<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/arch/arm, branch linux-3.19.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>ARM: dts: fix mmc node updates for exynos5250-spring</title>
<updated>2015-05-06T20:01:49+00:00</updated>
<author>
<name>Andreas Faerber</name>
<email>afaerber@suse.de</email>
</author>
<published>2015-03-17T16:25:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e4f3adf88ba5237adbff176ed08b1607f1a9fc24'/>
<id>e4f3adf88ba5237adbff176ed08b1607f1a9fc24</id>
<content type='text'>
commit 7e9e20b1faab02357501553d7f4e3efec1b4cfd3 upstream.

Resolve a merge conflict with mmc refactoring aaa25a5a33cb ("ARM: dts:
unuse the slot-node and deprecate the supports-highspeed for dw-mmc in
exynos") by dropping the slot@0 nodes, moving its bus-width property to
the mmc node and replacing supports-highspeed with cap-{mmc,sd}-highspeed,
matching exynos5250-snow.

Cc: Jaehoon Chung &lt;jh80.chung@samsung.com&gt;
Fixes: 53dd4138bb0a ("ARM: dts: Add exynos5250-spring device tree")
Signed-off-by: Andreas Faerber &lt;afaerber@suse.de&gt;
Reviewed-by: Javier Martinez Canillas &lt;javier.martinez@collabora.co.uk&gt;
Signed-off-by: Kukjin Kim &lt;kgene@kernel.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>
commit 7e9e20b1faab02357501553d7f4e3efec1b4cfd3 upstream.

Resolve a merge conflict with mmc refactoring aaa25a5a33cb ("ARM: dts:
unuse the slot-node and deprecate the supports-highspeed for dw-mmc in
exynos") by dropping the slot@0 nodes, moving its bus-width property to
the mmc node and replacing supports-highspeed with cap-{mmc,sd}-highspeed,
matching exynos5250-snow.

Cc: Jaehoon Chung &lt;jh80.chung@samsung.com&gt;
Fixes: 53dd4138bb0a ("ARM: dts: Add exynos5250-spring device tree")
Signed-off-by: Andreas Faerber &lt;afaerber@suse.de&gt;
Reviewed-by: Javier Martinez Canillas &lt;javier.martinez@collabora.co.uk&gt;
Signed-off-by: Kukjin Kim &lt;kgene@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ARM: dts: dove: Fix uart[23] reg property</title>
<updated>2015-05-06T20:01:49+00:00</updated>
<author>
<name>Sebastian Hesselbarth</name>
<email>sebastian.hesselbarth@gmail.com</email>
</author>
<published>2015-02-17T18:52:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=30dc82970a6a3b597d62624b88de719c491453ee'/>
<id>30dc82970a6a3b597d62624b88de719c491453ee</id>
<content type='text'>
commit a74cd13b807029397f7232449df929bac11fb228 upstream.

Fix Dove's register addresses of uart2 and uart3 nodes that seem to
be broken since ages due to a copy-and-paste error.

Signed-off-by: Sebastian Hesselbarth &lt;sebastian.hesselbarth@gmail.com&gt;
Acked-by: Gregory CLEMENT &lt;gregory.clement@free-electrons.com&gt;
Signed-off-by: Gregory CLEMENT &lt;gregory.clement@free-electrons.com&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>
commit a74cd13b807029397f7232449df929bac11fb228 upstream.

Fix Dove's register addresses of uart2 and uart3 nodes that seem to
be broken since ages due to a copy-and-paste error.

Signed-off-by: Sebastian Hesselbarth &lt;sebastian.hesselbarth@gmail.com&gt;
Acked-by: Gregory CLEMENT &lt;gregory.clement@free-electrons.com&gt;
Signed-off-by: Gregory CLEMENT &lt;gregory.clement@free-electrons.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ARM: at91/dt: sama5d3 xplained: add phy address for macb1</title>
<updated>2015-05-06T20:01:49+00:00</updated>
<author>
<name>Nicolas Ferre</name>
<email>nicolas.ferre@atmel.com</email>
</author>
<published>2015-03-31T08:56:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=4cd4bf4c9391fee778d115906ed6ab6d2081436b'/>
<id>4cd4bf4c9391fee778d115906ed6ab6d2081436b</id>
<content type='text'>
commit 98b80987c940956da48f0c703f60340128bb8521 upstream.

After 57a38effa598 (net: phy: micrel: disable broadcast for KSZ8081/KSZ8091)
the macb1 interface refuses to work properly because it tries
to cling to address 0 which isn't able to communicate in broadcast with
the mac anymore. The micrel phy on the board is actually configured
to show up at address 1.
Adding the phy node and its real address fixes the issue.

Signed-off-by: Nicolas Ferre &lt;nicolas.ferre@atmel.com&gt;
Cc: Johan Hovold &lt;johan@kernel.org&gt;
Signed-off-by: Olof Johansson &lt;olof@lixom.net&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>
commit 98b80987c940956da48f0c703f60340128bb8521 upstream.

After 57a38effa598 (net: phy: micrel: disable broadcast for KSZ8081/KSZ8091)
the macb1 interface refuses to work properly because it tries
to cling to address 0 which isn't able to communicate in broadcast with
the mac anymore. The micrel phy on the board is actually configured
to show up at address 1.
Adding the phy node and its real address fixes the issue.

Signed-off-by: Nicolas Ferre &lt;nicolas.ferre@atmel.com&gt;
Cc: Johan Hovold &lt;johan@kernel.org&gt;
Signed-off-by: Olof Johansson &lt;olof@lixom.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ARM: S3C64XX: Use fixed IRQ bases to avoid conflicts on Cragganmore</title>
<updated>2015-05-06T20:01:48+00:00</updated>
<author>
<name>Charles Keepax</name>
<email>ckeepax@opensource.wolfsonmicro.com</email>
</author>
<published>2015-03-26T16:58:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=22a08adb89148a47a82ad101b02443092a8c9f6b'/>
<id>22a08adb89148a47a82ad101b02443092a8c9f6b</id>
<content type='text'>
commit 4e330ae4ab2915444f1e6dca1358a910aa259362 upstream.

There are two PMICs on Cragganmore, currently one dynamically assign
its IRQ base and the other uses a fixed base. It is possible for the
statically assigned PMIC to fail if its IRQ is taken by the dynamically
assigned one. Fix this by statically assigning both the IRQ bases.

Signed-off-by: Charles Keepax &lt;ckeepax@opensource.wolfsonmicro.com&gt;
Signed-off-by: Kukjin Kim &lt;kgene@kernel.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>
commit 4e330ae4ab2915444f1e6dca1358a910aa259362 upstream.

There are two PMICs on Cragganmore, currently one dynamically assign
its IRQ base and the other uses a fixed base. It is possible for the
statically assigned PMIC to fail if its IRQ is taken by the dynamically
assigned one. Fix this by statically assigning both the IRQ bases.

Signed-off-by: Charles Keepax &lt;ckeepax@opensource.wolfsonmicro.com&gt;
Signed-off-by: Kukjin Kim &lt;kgene@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ARM: mvebu: Disable CPU Idle on Armada 38x</title>
<updated>2015-05-06T20:01:48+00:00</updated>
<author>
<name>Gregory CLEMENT</name>
<email>gregory.clement@free-electrons.com</email>
</author>
<published>2015-01-30T11:34:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ce45240c84179a7f965d08c69274ee992da585bf'/>
<id>ce45240c84179a7f965d08c69274ee992da585bf</id>
<content type='text'>
commit 548ae94c1cc7fc120848757249b9a542b1080ffb upstream.

On Armada 38x SoCs, under heavy I/O load, the system hangs when CPU
Idle is enabled. Waiting for a solution to this issue, this patch
disables the CPU Idle support for this SoC.

As CPU Hot plug support also uses some of the CPU Idle functions it is
also affected by the same issue. This patch disables it also for the
Armada 38x SoCs.

