On Sat, May 20, 2017 at 11:20:34AM -0500, Josh Poimboeuf wrote: > But then, if we're going that far, why not just have objtool reformat > the data into something much simpler? It already has the knowledge > to do so. Then we don't have to jump through all those hoops to > justify jumping through more hoops in the kernel (i.e., having a > complex DWARF state machine). With a simple debuginfo format, the > kernel unwinder is simple enough that we don't need to validate its > functionality in a simulator.
I should clarify that it doesn't have to be objtool which does this. It could instead be a simple DWARF-to-undwarf conversion tool which runs during the vmlinux linking stage. Anyway we're both proposing simplifying the DWARF data into an easier-to-parse format. I think the question is whether we want that simplification process to happen in the kernel (in the middle of a kernel unwind operation), or at build time. -- Josh
