<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/arch, branch v4.12</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>Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus</title>
<updated>2017-07-02T18:53:44+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2017-07-02T18:53:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=79c496816963aa0561868b43c2c950dfeb282639'/>
<id>79c496816963aa0561868b43c2c950dfeb282639</id>
<content type='text'>
Pull MIPS fixes from Ralf Baechle:
 "Here's a final round of fixes for 4.12:

   - Fix misordered instructions in assembly code making kenel startup
     via UHB unreliable.

   - Fix special case of MADDF and MADDF emulation.

   - Fix alignment issue in address calculation in pm-cps on 64 bit.

   - Fix IRQ tracing &amp; lockdep when rescheduling

   - Systems with MAARs require post-DMA cache flushes.

  The reordering fix and the MADDF/MSUBF fix have sat in linux-next for
  a number of days. The others haven't propagated from my pull tree to
  linux-next yet but all have survived manual testing and Imagination's
  automated test system and there are no pending bug reports"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: Avoid accidental raw backtrace
  MIPS: Perform post-DMA cache flushes on systems with MAARs
  MIPS: Fix IRQ tracing &amp; lockdep when rescheduling
  MIPS: pm-cps: Drop manual cache-line alignment of ready_count
  MIPS: math-emu: Handle zero accumulator case in MADDF and MSUBF separately
  MIPS: head: Reorder instructions missing a delay slot
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull MIPS fixes from Ralf Baechle:
 "Here's a final round of fixes for 4.12:

   - Fix misordered instructions in assembly code making kenel startup
     via UHB unreliable.

   - Fix special case of MADDF and MADDF emulation.

   - Fix alignment issue in address calculation in pm-cps on 64 bit.

   - Fix IRQ tracing &amp; lockdep when rescheduling

   - Systems with MAARs require post-DMA cache flushes.

  The reordering fix and the MADDF/MSUBF fix have sat in linux-next for
  a number of days. The others haven't propagated from my pull tree to
  linux-next yet but all have survived manual testing and Imagination's
  automated test system and there are no pending bug reports"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: Avoid accidental raw backtrace
  MIPS: Perform post-DMA cache flushes on systems with MAARs
  MIPS: Fix IRQ tracing &amp; lockdep when rescheduling
  MIPS: pm-cps: Drop manual cache-line alignment of ready_count
  MIPS: math-emu: Handle zero accumulator case in MADDF and MSUBF separately
  MIPS: head: Reorder instructions missing a delay slot
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm</title>
<updated>2017-07-02T17:09:40+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2017-07-02T17:09:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=3a61a54cd72c93afa3b7246e3ed06f26ed37fde7'/>
<id>3a61a54cd72c93afa3b7246e3ed06f26ed37fde7</id>
<content type='text'>
Pull ARM fix from Russell King:
 "One final fix for 4.12 - Doug found a boot failure case triggered by
  requesting a non-even MB vmalloc size"

* 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm:
  ARM: 8685/1: ensure memblock-limit is pmd-aligned
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull ARM fix from Russell King:
 "One final fix for 4.12 - Doug found a boot failure case triggered by
  requesting a non-even MB vmalloc size"

* 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm:
  ARM: 8685/1: ensure memblock-limit is pmd-aligned
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2017-07-01T16:10:17+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2017-07-01T16:10:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=e18aca0236a2dac4a134ace4685e97ad09d3605b'/>
<id>e18aca0236a2dac4a134ace4685e97ad09d3605b</id>
<content type='text'>
Pull x86 fixes from Thomas Gleixner:
 "Fixlets for x86:

   - Prevent kexec crash when KASLR is enabled, which was caused by an
     address calculation bug

   - Restore the freeing of PUDs on memory hot remove

   - Correct a negated pointer check in the intel uncore performance
     monitoring driver

   - Plug a memory leak in an error exit path in the RDT code"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/intel_rdt: Fix memory leak on mount failure
  x86/boot/KASLR: Fix kexec crash due to 'virt_addr' calculation bug
  x86/boot/KASLR: Add checking for the offset of kernel virtual address randomization
  perf/x86/intel/uncore: Fix wrong box pointer check
  x86/mm/hotplug: Fix BUG_ON() after hot-remove by not freeing PUD
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull x86 fixes from Thomas Gleixner:
 "Fixlets for x86:

   - Prevent kexec crash when KASLR is enabled, which was caused by an
     address calculation bug

   - Restore the freeing of PUDs on memory hot remove

   - Correct a negated pointer check in the intel uncore performance
     monitoring driver

   - Plug a memory leak in an error exit path in the RDT code"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/intel_rdt: Fix memory leak on mount failure
  x86/boot/KASLR: Fix kexec crash due to 'virt_addr' calculation bug
  x86/boot/KASLR: Add checking for the offset of kernel virtual address randomization
  perf/x86/intel/uncore: Fix wrong box pointer check
  x86/mm/hotplug: Fix BUG_ON() after hot-remove by not freeing PUD
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/intel_rdt: Fix memory leak on mount failure</title>
<updated>2017-06-30T19:20:00+00:00</updated>
<author>
<name>Vikas Shivappa</name>
<email>vikas.shivappa@linux.intel.com</email>
</author>
<published>2017-06-26T18:55:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=79298acc4ba097e9ab78644e3e38902d73547c92'/>
<id>79298acc4ba097e9ab78644e3e38902d73547c92</id>
<content type='text'>
If mount fails, the kn_info directory is not freed causing memory leak.

Add the missing error handling path.

Fixes: 4e978d06dedb ("x86/intel_rdt: Add "info" files to resctrl file system")
Signed-off-by: Vikas Shivappa &lt;vikas.shivappa@linux.intel.com&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: vikas.shivappa@intel.com
Cc: andi.kleen@intel.com
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1498503368-20173-3-git-send-email-vikas.shivappa@linux.intel.com

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
If mount fails, the kn_info directory is not freed causing memory leak.

Add the missing error handling path.

Fixes: 4e978d06dedb ("x86/intel_rdt: Add "info" files to resctrl file system")
Signed-off-by: Vikas Shivappa &lt;vikas.shivappa@linux.intel.com&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: vikas.shivappa@intel.com
Cc: andi.kleen@intel.com
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1498503368-20173-3-git-send-email-vikas.shivappa@linux.intel.com

</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'powerpc-4.12-8' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux</title>
<updated>2017-06-30T17:55:34+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2017-06-30T17:55:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=b4df2e3537bef7d867338063da56b557c50f68f2'/>
<id>b4df2e3537bef7d867338063da56b557c50f68f2</id>
<content type='text'>
Pull powerpc fixes from Michael Ellerman:
 "Hopefully the last two powerpc fixes for 4.12.

  The CXL one is larger than I'd usually send at rc7, but it fixes new
  code this cycle, so better to have it working for the release. It was
  actually sent a few weeks back but got blocked in testing behind
  another fix that was causing issues.

  We are still tracking one crash in v4.12-rc7, but only one person has
  reproduced it and the commit identified by bisect doesn't touch any of
  the relevant code, so I think it's 50/50 whether that commit is
  actually the problem or it's some code layout / toolchain issue.

  Two fixes for code we merged this cycle:

   - cxl: Fixes for Coherent Accelerator Interface Architecture 2.0

   - Avoid miscompilation w/GCC 4.6.3 on 32-bit - don't inline
     copy_to/from_user()

  Thanks to Al Viro, Larry Finger, Christophe Lombard"

* tag 'powerpc-4.12-8' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/32: Avoid miscompilation w/GCC 4.6.3 - don't inline copy_to/from_user()
  cxl: Fixes for Coherent Accelerator Interface Architecture 2.0
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull powerpc fixes from Michael Ellerman:
 "Hopefully the last two powerpc fixes for 4.12.

  The CXL one is larger than I'd usually send at rc7, but it fixes new
  code this cycle, so better to have it working for the release. It was
  actually sent a few weeks back but got blocked in testing behind
  another fix that was causing issues.

  We are still tracking one crash in v4.12-rc7, but only one person has
  reproduced it and the commit identified by bisect doesn't touch any of
  the relevant code, so I think it's 50/50 whether that commit is
  actually the problem or it's some code layout / toolchain issue.

