kernel/linux.git/arch/s390/include/asm/string.h, branch v6.19.11

s390: Remove superfluous newlines from inline assemblies

2025-09-29T11:52:08+00:00

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 Signed-off-by: Heiko Carstens Reviewed-by: Alexander Gordeev Reviewed-by: Juergen Christ Signed-off-by: Alexander Gordeev

s390/string: Remove strcpy() implementation

2025-04-30T09:41:28+00:00

Remove the optimized strcpy() library implementation. This doesn't make any difference since gcc recognizes all strcpy() usages anyway and uses the builtin variant. There is not a single branch to strcpy() within the generated kernel image, which also seems to be the reason why most other architectures don't have a strcpy() implementation anymore. Reviewed-by: Mikhail Zaslonko Signed-off-by: Heiko Carstens

s390/string: Remove optimized strncpy()

2025-04-17T13:16:10+00:00

There are hardly any strncpy() users left, therefore drop the optimized s390 variant. Acked-by: Alexander Gordeev Signed-off-by: Heiko Carstens

s390/string: add KMSAN support

2024-07-04T02:30:25+00:00

Add KMSAN support for the s390 implementations of the string functions. Do this similar to how it's already done for KASAN, except that the optimized memset{16,32,64}() functions need to be disabled: it's important for KMSAN to know that they initialized something. The way boot code is built with regard to string functions is problematic, since most files think it's configured with sanitizers, but boot/string.c doesn't. This creates various problems with the memset64() definitions, depending on whether the code is built with sanitizers or fortify. This should probably be streamlined, but in the meantime resolve the issues by introducing the IN_BOOT_STRING_C macro, similar to the existing IN_ARCH_STRING_C macro. Link: https://lkml.kernel.org/r/20240621113706.315500-33-iii@linux.ibm.com Signed-off-by: Ilya Leoshkevich Reviewed-by: Alexander Potapenko Acked-by: Heiko Carstens Cc: Alexander Gordeev Cc: Christian Borntraeger Cc: Christoph Lameter Cc: David Rientjes Cc: Dmitry Vyukov Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Joonsoo Kim Cc: Cc: Marco Elver Cc: Mark Rutland Cc: Masami Hiramatsu (Google) Cc: Pekka Enberg Cc: Roman Gushchin Cc: Steven Rostedt (Google) Cc: Sven Schnelle Cc: Vasily Gorbik Cc: Vlastimil Babka Signed-off-by: Andrew Morton

s390/kasan: remove override of mem*() functions

2023-04-19T15:24:16+00:00

The kasan mem*() functions are not used anymore since s390 has switched to GENERIC_ENTRY and commit 69d4c0d32186 ("entry, kasan, x86: Disallow overriding mem*() functions"). Therefore remove the now dead code, similar to x86. While at it also use the SYM* macros in mem.S. Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/string: use generic strlcpy

2021-10-26T13:21:30+00:00

The generic version of strlcpy is identical to the architecure specific variant. Therefore use the generic variant. Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/string: use generic strrchr

2021-10-26T13:21:30+00:00

Use generic strrchr instead of an optimized architecture specific variant. Performance of strrchr is not relevant for real life workloads, since the only user which may call this more frequently would be kbasename(). Suggested-by: Linus Torvalds Link: https://lore.kernel.org/lkml/CAHk-=whoe211F8ND-9hZvfnib0UA4gga8DZJ+YaBZNbE4fubdg@mail.gmail.com/ Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/string: get rid of register asm

2021-06-28T09:18:28+00:00

Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/kasan: provide uninstrumented __strlen

2019-08-21T10:58:52+00:00

s390 kasan code uses sclp_early_printk to report initialization failures. The code doing that should not be instrumented, because kasan shadow memory has not been set up yet. Even though sclp_early_core.c is compiled with instrumentation disabled it uses strlen function, which is instrumented and would produce shadow memory access if used. To avoid that, introduce uninstrumented __strlen function to be used instead. Before commit 7e0d92f00246 ("s390/kasan: improve string/memory functions checks") few string functions (including strlen) were escaping kasan instrumentation due to usage of platform specific versions which are implemented in inline assembly. Fixes: 7e0d92f00246 ("s390/kasan: improve string/memory functions checks") Acked-by: Ilya Leoshkevich Signed-off-by: Vasily Gorbik

s390/kasan: improve string/memory functions checks

2019-01-18T08:34:18+00:00

Avoid using arch specific implementations of string/memory functions with KASAN since gcc cannot instrument asm code memory accesses and many bugs could be missed. Acked-by: Heiko Carstens Signed-off-by: Vasily Gorbik Signed-off-by: Martin Schwidefsky