On Thu, 2019-04-25 at 16:35 +0100, Dave Martin wrote: > On Thu, Apr 25, 2019 at 08:14:52AM -0700, Yu-cheng Yu wrote: > > On Thu, 2019-04-25 at 12:02 +0100, Dave Martin wrote: > > > [...] > One other question: according to the draft spec at > https://github.com/hjl-tools/linux-abi/wiki/Linux-Extensions-to-gABI, it > looks like the .note.gnu.property section is supposed to be marked with > SHF_ALLOC in object files. > > I think that means that the linker will map it with a PT_LOAD entry in > the program header table in addition to the PT_NOTE that describes the > location of the note. I need to check what the toolchain actually > does. > > If so, can we simply rely on the notes being already mapped, rather than > needing to do additional I/O on the ELF file to fetch the notes? Assuming that is mapped and we do copy_from_user, it will trigger page faults. I suspect in this case reading from the file is better? Yu-cheng