  Two fixes for code we merged this cycle:

   - cxl: Fixes for Coherent Accelerator Interface Architecture 2.0

   - Avoid miscompilation w/GCC 4.6.3 on 32-bit - don't inline
     copy_to/from_user()

  Thanks to Al Viro, Larry Finger, Christophe Lombard"

* tag 'powerpc-4.12-8' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/32: Avoid miscompilation w/GCC 4.6.3 - don't inline copy_to/from_user()
  cxl: Fixes for Coherent Accelerator Interface Architecture 2.0
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'iommu-fixes-v4.12-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu</title>
<updated>2017-06-30T17:37:48+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2017-06-30T17:37:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=27ab862a3afdd7a0285b69a7475f8af7bd2434c4'/>
<id>27ab862a3afdd7a0285b69a7475f8af7bd2434c4</id>
<content type='text'>
Pull IOMMU fixes from Joerg Roedel:
 "Two fixes:

   - A fix for AMD IOMMU interrupt remapping code when IRQs are
     forwarded directly to KVM guests

   - Fixed check in the recently merged code to allow tboot with
     Intel VT-d disabled"

* tag 'iommu-fixes-v4.12-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
  iommu/amd: Fix interrupt remapping when disable guest_mode
  iommu/vt-d: Correctly disable Intel IOMMU force on
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull IOMMU fixes from Joerg Roedel:
 "Two fixes:

   - A fix for AMD IOMMU interrupt remapping code when IRQs are
     forwarded directly to KVM guests

   - Fixed check in the recently merged code to allow tboot with
     Intel VT-d disabled"

* tag 'iommu-fixes-v4.12-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
  iommu/amd: Fix interrupt remapping when disable guest_mode
  iommu/vt-d: Correctly disable Intel IOMMU force on
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/boot/KASLR: Fix kexec crash due to 'virt_addr' calculation bug</title>
<updated>2017-06-30T06:53:14+00:00</updated>
<author>
<name>Baoquan He</name>
<email>bhe@redhat.com</email>
</author>
<published>2017-06-27T12:39:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=8eabf42ae5237e6b699aeac687b5b629e3537c8d'/>
<id>8eabf42ae5237e6b699aeac687b5b629e3537c8d</id>
<content type='text'>
Kernel text KASLR is separated into physical address and virtual
address randomization. And for virtual address randomization, we
only randomiza to get an offset between 16M and KERNEL_IMAGE_SIZE.
So the initial value of 'virt_addr' should be LOAD_PHYSICAL_ADDR,
but not the original kernel loading address 'output'.

The bug will cause kernel boot failure if kernel is loaded at a different
position than the address, 16M, which is decided at compiled time.
Kexec/kdump is such practical case.

To fix it, just assign LOAD_PHYSICAL_ADDR to virt_addr as initial
value.

Tested-by: Dave Young &lt;dyoung@redhat.com&gt;
Signed-off-by: Baoquan He &lt;bhe@redhat.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Fixes: 8391c73 ("x86/KASLR: Randomize virtual address separately")
Link: http://lkml.kernel.org/r/1498567146-11990-3-git-send-email-bhe@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>
Kernel text KASLR is separated into physical address and virtual
address randomization. And for virtual address randomization, we
only randomiza to get an offset between 16M and KERNEL_IMAGE_SIZE.
So the initial value of 'virt_addr' should be LOAD_PHYSICAL_ADDR,
but not the original kernel loading address 'output'.

The bug will cause kernel boot failure if kernel is loaded at a different
position than the address, 16M, which is decided at compiled time.
Kexec/kdump is such practical case.

To fix it, just assign LOAD_PHYSICAL_ADDR to virt_addr as initial
value.

Tested-by: Dave Young &lt;dyoung@redhat.com&gt;
Signed-off-by: Baoquan He &lt;bhe@redhat.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Fixes: 8391c73 ("x86/KASLR: Randomize virtual address separately")
Link: http://lkml.kernel.org/r/1498567146-11990-3-git-send-email-bhe@redhat.com
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/boot/KASLR: Add checking for the offset of kernel virtual address randomization</title>
<updated>2017-06-30T06:53:14+00:00</updated>
<author>
<name>Baoquan He</name>
<email>bhe@redhat.com</email>
</author>
<published>2017-06-27T12:39:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=b892cb873ced2af57dc5a018557d128c53ed6ae0'/>
<id>b892cb873ced2af57dc5a018557d128c53ed6ae0</id>
<content type='text'>
For kernel text KASLR, the virtual address is confined to area of 1G,
[0xffffffff80000000, 0xffffffffc0000000). For the implemenataion of
virtual address randomization, we only randomize to get an offset
between 16M and 1G, then add this offset to the starting address,
0xffffffff80000000. Here 16M is the offset which is decided at linking
stage. So the amount of the local variable 'virt_addr' which respresents
the offset plus the kernel output size can not exceed KERNEL_IMAGE_SIZE.

