From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELunOhX3vhqIN1S8CYjpYeQuBW4gZdeXx2U2slfINZJfYqH62ZVFfnajm2TLgbKFKHrR9h6m ARC-Seal: i=1; a=rsa-sha256; t=1519981850; cv=none; d=google.com; s=arc-20160816; b=fKIf2r8WRLTzpqHLoofyUF6rwTtKloSVFKZgvHVFokyzdrpZH2YlaivUtrl7mepFO2 TTumrl0rjPF+EFEs2Tu3W1bf8dVuWtuucreXmi8anMXjWT1ifBSqIvwjUmVNVU4EOVEt 8t3rQ+0SLXJE6vEyX4BGZzhGqzyDE4IG4J1IIC/ig85kbZyUu8+D3/nQOhI6pvUP60yl lGlEci6llFMvQvOsDuaUDp4RqrHeJYVSPOv2wvh/mW+2kxCrXDBepxRm9Xj8fxrvWTzp 4DH9wp6eYwFavg5K8kI8gQyt2gLNacQANTKBCJmfIR3ScVsPPVFqv1ixXbNjzwPpAdlb Yzkg== 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:dkim-signature :arc-authentication-results; bh=QOGtQ77Id52+K+JjEVEiaNSdZ4g9u5jInb+GhtTO97g=; b=y0PL8kEcnI0V3ye/n6wHigD6JdFv3GxDHJ+CbpfKZdOHGAifG7OGgQs6v3iao9A97i +daDUFiSY9KGcP0vVZ/k5SLpVggUQEWwvHpxRbMPoIGBfbBeBcYTj7nIkdyN8lxab+5z ZWPMfFw+wL3PbjM89laBJpQ/DiK9i9bLg3qoHA98Hq+bBlNl755eUsohbCz+KDujVhce HWOOwlT1TsCwg+k67g56++tT2hIlBjv+DJ9KhmWtgvpgNpGc/ShTSwv4JchxTPDgs5Lr PlatU8Hvu2JlJ/bnaCENsJgiINlT1mEmAtZ69uypKeNxl9F4qHkuckGDAxR46bM1mw7O PnVg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass (test mode) header.i=@8bytes.org header.s=mail-1 header.b=OodDZoQk; spf=pass (google.com: domain of joro@8bytes.org designates 2a01:238:4383:600:38bc:a715:4b6d:a889 as permitted sender) smtp.mailfrom=joro@8bytes.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=8bytes.org Authentication-Results: mx.google.com; dkim=pass (test mode) header.i=@8bytes.org header.s=mail-1 header.b=OodDZoQk; spf=pass (google.com: domain of joro@8bytes.org designates 2a01:238:4383:600:38bc:a715:4b6d:a889 as permitted sender) smtp.mailfrom=joro@8bytes.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=8bytes.org Date: Fri, 2 Mar 2018 10:10:49 +0100 From: Joerg Roedel To: Linus Torvalds Cc: Brian Gerst , Joerg Roedel , Waiman Long , Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" , the arch/x86 maintainers , Linux Kernel Mailing List , Linux-MM , Andy Lutomirski , Dave Hansen , Josh Poimboeuf , Juergen Gross , Peter Zijlstra , Borislav Petkov , Jiri Kosina , Boris Ostrovsky , David Laight , Denys Vlasenko , Eduardo Valentin , Greg KH , Will Deacon , "Liguori, Anthony" , Daniel Gruss , Hugh Dickins , Kees Cook , Andrea Arcangeli , Waiman Long , Pavel Machek Subject: Re: [PATCH 12/31] x86/entry/32: Add PTI cr3 switch to non-NMI entry/exit points Message-ID: <20180302091049.GP16484@8bytes.org> References: <1518168340-9392-1-git-send-email-joro@8bytes.org> <1518168340-9392-13-git-send-email-joro@8bytes.org> <20180301133430.wda4qesqhxnww7d6@8bytes.org> <2ae8b01f-844b-b8b1-3198-5db70c3e083b@redhat.com> <20180301165019.kuynvb6fkcwdpxjx@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1591914904588119761?= X-GMAIL-MSGID: =?utf-8?q?1593816489024389496?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Thu, Mar 01, 2018 at 10:38:21AM -0800, Linus Torvalds wrote: > Note that debug traps can happen regardless of TF, Think kgdb etc. > Arguably kgdb users get what they deserve, but still.. I think root > can set kernel breakpoints too. But that seems to be broken right now at least wrt. to the espfix code where there is no handling for in the #DB handler. Can userspace really set arbitrary kernel breakpoints? Joerg