Add documentation which describes what the fpu helper functions are
good for, and why they should be used.
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

Move, rename, and merge the fpu and vx header files. This way fpu header
files have a consistent naming scheme (fpu*.h).

Also get rid of the fpu subdirectory and move header files to asm
directory, so that all fpu and vx header files can be found at the same
location.

Merge internal.h header file into other header files, since the internal
helpers are used at many locations. so those helper functions are really
not internal.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

Address various checkpatch warnings, adjust whitespace, and try to increase
readability. This is just preparation, in order to avoid that subsequent
patches contain any distracting drive-by coding style changes.
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

Use KERNEL_VXR_LOW instead of KERNEL_VXR_V0V7 for configurations without
vector registers in order to decide if floating point registers need to be
saved and restored.

Kernel FPU areas which use floating point registers are supposed to use the
KERNEL_FPR mask, however users may also open-code this and specify
KERNEL_VXR_V0V7 and/or KERNEL_VXR_V8V15. If only KERNEL_VXR_V8V15 is
specified floating point registers wouldn't be saved and restored. Improve
this and check for both bits.

There are currently no users where this would fix a bug.
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

Remove the historic machine check handler code which validates registers.
Registers are automatically validated as part of the machine check handling
sequence (see Principles of Operation, Machine-Check Handling chapter,
Validation).
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

The v1, v2, v3, and v4 parameters of the RXB macro are a bit misleading,
since the reader can assume that the parameters always correlate with the
instructions format fields V1, V2, V3, and V4 as defined in the Principles
of Operation.

This is not the case for a couple of instructions, therefore improve the
description of the macro.

Suggested by Jens Remus, who also provided the improved description.
Suggested-by: Jens Remus <jremus@linux.ibm.com>
Reviewed-by: Jens Remus <jremus@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

The VLGV macro generates the VLGV instruction and has a vr parameter which
correlates to the V3 vector register field of the instruction (bits 12-15).
Due to its position in the VRS-c instruction format of the VLGV
instruction, this field correlates to the second bit of the RXB byte of the
instruction (see Principles of Operation, Chapter "Vector Overview and
Support Instructions").

Within the VLGV macro the MRXBOPC macro is used to generate the RXB field
of the instruction. The usage of the MRXBOPC macro is incorrect, since the
vector register number is passed as third parameter (which correlates to
the first bit of the RXB byte), while it should be passed as fourth
parameter (second bit of the RXB byte). In result an incorrect instruction
would be generated if the VLGV macro would be used for vector register
numbers larger than 15.

Fix this and pass the vector register number as fourth parameter.

Currently there are no users within the kernel which use the macro in a way
that broken code would be generated.
Reviewed-by: Jens Remus <jremus@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

This patch introduces dynamic debug hexdump invocation
possibilities to be able to:
- dump an CCA or EP11 CPRB request as early as possible
  when received via ioctl from userspace but after the
  ap message has been collected together.
- dump an CCA or EP11 CPRB reply short before it is
  transferred via ioctl into userspace.
Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Reviewed-by: Holger Dengler <dengler@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

This patch introduces two dynamic debug hexdump
invocation possibilities to be able to a) dump an
AP message immediately before it goes into the
firmware queue and b) dump a fresh from the
firmware queue received AP message.
Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Reviewed-by: Holger Dengler <dengler@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

This patch replaces all the s390 debug feature calls with
debug level by dynamic debug calls pr_debug. These calls
are much more flexible and each single invocation can get
enabled/disabled at runtime wheres the s390 debug feature
debug calls have only one knob - enable or disable all in
one bunch.

This patch follows a similar change for the AP bus and
zcrypt device driver code. All this code uses dynamic
debugging with pr_debug and friends for emitting debug
traces now.
Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Reviewed-by: Holger Dengler <dengler@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

Cleanup and harmonize the s390 debug feature calls
and defines for the pkey module to be similar to
the debug feature as it is used in the zcrypt device
driver and AP bus.

