<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/arch/Kconfig, branch linux-4.7.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>Clarify naming of thread info/stack allocators</title>
<updated>2016-06-24T22:09:37+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2016-06-24T22:09:37+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b235beea9e996a4d36fed6cfef4801a3e7d7a9a5'/>
<id>b235beea9e996a4d36fed6cfef4801a3e7d7a9a5</id>
<content type='text'>
We've had the thread info allocated together with the thread stack for
most architectures for a long time (since the thread_info was split off
from the task struct), but that is about to change.

But the patches that move the thread info to be off-stack (and a part of
the task struct instead) made it clear how confused the allocator and
freeing functions are.

Because the common case was that we share an allocation with the thread
stack and the thread_info, the two pointers were identical.  That
identity then meant that we would have things like

	ti = alloc_thread_info_node(tsk, node);
	...
	tsk-&gt;stack = ti;

which certainly _worked_ (since stack and thread_info have the same
value), but is rather confusing: why are we assigning a thread_info to
the stack? And if we move the thread_info away, the "confusing" code
just gets to be entirely bogus.

So remove all this confusion, and make it clear that we are doing the
stack allocation by renaming and clarifying the function names to be
about the stack.  The fact that the thread_info then shares the
allocation is an implementation detail, and not really about the
allocation itself.

This is a pure renaming and type fix: we pass in the same pointer, it's
just that we clarify what the pointer means.

The ia64 code that actually only has one single allocation (for all of
task_struct, thread_info and kernel thread stack) now looks a bit odd,
but since "tsk-&gt;stack" is actually not even used there, that oddity
doesn't matter.  It would be a separate thing to clean that up, I
intentionally left the ia64 changes as a pure brute-force renaming and
type change.

Acked-by: Andy Lutomirski &lt;luto@amacapital.net&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>
We've had the thread info allocated together with the thread stack for
most architectures for a long time (since the thread_info was split off
from the task struct), but that is about to change.

But the patches that move the thread info to be off-stack (and a part of
the task struct instead) made it clear how confused the allocator and
freeing functions are.

Because the common case was that we share an allocation with the thread
stack and the thread_info, the two pointers were identical.  That
identity then meant that we would have things like

	ti = alloc_thread_info_node(tsk, node);
	...
	tsk-&gt;stack = ti;

which certainly _worked_ (since stack and thread_info have the same
value), but is rather confusing: why are we assigning a thread_info to
the stack? And if we move the thread_info away, the "confusing" code
just gets to be entirely bogus.

So remove all this confusion, and make it clear that we are doing the
stack allocation by renaming and clarifying the function names to be
about the stack.  The fact that the thread_info then shares the
allocation is an implementation detail, and not really about the
allocation itself.

This is a pure renaming and type fix: we pass in the same pointer, it's
just that we clarify what the pointer means.

The ia64 code that actually only has one single allocation (for all of
task_struct, thread_info and kernel thread stack) now looks a bit odd,
but since "tsk-&gt;stack" is actually not even used there, that oddity
doesn't matter.  It would be a separate thing to clean that up, I
intentionally left the ia64 changes as a pure brute-force renaming and
type change.

Acked-by: Andy Lutomirski &lt;luto@amacapital.net&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>isa: Allow ISA-style drivers on modern systems</title>
<updated>2016-06-18T03:21:12+00:00</updated>
<author>
<name>William Breathitt Gray</name>
<email>vilhelm.gray@gmail.com</email>
</author>
<published>2016-05-27T22:08:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=3a4955111ad46a022f05b51f91306d864f989625'/>
<id>3a4955111ad46a022f05b51f91306d864f989625</id>
<content type='text'>
Several modern devices, such as PC/104 cards, are expected to run on
modern systems via an ISA bus interface. Since ISA is a legacy interface
for most modern architectures, ISA support should remain disabled in
general. Support for ISA-style drivers should be enabled on a per driver
basis.

To allow ISA-style drivers on modern systems, this patch introduces the
ISA_BUS_API and ISA_BUS Kconfig options. The ISA bus driver will now
build conditionally on the ISA_BUS_API Kconfig option, which defaults to
the legacy ISA Kconfig option. The ISA_BUS Kconfig option allows the
ISA_BUS_API Kconfig option to be selected on architectures which do not
enable ISA (e.g. X86_64).

The ISA_BUS Kconfig option is currently only implemented for X86
architectures. Other architectures may have their own ISA_BUS Kconfig
options added as required.

Reviewed-by: Guenter Roeck &lt;linux@roeck-us.net&gt;
Signed-off-by: William Breathitt Gray &lt;vilhelm.gray@gmail.com&gt;
Acked-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Several modern devices, such as PC/104 cards, are expected to run on
modern systems via an ISA bus interface. Since ISA is a legacy interface
for most modern architectures, ISA support should remain disabled in
general. Support for ISA-style drivers should be enabled on a per driver
basis.

To allow ISA-style drivers on modern systems, this patch introduces the
ISA_BUS_API and ISA_BUS Kconfig options. The ISA bus driver will now
build conditionally on the ISA_BUS_API Kconfig option, which defaults to
the legacy ISA Kconfig option. The ISA_BUS Kconfig option allows the
ISA_BUS_API Kconfig option to be selected on architectures which do not
enable ISA (e.g. X86_64).

The ISA_BUS Kconfig option is currently only implemented for X86
architectures. Other architectures may have their own ISA_BUS Kconfig
options added as required.

Reviewed-by: Guenter Roeck &lt;linux@roeck-us.net&gt;
Signed-off-by: William Breathitt Gray &lt;vilhelm.gray@gmail.com&gt;
Acked-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'hash' of git://ftp.sciencehorizons.net/linux</title>
<updated>2016-05-28T23:15:25+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2016-05-28T23:15:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7e0fb73c52c4037b4d5ef9ff56c7296a3151bd92'/>
<id>7e0fb73c52c4037b4d5ef9ff56c7296a3151bd92</id>
<content type='text'>
Pull string hash improvements from George Spelvin:
 "This series does several related things:

   - Makes the dcache hash (fs/namei.c) useful for general kernel use.

     (Thanks to Bruce for noticing the zero-length corner case)

   - Converts the string hashes in &lt;linux/sunrpc/svcauth.h&gt; to use the
     above.

   - Avoids 64-bit multiplies in hash_64() on 32-bit platforms.  Two
     32-bit multiplies will do well enough.

   - Rids the world of the bad hash multipliers in hash_32.

     This finishes the job started in commit 689de1d6ca95 ("Minimal
     fix-up of bad hashing behavior of hash_64()")

     The vast majority of Linux architectures have hardware support for
     32x32-bit multiply and so derive no benefit from "simplified"
     multipliers.

     The few processors that do not (68000, h8/300 and some models of
     Microblaze) have arch-specific implementations added.  Those
     patches are last in the series.

   - Overhauls the dcache hash mixing.

     The patch in commit 0fed3ac866ea ("namei: Improve hash mixing if
     CONFIG_DCACHE_WORD_ACCESS") was an off-the-cuff suggestion.
     Replaced with a much more careful design that's simultaneously
     faster and better.  (My own invention, as there was noting suitable
     in the literature I could find.  Comments welcome!)

