Since compat is gone there is only a 64 bit vdso left.
Remove the superfluous "64" suffix everywhere.

Reviewed-by: Jens Remus <jremus@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

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>

As the Makefile is included into other Makefiles it can not be used to
define objects to be built from the current source directory.
However the generic datastore will introduce such a local source file.
Rename the included Makefile so it is clear how it is to be used and to
make room for a regular Makefile in lib/vdso/.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250204-vdso-store-rng-v3-4-13a4669dfc8c@linutronix.de

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 <borntraeger@linux.ibm.com>
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

Provide the s390 specific vdso getrandom() architecture backend.

_vdso_rng_data required data is placed within the _vdso_data vvar page,
by using a hardcoded offset larger than vdso_data.

As required the chacha20 implementation does not write to the stack.

The implementation follows more or less the arm64 implementations and
makes use of vector instructions. It has a fallback to the getrandom()
system call for machines where the vector facility is not installed.

The check if the vector facility is installed, as well as an
optimization for machines with the vector-enhancements facility 2, is
implemented with alternatives, avoiding runtime checks.

Note that __kernel_getrandom() is implemented without the vdso user
wrapper which would setup a stack frame for odd cases (aka very old
glibc variants) where the caller has not done that. All callers of
__kernel_getrandom() are required to setup a stack frame, like the C ABI
requires it.

The vdso testcases vdso_test_getrandom and vdso_test_chacha pass.

Benchmark on a z16:

    $ ./vdso_test_getrandom bench-single
       vdso: 25000000 times in 0.493703559 seconds
    syscall: 25000000 times in 6.584025337 seconds

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Harald Freudenberger <freude@linux.ibm.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

Pull more s390 updates from Alexander Gordeev:

 - Switch read and write software bits for PUDs

 - Add missing hardware bits for PUDs and PMDs

 - Generate unwind information for C modules to fix GDB unwind error for
   vDSO functions

 - Create .build-id links for unstripped vDSO files to enable vDSO
   debugging with symbols

 - Use standard stack frame layout for vDSO generated stack frames to
   manually walk stack frames without DWARF information

 - Rework perf_callchain_user() and arch_stack_walk_user() functions to
   reduce code duplication

 - Skip first stack frame when walking user stack

 - Add basic checks to identify invalid instruction pointers when
   walking stack frames

 - Introduce and use struct stack_frame_vdso_wrapper within vDSO user
   wrapper code to automatically generate an asm-offset define. Also use
   STACK_FRAME_USER_OVERHEAD instead of STACK_FRAME_OVERHEAD to document
   that the code works with user space stack

 - Clear the backchain of the extra stack frame added by the vDSO user
   wrapper code. This allows the user stack walker to detect and skip
   the non-standard stack frame. Without this an incorrect instruction
   pointer would be added to stack traces.

 - Rewrite psw_idle() function in C to ease maintenance and further
   enhancements

 - Remove get_vtimer() function and use get_cpu_timer() instead

 - Mark psw variable in __load_psw_mask() as __unitialized to avoid
   superfluous clearing of PSW

 - Remove obsolete and superfluous comment about removed TIF_FPU flag

 - Replace memzero_explicit() and kfree() with kfree_sensitive() to fix
   warnings reported by Coccinelle

 - Wipe sensitive data and all copies of protected- or secure-keys from
   stack when an IOCTL fails

 - Both do_airq_interrupt() and do_io_interrupt() functions set
   CIF_NOHZ_DELAY flag. Move it in do_io_irq() to simplify the code

 - Provide iucv_alloc_device() and iucv_release_device() helpers, which
   can be used to deduplicate more or less identical IUCV device
   allocation and release code in four different drivers

 - Make use of iucv_alloc_device() and iucv_release_device() helpers to
   get rid of quite some code and also remove a cast to an incompatible
   function (clang W=1)

 - There is no user of iucv_root outside of the core IUCV code left.
   Therefore remove the EXPORT_SYMBOL

 - __apply_alternatives() contains a runtime check which verifies that
   the size of the to be patched code area is even. Convert this to a
   compile time check

 - Increase size of buffers for sending z/VM CP DIAGNOSE X'008' commands
   from 128 to 240

 - Do not accept z/VM CP DIAGNOSE X'008' commands longer than maximally
   allowed

 - Use correct defines IPL_BP_NVME_LEN and IPL_BP0_NVME_LEN instead of
   IPL_BP_FCP_LEN and IPL_BP0_FCP_LEN ones to initialize NVMe reIPL
   block on 'scp_data' sysfs attribute update

 - Initialize the correct fields of the NVMe dump block, which were
   confused with FCP fields

 - Refactor macros for 'scp_data' (re-)IPL sysfs attribute to reduce
   code duplication

 - Introduce 'scp_data' sysfs attribute for dump IPL to allow tools such
   as dumpconf passing additional kernel command line parameters to a
   stand-alone dumper

 - Rework the CPACF query functions to use the correct RRE or RRF
   instruction formats and set instruction register fields correctly

 - Instead of calling BUG() at runtime force a link error during compile
   when a unsupported opcode is used with __cpacf_query() or
   __cpacf_check_opcode() functions

 - Fix a crash in ap_parse_bitmap_str() function on /sys/bus/ap/apmask
   or /sys/bus/ap/aqmask sysfs file update with a relative mask value

 - Fix "bindings complete" udev event which should be sent once all AP
   devices have been bound to device drivers and again when unbind/bind
   actions take place and all AP devices are bound again

 - Facility list alt_stfle_fac_list is nowhere used in the decompressor,
   therefore remove it there

 - Remove custom kprobes insn slot allocator in favour of the standard
   module_alloc() one, since kernel image and module areas are located
   within 4GB

 - Use kvcalloc() instead of kvmalloc_array() in zcrypt driver to avoid
   calling memset() with a large byte count and get rid of the sparse
   warning as result

* tag 's390-6.10-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (39 commits)
  s390/zcrypt: Use kvcalloc() instead of kvmalloc_array()
  s390/kprobes: Remove custom insn slot allocator
  s390/boot: Remove alt_stfle_fac_list from decompressor
  s390/ap: Fix bind complete udev event sent after each AP bus scan
  s390/ap: Fix crash in AP internal function modify_bitmap()
  s390/cpacf: Make use of invalid opcode produce a link error
  s390/cpacf: Split and rework cpacf query functions
  s390/ipl: Introduce sysfs attribute 'scp_data' for dump ipl
  s390/ipl: Introduce macros for (re)ipl sysfs attribute 'scp_data'
  s390/ipl: Fix incorrect initialization of nvme dump block
  s390/ipl: Fix incorrect initialization of len fields in nvme reipl block
  s390/ipl: Do not accept z/VM CP diag X'008' cmds longer than max length
  s390/ipl: Fix size of vmcmd buffers for sending z/VM CP diag X'008' cmds
  s390/alternatives: Convert runtime sanity check into compile time check
  s390/iucv: Unexport iucv_root
  tty: hvc-iucv: Make use of iucv_alloc_device()
  s390/smsgiucv_app: Make use of iucv_alloc_device()
  s390/netiucv: Make use of iucv_alloc_device()
  s390/vmlogrdr: Make use of iucv_alloc_device()
  s390/iucv: Provide iucv_alloc_device() / iucv_release_device()
  ...

Now Kbuild provides reasonable defaults for objtool, sanitizers, and
profilers.

Remove redundant variables.

Note:

This commit changes the coverage for some objects:

  - include arch/mips/vdso/vdso-image.o into UBSAN, GCOV, KCOV
  - include arch/sparc/vdso/vdso-image-*.o into UBSAN
  - include arch/sparc/vdso/vma.o into UBSAN
  - include arch/x86/entry/vdso/extable.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
  - include arch/x86/entry/vdso/vdso-image-*.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
  - include arch/x86/entry/vdso/vdso32-setup.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
  - include arch/x86/entry/vdso/vma.o into GCOV, KCOV
  - include arch/x86/um/vdso/vma.o into KASAN, GCOV, KCOV

I believe these are positive effects because all of them are kernel
space objects.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Roberto Sassu <roberto.sassu@huawei.com>

By default user space is compiled with standard stack frame layout and not
with the packed stack layout. The vdso code however inherited the
-mpacked-stack compiler option from the kernel. Remove this option to make
sure the vdso is compiled with standard stack frame layout.

This makes sure that the stack frame backchain location for vdso generated
stack frames is the same like for calling code (if compiled with default
options). This allows to manually walk stack frames without DWARF
information, like the kernel is doing it e.g. with arch_stack_walk_user().

Fixes: 4bff8cb54502 ("s390: convert to GENERIC_VDSO")
Reviewed-by: Jens Remus <jremus@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

GDB fails to unwind vDSO functions with error message "PC not saved",
for instance when stepping through gettimeofday().

Add -fasynchronous-unwind-tables to CFLAGS to generate .eh_frame
DWARF unwind information for the vDSO C modules.

Fixes: 4bff8cb54502 ("s390: convert to GENERIC_VDSO")
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

Kbuild conventionally uses $(obj)/ for generated files, and $(src)/ for
checked-in source files. It is merely a convention without any functional
difference. In fact, $(obj) and $(src) are exactly the same, as defined
in scripts/Makefile.build:

    src := $(obj)

When the kernel is built in a separate output directory, $(src) does
not accurately reflect the source directory location. While Kbuild
resolves this discrepancy by specifying VPATH=$(srctree) to search for
source files, it does not cover all cases. For example, when adding a
header search path for local headers, -I$(srctree)/$(src) is typically
passed to the compiler.

This introduces inconsistency between upstream and downstream Makefiles
because $(src) is used instead of $(srctree)/$(src) for the latter.

To address this inconsistency, this commit changes the semantics of
$(src) so that it always points to the directory in the source tree.

Going forward, the variables used in Makefiles will have the following
meanings:

  $(obj)     - directory in the object tree
  $(src)     - directory in the source tree  (changed by this commit)
  $(objtree) - the top of the kernel object tree
  $(srctree) - the top of the kernel source tree

Consequently, $(srctree)/$(src) in upstream Makefiles need to be replaced
with $(src).

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>