More or less only renaming but no functional changes.
Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Reviewed-by: Holger Dengler <dengler@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

This patch replaces all the s390 debug feature calls with
debug level by dynamic debug calls pr_debug. These calls
are much more flexible and each single invocation can get
enabled/disabled at runtime wheres the s390 debug feature
debug calls have only one knob - enable or disable all in
one bunch. The benefit is especially significant with
high frequency called functions like the AP bus scan. In
most debugging scenarios you don't want and need them, but
sometimes it is crucial to know exactly when and how long
the AP bus scan took.
Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Reviewed-by: Holger Dengler <dengler@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

This patch harmonizes the calls and defines around the
s390 debug feature as it is used in the AP bus and
zcrypt device driver code.

More or less cleanup and renaming, no functional changes.
Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Reviewed-by: Holger Dengler <dengler@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

Fix virtual vs physical address confusion. This does not fix a bug
since virtual and physical address spaces are currently the same.

/proc/iomem should report the physical address ranges, so use __pa_symbol()
for resource registration, similar to other architectures.
Signed-off-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

When building 'ARCH=s390 defconfig compat.config' with GCC and
LD=ld.lld, there is an error when attempting to link the compat vDSO:

  ld.lld: error: unknown emulation: elf_s390
  make[4]: *** [arch/s390/kernel/vdso32/Makefile:48: arch/s390/kernel/vdso32/vdso32.so.dbg] Error 1

Much like clang, ld.lld only supports the 64-bit s390 emulation. Add a
dependency on not using LLD to CONFIG_COMPAT to avoid breaking the build
with this toolchain combination.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20240214-s390-compat-lld-dep-v1-1-abf1f4b5e514@kernel.orgSigned-off-by: Heiko Carstens <hca@linux.ibm.com>

When linking vdso64.so.dbg with ld.lld, there is a warning about not
finding _start for the starting address:

  ld.lld: warning: cannot find entry symbol _start; not setting start address

Fix this by removing the unused ENTRY in both vdso linker scripts. See
commit e2471728 ("powerpc/vdso: Remove unused ENTRY in linker
scripts"), which solved the same problem for powerpc, for further details.
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

Commit e21f8baf ("s390/bug: add entry size to the __bug_table section")
changed the __EMIT_BUG() inline assembly to emit mergeable __bug_table
entries. This is at least currently not needed, but causes problems with
the upcoming s390 ld.lld support:

  ld.lld: error: drivers/nvme/host/fc.o:(__bug_table): writable SHF_MERGE section is not supported

Therefore revert the change for now.
Reported-by: Nathan Chancellor <nathan@kernel.org>
Closes: https://lore.kernel.org/all/20240207-s390-lld-and-orphan-warn-v1-0-8a665b3346ab@kernel.org/Suggested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

ld.bfd defaults to '-z notext' (although it is customizable with the
'--enable-textrel-check' configure option) but ld.lld defaults to '-z
text', which causes issues with building the kernel due to the presence
of dynamic relocations in sections that are not writable.

  ld.lld: error: relocation R_390_64 cannot be used against local symbol; recompile with -fPIC

Add '-z notext' to avoid these errors, as this is expected, which
matches other architectures.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Fangrui Song <maskray@google.com>
Link: https://lore.kernel.org/r/20240207-s390-lld-and-orphan-warn-v1-11-8a665b3346ab@kernel.orgSigned-off-by: Heiko Carstens <hca@linux.ibm.com>

Now that all sections have been properly accounted for in the s390
linker scripts, select CONFIG_ARCH_WANT_LD_ORPHAN_WARN so that
'--orphan-handling' is added to LDFLAGS to catch any future sections
that are added without being described in linker scripts.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Justin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/r/20240207-s390-lld-and-orphan-warn-v1-10-8a665b3346ab@kernel.orgSigned-off-by: Heiko Carstens <hca@linux.ibm.com>

When building with CONFIG_LD_ORPHAN_WARN after selecting
CONFIG_ARCH_HAS_LD_ORPHAN_WARN, there are several series of warnings
from the various discardable sections that the kernel adds for build
purposes that are not needed at runtime:

  s390-linux-ld: warning: orphan section `.export_symbol' from `arch/s390/boot/decompressor.o' being placed in section `.export_symbol'
  s390-linux-ld: warning: orphan section `.discard.addressable' from `arch/s390/boot/decompressor.o' being placed in section `.discard.addressable'
  s390-linux-ld: warning: orphan section `.modinfo' from `arch/s390/boot/decompressor.o' being placed in section `.modinfo'

include/asm-generic/vmlinux.lds.h has a macro for easily discarding
these sections across the kernel named COMMON_DISCARDS, use it to clear
up the warnings.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Justin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/r/20240207-s390-lld-and-orphan-warn-v1-9-8a665b3346ab@kernel.orgSigned-off-by: Heiko Carstens <hca@linux.ibm.com>

When building with CONFIG_LD_ORPHAN_WARN after selecting
CONFIG_ARCH_HAS_LD_ORPHAN_WARN, there is a warning around the '.comment'
section for each file in arch/s390/boot

  s390-linux-ld: warning: orphan section `.comment' from `arch/s390/boot/als.o' being placed in section `.comment'
  s390-linux-ld: warning: orphan section `.comment' from `arch/s390/boot/startup.o' being placed in section `.comment'
  s390-linux-ld: warning: orphan section `.comment' from `arch/s390/boot/physmem_info.o' being placed in section `.comment'

include/asm-generic/vmlinux.lds.h has a macro for required ELF sections
not related to debugging named ELF_DETAILS, use it to clear up the
warnings.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Justin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/r/20240207-s390-lld-and-orphan-warn-v1-8-8a665b3346ab@kernel.orgSigned-off-by: Heiko Carstens <hca@linux.ibm.com>

When building with CONFIG_LD_ORPHAN_WARN after selecting
CONFIG_ARCH_HAS_LD_ORPHAN_WARN, there are several series of warnings for
each file in arch/s390/boot due to the boot linker script not handling
the DWARF debug sections:

  s390-linux-ld: warning: orphan section `.debug_line' from `arch/s390/boot/head.o' being placed in section `.debug_line'
  s390-linux-ld: warning: orphan section `.debug_info' from `arch/s390/boot/head.o' being placed in section `.debug_info'
  s390-linux-ld: warning: orphan section `.debug_abbrev' from `arch/s390/boot/head.o' being placed in section `.debug_abbrev'
  s390-linux-ld: warning: orphan section `.debug_aranges' from `arch/s390/boot/head.o' being placed in section `.debug_aranges'
  s390-linux-ld: warning: orphan section `.debug_str' from `arch/s390/boot/head.o' being placed in section `.debug_str'

include/asm-generic/vmlinux.lds.h has a macro for DWARF debug sections
named DWARF_DEBUG, use it to clear up the warnings.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Fangrui Song <maskray@google.com>
Link: https://lore.kernel.org/r/20240207-s390-lld-and-orphan-warn-v1-7-8a665b3346ab@kernel.orgSigned-off-by: Heiko Carstens <hca@linux.ibm.com>

When building with CONFIG_LD_ORPHAN_WARN after selecting
CONFIG_ARCH_HAS_LD_ORPHAN_WARN, there are several warnings from
arch/s390/boot/head.o due to the unhandled presence of '.rela' sections:

  s390-linux-ld: warning: orphan section `.rela.iplt' from `arch/s390/boot/head.o' being placed in section `.rela.dyn'
  s390-linux-ld: warning: orphan section `.rela.head.text' from `arch/s390/boot/head.o' being placed in section `.rela.dyn'
  s390-linux-ld: warning: orphan section `.rela.got' from `arch/s390/boot/head.o' being placed in section `.rela.dyn'
  s390-linux-ld: warning: orphan section `.rela.data' from `arch/s390/boot/head.o' being placed in section `.rela.dyn'
  s390-linux-ld: warning: orphan section `.rela.data.rel.ro' from `arch/s390/boot/head.o' being placed in section `.rela.dyn'
  s390-linux-ld: warning: orphan section `.rela.iplt' from `arch/s390/boot/head.o' being placed in section `.rela.dyn'
  s390-linux-ld: warning: orphan section `.rela.head.text' from `arch/s390/boot/head.o' being placed in section `.rela.dyn'
  s390-linux-ld: warning: orphan section `.rela.got' from `arch/s390/boot/head.o' being placed in section `.rela.dyn'
  s390-linux-ld: warning: orphan section `.rela.data' from `arch/s390/boot/head.o' being placed in section `.rela.dyn'
  s390-linux-ld: warning: orphan section `.rela.data.rel.ro' from `arch/s390/boot/head.o' being placed in section `.rela.dyn'

These sections are unneeded for the decompressor and they are not
emitted in the binary currently. In a manner similar to other
architectures, coalesce the sections into '.rela.dyn' and ensure it is
zero sized, which is a safe/tested approach versus full discard.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Justin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/r/20240207-s390-lld-and-orphan-warn-v1-6-8a665b3346ab@kernel.orgSigned-off-by: Heiko Carstens <hca@linux.ibm.com>

When building with CONFIG_LD_ORPHAN_WARN after selecting
CONFIG_ARCH_HAS_LD_ORPHAN_WARN, there is a warning about the presence of
an '.init.text' section in arch/s390/boot:

  s390-linux-ld: warning: orphan section `.init.text' from `arch/s390/boot/sclp_early_core.o' being placed in section `.init.text'

arch/s390/boot/sclp_early_core.c includes a file from the main kernel
build, which picks up a usage of '__init' somewhere. For the
decompressed image, this section can just be coalesced into '.text'.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Justin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/r/20240207-s390-lld-and-orphan-warn-v1-5-8a665b3346ab@kernel.orgSigned-off-by: Heiko Carstens <hca@linux.ibm.com>

When building with CONFIG_LD_ORPHAN_WARN after selecting
CONFIG_ARCH_HAS_LD_ORPHAN_WARN, there are some warnings around certain
ELF sections:

  s390-linux-ld: warning: orphan section `.dynstr' from `arch/s390/kernel/head64.o' being placed in section `.dynstr'
  s390-linux-ld: warning: orphan section `.dynamic' from `arch/s390/kernel/head64.o' being placed in section `.dynamic'
  s390-linux-ld: warning: orphan section `.hash' from `arch/s390/kernel/head64.o' being placed in section `.hash'
  s390-linux-ld: warning: orphan section `.gnu.hash' from `arch/s390/kernel/head64.o' being placed in section `.gnu.hash'

Explicitly keep those sections like other architectures when
CONFIG_RELOCATABLE is enabled, which is always true for s390.

[hca@linux.ibm.com: keep sections instead of discarding]
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20240207-s390-lld-and-orphan-warn-v1-4-8a665b3346ab@kernel.orgSigned-off-by: Heiko Carstens <hca@linux.ibm.com>

