<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/arch/arc/include, branch v3.16.75</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>ARC: mm: allow mprotect to make stack mappings executable</title>
<updated>2018-11-20T18:05:39+00:00</updated>
<author>
<name>Vineet Gupta</name>
<email>vgupta@synopsys.com</email>
</author>
<published>2018-07-11T17:42:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2387ae5715a7393f0e2830fd0969e1d86b378492'/>
<id>2387ae5715a7393f0e2830fd0969e1d86b378492</id>
<content type='text'>
commit 93312b6da4df31e4102ce5420e6217135a16c7ea upstream.

mprotect(EXEC) was failing for stack mappings as default vm flags was
missing MAYEXEC.

This was triggered by glibc test suite nptl/tst-execstack testcase

What is surprising is that despite running LTP for years on, we didn't
catch this issue as it lacks a directed test case.

gcc dejagnu tests with nested functions also requiring exec stack work
fine though because they rely on the GNU_STACK segment spit out by
compiler and handled in kernel elf loader.

This glibc case is different as the stack is non exec to begin with and
a dlopen of shared lib with GNU_STACK segment triggers the exec stack
proceedings using a mprotect(PROT_EXEC) which was broken.

Signed-off-by: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 93312b6da4df31e4102ce5420e6217135a16c7ea upstream.

mprotect(EXEC) was failing for stack mappings as default vm flags was
missing MAYEXEC.

This was triggered by glibc test suite nptl/tst-execstack testcase

What is surprising is that despite running LTP for years on, we didn't
catch this issue as it lacks a directed test case.

gcc dejagnu tests with nested functions also requiring exec stack work
fine though because they rely on the GNU_STACK segment spit out by
compiler and handled in kernel elf loader.

This glibc case is different as the stack is non exec to begin with and
a dlopen of shared lib with GNU_STACK segment triggers the exec stack
proceedings using a mprotect(PROT_EXEC) which was broken.

Signed-off-by: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ARC: Fix CONFIG_SWAP</title>
<updated>2018-11-20T18:05:38+00:00</updated>
<author>
<name>Alexey Brodkin</name>
<email>abrodkin@synopsys.com</email>
</author>
<published>2018-06-28T23:59:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a3e56ccf2a07017c11d24db19f9d03930c28ebed'/>
<id>a3e56ccf2a07017c11d24db19f9d03930c28ebed</id>
<content type='text'>
commit 6e3761145a9ba3ce267c330b6bff51cf6a057b06 upstream.

swap was broken on ARC due to silly copy-paste issue.

We encode offset from swapcache page in __swp_entry() as (off &lt;&lt; 13) but
were not decoding back in __swp_offset() as (off &gt;&gt; 13) - it was still
(off &lt;&lt; 13).

This finally fixes swap usage on ARC.

| # mkswap /dev/sda2
|
| # swapon -a -e /dev/sda2
| Adding 500728k swap on /dev/sda2.  Priority:-2 extents:1 across:500728k
|
| # free
|              total       used       free     shared    buffers     cached
| Mem:        765104      13456     751648       4736          8       4736
| -/+ buffers/cache:       8712     756392
| Swap:       500728          0     500728

Signed-off-by: Alexey Brodkin &lt;abrodkin@synopsys.com&gt;
Signed-off-by: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 6e3761145a9ba3ce267c330b6bff51cf6a057b06 upstream.

swap was broken on ARC due to silly copy-paste issue.

We encode offset from swapcache page in __swp_entry() as (off &lt;&lt; 13) but
were not decoding back in __swp_offset() as (off &gt;&gt; 13) - it was still
(off &lt;&lt; 13).

This finally fixes swap usage on ARC.

| # mkswap /dev/sda2
|
| # swapon -a -e /dev/sda2
| Adding 500728k swap on /dev/sda2.  Priority:-2 extents:1 across:500728k
|
| # free
|              total       used       free     shared    buffers     cached
| Mem:        765104      13456     751648       4736          8       4736
| -/+ buffers/cache:       8712     756392
| Swap:       500728          0     500728

Signed-off-by: Alexey Brodkin &lt;abrodkin@synopsys.com&gt;
Signed-off-by: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Make asm/word-at-a-time.h available on all architectures</title>
<updated>2018-10-21T07:46:11+00:00</updated>
<author>
<name>Chris Metcalf</name>
<email>cmetcalf@ezchip.com</email>
</author>
<published>2015-04-29T16:48:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a45cee23a3cba600f23e14daeabbe9a50fd0ecde'/>
<id>a45cee23a3cba600f23e14daeabbe9a50fd0ecde</id>
<content type='text'>
commit a6e2f029ae34f41adb6ae3812c32c5d326e1abd2 upstream.

Added the x86 implementation of word-at-a-time to the
generic version, which previously only supported big-endian.

Omitted the x86-specific load_unaligned_zeropad(), which in
any case is also not present for the existing BE-only
implementation of a word-at-a-time, and is only used under
CONFIG_DCACHE_WORD_ACCESS.

Added as a "generic-y" to the Kbuilds of all architectures
that didn't previously have it.

Signed-off-by: Chris Metcalf &lt;cmetcalf@ezchip.com&gt;
[bwh: Backported to 3.16:
 - Drop change in arch/nios2
 - Adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit a6e2f029ae34f41adb6ae3812c32c5d326e1abd2 upstream.

Added the x86 implementation of word-at-a-time to the
generic version, which previously only supported big-endian.

Omitted the x86-specific load_unaligned_zeropad(), which in
any case is also not present for the existing BE-only
implementation of a word-at-a-time, and is only used under
CONFIG_DCACHE_WORD_ACCESS.

Added as a "generic-y" to the Kbuilds of all architectures
that didn't previously have it.

Signed-off-by: Chris Metcalf &lt;cmetcalf@ezchip.com&gt;
[bwh: Backported to 3.16:
 - Drop change in arch/nios2
 - Adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arc: drop _PAGE_FILE and pte_file()-related helpers</title>
<updated>2018-10-03T03:09:53+00:00</updated>
<author>
<name>Kirill A. Shutemov</name>
<email>kirill.shutemov@linux.intel.com</email>
</author>
<published>2015-02-10T22:10:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5445c123757a283a090c29367bb6a5e478ab7f15'/>
<id>5445c123757a283a090c29367bb6a5e478ab7f15</id>
<content type='text'>
commit 18747151308f9e0fb63766057957617ec4afa190 upstream.

We've replaced remap_file_pages(2) implementation with emulation.  Nobody
creates non-linear mapping anymore.

Signed-off-by: Kirill A. Shutemov &lt;kirill.shutemov@linux.intel.com&gt;
Acked-by: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 18747151308f9e0fb63766057957617ec4afa190 upstream.

We've replaced remap_file_pages(2) implementation with emulation.  Nobody
creates non-linear mapping anymore.

Signed-off-by: Kirill A. Shutemov &lt;kirill.shutemov@linux.intel.com&gt;
Acked-by: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ARC: uaccess: get_user to zero out dest in cause of fault</title>
<updated>2016-11-20T01:17:27+00:00</updated>
<author>
<name>Vineet Gupta</name>
<email>Vineet.Gupta1@synopsys.com</email>
</author>
<published>2016-08-19T19:10:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b9f780045b42b37270d6b7980bd95814a606a389'/>
<id>b9f780045b42b37270d6b7980bd95814a606a389</id>
<content type='text'>
commit 05d9d0b96e53c52a113fd783c0c97c830c8dc7af upstream.

Al reported potential issue with ARC get_user() as it wasn't clearing
out destination pointer in case of fault due to bad address etc.

Verified using following

| {
|  	u32 bogus1 = 0xdeadbeef;
|	u64 bogus2 = 0xdead;
|	int rc1, rc2;
|
|  	pr_info("Orig values %x %llx\n", bogus1, bogus2);
|	rc1 = get_user(bogus1, (u32 __user *)0x40000000);
|	rc2 = get_user(bogus2, (u64 __user *)0x50000000);
|	pr_info("access %d %d, new values %x %llx\n",
|		rc1, rc2, bogus1, bogus2);
| }

| [ARCLinux]# insmod /mnt/kernel-module/qtn.ko
| Orig values deadbeef dead
| access -14 -14, new values 0 0

Reported-by: Al Viro &lt;viro@ZenIV.linux.org.uk&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: linux-snps-arc@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 05d9d0b96e53c52a113fd783c0c97c830c8dc7af upstream.

Al reported potential issue with ARC get_user() as it wasn't clearing
out destination pointer in case of fault due to bad address etc.

Verified using following

| {
|  	u32 bogus1 = 0xdeadbeef;
|	u64 bogus2 = 0xdead;
|	int rc1, rc2;
|
|  	pr_info("Orig values %x %llx\n", bogus1, bogus2);
|	rc1 = get_user(bogus1, (u32 __user *)0x40000000);
|	rc2 = get_user(bogus2, (u64 __user *)0x50000000);
|	pr_info("access %d %d, new values %x %llx\n",
|		rc1, rc2, bogus1, bogus2);
| }

| [ARCLinux]# insmod /mnt/kernel-module/qtn.ko
| Orig values deadbeef dead
| access -14 -14, new values 0 0

Reported-by: Al Viro &lt;viro@ZenIV.linux.org.uk&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: linux-snps-arc@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ARC: Call trace_hardirqs_on() before enabling irqs</title>
<updated>2016-11-20T01:17:08+00:00</updated>
<author>
<name>Daniel Mentz</name>
<email>danielmentz@google.com</email>
</author>
<published>2016-08-05T00:56:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=80da58faaedb7f3d63721d32e7e079af074e516a'/>
<id>80da58faaedb7f3d63721d32e7e079af074e516a</id>
<content type='text'>
commit 18b43e89d295cc65151c505c643c98fb2c320e59 upstream.

trace_hardirqs_on_caller() in lockdep.c expects to be called before, not
after interrupts are actually enabled.

The following comment in kernel/locking/lockdep.c substantiates this
claim:

"
/*
 * We're enabling irqs and according to our state above irqs weren't
 * already enabled, yet we find the hardware thinks they are in fact
 * enabled.. someone messed up their IRQ state tracing.
 */
"

An example can be found in include/linux/irqflags.h:

	do { trace_hardirqs_on(); raw_local_irq_enable(); } while (0)

Without this change, we hit the following DEBUG_LOCKS_WARN_ON.

[    7.760000] ------------[ cut here ]------------
[    7.760000] WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:2711 resume_user_mode_begin+0x48/0xf0
[    7.770000] DEBUG_LOCKS_WARN_ON(!irqs_disabled())
[    7.780000] Modules linked in:
[    7.780000] CPU: 0 PID: 1 Comm: init Not tainted 4.7.0-00003-gc668bb9-dirty #366
[    7.790000]
[    7.790000] Stack Trace:
[    7.790000]   arc_unwind_core.constprop.1+0xa4/0x118
[    7.800000]   warn_slowpath_fmt+0x72/0x158
[    7.800000]   resume_user_mode_begin+0x48/0xf0
[    7.810000] ---[ end trace 6f6a7a8fae20d2f0 ]---

Signed-off-by: Daniel Mentz &lt;danielmentz@google.com&gt;
Signed-off-by: Vineet Gupta &lt;vgupta@synopsys.com&gt;
[bwh: Backported to 3.16: adjust filename]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 18b43e89d295cc65151c505c643c98fb2c320e59 upstream.

trace_hardirqs_on_caller() in lockdep.c expects to be called before, not
after interrupts are actually enabled.

