From 587a1290a1af7bee6dbb40ebadb7a4d71e698baf Mon Sep 17 00:00:00 2001 From: Evan Green Date: Tue, 27 Feb 2024 14:56:43 -0800 Subject: riscv: Add and use alignment-ignorant memcpy For CPU implementations that can perform unaligned accesses with little or no performance penalty, create a memcpy implementation that does not bother aligning buffers. It will use a block of integer registers, a single integer register, and fall back to bytewise copy for the remainder. Signed-off-by: Evan Green Reviewed-by: Palmer Dabbelt Signed-off-by: Palmer Dabbelt --- sysdeps/riscv/memcpy.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) create mode 100644 sysdeps/riscv/memcpy.c (limited to 'sysdeps/riscv/memcpy.c') diff --git a/sysdeps/riscv/memcpy.c b/sysdeps/riscv/memcpy.c new file mode 100644 index 0000000000..20f9548c44 --- /dev/null +++ b/sysdeps/riscv/memcpy.c @@ -0,0 +1,63 @@ +/* Multiple versions of memcpy. + All versions must be listed in ifunc-impl-list.c. + Copyright (C) 2017-2024 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#if IS_IN (libc) +/* Redefine memcpy so that the compiler won't complain about the type + mismatch with the IFUNC selector in strong_alias, below. */ +# undef memcpy +# define memcpy __redirect_memcpy +# include +# include +# include +# include +# include + +# define INIT_ARCH() + +extern __typeof (__redirect_memcpy) __libc_memcpy; + +extern __typeof (__redirect_memcpy) __memcpy_generic attribute_hidden; +extern __typeof (__redirect_memcpy) __memcpy_noalignment attribute_hidden; + +static inline __typeof (__redirect_memcpy) * +select_memcpy_ifunc (uint64_t dl_hwcap, __riscv_hwprobe_t hwprobe_func) +{ + unsigned long long int value; + + INIT_ARCH (); + + if (__riscv_hwprobe_one (hwprobe_func, RISCV_HWPROBE_KEY_CPUPERF_0, &value) != 0) + return __memcpy_generic; + + if ((value & RISCV_HWPROBE_MISALIGNED_MASK) == RISCV_HWPROBE_MISALIGNED_FAST) + return __memcpy_noalignment; + + return __memcpy_generic; +} + +riscv_libc_ifunc (__libc_memcpy, select_memcpy_ifunc); + +# undef memcpy +strong_alias (__libc_memcpy, memcpy); +# ifdef SHARED +__hidden_ver1 (memcpy, __GI_memcpy, __redirect_memcpy) + __attribute__ ((visibility ("hidden"))) __attribute_copy__ (memcpy); +# endif + +#endif -- cgit 1.4.1