From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx48Atgvy+ktcvVWwdhVXUpyPgPF7yuc2X1sOIsMpYUKpuE2ZK4CTQoPkbwEfy0ysa2RNYHfc ARC-Seal: i=1; a=rsa-sha256; t=1523871630; cv=none; d=google.com; s=arc-20160816; b=zHEf6dyC3QyvN5Uhm+mKxbGDyNvLRiegvNkyENnhVzD7awFYV7R0WCR+I47SyYQIwZ VJCVXIhT+Ll8GYHfQcIXtWAiCNNDDUR0TVsuMxCv0Tuce5anAX8Vv5VumUzVQbXYkK0d GqVbQFbaH3+EGyDQgCqheXSO0jYF5LAYWX31Ojqm39/t/onhYalq6Yeox+GFRqpkZmZP +RKsiIEBp+LiDwI2VtHsDkjbuFj9EJoP1Du8qzi6Sjg8KsOsa5Kpa87kzZprSY+xlfGV 8RjKHFPnGNI6fF3Ek6UX3y31wbFu6VjyCcT/4xGwLAIkN9q1JQgNPg2u9dvkAG9jS/Jc ebJQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:sender:dkim-signature :delivered-to:list-id:list-subscribe:list-unsubscribe:list-help :list-post:precedence:mailing-list:arc-authentication-results; bh=tHLVbh7OfgkyX/fwEdPPeyWW9h8PuXa79SBPQId2mkY=; b=MXzQPoh2kSD3wdnjJ2wqZ3IQ4rcRdQLNY9QBojceTg572ukcNOtkVK6LFnM7AnT4Ij Gq6VSiXsC6uBece4j81N+T0tgGzMtDiDxYAUBQ3ic/7eZ9Or/6SvcEvroc3yqHUIR66X SqXD8KZUP3dE/CzDOF80Z2elUBzNPq5KiPdBTt/GS/ANY4PQIr/IDcfTwulEjqEhZKBS E19yce73Fow3nWLU8DG5y28GFFWdUIdxncaoamfR8qNRgVgKnH7+KoGcxd7WpSskT1qR ssOqHBRtZzFzuhiLjo8u60hSD3H4yvSgiSd2QzrXRc0y2qgW/YwSSV+Yy1RedJ4Fd+An QsJA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=Ws+RLAXO; spf=pass (google.com: domain of kernel-hardening-return-13008-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-13008-gregkh=linuxfoundation.org@lists.openwall.com Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=Ws+RLAXO; spf=pass (google.com: domain of kernel-hardening-return-13008-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-13008-gregkh=linuxfoundation.org@lists.openwall.com Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm List-Post: List-Help: List-Unsubscribe: List-Subscribe: Sender: Ingo Molnar Date: Mon, 16 Apr 2018 11:40:07 +0200 From: Ingo Molnar To: Laura Abbott Cc: Boris Ostrovsky , Juergen Gross , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com Subject: Re: [PATCH] x86/xen: Remove use of VLAs Message-ID: <20180416094007.diuobump2qxraybx@gmail.com> References: <20180413221146.28476-1-labbott@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180413221146.28476-1-labbott@redhat.com> User-Agent: NeoMutt/20170609 (1.8.3) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1597670729617678421?= X-GMAIL-MSGID: =?utf-8?q?1597895219048226986?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: * Laura Abbott wrote: > There's an ongoing effort to remove VLAs[1] from the kernel to eventually > turn on -Wvla. The few VLAs in use have an upper bound based on a size > of 64K. This doesn't produce an excessively large stack so just switch > the upper bound. > > [1] https://lkml.org/lkml/2018/3/7/621 > > Signed-off-by: Laura Abbott > --- > arch/x86/xen/enlighten_pv.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c > index c36d23aa6c35..d96a5a535cbb 100644 > --- a/arch/x86/xen/enlighten_pv.c > +++ b/arch/x86/xen/enlighten_pv.c > @@ -421,8 +421,7 @@ static void xen_load_gdt(const struct desc_ptr *dtr) > { > unsigned long va = dtr->address; > unsigned int size = dtr->size + 1; > - unsigned pages = DIV_ROUND_UP(size, PAGE_SIZE); > - unsigned long frames[pages]; > + unsigned long frames[DIV_ROUND_UP(SZ_64K, PAGE_SIZE)]; > int f; > > /* > @@ -470,8 +469,7 @@ static void __init xen_load_gdt_boot(const struct desc_ptr *dtr) > { > unsigned long va = dtr->address; > unsigned int size = dtr->size + 1; > - unsigned pages = DIV_ROUND_UP(size, PAGE_SIZE); > - unsigned long frames[pages]; > + unsigned long frames[DIV_ROUND_UP(SZ_64K, PAGE_SIZE)]; > int f; Reviewed-by: Ingo Molnar Thanks, Ingo