(2013/12/23 16:46), Namhyung Kim wrote: > On Mon, 23 Dec 2013 06:54:38 +0900, Masami Hiramatsu wrote: >> (2013/12/21 3:03), Arnaldo Carvalho de Melo wrote: >>> Em Fri, Dec 20, 2013 at 10:03:02AM +0000, Masami Hiramatsu escreveu: >> BTW, I'm not sure why debuginfo and nm shows symbol address + 0x400000, >> and why the perf's map/symbol can remove this offset. Could you tell me >> how it works? >> If I can get the offset (0x400000) from binary, I don't need this kind >> of ugly hacks... > > AFAIK the actual symbol address is what nm (and debuginfo) shows. But > perf adjusts symbol address to have a relative address from the start of > mapping (i.e. file offset) like below: > > sym.st_value -= shdr.sh_addr - shdr.sh_offset;
Thanks! this is what I really need! > This way, we can handle mmap and symbol address almost uniformly > (i.e. ip = map->start + symbol->address). But this requires the mmap > event during perf record. For perf probe, we might need to synthesize > mapping info from the section/segment header since it doesn't have the > mmap event. Currently, the dso__new_map() just creates a map starts > from 0. I think the uprobe requires only the relative address, doesn't that? Thank you, -- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu...@hitachi.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
