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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 0/8] s390/string: Convert various functions to C
Date: Sun,  7 Jun 2026 18:29:29 +0200	[thread overview]
Message-ID: <20260607162937.2927356-1-hca@linux.ibm.com> (raw)

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")

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 memset() 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                |   8 +
 arch/s390/purgatory/Makefile           |   9 +-
 arch/s390/purgatory/purgatory.lds.S    |   1 +
 13 files changed, 290 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


             reply	other threads:[~2026-06-07 16:29 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-07 16:29 Heiko Carstens [this message]
2026-06-07 16:29 ` [PATCH 1/8] s390/purgatory: Enforce z10 minimum architecture level Heiko Carstens
2026-06-07 16:29 ` [PATCH 2/8] s390: Add .noinstr.text to boot and purgatory linker scripts Heiko Carstens
2026-06-07 16:29 ` [PATCH 3/8] s390/string: Convert memmove() to C Heiko Carstens
2026-06-07 16:29 ` [PATCH 4/8] s390/string: Convert memset() " Heiko Carstens
2026-06-07 16:29 ` [PATCH 5/8] " Heiko Carstens
2026-06-07 16:29 ` [PATCH 6/8] s390/string: Convert memset(16|32|64)() " Heiko Carstens
2026-06-07 16:29 ` [PATCH 7/8] s390/memmove: Optimize backward copy case Heiko Carstens
2026-06-07 16:29 ` [PATCH 8/8] s390/tishift: Convert __ashlti3(), __ashrti3(), __lshrti3() to C Heiko Carstens

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