Re: [PATCH 2/5] iommu/tegra-smmu: Use non-secure register for flushing
24.01.2019 21:29, navneet kumar пишет:
> On 1/17/19 7:25 AM, Dmitry Osipenko wrote:
>> 16.01.2019 23:50, Navneet Kumar пишет:
>>> Use PTB_ASID instead of SMMU_CONFIG to flush smmu.
>>> PTB_ASID can be accessed from non-secure mode, SMMU_CONFIG cannot be.
>>> Using SMMU_CONFIG could pose a problem when kernel doesn't have secure
>>> mode access enabled from boot.
>>>
>>> Signed-off-by: Navneet Kumar
>>> ---
>>> drivers/iommu/tegra-smmu.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
>>> index ee4d8a8..fa175d9 100644
>>> --- a/drivers/iommu/tegra-smmu.c
>>> +++ b/drivers/iommu/tegra-smmu.c
>>> @@ -235,7 +235,7 @@ static inline void smmu_flush_tlb_group(struct
>>> tegra_smmu *smmu,
>>>
>>> static inline void smmu_flush(struct tegra_smmu *smmu)
>>> {
>>> - smmu_readl(smmu, SMMU_CONFIG);
>>> + smmu_readl(smmu, SMMU_PTB_ASID);
>>> }
>>>
>>> static int tegra_smmu_alloc_asid(struct tegra_smmu *smmu, unsigned int
>>> *idp)
>>>
>>
>> Driver writes to SMMU_CONFIG during of the probing. Looks like it's better
>> to drop this patch for now and make it part of a complete solution that will
>> add proper support for a stricter insecure-mode platforms.
>>
> Thanks for the comment Dmitry. On secure platforms, writing to SMMU_CONFIG
> will be a no-op and
> will pose no harm. Having this patch is important because it fixes the
> flushing behavior on
> such platforms, which is critical.
>
> I propose to keep this patch as is, however, i can add more explanation to
> the commit message,
> stating the case of probe and how it will not have any ill effects. Pls
> ACK/NACK, and i shall post
> a V2.
>
Nothing breaks with this change at least for T30. Please extend the commit
message and add a clarifying comment to the code, thanks.
With the clarifying message being addressed:
Reviewed-by: Dmitry Osipenko
Tested-by: Dmitry Osipenko
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Re: [PATCH 2/5] iommu/tegra-smmu: Use non-secure register for flushing
On 1/17/19 7:25 AM, Dmitry Osipenko wrote:
> 16.01.2019 23:50, Navneet Kumar пишет:
>> Use PTB_ASID instead of SMMU_CONFIG to flush smmu.
>> PTB_ASID can be accessed from non-secure mode, SMMU_CONFIG cannot be.
>> Using SMMU_CONFIG could pose a problem when kernel doesn't have secure
>> mode access enabled from boot.
>>
>> Signed-off-by: Navneet Kumar
>> ---
>> drivers/iommu/tegra-smmu.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
>> index ee4d8a8..fa175d9 100644
>> --- a/drivers/iommu/tegra-smmu.c
>> +++ b/drivers/iommu/tegra-smmu.c
>> @@ -235,7 +235,7 @@ static inline void smmu_flush_tlb_group(struct
>> tegra_smmu *smmu,
>>
>> static inline void smmu_flush(struct tegra_smmu *smmu)
>> {
>> -smmu_readl(smmu, SMMU_CONFIG);
>> +smmu_readl(smmu, SMMU_PTB_ASID);
>> }
>>
>> static int tegra_smmu_alloc_asid(struct tegra_smmu *smmu, unsigned int *idp)
>>
>
> