<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/arch/x86, branch v3.12.18</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>crypto: ghash-clmulni-intel - use C implementation for setkey()</title>
<updated>2014-04-18T09:07:21+00:00</updated>
<author>
<name>Ard Biesheuvel</name>
<email>ard.biesheuvel@linaro.org</email>
</author>
<published>2014-03-27T17:14:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=a9149a366f5be56e50e9ec52bad0f616293fb640'/>
<id>a9149a366f5be56e50e9ec52bad0f616293fb640</id>
<content type='text'>
commit 8ceee72808d1ae3fb191284afc2257a2be964725 upstream.

The GHASH setkey() function uses SSE registers but fails to call
kernel_fpu_begin()/kernel_fpu_end(). Instead of adding these calls, and
then having to deal with the restriction that they cannot be called from
interrupt context, move the setkey() implementation to the C domain.

Note that setkey() does not use any particular SSE features and is not
expected to become a performance bottleneck.

Signed-off-by: Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;
Acked-by: H. Peter Anvin &lt;hpa@linux.intel.com&gt;
Fixes: 0e1227d356e9b (crypto: ghash - Add PCLMULQDQ accelerated implementation)
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 8ceee72808d1ae3fb191284afc2257a2be964725 upstream.

The GHASH setkey() function uses SSE registers but fails to call
kernel_fpu_begin()/kernel_fpu_end(). Instead of adding these calls, and
then having to deal with the restriction that they cannot be called from
interrupt context, move the setkey() implementation to the C domain.

Note that setkey() does not use any particular SSE features and is not
expected to become a performance bottleneck.

Signed-off-by: Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;
Acked-by: H. Peter Anvin &lt;hpa@linux.intel.com&gt;
Fixes: 0e1227d356e9b (crypto: ghash - Add PCLMULQDQ accelerated implementation)
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>x86: fix boot on uniprocessor systems</title>
<updated>2014-04-03T08:32:28+00:00</updated>
<author>
<name>Artem Fetishev</name>
<email>artem_fetishev@epam.com</email>
</author>
<published>2014-03-28T20:33:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2c611dc0ca77c8012fee6f33cf05040b16dbee38'/>
<id>2c611dc0ca77c8012fee6f33cf05040b16dbee38</id>
<content type='text'>
commit 825600c0f20e595daaa7a6dd8970f84fa2a2ee57 upstream.

On x86 uniprocessor systems topology_physical_package_id() returns -1
which causes rapl_cpu_prepare() to leave rapl_pmu variable uninitialized
which leads to GPF in rapl_pmu_init().

See arch/x86/kernel/cpu/perf_event_intel_rapl.c.

It turns out that physical_package_id and core_id can actually be
retreived for uniprocessor systems too.  Enabling them also fixes
rapl_pmu code.

Signed-off-by: Artem Fetishev &lt;artem_fetishev@epam.com&gt;
Cc: Stephane Eranian &lt;eranian@google.com&gt;
Cc: Ingo Molnar &lt;mingo@elte.hu&gt;
Cc: "H. Peter Anvin" &lt;hpa@zytor.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Peter Zijlstra &lt;a.p.zijlstra@chello.nl&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: Jiri Slaby &lt;jslaby@suse.cz&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 825600c0f20e595daaa7a6dd8970f84fa2a2ee57 upstream.

On x86 uniprocessor systems topology_physical_package_id() returns -1
which causes rapl_cpu_prepare() to leave rapl_pmu variable uninitialized
which leads to GPF in rapl_pmu_init().

See arch/x86/kernel/cpu/perf_event_intel_rapl.c.

It turns out that physical_package_id and core_id can actually be
retreived for uniprocessor systems too.  Enabling them also fixes
rapl_pmu code.

