From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 44223C433B4 for ; Wed, 12 May 2021 13:34:51 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9DBAB613DA for ; Wed, 12 May 2021 13:34:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9DBAB613DA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=1kJaRfKhCap+CQD7vyQNqrrZSaVdPuoPQ2Ohe3Sf1RY=; b=Lp7ssHA6ksL7IOHqlikHt9Bm7 PhLL/hfgUj58bgj+lvs9QtvvutPtpdvzscu8jCeb8scAi7WmCoXk5nV3/XOESwY+sQiofi89iygim pC3EUixmzWtr/gESDNjn3NgGUxITSmesZueFicFdWsTKGA0oZYE2DoH00BM4WWXcAqOwOLJI10OMr ReKnwudraLoNUmiXqgnK5URyosnZ20PZjAbCZCturpD5kfJdvTMZnA20YYavFZ2zMowWHmvj1px4u SBrGWaaImP2KKQ9isnawhhU1z8aUB0X5cEBVbE7FB27z7TV2AoXlTMIyrVBYbO11cSh3C9c/TUjfy Rh1X4ZXpA==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lgoyI-002tyZ-9g; Wed, 12 May 2021 13:32:19 +0000 Received: from bombadil.infradead.org ([2607:7c80:54:e::133]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lgout-002tWL-47 for linux-arm-kernel@desiato.infradead.org; Wed, 12 May 2021 13:28:47 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=Tw2Anl7+PPbtriNSq5S0Z5oY82n6zmJWOPvOIJKuIFE=; b=OA3E1issAxXeDYZT10wFp9Ycy1 Q2Hos9uz+fwZJQXV63t/Hy7KnwvB9MhI3WQD/0n+auP+qVEliWgCepJoIy4vVFEm3iXZyVf95UJKj 5pi9UH5R7jkLBFFPGszNJSgzpSkf/upL43VMXtkoBM19mdUxvqm47GxVb6GoXM40hGUIWOjp3Aqj7 nw9Gsi7byGgVvXhEiTqvGT07njsBkooFhN5+FXDDpNMhmxkZrHTuy8wVTDfSVL1QFJ3nUlqw4hN3Z PWr0YRG/zhoU2Q8HFjrB9phzxLkdb1j5Od3uQuESsXI21CpDlZYvJDDgop8ZlIPX8T34a9XdZ5wnP ENVP12bg==; Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lgouo-00AP3O-QC for linux-arm-kernel@lists.infradead.org; Wed, 12 May 2021 13:28:45 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 188BE6D; Wed, 12 May 2021 06:28:37 -0700 (PDT) Received: from C02TD0UTHF1T.local (unknown [10.57.72.67]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 66CE33F718; Wed, 12 May 2021 06:28:35 -0700 (PDT) Date: Wed, 12 May 2021 14:28:32 +0100 From: Mark Rutland To: Robin Murphy Cc: will@kernel.org, catalin.marinas@arm.com, linux-arm-kernel@lists.infradead.org, yangyingliang@huawei.com, shenkai8@huawei.com Subject: Re: [PATCH 1/8] arm64: Import latest version of Cortex Strings' memcmp Message-ID: <20210512132832.GB93815@C02TD0UTHF1T.local> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210512_062842_973938_F4B4F053 X-CRM114-Status: GOOD ( 42.65 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Robin, On Tue, May 11, 2021 at 05:12:31PM +0100, Robin Murphy wrote: > From: Sam Tebbs > > Import the latest version of the former Cortex Strings - now > Arm Optimized Routines - memcmp function based on the upstream > code of string/aarch64/memcmp.S at commit e823e3a from > https://github.com/ARM-software/optimized-routines What's the licensing/copyright situation here? Because below... > > Signed-off-by: Sam Tebbs > [ rm: update attribution and commit message ] > Signed-off-by: Robin Murphy > --- > arch/arm64/lib/memcmp.S | 330 ++++++++++++++-------------------------- > 1 file changed, 111 insertions(+), 219 deletions(-) > > diff --git a/arch/arm64/lib/memcmp.S b/arch/arm64/lib/memcmp.S > index c0671e793ea9..498f0d9941d9 100644 > --- a/arch/arm64/lib/memcmp.S > +++ b/arch/arm64/lib/memcmp.S > @@ -1,247 +1,139 @@ > /* SPDX-License-Identifier: GPL-2.0-only */ ... this says GPL-2.0-only .... > /* > - * Copyright (C) 2013 ARM Ltd. > - * Copyright (C) 2013 Linaro. > + * Copyright (c) 2013-2020, Arm Limited. > * > - * This