When building with CONFIG_LD_ORPHAN_WARN after selecting
CONFIG_ARCH_HAS_LD_ORPHAN_WARN, there are a lot of warnings around the
GOT and PLT sections:

  s390-linux-ld: warning: orphan section `.plt' from `arch/s390/kernel/head64.o' being placed in section `.plt'
  s390-linux-ld: warning: orphan section `.got' from `arch/s390/kernel/head64.o' being placed in section `.got'
  s390-linux-ld: warning: orphan section `.got.plt' from `arch/s390/kernel/head64.o' being placed in section `.got.plt'
  s390-linux-ld: warning: orphan section `.iplt' from `arch/s390/kernel/head64.o' being placed in section `.iplt'
  s390-linux-ld: warning: orphan section `.igot.plt' from `arch/s390/kernel/head64.o' being placed in section `.igot.plt'

  s390-linux-ld: warning: orphan section `.iplt' from `arch/s390/boot/head.o' being placed in section `.iplt'
  s390-linux-ld: warning: orphan section `.igot.plt' from `arch/s390/boot/head.o' being placed in section `.igot.plt'
  s390-linux-ld: warning: orphan section `.got' from `arch/s390/boot/head.o' being placed in section `.got'

Currently, only the '.got' section is actually emitted in the final
binary. In a manner similar to other architectures, put the '.got'
section near the '.data' section and coalesce the PLT sections,
checking that the final section is zero sized, which is a safe/tested
approach versus full discard.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Justin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/r/20240207-s390-lld-and-orphan-warn-v1-3-8a665b3346ab@kernel.orgSigned-off-by: Heiko Carstens <hca@linux.ibm.com>

When building with CONFIG_LD_ORPHAN_WARN after selecting
CONFIG_ARCH_HAS_LD_ORPHAN_WARN, there are a lot of warnings around
'.data.rel' sections:

  s390-linux-ld: warning: orphan section `.data.rel' from `kernel/sched/build_utility.o' being placed in section `.data.rel'
  s390-linux-ld: warning: orphan section `.data.rel.local' from `kernel/sched/build_utility.o' being placed in section `.data.rel.local'
  s390-linux-ld: warning: orphan section `.data.rel.ro' from `kernel/sched/build_utility.o' being placed in section `.data.rel.ro'
  s390-linux-ld: warning: orphan section `.data.rel.ro.local' from `kernel/sched/build_utility.o' being placed in section `.data.rel.ro.local'

Describe these in vmlinux.lds.S so there is no more warning and the
sections are placed consistently between linkers.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Justin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/r/20240207-s390-lld-and-orphan-warn-v1-2-8a665b3346ab@kernel.orgSigned-off-by: Heiko Carstens <hca@linux.ibm.com>

arch/s390/boot/vmlinux uses a different linker script and build rules
than the main vmlinux, so the '--orphan-handling' flag is not applied to
it. Add support for '--orphan-handling' so that all sections are
properly described in the linker script, which helps eliminate bugs
between linker implementations having different orphan section
heuristics.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Justin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/r/20240207-s390-lld-and-orphan-warn-v1-1-8a665b3346ab@kernel.orgSigned-off-by: Heiko Carstens <hca@linux.ibm.com>

Move the switch_to() implementation to process.c and use the generic
switch_to.h header file instead, like some other architectures.

This addresses also the oddity that the old switch_to() implementation
assigns the return value of __switch_to() to 'prev' instead of 'last',
like it should.

Remove also all includes of switch_to.h from C files, except process.c.
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

save_access_regs() and restore_access_regs() are only available by
including switch_to.h. This is done by a couple of C files, which have
nothing to do with switch_to(), but only need these functions.

Move both functions to a new header file and improve the implementation:

- Get rid of typedef

- Add memory access instrumentation support

- Use long displacement instructions lamy/stamy instead of lam/stam - all
  current users end up with better code because of this
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

Fix virtual vs physical address confusion. This does not fix a bug
since virtual and physical address spaces are currently the same.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

Code sections in s390 specific kernel code which use floating point or
vector registers all come with a 520 byte stack variable to save already in
use registers, if required.

With INIT_STACK_ALL_PATTERN or INIT_STACK_ALL_ZERO enabled this variable
will always be initialized on function entry in addition to saving register
contents, which contradicts the intention (performance improvement) of such
code sections.

Therefore provide a DECLARE_KERNEL_FPU_ONSTACK() macro which provides
struct kernel_fpu variables with an __uninitialized attribute, and convert
all existing code to use this.

