[PATCH v2 0/3] riscv: optimized mem* functions

From: Matteo Croce
Date: Wed Jun 16 2021 - 21:25:41 EST


From: Matteo Croce <mcroce@xxxxxxxxxxxxx>

Replace the assembly mem{cpy,move,set} with C equivalent.

Try to access RAM with the largest bit width possible, but without
doing unaligned accesses.

Tested on a BeagleV Starlight with a SiFive U74 core, where the
improvement is noticeable.

v1 -> v2:
- reduce the threshold from 64 to 16 bytes
- fix KASAN build
- optimize memset

Matteo Croce (3):
riscv: optimized memcpy
riscv: optimized memmove
riscv: optimized memset

arch/riscv/include/asm/string.h | 18 ++--
arch/riscv/kernel/Makefile | 1 -
arch/riscv/kernel/riscv_ksyms.c | 17 ----
arch/riscv/lib/Makefile | 4 +-
arch/riscv/lib/memcpy.S | 108 ---------------------
arch/riscv/lib/memmove.S | 64 -------------
arch/riscv/lib/memset.S | 113 ----------------------
arch/riscv/lib/string.c | 162 ++++++++++++++++++++++++++++++++
8 files changed, 172 insertions(+), 315 deletions(-)
delete mode 100644 arch/riscv/kernel/riscv_ksyms.c
delete mode 100644 arch/riscv/lib/memcpy.S
delete mode 100644 arch/riscv/lib/memmove.S
delete mode 100644 arch/riscv/lib/memset.S
create mode 100644 arch/riscv/lib/string.c

--
2.31.1