From: Heiko Carstens <hca@linux.ibm.com>
To: Alexander Gordeev <agordeev@linux.ibm.com>,
Sven Schnelle <svens@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Juergen Christ <jchrist@linux.ibm.com>
Cc: linux-s390@vger.kernel.org
Subject: [PATCH v2 0/8]
Date: Mon, 8 Jun 2026 07:37:46 +0200 [thread overview]
Message-ID: <20260608053754.571282-1-hca@linux.ibm.com> (raw)
v2:
Address various Shashiko findings [2]:
- Off by one comparison bug, which leads to slow path for memmove()
- Incorrect ifdef around __memset()
- Incorrect commit description for memmove() conversion
- Missing noinstr for tishift functions
- Missing header guard for tishift header file
v1:
While working on something else I stumbled again across the various mem*()
helper functions, which were implemented in assembler to avoid recursive
calls [1], when using the compiler's builtin functions.
Convert the functions back to C using inline assemblies, which makes them
hopefully a bit more readable and maintainable. Also improve the memmove()
implementation by using the mvcrl instruction for the backward copy case.
Thanks,
Heiko
[1] commit 535c611ddd3e ("s390/string: provide asm lib functions for memcpy and memcmp")
[2] https://sashiko.dev/#/patchset/20260607162937.2927356-1-hca%40linux.ibm.com
Heiko Carstens (8):
s390/purgatory: Enforce z10 minimum architecture level
s390: Add .noinstr.text to boot and purgatory linker scripts
s390/string: Convert memmove() to C
s390/string: Convert memset() to C
s390/string: Convert memcpy() to C
s390/string: Convert memset(16|32|64)() to C
s390/memmove: Optimize backward copy case
s390/tishift: Convert __ashlti3(), __ashrti3(), __lshrti3() to C
arch/s390/boot/Makefile | 2 +-
arch/s390/boot/mem.S | 2 -
arch/s390/boot/string.c | 6 +-
arch/s390/boot/vmlinux.lds.S | 1 +
arch/s390/include/asm/asm-prototypes.h | 4 -
arch/s390/lib/Makefile | 1 -
arch/s390/lib/mem.S | 192 ----------------------
arch/s390/lib/string.c | 210 +++++++++++++++++++++++++
arch/s390/lib/tishift.S | 63 --------
arch/s390/lib/tishift.c | 64 ++++++++
arch/s390/lib/tishift.h | 9 ++
arch/s390/purgatory/Makefile | 9 +-
arch/s390/purgatory/purgatory.lds.S | 1 +
13 files changed, 291 insertions(+), 273 deletions(-)
delete mode 100644 arch/s390/boot/mem.S
delete mode 100644 arch/s390/lib/mem.S
delete mode 100644 arch/s390/lib/tishift.S
create mode 100644 arch/s390/lib/tishift.c
create mode 100644 arch/s390/lib/tishift.h
--
2.53.0
next reply other threads:[~2026-06-08 5:38 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-08 5:37 Heiko Carstens [this message]
2026-06-08 5:37 ` [PATCH v2 1/8] s390/purgatory: Enforce z10 minimum architecture level Heiko Carstens
2026-06-08 5:37 ` [PATCH v2 2/8] s390: Add .noinstr.text to boot and purgatory linker scripts Heiko Carstens
2026-06-08 5:37 ` [PATCH v2 3/8] s390/string: Convert memmove() to C Heiko Carstens
2026-06-08 8:01 ` Juergen Christ
2026-06-08 9:14 ` Heiko Carstens
2026-06-08 9:20 ` Juergen Christ
2026-06-08 5:37 ` [PATCH v2 4/8] s390/string: Convert memset() " Heiko Carstens
2026-06-08 5:37 ` [PATCH v2 5/8] s390/string: Convert memcpy() " Heiko Carstens
2026-06-08 5:37 ` [PATCH v2 6/8] s390/string: Convert memset(16|32|64)() " Heiko Carstens
2026-06-08 5:37 ` [PATCH v2 7/8] s390/memmove: Optimize backward copy case Heiko Carstens
2026-06-08 5:37 ` [PATCH v2 8/8] s390/tishift: Convert __ashlti3(), __ashrti3(), __lshrti3() to C Heiko Carstens
2026-06-08 8:19 ` Juergen Christ
2026-06-08 8:55 ` Heiko Carstens
2026-06-08 9:24 ` [PATCH v2 0/8] Juergen Christ
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