Signed-off-by: Artem Fetishev &lt;artem_fetishev@epam.com&gt;
Cc: Stephane Eranian &lt;eranian@google.com&gt;
Cc: Ingo Molnar &lt;mingo@elte.hu&gt;
Cc: "H. Peter Anvin" &lt;hpa@zytor.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Peter Zijlstra &lt;a.p.zijlstra@chello.nl&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: Jiri Slaby &lt;jslaby@suse.cz&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Revert "xen: properly account for _PAGE_NUMA during xen pte translations"</title>
<updated>2014-04-03T08:32:26+00:00</updated>
<author>
<name>David Vrabel</name>
<email>david.vrabel@citrix.com</email>
</author>
<published>2014-03-25T10:38:37+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=1f21fba458a6e8352324cc86f2d6dc5ca16711f9'/>
<id>1f21fba458a6e8352324cc86f2d6dc5ca16711f9</id>
<content type='text'>
commit 5926f87fdaad4be3ed10cec563bf357915e55a86 upstream.

This reverts commit a9c8e4beeeb64c22b84c803747487857fe424b68.

PTEs in Xen PV guests must contain machine addresses if _PAGE_PRESENT
is set and pseudo-physical addresses is _PAGE_PRESENT is clear.

This is because during a domain save/restore (migration) the page
table entries are "canonicalised" and uncanonicalised". i.e., MFNs are
converted to PFNs during domain save so that on a restore the page
table entries may be rewritten with the new MFNs on the destination.
This canonicalisation is only done for PTEs that are present.

This change resulted in writing PTEs with MFNs if _PAGE_PROTNONE (or
_PAGE_NUMA) was set but _PAGE_PRESENT was clear.  These PTEs would be
migrated as-is which would result in unexpected behaviour in the
destination domain.  Either a) the MFN would be translated to the
wrong PFN/page; b) setting the _PAGE_PRESENT bit would clear the PTE
because the MFN is no longer owned by the domain; or c) the present
bit would not get set.

Symptoms include "Bad page" reports when munmapping after migrating a
domain.

Signed-off-by: David Vrabel &lt;david.vrabel@citrix.com&gt;
Acked-by: Konrad Rzeszutek Wilk &lt;konrad.wilk@oracle.com&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 5926f87fdaad4be3ed10cec563bf357915e55a86 upstream.

This reverts commit a9c8e4beeeb64c22b84c803747487857fe424b68.

PTEs in Xen PV guests must contain machine addresses if _PAGE_PRESENT
is set and pseudo-physical addresses is _PAGE_PRESENT is clear.

This is because during a domain save/restore (migration) the page
table entries are "canonicalised" and uncanonicalised". i.e., MFNs are
converted to PFNs during domain save so that on a restore the page
table entries may be rewritten with the new MFNs on the destination.
This canonicalisation is only done for PTEs that are present.

This change resulted in writing PTEs with MFNs if _PAGE_PROTNONE (or
_PAGE_NUMA) was set but _PAGE_PRESENT was clear.  These PTEs would be
migrated as-is which would result in unexpected behaviour in the
destination domain.  Either a) the MFN would be translated to the
wrong PFN/page; b) setting the _PAGE_PRESENT bit would clear the PTE
because the MFN is no longer owned by the domain; or c) the present
bit would not get set.

Symptoms include "Bad page" reports when munmapping after migrating a
domain.

Signed-off-by: David Vrabel &lt;david.vrabel@citrix.com&gt;
Acked-by: Konrad Rzeszutek Wilk &lt;konrad.wilk@oracle.com&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arch/x86/mm/srat: Skip NUMA_NO_NODE while parsing SLIT</title>
<updated>2014-04-03T08:32:11+00:00</updated>
<author>
<name>Toshi Kani</name>
<email>toshi.kani@hp.com</email>
</author>
<published>2014-01-21T22:33:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=ee023577f66a1c647011384cb839d09747a083a4'/>
<id>ee023577f66a1c647011384cb839d09747a083a4</id>
<content type='text'>
commit a85eba8814631d0d48361c8b9a7ee0984e80c03c upstream.

