[Crash-utility] ppc64 specific changes to support kdump vmcore

Reposting this patch as it did not made to crash mailing list. Dave, Thanks for adding my different e-mail address to subscriber list. Dave, Attaching a patch which contains ppc64 specific changes to read kdump vmcore. As we are saving pt_regs for all cpus, it reads them from vmcore instead of looking for specific symbols, used for PPC64 netdump/diskdump vmcore. Also, prints regs before any active backtrace. Whereas for netdump vmcore, regs will be displayed anyway as part of exception frame since the 'bt' command displays from the top frame. Verified with "Make Warn" Please let me know if you have any comments. As Badari mentioned, when the sparsemem is enabled, pg_dat->node_mem_map member does not exists. mem_map for each node is scattered across multiple sections and is not contiguous. Therefore, some detailed changes are needed. Until we fix this issue, can we include some hack so that users can use other commands for vmcore analysis. The fix will be: if (MEMBER_EXISTS("pglist_data", "node_mem_map")) readmem(pgdat+OFFSET(pglist_data_node_mem_map), KVADDR, &node_mem_map, sizeof(ulong), "node_mem_map", FAULT_ON_ERROR); [I noticed your response to Badari's posting. Since the sparsemem is effected only for powerpc at this point, we thought, user can use the limited functionality with the above change. (Ex: bt) until we have the complete fix. At least we will be having crash tool available for kdump vmore on ppc64. The sparsemem issue will be fixed soon. Ok, please ignore this if you prefer to wait for the complete fix] Thanks Haren