Signed-off-by: Gregory CLEMENT &lt;gregory.clement@free-electrons.com&gt;
Tested-by: Thomas Petazzoni &lt;thomas.petazzoni@free-electrons.com&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>
commit 548ae94c1cc7fc120848757249b9a542b1080ffb upstream.

On Armada 38x SoCs, under heavy I/O load, the system hangs when CPU
Idle is enabled. Waiting for a solution to this issue, this patch
disables the CPU Idle support for this SoC.

As CPU Hot plug support also uses some of the CPU Idle functions it is
also affected by the same issue. This patch disables it also for the
Armada 38x SoCs.

Signed-off-by: Gregory CLEMENT &lt;gregory.clement@free-electrons.com&gt;
Tested-by: Thomas Petazzoni &lt;thomas.petazzoni@free-electrons.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ARM: 8320/1: fix integer overflow in ELF_ET_DYN_BASE</title>
<updated>2015-05-06T20:01:48+00:00</updated>
<author>
<name>Andrey Ryabinin</name>
<email>a.ryabinin@samsung.com</email>
</author>
<published>2015-03-20T14:42:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=4dcafe787396525d0947ca5fc8ee7f186680ce3a'/>
<id>4dcafe787396525d0947ca5fc8ee7f186680ce3a</id>
<content type='text'>
commit 8defb3367fcd19d1af64c07792aade0747b54e0f upstream.

Usually ELF_ET_DYN_BASE is 2/3 of TASK_SIZE. With 3G/1G user/kernel
split this is not so, because 2*TASK_SIZE overflows 32 bits,
so the actual value of ELF_ET_DYN_BASE is:
	(2 * TASK_SIZE / 3) = 0x2a000000

When ASLR is disabled PIE binaries will load at ELF_ET_DYN_BASE address.
On 32bit platforms AddressSanitzer uses addresses [0x20000000 - 0x40000000]
for shadow memory [1]. So ASan doesn't work for PIE binaries when ASLR disabled
as it fails to map shadow memory.
Also after Kees's 'split ET_DYN ASLR from mmap ASLR' patchset PIE binaries
has a high chance of loading somewhere in between [0x2a000000 - 0x40000000]
even if ASLR enabled. This makes ASan with PIE absolutely incompatible.

Fix overflow by dividing TASK_SIZE prior to multiplying.
After this patch ELF_ET_DYN_BASE equals to (for CONFIG_VMSPLIT_3G=y):
	(TASK_SIZE / 3 * 2) = 0x7f555554

[1] https://code.google.com/p/address-sanitizer/wiki/AddressSanitizerAlgorithm#Mapping

Signed-off-by: Andrey Ryabinin &lt;a.ryabinin@samsung.com&gt;
Reported-by: Maria Guseva &lt;m.guseva@samsung.com&gt;
Signed-off-by: Russell King &lt;rmk+kernel@arm.linux.org.uk&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>
commit 8defb3367fcd19d1af64c07792aade0747b54e0f upstream.

Usually ELF_ET_DYN_BASE is 2/3 of TASK_SIZE. With 3G/1G user/kernel
split this is not so, because 2*TASK_SIZE overflows 32 bits,
so the actual value of ELF_ET_DYN_BASE is:
	(2 * TASK_SIZE / 3) = 0x2a000000

When ASLR is disabled PIE binaries will load at ELF_ET_DYN_BASE address.
On 32bit platforms AddressSanitzer uses addresses [0x20000000 - 0x40000000]
for shadow memory [1]. So ASan doesn't work for PIE binaries when ASLR disabled
as it fails to map shadow memory.
Also after Kees's 'split ET_DYN ASLR from mmap ASLR' patchset PIE binaries
has a high chance of loading somewhere in between [0x2a000000 - 0x40000000]
even if ASLR enabled. This makes ASan with PIE absolutely incompatible.

