<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/arch/arm64/kernel/alternative.c, branch v5.2</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234</title>
<updated>2019-06-19T15:09:07+00:00</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2019-06-03T05:44:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=caab277b1de0a22b675c4c95fc7b285ec2eb5bf5'/>
<id>caab277b1de0a22b675c4c95fc7b285ec2eb5bf5</id>
<content type='text'>
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation this program is
  distributed in the hope that it will be useful but without any
  warranty without even the implied warranty of merchantability or
  fitness for a particular purpose see the gnu general public license
  for more details you should have received a copy of the gnu general
  public license along with this program if not see http www gnu org
  licenses

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 503 file(s).

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Alexios Zavras &lt;alexios.zavras@intel.com&gt;
Reviewed-by: Allison Randal &lt;allison@lohutok.net&gt;
Reviewed-by: Enrico Weigelt &lt;info@metux.net&gt;
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation this program is
  distributed in the hope that it will be useful but without any
  warranty without even the implied warranty of merchantability or
  fitness for a particular purpose see the gnu general public license
  for more details you should have received a copy of the gnu general
  public license along with this program if not see http www gnu org
  licenses

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 503 file(s).

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Alexios Zavras &lt;alexios.zavras@intel.com&gt;
Reviewed-by: Allison Randal &lt;allison@lohutok.net&gt;
Reviewed-by: Enrico Weigelt &lt;info@metux.net&gt;
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: alternative: Apply alternatives early in boot process</title>
<updated>2019-02-06T10:05:20+00:00</updated>
<author>
<name>Daniel Thompson</name>
<email>daniel.thompson@linaro.org</email>
</author>
<published>2019-01-31T14:58:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0ceb0d56905e3d141fae77e5936d00eee9233473'/>
<id>0ceb0d56905e3d141fae77e5936d00eee9233473</id>
<content type='text'>
Currently alternatives are applied very late in the boot process (and
a long time after we enable scheduling). Some alternative sequences,
such as those that alter the way CPU context is stored, must be applied
much earlier in the boot sequence.

Introduce apply_boot_alternatives() to allow some alternatives to be
applied immediately after we detect the CPU features of the boot CPU.

Signed-off-by: Daniel Thompson &lt;daniel.thompson@linaro.org&gt;
[julien.thierry@arm.com: rename to fit new cpufeature framework better,
			 apply BOOT_SCOPE feature early in boot]
Signed-off-by: Julien Thierry &lt;julien.thierry@arm.com&gt;
Reviewed-by: Suzuki K Poulose &lt;suzuki.poulose@arm.com&gt;
Reviewed-by: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Cc: Will Deacon &lt;will.deacon@arm.com&gt;
Cc: Christoffer Dall &lt;christoffer.dall@arm.com&gt;
Cc: Suzuki K Poulose &lt;suzuki.poulose@arm.com&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Currently alternatives are applied very late in the boot process (and
a long time after we enable scheduling). Some alternative sequences,
such as those that alter the way CPU context is stored, must be applied
much earlier in the boot sequence.

Introduce apply_boot_alternatives() to allow some alternatives to be
applied immediately after we detect the CPU features of the boot CPU.

Signed-off-by: Daniel Thompson &lt;daniel.thompson@linaro.org&gt;
[julien.thierry@arm.com: rename to fit new cpufeature framework better,
			 apply BOOT_SCOPE feature early in boot]
Signed-off-by: Julien Thierry &lt;julien.thierry@arm.com&gt;
Reviewed-by: Suzuki K Poulose &lt;suzuki.poulose@arm.com&gt;
Reviewed-by: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Cc: Will Deacon &lt;will.deacon@arm.com&gt;
Cc: Christoffer Dall &lt;christoffer.dall@arm.com&gt;
Cc: Suzuki K Poulose &lt;suzuki.poulose@arm.com&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: alternative: Allow alternative status checking per cpufeature</title>
<updated>2019-02-06T10:05:20+00:00</updated>
<author>
<name>Julien Thierry</name>
<email>julien.thierry@arm.com</email>
</author>
<published>2019-01-31T14:58:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e9ab7a2e333615497b3fc426c379c330230c2b50'/>
<id>e9ab7a2e333615497b3fc426c379c330230c2b50</id>
<content type='text'>
In preparation for the application of alternatives at different points
during the boot process, provide the possibility to check whether
alternatives for a feature of interest was already applied instead of
having a global boolean for all alternatives.

Make VHE enablement code check for the VHE feature instead of considering
all alternatives.

Signed-off-by: Julien Thierry &lt;julien.thierry@arm.com&gt;
Acked-by: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Cc: Will Deacon &lt;will.deacon@arm.com&gt;
Cc: Suzuki K Poulose &lt;suzuki.poulose@arm.com&gt;
Cc: Marc Zyngier &lt;Marc.Zyngier@arm.com&gt;
Cc: Christoffer Dall &lt;Christoffer.Dall@arm.com&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In preparation for the application of alternatives at different points
during the boot process, provide the possibility to check whether
alternatives for a feature of interest was already applied instead of
having a global boolean for all alternatives.

Make VHE enablement code check for the VHE feature instead of considering
all alternatives.

Signed-off-by: Julien Thierry &lt;julien.thierry@arm.com&gt;
Acked-by: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Cc: Will Deacon &lt;will.deacon@arm.com&gt;
Cc: Suzuki K Poulose &lt;suzuki.poulose@arm.com&gt;
Cc: Marc Zyngier &lt;Marc.Zyngier@arm.com&gt;
Cc: Christoffer Dall &lt;Christoffer.Dall@arm.com&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: alternative: Use true and false for boolean values</title>
<updated>2018-08-08T10:20:54+00:00</updated>
<author>
<name>Gustavo A. R. Silva</name>
<email>gustavo@embeddedor.com</email>
</author>
<published>2018-08-07T23:59:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=3c4d9137eefecf273a520d392071ffc9df0a9a7a'/>
<id>3c4d9137eefecf273a520d392071ffc9df0a9a7a</id>
<content type='text'>
Return statements in functions returning bool should use true or false
instead of an integer value. This code was detected with the help of
Coccinelle.

Signed-off-by: Gustavo A. R. Silva &lt;gustavo@embeddedor.com&gt;
Signed-off-by: Will Deacon &lt;will.deacon@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Return statements in functions returning bool should use true or false
instead of an integer value. This code was detected with the help of
Coccinelle.

Signed-off-by: Gustavo A. R. Silva &lt;gustavo@embeddedor.com&gt;
Signed-off-by: Will Deacon &lt;will.deacon@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: Avoid flush_icache_range() in alternatives patching code</title>
<updated>2018-06-27T17:21:53+00:00</updated>
<author>
<name>Will Deacon</name>
<email>will.deacon@arm.com</email>
</author>
<published>2018-06-22T08:31:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=429388682dc266e7a693f9c27e3aabd341d55343'/>
<id>429388682dc266e7a693f9c27e3aabd341d55343</id>
<content type='text'>
The implementation of flush_icache_range() includes instruction sequences
which are themselves patched at runtime, so it is not safe to call from
the patching framework.

This patch reworks the alternatives cache-flushing code so that it rolls
its own internal D-cache maintenance using DC CIVAC before invalidating
the entire I-cache after all alternatives have been applied at boot.
Modules don't cause any issues, since flush_icache_range() is safe to
call by the time they are loaded.

Acked-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Reported-by: Rohit Khanna &lt;rokhanna@nvidia.com&gt;
Cc: Alexander Van Brunt &lt;avanbrunt@nvidia.com&gt;
Signed-off-by: Will Deacon &lt;will.deacon@arm.com&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The implementation of flush_icache_range() includes instruction sequences
which are themselves patched at runtime, so it is not safe to call from
the patching framework.

This patch reworks the alternatives cache-flushing code so that it rolls
its own internal D-cache maintenance using DC CIVAC before invalidating
the entire I-cache after all alternatives have been applied at boot.
Modules don't cause any issues, since flush_icache_range() is safe to
call by the time they are loaded.

Acked-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Reported-by: Rohit Khanna &lt;rokhanna@nvidia.com&gt;
Cc: Alexander Van Brunt &lt;avanbrunt@nvidia.com&gt;
Signed-off-by: Will Deacon &lt;will.deacon@arm.com&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: alternatives: Add dynamic patching feature</title>
<updated>2018-03-19T13:03:17+00:00</updated>
<author>
<name>Marc Zyngier</name>
<email>marc.zyngier@arm.com</email>
</author>
<published>2017-12-03T12:02:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=dea5e2a4c5bcf196f879a66cebdcca07793e8ba4'/>
<id>dea5e2a4c5bcf196f879a66cebdcca07793e8ba4</id>
<content type='text'>
We've so far relied on a patching infrastructure that only gave us
a single alternative, without any way to provide a range of potential
replacement instructions. For a single feature, this is an all or
nothing thing.

It would be interesting to have a more flexible grained way of patching
the kernel though, where we could dynamically tune the code that gets
injected.

In order to achive this, let's introduce a new form of dynamic patching,
assiciating a callback to a patching site. This callback gets source and
target locations of the patching request, as well as the number of
instructions to be patched.

Dynamic patching is declared with the new ALTERNATIVE_CB and alternative_cb
directives:

	asm volatile(ALTERNATIVE_CB("mov %0, #0\n", callback)
		     : "r" (v));
or
	alternative_cb callback
		mov	x0, #0
	alternative_cb_end

where callback is the C function computing the alternative.

Reviewed-by: Christoffer Dall &lt;christoffer.dall@linaro.org&gt;
Reviewed-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Signed-off-by: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
We've so far relied on a patching infrastructure that only gave us
a single alternative, without any way to provide a range of potential
replacement instructions. For a single feature, this is an all or
nothing thing.

It would be interesting to have a more flexible grained way of patching
the kernel though, where we could dynamically tune the code that gets
injected.

In order to achive this, let's introduce a new form of dynamic patching,
assiciating a callback to a patching site. This callback gets source and
target locations of the patching request, as well as the number of
instructions to be patched.

Dynamic patching is declared with the new ALTERNATIVE_CB and alternative_cb
directives:

	asm volatile(ALTERNATIVE_CB("mov %0, #0\n", callback)
		     : "r" (v));
or
	alternative_cb callback
		mov	x0, #0
	alternative_cb_end

where callback is the C function computing the alternative.

Reviewed-by: Christoffer Dall &lt;christoffer.dall@linaro.org&gt;
Reviewed-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Signed-off-by: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: alternatives: use tpidr_el2 on VHE hosts</title>
<updated>2018-01-13T10:44:33+00:00</updated>
<author>
<name>James Morse</name>
<email>james.morse@arm.com</email>
</author>
<published>2018-01-08T15:38:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6d99b68933fbcf51f84fcbba49246ce1209ec193'/>
<id>6d99b68933fbcf51f84fcbba49246ce1209ec193</id>
<content type='text'>
Now that KVM uses tpidr_el2 in the same way as Linux's cpu_offset in
tpidr_el1, merge the two. This saves KVM from save/restoring tpidr_el1
on VHE hosts, and allows future code to blindly access per-cpu variables
without triggering world-switch.

Signed-off-by: James Morse &lt;james.morse@arm.com&gt;
Reviewed-by: Christoffer Dall &lt;cdall@linaro.org&gt;
Reviewed-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Now that KVM uses tpidr_el2 in the same way as Linux's cpu_offset in
tpidr_el1, merge the two. This saves KVM from save/restoring tpidr_el1
on VHE hosts, and allows future code to blindly access per-cpu variables
without triggering world-switch.

Signed-off-by: James Morse &lt;james.morse@arm.com&gt;
Reviewed-by: Christoffer Dall &lt;cdall@linaro.org&gt;
Reviewed-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: fix endianness annotation for __apply_alternatives()/get_alt_insn()</title>
<updated>2017-06-29T15:32:43+00:00</updated>
<author>
<name>Luc Van Oostenryck</name>
<email>luc.vanoostenryck@gmail.com</email>
</author>
<published>2017-06-29T14:40:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=15ad6ace52039c7e39435c4d712d147126604a97'/>
<id>15ad6ace52039c7e39435c4d712d147126604a97</id>
<content type='text'>
get_alt_insn() is used to read and create ARM instructions, which
are always stored in memory in little-endian order. These values
are thus correctly converted to/from native order when processed
but the pointers used to hold the address of these instructions
are declared as for native order values.

Fix this by declaring the pointers as __le32* instead of u32* and
make the few appropriate needed changes like removing the unneeded
cast '(u32*)' in front of __ALT_PTR()'s definition.

Signed-off-by: Luc Van Oostenryck &lt;luc.vanoostenryck@gmail.com&gt;
Signed-off-by: Will Deacon &lt;will.deacon@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
get_alt_insn() is used to read and create ARM instructions, which
are always stored in memory in little-endian order. These values
are thus correctly converted to/from native order when processed
but the pointers used to hold the address of these instructions
are declared as for native order values.

Fix this by declaring the pointers as __le32* instead of u32* and
make the few appropriate needed changes like removing the unneeded
cast '(u32*)' in front of __ALT_PTR()'s definition.

Signed-off-by: Luc Van Oostenryck &lt;luc.vanoostenryck@gmail.com&gt;
Signed-off-by: Will Deacon &lt;will.deacon@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: alternatives: apply boot time fixups via the linear mapping</title>
<updated>2017-03-23T13:54:19+00:00</updated>
<author>
<name>Ard Biesheuvel</name>
<email>ard.biesheuvel@linaro.org</email>
</author>
<published>2017-03-09T20:52:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5ea5306c3235a157f06040c59730b1133115ed26'/>
<id>5ea5306c3235a157f06040c59730b1133115ed26</id>
<content type='text'>
One important rule of thumb when desiging a secure software system is
that memory should never be writable and executable at the same time.
We mostly adhere to this rule in the kernel, except at boot time, when
regions may be mapped RWX until after we are done applying alternatives
or making other one-off changes.

For the alternative patching, we can improve the situation by applying
the fixups via the linear mapping, which is never mapped with executable
permissions. So map the linear alias of .text with RW- permissions
initially, and remove the write permissions as soon as alternative
patching has completed.

Reviewed-by: Laura Abbott &lt;labbott@redhat.com&gt;
Reviewed-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Tested-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Signed-off-by: Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
One important rule of thumb when desiging a secure software system is
that memory should never be writable and executable at the same time.
We mostly adhere to this rule in the kernel, except at boot time, when
regions may be mapped RWX until after we are done applying alternatives
or making other one-off changes.

For the alternative patching, we can improve the situation by applying
the fixups via the linear mapping, which is never mapped with executable
permissions. So map the linear alias of .text with RW- permissions
initially, and remove the write permissions as soon as alternative
patching has completed.

Reviewed-by: Laura Abbott &lt;labbott@redhat.com&gt;
Reviewed-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Tested-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Signed-off-by: Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: alternative: Add support for patching adrp instructions</title>
<updated>2016-09-09T14:03:28+00:00</updated>
<author>
<name>Suzuki K Poulose</name>
<email>suzuki.poulose@arm.com</email>
</author>
<published>2016-09-09T13:07:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c831b2ae257853ecd36ea4f7d788bf0665e4cf89'/>
<id>c831b2ae257853ecd36ea4f7d788bf0665e4cf89</id>
<content type='text'>
adrp uses PC-relative address offset to a page (of 4K size) of
a symbol. If it appears in an alternative code patched in, we
should adjust the offset to reflect the address where it will
be run from. This patch adds support for fixing the offset
for adrp instructions.

Cc: Will Deacon &lt;will.deacon@arm.com&gt;
Cc: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Cc: Andre Przywara &lt;andre.przywara@arm.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Signed-off-by: Suzuki K Poulose &lt;suzuki.poulose@arm.com&gt;
Signed-off-by: Will Deacon &lt;will.deacon@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
adrp uses PC-relative address offset to a page (of 4K size) of
a symbol. If it appears in an alternative code patched in, we
should adjust the offset to reflect the address where it will
be run from. This patch adds support for fixing the offset
for adrp instructions.

Cc: Will Deacon &lt;will.deacon@arm.com&gt;
Cc: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Cc: Andre Przywara &lt;andre.przywara@arm.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Signed-off-by: Suzuki K Poulose &lt;suzuki.poulose@arm.com&gt;
Signed-off-by: Will Deacon &lt;will.deacon@arm.com&gt;
</pre>
</div>
</content>
</entry>
</feed>
