Messages in this thread | | | Date | Thu, 18 Jun 2015 12:14:34 +0200 | From | Ingo Molnar <> | Subject | Re: [RFC/INCOMPLETE 00/13] x86: Rewrite exit-to-userspace code |
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* Andy Lutomirski <luto@amacapital.net> wrote:
> > So assuming you fix the UML build I'm inclined to go for it, even in this > > incomplete form, to increase testing coverage. > > > > Doing that will also decrease ongoing merge friction between your work and > > other entry code cleanups ... > > Sounds good to me. I'm not convinced this is 4.2 material, though. Would it go > in a separate branch for now?
Please send it out as a separate series, on top of -tip, I'll probably stick it into a separate branch for the time being.
> On a related note, do you have any idea what work_notifysig_v86 in entry_32.S is > for? It seems unnecessary and wrong to me. Unnecessary because we have > return_to_32bit. Wrong because I don't see how we can reliably enter vm86 mode > if we have exit work enabled -- one of the giant turds in vm86_32.c literally > jumps from C code to resume_userspace on vm86 entry, and resume_userspace > promptly checks for work and might land in work_notifysig_v86 before we ever > make it to v8086/user mode. > > I think it may actually be impossible to use vm86 under ptrace. ISTR I had some > trouble when trying to strace my test case...
Should be tested really, I'm all for removing it if simple vm86 mode games continue to work ;-)
Thanks,
Ingo
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