When ACPI SLIT table has an I/O locality (i.e. a locality
unique to an I/O device), numa_set_distance() emits this warning
message:

 NUMA: Warning: node ids are out of bound, from=-1 to=-1 distance=10

acpi_numa_slit_init() calls numa_set_distance() with
pxm_to_node(), which assumes that all localities have been
parsed with SRAT previously.  SRAT does not list I/O localities,
where as SLIT lists all localities including I/Os.  Hence,
pxm_to_node() returns NUMA_NO_NODE (-1) for an I/O locality.

I/O localities are not supported and are ignored today, but emitting
such warning message leads to unnecessary confusion.

Change acpi_numa_slit_init() to avoid calling
numa_set_distance() with NUMA_NO_NODE.

Signed-off-by: Toshi Kani &lt;toshi.kani@hp.com&gt;
Acked-by: David Rientjes &lt;rientjes@google.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Yinghai Lu &lt;yinghai@kernel.org&gt;
Link: http://lkml.kernel.org/n/tip-dSvpjjvp8aMzs1ybkftxohlh@git.kernel.org
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit a85eba8814631d0d48361c8b9a7ee0984e80c03c upstream.

When ACPI SLIT table has an I/O locality (i.e. a locality
unique to an I/O device), numa_set_distance() emits this warning
message:

 NUMA: Warning: node ids are out of bound, from=-1 to=-1 distance=10

acpi_numa_slit_init() calls numa_set_distance() with
pxm_to_node(), which assumes that all localities have been
parsed with SRAT previously.  SRAT does not list I/O localities,
where as SLIT lists all localities including I/Os.  Hence,
pxm_to_node() returns NUMA_NO_NODE (-1) for an I/O locality.

I/O localities are not supported and are ignored today, but emitting
such warning message leads to unnecessary confusion.

Change acpi_numa_slit_init() to avoid calling
numa_set_distance() with NUMA_NO_NODE.

Signed-off-by: Toshi Kani &lt;toshi.kani@hp.com&gt;
Acked-by: David Rientjes &lt;rientjes@google.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Yinghai Lu &lt;yinghai@kernel.org&gt;
Link: http://lkml.kernel.org/n/tip-dSvpjjvp8aMzs1ybkftxohlh@git.kernel.org
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>crypto: sha256_ssse3 - also test for BMI2</title>
<updated>2014-04-03T08:32:11+00:00</updated>
<author>
<name>Oliver Neukum</name>
<email>oneukum@suse.de</email>
</author>
<published>2013-10-01T12:34:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=6b11f0eda2cfd467f186b303bf8d9e4de08cf70b'/>
<id>6b11f0eda2cfd467f186b303bf8d9e4de08cf70b</id>
<content type='text'>
commit 16c0c4e1656c14ef9deac189a4240b5ca19c6919 upstream.

The AVX2 implementation also uses BMI2 instructions,
but doesn't test for their availability. The assumption
that AVX2 and BMI2 always go together is false. Some
Haswells have AVX2 but not BMI2.

Signed-off-by: Oliver Neukum &lt;oneukum@suse.de&gt;
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 16c0c4e1656c14ef9deac189a4240b5ca19c6919 upstream.

The AVX2 implementation also uses BMI2 instructions,
but doesn't test for their availability. The assumption
that AVX2 and BMI2 always go together is false. Some
Haswells have AVX2 but not BMI2.

Signed-off-by: Oliver Neukum &lt;oneukum@suse.de&gt;
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>KVM: VMX: fix use after free of vmx-&gt;loaded_vmcs</title>
<updated>2014-03-31T12:22:33+00:00</updated>
<author>
<name>Marcelo Tosatti</name>
<email>mtosatti@redhat.com</email>
</author>
<published>2014-01-03T19:00:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=5b6325c676690b26685c55998c49cea0a437fd24'/>
<id>5b6325c676690b26685c55998c49cea0a437fd24</id>
<content type='text'>
commit 26a865f4aa8e66a6d94958de7656f7f1b03c6c56 upstream.

