Messages in this thread | | | Date | Wed, 18 Jan 2012 13:53:12 -0800 | From | "H. Peter Anvin" <> | Subject | Re: Compat 32-bit syscall entry from 64-bit task!? |
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On 01/18/2012 01:51 PM, Roland McGrath wrote: > > There are all the concerns about obscure ABI compatibility with > expectations of existing debuggers and so forth, which Linus has mentioned. > For that I can accept his point that things today so mishandle the > int80-from-64 case that something like a new meaning for high bits of > orig_ax or whatnot in just that case would not be actually problematic. > When you and I were discussing a more general feature of distinguishing > int80 from sysenter from syscall from traps from asynchronous interrupts, > that was of more concern. > > I do feel strongly that any new means of exposing bona fide user state > ought to be done via the user_regset mechanism. (i.e., either overloading > some existing user_regs_struct bits if that truly is harmless to > compatibility, or adding a new regset flavor.) That way it is > automatically recorded in core files, accessible with PTRACE_GETREGSET, > etc. (But I'm not really working on this stuff any more, so I'm out of the > business of arguing strenuously about such opinions.) >
I think we can obviously agree that regsets is the only way to go for any kind of new state.
-hpa
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