> OK... FWIW, it sounds like an argument for using it (or a function in > kernel/signal.c that would call it) on all architectures. That was certainly always the intent. But I only touched myself the arch's that I was prepared to test reasonably. > Note that there's an extra complication on alpha and itanic - we have more > than just struct pt_regs * there. If we care about the rest of registers > (struct switch_stack on alpha), we probably need to do something about that. The presumed plan so far was just that anybody would use user_regset for any serious tracer/debugger stuff. That is certainly much more costly on ia64 than passing along a few more values. If anybody ever cares, the tracehook functions' signatures can always be adjusted in the future. > I wonder how alpha and itanic deal with do_coredump(), BTW - it gets > pt_regs, but not the rest... The expectation was that every arch would eventually switch on CORE_DUMP_USE_REGSET. (Looks like so far 12 do and so ~16 don't.) Certainly avoiding the overhead of user_regset for core dumping is not worth any new code complexity or extra arch hooks, since that overhead even on the worst-case arch (ia64) has got to be marginal in comparison to all the memory-copying and i/o going on. For imagined potential tracing/fancier-debugging cases that might be used in high-throughput ways the question would be different, but such uses still remain to be implemented. Thanks, Roland -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
