s390/lowcore: Remove unused machine_flags

The machine_flags member in struct lowcore is not used anymore.
Remove it.

Reviewed-by: Sven Schnelle <[email protected]>
Signed-off-by: Heiko Carstens <

s390/lowcore: Remove unused machine_flags

The machine_flags member in struct lowcore is not used anymore.
Remove it.

Reviewed-by: Sven Schnelle <[email protected]>
Signed-off-by: Heiko Carstens <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>

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s390/bear: Convert cpu_has_bear() to cpu feature function

Get rid of the cpu_has_bear jump label and convert cpu_has_bear() to a cpu
feature function using test_facility() and with that use a static

s390/bear: Convert cpu_has_bear() to cpu feature function

Get rid of the cpu_has_bear jump label and convert cpu_has_bear() to a cpu
feature function using test_facility() and with that use a static branch.

Reviewed-by: Vasily Gorbik <[email protected]>
Signed-off-by: Heiko Carstens <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>

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s390: Convert MACHINE_IS_[LPAR|VM|KVM], etc, machine_is_[lpar|vm|kvm]()

Move machine type detection to the decompressor and use static branches
to implement and use machine_is_[lpar|vm|kvm]() instea

s390: Convert MACHINE_IS_[LPAR|VM|KVM], etc, machine_is_[lpar|vm|kvm]()

Move machine type detection to the decompressor and use static branches
to implement and use machine_is_[lpar|vm|kvm]() instead of a runtime check
via MACHINE_IS_[LPAR|VM|KVM].

Reviewed-by: Vasily Gorbik <[email protected]>
Signed-off-by: Heiko Carstens <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>

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s390/lowcore: Convert relocated lowcore alternative to machine feature

Convert the explicit relocated lowcore alternative type to a more
generic machine feature. This only reduces the number of alte

s390/lowcore: Convert relocated lowcore alternative to machine feature

Convert the explicit relocated lowcore alternative type to a more
generic machine feature. This only reduces the number of alternative
types, but has no impact on code generation.

Reviewed-by: Vasily Gorbik <[email protected]>
Signed-off-by: Heiko Carstens <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>

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s390/cpufeature: Convert MACHINE_HAS_EDAT2 to cpu_has_edat2()

Convert MACHINE_HAS_... to cpu_has_...() which uses test_facility() instead
of testing the machine_flags lowcore member if the feature i

s390/cpufeature: Convert MACHINE_HAS_EDAT2 to cpu_has_edat2()

Convert MACHINE_HAS_... to cpu_has_...() which uses test_facility() instead
of testing the machine_flags lowcore member if the feature is present.

test_facility() generates better code since it results in a static branch
without accessing memory. The branch is patched via alternatives by the
decompressor depending on the availability of the required facility.

Reviewed-by: Vasily Gorbik <[email protected]>
Signed-off-by: Heiko Carstens <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>

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s390/sclp: Initialize sclp subsystem via arch_cpu_finalize_init()

With the switch to GENERIC_CPU_DEVICES an early call to the sclp subsystem
was added to smp_prepare_cpus(). This will usually succee

s390/sclp: Initialize sclp subsystem via arch_cpu_finalize_init()

With the switch to GENERIC_CPU_DEVICES an early call to the sclp subsystem
was added to smp_prepare_cpus(). This will usually succeed since the sclp
subsystem is implicitly initialized early enough if an sclp based console
is present.

If no such console is present the initialization happens with an
arch_initcall(); in such cases calls to the sclp subsystem will fail.
For CPU detection this means that the fallback sigp loop will be used
permanently to detect CPUs instead of the preferred READ_CPU_INFO sclp
request.

Fix this by adding an explicit early sclp_init() call via
arch_cpu_finalize_init().

Reported-by: Sheshu Ramanandan <[email protected]>
Fixes: 4a39f12e753d ("s390/smp: Switch to GENERIC_CPU_DEVICES")
Reviewed-by: Peter Oberparleiter <[email protected]>
Signed-off-by: Heiko Carstens <[email protected]>
Signed-off-by: Alexander Gordeev <[email protected]>

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s390: Optimize __pa/__va when RANDOMIZE_IDENTITY_BASE is off

Use a zero identity base when CONFIG_RANDOMIZE_IDENTITY_BASE is off,
slightly optimizing __pa/__va calculations.

Signed-off-by: Vasily G

s390: Optimize __pa/__va when RANDOMIZE_IDENTITY_BASE is off

Use a zero identity base when CONFIG_RANDOMIZE_IDENTITY_BASE is off,
slightly optimizing __pa/__va calculations.

