage);
- fix TLBTEMP_BASE_2 region handling in fast_second_level_miss (runtime
  unrecoverable exception);
- fix a6 and a7 handling in fast_syscall_xtensa (runtime userspace register
  clobbering);
- fix kernel/user jump out of fast_unaligned (potential runtime unrecoverable
  exception);
- replace termios IOCTL code definitions with constants (userspace build
  breakage).

Signed-off-by: Chris Zankel &lt;chris@zankel.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Xtensa improvements for 3.17:
- support highmem on cores with aliasing data cache. Enable highmem on kc705
  by default;
- simplify addition of new core variants (no need to modify Kconfig /
  Makefiles);
- improve robustness of unaligned access handler and its interaction with
  window overflow/underflow exception handlers;
- deprecate atomic and spill registers syscalls;
- clean up Kconfig: remove orphan MATH_EMULATION, sort 'select' statements;
- wire up renameat2 syscall.

Various fixes:
- fix address checks in dma_{alloc,free}_coherent (runtime BUG);
- fix access to THREAD_RA/THREAD_SP/THREAD_DS (debug build breakage);
- fix TLBTEMP_BASE_2 region handling in fast_second_level_miss (runtime
  unrecoverable exception);
- fix a6 and a7 handling in fast_syscall_xtensa (runtime userspace register
  clobbering);
- fix kernel/user jump out of fast_unaligned (potential runtime unrecoverable
  exception);
- replace termios IOCTL code definitions with constants (userspace build
  breakage).

Signed-off-by: Chris Zankel &lt;chris@zankel.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>xtensa: support aliasing cache in kmap</title>
<updated>2014-08-14T07:59:22+00:00</updated>
<author>
<name>Max Filippov</name>
<email>jcmvbkbc@gmail.com</email>
</author>
<published>2014-07-17T01:04:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=8504b503dfa86f698a38f9ee1fc2876ab012b776'/>
<id>8504b503dfa86f698a38f9ee1fc2876ab012b776</id>
<content type='text'>
Define ARCH_PKMAP_COLORING and provide corresponding macro definitions
on cores with aliasing data cache.

Instead of single last_pkmap_nr maintain an array last_pkmap_nr_arr of
pkmap counters for each page color. Make sure that kmap maps physical
page at virtual address with color matching its physical address.

Signed-off-by: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Define ARCH_PKMAP_COLORING and provide corresponding macro definitions
on cores with aliasing data cache.

Instead of single last_pkmap_nr maintain an array last_pkmap_nr_arr of
pkmap counters for each page color. Make sure that kmap maps physical
page at virtual address with color matching its physical address.

Signed-off-by: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>xtensa: support aliasing cache in k[un]map_atomic</title>
<updated>2014-08-14T07:59:21+00:00</updated>
<author>
<name>Max Filippov</name>
<email>jcmvbkbc@gmail.com</email>
</author>
<published>2014-07-14T22:51:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=32544d9c10c42bac3be8b87d2fc95b0aef008795'/>
<id>32544d9c10c42bac3be8b87d2fc95b0aef008795</id>
<content type='text'>
Map high memory pages at virtual addresses with color that match color
of their physical address. Existing cache alias management mechanisms
may be used with such pages.

Signed-off-by: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Map high memory pages at virtual addresses with color that match color
of their physical address. Existing cache alias management mechanisms
may be used with such pages.

Signed-off-by: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>xtensa: implement clear_user_highpage and copy_user_highpage</title>
<updated>2014-08-14T07:59:20+00:00</updated>
<author>
<name>Max Filippov</name>
<email>jcmvbkbc@gmail.com</email>
</author>
<published>2014-07-21T14:54:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=a91902db2990909ea5e6b110811b448f2e8f1571'/>
<id>a91902db2990909ea5e6b110811b448f2e8f1571</id>
<content type='text'>
Existing clear_user_page and copy_user_page cannot be used with highmem
because they calculate physical page address from its virtual address
and do it incorrectly in case of high memory page mapped with
kmap_atomic. Also kmap is not needed, as most likely userspace mapping
color would be different from the kmapped color.

Provide clear_user_highpage and copy_user_highpage functions that
determine if temporary mapping is needed for the pages. Move most of the
logic of the former clear_user_page and copy_user_page to
xtensa/mm/cache.c only leaving temporary mapping setup, invalidation and
clearing/copying in the xtensa/mm/misc.S. Rename these functions to
clear_page_alias and copy_page_alias.

