From 2a8b65c63734644f67b79c0b85626494f24db74b Mon Sep 17 00:00:00 2001 From: Matteo Croce Date: Wed, 29 Sep 2021 19:22:34 +0200 Subject: [PATCH] riscv: optimized memset The generic memset is defined as a byte at time write. This is always safe, but it's slower than a 4 byte or even 8 byte write. Write a generic memset which fills the data one byte at time until the destination is aligned, then fills using the largest size allowed, and finally fills the remaining data one byte at time. Signed-off-by: Matteo Croce Signed-off-by: Emil Renner Berthing --- arch/riscv/include/asm/string.h | 8 +-- arch/riscv/kernel/Makefile | 1 - arch/riscv/kernel/riscv_ksyms.c | 13 ----- arch/riscv/lib/Makefile | 1 - arch/riscv/lib/memset.S | 113 ---------------------------------------- arch/riscv/lib/string.c | 41 +++++++++++++++ arch/riscv/purgatory/Makefile | 5 +- 7 files changed, 44 insertions(+), 138 deletions(-) delete mode 100644 arch/riscv/kernel/riscv_ksyms.c delete mode 100644 arch/riscv/lib/memset.S diff --git a/arch/riscv/include/asm/string.h b/arch/riscv/include/asm/string.h index 0212046..3b79b14 100644 --- a/arch/riscv/include/asm/string.h +++ b/arch/riscv/include/asm/string.h @@ -6,13 +6,9 @@ #ifndef _ASM_RISCV_STRING_H #define _ASM_RISCV_STRING_H -#include -#include - #define __HAVE_ARCH_MEMSET -extern asmlinkage void *memset(void *, int, size_t); -extern asmlinkage void *__memset(void *, int, size_t); - +extern void *memset(void *s, int c, size_t count); +extern void *__memset(void *s, int c, size_t count); #define __HAVE_ARCH_MEMCPY extern void *memcpy(void *dest, const void *src, size_t count); extern void *__memcpy(void *dest, const void *src, size_t count); diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile index db6e4b1..eea7ce0 100644 --- a/arch/riscv/kernel/Makefile +++ b/arch/riscv/kernel/Makefile @@ -46,7 +46,6 @@ obj-y += syscall_table.o obj-y += sys_riscv.o obj-y += time.o obj-y += traps.o -obj-y += riscv_ksyms.o obj-y += stacktrace.o obj-y += cacheinfo.o obj-y += patch.o diff --git a/arch/riscv/kernel/riscv_ksyms.c b/arch/riscv/kernel/riscv_ksyms.c deleted file mode 100644 index 361565c..0000000 --- a/arch/riscv/kernel/riscv_ksyms.c +++ /dev/null @@ -1,13 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-only -/* - * Copyright (C) 2017 Zihao Yu - */ - -#include -#include - -/* - * Assembly functions that may be used (directly or indirectly) by modules - */ -EXPORT_SYMBOL(memset); -EXPORT_SYMBOL(__memset); diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile index 9166b61..482e281 100644 --- a/arch/riscv/lib/Makefile +++ b/arch/riscv/lib/Makefile @@ -1,6 +1,5 @@ # SPDX-License-Identifier: GPL-2.0-only lib-y += delay.o -lib-y += memset.o lib-$(CONFIG_MMU) += uaccess.o lib-$(CONFIG_64BIT) += tishift.o lib-y += string.o diff --git a/arch/riscv/lib/memset.S b/arch/riscv/lib/memset.S deleted file mode 100644 index 34c5360..0000000 --- a/arch/riscv/lib/memset.S +++ /dev/null @@ -1,113 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0-only */ -/* - * Copyright (C) 2013 Regents of the University of California - */ - - -#include -#include - -/* void *memset(void *, int, size_t) */ -ENTRY(__memset) -WEAK(memset) - move t0, a0 /* Preserve return value */ - - /* Defer to byte-oriented fill for small sizes */ - sltiu a3, a2, 16 - bnez a3, 4f - - /* - * Round to nearest XLEN-aligned address - * greater than or equal to start address - */ - addi a3, t0, SZREG-1 - andi a3, a3, ~(SZREG-1) - beq a3, t0, 2f /* Skip if already aligned */ - /* Handle initial misalignment */ - sub a4, a3, t0 -1: - sb a1, 0(t0) - addi t0, t0, 1 - bltu t0, a3, 1b - sub a2, a2, a4 /* Update count */ - -2: /* Duff's device with 32 XLEN stores per iteration */ - /* Broadcast value into all bytes */ - andi a1, a1, 0xff - slli a3, a1, 8 - or a1, a3, a1 - slli a3, a1, 16 - or a1, a3, a1 -#ifdef CONFIG_64BIT - slli a3, a1, 32 - or a1, a3, a1 -#endif - - /* Calculate end address */ - andi a4, a2, ~(SZREG-1) - add a3, t0, a4 - - andi a4, a4, 31*SZREG /* Calculate remainder */ - beqz a4, 3f /* Shortcut if no remainder */ - neg a4, a4 - addi a4, a4, 32*SZREG /* Calculate initial offset */ - - /* Adjust start address with offset */ - sub t0, t0, a4 - - /* Jump into loop body */ - /* Assumes 32-bit instruction lengths */ - la a5, 3f -#ifdef CONFIG_64BIT - srli a4, a4, 1 -#endif - add a5, a5, a4 - jr a5 -3: - REG_S a1, 0(t0) - REG_S a1, SZREG(t0) - REG_S a1, 2*SZREG(t0) - REG_S a1, 3*SZREG(t0) - REG_S a1, 4*SZREG(t0) - REG_S a1, 5*SZREG(t0) - REG_S a1, 6*SZREG(t0) - REG_S a1, 7*SZREG(t0) - REG_S a1, 8*SZREG(t0) - REG_S a1, 9*SZREG(t0) - REG_S a1, 10*SZREG(t0) - REG_S a1, 11*SZREG(t0) - REG_S a1, 12*SZREG(t0) - REG_S a1, 13*SZREG(t0) - REG_S a1, 14*SZREG(t0) - REG_S a1, 15*SZREG(t0) - REG_S a1, 16*SZREG(t0) - REG_S a1, 17*SZREG(t0) - REG_S a1, 18*SZREG(t0) - REG_S a1, 19*SZREG(t0) - REG_S a1, 20*SZREG(t0) - REG_S a1, 21*SZREG(t0) - REG_S a1, 22*SZREG(t0) - REG_S a1, 23*SZREG(t0) - REG_S a1, 24*SZREG(t0) - REG_S a1, 25*SZREG(t0) - REG_S a1, 26*SZREG(t0) - REG_S a1, 27*SZREG(t0) - REG_S a1, 28*SZREG(t0) - REG_S a1, 29*SZREG(t0) - REG_S a1, 30*SZREG(t0) - REG_S a1, 31*SZREG(t0) - addi t0, t0, 32*SZREG - bltu t0, a3, 3b - andi a2, a2, SZREG-1 /* Update count */ - -4: - /* Handle trailing misalignment */ - beqz a2, 6f - add a3, t0, a2 -5: - sb a1, 0(t0) - addi t0, t0, 1 - bltu t0, a3, 5b -6: - ret -END(__memset) diff --git a/arch/riscv/lib/string.c b/arch/riscv/lib/string.c index bd52581..7fc9ec5c 100644 --- a/arch/riscv/lib/string.c +++ b/arch/riscv/lib/string.c @@ -112,3 +112,44 @@ EXPORT_SYMBOL(__memmove); void *memmove(void *dest, const void *src, size_t count) __weak __alias(__memmove); EXPORT_SYMBOL(memmove); + +void *__memset(void *s, int c, size_t count) +{ + union types dest = { .as_u8 = s }; + + if (count >= MIN_THRESHOLD) { + unsigned long cu = (unsigned long)c; + + /* Compose an ulong with 'c' repeated 4/8 times */ +#ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER + cu *= 0x0101010101010101UL; +#else + cu |= cu << 8; + cu |= cu << 16; + /* Suppress warning on 32 bit machines */ + cu |= (cu << 16) << 16; +#endif + if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) { + /* + * Fill the buffer one byte at time until + * the destination is word aligned. + */ + for (; count && dest.as_uptr & WORD_MASK; count--) + *dest.as_u8++ = c; + } + + /* Copy using the largest size allowed */ + for (; count >= BYTES_LONG; count -= BYTES_LONG) + *dest.as_ulong++ = cu; + } + + /* copy the remainder */ + while (count--) + *dest.as_u8++ = c; + + return s; +} +EXPORT_SYMBOL(__memset); + +void *memset(void *s, int c, size_t count) __weak __alias(__memset); +EXPORT_SYMBOL(memset); diff --git a/arch/riscv/purgatory/Makefile b/arch/riscv/purgatory/Makefile index cdac455..59991f8 100644 --- a/arch/riscv/purgatory/Makefile +++ b/arch/riscv/purgatory/Makefile @@ -1,7 +1,7 @@ # SPDX-License-Identifier: GPL-2.0 OBJECT_FILES_NON_STANDARD := y -purgatory-y := purgatory.o sha256.o entry.o string.o ctype.o rvstring.o memset.o +purgatory-y := purgatory.o sha256.o entry.o string.o ctype.o rvstring.o targets += $(purgatory-y) PURGATORY_OBJS = $(addprefix $(obj)/,$(purgatory-y)) @@ -15,9 +15,6 @@ $(obj)/ctype.o: $(srctree)/lib/ctype.c FORCE $(obj)/rvstring.o: $(srctree)/arch/riscv/lib/string.c FORCE $(call if_changed_rule,cc_o_c) -$(obj)/memset.o: $(srctree)/arch/riscv/lib/memset.S FORCE - $(call if_changed_rule,as_o_S) - $(obj)/sha256.o: $(srctree)/lib/crypto/sha256.c FORCE $(call if_changed_rule,cc_o_c) -- 2.7.4