<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/firmware/efi, branch linux-5.8.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>efi/arm64: libstub: Deal gracefully with EFI_RNG_PROTOCOL failure</title>
<updated>2020-11-01T11:45:36+00:00</updated>
<author>
<name>Ard Biesheuvel</name>
<email>ardb@kernel.org</email>
</author>
<published>2020-09-26T08:52:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=8b23af0ef2f7ad76a3b0b734e06244e64f9bd829'/>
<id>8b23af0ef2f7ad76a3b0b734e06244e64f9bd829</id>
<content type='text'>
commit d32de9130f6c79533508e2c7879f18997bfbe2a0 upstream.

Currently, on arm64, we abort on any failure from efi_get_random_bytes()
other than EFI_NOT_FOUND when it comes to setting the physical seed for
KASLR, but ignore such failures when obtaining the seed for virtual
KASLR or for early seeding of the kernel's entropy pool via the config
table. This is inconsistent, and may lead to unexpected boot failures.

So let's permit any failure for the physical seed, and simply report
the error code if it does not equal EFI_NOT_FOUND.

Cc: &lt;stable@vger.kernel.org&gt; # v5.8+
Reported-by: Heinrich Schuchardt &lt;xypron.glpk@gmx.de&gt;
Signed-off-by: Ard Biesheuvel &lt;ardb@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 d32de9130f6c79533508e2c7879f18997bfbe2a0 upstream.

Currently, on arm64, we abort on any failure from efi_get_random_bytes()
other than EFI_NOT_FOUND when it comes to setting the physical seed for
KASLR, but ignore such failures when obtaining the seed for virtual
KASLR or for early seeding of the kernel's entropy pool via the config
table. This is inconsistent, and may lead to unexpected boot failures.

So let's permit any failure for the physical seed, and simply report
the error code if it does not equal EFI_NOT_FOUND.

Cc: &lt;stable@vger.kernel.org&gt; # v5.8+
Reported-by: Heinrich Schuchardt &lt;xypron.glpk@gmx.de&gt;
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>efi: efibc: check for efivars write capability</title>
<updated>2020-09-23T10:59:58+00:00</updated>
<author>
<name>Ard Biesheuvel</name>
<email>ardb@kernel.org</email>
</author>
<published>2020-09-15T15:12:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=abd90e56bcb30627d962469ac4fa85bef01440f5'/>
<id>abd90e56bcb30627d962469ac4fa85bef01440f5</id>
<content type='text'>
[ Upstream commit 46908326c6b801201f1e46f5ed0db6e85bef74ae ]

Branden reports that commit

  f88814cc2578c1 ("efi/efivars: Expose RT service availability via efivars abstraction")

regresses UEFI platforms that implement GetVariable but not SetVariable
when booting kernels that have EFIBC (bootloader control) enabled.

The reason is that EFIBC is a user of the efivars abstraction, which was
updated to permit users that rely only on the read capability, but not on
the write capability. EFIBC is in the latter category, so it has to check
explicitly whether efivars supports writes.

Fixes: f88814cc2578c1 ("efi/efivars: Expose RT service availability via efivars abstraction")
Tested-by: Branden Sherrell &lt;sherrellbc@gmail.com&gt;
Link: https://lore.kernel.org/linux-efi/AE217103-C96F-4AFC-8417-83EC11962004@gmail.com/
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 46908326c6b801201f1e46f5ed0db6e85bef74ae ]

Branden reports that commit

  f88814cc2578c1 ("efi/efivars: Expose RT service availability via efivars abstraction")

regresses UEFI platforms that implement GetVariable but not SetVariable
when booting kernels that have EFIBC (bootloader control) enabled.

The reason is that EFIBC is a user of the efivars abstraction, which was
updated to permit users that rely only on the read capability, but not on
the write capability. EFIBC is in the latter category, so it has to check
explicitly whether efivars supports writes.