   - Modify the hash_name() loop to skip the initial HASH_MIX().  This
     would let us salt the hash if we ever wanted to.

   - Sort out partial_name_hash().

     The hash function is declared as using a long state, even though
     it's truncated to 32 bits at the end and the extra internal state
     contributes nothing to the result.  And some callers do odd things:

      - fs/hfs/string.c only allocates 32 bits of state
      - fs/hfsplus/unicode.c uses it to hash 16-bit unicode symbols not bytes

   - Modify bytemask_from_count to handle inputs of 1..sizeof(long)
     rather than 0..sizeof(long)-1.  This would simplify users other
     than full_name_hash"

  Special thanks to Bruce Fields for testing and finding bugs in v1.  (I
  learned some humbling lessons about "obviously correct" code.)

  On the arch-specific front, the m68k assembly has been tested in a
  standalone test harness, I've been in contact with the Microblaze
  maintainers who mostly don't care, as the hardware multiplier is never
  omitted in real-world applications, and I haven't heard anything from
  the H8/300 world"

* 'hash' of git://ftp.sciencehorizons.net/linux:
  h8300: Add &lt;asm/hash.h&gt;
  microblaze: Add &lt;asm/hash.h&gt;
  m68k: Add &lt;asm/hash.h&gt;
  &lt;linux/hash.h&gt;: Add support for architecture-specific functions
  fs/namei.c: Improve dcache hash function
  Eliminate bad hash multipliers from hash_32() and  hash_64()
  Change hash_64() return value to 32 bits
  &lt;linux/sunrpc/svcauth.h&gt;: Define hash_str() in terms of hashlen_string()
  fs/namei.c: Add hashlen_string() function
  Pull out string hash to &lt;linux/stringhash.h&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull string hash improvements from George Spelvin:
 "This series does several related things:

   - Makes the dcache hash (fs/namei.c) useful for general kernel use.

     (Thanks to Bruce for noticing the zero-length corner case)

   - Converts the string hashes in &lt;linux/sunrpc/svcauth.h&gt; to use the
     above.

   - Avoids 64-bit multiplies in hash_64() on 32-bit platforms.  Two
     32-bit multiplies will do well enough.

   - Rids the world of the bad hash multipliers in hash_32.

     This finishes the job started in commit 689de1d6ca95 ("Minimal
     fix-up of bad hashing behavior of hash_64()")

     The vast majority of Linux architectures have hardware support for
     32x32-bit multiply and so derive no benefit from "simplified"
     multipliers.

     The few processors that do not (68000, h8/300 and some models of
     Microblaze) have arch-specific implementations added.  Those
     patches are last in the series.

   - Overhauls the dcache hash mixing.

     The patch in commit 0fed3ac866ea ("namei: Improve hash mixing if
     CONFIG_DCACHE_WORD_ACCESS") was an off-the-cuff suggestion.
     Replaced with a much more careful design that's simultaneously
     faster and better.  (My own invention, as there was noting suitable
     in the literature I could find.  Comments welcome!)

   - Modify the hash_name() loop to skip the initial HASH_MIX().  This
     would let us salt the hash if we ever wanted to.

   - Sort out partial_name_hash().

     The hash function is declared as using a long state, even though
     it's truncated to 32 bits at the end and the extra internal state
     contributes nothing to the result.  And some callers do odd things:

      - fs/hfs/string.c only allocates 32 bits of state
      - fs/hfsplus/unicode.c uses it to hash 16-bit unicode symbols not bytes

   - Modify bytemask_from_count to handle inputs of 1..sizeof(long)
     rather than 0..sizeof(long)-1.  This would simplify users other
     than full_name_hash"

  Special thanks to Bruce Fields for testing and finding bugs in v1.  (I
  learned some humbling lessons about "obviously correct" code.)

  On the arch-specific front, the m68k assembly has been tested in a
  standalone test harness, I've been in contact with the Microblaze
  maintainers who mostly don't care, as the hardware multiplier is never
  omitted in real-world applications, and I haven't heard anything from
  the H8/300 world"

* 'hash' of git://ftp.sciencehorizons.net/linux:
  h8300: Add &lt;asm/hash.h&gt;
  microblaze: Add &lt;asm/hash.h&gt;
  m68k: Add &lt;asm/hash.h&gt;
  &lt;linux/hash.h&gt;: Add support for architecture-specific functions
  fs/namei.c: Improve dcache hash function
  Eliminate bad hash multipliers from hash_32() and  hash_64()
  Change hash_64() return value to 32 bits
  &lt;linux/sunrpc/svcauth.h&gt;: Define hash_str() in terms of hashlen_string()
  fs/namei.c: Add hashlen_string() function
  Pull out string hash to &lt;linux/stringhash.h&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>&lt;linux/hash.h&gt;: Add support for architecture-specific functions</title>
<updated>2016-05-28T19:48:31+00:00</updated>
<author>
<name>George Spelvin</name>
<email>linux@sciencehorizons.net</email>
</author>
<published>2016-05-27T02:11:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=468a9428521e7d00fb21250af363eb94dc1d6861'/>
<id>468a9428521e7d00fb21250af363eb94dc1d6861</id>
<content type='text'>
This is just the infrastructure; there are no users yet.

This is modelled on CONFIG_ARCH_RANDOM; a CONFIG_ symbol declares
the existence of &lt;asm/hash.h&gt;.

That file may define its own versions of various functions, and define
HAVE_* symbols (no CONFIG_ prefix!) to suppress the generic ones.

Included is a self-test (in lib/test_hash.c) that verifies the basics.
It is NOT in general required that the arch-specific functions compute
the same thing as the generic, but if a HAVE_* symbol is defined with
the value 1, then equality is tested.

Signed-off-by: George Spelvin &lt;linux@sciencehorizons.net&gt;
Cc: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Cc: Greg Ungerer &lt;gerg@linux-m68k.org&gt;
Cc: Andreas Schwab &lt;schwab@linux-m68k.org&gt;
Cc: Philippe De Muyter &lt;phdm@macq.eu&gt;
Cc: linux-m68k@lists.linux-m68k.org
Cc: Alistair Francis &lt;alistai@xilinx.com&gt;
Cc: Michal Simek &lt;michal.simek@xilinx.com&gt;
Cc: Yoshinori Sato &lt;ysato@users.sourceforge.jp&gt;
Cc: uclinux-h8-devel@lists.sourceforge.jp
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This is just the infrastructure; there are no users yet.

This is modelled on CONFIG_ARCH_RANDOM; a CONFIG_ symbol declares
the existence of &lt;asm/hash.h&gt;.

That file may define its own versions of various functions, and define
HAVE_* symbols (no CONFIG_ prefix!) to suppress the generic ones.

Included is a self-test (in lib/test_hash.c) that verifies the basics.
It is NOT in general required that the arch-specific functions compute
the same thing as the generic, but if a HAVE_* symbol is defined with
the value 1, then equality is tested.

