linux-kernel - [PATCH 0/3] lib/string: optimized mem* functions

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Date:   Fri, 25 Jun 2021 03:01:57 +0200
From:   Matteo Croce <mcroce@...ux.microsoft.com>
To:     linux-kernel@...r.kernel.org, Nick Kossifidis <mick@....forth.gr>,
        Guo Ren <guoren@...nel.org>,
        Christoph Hellwig <hch@...radead.org>,
        David Laight <David.Laight@...lab.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Emil Renner Berthing <kernel@...il.dk>,
        Drew Fustini <drew@...gleboard.org>
Cc:     linux-arch@...r.kernel.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        linux-riscv@...ts.infradead.org
Subject: [PATCH 0/3] lib/string: optimized mem* functions

From: Matteo Croce <mcroce@...rosoft.com>

Rewrite the generic mem{cpy,move,set} so that memory is accessed with
the widest size possible, but without doing unaligned accesses.

This was originally posted as C string functions for RISC-V[1], but as
there was no specific RISC-V code, it was proposed for the generic
lib/string.c implementation.

Tested on RISC-V and on x86_64 by undefining __HAVE_ARCH_MEM{CPY,SET,MOVE}
and HAVE_EFFICIENT_UNALIGNED_ACCESS.

Further testing on big endian machines will be appreciated, as I don't
have such hardware at the moment.

[1] https://lore.kernel.org/linux-riscv/20210617152754.17960-1-mcroce@linux.microsoft.com/

Matteo Croce (3):
  lib/string: optimized memcpy
  lib/string: optimized memmove
  lib/string: optimized memset

 lib/string.c | 129 ++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 112 insertions(+), 17 deletions(-)

-- 
2.31.1