From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bruno Vidal Date: Tue, 13 May 2003 07:38:05 +0000 Subject: Re: [Linux-ia64] Dump driver module Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org David Mosberger wrote: >>>>>>On Tue, 13 May 2003 09:02:48 +0200, Bruno Vidal said: >>>>> > > Bruno> I've already wrote a dump modules driver for linux-parisc. > Bruno> This module goal is to create a memory image on a swap area, and > Bruno> at reboot time to save it to disk with all kernel modules, in > Bruno> order to analyze it after by "support" people with tools like > Bruno> gdb/p4. The problem while dumping is that the dump modules > Bruno> cannot trust anymore the system, so dumping means: no interruption, > Bruno> no disk driver, no buffer, nothing. The solution is to use low level > Bruno> call. For parisc I use the IODC calls, for ia64 I think I'll > Bruno> use the EFI calls. My questions: > Bruno> -do you think it is a "good" and realistic solution. > Bruno> -because I think "yes", does exist somewhere an example of > Bruno> reading/writing with EFI call on disk using BLOCK IO. I've already > Bruno> looked in elilo, but it seems that it use FS access. > > Once the kernel is booted, you can access only the EFI runtime > services (see struct efi in include/linux/efi.h). I'm afraid there is > no support for writing disk blocks. Given this limitation, I suspect > you'd have to include your own (simple) disk driver(s). > > --david > > . > I've already seen this EFI runtime service, and there is nearly nothing in it (nothing usefull for IO), so what I can understand is I have to write (rewrite) a driver for each kind of scsi/ide interface....it is not really realistic :-( There is no other way to access EFI or firmware ? Or reset back EFI to have access to BLOCK IO interface ? For example in parisc, the first thing to do, is to a do a PDC_IO_RESET, it freeze the entire system and it is possible to have access to all firmware calls. Does exist something similar with EFI. Thanks. -- Vidal Bruno, (770-4271) SSD-HA Team, HP-UX & LINUX Support bruno_vidal@admin.france.hp.com