Signed-off-by: George Spelvin &lt;linux@sciencehorizons.net&gt;
Cc: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Cc: Greg Ungerer &lt;gerg@linux-m68k.org&gt;
Cc: Andreas Schwab &lt;schwab@linux-m68k.org&gt;
Cc: Philippe De Muyter &lt;phdm@macq.eu&gt;
Cc: linux-m68k@lists.linux-m68k.org
Cc: Alistair Francis &lt;alistai@xilinx.com&gt;
Cc: Michal Simek &lt;michal.simek@xilinx.com&gt;
Cc: Yoshinori Sato &lt;ysato@users.sourceforge.jp&gt;
Cc: uclinux-h8-devel@lists.sourceforge.jp
</pre>
</div>
</content>
</entry>
<entry>
<title>lib/GCD.c: use binary GCD algorithm instead of Euclidean</title>
<updated>2016-05-21T00:58:30+00:00</updated>
<author>
<name>Zhaoxiu Zeng</name>
<email>zhaoxiu.zeng@gmail.com</email>
</author>
<published>2016-05-21T00:03:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=fff7fb0b2d908dec779783d8eaf3d7725230f75e'/>
<id>fff7fb0b2d908dec779783d8eaf3d7725230f75e</id>
<content type='text'>
The binary GCD algorithm is based on the following facts:
	1. If a and b are all evens, then gcd(a,b) = 2 * gcd(a/2, b/2)
	2. If a is even and b is odd, then gcd(a,b) = gcd(a/2, b)
	3. If a and b are all odds, then gcd(a,b) = gcd((a-b)/2, b) = gcd((a+b)/2, b)

Even on x86 machines with reasonable division hardware, the binary
algorithm runs about 25% faster (80% the execution time) than the
division-based Euclidian algorithm.

On platforms like Alpha and ARMv6 where division is a function call to
emulation code, it's even more significant.

There are two variants of the code here, depending on whether a fast
__ffs (find least significant set bit) instruction is available.  This
allows the unpredictable branches in the bit-at-a-time shifting loop to
be eliminated.

If fast __ffs is not available, the "even/odd" GCD variant is used.

I use the following code to benchmark:

	#include &lt;stdio.h&gt;
	#include &lt;stdlib.h&gt;
	#include &lt;stdint.h&gt;
	#include &lt;string.h&gt;
	#include &lt;time.h&gt;
	#include &lt;unistd.h&gt;

	#define swap(a, b) \
		do { \
			a ^= b; \
			b ^= a; \
			a ^= b; \
		} while (0)

	unsigned long gcd0(unsigned long a, unsigned long b)
	{
		unsigned long r;

		if (a &lt; b) {
			swap(a, b);
		}

		if (b == 0)
			return a;

		while ((r = a % b) != 0) {
			a = b;
			b = r;
		}

		return b;
	}

	unsigned long gcd1(unsigned long a, unsigned long b)
	{
		unsigned long r = a | b;

		if (!a || !b)
			return r;

		b &gt;&gt;= __builtin_ctzl(b);

		for (;;) {
			a &gt;&gt;= __builtin_ctzl(a);
			if (a == b)
				return a &lt;&lt; __builtin_ctzl(r);

			if (a &lt; b)
				swap(a, b);
			a -= b;
		}
	}

	unsigned long gcd2(unsigned long a, unsigned long b)
	{
		unsigned long r = a | b;

		if (!a || !b)
			return r;

		r &amp;= -r;

		while (!(b &amp; r))
			b &gt;&gt;= 1;

		for (;;) {
			while (!(a &amp; r))
				a &gt;&gt;= 1;
			if (a == b)
				return a;

			if (a &lt; b)
				swap(a, b);
			a -= b;
			a &gt;&gt;= 1;
			if (a &amp; r)
				a += b;
			a &gt;&gt;= 1;
		}
	}

	unsigned long gcd3(unsigned long a, unsigned long b)
	{
		unsigned long r = a | b;

		if (!a || !b)
			return r;

		b &gt;&gt;= __builtin_ctzl(b);
		if (b == 1)
			return r &amp; -r;

		for (;;) {
			a &gt;&gt;= __builtin_ctzl(a);
			if (a == 1)
				return r &amp; -r;
			if (a == b)
				return a &lt;&lt; __builtin_ctzl(r);

			if (a &lt; b)
				swap(a, b);
			a -= b;
		}
	}

	unsigned long gcd4(unsigned long a, unsigned long b)
	{
		unsigned long r = a | b;

		if (!a || !b)
			return r;

		r &amp;= -r;

		while (!(b &amp; r))
			b &gt;&gt;= 1;
		if (b == r)
			return r;

		for (;;) {
			while (!(a &amp; r))
				a &gt;&gt;= 1;
			if (a == r)
				return r;
			if (a == b)
				return a;

			if (a &lt; b)
				swap(a, b);
			a -= b;
			a &gt;&gt;= 1;
			if (a &amp; r)
				a += b;
			a &gt;&gt;= 1;
		}
	}

	static unsigned long (*gcd_func[])(unsigned long a, unsigned long b) = {
		gcd0, gcd1, gcd2, gcd3, gcd4,
	};

	#define TEST_ENTRIES (sizeof(gcd_func) / sizeof(gcd_func[0]))

	#if defined(__x86_64__)

	#define rdtscll(val) do { \
		unsigned long __a,__d; \
		__asm__ __volatile__("rdtsc" : "=a" (__a), "=d" (__d)); \
		(val) = ((unsigned long long)__a) | (((unsigned long long)__d)&lt;&lt;32); \
	} while(0)

	static unsigned long long benchmark_gcd_func(unsigned long (*gcd)(unsigned long, unsigned long),
								unsigned long a, unsigned long b, unsigned long *res)
	{
		unsigned long long start, end;
		unsigned long long ret;
		unsigned long gcd_res;

		rdtscll(start);
		gcd_res = gcd(a, b);
		rdtscll(end);

		if (end &gt;= start)
			ret = end - start;
		else
			ret = ~0ULL - start + 1 + end;

		*res = gcd_res;
		return ret;
	}

	#else

	static inline struct timespec read_time(void)
	{
		struct timespec time;
		clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &amp;time);
		return time;
	}

	static inline unsigned long long diff_time(struct timespec start, struct timespec end)
	{
		struct timespec temp;

		if ((end.tv_nsec - start.tv_nsec) &lt; 0) {
			temp.tv_sec = end.tv_sec - start.tv_sec - 1;
			temp.tv_nsec = 1000000000ULL + end.tv_nsec - start.tv_nsec;
		} else {
			temp.tv_sec = end.tv_sec - start.tv_sec;
			temp.tv_nsec = end.tv_nsec - start.tv_nsec;
		}

		return temp.tv_sec * 1000000000ULL + temp.tv_nsec;
	}

	static unsigned long long benchmark_gcd_func(unsigned long (*gcd)(unsigned long, unsigned long),
								unsigned long a, unsigned long b, unsigned long *res)
	{
		struct timespec start, end;
		unsigned long gcd_res;

		start = read_time();
		gcd_res = gcd(a, b);
		end = read_time();