Fixes: f88814cc2578c1 ("efi/efivars: Expose RT service availability via efivars abstraction")
Tested-by: Branden Sherrell &lt;sherrellbc@gmail.com&gt;
Link: https://lore.kernel.org/linux-efi/AE217103-C96F-4AFC-8417-83EC11962004@gmail.com/
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>test_firmware: Test platform fw loading on non-EFI systems</title>
<updated>2020-09-17T11:55:45+00:00</updated>
<author>
<name>Kees Cook</name>
<email>keescook@chromium.org</email>
</author>
<published>2020-09-09T22:53:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f17c2fe6ea89a007e72aed27d672d9e3c417d2b7'/>
<id>f17c2fe6ea89a007e72aed27d672d9e3c417d2b7</id>
<content type='text'>
commit baaabecfc80fad255f866563b53b8c7a3eec176e upstream.

On non-EFI systems, it wasn't possible to test the platform firmware
loader because it will have never set "checked_fw" during __init.
Instead, allow the test code to override this check. Additionally split
the declarations into a private symbol namespace so there is greater
enforcement of the symbol visibility.

Fixes: 548193cba2a7 ("test_firmware: add support for firmware_request_platform")
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook &lt;keescook@chromium.org&gt;
Acked-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Link: https://lore.kernel.org/r/20200909225354.3118328-1-keescook@chromium.org
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 baaabecfc80fad255f866563b53b8c7a3eec176e upstream.

On non-EFI systems, it wasn't possible to test the platform firmware
loader because it will have never set "checked_fw" during __init.
Instead, allow the test code to override this check. Additionally split
the declarations into a private symbol namespace so there is greater
enforcement of the symbol visibility.

Fixes: 548193cba2a7 ("test_firmware: add support for firmware_request_platform")
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook &lt;keescook@chromium.org&gt;
Acked-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Link: https://lore.kernel.org/r/20200909225354.3118328-1-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>efi/libstub: Handle unterminated cmdline</title>
<updated>2020-08-26T09:49:19+00:00</updated>
<author>
<name>Arvind Sankar</name>
<email>nivedita@alum.mit.edu</email>
</author>
<published>2020-08-13T18:58:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1f802ace4bd5a2762a2e8637f2ea1e3aa31fb0d5'/>
<id>1f802ace4bd5a2762a2e8637f2ea1e3aa31fb0d5</id>
<content type='text'>
commit 8a8a3237a78cbc0557f0eb16a89f16d616323e99 upstream.

Make the command line parsing more robust, by handling the case it is
not NUL-terminated.

Use strnlen instead of strlen, and make sure that the temporary copy is
NUL-terminated before parsing.

Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Arvind Sankar &lt;nivedita@alum.mit.edu&gt;
Link: https://lore.kernel.org/r/20200813185811.554051-4-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel &lt;ardb@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 8a8a3237a78cbc0557f0eb16a89f16d616323e99 upstream.

Make the command line parsing more robust, by handling the case it is
not NUL-terminated.

Use strnlen instead of strlen, and make sure that the temporary copy is
NUL-terminated before parsing.

Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Arvind Sankar &lt;nivedita@alum.mit.edu&gt;
Link: https://lore.kernel.org/r/20200813185811.554051-4-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>efi/libstub: Handle NULL cmdline</title>
<updated>2020-08-26T09:49:19+00:00</updated>
<author>
<name>Arvind Sankar</name>
<email>nivedita@alum.mit.edu</email>
</author>
<published>2020-07-29T19:33:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ca60a5eb83720d0eb425e6192723afa77ac86a73'/>
<id>ca60a5eb83720d0eb425e6192723afa77ac86a73</id>
<content type='text'>
commit a37ca6a2af9df2972372b918f09390c9303acfbd upstream.

Treat a NULL cmdline the same as empty. Although this is unlikely to
happen in practice, the x86 kernel entry does check for NULL cmdline and
handles it, so do it here as well.

Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Arvind Sankar &lt;nivedita@alum.mit.edu&gt;
Link: https://lore.kernel.org/r/20200729193300.598448-1-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel &lt;ardb@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 a37ca6a2af9df2972372b918f09390c9303acfbd upstream.

Treat a NULL cmdline the same as empty. Although this is unlikely to
happen in practice, the x86 kernel entry does check for NULL cmdline and
handles it, so do it here as well.

Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Arvind Sankar &lt;nivedita@alum.mit.edu&gt;
Link: https://lore.kernel.org/r/20200729193300.598448-1-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>efi/libstub: Stop parsing arguments at "--"</title>
<updated>2020-08-26T09:49:19+00:00</updated>
<author>
<name>Arvind Sankar</name>
<email>nivedita@alum.mit.edu</email>
</author>
<published>2020-07-25T15:59:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=3bff856ba44d73cf6b17a8232d7ce444a7f21907'/>
<id>3bff856ba44d73cf6b17a8232d7ce444a7f21907</id>
<content type='text'>
commit 1fd9717d75df68e3c3509b8e7b1138ca63472f88 upstream.

Arguments after "--" are arguments for init, not for the kernel.

Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Arvind Sankar &lt;nivedita@alum.mit.edu&gt;
Link: https://lore.kernel.org/r/20200725155916.1376773-1-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel &lt;ardb@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 1fd9717d75df68e3c3509b8e7b1138ca63472f88 upstream.

Arguments after "--" are arguments for init, not for the kernel.

Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Arvind Sankar &lt;nivedita@alum.mit.edu&gt;
Link: https://lore.kernel.org/r/20200725155916.1376773-1-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>efi: add missed destroy_workqueue when efisubsys_init fails</title>
<updated>2020-08-26T09:49:19+00:00</updated>
<author>
<name>Li Heng</name>
<email>liheng40@huawei.com</email>
</author>
<published>2020-07-20T07:22:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e6584124b9823151ef586d10dedf565ade50cea6'/>
<id>e6584124b9823151ef586d10dedf565ade50cea6</id>
<content type='text'>
commit 98086df8b70c06234a8f4290c46064e44dafa0ed upstream.

destroy_workqueue() should be called to destroy efi_rts_wq
when efisubsys_init() init resources fails.

Cc: &lt;stable@vger.kernel.org&gt;
Reported-by: Hulk Robot &lt;hulkci@huawei.com&gt;
Signed-off-by: Li Heng &lt;liheng40@huawei.com&gt;
Link: https://lore.kernel.org/r/1595229738-10087-1-git-send-email-liheng40@huawei.com
Signed-off-by: Ard Biesheuvel &lt;ardb@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 98086df8b70c06234a8f4290c46064e44dafa0ed upstream.

destroy_workqueue() should be called to destroy efi_rts_wq
when efisubsys_init() init resources fails.

Cc: &lt;stable@vger.kernel.org&gt;
Reported-by: Hulk Robot &lt;hulkci@huawei.com&gt;
Signed-off-by: Li Heng &lt;liheng40@huawei.com&gt;
Link: https://lore.kernel.org/r/1595229738-10087-1-git-send-email-liheng40@huawei.com
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'efi-urgent-2020-07-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into master</title>
<updated>2020-07-25T20:18:42+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2020-07-25T20:18:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=17baa442864254cb2aadf3a4d668c0f81d2f07c5'/>
<id>17baa442864254cb2aadf3a4d668c0f81d2f07c5</id>
<content type='text'>
Pull EFI fixes from Ingo Molnar:
 "Various EFI fixes:

   - Fix the layering violation in the use of the EFI runtime services
     availability mask in users of the 'efivars' abstraction

   - Revert build fix for GCC v4.8 which is no longer supported

   - Clean up some x86 EFI stub details, some of which are borderline
     bugs that copy around garbage into padding fields - let's fix these
     out of caution.

   - Fix build issues while working on RISC-V support

   - Avoid --whole-archive when linking the stub on arm64"

* tag 'efi-urgent-2020-07-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  efi: Revert "efi/x86: Fix build with gcc 4"
  efi/efivars: Expose RT service availability via efivars abstraction
  efi/libstub: Move the function prototypes to header file
  efi/libstub: Fix gcc error around __umoddi3 for 32 bit builds
  efi/libstub/arm64: link stub lib.a conditionally
  efi/x86: Only copy upto the end of setup_header
  efi/x86: Remove unused variables
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull EFI fixes from Ingo Molnar:
 "Various EFI fixes:

   - Fix the layering violation in the use of the EFI runtime services
     availability mask in users of the 'efivars' abstraction

   - Revert build fix for GCC v4.8 which is no longer supported

   - Clean up some x86 EFI stub details, some of which are borderline
     bugs that copy around garbage into padding fields - let's fix these
     out of caution.

   - Fix build issues while working on RISC-V support

   - Avoid --whole-archive when linking the stub on arm64"

* tag 'efi-urgent-2020-07-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  efi: Revert "efi/x86: Fix build with gcc 4"
  efi/efivars: Expose RT service availability via efivars abstraction
  efi/libstub: Move the function prototypes to header file
  efi/libstub: Fix gcc error around __umoddi3 for 32 bit builds
  efi/libstub/arm64: link stub lib.a conditionally
  efi/x86: Only copy upto the end of setup_header
  efi/x86: Remove unused variables
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux into master</title>
<updated>2020-07-17T22:27:52+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2020-07-17T22:27:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a570f4198906a88b959ddcc56ddabc634397e810'/>
<id>a570f4198906a88b959ddcc56ddabc634397e810</id>
<content type='text'>
Pull arm64 fixes from Will Deacon:
 "A batch of arm64 fixes.

  Although the diffstat is a bit larger than we'd usually have at this
  stage, a decent amount of it is the addition of comments describing
  our syscall tracing behaviour, and also a sweep across all the modular
  arm64 PMU drivers to make them rebust against unloading and unbinding.

  There are a couple of minor things kicking around at the moment (CPU
  errata and module PLTs for very large modules), but I'm not expecting
  any significant changes now for us in 5.8.

   - Fix kernel text addresses for relocatable images booting using EFI
     and with KASLR disabled so that they match the vmlinux ELF binary.

   - Fix unloading and unbinding of PMU driver modules.

   - Fix generic mmiowb() when writeX() is called from preemptible
     context (reported by the riscv folks).

   - Fix ptrace hardware single-step interactions with signal handlers,
     system calls and reverse debugging.

   - Fix reporting of 64-bit x0 register for 32-bit tasks via
     'perf_regs'.

   - Add comments describing syscall entry/exit tracing ABI"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  drivers/perf: Prevent forced unbinding of PMU drivers
  asm-generic/mmiowb: Allow mmiowb_set_pending() when preemptible()
  arm64: Use test_tsk_thread_flag() for checking TIF_SINGLESTEP
  arm64: ptrace: Use NO_SYSCALL instead of -1 in syscall_trace_enter()
  arm64: syscall: Expand the comment about ptrace and syscall(-1)
  arm64: ptrace: Add a comment describing our syscall entry/exit trap ABI
  arm64: compat: Ensure upper 32 bits of x0 are zero on syscall return
  arm64: ptrace: Override SPSR.SS when single-stepping is enabled
  arm64: ptrace: Consistently use pseudo-singlestep exceptions
  drivers/perf: Fix kernel panic when rmmod PMU modules during perf sampling
  efi/libstub/arm64: Retain 2MB kernel Image alignment if !KASLR
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull arm64 fixes from Will Deacon:
 "A batch of arm64 fixes.

  Although the diffstat is a bit larger than we'd usually have at this
  stage, a decent amount of it is the addition of comments describing
  our syscall tracing behaviour, and also a sweep across all the modular
  arm64 PMU drivers to make them rebust against unloading and unbinding.

  There are a couple of minor things kicking around at the moment (CPU
  errata and module PLTs for very large modules), but I'm not expecting
  any significant changes now for us in 5.8.

   - Fix kernel text addresses for relocatable images booting using EFI
     and with KASLR disabled so that they match the vmlinux ELF binary.

   - Fix unloading and unbinding of PMU driver modules.

   - Fix generic mmiowb() when writeX() is called from preemptible
     context (reported by the riscv folks).

   - Fix ptrace hardware single-step interactions with signal handlers,
     system calls and reverse debugging.

   - Fix reporting of 64-bit x0 register for 32-bit tasks via
     'perf_regs'.

   - Add comments describing syscall entry/exit tracing ABI"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  drivers/perf: Prevent forced unbinding of PMU drivers
  asm-generic/mmiowb: Allow mmiowb_set_pending() when preemptible()
  arm64: Use test_tsk_thread_flag() for checking TIF_SINGLESTEP
  arm64: ptrace: Use NO_SYSCALL instead of -1 in syscall_trace_enter()
  arm64: syscall: Expand the comment about ptrace and syscall(-1)
  arm64: ptrace: Add a comment describing our syscall entry/exit trap ABI
  arm64: compat: Ensure upper 32 bits of x0 are zero on syscall return
  arm64: ptrace: Override SPSR.SS when single-stepping is enabled
  arm64: ptrace: Consistently use pseudo-singlestep exceptions
  drivers/perf: Fix kernel panic when rmmod PMU modules during perf sampling
  efi/libstub/arm64: Retain 2MB kernel Image alignment if !KASLR
</pre>
</div>
</content>
</entry>
<entry>
<title>efi/libstub/arm64: Retain 2MB kernel Image alignment if !KASLR</title>
<updated>2020-07-13T13:08:07+00:00</updated>
<author>
<name>Will Deacon</name>
<email>will@kernel.org</email>
</author>
<published>2020-07-09T20:48:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7c116db24d944ff04a67c8bd89cb32c5cd0894ff'/>
<id>7c116db24d944ff04a67c8bd89cb32c5cd0894ff</id>
<content type='text'>
Since commit 82046702e288 ("efi/libstub/arm64: Replace 'preferred' offset
with alignment check"), loading a relocatable arm64 kernel at a physical
address which is not 2MB aligned and subsequently booting with EFI will
leave the Image in-place, relying on the kernel to relocate itself early
during boot. In conjunction with commit dd4bc6076587 ("arm64: warn on
incorrect placement of the kernel by the bootloader"), which enables
CONFIG_RELOCATABLE by default, this effectively means that entering an
arm64 kernel loaded at an alignment smaller than 2MB with EFI (e.g. using
QEMU) will result in silent relocation at runtime.

Unfortunately, this has a subtle but confusing affect for developers
trying to inspect the PC value during a crash and comparing it to the
symbol addresses in vmlinux using tools such as 'nm' or 'addr2line';
all text addresses will be displaced by a sub-2MB offset, resulting in
the wrong symbol being identified in many cases. Passing "nokaslr" on
the command line or disabling "CONFIG_RANDOMIZE_BASE" does not help,
since the EFI stub only copies the kernel Image to a 2MB boundary if it
is not relocatable.

Adjust the EFI stub for arm64 so that the minimum Image alignment is 2MB
unless KASLR is in use.

Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Marc Zyngier &lt;maz@kernel.org&gt;
Cc: David Brazdil &lt;dbrazdil@google.com&gt;
Acked-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Since commit 82046702e288 ("efi/libstub/arm64: Replace 'preferred' offset
with alignment check"), loading a relocatable arm64 kernel at a physical
address which is not 2MB aligned and subsequently booting with EFI will
leave the Image in-place, relying on the kernel to relocate itself early
during boot. In conjunction with commit dd4bc6076587 ("arm64: warn on
incorrect placement of the kernel by the bootloader"), which enables
CONFIG_RELOCATABLE by default, this effectively means that entering an
arm64 kernel loaded at an alignment smaller than 2MB with EFI (e.g. using
QEMU) will result in silent relocation at runtime.

Unfortunately, this has a subtle but confusing affect for developers
trying to inspect the PC value during a crash and comparing it to the
symbol addresses in vmlinux using tools such as 'nm' or 'addr2line';
all text addresses will be displaced by a sub-2MB offset, resulting in
the wrong symbol being identified in many cases. Passing "nokaslr" on
the command line or disabling "CONFIG_RANDOMIZE_BASE" does not help,
since the EFI stub only copies the kernel Image to a 2MB boundary if it
is not relocatable.

Adjust the EFI stub for arm64 so that the minimum Image alignment is 2MB
unless KASLR is in use.

Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Marc Zyngier &lt;maz@kernel.org&gt;
Cc: David Brazdil &lt;dbrazdil@google.com&gt;
Acked-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
</pre>
</div>
</content>
</entry>
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