Fix overflow by dividing TASK_SIZE prior to multiplying.
After this patch ELF_ET_DYN_BASE equals to (for CONFIG_VMSPLIT_3G=y):
	(TASK_SIZE / 3 * 2) = 0x7f555554

[1] https://code.google.com/p/address-sanitizer/wiki/AddressSanitizerAlgorithm#Mapping

Signed-off-by: Andrey Ryabinin &lt;a.ryabinin@samsung.com&gt;
Reported-by: Maria Guseva &lt;m.guseva@samsung.com&gt;
Signed-off-by: Russell King &lt;rmk+kernel@arm.linux.org.uk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ARM: fix broken hibernation</title>
<updated>2015-05-06T20:01:48+00:00</updated>
<author>
<name>Russell King</name>
<email>rmk+kernel@arm.linux.org.uk</email>
</author>
<published>2015-04-01T15:20:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=87150f3f719deeea7bb26a8f38a75ecaf13d5de4'/>
<id>87150f3f719deeea7bb26a8f38a75ecaf13d5de4</id>
<content type='text'>
commit 767bf7e7a1e82a81c59778348d156993d0a6175d upstream.

Normally, when a CPU wants to clear a cache line to zero in the external
L2 cache, it would generate bus cycles to write each word as it would do
with any other data access.

However, a Cortex A9 connected to a L2C-310 has a specific feature where
the CPU can detect this operation, and signal that it wants to zero an
entire cache line.  This feature, known as Full Line of Zeros (FLZ),
involves a non-standard AXI signalling mechanism which only the L2C-310
can properly interpret.

There are separate enable bits in both the L2C-310 and the Cortex A9 -
the L2C-310 needs to be enabled and have the FLZ enable bit set in the
auxiliary control register before the Cortex A9 has this feature
enabled.

Unfortunately, the suspend code was not respecting this - it's not
obvious from the code:

swsusp_arch_suspend()
 cpu_suspend() /* saves the Cortex A9 auxiliary control register */
  arch_save_image()
  soft_restart() /* turns off FLZ in Cortex A9, and disables L2C */
   cpu_resume() /* restores the Cortex A9 registers, inc auxcr */

At this point, we end up with the L2C disabled, but the Cortex A9 with
FLZ enabled - which means any memset() or zeroing of a full cache line
will fail to take effect.

A similar issue exists in the resume path, but it's slightly more
complex:

swsusp_arch_suspend()
 cpu_suspend() /* saves the Cortex A9 auxiliary control register */
  arch_save_image() /* image with A9 auxcr saved */
...
swsusp_arch_resume()
 call_with_stack()
  arch_restore_image() /* restores image with A9 auxcr saved above */
  soft_restart() /* turns off FLZ in Cortex A9, and disables L2C */
   cpu_resume() /* restores the Cortex A9 registers, inc auxcr */

Again, here we end up with the L2C disabled, but Cortex A9 FLZ enabled.

There's no need to turn off the L2C in either of these two paths; there
are benefits from not doing so - for example, the page copies will be
faster with the L2C enabled.

Hence, fix this by providing a variant of soft_restart() which can be
used without turning the L2 cache controller off, and use it in both
of these paths to keep the L2C enabled across the respective resume
transitions.

Fixes: 8ef418c7178f ("ARM: l2c: trial at enabling some Cortex-A9 optimisations")
Reported-by: Sean Cross &lt;xobs@kosagi.com&gt;
Tested-by: Sean Cross &lt;xobs@kosagi.com&gt;
Signed-off-by: Russell King &lt;rmk+kernel@arm.linux.org.uk&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>
commit 767bf7e7a1e82a81c59778348d156993d0a6175d upstream.

Normally, when a CPU wants to clear a cache line to zero in the external
L2 cache, it would generate bus cycles to write each word as it would do
with any other data access.

However, a Cortex A9 connected to a L2C-310 has a specific feature where
the CPU can detect this operation, and signal that it wants to zero an
entire cache line.  This feature, known as Full Line of Zeros (FLZ),
involves a non-standard AXI signalling mechanism which only the L2C-310
can properly interpret.

There are separate enable bits in both the L2C-310 and the Cortex A9 -
the L2C-310 needs to be enabled and have the FLZ enable bit set in the
auxiliary control register before the Cortex A9 has this feature
enabled.