		*res = gcd_res;
		return diff_time(start, end);
	}

	#endif

	static inline unsigned long get_rand()
	{
		if (sizeof(long) == 8)
			return (unsigned long)rand() &lt;&lt; 32 | rand();
		else
			return rand();
	}

	int main(int argc, char **argv)
	{
		unsigned int seed = time(0);
		int loops = 100;
		int repeats = 1000;
		unsigned long (*res)[TEST_ENTRIES];
		unsigned long long elapsed[TEST_ENTRIES];
		int i, j, k;

		for (;;) {
			int opt = getopt(argc, argv, "n:r:s:");
			/* End condition always first */
			if (opt == -1)
				break;

			switch (opt) {
			case 'n':
				loops = atoi(optarg);
				break;
			case 'r':
				repeats = atoi(optarg);
				break;
			case 's':
				seed = strtoul(optarg, NULL, 10);
				break;
			default:
				/* You won't actually get here. */
				break;
			}
		}

		res = malloc(sizeof(unsigned long) * TEST_ENTRIES * loops);
		memset(elapsed, 0, sizeof(elapsed));

		srand(seed);
		for (j = 0; j &lt; loops; j++) {
			unsigned long a = get_rand();
			/* Do we have args? */
			unsigned long b = argc &gt; optind ? strtoul(argv[optind], NULL, 10) : get_rand();
			unsigned long long min_elapsed[TEST_ENTRIES];
			for (k = 0; k &lt; repeats; k++) {
				for (i = 0; i &lt; TEST_ENTRIES; i++) {
					unsigned long long tmp = benchmark_gcd_func(gcd_func[i], a, b, &amp;res[j][i]);
					if (k == 0 || min_elapsed[i] &gt; tmp)
						min_elapsed[i] = tmp;
				}
			}
			for (i = 0; i &lt; TEST_ENTRIES; i++)
				elapsed[i] += min_elapsed[i];
		}

		for (i = 0; i &lt; TEST_ENTRIES; i++)
			printf("gcd%d: elapsed %llu\n", i, elapsed[i]);

		k = 0;
		srand(seed);
		for (j = 0; j &lt; loops; j++) {
			unsigned long a = get_rand();
			unsigned long b = argc &gt; optind ? strtoul(argv[optind], NULL, 10) : get_rand();
			for (i = 1; i &lt; TEST_ENTRIES; i++) {
				if (res[j][i] != res[j][0])
					break;
			}
			if (i &lt; TEST_ENTRIES) {
				if (k == 0) {
					k = 1;
					fprintf(stderr, "Error:\n");
				}
				fprintf(stderr, "gcd(%lu, %lu): ", a, b);
				for (i = 0; i &lt; TEST_ENTRIES; i++)
					fprintf(stderr, "%ld%s", res[j][i], i &lt; TEST_ENTRIES - 1 ? ", " : "\n");
			}
		}

		if (k == 0)
			fprintf(stderr, "PASS\n");

		free(res);

		return 0;
	}

Compiled with "-O2", on "VirtualBox 4.4.0-22-generic #38-Ubuntu x86_64" got:

  zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10
  gcd0: elapsed 10174
  gcd1: elapsed 2120
  gcd2: elapsed 2902
  gcd3: elapsed 2039
  gcd4: elapsed 2812
  PASS
  zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10
  gcd0: elapsed 9309
  gcd1: elapsed 2280
  gcd2: elapsed 2822
  gcd3: elapsed 2217
  gcd4: elapsed 2710
  PASS
  zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10
  gcd0: elapsed 9589
  gcd1: elapsed 2098
  gcd2: elapsed 2815
  gcd3: elapsed 2030
  gcd4: elapsed 2718
  PASS
  zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10
  gcd0: elapsed 9914
  gcd1: elapsed 2309
  gcd2: elapsed 2779
  gcd3: elapsed 2228
  gcd4: elapsed 2709
  PASS

[akpm@linux-foundation.org: avoid #defining a CONFIG_ variable]
Signed-off-by: Zhaoxiu Zeng &lt;zhaoxiu.zeng@gmail.com&gt;
Signed-off-by: George Spelvin &lt;linux@horizon.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>
The binary GCD algorithm is based on the following facts:
	1. If a and b are all evens, then gcd(a,b) = 2 * gcd(a/2, b/2)
	2. If a is even and b is odd, then gcd(a,b) = gcd(a/2, b)
	3. If a and b are all odds, then gcd(a,b) = gcd((a-b)/2, b) = gcd((a+b)/2, b)

Even on x86 machines with reasonable division hardware, the binary
algorithm runs about 25% faster (80% the execution time) than the
division-based Euclidian algorithm.

On platforms like Alpha and ARMv6 where division is a function call to
emulation code, it's even more significant.

There are two variants of the code here, depending on whether a fast
__ffs (find least significant set bit) instruction is available.  This
allows the unpredictable branches in the bit-at-a-time shifting loop to
be eliminated.

If fast __ffs is not available, the "even/odd" GCD variant is used.

I use the following code to benchmark:

	#include &lt;stdio.h&gt;
	#include &lt;stdlib.h&gt;
	#include &lt;stdint.h&gt;
	#include &lt;string.h&gt;
	#include &lt;time.h&gt;
	#include &lt;unistd.h&gt;

	#define swap(a, b) \
		do { \
			a ^= b; \
			b ^= a; \
			a ^= b; \
		} while (0)

	unsigned long gcd0(unsigned long a, unsigned long b)
	{
		unsigned long r;

		if (a &lt; b) {
			swap(a, b);
		}

		if (b == 0)
			return a;

		while ((r = a % b) != 0) {
			a = b;
			b = r;
		}

		return b;
	}

	unsigned long gcd1(unsigned long a, unsigned long b)
	{
		unsigned long r = a | b;

		if (!a || !b)
			return r;

		b &gt;&gt;= __builtin_ctzl(b);

		for (;;) {
			a &gt;&gt;= __builtin_ctzl(a);
			if (a == b)
				return a &lt;&lt; __builtin_ctzl(r);

			if (a &lt; b)
				swap(a, b);
			a -= b;
		}
	}

	unsigned long gcd2(unsigned long a, unsigned long b)
	{
		unsigned long r = a | b;

		if (!a || !b)
			return r;

		r &amp;= -r;

		while (!(b &amp; r))
			b &gt;&gt;= 1;

		for (;;) {
			while (!(a &amp; r))
				a &gt;&gt;= 1;
			if (a == b)
				return a;

			if (a &lt; b)
				swap(a, b);
			a -= b;
			a &gt;&gt;= 1;
			if (a &amp; r)
				a += b;
			a &gt;&gt;= 1;
		}
	}

	unsigned long gcd3(unsigned long a, unsigned long b)
	{
		unsigned long r = a | b;

		if (!a || !b)
			return r;

		b &gt;&gt;= __builtin_ctzl(b);
		if (b == 1)
			return r &amp; -r;

		for (;;) {
			a &gt;&gt;= __builtin_ctzl(a);
			if (a == 1)
				return r &amp; -r;
			if (a == b)
				return a &lt;&lt; __builtin_ctzl(r);

			if (a &lt; b)
				swap(a, b);
			a -= b;
		}
	}

	unsigned long gcd4(unsigned long a, unsigned long b)
	{
		unsigned long r = a | b;

		if (!a || !b)
			return r;

		r &amp;= -r;

		while (!(b &amp; r))
			b &gt;&gt;= 1;
		if (b == r)
			return r;

		for (;;) {
			while (!(a &amp; r))
				a &gt;&gt;= 1;
			if (a == r)
				return r;
			if (a == b)
				return a;

			if (a &lt; b)
				swap(a, b);
			a -= b;
			a &gt;&gt;= 1;
			if (a &amp; r)
				a += b;
			a &gt;&gt;= 1;
		}
	}

	static unsigned long (*gcd_func[])(unsigned long a, unsigned long b) = {
		gcd0, gcd1, gcd2, gcd3, gcd4,
	};

