From nobody Thu Dec 18 19:06:22 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B6939C71153 for ; Sat, 2 Sep 2023 13:35:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232471AbjIBNfY (ORCPT ); Sat, 2 Sep 2023 09:35:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32774 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232267AbjIBNfX (ORCPT ); Sat, 2 Sep 2023 09:35:23 -0400 Received: from gnuweeb.org (gnuweeb.org [51.81.211.47]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7A84190 for ; Sat, 2 Sep 2023 06:35:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gnuweeb.org; s=default; t=1693661720; bh=BviSAhSuY5a+5JtffMjPSetuD8uWCAQ/gD+/+Xi1l/U=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=cMrXc1AO2CB4xdzsDMw6I+Vjo1rrfWkzd+x8I+jxJLS2I+B7Nl/uPHEm8LBDLZqDt eJz+FtfRWIReqM4vFUQS+yEyo4MMw3PwnpxOEbbqqzMpIyoeY+2gVKMjzCFgvP8yXS QYlJRm/++RzTrvkiTOf3K0IVxNv1WHEQQZFEKfovKGcCUB2yKsm5gTdYtBTf2qOzC5 YH0mVCQWbSGxoOBfQeq0EMVmM2GZ0cp/3YRsClwfRniHW+ACpqXxFUAxjMLhobHK5y rqGpNXgLwQKAgal2NDZw0ZVGp4pl0pcS2d8d7BvJTU4qL4RkM/AgkP3EXRG/M/LyTF h7JjO5Oa2b5Gw== Received: from localhost.localdomain (unknown [182.253.126.208]) by gnuweeb.org (Postfix) with ESMTPSA id 9823A24B3D2; Sat, 2 Sep 2023 20:35:16 +0700 (WIB) From: Ammar Faizi To: Willy Tarreau , =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= Cc: Ammar Faizi , David Laight , Nicholas Rosenberg , Alviro Iskandar Setiawan , Michael William Jonathan , GNU/Weeb Mailing List , Linux Kernel Mailing List Subject: [RFC PATCH v3 1/4] tools/nolibc: x86-64: Use `rep movsb` for `memcpy()` and `memmove()` Date: Sat, 2 Sep 2023 20:35:02 +0700 Message-Id: <20230902133505.2176434-2-ammarfaizi2@gnuweeb.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230902133505.2176434-1-ammarfaizi2@gnuweeb.org> References: <20230902133505.2176434-1-ammarfaizi2@gnuweeb.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Simplify memcpy() and memmove() on the x86-64 arch. The x86-64 arch has a 'rep movsb' instruction, which can perform memcpy() using only a single instruction, given: %rdi =3D destination %rsi =3D source %rcx =3D length Additionally, it can also handle the overlapping case by setting DF=3D1 (backward copy), which can be used as the memmove() implementation. Before this patch: ``` 00000000000010ab : 10ab: 48 89 f8 mov %rdi,%rax 10ae: 31 c9 xor %ecx,%ecx 10b0: 48 39 f7 cmp %rsi,%rdi 10b3: 48 83 d1 ff adc $0xffffffffffffffff,%rcx 10b7: 48 85 d2 test %rdx,%rdx 10ba: 74 25 je 10e1 10bc: 48 83 c9 01 or $0x1,%rcx 10c0: 48 39 f0 cmp %rsi,%rax 10c3: 48 c7 c7 ff ff ff ff mov $0xffffffffffffffff,%rdi 10ca: 48 0f 43 fa cmovae %rdx,%rdi 10ce: 48 01 cf add %rcx,%rdi 10d1: 44 8a 04 3e mov (%rsi,%rdi,1),%r8b 10d5: 44 88 04 38 mov %r8b,(%rax,%rdi,1) 10d9: 48 01 cf add %rcx,%rdi 10dc: 48 ff ca dec %rdx 10df: 75 f0 jne 10d1 10e1: c3 ret 00000000000010e2 : 10e2: 48 89 f8 mov %rdi,%rax 10e5: 48 85 d2 test %rdx,%rdx 10e8: 74 12 je 10fc 10ea: 31 c9 xor %ecx,%ecx 10ec: 40 8a 3c 0e mov (%rsi,%rcx,1),%dil 10f0: 40 88 3c 08 mov %dil,(%rax,%rcx,1) 10f4: 48 ff c1 inc %rcx 10f7: 48 39 ca cmp %rcx,%rdx 10fa: 75 f0 jne 10ec 10fc: c3 ret ``` After this patch: ``` // memmove is an alias for memcpy 000000000040133b : 40133b: 48 89 d1 mov %rdx,%rcx 40133e: 48 89 f8 mov %rdi,%rax 401341: 48 89 fa mov %rdi,%rdx 401344: 48 29 f2 sub %rsi,%rdx 401347: 48 39 ca cmp %rcx,%rdx 40134a: 72 03 jb 40134f 40134c: f3 a4 rep movsb %ds:(%rsi),%es:(%rdi) 40134e: c3 ret 40134f: 48 8d 7c 0f ff lea -0x1(%rdi,%rcx,1),%rdi 401354: 48 8d 74 0e ff lea -0x1(%rsi,%rcx,1),%rsi 401359: fd std 40135a: f3 a4 rep movsb %ds:(%rsi),%es:(%rdi) 40135c: fc cld 40135d: c3 ret ``` v3: - Make memmove as an alias for memcpy (Willy). - Make the forward copy the likely case (Alviro). v2: - Fix the broken memmove implementation (David). Link: https://lore.kernel.org/lkml/20230902062237.GA23141@1wt.eu Link: https://lore.kernel.org/lkml/5a821292d96a4dbc84c96ccdc6b5b666@AcuMS.a= culab.com Suggested-by: David Laight Signed-off-by: Ammar Faizi --- tools/include/nolibc/arch-x86_64.h | 29 +++++++++++++++++++++++++++++ tools/include/nolibc/string.h | 4 ++++ 2 files changed, 33 insertions(+) diff --git a/tools/include/nolibc/arch-x86_64.h b/tools/include/nolibc/arch= -x86_64.h index e5ccb926c90306b6..aece7d8951535a36 100644 --- a/tools/include/nolibc/arch-x86_64.h +++ b/tools/include/nolibc/arch-x86_64.h @@ -156,21 +156,50 @@ =20 /* startup code */ /* * x86-64 System V ABI mandates: * 1) %rsp must be 16-byte aligned right before the function call. * 2) The deepest stack frame should be zero (the %rbp). * */ void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer")))= __no_stack_protector _start(void) { __asm__ volatile ( "xor %ebp, %ebp\n" /* zero the stack frame = */ "mov %rsp, %rdi\n" /* save stack pointer to %rdi, as arg1 of _sta= rt_c */ "and $-16, %rsp\n" /* %rsp must be 16-byte aligned before call = */ "call _start_c\n" /* transfer to c runtime = */ "hlt\n" /* ensure it does not return = */ ); __builtin_unreachable(); } =20 +#define NOLIBC_ARCH_HAS_MEMMOVE +void *memmove(void *dst, const void *src, size_t len); + +#define NOLIBC_ARCH_HAS_MEMCPY +void *memcpy(void *dst, const void *src, size_t len); + +__asm__ ( +".section .text.nolibc_memmove_memcpy\n" +".weak memmove\n" +".weak memcpy\n" +"memmove:\n" +"memcpy:\n" + "movq %rdx, %rcx\n\t" + "movq %rdi, %rax\n\t" + "movq %rdi, %rdx\n\t" + "subq %rsi, %rdx\n\t" + "cmpq %rcx, %rdx\n\t" + "jb .Lbackward_copy\n\t" + "rep movsb\n\t" + "retq\n" +".Lbackward_copy:" + "leaq -1(%rdi, %rcx, 1), %rdi\n\t" + "leaq -1(%rsi, %rcx, 1), %rsi\n\t" + "std\n\t" + "rep movsb\n\t" + "cld\n\t" + "retq\n" +); + #endif /* _NOLIBC_ARCH_X86_64_H */ diff --git a/tools/include/nolibc/string.h b/tools/include/nolibc/string.h index 0c2e06c7c4772bc6..6eca267ec6fa7177 100644 --- a/tools/include/nolibc/string.h +++ b/tools/include/nolibc/string.h @@ -32,70 +32,74 @@ void *_nolibc_memcpy_up(void *dst, const void *src, siz= e_t len) { size_t pos =3D 0; =20 while (pos < len) { ((char *)dst)[pos] =3D ((const char *)src)[pos]; pos++; } return dst; } =20 static __attribute__((unused)) void *_nolibc_memcpy_down(void *dst, const void *src, size_t len) { while (len) { len--; ((char *)dst)[len] =3D ((const char *)src)[len]; } return dst; } =20 +#ifndef NOLIBC_ARCH_HAS_MEMMOVE /* might be ignored by the compiler without -ffreestanding, then found as * missing. */ __attribute__((weak,unused,section(".text.nolibc_memmove"))) void *memmove(void *dst, const void *src, size_t len) { size_t dir, pos; =20 pos =3D len; dir =3D -1; =20 if (dst < src) { pos =3D -1; dir =3D 1; } =20 while (len) { pos +=3D dir; ((char *)dst)[pos] =3D ((const char *)src)[pos]; len--; } return dst; } +#endif /* #ifndef NOLIBC_ARCH_HAS_MEMMOVE */ =20 +#ifndef NOLIBC_ARCH_HAS_MEMCPY /* must be exported, as it's used by libgcc on ARM */ __attribute__((weak,unused,section(".text.nolibc_memcpy"))) void *memcpy(void *dst, const void *src, size_t len) { return _nolibc_memcpy_up(dst, src, len); } +#endif /* #ifndef NOLIBC_ARCH_HAS_MEMCPY */ =20 /* might be ignored by the compiler without -ffreestanding, then found as * missing. */ __attribute__((weak,unused,section(".text.nolibc_memset"))) void *memset(void *dst, int b, size_t len) { char *p =3D dst; =20 while (len--) { /* prevent gcc from recognizing memset() here */ __asm__ volatile(""); *(p++) =3D b; } return dst; } =20 static __attribute__((unused)) char *strchr(const char *s, int c) { --=20 Ammar Faizi From nobody Thu Dec 18 19:06:22 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E0FE9C83F2C for ; Sat, 2 Sep 2023 13:35:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233042AbjIBNf2 (ORCPT ); Sat, 2 Sep 2023 09:35:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32806 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232267AbjIBNf1 (ORCPT ); Sat, 2 Sep 2023 09:35:27 -0400 Received: from gnuweeb.org (gnuweeb.org [51.81.211.47]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B5CA3E72 for ; Sat, 2 Sep 2023 06:35:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gnuweeb.org; s=default; t=1693661724; bh=00jMqkQPjVbfXwVpy1l1/4cyy6ihEZSgGusjZHhogmE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ORCwGQ70JFG+0hymb+wmcplU32w2of0dyQ0Ejy0HHyLnwBqwW5Hv2GiXKke3IIooz MOGTkzYigyNjxT/NoWJfntWqPHe5gBop5Mb8IBzloetvYg0euLoR1Xf6a6oh/hRL63 rNPA829EmusiIv94bbTPdeBgX4yjmOKO2+xDTskNPKVqoBIjeMNGreoVsBkcnsbeSO GqRyj0YFfAN5qKPpDj72IemLvmAlockKSQwGmDwtyuVa1fz5gmdIJjkRrihEBXh5XQ NGDT19vtkLXDkZiWGmLCB9MoLSkIZ0k8VhQfxX2FjTCsJm+18KUxJuPfzDMxRpPzBx 6xaUQDxwjHZnw== Received: from localhost.localdomain (unknown [182.253.126.208]) by gnuweeb.org (Postfix) with ESMTPSA id DB48524B3D8; Sat, 2 Sep 2023 20:35:20 +0700 (WIB) From: Ammar Faizi To: Willy Tarreau , =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= Cc: Ammar Faizi , David Laight , Nicholas Rosenberg , Alviro Iskandar Setiawan , Michael William Jonathan , GNU/Weeb Mailing List , Linux Kernel Mailing List Subject: [RFC PATCH v3 2/4] tools/nolibc: x86-64: Use `rep stosb` for `memset()` Date: Sat, 2 Sep 2023 20:35:03 +0700 Message-Id: <20230902133505.2176434-3-ammarfaizi2@gnuweeb.