code is based on glibc cortex strings work originally authored by Linaro > - * be found @ > - * > - * http://bazaar.launchpad.net/~linaro-toolchain-dev/cortex-strings/trunk/ > - * files/head:/src/aarch64/ > + * Adapted from the original at: > + * https://github.com/ARM-software/optimized-routines/blob/master/string/aarch64/memcmp.S > */ ... but this referenced file says "SPDX-License-Identifier: MIT", and I don't know when this relicensing is legitimate. Thanks, Mark. > > #include > #include > > -/* > -* compare memory areas(when two memory areas' offset are different, > -* alignment handled by the hardware) > -* > -* Parameters: > -* x0 - const memory area 1 pointer > -* x1 - const memory area 2 pointer > -* x2 - the maximal compare byte length > -* Returns: > -* x0 - a compare result, maybe less than, equal to, or greater than ZERO > -*/ > +/* Assumptions: > + * > + * ARMv8-a, AArch64, unaligned accesses. > + */ > + > +#define L(label) .L ## label > > /* Parameters and result. */ > -src1 .req x0 > -src2 .req x1 > -limit .req x2 > -result .req x0 > +#define src1 x0 > +#define src2 x1 > +#define limit x2 > +#define result w0 > > /* Internal variables. */ > -data1 .req x3 > -data1w .req w3 > -data2 .req x4 > -data2w .req w4 > -has_nul .req x5 > -diff .req x6 > -endloop .req x7 > -tmp1 .req x8 > -tmp2 .req x9 > -tmp3 .req x10 > -pos .req x11 > -limit_wd .req x12 > -mask .req x13 > +#define data1 x3 > +#define data1w w3 > +#define data1h x4 > +#define data2 x5 > +#define data2w w5 > +#define data2h x6 > +#define tmp1 x7 > +#define tmp2 x8 > > SYM_FUNC_START_WEAK_PI(memcmp) > - cbz limit, .Lret0 > - eor tmp1, src1, src2 > - tst tmp1, #7 > - b.ne .Lmisaligned8 > - ands tmp1, src1, #7 > - b.ne .Lmutual_align > - sub limit_wd, limit, #1 /* limit != 0, so no underflow. */ > - lsr limit_wd, limit_wd, #3 /* Convert to Dwords. */ > - /* > - * The input source addresses are at alignment boundary. > - * Directly compare eight bytes each time. > - */ > -.Lloop_aligned: > - ldr data1, [src1], #8 > - ldr data2, [src2], #8 > -.Lstart_realigned: > - subs limit_wd, limit_wd, #1 > - eor diff, data1, data2 /* Non-zero if differences found. */ > - csinv endloop, diff, xzr, cs /* Last Dword or differences. */ > - cbz endloop, .Lloop_aligned > + subs limit, limit, 8 > + b.lo L(less8) > > - /* Not reached the limit, must have found a diff. */ > - tbz limit_wd, #63, .Lnot_limit > + ldr data1, [src1], 8 > + ldr data2, [src2], 8 > + cmp data1, data2 > + b.ne L(return) > > - /* Limit % 8 == 0 => the diff is in the last 8 bytes. */ > - ands limit, limit, #7 > - b.eq .Lnot_limit > - /* > - * The remained bytes less than 8. It is needed to extract valid data > - * from last eight bytes of the intended memory range. > - */ > - lsl limit, limit, #3 /* bytes-> bits. */ > - mov mask, #~0 > -CPU_BE( lsr mask, mask, limit ) > -CPU_LE( lsl mask, mask, limit ) > - bic data1, data1, mask > - bic data2, data2, mask > + subs limit, limit, 8 > + b.gt L(more16) > > - orr diff, diff, mask > - b .Lnot_limit > + ldr data1, [src1, limit] > + ldr data2, [src2, limit] > + b L(return) > > -.Lmutual_align: > - /* > - * Sources are mutually aligned, but are not currently at an > - * alignment boundary. Round down the addresses and then mask off > - * the bytes that precede the start point. > - */ > - bic src1, src1, #7 > - bic src2, src2, #7 > - ldr data1, [src1], #8 > - ldr data2, [src2], #8 > - /* > - * We can not add limit with alignment offset(tmp1) here. Since the > - * addition probably make the limit overflown. > - */ > - sub limit_wd, limit, #1/*limit != 0, so no underflow.