Signed-off-by: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Existing clear_user_page and copy_user_page cannot be used with highmem
because they calculate physical page address from its virtual address
and do it incorrectly in case of high memory page mapped with
kmap_atomic. Also kmap is not needed, as most likely userspace mapping
color would be different from the kmapped color.

Provide clear_user_highpage and copy_user_highpage functions that
determine if temporary mapping is needed for the pages. Move most of the
logic of the former clear_user_page and copy_user_page to
xtensa/mm/cache.c only leaving temporary mapping setup, invalidation and
clearing/copying in the xtensa/mm/misc.S. Rename these functions to
clear_page_alias and copy_page_alias.

Signed-off-by: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>xtensa: fix TLBTEMP_BASE_2 region handling in fast_second_level_miss</title>
<updated>2014-08-14T07:59:19+00:00</updated>
<author>
<name>Max Filippov</name>
<email>jcmvbkbc@gmail.com</email>
</author>
<published>2014-07-21T18:01:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=7128039fe2dd3d59da9e4ffa036f3aaa3ba87b9f'/>
<id>7128039fe2dd3d59da9e4ffa036f3aaa3ba87b9f</id>
<content type='text'>
Current definition of TLBTEMP_BASE_2 is always 32K above the
TLBTEMP_BASE_1, whereas fast_second_level_miss handler for the TLBTEMP
region analyzes virtual address bit (PAGE_SHIFT + DCACHE_ALIAS_ORDER)
to determine TLBTEMP region where the fault happened. The size of the
TLBTEMP region is also checked incorrectly: not 64K, but twice data
cache way size (whicht may as well be less than the instruction cache
way size).

Fix TLBTEMP_BASE_2 to be TLBTEMP_BASE_1 + data cache way size.
Provide TLBTEMP_SIZE that is a greater of doubled data cache way size or
the instruction cache way size, and use it to determine if the second
level TLB miss occured in the TLBTEMP region.

Practical occurence of page faults in the TLBTEMP area is extremely
rare, this code can be tested by deletion of all w[di]tlb instructions
in the tlbtemp_mapping region.

Cc: stable@vger.kernel.org
Signed-off-by: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Current definition of TLBTEMP_BASE_2 is always 32K above the
TLBTEMP_BASE_1, whereas fast_second_level_miss handler for the TLBTEMP
region analyzes virtual address bit (PAGE_SHIFT + DCACHE_ALIAS_ORDER)
to determine TLBTEMP region where the fault happened. The size of the
TLBTEMP region is also checked incorrectly: not 64K, but twice data
cache way size (whicht may as well be less than the instruction cache
way size).

Fix TLBTEMP_BASE_2 to be TLBTEMP_BASE_1 + data cache way size.
Provide TLBTEMP_SIZE that is a greater of doubled data cache way size or
the instruction cache way size, and use it to determine if the second
level TLB miss occured in the TLBTEMP region.

Practical occurence of page faults in the TLBTEMP area is extremely
rare, this code can be tested by deletion of all w[di]tlb instructions
in the tlbtemp_mapping region.

Cc: stable@vger.kernel.org
Signed-off-by: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>xtensa: make fixmap region addressing grow with index</title>
<updated>2014-08-14T07:59:17+00:00</updated>
<author>
<name>Max Filippov</name>
<email>jcmvbkbc@gmail.com</email>
</author>
<published>2014-07-14T22:27:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=22def7681186f65f4f1256ae9b0b6db2a7720cb1'/>
<id>22def7681186f65f4f1256ae9b0b6db2a7720cb1</id>
<content type='text'>
It's much easier to reason about alignment and coloring of regions
located in the fixmap when fixmap index is just a PFN within the fixmap
region. Change fixmap addressing so that index 0 corresponds to
FIXADDR_START instead of the FIXADDR_TOP.

Signed-off-by: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
It's much easier to reason about alignment and coloring of regions
located in the fixmap when fixmap index is just a PFN within the fixmap
region. Change fixmap addressing so that index 0 corresponds to
FIXADDR_START instead of the FIXADDR_TOP.