This way only this specific type of stack variable will not be initialized,
regardless of config options.
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20240205154844.3757121-3-hca@linux.ibm.comSigned-off-by: Heiko Carstens <hca@linux.ibm.com>

With INIT_STACK_ALL_PATTERN or INIT_STACK_ALL_ZERO enabled the kernel will
be compiled with -ftrivial-auto-var-init=<...> which causes initialization
of stack variables at function entry time.

In order to avoid the performance impact that comes with this users can use
the "uninitialized" attribute to prevent such initialization.

Therefore provide the __uninitialized macro which can be used for cases
where INIT_STACK_ALL_PATTERN or INIT_STACK_ALL_ZERO is enabled, but only
selected variables should not be initialized.
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20240205154844.3757121-2-hca@linux.ibm.comSigned-off-by: Heiko Carstens <hca@linux.ibm.com>

Now that the driver core can properly handle constant struct bus_type,
move the matrix_bus variable to be a constant structure as well,
placing it into read-only memory which can not be modified at runtime.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: "Ricardo B. Marliere" <ricardo@marliere.net>
Acked-by: Halil Pasic <pasic@linux.ibm.com>
Reviewed-by: Anthony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: "Jason J. Herne" <jjherne@linux.ibm.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20240203-bus_cleanup-s390-v1-6-ac891afc7282@marliere.netSigned-off-by: Heiko Carstens <hca@linux.ibm.com>

Now that the driver core can properly handle constant struct bus_type,
move the ap_bus_type variable to be a constant structure as well,
placing it into read-only memory which can not be modified at runtime.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: "Ricardo B. Marliere" <ricardo@marliere.net>
Reviewed-by: Harald Freudenberger <freude@linux.ibm.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20240203-bus_cleanup-s390-v1-5-ac891afc7282@marliere.netSigned-off-by: Heiko Carstens <hca@linux.ibm.com>

Now that the driver core can properly handle constant struct bus_type,
move the scm_bus_type variable to be a constant structure as well,
placing it into read-only memory which can not be modified at runtime.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: "Ricardo B. Marliere" <ricardo@marliere.net>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20240203-bus_cleanup-s390-v1-4-ac891afc7282@marliere.netSigned-off-by: Heiko Carstens <hca@linux.ibm.com>

Now that the driver core can properly handle constant struct bus_type,
move the ccw_bus_type variable to be a constant structure as well,
placing it into read-only memory which can not be modified at runtime.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: "Ricardo B. Marliere" <ricardo@marliere.net>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20240203-bus_cleanup-s390-v1-3-ac891afc7282@marliere.netSigned-off-by: Heiko Carstens <hca@linux.ibm.com>

Now that the driver core can properly handle constant struct bus_type,
move the css_bus_type variable to be a constant structure as well,
placing it into read-only memory which can not be modified at runtime.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: "Ricardo B. Marliere" <ricardo@marliere.net>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20240203-bus_cleanup-s390-v1-2-ac891afc7282@marliere.netSigned-off-by: Heiko Carstens <hca@linux.ibm.com>

Now that the driver core can properly handle constant struct bus_type,
move the ccwgroup_bus_type variable to be a constant structure as well,
placing it into read-only memory which can not be modified at runtime.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: "Ricardo B. Marliere" <ricardo@marliere.net>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20240203-bus_cleanup-s390-v1-1-ac891afc7282@marliere.netSigned-off-by: Heiko Carstens <hca@linux.ibm.com>

Now that the driver core can properly handle constant struct bus_type,
move the stp_subsys variable to be a constant structure as well,
placing it into read-only memory which can not be modified at runtime.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: "Ricardo B. Marliere" <ricardo@marliere.net>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20240204-bus_cleanup-s390_time-v1-1-d2120156982a@marliere.netSigned-off-by: Heiko Carstens <hca@linux.ibm.com>