	#define TEST_ENTRIES (sizeof(gcd_func) / sizeof(gcd_func[0]))

	#if defined(__x86_64__)

	#define rdtscll(val) do { \
		unsigned long __a,__d; \
		__asm__ __volatile__("rdtsc" : "=a" (__a), "=d" (__d)); \
		(val) = ((unsigned long long)__a) | (((unsigned long long)__d)&lt;&lt;32); \
	} while(0)

	static unsigned long long benchmark_gcd_func(unsigned long (*gcd)(unsigned long, unsigned long),
								unsigned long a, unsigned long b, unsigned long *res)
	{
		unsigned long long start, end;
		unsigned long long ret;
		unsigned long gcd_res;

		rdtscll(start);
		gcd_res = gcd(a, b);
		rdtscll(end);

		if (end &gt;= start)
			ret = end - start;
		else
			ret = ~0ULL - start + 1 + end;

		*res = gcd_res;
		return ret;
	}

	#else

	static inline struct timespec read_time(void)
	{
		struct timespec time;
		clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &amp;time);
		return time;
	}

	static inline unsigned long long diff_time(struct timespec start, struct timespec end)
	{
		struct timespec temp;

		if ((end.tv_nsec - start.tv_nsec) &lt; 0) {
			temp.tv_sec = end.tv_sec - start.tv_sec - 1;
			temp.tv_nsec = 1000000000ULL + end.tv_nsec - start.tv_nsec;
		} else {
			temp.tv_sec = end.tv_sec - start.tv_sec;
			temp.tv_nsec = end.tv_nsec - start.tv_nsec;
		}

		return temp.tv_sec * 1000000000ULL + temp.tv_nsec;
	}

	static unsigned long long benchmark_gcd_func(unsigned long (*gcd)(unsigned long, unsigned long),
								unsigned long a, unsigned long b, unsigned long *res)
	{
		struct timespec start, end;
		unsigned long gcd_res;

		start = read_time();
		gcd_res = gcd(a, b);
		end = read_time();

		*res = gcd_res;
		return diff_time(start, end);
	}

	#endif

	static inline unsigned long get_rand()
	{
		if (sizeof(long) == 8)
			return (unsigned long)rand() &lt;&lt; 32 | rand();
		else
			return rand();
	}

	int main(int argc, char **argv)
	{
		unsigned int seed = time(0);
		int loops = 100;
		int repeats = 1000;
		unsigned long (*res)[TEST_ENTRIES];
		unsigned long long elapsed[TEST_ENTRIES];
		int i, j, k;

		for (;;) {
			int opt = getopt(argc, argv, "n:r:s:");
			/* End condition always first */
			if (opt == -1)
				break;

			switch (opt) {
			case 'n':
				loops = atoi(optarg);
				break;
			case 'r':
				repeats = atoi(optarg);
				break;
			case 's':
				seed = strtoul(optarg, NULL, 10);
				break;
			default:
				/* You won't actually get here. */
				break;
			}
		}

		res = malloc(sizeof(unsigned long) * TEST_ENTRIES * loops);
		memset(elapsed, 0, sizeof(elapsed));

		srand(seed);
		for (j = 0; j &lt; loops; j++) {
			unsigned long a = get_rand();
			/* Do we have args? */
			unsigned long b = argc &gt; optind ? strtoul(argv[optind], NULL, 10) : get_rand();
			unsigned long long min_elapsed[TEST_ENTRIES];
			for (k = 0; k &lt; repeats; k++) {
				for (i = 0; i &lt; TEST_ENTRIES; i++) {
					unsigned long long tmp = benchmark_gcd_func(gcd_func[i], a, b, &amp;res[j][i]);
					if (k == 0 || min_elapsed[i] &gt; tmp)
						min_elapsed[i] = tmp;
				}
			}
			for (i = 0; i &lt; TEST_ENTRIES; i++)
				elapsed[i] += min_elapsed[i];
		}

		for (i = 0; i &lt; TEST_ENTRIES; i++)
			printf("gcd%d: elapsed %llu\n", i, elapsed[i]);

		k = 0;
		srand(seed);
		for (j = 0; j &lt; loops; j++) {
			unsigned long a = get_rand();
			unsigned long b = argc &gt; optind ? strtoul(argv[optind], NULL, 10) : get_rand();
			for (i = 1; i &lt; TEST_ENTRIES; i++) {
				if (res[j][i] != res[j][0])
					break;
			}
			if (i &lt; TEST_ENTRIES) {
				if (k == 0) {
					k = 1;
					fprintf(stderr, "Error:\n");
				}
				fprintf(stderr, "gcd(%lu, %lu): ", a, b);
				for (i = 0; i &lt; TEST_ENTRIES; i++)
					fprintf(stderr, "%ld%s", res[j][i], i &lt; TEST_ENTRIES - 1 ? ", " : "\n");
			}
		}

		if (k == 0)
			fprintf(stderr, "PASS\n");

		free(res);

		return 0;
	}

Compiled with "-O2", on "VirtualBox 4.4.0-22-generic #38-Ubuntu x86_64" got:

  zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10
  gcd0: elapsed 10174
  gcd1: elapsed 2120
  gcd2: elapsed 2902
  gcd3: elapsed 2039
  gcd4: elapsed 2812
  PASS
  zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10
  gcd0: elapsed 9309
  gcd1: elapsed 2280
  gcd2: elapsed 2822
  gcd3: elapsed 2217
  gcd4: elapsed 2710
  PASS
  zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10
  gcd0: elapsed 9589
  gcd1: elapsed 2098
  gcd2: elapsed 2815
  gcd3: elapsed 2030
  gcd4: elapsed 2718
  PASS
  zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10
  gcd0: elapsed 9914
  gcd1: elapsed 2309
  gcd2: elapsed 2779
  gcd3: elapsed 2228
  gcd4: elapsed 2709
  PASS

[akpm@linux-foundation.org: avoid #defining a CONFIG_ variable]
Signed-off-by: Zhaoxiu Zeng &lt;zhaoxiu.zeng@gmail.com&gt;
Signed-off-by: George Spelvin &lt;linux@horizon.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>printk/nmi: generic solution for safe printk in NMI</title>
<updated>2016-05-21T00:58:30+00:00</updated>
<author>
<name>Petr Mladek</name>
<email>pmladek@suse.com</email>
</author>
<published>2016-05-21T00:00:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=42a0bb3f71383b457a7db362f1c69e7afb96732b'/>
<id>42a0bb3f71383b457a7db362f1c69e7afb96732b</id>
<content type='text'>
printk() takes some locks and could not be used a safe way in NMI
context.

The chance of a deadlock is real especially when printing stacks from
all CPUs.  This particular problem has been addressed on x86 by the
commit a9edc8809328 ("x86/nmi: Perform a safe NMI stack trace on all
CPUs").

The patchset brings two big advantages.  First, it makes the NMI
backtraces safe on all architectures for free.  Second, it makes all NMI
messages almost safe on all architectures (the temporary buffer is
limited.  We still should keep the number of messages in NMI context at
minimum).

Note that there already are several messages printed in NMI context:
WARN_ON(in_nmi()), BUG_ON(in_nmi()), anything being printed out from MCE
handlers.  These are not easy to avoid.

This patch reuses most of the code and makes it generic.  It is useful
for all messages and architectures that support NMI.

The alternative printk_func is set when entering and is reseted when
leaving NMI context.  It queues IRQ work to copy the messages into the
main ring buffer in a safe context.

__printk_nmi_flush() copies all available messages and reset the buffer.
Then we could use a simple cmpxchg operations to get synchronized with
writers.  There is also used a spinlock to get synchronized with other
flushers.

We do not longer use seq_buf because it depends on external lock.  It
would be hard to make all supported operations safe for a lockless use.
It would be confusing and error prone to make only some operations safe.

The code is put into separate printk/nmi.c as suggested by Steven
Rostedt.  It needs a per-CPU buffer and is compiled only on
architectures that call nmi_enter().  This is achieved by the new
HAVE_NMI Kconfig flag.

The are MN10300 and Xtensa architectures.  We need to clean up NMI
handling there first.  Let's do it separately.

The patch is heavily based on the draft from Peter Zijlstra, see

  https://lkml.org/lkml/2015/6/10/327

[arnd@arndb.de: printk-nmi: use %zu format string for size_t]
[akpm@linux-foundation.org: min_t-&gt;min - all types are size_t here]
Signed-off-by: Petr Mladek &lt;pmladek@suse.com&gt;
Suggested-by: Peter Zijlstra &lt;peterz@infradead.org&gt;
Suggested-by: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Cc: Jan Kara &lt;jack@suse.cz&gt;
Acked-by: Russell King &lt;rmk+kernel@arm.linux.org.uk&gt;	[arm part]
Cc: Daniel Thompson &lt;daniel.thompson@linaro.org&gt;
Cc: Jiri Kosina &lt;jkosina@suse.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Ralf Baechle &lt;ralf@linux-mips.org&gt;
Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
Cc: David Miller &lt;davem@davemloft.net&gt;
Cc: Daniel Thompson &lt;daniel.thompson@linaro.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>
printk() takes some locks and could not be used a safe way in NMI
context.

The chance of a deadlock is real especially when printing stacks from
all CPUs.  This particular problem has been addressed on x86 by the
commit a9edc8809328 ("x86/nmi: Perform a safe NMI stack trace on all
CPUs").

The patchset brings two big advantages.  First, it makes the NMI
backtraces safe on all architectures for free.  Second, it makes all NMI
messages almost safe on all architectures (the temporary buffer is
limited.  We still should keep the number of messages in NMI context at
minimum).

Note that there already are several messages printed in NMI context:
WARN_ON(in_nmi()), BUG_ON(in_nmi()), anything being printed out from MCE
handlers.  These are not easy to avoid.

This patch reuses most of the code and makes it generic.  It is useful
for all messages and architectures that support NMI.

The alternative printk_func is set when entering and is reseted when
leaving NMI context.  It queues IRQ work to copy the messages into the
main ring buffer in a safe context.

__printk_nmi_flush() copies all available messages and reset the buffer.
Then we could use a simple cmpxchg operations to get synchronized with
writers.  There is also used a spinlock to get synchronized with other
flushers.

We do not longer use seq_buf because it depends on external lock.  It
would be hard to make all supported operations safe for a lockless use.
It would be confusing and error prone to make only some operations safe.

The code is put into separate printk/nmi.c as suggested by Steven
Rostedt.  It needs a per-CPU buffer and is compiled only on
architectures that call nmi_enter().  This is achieved by the new
HAVE_NMI Kconfig flag.

The are MN10300 and Xtensa architectures.  We need to clean up NMI
handling there first.  Let's do it separately.

The patch is heavily based on the draft from Peter Zijlstra, see

  https://lkml.org/lkml/2015/6/10/327

[arnd@arndb.de: printk-nmi: use %zu format string for size_t]
[akpm@linux-foundation.org: min_t-&gt;min - all types are size_t here]
Signed-off-by: Petr Mladek &lt;pmladek@suse.com&gt;
Suggested-by: Peter Zijlstra &lt;peterz@infradead.org&gt;
Suggested-by: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Cc: Jan Kara &lt;jack@suse.cz&gt;
Acked-by: Russell King &lt;rmk+kernel@arm.linux.org.uk&gt;	[arm part]
Cc: Daniel Thompson &lt;daniel.thompson@linaro.org&gt;
Cc: Jiri Kosina &lt;jkosina@suse.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Ralf Baechle &lt;ralf@linux-mips.org&gt;
Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
Cc: David Miller &lt;davem@davemloft.net&gt;
Cc: Daniel Thompson &lt;daniel.thompson@linaro.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>exit_thread: remove empty bodies</title>
<updated>2016-05-21T00:58:30+00:00</updated>
<author>
<name>Jiri Slaby</name>
<email>jslaby@suse.cz</email>
</author>
<published>2016-05-21T00:00:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5f56a5dfdb9bcb3bca03df59980d4d2f012cbb53'/>
<id>5f56a5dfdb9bcb3bca03df59980d4d2f012cbb53</id>
<content type='text'>
Define HAVE_EXIT_THREAD for archs which want to do something in
exit_thread. For others, let's define exit_thread as an empty inline.

This is a cleanup before we change the prototype of exit_thread to
accept a task parameter.

[akpm@linux-foundation.org: fix mips]
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: "H. Peter Anvin" &lt;hpa@zytor.com&gt;
Cc: "James E.J. Bottomley" &lt;jejb@parisc-linux.org&gt;
Cc: Aurelien Jacquiot &lt;a-jacquiot@ti.com&gt;
Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Chen Liqin &lt;liqin.linux@gmail.com&gt;
Cc: Chris Metcalf &lt;cmetcalf@mellanox.com&gt;
Cc: Chris Zankel &lt;chris@zankel.net&gt;
Cc: David Howells &lt;dhowells@redhat.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: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Ivan Kokshaysky &lt;ink@jurassic.park.msu.ru&gt;
Cc: James Hogan &lt;james.hogan@imgtec.com&gt;
Cc: Jeff Dike &lt;jdike@addtoit.com&gt;
Cc: Jesper Nilsson &lt;jesper.nilsson@axis.com&gt;
Cc: Jiri Slaby &lt;jslaby@suse.cz&gt;
Cc: Jonas Bonn &lt;jonas@southpole.se&gt;
Cc: Koichi Yasutake &lt;yasutake.koichi@jp.panasonic.com&gt;
Cc: Lennox Wu &lt;lennox.wu@gmail.com&gt;
Cc: Ley Foon Tan &lt;lftan@altera.com&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 Ellerman &lt;mpe@ellerman.id.au&gt;
Cc: Michal Simek &lt;monstr@monstr.eu&gt;
Cc: Mikael Starvik &lt;starvik@axis.com&gt;
Cc: Paul Mackerras &lt;paulus@samba.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Ralf Baechle &lt;ralf@linux-mips.org&gt;
Cc: Rich Felker &lt;dalias@libc.org&gt;
Cc: Richard Henderson &lt;rth@twiddle.net&gt;
Cc: Richard Kuo &lt;rkuo@codeaurora.org&gt;
Cc: Richard Weinberger &lt;richard@nod.at&gt;
Cc: Russell King &lt;linux@arm.linux.org.uk&gt;
Cc: Steven Miao &lt;realmz6@gmail.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Cc: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Cc: Will Deacon &lt;will.deacon@arm.com&gt;
Cc: Yoshinori Sato &lt;ysato@users.sourceforge.jp&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>
Define HAVE_EXIT_THREAD for archs which want to do something in
exit_thread. For others, let's define exit_thread as an empty inline.

This is a cleanup before we change the prototype of exit_thread to
accept a task parameter.

[akpm@linux-foundation.org: fix mips]
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: "H. Peter Anvin" &lt;hpa@zytor.com&gt;
Cc: "James E.J. Bottomley" &lt;jejb@parisc-linux.org&gt;
Cc: Aurelien Jacquiot &lt;a-jacquiot@ti.com&gt;
Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Chen Liqin &lt;liqin.linux@gmail.com&gt;
Cc: Chris Metcalf &lt;cmetcalf@mellanox.com&gt;
Cc: Chris Zankel &lt;chris@zankel.net&gt;
Cc: David Howells &lt;dhowells@redhat.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: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Ivan Kokshaysky &lt;ink@jurassic.park.msu.ru&gt;
Cc: James Hogan &lt;james.hogan@imgtec.com&gt;
Cc: Jeff Dike &lt;jdike@addtoit.com&gt;
Cc: Jesper Nilsson &lt;jesper.nilsson@axis.com&gt;
Cc: Jiri Slaby &lt;jslaby@suse.cz&gt;
Cc: Jonas Bonn &lt;jonas@southpole.se&gt;
Cc: Koichi Yasutake &lt;yasutake.koichi@jp.panasonic.com&gt;
Cc: Lennox Wu &lt;lennox.wu@gmail.com&gt;
Cc: Ley Foon Tan &lt;lftan@altera.com&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 Ellerman &lt;mpe@ellerman.id.au&gt;
Cc: Michal Simek &lt;monstr@monstr.eu&gt;
Cc: Mikael Starvik &lt;starvik@axis.com&gt;
Cc: Paul Mackerras &lt;paulus@samba.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Ralf Baechle &lt;ralf@linux-mips.org&gt;
Cc: Rich Felker &lt;dalias@libc.org&gt;
Cc: Richard Henderson &lt;rth@twiddle.net&gt;
Cc: Richard Kuo &lt;rkuo@codeaurora.org&gt;
Cc: Richard Weinberger &lt;richard@nod.at&gt;
Cc: Russell King &lt;linux@arm.linux.org.uk&gt;
Cc: Steven Miao &lt;realmz6@gmail.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Cc: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Cc: Will Deacon &lt;will.deacon@arm.com&gt;
Cc: Yoshinori Sato &lt;ysato@users.sourceforge.jp&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>objtool: Add CONFIG_STACK_VALIDATION option</title>
<updated>2016-02-29T07:35:13+00:00</updated>
<author>
<name>Josh Poimboeuf</name>
<email>jpoimboe@redhat.com</email>
</author>
<published>2016-02-29T04:22:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b9ab5ebb14ec389bd80f66613f1fe3f8f65f2521'/>
<id>b9ab5ebb14ec389bd80f66613f1fe3f8f65f2521</id>
<content type='text'>
Add a CONFIG_STACK_VALIDATION option which will run "objtool check" for
each .o file to ensure the validity of its stack metadata.

Signed-off-by: Josh Poimboeuf &lt;jpoimboe@redhat.com&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Andy Lutomirski &lt;luto@kernel.org&gt;
Cc: Arnaldo Carvalho de Melo &lt;acme@kernel.org&gt;
Cc: Bernd Petrovitsch &lt;bernd@petrovitsch.priv.at&gt;
Cc: Borislav Petkov &lt;bp@alien8.de&gt;
Cc: Chris J Arges &lt;chris.j.arges@canonical.com&gt;
Cc: Jiri Slaby &lt;jslaby@suse.cz&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Michal Marek &lt;mmarek@suse.cz&gt;
Cc: Namhyung Kim &lt;namhyung@gmail.com&gt;
Cc: Pedro Alves &lt;palves@redhat.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/92baab69a6bf9bc7043af0bfca9fb964a1d45546.1456719558.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add a CONFIG_STACK_VALIDATION option which will run "objtool check" for
each .o file to ensure the validity of its stack metadata.

Signed-off-by: Josh Poimboeuf &lt;jpoimboe@redhat.com&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Andy Lutomirski &lt;luto@kernel.org&gt;
Cc: Arnaldo Carvalho de Melo &lt;acme@kernel.org&gt;
Cc: Bernd Petrovitsch &lt;bernd@petrovitsch.priv.at&gt;
Cc: Borislav Petkov &lt;bp@alien8.de&gt;
Cc: Chris J Arges &lt;chris.j.arges@canonical.com&gt;
Cc: Jiri Slaby &lt;jslaby@suse.cz&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Michal Marek &lt;mmarek@suse.cz&gt;
Cc: Namhyung Kim &lt;namhyung@gmail.com&gt;
Cc: Pedro Alves &lt;palves@redhat.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/92baab69a6bf9bc7043af0bfca9fb964a1d45546.1456719558.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>dma-mapping: always provide the dma_map_ops based implementation</title>
<updated>2016-01-21T01:09:18+00:00</updated>
<author>
<name>Christoph Hellwig</name>
<email>hch@lst.de</email>
</author>
<published>2016-01-20T23:02:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e1c7e324539ada3b2b13ca2898bcb4948a9ef9db'/>
<id>e1c7e324539ada3b2b13ca2898bcb4948a9ef9db</id>
<content type='text'>
Move the generic implementation to &lt;linux/dma-mapping.h&gt; now that all
architectures support it and remove the HAVE_DMA_ATTR Kconfig symbol now
that everyone supports them.

