| Message ID | 91b92d8182d2f114d92c95689fcd4bb1a8dda1b0.1554396090.git.jpoimboe@redhat.com (mailing list archive) |
|---|---|
| State | RFC |
| Headers | show |
| Series | cpu/speculation: Add 'cpu_spec_mitigations=' cmdline options | expand |
On Thu, 4 Apr 2019, Josh Poimboeuf wrote: > 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. [ ... snip ... ] > - if (!no_nospec) > + if (!no_nospec && cpu_spec_mitigations != CPU_SPEC_MITIGATIONS_OFF) '!no_nospec' is something that I am sure will come back to hunt me in my bad dreams. But that's been there already, and fixing it is out of scope of this patch. Other than that, as discussed previously -- I really like this new global option. Feel free to add Reviewed-by: Jiri Kosina <jkosina@suse.cz> for the whole set. Thanks,
Will be joining in ~ 5 mins. Getting Chromium set up here. ----- Original Message ----- > From: "Jiri Kosina" <jikos@kernel.org> > To: "Josh Poimboeuf" <jpoimboe@redhat.com> > Cc: "Peter Zijlstra" <peterz@infradead.org>, "Heiko Carstens" <heiko.carstens@de.ibm.com>, "Paul Mackerras" > <paulus@samba.org>, "H . Peter Anvin" <hpa@zytor.com>, "Ingo Molnar" <mingo@kernel.org>, "Andrea Arcangeli" > <aarcange@redhat.com>, linux-s390@vger.kernel.org, x86@kernel.org, "Will Deacon" <will.deacon@arm.com>, "Linus > Torvalds" <torvalds@linux-foundation.org>, "Catalin Marinas" <catalin.marinas@arm.com>, "Waiman Long" > <longman@redhat.com>, linux-arch@vger.kernel.org, "Jon Masters" <jcm@redhat.com>, "Borislav Petkov" <bp@alien8.de>, > "Andy Lutomirski" <luto@kernel.org>, "Thomas Gleixner" <tglx@linutronix.de>, linux-arm-kernel@lists.infradead.org, > "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>, linux-kernel@vger.kernel.org, "Tyler Hicks" <tyhicks@canonical.com>, > "Martin Schwidefsky" <schwidefsky@de.ibm.com>, linuxppc-dev@lists.ozlabs.org > Sent: Thursday, April 4, 2019 2:49:05 PM > Subject: Re: [PATCH RFC 3/5] powerpc/speculation: Add support for 'cpu_spec_mitigations=' cmdline options > On Thu, 4 Apr 2019, Josh Poimboeuf wrote: > >> 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. > [ ... snip ... ] >> - if (!no_nospec) >> + if (!no_nospec && cpu_spec_mitigations != CPU_SPEC_MITIGATIONS_OFF) > > '!no_nospec' is something that I am sure will come back to hunt me in my > bad dreams. > > But that's been there already, and fixing it is out of scope of this > patch. Other than that, as discussed previously -- I really like this new > global option. Feel free to add > > Reviewed-by: Jiri Kosina <jkosina@suse.cz> > > for the whole set. > > Thanks, > > -- > Jiri Kosina > SUSE Labs
Josh Poimboeuf <jpoimboe@redhat.com> 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@redhat.com> > --- > 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. > 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. > @@ -116,7 +116,7 @@ static int __init handle_nospectre_v2(char *p) > early_param("nospectre_v2", handle_nospectre_v2); > void setup_spectre_v2(void) > { > - if (no_spectrev2) > + if (no_spectrev2 || cpu_spec_mitigations == CPU_SPEC_MITIGATIONS_OFF) > do_btb_flush_fixups(); > else > btb_flush_enabled = true; > @@ -300,7 +300,7 @@ void setup_stf_barrier(void) > > stf_enabled_flush_types = type; > > - if (!no_stf_barrier) > + if (!no_stf_barrier && cpu_spec_mitigations != CPU_SPEC_MITIGATIONS_OFF) > stf_barrier_enable(enable); > } > > diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c > index ba404dd9ce1d..d9d796a66a79 100644 > --- a/arch/powerpc/kernel/setup_64.c > +++ b/arch/powerpc/kernel/setup_64.c > @@ -932,7 +932,7 @@ void setup_rfi_flush(enum l1d_flush_type types, bool enable) > > enabled_flush_types = types; > > - if (!no_rfi_flush) > + if (!no_rfi_flush || cpu_spec_mitigations != CPU_SPEC_MITIGATIONS_OFF) > rfi_flush_enable(enable); > } LGTM. Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) cheers
On Wed, Apr 10, 2019 at 04:06:50PM +1000, Michael Ellerman wrote: > Josh Poimboeuf <jpoimboe@redhat.com> 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@redhat.com> > > --- > > 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.
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] 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); } @@ -116,7 +116,7 @@ static int __init handle_nospectre_v2(char *p) early_param("nospectre_v2", handle_nospectre_v2); void setup_spectre_v2(void) { - if (no_spectrev2) + if (no_spectrev2 || cpu_spec_mitigations == CPU_SPEC_MITIGATIONS_OFF) do_btb_flush_fixups(); else btb_flush_enabled = true; @@ -300,7 +300,7 @@ void setup_stf_barrier(void) stf_enabled_flush_types = type; - if (!no_stf_barrier) + if (!no_stf_barrier && cpu_spec_mitigations != CPU_SPEC_MITIGATIONS_OFF) stf_barrier_enable(enable); } diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c index ba404dd9ce1d..d9d796a66a79 100644 --- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -932,7 +932,7 @@ void setup_rfi_flush(enum l1d_flush_type types, bool enable) enabled_flush_types = types; - if (!no_rfi_flush) + if (!no_rfi_flush || cpu_spec_mitigations != CPU_SPEC_MITIGATIONS_OFF) rfi_flush_enable(enable); }
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@redhat.com> --- 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(-)