*/ > - and tmp3, limit_wd, #7 > - lsr limit_wd, limit_wd, #3 > - add tmp3, tmp3, tmp1 > - add limit_wd, limit_wd, tmp3, lsr #3 > - add limit, limit, tmp1/* Adjust the limit for the extra. */ > +L(more16): > + ldr data1, [src1], 8 > + ldr data2, [src2], 8 > + cmp data1, data2 > + bne L(return) > > - lsl tmp1, tmp1, #3/* Bytes beyond alignment -> bits.*/ > - neg tmp1, tmp1/* Bits to alignment -64. */ > - mov tmp2, #~0 > - /*mask off the non-intended bytes before the start address.*/ > -CPU_BE( lsl tmp2, tmp2, tmp1 )/*Big-endian.Early bytes are at MSB*/ > - /* Little-endian. Early bytes are at LSB. */ > -CPU_LE( lsr tmp2, tmp2, tmp1 ) > + /* Jump directly to comparing the last 16 bytes for 32 byte (or less) > + strings. */ > + subs limit, limit, 16 > + b.ls L(last_bytes) > > - orr data1, data1, tmp2 > - orr data2, data2, tmp2 > - b .Lstart_realigned > + /* We overlap loads between 0-32 bytes at either side of SRC1 when we > + try to align, so limit it only to strings larger than 128 bytes. */ > + cmp limit, 96 > + b.ls L(loop16) > > - /*src1 and src2 have different alignment offset.*/ > -.Lmisaligned8: > - cmp limit, #8 > - b.lo .Ltiny8proc /*limit < 8: compare byte by byte*/ > + /* Align src1 and adjust src2 with bytes not yet done. */ > + and tmp1, src1, 15 > + add limit, limit, tmp1 > + sub src1, src1, tmp1 > + sub src2, src2, tmp1 > > - and tmp1, src1, #7 > - neg tmp1, tmp1 > - add tmp1, tmp1, #8/*valid length in the first 8 bytes of src1*/ > - and tmp2, src2, #7 > - neg tmp2, tmp2 > - add tmp2, tmp2, #8/*valid length in the first 8 bytes of src2*/ > - subs tmp3, tmp1, tmp2 > - csel pos, tmp1, tmp2, hi /*Choose the maximum.*/ > + /* Loop performing 16 bytes per iteration using aligned src1. > + Limit is pre-decremented by 16 and must be larger than zero. > + Exit if <= 16 bytes left to do or if the data is not equal. */ > + .p2align 4 > +L(loop16): > + ldp data1, data1h, [src1], 16 > + ldp data2, data2h, [src2], 16 > + subs limit, limit, 16 > + ccmp data1, data2, 0, hi > + ccmp data1h, data2h, 0, eq > + b.eq L(loop16) > > - sub limit, limit, pos > - /*compare the proceeding bytes in the first 8 byte segment.*/ > -.Ltinycmp: > - ldrb data1w, [src1], #1 > - ldrb data2w, [src2], #1 > - subs pos, pos, #1 > - ccmp data1w, data2w, #0, ne /* NZCV = 0b0000. */ > - b.eq .Ltinycmp > - cbnz pos, 1f /*diff occurred before the last byte.*/ > + cmp data1, data2 > + bne L(return) > + mov data1, data1h > + mov data2, data2h > + cmp data1, data2 > + bne L(return) > + > + /* Compare last 1-16 bytes using unaligned access. */ > +L(last_bytes): > + add src1, src1, limit > + add src2, src2, limit > + ldp data1, data1h, [src1] > + ldp data2, data2h, [src2] > + cmp data1, data2 > + bne L(return) > + mov data1, data1h > + mov data2, data2h > + cmp data1, data2 > + > + /* Compare data bytes and set return value to 0, -1 or 1. */ > +L(return): > +#ifndef __AARCH64EB__ > + rev data1, data1 > + rev data2, data2 > +#endif > + cmp data1, data2 > +L(ret_eq): > + cset result, ne > + cneg result, result, lo > + ret > + > + .p2align 4 > + /* Compare up to 8 bytes. Limit is [-8..