Messages in this thread | | | Date | Thu, 28 Nov 2013 00:13:05 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH] Add a text_poke syscall v2 |
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On Wed, Nov 27, 2013 at 03:04:41PM -0800, Linus Torvalds wrote: > So sysexit/sysret doesn't count as a serializing instruction, no. > But it doesn't need to, because *self*-modifying code doesn't need a > serializing instruction, only a branch. It's only *cross*-modifying > code that needs a serializing instruction. > > So the IPI is sufficient for the cross-modifying case, and the sysret > is sufficient for the self-modifying case. And we also don't need > to worry about "what happens if we schedule to another CPU, and > self-modifying becomes cross-modifying", because the scheduling will > then do the serializing instruction. > > So IPI for other CPU's (limited to the mm-mask) and just a system call > for local CPU should be perfectly fine.
Cool, so basically an empty dummy syscall IPI-ed to all cores. With a big fat comment on top.
:-)
-- Regards/Gruss, Boris.
Sent from a fat crate under my desk. Formatting is fine. --
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