Signed-off-by: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>xtensa: fix access to THREAD_RA/THREAD_SP/THREAD_DS</title>
<updated>2014-08-14T07:59:16+00:00</updated>
<author>
<name>Max Filippov</name>
<email>jcmvbkbc@gmail.com</email>
</author>
<published>2014-07-27T03:23:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=52247123749cc3cbc30168b33ad8c69515c96d23'/>
<id>52247123749cc3cbc30168b33ad8c69515c96d23</id>
<content type='text'>
With SMP and a lot of debug options enabled task_struct::thread gets out
of reach of s32i/l32i instructions with base pointing at task_struct,
breaking build with the following messages:

  arch/xtensa/kernel/entry.S: Assembler messages:
  arch/xtensa/kernel/entry.S:1002: Error: operand 3 of 'l32i.n' has invalid value '1048'
  arch/xtensa/kernel/entry.S:1831: Error: operand 3 of 's32i.n' has invalid value '1040'
  arch/xtensa/kernel/entry.S:1832: Error: operand 3 of 's32i.n' has invalid value '1044'

Change base to point to task_struct::thread in such cases.
Don't use a10 in _switch_to to save/restore prev pointer as a2 is not
clobbered.

Cc: stable@vger.kernel.org
Signed-off-by: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
With SMP and a lot of debug options enabled task_struct::thread gets out
of reach of s32i/l32i instructions with base pointing at task_struct,
breaking build with the following messages:

  arch/xtensa/kernel/entry.S: Assembler messages:
  arch/xtensa/kernel/entry.S:1002: Error: operand 3 of 'l32i.n' has invalid value '1048'
  arch/xtensa/kernel/entry.S:1831: Error: operand 3 of 's32i.n' has invalid value '1040'
  arch/xtensa/kernel/entry.S:1832: Error: operand 3 of 's32i.n' has invalid value '1044'

Change base to point to task_struct::thread in such cases.
Don't use a10 in _switch_to to save/restore prev pointer as a2 is not
clobbered.

Cc: stable@vger.kernel.org
Signed-off-by: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>xtensa: add renameat2 syscall</title>
<updated>2014-08-14T07:59:15+00:00</updated>
<author>
<name>Miklos Szeredi</name>
<email>mszeredi@suse.cz</email>
</author>
<published>2014-04-11T10:25:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=89f77c6f5bb4b0058f40f510809ec07255e02a7e'/>
<id>89f77c6f5bb4b0058f40f510809ec07255e02a7e</id>
<content type='text'>
Signed-off-by: Miklos Szeredi &lt;mszeredi@suse.cz&gt;
Cc: Chris Zankel &lt;chris@zankel.net&gt;
Signed-off-by: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Signed-off-by: Miklos Szeredi &lt;mszeredi@suse.cz&gt;
Cc: Chris Zankel &lt;chris@zankel.net&gt;
Signed-off-by: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>xtensa: replace IOCTL code definitions with constants</title>
<updated>2014-08-14T07:59:13+00:00</updated>
<author>
<name>Max Filippov</name>
<email>jcmvbkbc@gmail.com</email>
</author>
<published>2014-07-19T23:38:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f61bf8e7d19e0a3456a7a9ed97c399e4353698dc'/>
<id>f61bf8e7d19e0a3456a7a9ed97c399e4353698dc</id>
<content type='text'>
This fixes userspace code that builds on other architectures but fails
on xtensa due to references to structures that other architectures don't
refer to. E.g. this fixes the following issue with python-2.7.8:

  python-2.7.8/Modules/termios.c:861:25: error: invalid application
     of 'sizeof' to incomplete type 'struct serial_multiport_struct'
     {"TIOCSERGETMULTI", TIOCSERGETMULTI},
  python-2.7.8/Modules/termios.c:870:25: error: invalid application
     of 'sizeof' to incomplete type 'struct serial_multiport_struct'
     {"TIOCSERSETMULTI", TIOCSERSETMULTI},
  python-2.7.8/Modules/termios.c:900:24: error: invalid application
     of 'sizeof' to incomplete type 'struct tty_struct'
     {"TIOCTTYGSTRUCT", TIOCTTYGSTRUCT},

Cc: stable@vger.kernel.org
Signed-off-by: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This fixes userspace code that builds on other architectures but fails
on xtensa due to references to structures that other architectures don't
refer to. E.g. this fixes the following issue with python-2.7.8:

  python-2.7.8/Modules/termios.c:861:25: error: invalid application
     of 'sizeof' to incomplete type 'struct serial_multiport_struct'
     {"TIOCSERGETMULTI", TIOCSERGETMULTI},
  python-2.7.8/Modules/termios.c:870:25: error: invalid application
     of 'sizeof' to incomplete type 'struct serial_multiport_struct'
     {"TIOCSERSETMULTI", TIOCSERSETMULTI},
  python-2.7.8/Modules/termios.c:900:24: error: invalid application
     of 'sizeof' to incomplete type 'struct tty_struct'
     {"TIOCTTYGSTRUCT", TIOCTTYGSTRUCT},

