From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 696A8C43219 for ; Tue, 15 Nov 2022 19:43:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230137AbiKOTn4 (ORCPT ); Tue, 15 Nov 2022 14:43:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43366 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229602AbiKOTnz (ORCPT ); Tue, 15 Nov 2022 14:43:55 -0500 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9BE5D1B1E7; Tue, 15 Nov 2022 11:43:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=QnRFaJdTKibI758I9kj7cXS0kb/T4IK8Fmo0NNbrHpo=; b=RI9MhJbYpg6c3VLPNttnDQb2xQ OrqcxaY9Xgd61XCY8OUVnzvMF/dIS2ryHCuVfKlLsCv0/F5irZgoTtKnKMfiW7XrdluzBWQ0bWK3M 8SrwqVl13LxvaSNQ+Kfo1hC5vDLg8L9haDSBsPkyF54hbvnd5ZAiiYVkfnfK2qNaNK5J81UR+hn2V mR9bBwAcJqNH+gw+HVRkr3UrTGLD0HhCf+tYPu0d2HtvRzPQAJ2K4H0t+JEah8c/V5KUADskjYMI9 tz1fTfFrnjDh4e/c8g1IXN2v4W2zrA4nRI3kAWF0JE+xNithQ91lkY+8kJSqxR9+xzPa4f5PSKYj8 cCO/nCJw==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1ov1qD-0015RU-1o; Tue, 15 Nov 2022 19:43:29 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 3754E300F30; Tue, 15 Nov 2022 15:18:25 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 206542CB43B63; Tue, 15 Nov 2022 15:18:25 +0100 (CET) Date: Tue, 15 Nov 2022 15:18:25 +0100 From: Peter Zijlstra To: Rick Edgecombe Cc: x86@kernel.org, "H . Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H . J . Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Randy Dunlap , "Ravi V . Shankar" , Weijiang Yang , "Kirill A . Shutemov" , John Allen , kcc@google.com, eranian@google.com, rppt@kernel.org, jamorris@linux.microsoft.com, dethoma@microsoft.com, akpm@linux-foundation.org, Yu-cheng Yu Subject: Re: [PATCH v3 27/37] x86/shstk: Introduce routines modifying shstk Message-ID: References: <20221104223604.29615-1-rick.p.edgecombe@intel.com> <20221104223604.29615-28-rick.p.edgecombe@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221104223604.29615-28-rick.p.edgecombe@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org On Fri, Nov 04, 2022 at 03:35:54PM -0700, Rick Edgecombe wrote: > +#ifdef CONFIG_X86_USER_SHADOW_STACK > +static inline int write_user_shstk_64(u64 __user *addr, u64 val) > +{ > + asm_volatile_goto("1: wrussq %[val], (%[addr])\n" > + _ASM_EXTABLE(1b, %l[fail]) > + :: [addr] "r" (addr), [val] "r" (val) > + :: fail); > + return 0; > +fail: > + return -EFAULT; > +} > +#endif /* CONFIG_X86_USER_SHADOW_STACK */ Why isn't this modelled after put_user() ? Should you write a 64bit value even if the task receiving a signal is 32bit ?