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2025-09-29s390: Remove superfluous newlines from inline assembliesHeiko Carstens
Remove superfluous newlines from inline assemblies. Compilers use the number of lines of inline assemblies as heuristic for the complexity and inline decisions. Therefore inline assemblies should only contain as many lines as required. A lot of inline assemblies contain a superfluous newline for the last line. Remove such newlines to improve compiler inlining decisions. Suggested-by: Juergen Christ <jchrist@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Reviewed-by: Juergen Christ <jchrist@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
2025-09-25s390/diag324: Replace use of system_wq with system_percpu_wqMarco Crivellari
Currently if a user enqueue a work item using schedule_delayed_work() the used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to schedule_work() that is using system_wq and queue_work(), that makes use again of WORK_CPU_UNBOUND. This lack of consistentcy cannot be addressed without refactoring the API. system_wq is a per-CPU worqueue, yet nothing in its name tells about that CPU affinity constraint, which is very often not required by users. Make it clear by renaming system_wq to system_percpu_wq. queue_work() / queue_delayed_work() mod_delayed_work() will now use the new per-cpu wq. The old wq will be kept for a few release cylces. Suggested-by: Tejun Heo <tj@kernel.org> Signed-off-by: Marco Crivellari <marco.crivellari@suse.com> Acked-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
2025-03-18s390: Use inline qualifier for all EX_TABLE and ALTERNATIVE inline assembliesHeiko Carstens
Use asm_inline for all inline assemblies which make use of the EX_TABLE or ALTERNATIVE macros. These macros expand to many lines and the compiler assumes the number of lines within an inline assembly is the same as the number of instructions within an inline assembly. This has an effect on inlining and loop unrolling decisions. In order to avoid incorrect assumptions use asm_inline, which tells the compiler that an inline assembly has the smallest possible size. In order to avoid confusion when asm_inline should be used or not, since a couple of inline assemblies are quite large: the rule is to always use asm_inline whenever the EX_TABLE or ALTERNATIVE macro is used. In specific cases there may be reasons to not follow this guideline, but that should be documented with the corresponding code. Using the inline qualifier everywhere has only a small effect on the kernel image size: add/remove: 0/10 grow/shrink: 19/8 up/down: 1492/-1858 (-366) The only location where this seems to matter is load_unaligned_zeropad() from word-at-a-time.h where the compiler inlines more functions within the dcache code, which is indeed code where performance matters. Suggested-by: Juergen Christ <jchrist@linux.ibm.com> Reviewed-by: Juergen Christ <jchrist@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2025-01-15s390/diag: Add memory topology information via diag310Mete Durlu
Introduce diag310 and memory topology related subcodes. Provide memory topology information obtanied from diag310 to userspace via diag ioctl. Signed-off-by: Mete Durlu <meted@linux.ibm.com> Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
2024-12-17s390/diag: Move diag.c to diag specific folderSumanth Korikkar
Move implementation of s390 diagnose code to diag specific folder. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
2024-12-17s390/diag324: Retrieve power readings via diag 0x324Sumanth Korikkar
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 <hca@linux.ibm.com> Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
2024-12-17s390/diag: Create misc device /dev/diagSumanth Korikkar
Create a misc device /dev/diag to fetch diagnose specific information from the kernel and provide it to userspace. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>