<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/arch/s390/boot, branch v6.12</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge tag 's390-6.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux</title>
<updated>2024-09-21T16:02:54+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2024-09-21T16:02:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=1ec6d097897a35dfb55c4c31fc8633cf5be46497'/>
<id>1ec6d097897a35dfb55c4c31fc8633cf5be46497</id>
<content type='text'>
Pull s390 updates from Vasily Gorbik:

 - Optimize ftrace and kprobes code patching and avoid stop machine for
   kprobes if sequential instruction fetching facility is available

 - Add hiperdispatch feature to dynamically adjust CPU capacity in
   vertical polarization to improve scheduling efficiency and overall
   performance. Also add infrastructure for handling warning track
   interrupts (WTI), allowing for graceful CPU preemption

 - Rework crypto code pkey module and split it into separate,
   independent modules for sysfs, PCKMO, CCA, and EP11, allowing modules
   to load only when the relevant hardware is available

 - Add hardware acceleration for HMAC modes and the full AES-XTS cipher,
   utilizing message-security assist extensions (MSA) 10 and 11. It
   introduces new shash implementations for HMAC-SHA224/256/384/512 and
   registers the hardware-accelerated AES-XTS cipher as the preferred
   option. Also add clear key token support

 - Add MSA 10 and 11 processor activity instrumentation counters to perf
   and update PAI Extension 1 NNPA counters

 - Cleanup cpu sampling facility code and rework debug/WARN_ON_ONCE
   statements

 - Add support for SHA3 performance enhancements introduced with MSA 12

 - Add support for the query authentication information feature of MSA
   13 and introduce the KDSA CPACF instruction. Provide query and query
   authentication information in sysfs, enabling tools like cpacfinfo to
   present this data in a human-readable form

 - Update kernel disassembler instructions

 - Always enable EXPOLINE_EXTERN if supported by the compiler to ensure
   kpatch compatibility

 - Add missing warning handling and relocated lowcore support to the
   early program check handler

 - Optimize ftrace_return_address() and avoid calling unwinder

 - Make modules use kernel ftrace trampolines

 - Strip relocs from the final vmlinux ELF file to make it roughly 2
   times smaller

 - Dump register contents and call trace for early crashes to the
   console

 - Generate ptdump address marker array dynamically

 - Fix rcu_sched stalls that might occur when adding or removing large
   amounts of pages at once to or from the CMM balloon

 - Fix deadlock caused by recursive lock of the AP bus scan mutex

 - Unify sync and async register save areas in entry code

 - Cleanup debug prints in crypto code

 - Various cleanup and sanitizing patches for the decompressor

 - Various small ftrace cleanups

* tag 's390-6.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (84 commits)
  s390/crypto: Display Query and Query Authentication Information in sysfs
  s390/crypto: Add Support for Query Authentication Information
  s390/crypto: Rework RRE and RRF CPACF inline functions
  s390/crypto: Add KDSA CPACF Instruction
  s390/disassembler: Remove duplicate instruction format RSY_RDRU
  s390/boot: Move boot_printk() code to own file
  s390/boot: Use boot_printk() instead of sclp_early_printk()
  s390/boot: Rename decompressor_printk() to boot_printk()
  s390/boot: Compile all files with the same march flag
  s390: Use MARCH_HAS_*_FEATURES defines
  s390: Provide MARCH_HAS_*_FEATURES defines
  s390/facility: Disable compile time optimization for decompressor code
  s390/boot: Increase minimum architecture to z10
  s390/als: Remove obsolete comment
  s390/sha3: Fix SHA3 selftests failures
  s390/pkey: Add AES xts and HMAC clear key token support
  s390/cpacf: Add MSA 10 and 11 new PCKMO functions
  s390/mm: Add cond_resched() to cmm_alloc/free_pages()
  s390/pai_ext: Update PAI extension 1 counters
  s390/pai_crypto: Add support for MSA 10 and 11 pai counters
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull s390 updates from Vasily Gorbik:

