linux.git/arch/s390/include/asm/string.h, branch v6.16

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

s390/kasan: replace some memory functions

2018-10-09T09:21:18+00:00

Follow the common kasan approach:

    "KASan replaces memory functions with manually instrumented
    variants.  Original functions declared as weak symbols so strong
    definitions in mm/kasan/kasan.c could replace them. Original
    functions have aliases with '__' prefix in name, so we could call
    non-instrumented variant if needed."

Signed-off-by: Vasily Gorbik 
Signed-off-by: Martin Schwidefsky