From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pj1-x102e.google.com (mail-pj1-x102e.google.com [IPv6:2607:f8b0:4864:20::102e]) by sourceware.org (Postfix) with ESMTPS id CE33F3858D28 for ; Tue, 11 Jan 2022 02:15:54 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org CE33F3858D28 Received: by mail-pj1-x102e.google.com with SMTP id 59-20020a17090a09c100b001b34a13745eso2135697pjo.5 for ; Mon, 10 Jan 2022 18:15:54 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=LtgFVz5XlOX4a+TAexOooJd1/dVbkh9J/hd/FBsK2xA=; b=A0bl48NI+HGWtdWP2BbYLG9Yzk+s3nhYKNTqKFWxToqIUwiZwvFJ6KP+SUO4nXjin4 V7KXIed/VhtAg6yIkN35K4hgPM0v8pow0PF5ZwgKD1r5bppCaw5yKCSZomxjKY5idhDU LoD486qLAasCWXCPjvmgU5AiBTND53ft4mtF06Sh0L2oZodNlPY3c7rT1L5ELgnT7J6O K2Ao7w2HkcmLhoxI9d/R64kOJkEkuX4jfzzM+I2uLVle5Ogwo3hyGrcsGwA+vv2QKx8+ Pk7nATczm+HcqN9PmBogAFWwUO9NidpfomvCp5dj233RvGFOmsKGmD9jfYvIWQUshYGd yPng== X-Gm-Message-State: AOAM531VdYtBtwRAAesoTD2QIY5+zOOxEfEAPpv13N3kwRTmKbRphx3l 2mecJhwidkTi26NGmrbl9cNkn4306GBvnPTu0A325UNRRU8= X-Google-Smtp-Source: ABdhPJw3sI3WgAn2JSxUfYBTIE/M/fB6tuWUN5aFMF9L92TU/Nk7BVW602ao34gCnkP+9sIvjU2QyAjhc2wE1a+QumQ= X-Received: by 2002:a05:6a00:1311:b0:4ba:1288:67dc with SMTP id j17-20020a056a00131100b004ba128867dcmr2335299pfu.43.1641867353907; Mon, 10 Jan 2022 18:15:53 -0800 (PST) MIME-Version: 1.0 References: <20220109122946.2754917-1-goldstein.w.n@gmail.com> <20220110213540.1258344-1-goldstein.w.n@gmail.com> In-Reply-To: <20220110213540.1258344-1-goldstein.w.n@gmail.com> From: "H.J. Lu" Date: Mon, 10 Jan 2022 18:15:18 -0800 Message-ID: Subject: Re: [PATCH v3 1/7] x86: Fix __wcsncmp_avx2 in strcmp-avx2.S [BZ# 28755] To: Noah Goldstein Cc: GNU C Library Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-3028.2 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 11 Jan 2022 02:15:56 -0000 On Mon, Jan 10, 2022 at 1:36 PM Noah Goldstein via Libc-alpha wrote: > > Fixes [BZ# 28755] for wcsncmp by redirecting length >= 2^56 to > __wcscmp_avx2. For x86_64 this covers the entire address range so any > length larger could not possibly be used to bound `s1` or `s2`. > > test-strcmp, test-strncmp, test-wcscmp, and test-wcsncmp all pass. > > Signed-off-by: Noah Goldstein > --- > sysdeps/x86_64/multiarch/strcmp-avx2.S | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/sysdeps/x86_64/multiarch/strcmp-avx2.S b/sysdeps/x86_64/multiarch/strcmp-avx2.S > index a45f9d2749..9c73b5899d 100644 > --- a/sysdeps/x86_64/multiarch/strcmp-avx2.S > +++ b/sysdeps/x86_64/multiarch/strcmp-avx2.S > @@ -87,6 +87,16 @@ ENTRY (STRCMP) > je L(char0) > jb L(zero) > # ifdef USE_AS_WCSCMP > +# ifndef __ILP32__ > + movq %rdx, %rcx > + /* Check if length could overflow when multiplied by > + sizeof(wchar_t). Checking top 8 bits will cover all potential > + overflow cases as well as redirect cases where its impossible to > + length to bound a valid memory region. In these cases just use > + 'wcscmp'. */ > + shrq $56, %rcx > + jnz __wcscmp_avx2 > +# endif > /* Convert units: from wide to byte char. */ > shl $2, %RDX_LP > # endif > -- > 2.25.1 > LGTM. Reviewed-by: H.J. Lu Thanks. -- H.J.