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bef64bcb94
Add an assembly implementation of strrchr() for RISC-V. This implementation minimizes instruction count and avoids unnecessary memory access to the stack. The performance benefits are most visible on small workloads (1-16 bytes) where the architectural savings in function overhead outweigh the execution time of the scan loop. Benchmark results (QEMU TCG, rv64): Length | Original (MB/s) | Optimized (MB/s) | Improvement -------|-----------------|------------------|------------ 1 B | 20 | 21 | +5.0% 7 B | 111 | 120 | +8.1% 16 B | 189 | 199 | +5.3% 512 B | 361 | 382 | +5.8% 4096 B | 388 | 391 | +0.8% Signed-off-by: Feng Jiang <jiangfeng@kylinos.cn> Tested-by: Joel Stanley <joel@jms.id.au> Link: https://patch.msgid.link/20260130025018.172925-9-jiangfeng@kylinos.cn Signed-off-by: Paul Walmsley <pjw@kernel.org>
54 lines
1.7 KiB
C
54 lines
1.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2013 Regents of the University of California
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*/
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#ifndef _ASM_RISCV_STRING_H
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#define _ASM_RISCV_STRING_H
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#include <linux/types.h>
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#include <linux/linkage.h>
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#define __HAVE_ARCH_MEMSET
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extern asmlinkage void *memset(void *, int, size_t);
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extern asmlinkage void *__memset(void *, int, size_t);
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#define __HAVE_ARCH_MEMCPY
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extern asmlinkage void *memcpy(void *, const void *, size_t);
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extern asmlinkage void *__memcpy(void *, const void *, size_t);
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#define __HAVE_ARCH_MEMMOVE
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extern asmlinkage void *memmove(void *, const void *, size_t);
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extern asmlinkage void *__memmove(void *, const void *, size_t);
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#if !(defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS))
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#define __HAVE_ARCH_STRCMP
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extern asmlinkage int strcmp(const char *cs, const char *ct);
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#define __HAVE_ARCH_STRLEN
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extern asmlinkage __kernel_size_t strlen(const char *);
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#define __HAVE_ARCH_STRNCMP
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extern asmlinkage int strncmp(const char *cs, const char *ct, size_t count);
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#define __HAVE_ARCH_STRNLEN
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extern asmlinkage __kernel_size_t strnlen(const char *, size_t);
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#define __HAVE_ARCH_STRCHR
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extern asmlinkage char *strchr(const char *, int);
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#define __HAVE_ARCH_STRRCHR
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extern asmlinkage char *strrchr(const char *, int);
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#endif
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/* For those files which don't want to check by kasan. */
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#if defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__)
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#define memcpy(dst, src, len) __memcpy(dst, src, len)
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#define memset(s, c, n) __memset(s, c, n)
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#define memmove(dst, src, len) __memmove(dst, src, len)
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#ifndef __NO_FORTIFY
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#define __NO_FORTIFY /* FORTIFY_SOURCE uses __builtin_memcpy, etc. */
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#endif
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#endif
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#endif /* _ASM_RISCV_STRING_H */
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