linux.git/arch/s390/include/asm/vdso, branch master

s390/time: Remove in-kernel time steering

2025-07-21T10:41:55+00:00

Remove the in-kernel time steering in favour of the new
ptp s390 driver, which allows the kernel clock to be steered
more precise.

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

s390: Replace ASSEMBLY with ASSEMBLER in non-uapi headers

2025-06-16T14:23:02+00:00

While the GCC and Clang compilers already define __ASSEMBLER__
automatically when compiling assembler code, __ASSEMBLY__ is a
macro that only gets defined by the Makefiles in the kernel.
This is bad since macros starting with two underscores are names
that are reserved by the C language. It can also be very confusing
for the developers when switching between userspace and kernelspace
coding, or when dealing with uapi headers that rather should use
__ASSEMBLER__  instead. So let's now standardize on the __ASSEMBLER__
macro that is provided by the compilers.

This is a completely mechanical patch (done with a simple "sed -i"
statement), with some manual fixups done later while rebasing the
patch.

Signed-off-by: Thomas Huth 
Acked-by: Heiko Carstens 
Link: https://lore.kernel.org/r/20250611140046.137739-3-thuth@redhat.com
Signed-off-by: Alexander Gordeev

s390/vdso: Switch to generic storage implementation

2025-02-21T08:54:02+00:00

The generic storage implementation provides the same features as the
custom one. However it can be shared between architectures, making
maintenance easier.

Co-developed-by: Nam Cao 
Signed-off-by: Nam Cao 
Signed-off-by: Thomas Weißschuh 
Signed-off-by: Thomas Gleixner 
Acked-by: Heiko Carstens 
Link: https://lore.kernel.org/all/20250204-vdso-store-rng-v3-12-13a4669dfc8c@linutronix.de

vdso: Rename struct arch_vdso_data to arch_vdso_time_data

2024-11-02T11:37:36+00:00

The struct arch_vdso_data is only about vdso time data. So rename it to
arch_vdso_time_data to make it obvious.
Non time-related data will be migrated out of these structs soon.

Signed-off-by: Nam Cao 
Signed-off-by: Thomas Gleixner 
Acked-by: Heiko Carstens  # s390
Link: https://lore.kernel.org/all/20241010-vdso-generic-base-v1-28-b64f0842d512@linutronix.de

s390/vdso: Remove timekeeper includes

2024-10-15T15:50:29+00:00

Since the generic VDSO clock mode storage is used, this header file is
unused and can be removed.

This avoids including a non-VDSO header while building the VDSO,
which can lead to compilation errors.

Also drop the comment which is out of date and in the wrong place.

Signed-off-by: Thomas Weißschuh 
Signed-off-by: Thomas Gleixner 
Acked-by: Heiko Carstens 
Link: https://lore.kernel.org/all/20241010-vdso-generic-arch_update_vsyscall-v1-6-7fe5a3ea4382@linutronix.de

s390/vdso: Wire up getrandom() vdso implementation

2024-09-13T18:57:31+00:00

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 
Reviewed-by: Harald Freudenberger 
Signed-off-by: Jason A. Donenfeld

vdso: Consolidate vdso_calc_delta()

2024-04-08T13:03:06+00:00

Consolidate vdso_calc_delta(), in preparation for further simplification.

Suggested-by: Thomas Gleixner 
Signed-off-by: Adrian Hunter 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/20240325064023.2997-2-adrian.hunter@intel.com

s390/vdso/data: Drop unnecessary header include

2024-02-20T19:56:00+00:00

vdso/datapage.h includes the architecture specific vdso/data.h header
file. So there is no need to do it also the other way round and including
the generic vdso/datapage.h header file inside the architecture specific
data.h header file.

Signed-off-by: Anna-Maria Behnsen 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Vincenzo Frascino 
Reviewed-by: Kees Cook 
Acked-by: Heiko Carstens 
Link: https://lore.kernel.org/r/20240219153939.75719-3-anna-maria@linutronix.de

s390/vdso: use system call functions

2021-07-27T07:39:15+00:00

Use system call functions instead of open-coding svc inline
assemblies. This is mostly to get rid of even more register asm
constructs.
Besides that, it makes the code also a bit easier to understand.
The generated code is identical to what is was before.

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

s390/vdso: add minimal compat vdso

2021-07-08T13:37:28+00:00

Add a small vdso for 31 bit compat application that provides
trampolines for calls to sigreturn,rt_sigreturn,syscall_restart.
This is requird for moving these syscalls away from the signal
frame to the vdso. Note that this patch effectively disables
CONFIG_COMPAT when using clang to compile the kernel. clang
doesn't support 31 bit mode.

We want to redirect sigreturn and restart_syscall to the vdso. However,
the kernel cannot parse the ELF vdso file, so we need to generate header
files which contain the offsets of the syscall instructions in the vdso
page.

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