From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Ameya Mitragotri" Date: Tue, 11 Nov 2003 05:14:42 +0000 Subject: RE: Problem with accessing page tables 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 > Ameya> Now I think the memory for the swapper_pg_dir has > already been > Ameya> allocated. > Ameya> I still get PMD as 0. > > Again, that's normal for memory that hasn't been allocated yet. > > Ameya> Am I doing something fundamentally wrong? > > I don't know. What exactly are you trying to do? Our assumption is that the addresses for the global variables will surely be allocated. (e.g. &panic_timeout should always resolve to an available PGD,PMD,PTE and in the end to a page.) But we see that it is not happening in our case. (In case of swapper_pg_dir one page is already allocated so it should point to a valid page). Any valid address which we have taken from System.map does not resolve down to a valid PTE. (??) The whole purpose of this being, We want to simulate the page tables at user level to analyse a crash dump (LKCD) on IA64. So we dump the page tables and when Lcrash (the user mode tool for analysing dumps) reads this dump, it can seek the page tables and access global variables accordingly. This also will help us eventually in unwinding the dumped stack. Thanks Ameya