On Wed, Nov 04, 2020 at 07:14:06PM -0500, Andrea Arcangeli wrote: > This would need updating to make prctl be the new default, but it's > simpler to delete it and refer to the dup. > > Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx> I'll take this too. -Kees > --- > Documentation/admin-guide/hw-vuln/spectre.rst | 51 +------------------ > 1 file changed, 2 insertions(+), 49 deletions(-) > > diff --git a/Documentation/admin-guide/hw-vuln/spectre.rst b/Documentation/admin-guide/hw-vuln/spectre.rst > index 19b897cb1d45..ab7d402c1677 100644 > --- a/Documentation/admin-guide/hw-vuln/spectre.rst > +++ b/Documentation/admin-guide/hw-vuln/spectre.rst > @@ -593,61 +593,14 @@ kernel command line. > Not specifying this option is equivalent to > spectre_v2=auto. > > -For user space mitigation: > - > - spectre_v2_user= > - > - [X86] Control mitigation of Spectre variant 2 > - (indirect branch speculation) vulnerability between > - user space tasks > - > - on > - Unconditionally enable mitigations. Is > - enforced by spectre_v2=on > - > - off > - Unconditionally disable mitigations. Is > - enforced by spectre_v2=off > - > - prctl > - Indirect branch speculation is enabled, > - but mitigation can be enabled via prctl > - per thread. The mitigation control state > - is inherited on fork. > - > - prctl,ibpb > - Like "prctl" above, but only STIBP is > - controlled per thread. IBPB is issued > - always when switching between different user > - space processes. > - > - seccomp > - Same as "prctl" above, but all seccomp > - threads will enable the mitigation unless > - they explicitly opt out. > - > - seccomp,ibpb > - Like "seccomp" above, but only STIBP is > - controlled per thread. IBPB is issued > - always when switching between different > - user space processes. > - > - auto > - Kernel selects the mitigation depending on > - the available CPU features and vulnerability. > - > - Default mitigation: > - If CONFIG_SECCOMP=y then "seccomp", otherwise "prctl" > - > - Not specifying this option is equivalent to > - spectre_v2_user=auto. > - > In general the kernel by default selects > reasonable mitigations for the current CPU. To > disable Spectre variant 2 mitigations, boot with > spectre_v2=off. Spectre variant 1 mitigations > cannot be disabled. > > +For spectre_v2_user see :doc:`/admin-guide/kernel-parameters`. > + > Mitigation selection guide > -------------------------- > > -- Kees Cook