Cc: stable@vger.kernel.org
Signed-off-by: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arch, locking: Ciao arch_mutex_cpu_relax()</title>
<updated>2014-07-17T10:32:47+00:00</updated>
<author>
<name>Davidlohr Bueso</name>
<email>davidlohr@hp.com</email>
</author>
<published>2014-06-29T22:09:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=3a6bfbc91df04b081a44d419e0260bad54abddf7'/>
<id>3a6bfbc91df04b081a44d419e0260bad54abddf7</id>
<content type='text'>
The arch_mutex_cpu_relax() function, introduced by 34b133f, is
hacky and ugly. It was added a few years ago to address the fact
that common cpu_relax() calls include yielding on s390, and thus
impact the optimistic spinning functionality of mutexes. Nowadays
we use this function well beyond mutexes: rwsem, qrwlock, mcs and
lockref. Since the macro that defines the call is in the mutex header,
any users must include mutex.h and the naming is misleading as well.

This patch (i) renames the call to cpu_relax_lowlatency  ("relax, but
only if you can do it with very low latency") and (ii) defines it in
each arch's asm/processor.h local header, just like for regular cpu_relax
functions. On all archs, except s390, cpu_relax_lowlatency is simply cpu_relax,
and thus we can take it out of mutex.h. While this can seem redundant,
I believe it is a good choice as it allows us to move out arch specific
logic from generic locking primitives and enables future(?) archs to
transparently define it, similarly to System Z.