After free_loaded_vmcs executes, the "loaded_vmcs" structure
is kfreed, and now vmx-&gt;loaded_vmcs points to a kfreed area.
Subsequent free_loaded_vmcs then attempts to manipulate
vmx-&gt;loaded_vmcs.

Switch the order to avoid the problem.

https://bugzilla.redhat.com/show_bug.cgi?id=1047892

Reviewed-by: Jan Kiszka &lt;jan.kiszka@siemens.com&gt;
Signed-off-by: Marcelo Tosatti &lt;mtosatti@redhat.com&gt;
Cc: Josh Boyer &lt;jwboyer@fedoraproject.org&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 26a865f4aa8e66a6d94958de7656f7f1b03c6c56 upstream.

After free_loaded_vmcs executes, the "loaded_vmcs" structure
is kfreed, and now vmx-&gt;loaded_vmcs points to a kfreed area.
Subsequent free_loaded_vmcs then attempts to manipulate
vmx-&gt;loaded_vmcs.

Switch the order to avoid the problem.

https://bugzilla.redhat.com/show_bug.cgi?id=1047892

Reviewed-by: Jan Kiszka &lt;jan.kiszka@siemens.com&gt;
Signed-off-by: Marcelo Tosatti &lt;mtosatti@redhat.com&gt;
Cc: Josh Boyer &lt;jwboyer@fedoraproject.org&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>KVM: x86: handle invalid root_hpa everywhere</title>
<updated>2014-03-31T12:22:33+00:00</updated>
<author>
<name>Marcelo Tosatti</name>
<email>mtosatti@redhat.com</email>
</author>
<published>2014-01-03T19:09:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=df071bf16dc2e1d12d36f8d3861df672376d5c75'/>
<id>df071bf16dc2e1d12d36f8d3861df672376d5c75</id>
<content type='text'>
commit 37f6a4e237303549c8676dfe1fd1991ceab512eb upstream.

Rom Freiman &lt;rom@stratoscale.com&gt; notes other code paths vulnerable to
bug fixed by 989c6b34f6a9480e397b.

Signed-off-by: Marcelo Tosatti &lt;mtosatti@redhat.com&gt;
Cc: Josh Boyer &lt;jwboyer@fedoraproject.org&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 37f6a4e237303549c8676dfe1fd1991ceab512eb upstream.

Rom Freiman &lt;rom@stratoscale.com&gt; notes other code paths vulnerable to
bug fixed by 989c6b34f6a9480e397b.

Signed-off-by: Marcelo Tosatti &lt;mtosatti@redhat.com&gt;
Cc: Josh Boyer &lt;jwboyer@fedoraproject.org&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>KVM: MMU: handle invalid root_hpa at __direct_map</title>
<updated>2014-03-31T12:22:32+00:00</updated>
<author>
<name>Marcelo Tosatti</name>
<email>mtosatti@redhat.com</email>
</author>
<published>2013-12-19T17:28:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=0334c2e03c00144d2ff68c97a1ff93a640883c57'/>
<id>0334c2e03c00144d2ff68c97a1ff93a640883c57</id>
<content type='text'>
commit 989c6b34f6a9480e397b170cc62237e89bf4fdb9 upstream.

It is possible for __direct_map to be called on invalid root_hpa
(-1), two examples:

1) try_async_pf -&gt; can_do_async_pf
    -&gt; vmx_interrupt_allowed -&gt; nested_vmx_vmexit
2) vmx_handle_exit -&gt; vmx_interrupt_allowed -&gt; nested_vmx_vmexit

Then to load_vmcs12_host_state and kvm_mmu_reset_context.

Check for this possibility, let fault exception be regenerated.