Signed-off-by: Vasily Gorbik <[email protected]>
Acked-by: Alexander Gordeev <[email protected]>
Signed-off-by: Alexander Gordeev <[email protected]>

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s390/boot: Add physmem tracking debug support

Introduce boot_debug() calls to track memory detection, online ranges,
reserved areas, and allocations (except for VMEM allocations, which are
too frequ

s390/boot: Add physmem tracking debug support

Introduce boot_debug() calls to track memory detection, online ranges,
reserved areas, and allocations (except for VMEM allocations, which are
too frequent). Instead introduce dump_physmem_reserved() function which
prints out full memory tracking information. This helps in debugging
early boot memory handling.

Signed-off-by: Vasily Gorbik <[email protected]>
Acked-by: Heiko Carstens <[email protected]>
Signed-off-by: Alexander Gordeev <[email protected]>

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s390/boot: Add timestamps to early boot messages

When CONFIG_PRINTK_TIME is enabled, add timestamps to boot messages in
the same format as regular printk. Timestamps appear only with earlyprintk
and

s390/boot: Add timestamps to early boot messages

When CONFIG_PRINTK_TIME is enabled, add timestamps to boot messages in
the same format as regular printk. Timestamps appear only with earlyprintk
and are stored in the boot messages ring buffer, but are not propagated
to main kernel messages (if earlyprintk is not enabled). This prevents
double timestamps in the output.

Signed-off-by: Vasily Gorbik <[email protected]>
Acked-by: Heiko Carstens <[email protected]>
Signed-off-by: Alexander Gordeev <[email protected]>

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s390/boot: Add prefix filtering to bootdebug messages

Enhance boot debugging by allowing the "bootdebug" kernel parameter to
accept an optional comma-separated list of prefixes. Only debug messages

s390/boot: Add prefix filtering to bootdebug messages

Enhance boot debugging by allowing the "bootdebug" kernel parameter to
accept an optional comma-separated list of prefixes. Only debug messages
starting with these prefixes will be printed during boot. For example:

bootdebug=startup,vmem

Not specifying a filter for the "bootdebug" parameter prints all debug
messages. The `boot_fmt` macro can be defined to set a common prefix:

#define boot_fmt(fmt) "startup: " fmt

Signed-off-by: Vasily Gorbik <[email protected]>
Acked-by: Heiko Carstens <[email protected]>
Signed-off-by: Alexander Gordeev <[email protected]>

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s390/boot: Add bootdebug option to control debug messages

Suppress decompressor debug messages by default, similar to regular
kernel debug messages that require 'DEBUG' or 'dyndbg' to be enabled
(de

s390/boot: Add bootdebug option to control debug messages

Suppress decompressor debug messages by default, similar to regular
kernel debug messages that require 'DEBUG' or 'dyndbg' to be enabled
(depending on CONFIG_DYNAMIC_DEBUG). Introduce a 'bootdebug' option to
enable printing these messages when needed.

All messages are still stored in the boot ring buffer regardless.

To enable boot debug messages:

bootdebug debug

Or combine with 'earlyprintk' to print them without delay:

bootdebug debug earlyprintk

Signed-off-by: Vasily Gorbik <[email protected]>
Acked-by: Heiko Carstens <[email protected]>
Signed-off-by: Alexander Gordeev <[email protected]>

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s390/boot: Defer boot messages when earlyprintk is not enabled

When earlyprintk is not specified, boot messages are only stored in a
ring buffer to be printed later by printk when console driver is

s390/boot: Defer boot messages when earlyprintk is not enabled

When earlyprintk is not specified, boot messages are only stored in a
ring buffer to be printed later by printk when console driver is
registered.

Critical messages from boot_emerg() are always printed immediately,
even without earlyprintk.

Signed-off-by: Vasily Gorbik <[email protected]>
Acked-by: Heiko Carstens <[email protected]>
Signed-off-by: Alexander Gordeev <[email protected]>

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mm/memblock: add memblock_alloc_or_panic interface

Before SLUB initialization, various subsystems used memblock_alloc to
allocate memory. In most cases, when memory allocation fails, an
immediate p

mm/memblock: add memblock_alloc_or_panic interface

Before SLUB initialization, various subsystems used memblock_alloc to
allocate memory. In most cases, when memory allocation fails, an
immediate panic is required. To simplify this behavior and reduce
repetitive checks, introduce `memblock_alloc_or_panic`. This function
ensures that memory allocation failures result in a panic automatically,
improving code readability and consistency across subsystems that require
this behavior.

