Messages in this thread | | | Date | Fri, 8 Mar 2019 22:33:43 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 20/20] objtool: Add Direction Flag validation |
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On Fri, Mar 08, 2019 at 03:16:03PM -0600, Josh Poimboeuf wrote: > On Thu, Mar 07, 2019 at 12:45:31PM +0100, Peter Zijlstra wrote: > > Having DF escape is BAD(tm). > > > > Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> > > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> > > Can you elaborate on why (in the patch description)? Did this actually > find any occurrences?
Nope, didn't find anything. Also, all DF users are in asm so I didn't really expect any. Having it escape would probably result in fairly instant wreckage though.
DF=1 results in things like rep mov going _backwards_.
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