Messages in this thread | | | Date | Tue, 23 Aug 2011 16:04:17 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [uml-devel] SYSCALL, ptrace and syscall restart breakages (Re: [RFC] weird crap with vdso on uml/i386) |
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On 08/23/2011 02:20 PM, Linus Torvalds wrote: > On Tue, Aug 23, 2011 at 2:08 PM, H. Peter Anvin <hpa@zytor.com> wrote: >> >> Again, can we steal one of the padding fields to use for that state >> variable? We have two 16-bit padding fields; one for cs and one for ss. > > We can steal them for passing the information to the user, but no, I > don't think we can use them to then take the information *from* the > user. > > Somebody may well be setting up a 'pt_regs' structure on his own, and > simply not fill in the padding, resulting in random data in those > fields. >
That would be fine, I'd think... just gives the user space application enough information to know how it would have to reshuffle the registers if it needs to.
-hpa
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