[[email protected]: arch/s390: save_area_alloc default failure behavior changed to panic]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lore.kernel.org/lkml/[email protected]/
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Guo Weikang <[email protected]>
Acked-by: Geert Uytterhoeven <[email protected]> [m68k]
Reviewed-by: Alexander Gordeev <[email protected]> [s390]
Acked-by: Mike Rapoport (Microsoft) <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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s390/mm: Simplify noexec page protection handling

By default page protection definitions like PAGE_RX have the _PAGE_NOEXEC
bit set. For older machines without the instruction execution protection
f

s390/mm: Simplify noexec page protection handling

By default page protection definitions like PAGE_RX have the _PAGE_NOEXEC
bit set. For older machines without the instruction execution protection
facility this bit is not allowed to be used in page table entries, and
therefore must be removed.

This is done at a couple of page table walkers, but also at some but not
all page table modification functions like ptep_modify_prot_commit(). Avoid
all of this and change the page, segment and region3 protection definitions
so that the noexec bit is masked out automatically if the instruction
execution-protection facility is not available. This is similar to what
also various other architectures do which had to solve the same problem.

Reviewed-by: Gerald Schaefer <[email protected]>
Acked-by: Alexander Gordeev <[email protected]>
Signed-off-by: Heiko Carstens <[email protected]>
Signed-off-by: Alexander Gordeev <[email protected]>

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s390: Remove __bootdata annotations from declarations

For consistency, remove the `__bootdata` and `__bootdata_preserved`
section annotations from variable declarations in header files. Section
anno

s390: Remove __bootdata annotations from declarations

For consistency, remove the `__bootdata` and `__bootdata_preserved`
section annotations from variable declarations in header files. Section
annotations should be applied to definitions, not declarations. This
change moves the annotations to the variable definitions in the
corresponding source files.

Acked-by: Heiko Carstens <[email protected]>
Acked-by: Alexander Gordeev <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>
Signed-off-by: Alexander Gordeev <[email protected]>

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s390/setup: Cleanup stack_alloc() and stack_free()

Some small cleanups to stack_alloc() and stack_free():

- Rename ret to stack to reflect what the variable is used for
- Whitespace removal

Review

s390/setup: Cleanup stack_alloc() and stack_free()

Some small cleanups to stack_alloc() and stack_free():

- Rename ret to stack to reflect what the variable is used for
- Whitespace removal

Reviewed-by: Vasily Gorbik <[email protected]>
Signed-off-by: Heiko Carstens <[email protected]>
Signed-off-by: Alexander Gordeev <[email protected]>

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s390/Kconfig: Select VMAP_STACK unconditionally

There is no point in supporting !VMAP_STACK kernel builds. VMAP_STACK has
proven to work since many years. Also, since KASAN_VMALLOC is supported,
ker

s390/Kconfig: Select VMAP_STACK unconditionally

There is no point in supporting !VMAP_STACK kernel builds. VMAP_STACK has
proven to work since many years. Also, since KASAN_VMALLOC is supported,
kernels built with !VMAP_STACK are completely untested.

Therefore select VMAP_STACK unconditionally and remove all config options
and code required for !VMAP_STACK builds.

Acked-by: Christian Borntraeger <[email protected]>
Reviewed-by: Vasily Gorbik <[email protected]>
Signed-off-by: Heiko Carstens <[email protected]>
Signed-off-by: Alexander Gordeev <[email protected]>

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s390/mm: Prevent lowcore vs identity mapping overlap

The identity mapping position in virtual memory is randomized
together with the kernel mapping. That position can never
overlap with the lowcore

s390/mm: Prevent lowcore vs identity mapping overlap

The identity mapping position in virtual memory is randomized
together with the kernel mapping. That position can never
overlap with the lowcore even when the lowcore is relocated.

Prevent overlapping with the lowcore to allow independent
positioning of the identity mapping. With the current value
of the alternative lowcore address of 0x70000 the overlap
could happen in case the identity mapping is placed at zero.

This is a prerequisite for uncoupling of randomization base
of kernel image and identity mapping in virtual memory.

Acked-by: Vasily Gorbik <[email protected]>
Signed-off-by: Alexander Gordeev <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>

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s390: Add infrastructure to patch lowcore accesses

The s390 architecture defines two special per-CPU data pages
called the "prefix area". In s390-linux terminology this is usually
called "lowcore".

s390: Add infrastructure to patch lowcore accesses

The s390 architecture defines two special per-CPU data pages
called the "prefix area". In s390-linux terminology this is usually
called "lowcore". This memory area contains system configuration
data like old/new PSW's for system call/interrupt/machine check
handlers and lots of other data. It is normally mapped to logical
address 0. This area can only be accessed when in supervisor mode.

This means that kernel code can dereference NULL pointers, because
accesses to address 0 are allowed. Parts of lowcore can be write
protected, but read accesses and write accesses outside of the write
protected areas are not caught.

