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[2607:7c80:54:e::133]) by mx.google.com with ESMTPS id o12si7374378plg.221.2019.03.22.06.21.40 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 22 Mar 2019 06:21:40 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of batv+727712e9dcf37bb32c64+5689+infradead.org+hch@bombadil.srs.infradead.org designates 2607:7c80:54:e::133 as permitted sender) client-ip=2607:7c80:54:e::133; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20170209 header.b=Zbt4AiAW; spf=pass (google.com: best guess record for domain of batv+727712e9dcf37bb32c64+5689+infradead.org+hch@bombadil.srs.infradead.org designates 2607:7c80:54:e::133 as permitted sender) smtp.mailfrom=BATV+727712e9dcf37bb32c64+5689+infradead.org+hch@bombadil.srs.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Transfer-Encoding :Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=hw3ZtZSh4y78LcwFC7knlBZdOdzIfUNtqXkI2P++IvI=; b=Zbt4AiAWGBY6okvEekZtK6TS4F PTLe64W03umLD5nMSHvoCMhFEc4lCxttGX4EneARFbw7Wk07uvTnz/Ir8Hl1nAuKuj3nWtYcwKHfG 4lnt+VewjSCFLnWQf0H6NwJw0adquIeo05Oj6qlq6AOFapqexQfI8VP518uRb7Pi5IqICBdl92ARY tDAnHXgUGavzntghHV+Bay6zLlMg1KYzVuN20T34X59Oc8MmgfVAJgxJQwa0GUnqoz9YSMbg9h/Ow IH3z+678WV11fgVbeRfilpWZX1p31/flKDOsK2UqdbN/QAWsLrzzQAqzjhUf2yTf9GSLzrZZqdNLG r47bHwFQ==; Received: from hch by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1h7K6x-00047T-Fh; Fri, 22 Mar 2019 13:21:27 +0000 Date: Fri, 22 Mar 2019 06:21:27 -0700 From: Christoph Hellwig To: Alexandre Ghiti Cc: Christoph Hellwig , Russell King , Catalin Marinas , Will Deacon , Ralf Baechle , Paul Burton , James Hogan , Palmer Dabbelt , Albert Ou , Alexander Viro , Luis Chamberlain , Kees Cook , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 1/4] arm64, mm: Move generic mmap layout functions to mm Message-ID: <20190322132127.GA18602@infradead.org> References: <20190322074225.22282-1-alex@ghiti.fr> <20190322074225.22282-2-alex@ghiti.fr> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20190322074225.22282-2-alex@ghiti.fr> User-Agent: Mutt/1.9.2 (2017-12-15) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: > It then introduces a new define ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT > that can be defined by other architectures to benefit from those functions. Can you make this a Kconfig option defined in arch/Kconfig or mm/Kconfig and selected by the architectures? > -#ifndef STACK_RND_MASK > -#define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12)) /* 8MB of VA */ > -#endif > - > -static unsigned long randomize_stack_top(unsigned long stack_top) > -{ > - unsigned long random_variable = 0; > - > - if (current->flags & PF_RANDOMIZE) { > - random_variable = get_random_long(); > - random_variable &= STACK_RND_MASK; > - random_variable <<= PAGE_SHIFT; > - } > -#ifdef CONFIG_STACK_GROWSUP > - return PAGE_ALIGN(stack_top) + random_variable; > -#else > - return PAGE_ALIGN(stack_top) - random_variable; > -#endif > -} > - Maybe the move of this function can be split into another prep patch, as it is only very lightly related? > +#if defined(HAVE_ARCH_PICK_MMAP_LAYOUT) || \ > + defined(ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT) Not sure if it is wrіtten down somehwere or just convention, but I general see cpp defined statements aligned with spaces to the one on the previous line. Except for these nitpicks this looks very nice to me, thanks for doing this work!