The following comment in kernel/locking/lockdep.c substantiates this
claim:

"
/*
 * We're enabling irqs and according to our state above irqs weren't
 * already enabled, yet we find the hardware thinks they are in fact
 * enabled.. someone messed up their IRQ state tracing.
 */
"

An example can be found in include/linux/irqflags.h:

	do { trace_hardirqs_on(); raw_local_irq_enable(); } while (0)

Without this change, we hit the following DEBUG_LOCKS_WARN_ON.

[    7.760000] ------------[ cut here ]------------
[    7.760000] WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:2711 resume_user_mode_begin+0x48/0xf0
[    7.770000] DEBUG_LOCKS_WARN_ON(!irqs_disabled())
[    7.780000] Modules linked in:
[    7.780000] CPU: 0 PID: 1 Comm: init Not tainted 4.7.0-00003-gc668bb9-dirty #366
[    7.790000]
[    7.790000] Stack Trace:
[    7.790000]   arc_unwind_core.constprop.1+0xa4/0x118
[    7.800000]   warn_slowpath_fmt+0x72/0x158
[    7.800000]   resume_user_mode_begin+0x48/0xf0
[    7.810000] ---[ end trace 6f6a7a8fae20d2f0 ]---

Signed-off-by: Daniel Mentz &lt;danielmentz@google.com&gt;
Signed-off-by: Vineet Gupta &lt;vgupta@synopsys.com&gt;
[bwh: Backported to 3.16: adjust filename]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ARC: unbork !LLSC build</title>
<updated>2016-06-15T20:29:35+00:00</updated>
<author>
<name>Vineet Gupta</name>
<email>vgupta@synopsys.com</email>
</author>
<published>2015-05-10T06:34:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=df929b25c8f7519a3e30eb8948d1e6e933c762d4'/>
<id>df929b25c8f7519a3e30eb8948d1e6e933c762d4</id>
<content type='text'>
commit daaf40e53b5dbdf75255d58a45ce8ac65ca511a8 upstream.

Fixes: f7d11e93ee97a locking,arch,arc: Fold atomic_ops
Signed-off-by: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Cc: Guenter Roeck &lt;linux@roeck-us.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit daaf40e53b5dbdf75255d58a45ce8ac65ca511a8 upstream.

Fixes: f7d11e93ee97a locking,arch,arc: Fold atomic_ops
Signed-off-by: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Cc: Guenter Roeck &lt;linux@roeck-us.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ARC: dw2 unwind: Reinstante unwinding out of modules</title>
<updated>2016-01-25T10:43:40+00:00</updated>
<author>
<name>Vineet Gupta</name>
<email>vgupta@synopsys.com</email>
</author>
<published>2015-12-11T12:34:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b05a4fbe9bde47084e333cae6035536e7ceb9f14'/>
<id>b05a4fbe9bde47084e333cae6035536e7ceb9f14</id>
<content type='text'>
commit bc79c9a7216562a2035d2f64f73626613c1300d0 upstream.

The fix which removed linear searching of dwarf (because binary lookup
data always exists) missed out on the fact that modules don't get the
binary lookup tables info. This caused unwinding out of modules to stop
working.

So add binary lookup header setup (equivalent of eh_frame_hdr setup) to
modules as well.

While at it, confine the header setup to within unwinder code,
reducing one API exposed out of unwinder code.

Fixes: 2e22502c080f ARC: dw2 unwind: Remove falllback linear search thru FDE entries
Signed-off-by: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Signed-off-by: Luis Henriques &lt;luis.henriques@canonical.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit bc79c9a7216562a2035d2f64f73626613c1300d0 upstream.

The fix which removed linear searching of dwarf (because binary lookup
data always exists) missed out on the fact that modules don't get the
binary lookup tables info. This caused unwinding out of modules to stop
working.

So add binary lookup header setup (equivalent of eh_frame_hdr setup) to
modules as well.

While at it, confine the header setup to within unwinder code,
reducing one API exposed out of unwinder code.