To remove this limitation for debugging and testing, remap lowcore to
another address and define a function get_lowcore() which simply
returns the address where lowcore is mapped at. This would normally
introduce a pointer dereference (=memory read). As lowcore is used
for several very often used variables, add code to patch this function
during runtime, so we avoid the memory reads.

For C code get_lowcore() has to be used, for assembly code it is
the GET_LC macro. When using this macro/function a reference is added
to alternative patching. All these locations will be patched to the
actual lowcore location when the kernel is booted or a module is loaded.

To make debugging/bisecting problems easier, this patch adds all the
infrastructure but the lowcore address is still hardwired to 0. This
way the code can be converted on a per function basis, and the
functionality is enabled in a patch after all the functions have
been converted.

Note that this requires at least z16 because the old lpsw instruction
only allowed a 12 bit displacement. z16 introduced lpswey which allows
20 bits (signed), so the lowcore can effectively be mapped from
address 0 - 0x7e000. To use 0x7e000 as address, a 6 byte lgfi
instruction would have to be used in the alternative. To save two
bytes, llilh can be used, but this only allows to set bits 16-31 of
the address. In order to use the llilh instruction, use 0x70000 as
alternative lowcore address. This is still large enough to catch
NULL pointer dereferences into large arrays.

Reviewed-by: Heiko Carstens <[email protected]>
Signed-off-by: Sven Schnelle <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>

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s390/alternatives: Remove alternative facility list

The alternative and the normal facility list are always identical. Remove
the alternative facility list, which allows to simplify the alternatives

s390/alternatives: Remove alternative facility list

The alternative and the normal facility list are always identical. Remove
the alternative facility list, which allows to simplify the alternatives
code.

Acked-by: Alexander Gordeev <[email protected]>
Tested-by: Sven Schnelle <[email protected]>
Signed-off-by: Heiko Carstens <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>

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s390: Move CIF flags to struct pcpu

To allow testing flags for offline CPUs, move the CIF flags
to struct pcpu. To avoid having to calculate the array index
for each access, add a pointer to the pcp

s390: Move CIF flags to struct pcpu

To allow testing flags for offline CPUs, move the CIF flags
to struct pcpu. To avoid having to calculate the array index
for each access, add a pointer to the pcpu member for the current
cpu to lowcore.

Reviewed-by: Heiko Carstens <[email protected]>
Signed-off-by: Sven Schnelle <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>

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s390/setup: Fix __pa/__va for modules under non-GPL licenses

The struct vm_layout contains fields used in __pa/__va calculations. Such
fundamental things have to be exported with EXPORT_SYMBOL to av

s390/setup: Fix __pa/__va for modules under non-GPL licenses

The struct vm_layout contains fields used in __pa/__va calculations. Such
fundamental things have to be exported with EXPORT_SYMBOL to avoid
breakages of out-of-tree modules under non-GPL licenses.

Fixes: 7de0446f0b26 ("s390/boot: Make identity mapping base address explicit")
Acked-by: Heiko Carstens <[email protected]>
Acked-by: Alexander Gordeev <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>

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s390: Replace S390_lowcore by get_lowcore()

Replace all S390_lowcore usages in arch/s390/ by get_lowcore().

Acked-by: Heiko Carstens <[email protected]>
Signed-off-by: Sven Schnelle <[email protected]

s390: Replace S390_lowcore by get_lowcore()

Replace all S390_lowcore usages in arch/s390/ by get_lowcore().

Acked-by: Heiko Carstens <[email protected]>
Signed-off-by: Sven Schnelle <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>

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s390/boot: Remove alt_stfle_fac_list from decompressor

It is nowhere used in the decompressor, therefore remove it.

Fixes: 17e89e1340a3 ("s390/facilities: move stfl information from lowcore to glob

s390/boot: Remove alt_stfle_fac_list from decompressor

It is nowhere used in the decompressor, therefore remove it.

Fixes: 17e89e1340a3 ("s390/facilities: move stfl information from lowcore to global data")
Reviewed-by: Heiko Carstens <[email protected]>
Signed-off-by: Sven Schnelle <[email protected]>
Signed-off-by: Heiko Carstens <[email protected]>

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s390/boot: Make .amode31 section address range explicit

This is a preparatory rework to allow uncoupling virtual
and physical addresses spaces.

Introduce .amode31 section address range AMODE31_STAR

s390/boot: Make .amode31 section address range explicit

This is a preparatory rework to allow uncoupling virtual
and physical addresses spaces.

Introduce .amode31 section address range AMODE31_START
and AMODE31_END macros for later use.

Acked-by: Heiko Carstens <[email protected]>
Signed-off-by: Alexander Gordeev <[email protected]>

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