On Wed, 2023-05-17 at 17:49 +1000, Michael Ellerman wrote: > Nageswara reported that /proc/self/status was showing "vulnerable" > for > the Speculation_Store_Bypass feature on Power10, eg: > > $ grep Speculation_Store_Bypass: /proc/self/status > Speculation_Store_Bypass: vulnerable > > But at the same time the sysfs files, and lscpu, were showing "Not > affected". > > This turns out to simply be a bug in the reporting of the > Speculation_Store_Bypass, aka. PR_SPEC_STORE_BYPASS, case. > > When SEC_FTR_STF_BARRIER was added, so that firmware could > communicate > the vulnerability was not present, the code in ssb_prctl_get() was > not > updated to check the new flag. > > So add the check for SEC_FTR_STF_BARRIER being disabled. Rather than > adding the new check to the existing if block and expanding the > comment > to cover both cases, rewrite the three cases to be separate so they > can > be commented separately for clarity. > > Fixes: 84ed26fd00c5 ("powerpc/security: Add a security feature for > STF barrier") > Cc: sta...@vger.kernel.org # v5.14+ > Reported-by: Nageswara R Sastry <rnsas...@linux.ibm.com> > Signed-off-by: Michael Ellerman <m...@ellerman.id.au>
Reviewed-by: Russell Currey <rus...@russell.cc>