On Tue, May 07, 2013 at 04:38:04PM +0900, HATAYAMA Daisuke wrote: [..] > >> /* Update the program header offset. */ > >>- phdr_ptr->p_offset = vmcore_off; > >>- vmcore_off = vmcore_off + phdr_ptr->p_memsz; > >>+ phdr_ptr->p_offset = vmcore_off + (paddr - start); > > > >What's paddr-start. Why following is not sufficient. > > > >phdr_ptr->p_offset = vmcore_off > > > > (paddr - start) is offset of the memory program header refers to, > from which kernel memory starts. Pictrically: > > vmcore_off +----------------------+ > | extra memory | > | (non kernel memory) | > phdr->p_offset = +----------------------+ > vmcore_off + (paddr - start) | |\ > | kernel memory | phdr->p_memsz > | |/ > +----------------------+ > | extra memory | > | (non kernel memory) | > vmcore_off + size +----------------------+ Ok, got it. So PT_LOAD header refers to only part of memory and we align start and end to PAGE_SIZE and then add that full chunk to vmcore list. We update the phdr->offset to point to PT_LOAD mapping. vc_list area can contain the page aligned extra memory at the beginning and end and that can be read from old memory if user wishes to. So this is not an issue. Thanks Vivek