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230902133505.2176434-1-ammarfaizi2@gnuweeb.org> References: <20230902133505.2176434-1-ammarfaizi2@gnuweeb.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Simplify memset() on the x86-64 arch. The x86-64 arch has a 'rep stosb' instruction, which can perform memset() using only a single instruction, given: %al =3D value (just like the second argument of memset()) %rdi =3D destination %rcx =3D length Before this patch: ``` 00000000000010c9 : 10c9: 48 89 f8 mov %rdi,%rax 10cc: 48 85 d2 test %rdx,%rdx 10cf: 74 0e je 10df 10d1: 31 c9 xor %ecx,%ecx 10d3: 40 88 34 08 mov %sil,(%rax,%rcx,1) 10d7: 48 ff c1 inc %rcx 10da: 48 39 ca cmp %rcx,%rdx 10dd: 75 f4 jne 10d3 10df: c3 ret ``` After this patch: ``` 0000000000001511 : 1511: 96 xchg %eax,%esi 1512: 48 89 d1 mov %rdx,%rcx 1515: 57 push %rdi 1516: f3 aa rep stos %al,%es:(%rdi) 1518: 58 pop %rax 1519: c3 ret ``` v2: - Use pushq %rdi / popq %rax (Alviro). - Use xchg %eax, %esi (Willy). Link: https://lore.kernel.org/lkml/ZO9e6h2jjVIMpBJP@1wt.eu Suggested-by: Alviro Iskandar Setiawan Suggested-by: Willy Tarreau Signed-off-by: Ammar Faizi Reviewed-by: Alviro Iskandar Setiawan --- tools/include/nolibc/arch-x86_64.h | 13 +++++++++++++ tools/include/nolibc/string.h | 2 ++ 2 files changed, 15 insertions(+) diff --git a/tools/include/nolibc/arch-x86_64.h b/tools/include/nolibc/arch= -x86_64.h index aece7d8951535a36..1502db5c58fc0c87 100644 --- a/tools/include/nolibc/arch-x86_64.h +++ b/tools/include/nolibc/arch-x86_64.h @@ -162,44 +162,57 @@ * */ void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer")))= __no_stack_protector _start(void) { __asm__ volatile ( "xor %ebp, %ebp\n" /* zero the stack frame = */ "mov %rsp, %rdi\n" /* save stack pointer to %rdi, as arg1 of _sta= rt_c */ "and $-16, %rsp\n" /* %rsp must be 16-byte aligned before call = */ "call _start_c\n" /* transfer to c runtime = */ "hlt\n" /* ensure it does not return = */ ); __builtin_unreachable(); } =20 #define NOLIBC_ARCH_HAS_MEMMOVE void *memmove(void *dst, const void *src, size_t len); =20 #define NOLIBC_ARCH_HAS_MEMCPY void *memcpy(void *dst, const void *src, size_t len); =20 +#define NOLIBC_ARCH_HAS_MEMSET +void *memset(void *dst, int c, size_t len); + __asm__ ( ".section .text.nolibc_memmove_memcpy\n" ".weak memmove\n" ".weak memcpy\n" "memmove:\n" "memcpy:\n" "movq %rdx, %rcx\n\t" "movq %rdi, %rax\n\t" "movq %rdi, %rdx\n\t" "subq %rsi, %rdx\n\t" "cmpq %rcx, %rdx\n\t" "jb .Lbackward_copy\n\t" "rep movsb\n\t" "retq\n" ".Lbackward_copy:" "leaq -1(%rdi, %rcx, 1), %rdi\n\t" "leaq -1(%rsi, %rcx, 1), %rsi\n\t" "std\n\t" "rep movsb\n\t" "cld\n\t" "retq\n" + +".section .text.nolibc_memset\n" +".weak memset\n" +"memset:\n" + "xchgl %eax, %esi\n" + "movq %rdx, %rcx\n" + "pushq %rdi\n" + "rep stosb\n" + "popq %rax\n" + "retq\n" ); =20 #endif /* _NOLIBC_ARCH_X86_64_H */ diff --git a/tools/include/nolibc/string.h b/tools/include/nolibc/string.h index 6eca267ec6fa7177..1bad6121ef8c4ab5 100644 --- a/tools/include/nolibc/string.h +++ b/tools/include/nolibc/string.h @@ -67,55 +67,57 @@ void *memmove(void *dst, const void *src, size_t len) } =20 while (len) { pos +=3D dir; ((char *)dst)[pos] =3D ((const char *)src)[pos]; len--; } return dst; } #endif /* #ifndef NOLIBC_ARCH_HAS_MEMMOVE */ =20 #ifndef NOLIBC_ARCH_HAS_MEMCPY /* must be exported, as it's used by libgcc on ARM */ __attribute__((weak,unused,section(".text.nolibc_memcpy"))) void *memcpy(void *dst, const void *src, size_t len) { return _nolibc_memcpy_up(dst, src, len); } #endif /* #ifndef NOLIBC_ARCH_HAS_MEMCPY */ =20 +#ifndef NOLIBC_ARCH_HAS_MEMSET /* might be ignored by the compiler without -ffreestanding, then found as * missing. */ __attribute__((weak,unused,section(".text.nolibc_memset"))) void *memset(void *dst, int b, size_t len) { char *p =3D dst; =20 while (len--) { /* prevent gcc from recognizing memset() here */ __asm__ volatile(""); *(p++) =3D b; } return dst; } +#endif /* #ifndef NOLIBC_ARCH_HAS_MEMSET */ =20 static __attribute__((unused)) char *strchr(const char *s, int c) { while (*s) { if (*s =3D=3D (char)c) return (char *)s; s++; } return NULL; } =20 static __attribute__((unused)) int strcmp(const char *a, const char *b) { unsigned int c; int diff; =20 while (!(diff =3D (unsigned char)*a++ - (c =3D (unsigned char)*b++)) && c) ; --=20 Ammar Faizi From nobody Thu Dec 18 19:06:22 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 71801C83F2C for ; Sat, 2 Sep 2023 13:35:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232267AbjIBNfe (ORCPT ); Sat, 2 Sep 2023 09:35:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44276 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233077AbjIBNfd (ORCPT ); Sat, 2 Sep 2023 09:35:33 -0400 Received: from gnuweeb.org (gnuweeb.org [51.81.211.47]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5DFE8170D for ; Sat, 2 Sep 2023 06:35:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gnuweeb.org; s=default; t=1693661728; bh=wAfHXdyA6GZWEdNku2JSukYgPjxVsfGqEuLvT3ts0Qk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=MoKloUN1AB+uCPhoOkH+B8dTdUtg25rvGmSQ2zJRsOXnOfI8Eg9ojr5uoAteXuNgW sqDJSJww6eO+4F8T02uQHy+cXH7Dlnc6xS9vkapSxl7Ka403QURiktG/flguNnOSJm /neqy3u61I7f0G2fNssUOGeG0PGw3Vj2YE/v96ZudgCO8vNBiVGQRLXy59yxlfNSYm Am2O7w3Kct2QtYHseinj0W8O8Mei7KLr8hP6whpfSgrk0QY8Ri9d8xvjGxc1WiEDcv mI1Gq2LQFLWL25N6CPzwC21Xj/F6iIwEai/RqtldbwCU2zpbJXRkd1EWXEojbGQwr2 YqB7aXePs7vEw== Received: from localhost.localdomain (unknown [182.253.126.208]) by gnuweeb.org (Postfix) with ESMTPSA id 28FA924B3DD; Sat, 2 Sep 2023 20:35:24 +0700 (WIB) From: Ammar Faizi To: Willy Tarreau , =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= Cc: Ammar Faizi , David Laight , Nicholas Rosenberg , Alviro Iskandar Setiawan , Michael William Jonathan , GNU/Weeb Mailing List , Linux Kernel Mailing List Subject: [RFC PATCH v3 3/4] tools/nolibc: string: Remove the `_nolibc_memcpy_down()` function Date: Sat, 2 Sep 2023 20:35:04 +0700 Message-Id: <20230902133505.2176434-4-ammarfaizi2@gnuweeb.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230902133505.2176434-1-ammarfaizi2@gnuweeb.org> References: <20230902133505.2176434-1-ammarfaizi2@gnuweeb.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" This nolibc internal function is not used. Delete it. It was probably supposed to handle memmove(), but today the memmove() has its own implementation. Signed-off-by: Ammar Faizi Reviewed-by: Alviro Iskandar Setiawan --- tools/include/nolibc/string.h | 10 ---------- 1 file changed, 10 deletions(-) diff --git a/tools/include/nolibc/string.h b/tools/include/nolibc/string.h index 1bad6121ef8c4ab5..22dcb3f566baeefe 100644 --- a/tools/include/nolibc/string.h +++ b/tools/include/nolibc/string.h @@ -22,50 +22,40 @@ int memcmp(const void *s1, const void *s2, size_t n) int c1 =3D 0; =20 while (ofs < n && !(c1 =3D ((unsigned char *)s1)[ofs] - ((unsigned char *= )s2)[ofs])) { ofs++; } return c1; } =20 static __attribute__((unused)) void *_nolibc_memcpy_up(void *dst, const void *src, size_t len) { size_t pos =3D 0; =20 while (pos < len) { ((char *)dst)[pos] =3D ((const char *)src)[pos]; pos++; } return dst; } =20 -static __attribute__((unused)) -void *_nolibc_memcpy_down(void *dst, const void *src, size_t len) -{ - while (len) { - len--; - ((char *)dst)[len] =3D ((const char *)src)[len]; - } - return dst; -} - #ifndef NOLIBC_ARCH_HAS_MEMMOVE /* might be ignored by the compiler without -ffreestanding, then found as * missing. */ __attribute__((weak,unused,section(".text.nolibc_memmove"))) void *memmove(void *dst, const void *src, size_t len) { size_t dir, pos; =20 pos =3D len; dir =3D -1; =20 if (dst < src) { pos =3D -1; dir =3D 1; } =20 while (len) { pos +=3D dir; ((char *)dst)[pos] =3D ((const char *)src)[pos]; --=20 Ammar Faizi From nobody Thu Dec 18 19:06:22 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A61CBC83F2C for ; Sat, 2 Sep 2023 13:35:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233592AbjIBNfo (ORCPT ); Sat, 2 Sep 2023 09:35:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55920 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233120AbjIBNfo (ORCPT ); Sat, 2 Sep 2023 09:35:44 -0400 Received: from gnuweeb.org (gnuweeb.org [51.81.211.47]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4DC131738 for ; Sat, 2 Sep 2023 06:35:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gnuweeb.org; s=default; t=1693661733; bh=adKYv+UWCAtL6RnGzj9nIBJ/HQrhFBvKNcQpOXq1TGU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=fAbK/+f59o0nFsY7PmslyoS5pHnhg8H4k2Rp7HYy9XAeYFWockUwzwwYlFU+VM7iJ dStQbPfzEbfklMzNAV6CQphMOlwmNPgfCWTV2yMBvFnaUkmbekN0E5SrAg+pZxelcG FjcTf83uHhIY21i0fUb/XKo7155W9N87t9d/xjtXk8/GnjOC85b+Ifhq48kGkGoOcI eAIdmXAbq6W+gJfPmr1L10oq/Dxv+twRAbvliE0Ij+BcoeT8DI+8/kCAAYd7WFKLOd /01Nzb0HC63R90yc02TkGmg8ccA4a1Itzr0tiOFUVo5lXRuuoi5dnoB6BYWIttkSjJ Xw9iIO4Vwd6xA== Received: from localhost.localdomain (unknown [182.253.126.208]) by gnuweeb.org (Postfix) with ESMTPSA id 6CAC424B3E2; Sat, 2 Sep 2023 20:35:29 +0700 (WIB) From: Ammar Faizi To: Willy Tarreau , =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= Cc: Ammar Faizi , David Laight , Nicholas Rosenberg , Alviro Iskandar Setiawan , Michael William Jonathan , GNU/Weeb Mailing List , Linux Kernel Mailing List Subject: [RFC PATCH v3 4/4] tools/nolibc: string: Remove the `_nolibc_memcpy_up()` function Date: Sat, 2 Sep 2023 20:35:05 +0700 Message-Id: <20230902133505.2176434-5-ammarfaizi2@gnuweeb.