[valentinrothberg@gmail.com: remove leftovers in Kconfig]
Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: Aurelien Jacquiot &lt;a-jacquiot@ti.com&gt;
Cc: Chris Metcalf &lt;cmetcalf@ezchip.com&gt;
Cc: David Howells &lt;dhowells@redhat.com&gt;
Cc: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Cc: Haavard Skinnemoen &lt;hskinnemoen@gmail.com&gt;
Cc: Hans-Christian Egtvedt &lt;egtvedt@samfundet.no&gt;
Cc: Helge Deller &lt;deller@gmx.de&gt;
Cc: James Hogan &lt;james.hogan@imgtec.com&gt;
Cc: Jesper Nilsson &lt;jesper.nilsson@axis.com&gt;
Cc: Koichi Yasutake &lt;yasutake.koichi@jp.panasonic.com&gt;
Cc: Ley Foon Tan &lt;lftan@altera.com&gt;
Cc: Mark Salter &lt;msalter@redhat.com&gt;
Cc: Mikael Starvik &lt;starvik@axis.com&gt;
Cc: Steven Miao &lt;realmz6@gmail.com&gt;
Cc: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Cc: Christian Borntraeger &lt;borntraeger@de.ibm.com&gt;
Cc: Joerg Roedel &lt;jroedel@suse.de&gt;
Cc: Sebastian Ott &lt;sebott@linux.vnet.ibm.com&gt;
Signed-off-by: Valentin Rothberg &lt;valentinrothberg@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>
Move the generic implementation to &lt;linux/dma-mapping.h&gt; now that all
architectures support it and remove the HAVE_DMA_ATTR Kconfig symbol now
that everyone supports them.

[valentinrothberg@gmail.com: remove leftovers in Kconfig]
Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: Aurelien Jacquiot &lt;a-jacquiot@ti.com&gt;
Cc: Chris Metcalf &lt;cmetcalf@ezchip.com&gt;
Cc: David Howells &lt;dhowells@redhat.com&gt;
Cc: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Cc: Haavard Skinnemoen &lt;hskinnemoen@gmail.com&gt;
Cc: Hans-Christian Egtvedt &lt;egtvedt@samfundet.no&gt;
Cc: Helge Deller &lt;deller@gmx.de&gt;
Cc: James Hogan &lt;james.hogan@imgtec.com&gt;
Cc: Jesper Nilsson &lt;jesper.nilsson@axis.com&gt;
Cc: Koichi Yasutake &lt;yasutake.koichi@jp.panasonic.com&gt;
Cc: Ley Foon Tan &lt;lftan@altera.com&gt;
Cc: Mark Salter &lt;msalter@redhat.com&gt;
Cc: Mikael Starvik &lt;starvik@axis.com&gt;
Cc: Steven Miao &lt;realmz6@gmail.com&gt;
Cc: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Cc: Christian Borntraeger &lt;borntraeger@de.ibm.com&gt;
Cc: Joerg Roedel &lt;jroedel@suse.de&gt;
Cc: Sebastian Ott &lt;sebott@linux.vnet.ibm.com&gt;
Signed-off-by: Valentin Rothberg &lt;valentinrothberg@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>dma-mapping: make the generic coherent dma mmap implementation optional</title>
<updated>2016-01-21T01:09:18+00:00</updated>
<author>
<name>Christoph Hellwig</name>
<email>hch@lst.de</email>
</author>
<published>2016-01-20T23:01:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0d4a619b64bad7117947a84a10c17a2b8f14d252'/>
<id>0d4a619b64bad7117947a84a10c17a2b8f14d252</id>
<content type='text'>
This series converts all remaining architectures to use dma_map_ops and
the generic implementation of the DMA API.  This not only simplifies the
code a lot, but also prepares for possible future changes like more
generic non-iommu dma_ops implementations or generic per-device
dma_map_ops.

This patch (of 16):

We have a couple architectures that do not want to support this code, so
add another Kconfig symbol that disables the code similar to what we do
for the nommu case.

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Haavard Skinnemoen &lt;hskinnemoen@gmail.com&gt;
Cc: Hans-Christian Egtvedt &lt;egtvedt@samfundet.no&gt;
Cc: Steven Miao &lt;realmz6@gmail.com&gt;
Cc: Ley Foon Tan &lt;lftan@altera.com&gt;
Cc: David Howells &lt;dhowells@redhat.com&gt;
Cc: Koichi Yasutake &lt;yasutake.koichi@jp.panasonic.com&gt;
Cc: Chris Metcalf &lt;cmetcalf@ezchip.com&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: Aurelien Jacquiot &lt;a-jacquiot@ti.com&gt;
Cc: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Cc: Helge Deller &lt;deller@gmx.de&gt;
Cc: James Hogan &lt;james.hogan@imgtec.com&gt;
Cc: Jesper Nilsson &lt;jesper.nilsson@axis.com&gt;
Cc: Mark Salter &lt;msalter@redhat.com&gt;
Cc: Mikael Starvik &lt;starvik@axis.com&gt;
Cc: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Cc: Christian Borntraeger &lt;borntraeger@de.ibm.com&gt;
Cc: Joerg Roedel &lt;jroedel@suse.de&gt;
Cc: Sebastian Ott &lt;sebott@linux.vnet.ibm.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>
This series converts all remaining architectures to use dma_map_ops and
the generic implementation of the DMA API.  This not only simplifies the
code a lot, but also prepares for possible future changes like more
generic non-iommu dma_ops implementations or generic per-device
dma_map_ops.

This patch (of 16):

We have a couple architectures that do not want to support this code, so
add another Kconfig symbol that disables the code similar to what we do
for the nommu case.

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Haavard Skinnemoen &lt;hskinnemoen@gmail.com&gt;
Cc: Hans-Christian Egtvedt &lt;egtvedt@samfundet.no&gt;
Cc: Steven Miao &lt;realmz6@gmail.com&gt;
Cc: Ley Foon Tan &lt;lftan@altera.com&gt;
Cc: David Howells &lt;dhowells@redhat.com&gt;
Cc: Koichi Yasutake &lt;yasutake.koichi@jp.panasonic.com&gt;
Cc: Chris Metcalf &lt;cmetcalf@ezchip.com&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: Aurelien Jacquiot &lt;a-jacquiot@ti.com&gt;
Cc: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Cc: Helge Deller &lt;deller@gmx.de&gt;
Cc: James Hogan &lt;james.hogan@imgtec.com&gt;
Cc: Jesper Nilsson &lt;jesper.nilsson@axis.com&gt;
Cc: Mark Salter &lt;msalter@redhat.com&gt;
Cc: Mikael Starvik &lt;starvik@axis.com&gt;
Cc: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Cc: Christian Borntraeger &lt;borntraeger@de.ibm.com&gt;
Cc: Joerg Roedel &lt;jroedel@suse.de&gt;
Cc: Sebastian Ott &lt;sebott@linux.vnet.ibm.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>
</feed>