 - Optimize ftrace and kprobes code patching and avoid stop machine for
   kprobes if sequential instruction fetching facility is available

 - Add hiperdispatch feature to dynamically adjust CPU capacity in
   vertical polarization to improve scheduling efficiency and overall
   performance. Also add infrastructure for handling warning track
   interrupts (WTI), allowing for graceful CPU preemption

 - Rework crypto code pkey module and split it into separate,
   independent modules for sysfs, PCKMO, CCA, and EP11, allowing modules
   to load only when the relevant hardware is available

 - Add hardware acceleration for HMAC modes and the full AES-XTS cipher,
   utilizing message-security assist extensions (MSA) 10 and 11. It
   introduces new shash implementations for HMAC-SHA224/256/384/512 and
   registers the hardware-accelerated AES-XTS cipher as the preferred
   option. Also add clear key token support

 - Add MSA 10 and 11 processor activity instrumentation counters to perf
   and update PAI Extension 1 NNPA counters

 - Cleanup cpu sampling facility code and rework debug/WARN_ON_ONCE
   statements

 - Add support for SHA3 performance enhancements introduced with MSA 12

 - Add support for the query authentication information feature of MSA
   13 and introduce the KDSA CPACF instruction. Provide query and query
   authentication information in sysfs, enabling tools like cpacfinfo to
   present this data in a human-readable form

 - Update kernel disassembler instructions

 - Always enable EXPOLINE_EXTERN if supported by the compiler to ensure
   kpatch compatibility

 - Add missing warning handling and relocated lowcore support to the
   early program check handler

 - Optimize ftrace_return_address() and avoid calling unwinder

 - Make modules use kernel ftrace trampolines

 - Strip relocs from the final vmlinux ELF file to make it roughly 2
   times smaller

 - Dump register contents and call trace for early crashes to the
   console

 - Generate ptdump address marker array dynamically

 - Fix rcu_sched stalls that might occur when adding or removing large
   amounts of pages at once to or from the CMM balloon

 - Fix deadlock caused by recursive lock of the AP bus scan mutex

 - Unify sync and async register save areas in entry code

 - Cleanup debug prints in crypto code

 - Various cleanup and sanitizing patches for the decompressor

 - Various small ftrace cleanups

* tag 's390-6.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (84 commits)
  s390/crypto: Display Query and Query Authentication Information in sysfs
  s390/crypto: Add Support for Query Authentication Information
  s390/crypto: Rework RRE and RRF CPACF inline functions
  s390/crypto: Add KDSA CPACF Instruction
  s390/disassembler: Remove duplicate instruction format RSY_RDRU
  s390/boot: Move boot_printk() code to own file
  s390/boot: Use boot_printk() instead of sclp_early_printk()
  s390/boot: Rename decompressor_printk() to boot_printk()
  s390/boot: Compile all files with the same march flag
  s390: Use MARCH_HAS_*_FEATURES defines
  s390: Provide MARCH_HAS_*_FEATURES defines
  s390/facility: Disable compile time optimization for decompressor code
  s390/boot: Increase minimum architecture to z10
  s390/als: Remove obsolete comment
  s390/sha3: Fix SHA3 selftests failures
  s390/pkey: Add AES xts and HMAC clear key token support
  s390/cpacf: Add MSA 10 and 11 new PCKMO functions
  s390/mm: Add cond_resched() to cmm_alloc/free_pages()
  s390/pai_ext: Update PAI extension 1 counters
  s390/pai_crypto: Add support for MSA 10 and 11 pai counters
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>s390/boot: Move boot_printk() code to own file</title>
<updated>2024-09-07T15:12:43+00:00</updated>
<author>
<name>Heiko Carstens</name>
<email>hca@linux.ibm.com</email>
</author>
<published>2024-09-04T09:39:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=5c9a274202ca144764e98d4032fed76693e8cfc6'/>
<id>5c9a274202ca144764e98d4032fed76693e8cfc6</id>
<content type='text'>
Keep the printk code separate from the program check code and move
boot_printk() and helper functions to own printk.c file.

