From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl1-x629.google.com (mail-pl1-x629.google.com [IPv6:2607:f8b0:4864:20::629]) by sourceware.org (Postfix) with ESMTPS id 44A853858424 for ; Mon, 10 Jan 2022 00:35:31 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 44A853858424 Received: by mail-pl1-x629.google.com with SMTP id t18so1054522plg.9 for ; Sun, 09 Jan 2022 16:35:31 -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=fFl8fHWAV7qSycUeR0gPn7leIjOC7mYlAWiZMkvNR18=; b=abzpW2lgvfqsY3mSsuUiCCCJKTFDSMuKudniz2S+lG5Hbeq3Lp15xnY+qex19eKcvp vhzy6l8U4sj8OCgPBBvL4+D0aPoyJkPQhRXcXAZuZF68JF9cuuBFqqTdRgiZKKwqM3Pn O9T2RaT/MkaZlRjeJV7hvWe9eYBdb2vf27dLIbE7Incyibr7bFvy65LNzw0g991njvpn OSIryTWoNSk+yoPErDXM6NObme+jZMvfk2DOSbDe7OwVN2ihqGZR3qmdEVS51vhFBz1u aweXdBXOYCorWWsaSNlZTHKvBlTmVkgCDDyKECmSH9ORR0atOdwBfenhTnvquxqXecKD 6Zyw== X-Gm-Message-State: AOAM530eNGc6UjrWfuSKCGNU/QUzAWa44QIeV6tRQqImPlQkfKeS0reZ pAke8dGz0f5/aDU4qaaPVfZrpUPcnfCcMtHLXeYA7A6h9Xk= X-Google-Smtp-Source: ABdhPJyqyz/RIENfxquS/GJ3eJi50CSqQCnZDQWdnBV392nGXh56wElgkzb4pEeOG4BnV4uzFI5KneOGOJtLLYSzkZg= X-Received: by 2002:a17:90a:b798:: with SMTP id m24mr14124391pjr.143.1641774930352; Sun, 09 Jan 2022 16:35:30 -0800 (PST) MIME-Version: 1.0 References: <20220109122946.2754917-1-goldstein.w.n@gmail.com> <20220110002746.3653516-1-goldstein.w.n@gmail.com> In-Reply-To: <20220110002746.3653516-1-goldstein.w.n@gmail.com> From: "H.J. Lu" Date: Sun, 9 Jan 2022 16:34:54 -0800 Message-ID: Subject: Re: [PATCH v2 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=-3028.1 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: Mon, 10 Jan 2022 00:35:32 -0000 On Sun, Jan 9, 2022 at 4:28 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.