BZ: https://bugzilla.redhat.com/show_bug.cgi?id=924916

Signed-off-by: Marcelo Tosatti &lt;mtosatti@redhat.com&gt;
Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Cc: Josh Boyer &lt;jwboyer@fedoraproject.org&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 989c6b34f6a9480e397b170cc62237e89bf4fdb9 upstream.

It is possible for __direct_map to be called on invalid root_hpa
(-1), two examples:

1) try_async_pf -&gt; can_do_async_pf
    -&gt; vmx_interrupt_allowed -&gt; nested_vmx_vmexit
2) vmx_handle_exit -&gt; vmx_interrupt_allowed -&gt; nested_vmx_vmexit

Then to load_vmcs12_host_state and kvm_mmu_reset_context.

Check for this possibility, let fault exception be regenerated.

BZ: https://bugzilla.redhat.com/show_bug.cgi?id=924916

Signed-off-by: Marcelo Tosatti &lt;mtosatti@redhat.com&gt;
Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Cc: Josh Boyer &lt;jwboyer@fedoraproject.org&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>x86: bpf_jit: support negative offsets</title>
<updated>2014-03-31T12:22:29+00:00</updated>
<author>
<name>Alexei Starovoitov</name>
<email>ast@plumgrid.com</email>
</author>
<published>2014-03-10T22:56:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=03961b13eea339809447597c9222a87a3ee0d059'/>
<id>03961b13eea339809447597c9222a87a3ee0d059</id>
<content type='text'>
commit fdfaf64e75397567257e1051931f9a3377360665 upstream.

Commit a998d4342337 claimed to introduce negative offset support to x86 jit,
but it couldn't be working, since at the time of the execution
of LD+ABS or LD+IND instructions via call into
bpf_internal_load_pointer_neg_helper() the %edx (3rd argument of this func)
had junk value instead of access size in bytes (1 or 2 or 4).

Store size into %edx instead of %ecx (what original commit intended to do)

Fixes: a998d4342337 ("bpf jit: Let the x86 jit handle negative offsets")
Signed-off-by: Alexei Starovoitov &lt;ast@plumgrid.com&gt;
Cc: Jan Seiffert &lt;kaffeemonster@googlemail.com&gt;
Cc: Eric Dumazet &lt;edumazet@google.com&gt;
Acked-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit fdfaf64e75397567257e1051931f9a3377360665 upstream.

Commit a998d4342337 claimed to introduce negative offset support to x86 jit,
but it couldn't be working, since at the time of the execution
of LD+ABS or LD+IND instructions via call into
bpf_internal_load_pointer_neg_helper() the %edx (3rd argument of this func)
had junk value instead of access size in bytes (1 or 2 or 4).

Store size into %edx instead of %ecx (what original commit intended to do)

Fixes: a998d4342337 ("bpf jit: Let the x86 jit handle negative offsets")
Signed-off-by: Alexei Starovoitov &lt;ast@plumgrid.com&gt;
Cc: Jan Seiffert &lt;kaffeemonster@googlemail.com&gt;
Cc: Eric Dumazet &lt;edumazet@google.com&gt;
Acked-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>x86, fpu: Check tsk_used_math() in kernel_fpu_end() for eager FPU</title>
<updated>2014-03-24T08:45:05+00:00</updated>
<author>
<name>Suresh Siddha</name>
<email>sbsiddha@gmail.com</email>
</author>
<published>2014-02-03T06:56:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=41531218f30582610b5b2bdd16246526792b0cbe'/>
<id>41531218f30582610b5b2bdd16246526792b0cbe</id>
<content type='text'>
commit 731bd6a93a6e9172094a2322bd0ee964bb1f4d63 upstream.

For non-eager fpu mode, thread's fpu state is allocated during the first
fpu usage (in the context of device not available exception). This
(math_state_restore()) can be a blocking call and hence we enable
interrupts (which were originally disabled when the exception happened),
allocate memory and disable interrupts etc.