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230902133505.2176434-1-ammarfaizi2@gnuweeb.org> References: <20230902133505.2176434-1-ammarfaizi2@gnuweeb.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" This function is only called by memcpy(), there is no real reason to have this wrapper. Delete this function and move the code to memcpy() directly. Signed-off-by: Ammar Faizi Reviewed-by: Alviro Iskandar Setiawan --- tools/include/nolibc/string.h | 20 +++++++------------- 1 file changed, 7 insertions(+), 13 deletions(-) diff --git a/tools/include/nolibc/string.h b/tools/include/nolibc/string.h index 22dcb3f566baeefe..a01c69dd495f550c 100644 --- a/tools/include/nolibc/string.h +++ b/tools/include/nolibc/string.h @@ -10,84 +10,78 @@ #include "std.h" =20 static void *malloc(size_t len); =20 /* * As much as possible, please keep functions alphabetically sorted. */ =20 static __attribute__((unused)) int memcmp(const void *s1, const void *s2, size_t n) { size_t ofs =3D 0; int c1 =3D 0; =20 while (ofs < n && !(c1 =3D ((unsigned char *)s1)[ofs] - ((unsigned char *= )s2)[ofs])) { ofs++; } return c1; } =20 -static __attribute__((unused)) -void *_nolibc_memcpy_up(void *dst, const void *src, size_t len) -{ - size_t pos =3D 0; - - while (pos < len) { - ((char *)dst)[pos] =3D ((const char *)src)[pos]; - pos++; - } - return dst; -} - #ifndef NOLIBC_ARCH_HAS_MEMMOVE /* might be ignored by the compiler without -ffreestanding, then found as * missing. */ __attribute__((weak,unused,section(".text.nolibc_memmove"))) void *memmove(void *dst, const void *src, size_t len) { size_t dir, pos; =20 pos =3D len; dir =3D -1; =20 if (dst < src) { pos =3D -1; dir =3D 1; } =20 while (len) { pos +=3D dir; ((char *)dst)[pos] =3D ((const char *)src)[pos]; len--; } return dst; } #endif /* #ifndef NOLIBC_ARCH_HAS_MEMMOVE */ =20 #ifndef NOLIBC_ARCH_HAS_MEMCPY /* must be exported, as it's used by libgcc on ARM */ __attribute__((weak,unused,section(".text.nolibc_memcpy"))) void *memcpy(void *dst, const void *src, size_t len) { - return _nolibc_memcpy_up(dst, src, len); + size_t pos =3D 0; + + while (pos < len) { + ((char *)dst)[pos] =3D ((const char *)src)[pos]; + pos++; + } + return dst; } #endif /* #ifndef NOLIBC_ARCH_HAS_MEMCPY */ =20 #ifndef NOLIBC_ARCH_HAS_MEMSET /* might be ignored by the compiler without -ffreestanding, then found as * missing. */ __attribute__((weak,unused,section(".text.nolibc_memset"))) void *memset(void *dst, int b, size_t len) { char *p =3D dst; =20 while (len--) { /* prevent gcc from recognizing memset() here */ __asm__ volatile(""); *(p++) =3D b; } return dst; } #endif /* #ifndef NOLIBC_ARCH_HAS_MEMSET */ --=20 Ammar Faizi