From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pj1-x102f.google.com (mail-pj1-x102f.google.com [IPv6:2607:f8b0:4864:20::102f]) by sourceware.org (Postfix) with ESMTPS id 3753F3858C78; Thu, 27 Jan 2022 04:30:19 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 3753F3858C78 Received: by mail-pj1-x102f.google.com with SMTP id z10-20020a17090acb0a00b001b520826011so6322043pjt.5; Wed, 26 Jan 2022 20:30:19 -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=FE2l5sHk4sR4oQt4E4ysSu9IGnJxFv5rAKZMPJW7WHI=; b=MXcDu0ffweVDUln1G1uWpiNBoBTOAlusvS3rbZh+gKHN0gCvEYAS+oT9bbXMRgzIll 6W5nvJnJZLpL1oeK/N+oxOO1OVeiypka4rFIZDrjNRTXYh7ZuKEaliUiqhllKMqNY4cD yYOuQVd3HaC1aj2m4vcV+Hz2oxgSyvsv8jOKnXGum+VB0FkLj8QSH9j/M0Fs5xDtpRJn XbNYjvsVC2D1wztMVv9dme7VEvF569Siwl6qA4ynj+gletIuCsQjmzyELkC7LhgPL7IA n05iG0kRlSOAQeSmXo5GmCETL16qCgKl4VvtPATnqRXCKJ3eoLSZ1ksv/zTOx8IpgqB9 HmTQ== X-Gm-Message-State: AOAM5335FGXHe1my1m4f+5klv8fPACNAqF7W+zYuz6PriDkIeedzmd7z TNNiHG9BTSotMG5C9x8e5zfrUPbiap/lNQTU50931eh5h2g= X-Google-Smtp-Source: ABdhPJwgVQmVveSadPbLtebCAjlXqqlkNQnu49TMvolsQtsSA19A5imAa6z7+ULlVRGEuxL5rqJ6N5dv99GZ5dvCZ1I= X-Received: by 2002:a17:90a:1950:: with SMTP id 16mr12290761pjh.28.1643257818280; Wed, 26 Jan 2022 20:30:18 -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: From: "H.J. Lu" Date: Wed, 26 Jan 2022 20:29:41 -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 , Libc-stable Mailing List Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-3027.4 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-stable@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-stable mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 27 Jan 2022 04:30:21 -0000 On Wed, Jan 26, 2022 at 2:05 PM H.J. Lu wrote: > > On Mon, Jan 10, 2022 at 6:15 PM H.J. Lu wrote: > > > > 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. > > I am backporting this to 2.34 branch. > I am backporting this to 2.33 branch. -- H.J.