Reviewed-by: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Signed-off-by: Heiko Carstens &lt;hca@linux.ibm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Keep the printk code separate from the program check code and move
boot_printk() and helper functions to own printk.c file.

Reviewed-by: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Signed-off-by: Heiko Carstens &lt;hca@linux.ibm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>s390/boot: Use boot_printk() instead of sclp_early_printk()</title>
<updated>2024-09-07T15:12:43+00:00</updated>
<author>
<name>Heiko Carstens</name>
<email>hca@linux.ibm.com</email>
</author>
<published>2024-09-04T09:39:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=dc7155550730dfab3b7cc59dfbf0d8c84ac67bf0'/>
<id>dc7155550730dfab3b7cc59dfbf0d8c84ac67bf0</id>
<content type='text'>
Consistently use boot_printk() everywhere instead of sclp_early_printk() at
some places. For some places it was required (e.g. als.c), in order to stay
in code compiled for the same architecture level, for other places it is
not obvious why sclp_early_printk() was used instead of
decompressor_printk().

Given that the whole decompressor code is compiled for the same
architecture level, there is no requirement left to use different
printk functions.

Reviewed-by: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Signed-off-by: Heiko Carstens &lt;hca@linux.ibm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Consistently use boot_printk() everywhere instead of sclp_early_printk() at
some places. For some places it was required (e.g. als.c), in order to stay
in code compiled for the same architecture level, for other places it is
not obvious why sclp_early_printk() was used instead of
decompressor_printk().

Given that the whole decompressor code is compiled for the same
architecture level, there is no requirement left to use different
printk functions.

Reviewed-by: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Signed-off-by: Heiko Carstens &lt;hca@linux.ibm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>s390/boot: Rename decompressor_printk() to boot_printk()</title>
<updated>2024-09-07T15:12:42+00:00</updated>
<author>
<name>Heiko Carstens</name>
<email>hca@linux.ibm.com</email>
</author>
<published>2024-09-04T09:39:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=bfda6108144628581ee50a127bb616cf097b1c7c'/>
<id>bfda6108144628581ee50a127bb616cf097b1c7c</id>
<content type='text'>
Rename decompressor_printk() to boot_printk() just to have a shorter
function name, which also makes the code more readable.

Reviewed-by: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Signed-off-by: Heiko Carstens &lt;hca@linux.ibm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Rename decompressor_printk() to boot_printk() just to have a shorter
function name, which also makes the code more readable.

Reviewed-by: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Signed-off-by: Heiko Carstens &lt;hca@linux.ibm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>s390/boot: Compile all files with the same march flag</title>
<updated>2024-09-07T15:12:42+00:00</updated>
<author>
<name>Heiko Carstens</name>
<email>hca@linux.ibm.com</email>
</author>
<published>2024-09-04T09:39:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=fccb175bc89a0d37e3ff513bb6bf1f73b3a48950'/>
<id>fccb175bc89a0d37e3ff513bb6bf1f73b3a48950</id>
<content type='text'>
Only a couple of files of the decompressor are compiled with the
minimum architecture level. This is problematic for potential function
calls between compile units, especially if a target function is within
a compile until compiled for a higher architecture level, since that
may lead to an unexpected operation exception.

Therefore compile all files of the decompressor for the same (minimum)
architecture level.

Reviewed-by: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Signed-off-by: Heiko Carstens &lt;hca@linux.ibm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Only a couple of files of the decompressor are compiled with the
minimum architecture level. This is problematic for potential function
calls between compile units, especially if a target function is within
a compile until compiled for a higher architecture level, since that
may lead to an unexpected operation exception.

Therefore compile all files of the decompressor for the same (minimum)
architecture level.

Reviewed-by: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Signed-off-by: Heiko Carstens &lt;hca@linux.ibm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>s390/boot: Increase minimum architecture to z10</title>
<updated>2024-09-07T15:12:42+00:00</updated>
<author>
<name>Heiko Carstens</name>
<email>hca@linux.ibm.com</email>
</author>
<published>2024-09-04T09:39:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=db545f5387472176cf1e7df76fe97a4f56b7158d'/>
<id>db545f5387472176cf1e7df76fe97a4f56b7158d</id>
<content type='text'>
The decompressor code is partially compiled with march=z900 so it is
possible to print an error message in case a kernel is booted on a
machine which misses facilities to execute the kernel.

Given that the decompressor code also includes header files from the
core kernel this causes problems for inline assemblies and other code
where the minimum assumed architecture level is set to z10 in the
meantime. If such code is also used in the decompressor (e.g. inline
functions) z900 support must be implemented again.

In order to avoid this and to keep things simple just raise the
minimum architecture level to z10 for the decompressor just like for
the kernel.

Reviewed-by: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Signed-off-by: Heiko Carstens &lt;hca@linux.ibm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The decompressor code is partially compiled with march=z900 so it is
possible to print an error message in case a kernel is booted on a
machine which misses facilities to execute the kernel.

Given that the decompressor code also includes header files from the
core kernel this causes problems for inline assemblies and other code
where the minimum assumed architecture level is set to z10 in the
meantime. If such code is also used in the decompressor (e.g. inline
functions) z900 support must be implemented again.

In order to avoid this and to keep things simple just raise the
minimum architecture level to z10 for the decompressor just like for
the kernel.

Reviewed-by: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Signed-off-by: Heiko Carstens &lt;hca@linux.ibm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>s390/als: Remove obsolete comment</title>
<updated>2024-09-07T15:12:41+00:00</updated>
<author>
<name>Heiko Carstens</name>
<email>hca@linux.ibm.com</email>
</author>
<published>2024-09-04T09:39:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=6fa7aea6a9fc8eb49d879ac66bf27460e70c83b3'/>
<id>6fa7aea6a9fc8eb49d879ac66bf27460e70c83b3</id>
<content type='text'>
The bss section of the decompressor is part of the compressed kernel image
since commit 980d5f9ab36b ("s390/boot: enable .bss section for compressed
kernel").

Remove a now incorrect comment that states that the bss section must not be
accessed.

Reviewed-by: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Signed-off-by: Heiko Carstens &lt;hca@linux.ibm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The bss section of the decompressor is part of the compressed kernel image
since commit 980d5f9ab36b ("s390/boot: enable .bss section for compressed
kernel").

Remove a now incorrect comment that states that the bss section must not be
accessed.

Reviewed-by: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Signed-off-by: Heiko Carstens &lt;hca@linux.ibm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>s390/entry: Unify save_area_sync and save_area_async</title>
<updated>2024-08-29T20:56:34+00:00</updated>
<author>
<name>Sven Schnelle</name>
<email>svens@linux.ibm.com</email>
</author>
<published>2024-08-28T11:50:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=ee3daf7c05e70a0b88723ceb18587aed75716729'/>
<id>ee3daf7c05e70a0b88723ceb18587aed75716729</id>
<content type='text'>
In the past two save areas existed because interrupt handlers
and system call / program check handlers where entered with
interrupts enabled. To prevent a handler from overwriting the
save areas from the previous handler, interrupts used the async
save area, while system call and program check handler used the
sync save area.

Since the removal of critical section cleanup from entry.S, handlers are
entered with interrupts disabled. When the interrupts are re-enabled,
the save area is no longer need. Therefore merge both save areas into one.

Reviewed-by: Heiko Carstens &lt;hca@linux.ibm.com&gt;
Reviewed-by: Alexander Gordeev &lt;agordeev@linux.ibm.com&gt;
Signed-off-by: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Signed-off-by: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In the past two save areas existed because interrupt handlers
and system call / program check handlers where entered with
interrupts enabled. To prevent a handler from overwriting the
save areas from the previous handler, interrupts used the async
save area, while system call and program check handler used the
sync save area.

Since the removal of critical section cleanup from entry.S, handlers are
entered with interrupts disabled. When the interrupts are re-enabled,
the save area is no longer need. Therefore merge both save areas into one.

Reviewed-by: Heiko Carstens &lt;hca@linux.ibm.com&gt;
Reviewed-by: Alexander Gordeev &lt;agordeev@linux.ibm.com&gt;
Signed-off-by: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Signed-off-by: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>s390/build: Avoid relocation information in final vmlinux</title>
<updated>2024-08-27T18:16:48+00:00</updated>
<author>
<name>Jens Remus</name>
<email>jremus@linux.ibm.com</email>
</author>
<published>2024-08-22T15:30:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=57216cc985b34c4cd6107a15fb04ca881465176d'/>
<id>57216cc985b34c4cd6107a15fb04ca881465176d</id>
<content type='text'>
Since commit 778666df60f0 ("s390: compile relocatable kernel without
-fPIE") the kernel vmlinux ELF file is linked with --emit-relocs to
preserve all relocations, so that all absolute relocations can be
extracted using the 'relocs' tool to adjust them during boot.

Port and adapt Petr Pavlu's x86 commit 9d9173e9ceb6 ("x86/build: Avoid
relocation information in final vmlinux") to s390 to strip all
relocations from the final vmlinux ELF file to optimize its size.
Following is his original commit message with minor adaptions for s390:

The Linux build process on s390 roughly consists of compiling all input
files, statically linking them into a vmlinux ELF file, and then taking
and turning this file into an actual bzImage bootable file.

vmlinux has in this process two main purposes:
1) It is an intermediate build target on the way to produce the final
   bootable image.
2) It is a file that is expected to be used by debuggers and standard
   ELF tooling to work with the built kernel.

For the second purpose, a vmlinux file is typically collected by various
package build recipes, such as distribution spec files, including the
kernel's own tar-pkg target.

When building the kernel vmlinux contains also relocation information
produced by using the --emit-relocs linker option. This is utilized by
subsequent build steps to create relocs.S and produce a relocatable
image. However, the information is not needed by debuggers and other
standard ELF tooling.

The issue is then that the collected vmlinux file and hence distribution
packages end up unnecessarily large because of this extra data. The
following is a size comparison of vmlinux v6.10 with and without the
relocation information:

  | Configuration      | With relocs | Stripped relocs |
  | defconfig          |      696 MB |          320 MB |
  | -CONFIG_DEBUG_INFO |       48 MB |           32 MB |

Optimize a resulting vmlinux by adding a postlink step that splits the
relocation information into relocs.S and then strips it from the vmlinux
binary.

Reviewed-by: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Signed-off-by: Jens Remus &lt;jremus@linux.ibm.com&gt;
Signed-off-by: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Since commit 778666df60f0 ("s390: compile relocatable kernel without
-fPIE") the kernel vmlinux ELF file is linked with --emit-relocs to
preserve all relocations, so that all absolute relocations can be
extracted using the 'relocs' tool to adjust them during boot.

Port and adapt Petr Pavlu's x86 commit 9d9173e9ceb6 ("x86/build: Avoid
relocation information in final vmlinux") to s390 to strip all
relocations from the final vmlinux ELF file to optimize its size.
Following is his original commit message with minor adaptions for s390:

The Linux build process on s390 roughly consists of compiling all input
files, statically linking them into a vmlinux ELF file, and then taking
and turning this file into an actual bzImage bootable file.

vmlinux has in this process two main purposes:
1) It is an intermediate build target on the way to produce the final
   bootable image.
2) It is a file that is expected to be used by debuggers and standard
   ELF tooling to work with the built kernel.

For the second purpose, a vmlinux file is typically collected by various
package build recipes, such as distribution spec files, including the
kernel's own tar-pkg target.

When building the kernel vmlinux contains also relocation information
produced by using the --emit-relocs linker option. This is utilized by
subsequent build steps to create relocs.S and produce a relocatable
image. However, the information is not needed by debuggers and other
standard ELF tooling.