Unfortunately, the suspend code was not respecting this - it's not
obvious from the code:

swsusp_arch_suspend()
 cpu_suspend() /* saves the Cortex A9 auxiliary control register */
  arch_save_image()
  soft_restart() /* turns off FLZ in Cortex A9, and disables L2C */
   cpu_resume() /* restores the Cortex A9 registers, inc auxcr */

At this point, we end up with the L2C disabled, but the Cortex A9 with
FLZ enabled - which means any memset() or zeroing of a full cache line
will fail to take effect.

A similar issue exists in the resume path, but it's slightly more
complex:

swsusp_arch_suspend()
 cpu_suspend() /* saves the Cortex A9 auxiliary control register */
  arch_save_image() /* image with A9 auxcr saved */
...
swsusp_arch_resume()
 call_with_stack()
  arch_restore_image() /* restores image with A9 auxcr saved above */
  soft_restart() /* turns off FLZ in Cortex A9, and disables L2C */
   cpu_resume() /* restores the Cortex A9 registers, inc auxcr */

Again, here we end up with the L2C disabled, but Cortex A9 FLZ enabled.

There's no need to turn off the L2C in either of these two paths; there
are benefits from not doing so - for example, the page copies will be
faster with the L2C enabled.

Hence, fix this by providing a variant of soft_restart() which can be
used without turning the L2 cache controller off, and use it in both
of these paths to keep the L2C enabled across the respective resume
transitions.

Fixes: 8ef418c7178f ("ARM: l2c: trial at enabling some Cortex-A9 optimisations")
Reported-by: Sean Cross &lt;xobs@kosagi.com&gt;
Tested-by: Sean Cross &lt;xobs@kosagi.com&gt;
Signed-off-by: Russell King &lt;rmk+kernel@arm.linux.org.uk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: KVM: Do not use pgd_index to index stage-2 pgd</title>
<updated>2015-05-06T20:01:44+00:00</updated>
<author>
<name>Marc Zyngier</name>
<email>marc.zyngier@arm.com</email>
</author>
<published>2015-03-10T19:07:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ce7a2289d658eddffa9781c9577df03bede2c3fb'/>
<id>ce7a2289d658eddffa9781c9577df03bede2c3fb</id>
<content type='text'>
commit 04b8dc85bf4a64517e3cf20e409eeaa503b15cc1 upstream.

The kernel's pgd_index macro is designed to index a normal, page
sized array. KVM is a bit diffferent, as we can use concatenated
pages to have a bigger address space (for example 40bit IPA with
4kB pages gives us an 8kB PGD.

In the above case, the use of pgd_index will always return an index
inside the first 4kB, which makes a guest that has memory above
0x8000000000 rather unhappy, as it spins forever in a page fault,
whist the host happilly corrupts the lower pgd.

The obvious fix is to get our own kvm_pgd_index that does the right
thing(tm).

Tested on X-Gene with a hacked kvmtool that put memory at a stupidly
high address.

Reviewed-by: Christoffer Dall &lt;christoffer.dall@linaro.org&gt;
Signed-off-by: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Signed-off-by: Christoffer Dall &lt;christoffer.dall@linaro.org&gt;
Signed-off-by: Shannon Zhao &lt;shannon.zhao@linaro.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>
commit 04b8dc85bf4a64517e3cf20e409eeaa503b15cc1 upstream.

The kernel's pgd_index macro is designed to index a normal, page
sized array. KVM is a bit diffferent, as we can use concatenated
pages to have a bigger address space (for example 40bit IPA with
4kB pages gives us an 8kB PGD.

In the above case, the use of pgd_index will always return an index
inside the first 4kB, which makes a guest that has memory above
0x8000000000 rather unhappy, as it spins forever in a page fault,
whist the host happilly corrupts the lower pgd.

The obvious fix is to get our own kvm_pgd_index that does the right
thing(tm).

Tested on X-Gene with a hacked kvmtool that put memory at a stupidly
high address.

