On Fri, Mar 25, 2011 at 1:11 PM, Ulrich Weigand <ulrich.weig...@de.ibm.com> wrote: > Dave Martin <dave.mar...@linaro.org> wrote: >> > So to summarize: the kernel will write additional note sections as if >> > generated via user_regset_view, containing the PTRACE_GETVFPREGS data. >> > >> > Note name: "LINUX" >> >> Why "LINUX" and not "CORE"? I don't understand the distinction... are >> the "CORE" notes common to all platforms / all ELF implementations? > > Because that's what user_regset_view would do; all notes except the > standard ones (NT_PRPSINFO, NT_PRSTATUS, NT_PRFPREG, NT_AUXV) have a > note name of "LINUX". I'm not completely sure about the rationale, > but presumably it is indeed because the standard notes are more or less > common across multiple platforms.
OK -- I'm happy to go along with this. It's easy to change if someone doesn't like it, though I expect it will be accepted as-is. > >> > Note type: t.b.d. [*] >> > >> > [*] Looking at elf.h a logical name/value might be: >> > >> > #define NT_ARM_VFP 0x400 /* ARM VFP/NEON > registers */ >> > >> > >> > GDB support along those lines ought to be straightforward. >> >> It's been suggested that the new note should include a version/flags >> field alongside the ptrace-like register dump, so that if the format >> turns out to be inadequate / broken, it can be extended in a >> compatible way. >> >> However, nothing else in the coredump or the ptrace interface seems to >> have such versioning implementation. Ptrace gets extended by adding >> more and more ptrace call types instead. Adding version fields, while >> sensible, seems inconsistent with the current implementation. >> >> What's your view on adding a flags field to the VFP state dump? > > Again, if we want to use (or mimic) the user_regset_view mechanism, > there is no choice in any of this; the content of the note will be > exactly identical to the content of the ptrace buffer. Since this > is the way everybody else is using, I think we'd have to have really > good arguments for deviating from it; I'm not sure I see those. > > The usual way to deal with changes to the register set is to define > *new* regset structures, which then translates to new ptrace commands > and new core files notes, which are used instead of or in addition to > the old ones ... I was indeed thinking that it might be a good idea to take this opportunity to migrate to using regsets; though for simplicity, I'll probably avoid this for the first iteration. Will this have any impact on the ptrace interface? Cheers ---Dave _______________________________________________ linaro-dev mailing list linaro-dev@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-dev