Fixes: 2e22502c080f ARC: dw2 unwind: Remove falllback linear search thru FDE entries
Signed-off-by: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Signed-off-by: Luis Henriques &lt;luis.henriques@canonical.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ARC: make sure instruction_pointer() returns unsigned value</title>
<updated>2015-08-10T08:54:19+00:00</updated>
<author>
<name>Alexey Brodkin</name>
<email>abrodkin@synopsys.com</email>
</author>
<published>2015-07-13T07:25:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c7bc79956a634da40b323e3cf71650a3c08cecd3'/>
<id>c7bc79956a634da40b323e3cf71650a3c08cecd3</id>
<content type='text'>
commit f51e2f1911122879eefefa4c592dea8bf794b39c upstream.

Currently instruction_pointer() returns pt_regs-&gt;ret and so return value
is of type "long", which implicitly stands for "signed long".

While that's perfectly fine when dealing with 32-bit values if return
value of instruction_pointer() gets assigned to 64-bit variable sign
extension may happen.

And at least in one real use-case it happens already.
In perf_prepare_sample() return value of perf_instruction_pointer()
(which is an alias to instruction_pointer() in case of ARC) is assigned
to (struct perf_sample_data)-&gt;ip (which type is "u64").

And what we see if instuction pointer points to user-space application
that in case of ARC lays below 0x8000_0000 "ip" gets set properly with
leading 32 zeros. But if instruction pointer points to kernel address
space that starts from 0x8000_0000 then "ip" is set with 32 leadig
"f"-s. I.e. id instruction_pointer() returns 0x8100_0000, "ip" will be
assigned with 0xffff_ffff__8100_0000. Which is obviously wrong.

In particular that issuse broke output of perf, because perf was unable
to associate addresses like 0xffff_ffff__8100_0000 with anything from
/proc/kallsyms.

That's what we used to see:
 -----------&gt;8----------
  6.27%  ls       [unknown]                [k] 0xffffffff8046c5cc
  2.96%  ls       libuClibc-0.9.34-git.so  [.] memcpy
  2.25%  ls       libuClibc-0.9.34-git.so  [.] memset
  1.66%  ls       [unknown]                [k] 0xffffffff80666536
  1.54%  ls       libuClibc-0.9.34-git.so  [.] 0x000224d6
  1.18%  ls       libuClibc-0.9.34-git.so  [.] 0x00022472
 -----------&gt;8----------

With that change perf output looks much better now:
 -----------&gt;8----------
  8.21%  ls       [kernel.kallsyms]        [k] memset
  3.52%  ls       libuClibc-0.9.34-git.so  [.] memcpy
  2.11%  ls       libuClibc-0.9.34-git.so  [.] malloc
  1.88%  ls       libuClibc-0.9.34-git.so  [.] memset
  1.64%  ls       [kernel.kallsyms]        [k] _raw_spin_unlock_irqrestore
  1.41%  ls       [kernel.kallsyms]        [k] __d_lookup_rcu
 -----------&gt;8----------

Signed-off-by: Alexey Brodkin &lt;abrodkin@synopsys.com&gt;
Cc: arc-linux-dev@synopsys.com
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Signed-off-by: Luis Henriques &lt;luis.henriques@canonical.com&gt;
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commit f51e2f1911122879eefefa4c592dea8bf794b39c upstream.

Currently instruction_pointer() returns pt_regs-&gt;ret and so return value
is of type "long", which implicitly stands for "signed long".

While that's perfectly fine when dealing with 32-bit values if return
value of instruction_pointer() gets assigned to 64-bit variable sign
extension may happen.

And at least in one real use-case it happens already.
In perf_prepare_sample() return value of perf_instruction_pointer()
(which is an alias to instruction_pointer() in case of ARC) is assigned
to (struct perf_sample_data)-&gt;ip (which type is "u64").

And what we see if instuction pointer points to user-space application
that in case of ARC lays below 0x8000_0000 "ip" gets set properly with
leading 32 zeros. But if instruction pointer points to kernel address
space that starts from 0x8000_0000 then "ip" is set with 32 leadig
"f"-s. I.e. id instruction_pointer() returns 0x8100_0000, "ip" will be
assigned with 0xffff_ffff__8100_0000. Which is obviously wrong.

In particular that issuse broke output of perf, because perf was unable
to associate addresses like 0xffff_ffff__8100_0000 with anything from
/proc/kallsyms.

That's what we used to see:
 -----------&gt;8----------
  6.27%  ls       [unknown]                [k] 0xffffffff8046c5cc
  2.96%  ls       libuClibc-0.9.34-git.so  [.] memcpy
  2.25%  ls       libuClibc-0.9.34-git.so  [.] memset
  1.66%  ls       [unknown]                [k] 0xffffffff80666536
  1.54%  ls       libuClibc-0.9.34-git.so  [.] 0x000224d6
  1.18%  ls       libuClibc-0.9.34-git.so  [.] 0x00022472
 -----------&gt;8----------

With that change perf output looks much better now:
 -----------&gt;8----------
  8.21%  ls       [kernel.kallsyms]        [k] memset
  3.52%  ls       libuClibc-0.9.34-git.so  [.] memcpy
  2.11%  ls       libuClibc-0.9.34-git.so  [.] malloc
  1.88%  ls       libuClibc-0.9.34-git.so  [.] memset
  1.64%  ls       [kernel.kallsyms]        [k] _raw_spin_unlock_irqrestore
  1.41%  ls       [kernel.kallsyms]        [k] __d_lookup_rcu
 -----------&gt;8----------

Signed-off-by: Alexey Brodkin &lt;abrodkin@synopsys.com&gt;
Cc: arc-linux-dev@synopsys.com
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Signed-off-by: Luis Henriques &lt;luis.henriques@canonical.com&gt;
</pre>
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</entry>
<entry>
<title>ARC: add smp barriers around atomics per Documentation/atomic_ops.txt</title>
<updated>2015-07-15T09:00:53+00:00</updated>
<author>
<name>Vineet Gupta</name>
<email>vgupta@synopsys.com</email>
</author>
<published>2014-11-20T10:12:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2ef1fe7a71c72264feae4d0e47a7c7c941642103'/>
<id>2ef1fe7a71c72264feae4d0e47a7c7c941642103</id>
<content type='text'>
commit 2576c28e3f623ed401db7e6197241865328620ef upstream.

 - arch_spin_lock/unlock were lacking the ACQUIRE/RELEASE barriers
   Since ARCv2 only provides load/load, store/store and all/all, we need
   the full barrier

 - LLOCK/SCOND based atomics, bitops, cmpxchg, which return modified
   values were lacking the explicit smp barriers.

 - Non LLOCK/SCOND varaints don't need the explicit barriers since that
   is implicity provided by the spin locks used to implement the
   critical section (the spin lock barriers in turn are also fixed in
   this commit as explained above

Cc: Paul E. McKenney &lt;paulmck@linux.vnet.ibm.com&gt;
Acked-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Signed-off-by: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Signed-off-by: Luis Henriques &lt;luis.henriques@canonical.com&gt;
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<pre>
commit 2576c28e3f623ed401db7e6197241865328620ef upstream.

 - arch_spin_lock/unlock were lacking the ACQUIRE/RELEASE barriers
   Since ARCv2 only provides load/load, store/store and all/all, we need
   the full barrier

 - LLOCK/SCOND based atomics, bitops, cmpxchg, which return modified
   values were lacking the explicit smp barriers.

 - Non LLOCK/SCOND varaints don't need the explicit barriers since that
   is implicity provided by the spin locks used to implement the
   critical section (the spin lock barriers in turn are also fixed in
   this commit as explained above

Cc: Paul E. McKenney &lt;paulmck@linux.vnet.ibm.com&gt;
Acked-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Signed-off-by: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Signed-off-by: Luis Henriques &lt;luis.henriques@canonical.com&gt;
</pre>
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</content>
</entry>
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