The issue is then that the collected vmlinux file and hence distribution
packages end up unnecessarily large because of this extra data. The
following is a size comparison of vmlinux v6.10 with and without the
relocation information:

  | Configuration      | With relocs | Stripped relocs |
  | defconfig          |      696 MB |          320 MB |
  | -CONFIG_DEBUG_INFO |       48 MB |           32 MB |

Optimize a resulting vmlinux by adding a postlink step that splits the
relocation information into relocs.S and then strips it from the vmlinux
binary.

Reviewed-by: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Signed-off-by: Jens Remus &lt;jremus@linux.ibm.com&gt;
Signed-off-by: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>s390/boot: Fix KASLR base offset off by __START_KERNEL bytes</title>
<updated>2024-08-22T17:24:13+00:00</updated>
<author>
<name>Alexander Gordeev</name>
<email>agordeev@linux.ibm.com</email>
</author>
<published>2024-08-21T16:55:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=1642285e511c2a40b14e87a41aa8feace6123036'/>
<id>1642285e511c2a40b14e87a41aa8feace6123036</id>
<content type='text'>
Symbol offsets to the KASLR base do not match symbol address in
the vmlinux image. That is the result of setting the KASLR base
to the beginning of .text section as result of an optimization.

Revert that optimization and allocate virtual memory for the
whole kernel image including __START_KERNEL bytes as per the
linker script. That allows keeping the semantics of the KASLR
base offset in sync with other architectures.

Rename __START_KERNEL to TEXT_OFFSET, since it represents the
offset of the .text section within the kernel image, rather than
a virtual address.

Still skip mapping TEXT_OFFSET bytes to save memory on pgtables
and provoke exceptions in case an attempt to access this area is
made, as no kernel symbol may reside there.

In case CONFIG_KASAN is enabled the location counter might exceed
the value of TEXT_OFFSET, while the decompressor linker script
forcefully resets it to TEXT_OFFSET, which leads to a sections
overlap link failure. Use MAX() expression to avoid that.

Reported-by: Omar Sandoval &lt;osandov@osandov.com&gt;
Closes: https://lore.kernel.org/linux-s390/ZnS8dycxhtXBZVky@telecaster.dhcp.thefacebook.com/
Fixes: 56b1069c40c7 ("s390/boot: Rework deployment of the kernel image")
Signed-off-by: Alexander Gordeev &lt;agordeev@linux.ibm.com&gt;
Acked-by: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Signed-off-by: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
</content>
<content type='xhtml'>
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<pre>
Symbol offsets to the KASLR base do not match symbol address in
the vmlinux image. That is the result of setting the KASLR base
to the beginning of .text section as result of an optimization.

Revert that optimization and allocate virtual memory for the
whole kernel image including __START_KERNEL bytes as per the
linker script. That allows keeping the semantics of the KASLR
base offset in sync with other architectures.

Rename __START_KERNEL to TEXT_OFFSET, since it represents the
offset of the .text section within the kernel image, rather than
a virtual address.

Still skip mapping TEXT_OFFSET bytes to save memory on pgtables
and provoke exceptions in case an attempt to access this area is
made, as no kernel symbol may reside there.

In case CONFIG_KASAN is enabled the location counter might exceed
the value of TEXT_OFFSET, while the decompressor linker script
forcefully resets it to TEXT_OFFSET, which leads to a sections
overlap link failure. Use MAX() expression to avoid that.

Reported-by: Omar Sandoval &lt;osandov@osandov.com&gt;
Closes: https://lore.kernel.org/linux-s390/ZnS8dycxhtXBZVky@telecaster.dhcp.thefacebook.com/
Fixes: 56b1069c40c7 ("s390/boot: Rework deployment of the kernel image")
Signed-off-by: Alexander Gordeev &lt;agordeev@linux.ibm.com&gt;
Acked-by: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Signed-off-by: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
</pre>
</div>
</content>
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