From owner-svn-src-all@freebsd.org Thu Jan 14 16:23:09 2016 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 4BC48A82778; Thu, 14 Jan 2016 16:23:09 +0000 (UTC) (envelope-from imp@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id F1B251E5F; Thu, 14 Jan 2016 16:23:08 +0000 (UTC) (envelope-from imp@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id u0EGN76d063432; Thu, 14 Jan 2016 16:23:07 GMT (envelope-from imp@FreeBSD.org) Received: (from imp@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id u0EGN7me063431; Thu, 14 Jan 2016 16:23:07 GMT (envelope-from imp@FreeBSD.org) Message-Id: <201601141623.u0EGN7me063431@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: imp set sender to imp@FreeBSD.org using -f From: Warner Losh Date: Thu, 14 Jan 2016 16:23:07 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r294011 - head/share/man/man4 X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 14 Jan 2016 16:23:09 -0000 Author: imp Date: Thu Jan 14 16:23:07 2016 New Revision: 294011 URL: https://svnweb.freebsd.org/changeset/base/294011 Log: Document how to enter the debugger here. I'm sure there's some better canonical place, and the nit-pickers are welcome to move this information there with a cross reference. Differential Review: https://reviews.freebsd.org/D4860 Modified: head/share/man/man4/ddb.4 Modified: head/share/man/man4/ddb.4 ============================================================================== --- head/share/man/man4/ddb.4 Thu Jan 14 16:21:58 2016 (r294010) +++ head/share/man/man4/ddb.4 Thu Jan 14 16:23:07 2016 (r294011) @@ -1435,6 +1435,47 @@ The NMI allows one to break into the deb diagnose problems. Other bus' bridge chipsets may be able to generate NMI using bus specific methods. +There are many PCI and PCIe add-in cards which can generate NMI for +debugging. +Modern systems typically use IMPI to generate signals to enter the +debugger. +The +.Dv devel/ipmitool +port can be used to send the +.Cd chassis power diag +command which delivers an NMI to the processor. +.Pp +For serial consoles, you can break to the debugger by sending a BREAK +condition on the serial line if +.Cd options BREAK_TO_DEBUGGER +is specified in the kernel. +Most terminal emulation programs can send a break sequence with a +special key sequence or via a menu item. +However, in some setups, sending the break can be difficult to arrange +or happens spuriously, so if the kernel contains +.Cd options ALT_BREAK_TO_DEBUGGER +then the sequence of CR TILDE CTRL-B enters the debugger; +CR TILDE CTRL-P causes a panic instead of entering the +debugger; and +CR TILDE CTRL-R causes an immediate reboot. +In all the above sequences, CR is a Carriage Return and is usually +sent by hitting the Enter or Return key. +TILDE is the ASCII tilde character (~). +CTRL-x is Control x created by hitting the control key and then x +and then releasing both. +.Pp +The break to debugger behavior may also be enabled by setting the +.Xr sysctl 8 +.Dv debug.kdb.break_to_debugger +to 1. +The alt break to debugger behavior may also be enabled by setting the +.Xr sysctl 8 +.Dv debug.kdb.alt_break_to_debugger +to 1. +The debugger may be entered by setting the +.Xr sysctl 8 +.Dv debug.kdb.enter +to 1. .Sh FILES Header files mentioned in this manual page can be found below .Pa /usr/include