On Sat, Jan 06, 2018 at 09:20:59PM -0800, Randy Dunlap wrote: > On 01/05/18 06:57, Mark Rutland wrote: > > Document the rationale and usage of the new nospec*() helpers. > > > > Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx> > > Signed-off-by: Will Deacon <will.deacon@xxxxxxx> > > Cc: Dan Williams <dan.j.williams@xxxxxxxxx> > > Cc: Jonathan Corbet <corbet@xxxxxxx> > > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > > --- > > Documentation/speculation.txt | 166 ++++++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 166 insertions(+) > > create mode 100644 Documentation/speculation.txt > > > > diff --git a/Documentation/speculation.txt b/Documentation/speculation.txt > > new file mode 100644 > > index 000000000000..748fcd4dcda4 > > --- /dev/null > > +++ b/Documentation/speculation.txt > > @@ -0,0 +1,166 @@ > > + > > +Typically speculative execution cannot be observed from architectural state, > > +such as the contents of registers. However, in some cases it is possible to > > +observe its impact on microarchitectural state, such as the presence or > > +absence of data in caches. Such state may form side-channels which can be > > +observed to extract secret information. > > I'm curious about what it takes to observe this... > > or is that covered in the exploit papers? That's covered elsewhere, e.g. https://googleprojectzero.blogspot.co.uk/2018/01/reading-privileged-memory-with-side.html I'll add some references. Thanks, Mark.