Signed-off-by: Davidlohr Bueso &lt;davidlohr@hp.com&gt;
Signed-off-by: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Anton Blanchard &lt;anton@samba.org&gt;
Cc: Aurelien Jacquiot &lt;a-jacquiot@ti.com&gt;
Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: Bharat Bhushan &lt;r65777@freescale.com&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Chen Liqin &lt;liqin.linux@gmail.com&gt;
Cc: Chris Metcalf &lt;cmetcalf@tilera.com&gt;
Cc: Christian Borntraeger &lt;borntraeger@de.ibm.com&gt;
Cc: Chris Zankel &lt;chris@zankel.net&gt;
Cc: David Howells &lt;dhowells@redhat.com&gt;
Cc: David S. Miller &lt;davem@davemloft.net&gt;
Cc: Deepthi Dharwar &lt;deepthi@linux.vnet.ibm.com&gt;
Cc: Dominik Dingel &lt;dingel@linux.vnet.ibm.com&gt;
Cc: Fenghua Yu &lt;fenghua.yu@intel.com&gt;
Cc: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Cc: Guan Xuetao &lt;gxt@mprc.pku.edu.cn&gt;
Cc: Haavard Skinnemoen &lt;hskinnemoen@gmail.com&gt;
Cc: Hans-Christian Egtvedt &lt;egtvedt@samfundet.no&gt;
Cc: Heiko Carstens &lt;heiko.carstens@de.ibm.com&gt;
Cc: Helge Deller &lt;deller@gmx.de&gt;
Cc: Hirokazu Takata &lt;takata@linux-m32r.org&gt;
Cc: Ivan Kokshaysky &lt;ink@jurassic.park.msu.ru&gt;
Cc: James E.J. Bottomley &lt;jejb@parisc-linux.org&gt;
Cc: James Hogan &lt;james.hogan@imgtec.com&gt;
Cc: Jason Wang &lt;jasowang@redhat.com&gt;
Cc: Jesper Nilsson &lt;jesper.nilsson@axis.com&gt;
Cc: Joe Perches &lt;joe@perches.com&gt;
Cc: Jonas Bonn &lt;jonas@southpole.se&gt;
Cc: Joseph Myers &lt;joseph@codesourcery.com&gt;
Cc: Kees Cook &lt;keescook@chromium.org&gt;
Cc: Koichi Yasutake &lt;yasutake.koichi@jp.panasonic.com&gt;
Cc: Lennox Wu &lt;lennox.wu@gmail.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Mark Salter &lt;msalter@redhat.com&gt;
Cc: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
Cc: Matt Turner &lt;mattst88@gmail.com&gt;
Cc: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
Cc: Michael Neuling &lt;mikey@neuling.org&gt;
Cc: Michal Simek &lt;monstr@monstr.eu&gt;
Cc: Mikael Starvik &lt;starvik@axis.com&gt;
Cc: Nicolas Pitre &lt;nico@linaro.org&gt;
Cc: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Cc: Paul Burton &lt;paul.burton@imgtec.com&gt;
Cc: Paul E. McKenney &lt;paulmck@linux.vnet.ibm.com&gt;
Cc: Paul Gortmaker &lt;paul.gortmaker@windriver.com&gt;
Cc: Paul Mackerras &lt;paulus@samba.org&gt;
Cc: Qais Yousef &lt;qais.yousef@imgtec.com&gt;
Cc: Qiaowei Ren &lt;qiaowei.ren@intel.com&gt;
Cc: Rafael Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Cc: Ralf Baechle &lt;ralf@linux-mips.org&gt;
Cc: Richard Henderson &lt;rth@twiddle.net&gt;
Cc: Richard Kuo &lt;rkuo@codeaurora.org&gt;
Cc: Russell King &lt;linux@arm.linux.org.uk&gt;
Cc: Steven Miao &lt;realmz6@gmail.com&gt;
Cc: Steven Rostedt &lt;srostedt@redhat.com&gt;
Cc: Stratos Karafotis &lt;stratosk@semaphore.gr&gt;
Cc: Tim Chen &lt;tim.c.chen@linux.intel.com&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Cc: Vasily Kulikov &lt;segoon@openwall.com&gt;
Cc: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Cc: Vineet Gupta &lt;Vineet.Gupta1@synopsys.com&gt;
Cc: Waiman Long &lt;Waiman.Long@hp.com&gt;
Cc: Will Deacon &lt;will.deacon@arm.com&gt;
Cc: Wolfram Sang &lt;wsa@the-dreams.de&gt;
Cc: adi-buildroot-devel@lists.sourceforge.net
Cc: linux390@de.ibm.com
Cc: linux-alpha@vger.kernel.org
Cc: linux-am33-list@redhat.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-c6x-dev@linux-c6x.org
Cc: linux-cris-kernel@axis.com
Cc: linux-hexagon@vger.kernel.org
Cc: linux-ia64@vger.kernel.org
Cc: linux@lists.openrisc.net
Cc: linux-m32r-ja@ml.linux-m32r.org
Cc: linux-m32r@ml.linux-m32r.org
Cc: linux-m68k@lists.linux-m68k.org
Cc: linux-metag@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: linux-xtensa@linux-xtensa.org
Cc: sparclinux@vger.kernel.org
Link: http://lkml.kernel.org/r/1404079773.2619.4.camel@buesod1.americas.hpqcorp.net
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
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The arch_mutex_cpu_relax() function, introduced by 34b133f, is
hacky and ugly. It was added a few years ago to address the fact
that common cpu_relax() calls include yielding on s390, and thus
impact the optimistic spinning functionality of mutexes. Nowadays
we use this function well beyond mutexes: rwsem, qrwlock, mcs and
lockref. Since the macro that defines the call is in the mutex header,
any users must include mutex.h and the naming is misleading as well.

This patch (i) renames the call to cpu_relax_lowlatency  ("relax, but
only if you can do it with very low latency") and (ii) defines it in
each arch's asm/processor.h local header, just like for regular cpu_relax
functions. On all archs, except s390, cpu_relax_lowlatency is simply cpu_relax,
and thus we can take it out of mutex.h. While this can seem redundant,
I believe it is a good choice as it allows us to move out arch specific
logic from generic locking primitives and enables future(?) archs to
transparently define it, similarly to System Z.

