| Message ID | 1471610295-1456-2-git-send-email-marc.zyngier@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Aug 19, 2016 at 01:38:11PM +0100, Marc Zyngier wrote: > The ARM ARM asserts that having the IT bits set in ARM mode is > unpredictable. But should a CPU do that (and still be able to > run correctly), we shouldn't kill the system. > > So let's drop the BUG_ON that checks for this, as it is not > very helpful. > > Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> not sure how this relates to the series, but looks fine otherwise: Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> > --- > arch/arm/kvm/emulate.c | 4 +--- > arch/arm64/kvm/emulate.c | 4 +--- > 2 files changed, 2 insertions(+), 6 deletions(-) > > diff --git a/arch/arm/kvm/emulate.c b/arch/arm/kvm/emulate.c > index af93e3f..eda9ddd 100644 > --- a/arch/arm/kvm/emulate.c > +++ b/arch/arm/kvm/emulate.c > @@ -221,9 +221,7 @@ static void kvm_adjust_itstate(struct kvm_vcpu *vcpu) > unsigned long cpsr = *vcpu_cpsr(vcpu); > bool is_arm = !(cpsr & PSR_T_BIT); > > - BUG_ON(is_arm && (cpsr & PSR_IT_MASK)); > - > - if (!(cpsr & PSR_IT_MASK)) > + if (is_arm || !(cpsr & PSR_IT_MASK)) > return; > > cond = (cpsr & 0xe000) >> 13; > diff --git a/arch/arm64/kvm/emulate.c b/arch/arm64/kvm/emulate.c > index f87d8fb..df76590 100644 > --- a/arch/arm64/kvm/emulate.c > +++ b/arch/arm64/kvm/emulate.c > @@ -120,9 +120,7 @@ static void kvm_adjust_itstate(struct kvm_vcpu *vcpu) > unsigned long cpsr = *vcpu_cpsr(vcpu); > bool is_arm = !(cpsr & COMPAT_PSR_T_BIT); > > - BUG_ON(is_arm && (cpsr & COMPAT_PSR_IT_MASK)); > - > - if (!(cpsr & COMPAT_PSR_IT_MASK)) > + if (is_arm || !(cpsr & COMPAT_PSR_IT_MASK)) > return; > > cond = (cpsr & 0xe000) >> 13; > -- > 2.1.4 > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 01/09/16 12:56, Christoffer Dall wrote: > On Fri, Aug 19, 2016 at 01:38:11PM +0100, Marc Zyngier wrote: >> The ARM ARM asserts that having the IT bits set in ARM mode is >> unpredictable. But should a CPU do that (and still be able to >> run correctly), we shouldn't kill the system. >> >> So let's drop the BUG_ON that checks for this, as it is not >> very helpful. >> >> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> > > not sure how this relates to the series, but looks fine otherwise: In the following patch, I'm moving the whole function to be an inline that will be used in HYP as well. A BUG_ON in HYP is a pretty tasteless thing to do, so I opted for removing it here. But your remark on the following patch makes more sense over all. I'll follow up there. > Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Thanks, M.
diff --git a/arch/arm/kvm/emulate.c b/arch/arm/kvm/emulate.c index af93e3f..eda9ddd 100644 --- a/arch/arm/kvm/emulate.c +++ b/arch/arm/kvm/emulate.c @@ -221,9 +221,7 @@ static void kvm_adjust_itstate(struct kvm_vcpu *vcpu) unsigned long cpsr = *vcpu_cpsr(vcpu); bool is_arm = !(cpsr & PSR_T_BIT); - BUG_ON(is_arm && (cpsr & PSR_IT_MASK)); - - if (!(cpsr & PSR_IT_MASK)) + if (is_arm || !(cpsr & PSR_IT_MASK)) return; cond = (cpsr & 0xe000) >> 13; diff --git a/arch/arm64/kvm/emulate.c b/arch/arm64/kvm/emulate.c index f87d8fb..df76590 100644 --- a/arch/arm64/kvm/emulate.c +++ b/arch/arm64/kvm/emulate.c @@ -120,9 +120,7 @@ static void kvm_adjust_itstate(struct kvm_vcpu *vcpu) unsigned long cpsr = *vcpu_cpsr(vcpu); bool is_arm = !(cpsr & COMPAT_PSR_T_BIT); - BUG_ON(is_arm && (cpsr & COMPAT_PSR_IT_MASK)); - - if (!(cpsr & COMPAT_PSR_IT_MASK)) + if (is_arm || !(cpsr & COMPAT_PSR_IT_MASK)) return; cond = (cpsr & 0xe000) >> 13;
The ARM ARM asserts that having the IT bits set in ARM mode is unpredictable. But should a CPU do that (and still be able to run correctly), we shouldn't kill the system. So let's drop the BUG_ON that checks for this, as it is not very helpful. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> --- arch/arm/kvm/emulate.c | 4 +--- arch/arm64/kvm/emulate.c | 4 +--- 2 files changed, 2 insertions(+), 6 deletions(-)