From nobody Fri Dec 19 05:01:41 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 6919ACA0FF8 for ; Sat, 2 Sep 2023 05:51:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351586AbjIBFvM (ORCPT ); Sat, 2 Sep 2023 01:51:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51678 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351582AbjIBFvL (ORCPT ); Sat, 2 Sep 2023 01:51:11 -0400 Received: from gnuweeb.org (gnuweeb.org [51.81.211.47]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3F46D10F4 for ; Fri, 1 Sep 2023 22:51:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gnuweeb.org; s=default; t=1693633867; bh=NQWKtbuv3O/n7tmkR45L8qVDPkXuYuS7O3N5c4Qqga8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=aRA5svkaD5fuRYhfod9nEh4DoKa3Vz/4HH86s8cDl+Gag9qyOE+qzSdbive2LxJbf 4OC3O2RmmE/YZ2mD9xitl5DB6+u89q2VQTUIQN7d5V+prORNjuUphgA5+WwXeumaZr pwAjGQ0+cncze+ny6F7T0BAHp3A/AuHVFXguDi2YgfhWwdeFciegZFZlnDIz+2Y0hg U/wPgUoAl3s+y+Bmk7Rij+fUsBT43HGA1CcMJ8mGJ/TEUoYF872Fb5AmjTQk4yWZIG 4vkMsOHwN+vayFlQmKRWUVFPq6pJvxkV1rMY4O/LaPuEbr7jn5qYicfsyNnho3rw8j Pmj/1xOIncIAQ== Received: from localhost.localdomain (unknown [182.253.126.208]) by gnuweeb.org (Postfix) with ESMTPSA id 3635624B39E; Sat, 2 Sep 2023 12:51:03 +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 v2 1/4] tools/nolibc: x86-64: Use `rep movsb` for `memcpy()` and `memmove()` Date: Sat, 2 Sep 2023 12:50:42 +0700 Message-Id: <20230902055045.2138405-2-ammarfaizi2@gnuweeb.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230902055045.2138405-1-ammarfaizi2@gnuweeb.org> References: <20230902055045.2138405-1-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: ``` 0000000000401040 : 401040: 48 89 d1 mov %rdx,%rcx 401043: 48 89 fa mov %rdi,%rdx 401046: 48 89 f8 mov %rdi,%rax 401049: 48 29 f2 sub %rsi,%rdx 40104c: 48 39 ca cmp %rcx,%rdx 40104f: 73 0f jae 401060 401051: 48 8d 7c 0f ff lea -0x1(%rdi,%rcx,1),%rdi 401056: 48 8d 74 0e ff lea -0x1(%rsi,%rcx,1),%rsi 40105b: fd std 40105c: f3 a4 rep movsb %ds:(%rsi),%es:(%rdi) 40105e: fc cld 40105f: c3 ret 401060: f3 a4 rep movsb %ds:(%rsi),%es:(%rdi) 401062: c3 ret 0000000000401063 : 401063: 48 89 f8 mov %rdi,%rax 401066: 48 89 d1 mov %rdx,%rcx 401069: f3 a4 rep movsb %ds:(%rsi),%es:(%rdi) 40106b: c3 ret ``` 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 | 35 ++++++++++++++++++++++++++++++ tools/include/nolibc/string.h | 4 ++++ 2 files changed, 39 insertions(+) diff --git a/tools/include/nolibc/arch-x86_64.h b/tools/include/nolibc/arch= -x86_64.h index e5ccb926c90306b6..297ffa364b2312eb 100644 --- a/tools/include/nolibc/arch-x86_64.h +++ b/tools/include/nolibc/arch-x86_64.h @@ -156,21 +156,56 @@ =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\n" +".weak memmove\n" +"memmove:\n" + "movq %rdx, %rcx\n" + "movq %rdi, %rdx\n" + "movq %rdi, %rax\n" + "subq %rsi, %rdx\n" + "cmpq %rcx, %rdx\n" + "jnb .Lforward_copy\n" + "leaq -1(%rdi, %rcx, 1), %rdi\n" + "leaq -1(%rsi, %rcx, 1), %rsi\n" + "std\n" + "rep movsb\n" + "cld\n" + "retq\n" +".Lforward_copy:\n" + "rep movsb\n" + "retq\n" + +".section .text.nolibc_memcpy\n" +".weak memcpy\n" +"memcpy:\n" + "movq %rdi, %rax\n" + "movq %rdx, %rcx\n" + "rep movsb\n" + "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 Fri Dec 19 05:01:41 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 7AF74CA0FFD for ; Sat, 2 Sep 2023 05:51:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351592AbjIBFvS (ORCPT ); Sat, 2 Sep 2023 01:51:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33444 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351582AbjIBFvP (ORCPT ); Sat, 2 Sep 2023 01:51:15 -0400 Received: from gnuweeb.org (gnuweeb.org [51.81.211.47]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9F55510F6 for ; Fri, 1 Sep 2023 22:51:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gnuweeb.org; s=default; t=1693633872; bh=x9sDKPf10aSubQx2+ufgoe1wqMoNjeL92ALh+yOhHx4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=o4zLcBRCrL11CYdrGjjX08nuRkrk+qRYSsiofmENoJwnRI3qMFfSlW3dPmKX7ikJe D1O7lw53EpIDE5jAlrAAQiSm/ypgfp1nnd6zka7mf6bKzzu+hNA1FSJGo8zt+c3Vvt sQJDXVDYq2wshI46JktOqy+8wSgbJR2BYMi4fbt7XybqhB2j5uSibWY8qsHVjyEAxX 7WpcJNZvJHAAPoFWao9Jyalab+t4IJqMMetzKzRTLB6gAn3Zvjyyc9fFQr4MSXOd7P 0HvQktXpoIhNfCNH2+PRh/xHZANu2iqNSe4Mgz4WQdjJNbC4HLkXDuOPjHR7pKc2Pu b8z8wkOXW4JtQ== Received: from localhost.localdomain (unknown [182.253.126.208]) by gnuweeb.org (Postfix) with ESMTPSA id A5B8624B3A7; Sat, 2 Sep 2023 12:51:08 +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 v2 2/4] tools/nolibc: x86-64: Use `rep stosb` for `memset()` Date: Sat, 2 Sep 2023 12:50:43 +0700 Message-Id: <20230902055045.2138405-3-ammarfaizi2@gnuweeb.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230902055045.2138405-1-ammarfaizi2@gnuweeb.org> References: <20230902055045.2138405-1-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 code size shrink: - 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 --- 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 297ffa364b2312eb..ed01b130e25c6740 100644 --- a/tools/include/nolibc/arch-x86_64.h +++ b/tools/include/nolibc/arch-x86_64.h @@ -162,50 +162,63 @@ * */ 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\n" ".weak memmove\n" "memmove:\n" "movq %rdx, %rcx\n" "movq %rdi, %rdx\n" "movq %rdi, %rax\n" "subq %rsi, %rdx\n" "cmpq %rcx, %rdx\n" "jnb .Lforward_copy\n" "leaq -1(%rdi, %rcx, 1), %rdi\n" "leaq -1(%rsi, %rcx, 1), %rsi\n" "std\n" "rep movsb\n" "cld\n" "retq\n" ".Lforward_copy:\n" "rep movsb\n" "retq\n" =20 ".section .text.nolibc_memcpy\n" ".weak memcpy\n" "memcpy:\n" "movq %rdi, %rax\n" "movq %rdx, %rcx\n" "rep movsb\n" "retq\n" + +".section .text.nolibc_memset\n" +".weak memset\n" +"memset:\n" + "xchg %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 Fri Dec 19 05:01:41 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 8AD0BCA0FFC for ; Sat, 2 Sep 2023 05:51:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351601AbjIBFvY (ORCPT ); Sat, 2 Sep 2023 01:51:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33462 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351593AbjIBFvV (ORCPT ); Sat, 2 Sep 2023 01:51:21 -0400 Received: from gnuweeb.org (gnuweeb.org [51.81.211.47]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2E2AD1703 for ; Fri, 1 Sep 2023 22:51:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gnuweeb.org; s=default; t=1693633876; bh=wAfHXdyA6GZWEdNku2JSukYgPjxVsfGqEuLvT3ts0Qk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=In2+PoLeMiRv9KKUXN3cUjeymX4Gtga8saNBekvRy+tDOPY6Nu0BHTvd+ASgZYvK9 Z1O+yWWzkK1vemeW5QqhjWkZgAvZdOvX7R1ohVix4elg1ZSmh+wdGBEcoiVV+XD3pq r7pqW+Q2wfIAoLVo4gU7OnHAikkaJflg7niFDWlLWoeZiJTcZHr1Uxtnm8zS9EpVEY gVm4jyxSmhpqVAPgdTSYZjt9IaMHqQ6qf36V44tMcYjR4/+sKVY6wEVlWytDEqilI7 M0S8k0pAiyu8jnoW6zQuddDcttOg22kiIDaOrig5tLVu7a+OTg6cdGiEihghlcm1fR cCpWQacNqSiLw== Received: from localhost.localdomain (unknown [182.253.126.208]) by gnuweeb.org (Postfix) with ESMTPSA id 2253124B3AD; Sat, 2 Sep 2023 12:51:12 +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 v2 3/4] tools/nolibc: string: Remove the `_nolibc_memcpy_down()` function Date: Sat, 2 Sep 2023 12:50:44 +0700 Message-Id: <20230902055045.2138405-4-ammarfaizi2@gnuweeb.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230902055045.2138405-1-ammarfaizi2@gnuweeb.org> References: <20230902055045.2138405-1-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 --- 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 Fri Dec 19 05:01:41 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 56EDBCA0FF6 for ; Sat, 2 Sep 2023 05:51:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351604AbjIBFva (ORCPT ); Sat, 2 Sep 2023 01:51:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58028 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351582AbjIBFv3 (ORCPT ); Sat, 2 Sep 2023 01:51:29 -0400 Received: from gnuweeb.org (gnuweeb.org [51.81.211.47]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 94A3F10FE for ; Fri, 1 Sep 2023 22:51:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gnuweeb.org; s=default; t=1693633881; bh=adKYv+UWCAtL6RnGzj9nIBJ/HQrhFBvKNcQpOXq1TGU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=lVAKBh4PEvXzamNP7IgFYjyUlSSIHtsv+itkbldEfvOGPycWYZcQ1nY4WLXOWcF9N UUj0TiGlFnWC5Mgwqmu+yvEfZMceFCEcjur4g2ujMNF0l6jIRTuJaX2BfJMxlkxhGB DU7P2Y4dYb2mHZaI3M3qUUIa6NfqzLuUWIIjWm859jM+YSR0vl1u9SFvCh2Bpy75WV LLBgbp57Dfqt4NXy8b/VoGzoaQmD2NMzGKK20jELwMbSOjCLrbx8ubkwhi7QkVhrns qpmfkSH7Jy8KUf0e91BjU/h3+cCSCgFwv3tW35X6pgwpXMhTO5IvQaRiAvcJp1pljH DFpp6ohZioF4g== Received: from localhost.localdomain (unknown [182.253.126.208]) by gnuweeb.org (Postfix) with ESMTPSA id 90ACB24B3B5; Sat, 2 Sep 2023 12:51:17 +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 v2 4/4] tools/nolibc: string: Remove the `_nolibc_memcpy_up()` function Date: Sat, 2 Sep 2023 12:50:45 +0700 Message-Id: <20230902055045.2138405-5-ammarfaizi2@gnuweeb.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230902055045.2138405-1-ammarfaizi2@gnuweeb.org> References: <20230902055045.2138405-1-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 --- 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