Reviewed-by: Christoffer Dall &lt;christoffer.dall@linaro.org&gt;
Signed-off-by: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Signed-off-by: Christoffer Dall &lt;christoffer.dall@linaro.org&gt;
Signed-off-by: Shannon Zhao &lt;shannon.zhao@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: KVM: Fix stage-2 PGD allocation to have per-page refcounting</title>
<updated>2015-05-06T20:01:44+00:00</updated>
<author>
<name>Marc Zyngier</name>
<email>marc.zyngier@arm.com</email>
</author>
<published>2015-03-10T19:06:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1cb2f1488f628b6103f98e14b3b2461a790520b6'/>
<id>1cb2f1488f628b6103f98e14b3b2461a790520b6</id>
<content type='text'>
commit a987370f8e7a1677ae385042644326d9cd145a20 upstream.

We're using __get_free_pages with to allocate the guest's stage-2
PGD. The standard behaviour of this function is to return a set of
pages where only the head page has a valid refcount.

This behaviour gets us into trouble when we're trying to increment
the refcount on a non-head page:

page:ffff7c00cfb693c0 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x4000000000000000()
page dumped because: VM_BUG_ON_PAGE((*({ __attribute__((unused)) typeof((&amp;page-&gt;_count)-&gt;counter) __var = ( typeof((&amp;page-&gt;_count)-&gt;counter)) 0; (volatile typeof((&amp;page-&gt;_count)-&gt;counter) *)&amp;((&amp;page-&gt;_count)-&gt;counter); })) &lt;= 0)
BUG: failure at include/linux/mm.h:548/get_page()!
Kernel panic - not syncing: BUG!
CPU: 1 PID: 1695 Comm: kvm-vcpu-0 Not tainted 4.0.0-rc1+ #3825
Hardware name: APM X-Gene Mustang board (DT)
Call trace:
[&lt;ffff80000008a09c&gt;] dump_backtrace+0x0/0x13c
[&lt;ffff80000008a1e8&gt;] show_stack+0x10/0x1c
[&lt;ffff800000691da8&gt;] dump_stack+0x74/0x94
[&lt;ffff800000690d78&gt;] panic+0x100/0x240
[&lt;ffff8000000a0bc4&gt;] stage2_get_pmd+0x17c/0x2bc
[&lt;ffff8000000a1dc4&gt;] kvm_handle_guest_abort+0x4b4/0x6b0
[&lt;ffff8000000a420c&gt;] handle_exit+0x58/0x180
[&lt;ffff80000009e7a4&gt;] kvm_arch_vcpu_ioctl_run+0x114/0x45c
[&lt;ffff800000099df4&gt;] kvm_vcpu_ioctl+0x2e0/0x754
[&lt;ffff8000001c0a18&gt;] do_vfs_ioctl+0x424/0x5c8
[&lt;ffff8000001c0bfc&gt;] SyS_ioctl+0x40/0x78
CPU0: stopping

A possible approach for this is to split the compound page using
split_page() at allocation time, and change the teardown path to
free one page at a time.  It turns out that alloc_pages_exact() and
free_pages_exact() does exactly that.

While we're at it, the PGD allocation code is reworked to reduce
duplication.

This has been tested on an X-Gene platform with a 4kB/48bit-VA host
kernel, and kvmtool hacked to place memory in the second page of
the hardware PGD (PUD for the host kernel). Also regression-tested
on a Cubietruck (Cortex-A7).

 [ Reworked to use alloc_pages_exact() and free_pages_exact() and to
   return pointers directly instead of by reference as arguments
    - Christoffer ]

Reported-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Signed-off-by: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Signed-off-by: Christoffer Dall &lt;christoffer.dall@linaro.org&gt;
Signed-off-by: Shannon Zhao &lt;shannon.zhao@linaro.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>
commit a987370f8e7a1677ae385042644326d9cd145a20 upstream.

We're using __get_free_pages with to allocate the guest's stage-2
PGD. The standard behaviour of this function is to return a set of
pages where only the head page has a valid refcount.

