On Wed, Apr 10, 2019 at 04:06:50PM +1000, Michael Ellerman wrote: > Josh Poimboeuf <jpoimboe@xxxxxxxxxx> writes: > > Configure powerpc CPU runtime speculation bug mitigations in accordance > > with the 'cpu_spec_mitigations=' cmdline options. This affects > > Meltdown, Spectre v1, Spectre v2, and Speculative Store Bypass. > > > > The default behavior is unchanged. > > > > Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> > > --- > > Documentation/admin-guide/kernel-parameters.txt | 9 +++++---- > > arch/powerpc/kernel/security.c | 6 +++--- > > arch/powerpc/kernel/setup_64.c | 2 +- > > 3 files changed, 9 insertions(+), 8 deletions(-) > > > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > > index 29dc03971630..0e8eae1e8a25 100644 > > --- a/Documentation/admin-guide/kernel-parameters.txt > > +++ b/Documentation/admin-guide/kernel-parameters.txt > > @@ -2552,10 +2552,11 @@ > > > > off > > Disable all speculative CPU mitigations. > > - Equivalent to: nopti [x86] > > + Equivalent to: nopti [x86, powerpc] > > + nospectre_v1 [powerpc] > > nospectre_v2 [x86] > > Not sure if you meant to omit powerpc from nospectre_v2? > > You have patched it in the code below. Oops. I'll update the documentation. > > spectre_v2_user=off [x86] > > - spec_store_bypass_disable=off [x86] > > + spec_store_bypass_disable=off [x86, powerpc] > > l1tf=off [x86] > > > > auto (default) > > @@ -2568,7 +2569,7 @@ > > Equivalent to: pti=auto [x86] > > spectre_v2=auto [x86] > > spectre_v2_user=auto [x86] > > - spec_store_bypass_disable=auto [x86] > > + spec_store_bypass_disable=auto [x86, powerpc] > > l1tf=flush [x86] > > > > auto,nosmt > > @@ -2579,7 +2580,7 @@ > > Equivalent to: pti=auto [x86] > > spectre_v2=auto [x86] > > spectre_v2_user=auto [x86] > > - spec_store_bypass_disable=auto [x86] > > + spec_store_bypass_disable=auto [x86, powerpc] > > l1tf=flush,nosmt [x86] > > > > mminit_loglevel= > > diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c > > index b33bafb8fcea..5aed4ad729ba 100644 > > --- a/arch/powerpc/kernel/security.c > > +++ b/arch/powerpc/kernel/security.c > > @@ -57,7 +57,7 @@ void setup_barrier_nospec(void) > > enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) && > > security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR); > > > > - if (!no_nospec) > > + if (!no_nospec && cpu_spec_mitigations != CPU_SPEC_MITIGATIONS_OFF) > > enable_barrier_nospec(enable); > > Adding a wrapper func that checks for CPU_SPEC_MITIGATIONS_OFF would > make these a little less verbose, eg: > > if (!no_nospec && !cpu_spec_mitigations_off()) > enable_barrier_nospec(enable); > > But that's a nitpick. Yes, that would be much nicer. I'll probably do something like that in the next version. Thanks. -- Josh