Add a debug check for the offset. If out of bounds, print error
message and hang there.

Suggested-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Signed-off-by: Baoquan He &lt;bhe@redhat.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Link: http://lkml.kernel.org/r/1498567146-11990-2-git-send-email-bhe@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>
For kernel text KASLR, the virtual address is confined to area of 1G,
[0xffffffff80000000, 0xffffffffc0000000). For the implemenataion of
virtual address randomization, we only randomize to get an offset
between 16M and 1G, then add this offset to the starting address,
0xffffffff80000000. Here 16M is the offset which is decided at linking
stage. So the amount of the local variable 'virt_addr' which respresents
the offset plus the kernel output size can not exceed KERNEL_IMAGE_SIZE.

Add a debug check for the offset. If out of bounds, print error
message and hang there.

Suggested-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Signed-off-by: Baoquan He &lt;bhe@redhat.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Link: http://lkml.kernel.org/r/1498567146-11990-2-git-send-email-bhe@redhat.com
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>MIPS: Avoid accidental raw backtrace</title>
<updated>2017-06-30T02:42:15+00:00</updated>
<author>
<name>James Hogan</name>
<email>james.hogan@imgtec.com</email>
</author>
<published>2017-06-29T14:05:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=854236363370995a609a10b03e35fd3dc5e9e4a1'/>
<id>854236363370995a609a10b03e35fd3dc5e9e4a1</id>
<content type='text'>
Since commit 81a76d7119f6 ("MIPS: Avoid using unwind_stack() with
usermode") show_backtrace() invokes the raw backtracer when
cp0_status &amp; ST0_KSU indicates user mode to fix issues on EVA kernels
where user and kernel address spaces overlap.

However this is used by show_stack() which creates its own pt_regs on
the stack and leaves cp0_status uninitialised in most of the code paths.
This results in the non deterministic use of the raw back tracer
depending on the previous stack content.

show_stack() deals exclusively with kernel mode stacks anyway, so
explicitly initialise regs.cp0_status to KSU_KERNEL (i.e. 0) to ensure
we get a useful backtrace.

Fixes: 81a76d7119f6 ("MIPS: Avoid using unwind_stack() with usermode")
Signed-off-by: James Hogan &lt;james.hogan@imgtec.com&gt;
Cc: linux-mips@linux-mips.org
Cc: &lt;stable@vger.kernel.org&gt; # 3.15+
Patchwork: https://patchwork.linux-mips.org/patch/16656/
Signed-off-by: Ralf Baechle &lt;ralf@linux-mips.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Since commit 81a76d7119f6 ("MIPS: Avoid using unwind_stack() with
usermode") show_backtrace() invokes the raw backtracer when
cp0_status &amp; ST0_KSU indicates user mode to fix issues on EVA kernels
where user and kernel address spaces overlap.

However this is used by show_stack() which creates its own pt_regs on
the stack and leaves cp0_status uninitialised in most of the code paths.
This results in the non deterministic use of the raw back tracer
depending on the previous stack content.

show_stack() deals exclusively with kernel mode stacks anyway, so
explicitly initialise regs.cp0_status to KSU_KERNEL (i.e. 0) to ensure
we get a useful backtrace.