Signed-off-by: Davidlohr Bueso &lt;davidlohr@hp.com&gt;
Signed-off-by: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Anton Blanchard &lt;anton@samba.org&gt;
Cc: Aurelien Jacquiot &lt;a-jacquiot@ti.com&gt;
Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: Bharat Bhushan &lt;r65777@freescale.com&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Chen Liqin &lt;liqin.linux@gmail.com&gt;
Cc: Chris Metcalf &lt;cmetcalf@tilera.com&gt;
Cc: Christian Borntraeger &lt;borntraeger@de.ibm.com&gt;
Cc: Chris Zankel &lt;chris@zankel.net&gt;
Cc: David Howells &lt;dhowells@redhat.com&gt;
Cc: David S. Miller &lt;davem@davemloft.net&gt;
Cc: Deepthi Dharwar &lt;deepthi@linux.vnet.ibm.com&gt;
Cc: Dominik Dingel &lt;dingel@linux.vnet.ibm.com&gt;
Cc: Fenghua Yu &lt;fenghua.yu@intel.com&gt;
Cc: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Cc: Guan Xuetao &lt;gxt@mprc.pku.edu.cn&gt;
Cc: Haavard Skinnemoen &lt;hskinnemoen@gmail.com&gt;
Cc: Hans-Christian Egtvedt &lt;egtvedt@samfundet.no&gt;
Cc: Heiko Carstens &lt;heiko.carstens@de.ibm.com&gt;
Cc: Helge Deller &lt;deller@gmx.de&gt;
Cc: Hirokazu Takata &lt;takata@linux-m32r.org&gt;
Cc: Ivan Kokshaysky &lt;ink@jurassic.park.msu.ru&gt;
Cc: James E.J. Bottomley &lt;jejb@parisc-linux.org&gt;
Cc: James Hogan &lt;james.hogan@imgtec.com&gt;
Cc: Jason Wang &lt;jasowang@redhat.com&gt;
Cc: Jesper Nilsson &lt;jesper.nilsson@axis.com&gt;
Cc: Joe Perches &lt;joe@perches.com&gt;
Cc: Jonas Bonn &lt;jonas@southpole.se&gt;
Cc: Joseph Myers &lt;joseph@codesourcery.com&gt;
Cc: Kees Cook &lt;keescook@chromium.org&gt;
Cc: Koichi Yasutake &lt;yasutake.koichi@jp.panasonic.com&gt;
Cc: Lennox Wu &lt;lennox.wu@gmail.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Mark Salter &lt;msalter@redhat.com&gt;
Cc: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
Cc: Matt Turner &lt;mattst88@gmail.com&gt;
Cc: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
Cc: Michael Neuling &lt;mikey@neuling.org&gt;
Cc: Michal Simek &lt;monstr@monstr.eu&gt;
Cc: Mikael Starvik &lt;starvik@axis.com&gt;
Cc: Nicolas Pitre &lt;nico@linaro.org&gt;
Cc: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Cc: Paul Burton &lt;paul.burton@imgtec.com&gt;
Cc: Paul E. McKenney &lt;paulmck@linux.vnet.ibm.com&gt;
Cc: Paul Gortmaker &lt;paul.gortmaker@windriver.com&gt;
Cc: Paul Mackerras &lt;paulus@samba.org&gt;
Cc: Qais Yousef &lt;qais.yousef@imgtec.com&gt;
Cc: Qiaowei Ren &lt;qiaowei.ren@intel.com&gt;
Cc: Rafael Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Cc: Ralf Baechle &lt;ralf@linux-mips.org&gt;
Cc: Richard Henderson &lt;rth@twiddle.net&gt;
Cc: Richard Kuo &lt;rkuo@codeaurora.org&gt;
Cc: Russell King &lt;linux@arm.linux.org.uk&gt;
Cc: Steven Miao &lt;realmz6@gmail.com&gt;
Cc: Steven Rostedt &lt;srostedt@redhat.com&gt;
Cc: Stratos Karafotis &lt;stratosk@semaphore.gr&gt;
Cc: Tim Chen &lt;tim.c.chen@linux.intel.com&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Cc: Vasily Kulikov &lt;segoon@openwall.com&gt;
Cc: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Cc: Vineet Gupta &lt;Vineet.Gupta1@synopsys.com&gt;
Cc: Waiman Long &lt;Waiman.Long@hp.com&gt;
Cc: Will Deacon &lt;will.deacon@arm.com&gt;
Cc: Wolfram Sang &lt;wsa@the-dreams.de&gt;
Cc: adi-buildroot-devel@lists.sourceforge.net
Cc: linux390@de.ibm.com
Cc: linux-alpha@vger.kernel.org
Cc: linux-am33-list@redhat.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-c6x-dev@linux-c6x.org
Cc: linux-cris-kernel@axis.com
Cc: linux-hexagon@vger.kernel.org
Cc: linux-ia64@vger.kernel.org
Cc: linux@lists.openrisc.net
Cc: linux-m32r-ja@ml.linux-m32r.org
Cc: linux-m32r@ml.linux-m32r.org
Cc: linux-m68k@lists.linux-m68k.org
Cc: linux-metag@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: linux-xtensa@linux-xtensa.org
Cc: sparclinux@vger.kernel.org
Link: http://lkml.kernel.org/r/1404079773.2619.4.camel@buesod1.americas.hpqcorp.net
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
</pre>
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