wireguard-linux/arch/s390/include/asm/vdso, branch stable

s390/processor: Implement cpu_relax() with cpu serialization

2026-05-20T07:48:04Z

There are many loops in the form of while (READ_ONCE(*somelocation)) cpu_relax(); Strictly speaking the architecture requires serialization instead of only a compiler barrier in the loop so the READ_ONCE() will see an updated value. However real hardware does not require this (see IBM z Systems Processor Optimization Primer - FAQ [1]), but it is still recommended to add serialization. Given that cpu_relax() is doing nothing useful, it does not hurt to add the single and fast instruction which makes sure that serialization happens, and such loops may be left a bit faster. [1] https://community.ibm.com/community/user/viewdocument/microprocessor-optimization-primer Reviewed-by: Alexander Gordeev Signed-off-by: Heiko Carstens Signed-off-by: Alexander Gordeev

s390/time: Remove in-kernel time steering

2025-07-21T10:41:55Z

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

2025-06-16T14:23:02Z

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

2025-02-21T08:54:02Z

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

2024-11-02T11:37:36Z

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

2024-10-15T15:50:29Z

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

2024-09-13T18:57:31Z

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()

2024-04-08T13:03:06Z

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

2024-02-20T19:56:00Z

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

2021-07-27T07:39:15Z

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