This behaviour gets us into trouble when we're trying to increment
the refcount on a non-head page:

page:ffff7c00cfb693c0 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x4000000000000000()
page dumped because: VM_BUG_ON_PAGE((*({ __attribute__((unused)) typeof((&amp;page-&gt;_count)-&gt;counter) __var = ( typeof((&amp;page-&gt;_count)-&gt;counter)) 0; (volatile typeof((&amp;page-&gt;_count)-&gt;counter) *)&amp;((&amp;page-&gt;_count)-&gt;counter); })) &lt;= 0)
BUG: failure at include/linux/mm.h:548/get_page()!
Kernel panic - not syncing: BUG!
CPU: 1 PID: 1695 Comm: kvm-vcpu-0 Not tainted 4.0.0-rc1+ #3825
Hardware name: APM X-Gene Mustang board (DT)
Call trace:
[&lt;ffff80000008a09c&gt;] dump_backtrace+0x0/0x13c
[&lt;ffff80000008a1e8&gt;] show_stack+0x10/0x1c
[&lt;ffff800000691da8&gt;] dump_stack+0x74/0x94
[&lt;ffff800000690d78&gt;] panic+0x100/0x240
[&lt;ffff8000000a0bc4&gt;] stage2_get_pmd+0x17c/0x2bc
[&lt;ffff8000000a1dc4&gt;] kvm_handle_guest_abort+0x4b4/0x6b0
[&lt;ffff8000000a420c&gt;] handle_exit+0x58/0x180
[&lt;ffff80000009e7a4&gt;] kvm_arch_vcpu_ioctl_run+0x114/0x45c
[&lt;ffff800000099df4&gt;] kvm_vcpu_ioctl+0x2e0/0x754
[&lt;ffff8000001c0a18&gt;] do_vfs_ioctl+0x424/0x5c8
[&lt;ffff8000001c0bfc&gt;] SyS_ioctl+0x40/0x78
CPU0: stopping

A possible approach for this is to split the compound page using
split_page() at allocation time, and change the teardown path to
free one page at a time.  It turns out that alloc_pages_exact() and
free_pages_exact() does exactly that.

While we're at it, the PGD allocation code is reworked to reduce
duplication.

This has been tested on an X-Gene platform with a 4kB/48bit-VA host
kernel, and kvmtool hacked to place memory in the second page of
the hardware PGD (PUD for the host kernel). Also regression-tested
on a Cubietruck (Cortex-A7).

 [ Reworked to use alloc_pages_exact() and free_pages_exact() and to
   return pointers directly instead of by reference as arguments
    - Christoffer ]

Reported-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Signed-off-by: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Signed-off-by: Christoffer Dall &lt;christoffer.dall@linaro.org&gt;
Signed-off-by: Shannon Zhao &lt;shannon.zhao@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ARM: KVM: Fix size check in __coherent_cache_guest_page</title>
<updated>2015-05-06T20:01:44+00:00</updated>
<author>
<name>Jan Kiszka</name>
<email>jan.kiszka@siemens.com</email>
</author>
<published>2015-02-07T21:21:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d0fd61c7048d4741ee86fb1ac314df19b49747da'/>
<id>d0fd61c7048d4741ee86fb1ac314df19b49747da</id>
<content type='text'>
commit a050dfb21cc22ac0c666d52531040c1bc48184cc upstream.

The check is supposed to catch page-unaligned sizes, not the inverse.

Signed-off-by: Jan Kiszka &lt;jan.kiszka@siemens.com&gt;
Signed-off-by: Christoffer Dall &lt;christoffer.dall@linaro.org&gt;
Signed-off-by: Shannon Zhao &lt;shannon.zhao@linaro.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>
commit a050dfb21cc22ac0c666d52531040c1bc48184cc upstream.

The check is supposed to catch page-unaligned sizes, not the inverse.

Signed-off-by: Jan Kiszka &lt;jan.kiszka@siemens.com&gt;
Signed-off-by: Christoffer Dall &lt;christoffer.dall@linaro.org&gt;
Signed-off-by: Shannon Zhao &lt;shannon.zhao@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
</feed>
