Merge tag 's390-6.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 updates from Heiko Carstens:

- Provide a new interface for dynamic configuration and deconfiguration

Merge tag 's390-6.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 updates from Heiko Carstens:

- Provide a new interface for dynamic configuration and deconfiguration
of hotplug memory, allowing with and without memmap_on_memory
support. This makes the way memory hotplug is handled on s390 much
more similar to other architectures

- Remove compat support. There shouldn't be any compat user space
around anymore, therefore get rid of a lot of code which also doesn't
need to be tested anymore

- Add stackprotector support. GCC 16 will get new compiler options,
which allow to generate code required for kernel stackprotector
support

- Merge pai_crypto and pai_ext PMU drivers into a new driver. This
removes a lot of duplicated code. The new driver is also extendable
and allows to support new PMUs

- Add driver override support for AP queues

- Rework and extend zcrypt and AP trace events to allow for tracing of
crypto requests

- Support block sizes larger than 65535 bytes for CCW tape devices

- Since the rework of the virtual kernel address space the module area
and the kernel image are within the same 4GB area. This eliminates
the need of weak per cpu variables. Get rid of
ARCH_MODULE_NEEDS_WEAK_PER_CPU

- Various other small improvements and fixes

* tag 's390-6.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (92 commits)
watchdog: diag288_wdt: Remove KMSG_COMPONENT macro
s390/entry: Use lay instead of aghik
s390/vdso: Get rid of -m64 flag handling
s390/vdso: Rename vdso64 to vdso
s390: Rename head64.S to head.S
s390/vdso: Use common STABS_DEBUG and DWARF_DEBUG macros
s390: Add stackprotector support
s390/modules: Simplify module_finalize() slightly
s390: Remove KMSG_COMPONENT macro
s390/percpu: Get rid of ARCH_MODULE_NEEDS_WEAK_PER_CPU
s390/ap: Restrict driver_override versus apmask and aqmask use
s390/ap: Rename mutex ap_perms_mutex to ap_attr_mutex
s390/ap: Support driver_override for AP queue devices
s390/ap: Use all-bits-one apmask/aqmask for vfio in_use() checks
s390/debug: Update description of resize operation
s390/syscalls: Switch to generic system call table generation
s390/syscalls: Remove system call table pointer from thread_struct
s390/uapi: Remove 31 bit support from uapi header files
s390: Remove compat support
tools: Remove s390 compat support
...

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s390: Add stackprotector support

Stackprotector support was previously unavailable on s390 because by
default compilers generate code which is not suitable for the kernel:
the canary value is access

s390: Add stackprotector support

Stackprotector support was previously unavailable on s390 because by
default compilers generate code which is not suitable for the kernel:
the canary value is accessed via thread local storage, where the address
of thread local storage is within access registers 0 and 1.

Using those registers also for the kernel would come with a significant
performance impact and more complicated kernel entry/exit code, since
access registers contents would have to be exchanged on every kernel entry
and exit.

With the upcoming gcc 16 release new compiler options will become available
which allow to generate code suitable for the kernel. [1]

Compiler option -mstack-protector-guard=global instructs gcc to generate
stackprotector code that refers to a global stackprotector canary value via
symbol __stack_chk_guard. Access to this value is guaranteed to occur via
larl and lgrl instructions.

Furthermore, compiler option -mstack-protector-guard-record generates a
section containing all code addresses that reference the canary value.

To allow for per task canary values the instructions which load the address
of __stack_chk_guard are patched so they access a lowcore field instead: a
per task canary value is available within the task_struct of each task, and
is written to the per-cpu lowcore location on each context switch.

Also add sanity checks and debugging option to be consistent with other
kernel code patching mechanisms.

Full debugging output can be enabled with the following kernel command line
options:

debug_stackprotector
bootdebug
ignore_loglevel
earlyprintk
dyndbg="file stackprotector.c +p"

Example debug output:

stackprot: 0000021e402d4eda: c010005a9ae3 -> c01f00070240

where "<insn address>: <old insn> -> <new insn>".

[1] gcc commit 0cd1f03939d5 ("s390: Support global stack protector")

Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

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