Fixes: 81a76d7119f6 ("MIPS: Avoid using unwind_stack() with usermode")
Signed-off-by: James Hogan &lt;james.hogan@imgtec.com&gt;
Cc: linux-mips@linux-mips.org
Cc: &lt;stable@vger.kernel.org&gt; # 3.15+
Patchwork: https://patchwork.linux-mips.org/patch/16656/
Signed-off-by: Ralf Baechle &lt;ralf@linux-mips.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>MIPS: Perform post-DMA cache flushes on systems with MAARs</title>
<updated>2017-06-30T02:40:46+00:00</updated>
<author>
<name>Paul Burton</name>
<email>paul.burton@imgtec.com</email>
</author>
<published>2017-06-13T17:01:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=cad482c1b1844136fc6d9e33f10d3386344fb045'/>
<id>cad482c1b1844136fc6d9e33f10d3386344fb045</id>
<content type='text'>
Recent CPUs from Imagination Technologies such as the I6400 or P6600 are
able to speculatively fetch data from memory into caches. This means
that if used in a system with non-coherent DMA they require that caches
be invalidated after a device performs DMA, and before the CPU reads the
DMA'd data, in order to ensure that stale values weren't speculatively
prefetched.

Such CPUs also introduced Memory Accessibility Attribute Registers
(MAARs) in order to control the regions in which they are allowed to
speculate. Thus we can use the presence of MAARs as a good indication
that the CPU requires the above cache maintenance. Use the presence of
MAARs to determine the result of cpu_needs_post_dma_flush() in the
default case, in order to handle these recent CPUs correctly.

Note that the return type of cpu_needs_post_dma_flush() is changed to
bool, such that it's clearer what's happening when cpu_has_maar is cast
to bool for the return value. If this patch were backported to a
pre-v4.7 kernel then MIPS_CPU_MAAR was 1ull&lt;&lt;34, so when cast to an int
we would incorrectly return 0. It so happens that MIPS_CPU_MAAR is
currently 1ull&lt;&lt;30, so when truncated to an int gives a non-zero value
anyway, but even so the implicit conversion from long long int to bool
makes it clearer to understand what will happen than the implicit
conversion from long long int to int would. The bool return type also
fits this usage better semantically, so seems like an all-round win.

Thanks to Ed for spotting the issue for pre-v4.7 kernels &amp; suggesting
the return type change.

Signed-off-by: Paul Burton &lt;paul.burton@imgtec.com&gt;
Reviewed-by: Bryan O'Donoghue &lt;pure.logic@nexus-software.ie&gt;
Tested-by: Bryan O'Donoghue &lt;pure.logic@nexus-software.ie&gt;
Cc: Ed Blake &lt;ed.blake@imgtec.com&gt;
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16363/
Signed-off-by: Ralf Baechle &lt;ralf@linux-mips.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Recent CPUs from Imagination Technologies such as the I6400 or P6600 are
able to speculatively fetch data from memory into caches. This means
that if used in a system with non-coherent DMA they require that caches
be invalidated after a device performs DMA, and before the CPU reads the
DMA'd data, in order to ensure that stale values weren't speculatively
prefetched.

Such CPUs also introduced Memory Accessibility Attribute Registers
(MAARs) in order to control the regions in which they are allowed to
speculate. Thus we can use the presence of MAARs as a good indication
that the CPU requires the above cache maintenance. Use the presence of
MAARs to determine the result of cpu_needs_post_dma_flush() in the
default case, in order to handle these recent CPUs correctly.

Note that the return type of cpu_needs_post_dma_flush() is changed to
bool, such that it's clearer what's happening when cpu_has_maar is cast
to bool for the return value. If this patch were backported to a
pre-v4.7 kernel then MIPS_CPU_MAAR was 1ull&lt;&lt;34, so when cast to an int
we would incorrectly return 0. It so happens that MIPS_CPU_MAAR is
currently 1ull&lt;&lt;30, so when truncated to an int gives a non-zero value
anyway, but even so the implicit conversion from long long int to bool
makes it clearer to understand what will happen than the implicit
conversion from long long int to int would. The bool return type also
fits this usage better semantically, so seems like an all-round win.

Thanks to Ed for spotting the issue for pre-v4.7 kernels &amp; suggesting
the return type change.

Signed-off-by: Paul Burton &lt;paul.burton@imgtec.com&gt;
Reviewed-by: Bryan O'Donoghue &lt;pure.logic@nexus-software.ie&gt;
Tested-by: Bryan O'Donoghue &lt;pure.logic@nexus-software.ie&gt;
Cc: Ed Blake &lt;ed.blake@imgtec.com&gt;
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16363/
Signed-off-by: Ralf Baechle &lt;ralf@linux-mips.org&gt;
</pre>
</div>
</content>
</entry>
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