But the eager-fpu mode, call's the same math_state_restore() from
kernel_fpu_end(). The assumption being that tsk_used_math() is always
set for the eager-fpu mode and thus avoid the code path of enabling
interrupts, allocating fpu state using blocking call and disable
interrupts etc.

But the below issue was noticed by Maarten Baert, Nate Eldredge and
few others:

If a user process dumps core on an ecrypt fs while aesni-intel is loaded,
we get a BUG() in __find_get_block() complaining that it was called with
interrupts disabled; then all further accesses to our ecrypt fs hang
and we have to reboot.

The aesni-intel code (encrypting the core file that we are writing) needs
the FPU and quite properly wraps its code in kernel_fpu_{begin,end}(),
the latter of which calls math_state_restore(). So after kernel_fpu_end(),
interrupts may be disabled, which nobody seems to expect, and they stay
that way until we eventually get to __find_get_block() which barfs.

For eager fpu, most the time, tsk_used_math() is true. At few instances
during thread exit, signal return handling etc, tsk_used_math() might
be false.

In kernel_fpu_end(), for eager-fpu, call math_state_restore()
only if tsk_used_math() is set. Otherwise, don't bother. Kernel code
path which cleared tsk_used_math() knows what needs to be done
with the fpu state.

Reported-by: Maarten Baert &lt;maarten-baert@hotmail.com&gt;
Reported-by: Nate Eldredge &lt;nate@thatsmathematics.com&gt;
Suggested-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Suresh Siddha &lt;sbsiddha@gmail.com&gt;
Link: http://lkml.kernel.org/r/1391410583.3801.6.camel@europa
Cc: George Spelvin &lt;linux@horizon.com&gt;
Signed-off-by: H. Peter Anvin &lt;hpa@linux.intel.com&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 731bd6a93a6e9172094a2322bd0ee964bb1f4d63 upstream.

For non-eager fpu mode, thread's fpu state is allocated during the first
fpu usage (in the context of device not available exception). This
(math_state_restore()) can be a blocking call and hence we enable
interrupts (which were originally disabled when the exception happened),
allocate memory and disable interrupts etc.

But the eager-fpu mode, call's the same math_state_restore() from
kernel_fpu_end(). The assumption being that tsk_used_math() is always
set for the eager-fpu mode and thus avoid the code path of enabling
interrupts, allocating fpu state using blocking call and disable
interrupts etc.

But the below issue was noticed by Maarten Baert, Nate Eldredge and
few others:

If a user process dumps core on an ecrypt fs while aesni-intel is loaded,
we get a BUG() in __find_get_block() complaining that it was called with
interrupts disabled; then all further accesses to our ecrypt fs hang
and we have to reboot.

The aesni-intel code (encrypting the core file that we are writing) needs
the FPU and quite properly wraps its code in kernel_fpu_{begin,end}(),
the latter of which calls math_state_restore(). So after kernel_fpu_end(),
interrupts may be disabled, which nobody seems to expect, and they stay
that way until we eventually get to __find_get_block() which barfs.

For eager fpu, most the time, tsk_used_math() is true. At few instances
during thread exit, signal return handling etc, tsk_used_math() might
be false.

In kernel_fpu_end(), for eager-fpu, call math_state_restore()
only if tsk_used_math() is set. Otherwise, don't bother. Kernel code
path which cleared tsk_used_math() knows what needs to be done
with the fpu state.

Reported-by: Maarten Baert &lt;maarten-baert@hotmail.com&gt;
Reported-by: Nate Eldredge &lt;nate@thatsmathematics.com&gt;
Suggested-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Suresh Siddha &lt;sbsiddha@gmail.com&gt;
Link: http://lkml.kernel.org/r/1391410583.3801.6.camel@europa
Cc: George Spelvin &lt;linux@horizon.com&gt;
Signed-off-by: H. Peter Anvin &lt;hpa@linux.intel.com&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</pre>
</div>
</content>
</entry>
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