linux-toradex.git/arch/s390/kernel/Makefile, branch v6.16

arch: use always-$(KBUILD_BUILTIN) for vmlinux.lds

2025-06-07T05:38:07+00:00

The extra-y syntax is deprecated. Instead, use always-$(KBUILD_BUILTIN),
which behaves equivalently.

Signed-off-by: Masahiro Yamada 
Acked-by: Johannes Berg 
Reviewed-by: Nicolas Schier

s390/diag: Move diag.c to diag specific folder

2024-12-17T11:46:14+00:00

Move implementation of s390 diagnose code to diag specific folder.

Reviewed-by: Heiko Carstens 
Signed-off-by: Sumanth Korikkar 
Signed-off-by: Alexander Gordeev

s390/diag324: Retrieve power readings via diag 0x324

2024-12-17T11:46:14+00:00

Retrieve electrical power readings for resources in a computing
environment via diag 0x324. diag 0x324 stores the power readings in the
power information block (pib).

Provide power readings from pib via diag324 ioctl interface.  diag324
ioctl provides new pib to the user only if the threshold time has passed
since the last call. Otherwise, cache data is returned. When there are
no active readers, cleanup of pib buffer is performed.

Reviewed-by: Heiko Carstens 
Signed-off-by: Sumanth Korikkar 
Signed-off-by: Alexander Gordeev

s390/crypto: Display Query and Query Authentication Information in sysfs

2024-09-12T12:13:27+00:00

Displays the query (fc=0) and query authentication information (fc=127)
as binary in sysfs per CPACF instruction. Files are located in
/sys/devices/system/cpu/cpacf/. These information can be fetched via
asm already except for PCKMO because this instruction is privileged. To
offer a unified interface all CPACF instructions will have this
information displayed in sysfs in files _query_raw and
_query_auth_info_raw.

A new tool introduced into s390-tools called cpacfinfo will use this
information to convert and display in human readable form.

Suggested-by: Harald Freudenberger 
Reviewed-by: Harald Freudenberger 
Acked-by: Heiko Carstens 
Signed-off-by: Finn Callies 
Signed-off-by: Vasily Gorbik

s390/hiperdispatch: Introduce hiperdispatch

2024-08-29T20:56:35+00:00

When LPAR is in vertical polarization, CPUs get different polarization
values, namely vertical high, vertical medium and vertical low. These
values represent the likelyhood of the CPU getting physical runtime.
Vertical high CPUs will always get runtime and others get varying
runtime depending on the load the CEC is under.

Vertical high and vertical medium CPUs are considered the CPUs which the
current LPAR has the entitlement to run on. The vertical lows are on the
other hand are borrowed CPUs which would only be given to the LPAR by
hipervisor when the other LPARs are not utilizing them.

Using the CPU capacities, hint linux scheduler when it should prioritise
vertical high and vertical medium CPUs over vertical low CPUs.
By tracking various system statistics hiperdispatch determines when to
adjust cpu capacities.
After each adjustment, rebuilding of scheduler domains is necessary to
notify the scheduler about capacity changes but since this operation is
costly it should be done as sparsely as possible.

Acked-by: Vasily Gorbik 
Co-developed-by: Tobias Huschle 
Signed-off-by: Tobias Huschle 
Signed-off-by: Mete Durlu 
Signed-off-by: Vasily Gorbik

s390/wti: Prepare graceful CPU pre-emption on wti reception

2024-08-29T20:56:34+00:00

When a warning track interrupt is received, the kernel has only a very
limited amount of time to make sure, that the CPU can be yielded as
gracefully as possible before being pre-empted by the hypervisor.

The interrupt handler for the wti therefore unparks a kernel thread
which has being created on boot re-using the CPU hotplug kernel thread
infrastructure. These threads exist per CPU and are assigned the
highest possible real-time priority. This makes sure, that said threads
will execute as soon as possible as the scheduler should pre-empt any
other running user tasks to run the real-time thread.

Furthermore, the interrupt handler disables all I/O interrupts to
prevent additional interrupt processing on the soon-preempted CPU.
Interrupt handlers are likely to take kernel locks, which in the worst
case, will be kept while the interrupt handler is pre-empted from itself
underlying physical CPU. In that case, all tasks or interrupt handlers
on other CPUs would have to wait for the pre-empted CPU being dispatched
again. By preventing further interrupt processing, this risk is
minimized.

Once the CPU gets dispatched again, the real-time kernel thread regains
control, reenables interrupts and parks itself again.

Acked-by: Heiko Carstens 
Reviewed-by: Mete Durlu 
Signed-off-by: Tobias Huschle 
Signed-off-by: Vasily Gorbik

s390/entry: Move early program check handler to entry.S

2024-08-07T18:52:53+00:00

Have all program check handlers in one file to make future changes easy.

Reviewed-by: Alexander Gordeev 
Reviewed-by: Sven Schnelle 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390: Remove protvirt and kvm config guards for uv code

2024-07-23T14:02:33+00:00

Removing the CONFIG_PROTECTED_VIRTUALIZATION_GUEST ifdefs and config
option as well as CONFIG_KVM ifdefs in uv files.

Having this configurable has been more of a pain than a help.
It's time to remove the ifdefs and the config option.

Signed-off-by: Janosch Frank 
Acked-by: Christian Borntraeger 
Acked-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390/kprobes: Remove custom insn slot allocator

2024-05-16T08:31:32+00:00

Since commit c98d2ecae08f ("s390/mm: Uncouple physical vs virtual address
spaces") the kernel image and module area are within the same 4GB area.

This eliminates the need of a custom insn slot allocator for kprobes within
the kernel image, since standard module_alloc() allocated pages are
sufficient for PC relative instructions with a signed 32 bit offset.

Signed-off-by: Heiko Carstens

s390/ftrace: Use unwinder instead of __builtin_return_address()

2024-04-29T15:33:30+00:00

Using __builtin_return_address(n) might return undefined values
when used with values of n outside of the stack. This was noticed
when __builtin_return_address() was called in ftrace on top level
functions like the interrupt handlers.

As this behaviour cannot be fixed, use the s390 stack unwinder and
remove the ftrace compilation flags for unwind_bc.c and stacktrace.c
to prevent the unwinding function polluting function traces.

Another advantage is that this also works with clang.

Reviewed-by: Heiko Carstens 
Signed-off-by: Sven Schnelle 
Signed-off-by: Alexander Gordeev