-1]. */ > +L(less8): > + adds limit, limit, 4 > + b.lo L(less4) > + ldr data1w, [src1], 4 > + ldr data2w, [src2], 4 > cmp data1w, data2w > - b.eq .Lstart_align > -1: > - sub result, data1, data2 > + b.ne L(return) > + sub limit, limit, 4 > +L(less4): > + adds limit, limit, 4 > + beq L(ret_eq) > +L(byte_loop): > + ldrb data1w, [src1], 1 > + ldrb data2w, [src2], 1 > + subs limit, limit, 1 > + ccmp data1w, data2w, 0, ne /* NZCV = 0b0000. */ > + b.eq L(byte_loop) > + sub result, data1w, data2w > ret > > -.Lstart_align: > - lsr limit_wd, limit, #3 > - cbz limit_wd, .Lremain8 > - > - ands xzr, src1, #7 > - b.eq .Lrecal_offset > - /*process more leading bytes to make src1 aligned...*/ > - add src1, src1, tmp3 /*backwards src1 to alignment boundary*/ > - add src2, src2, tmp3 > - sub limit, limit, tmp3 > - lsr limit_wd, limit, #3 > - cbz limit_wd, .Lremain8 > - /*load 8 bytes from aligned SRC1..*/ > - ldr data1, [src1], #8 > - ldr data2, [src2], #8 > - > - subs limit_wd, limit_wd, #1 > - eor diff, data1, data2 /*Non-zero if differences found.*/ > - csinv endloop, diff, xzr, ne > - cbnz endloop, .Lunequal_proc > - /*How far is the current SRC2 from the alignment boundary...*/ > - and tmp3, tmp3, #7 > - > -.Lrecal_offset:/*src1 is aligned now..*/ > - neg pos, tmp3 > -.Lloopcmp_proc: > - /* > - * Divide the eight bytes into two parts. First,backwards the src2 > - * to an alignment boundary,load eight bytes and compare from > - * the SRC2 alignment boundary. If all 8 bytes are equal,then start > - * the second part's comparison. Otherwise finish the comparison. > - * This special handle can garantee all the accesses are in the > - * thread/task space in avoid to overrange access. > - */ > - ldr data1, [src1,pos] > - ldr data2, [src2,pos] > - eor diff, data1, data2 /* Non-zero if differences found. */ > - cbnz diff, .Lnot_limit > - > - /*The second part process*/ > - ldr data1, [src1], #8 > - ldr data2, [src2], #8 > - eor diff, data1, data2 /* Non-zero if differences found. */ > - subs limit_wd, limit_wd, #1 > - csinv endloop, diff, xzr, ne/*if limit_wd is 0,will finish the cmp*/ > - cbz endloop, .Lloopcmp_proc > -.Lunequal_proc: > - cbz diff, .Lremain8 > - > -/* There is difference occurred in the latest comparison. */ > -.Lnot_limit: > -/* > -* For little endian,reverse the low significant equal bits into MSB,then > -* following CLZ can find how many equal bits exist. > -*/ > -CPU_LE( rev diff, diff ) > -CPU_LE( rev data1, data1 ) > -CPU_LE( rev data2, data2 ) > - > - /* > - * The MS-non-zero bit of DIFF marks either the first bit > - * that is different, or the end of the significant data. > - * Shifting left now will bring the critical information into the > - * top bits. > - */ > - clz pos, diff > - lsl data1, data1, pos > - lsl data2, data2, pos > - /* > - * We need to zero-extend (char is unsigned) the value and then > - * perform a signed subtraction. > - */ > - lsr data1, data1, #56 > - sub result, data1, data2, lsr #56 > - ret > - > -.Lremain8: > - /* Limit % 8 == 0 =>. all data are equal.*/ > - ands limit, limit, #7 > - b.eq .Lret0 > - > -.Ltiny8proc: > - ldrb data1w, [src1], #1 > - ldrb data2w, [src2], #1 > - subs limit, limit, #1 > - > - ccmp data1w, data2w, #0, ne /* NZCV = 0b0000. */ > - b.eq .Ltiny8proc > - sub result, data1, data2 > - ret > -.Lret0: > - mov result, #0 > - ret > SYM_FUNC_END_PI(memcmp) > EXPORT_SYMBOL_NOKASAN(memcmp) > -- > 2.21.0.dirty > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel