| Message ID | 20210729020717.15142-2-yee.lee@mediatek.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add option to disable mte support | expand |
On Thu, 29 Jul 2021 03:07:12 +0100, <yee.lee@mediatek.com> wrote: > > From: Yee Lee <yee.lee@mediatek.com> > > Add an alias, "arm64.nomte", to override id-reg and This isn't just an alias. This patch does two things: - it allows the ID_AA64PFR1_EL1.MTE shadow capability to be set from the command line, - it provides the arm64.nomte alias that sets the above to 0 to disable the MTE feature. > suppress mte feature. s/mte/MTE/ Maybe also worth indicating *why* this is needed. Possible justifications include errata workarounds, performance issues... Pick your own. > > Suggested-by: Marc Zyngier <maz@kernel.org> > Suggested-by: Suzuki K Poulose <suzuki.poulose@arm.com> > Signed-off-by: Yee Lee <yee.lee@mediatek.com> > --- > arch/arm64/kernel/idreg-override.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c > index 53a381a7f65d..d8e606fe3c21 100644 > --- a/arch/arm64/kernel/idreg-override.c > +++ b/arch/arm64/kernel/idreg-override.c > @@ -54,6 +54,7 @@ static const struct ftr_set_desc pfr1 __initconst = { > .override = &id_aa64pfr1_override, > .fields = { > { "bt", ID_AA64PFR1_BT_SHIFT }, > + { "mte", ID_AA64PFR1_MTE_SHIFT}, > {} > }, > }; > @@ -100,6 +101,7 @@ static const struct { > { "arm64.nopauth", > "id_aa64isar1.gpi=0 id_aa64isar1.gpa=0 " > "id_aa64isar1.api=0 id_aa64isar1.apa=0" }, > + { "arm64.nomte", "id_aa64pfr1.mte=0" }, > { "nokaslr", "kaslr.disabled=1" }, > }; > This needs to be documented in kernel-parameters.txt. See the nobti and nopauth options for guidance. Thanks, M.
diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c index 53a381a7f65d..d8e606fe3c21 100644 --- a/arch/arm64/kernel/idreg-override.c +++ b/arch/arm64/kernel/idreg-override.c @@ -54,6 +54,7 @@ static const struct ftr_set_desc pfr1 __initconst = { .override = &id_aa64pfr1_override, .fields = { { "bt", ID_AA64PFR1_BT_SHIFT }, + { "mte", ID_AA64PFR1_MTE_SHIFT}, {} }, }; @@ -100,6 +101,7 @@ static const struct { { "arm64.nopauth", "id_aa64isar1.gpi=0 id_aa64isar1.gpa=0 " "id_aa64isar1.api=0 id_aa64isar1.apa=0" }, + { "arm64.nomte", "id_aa64pfr1.mte=0" }, { "nokaslr", "kaslr.disabled=1" }, };