Hi, After enabling EARLY_DEBUG (and DEBUG in some of the files in arch/powerpc/kernel directory), without forcing the dtstruct variable to 8 byte alignment: # ./kexec -e Starting new kernel console [udbg0] enabled -> early_setup(), dt_ptr: 0x7723000 -> early_init_devtree(c000000007723000) Invalid tag 5 scanning flattened device tree ! search "chosen", depth: 0, uname: Invalid tag 5 scanning flattened device tree ! dt_root_size_cells = 2 dt_root_addr_cells = 2 Invalid tag 5 scanning flattened device tree ! reserving: 128c000 -> 5ec1f7 reserving: 7734000 -> 8cc000 reserving: 7723000 -> f698 Phys. mem: 0 -> move_device_tree <- move_device_tree Scanning CPUs ... Invalid tag 5 scanning flattened device tree ! <- early_init_devtree() Probing machine type ... pSeries ... No suitable machine found ! So device-tree is getting corrupted when dtstruct variable is not aligned to 8 byte variable. This problem is not seen with gcc-3.4. Is it compiler issue? or bug in the code. Regards, M. Mohan Kumar. On Fri, Aug 07, 2009 at 12:24:20AM +1000, Michael Ellerman wrote: > On Wed, 2009-08-05 at 22:19 +0530, M. Mohan Kumar wrote: > > Hi, > > > > When I align the dtstruct variable to 8 bytes, I am able to invoke kdump. > > > > When the line > > static unsigned dtstruct[TREEWORDS], *dt; > > changed to > > static unsigned dtstruct[TREEWORDS] __attribute__ ((aligned (8))), *dt; > > > > kexec-tool works. > > Hmm, odd. > > Can you check how it's aligned without your change? ie. in the original > binary, is it 4 byte aligned? > > When you make the change, is the only thing that changes in the binary > the alignedness of dtstruct, or does it cause other things to move > around? > > I don't think an unaligned dt blob should have any effect on the kernel, > ie. it should copy it in fine, but I'd have to look at the code. > > cheers
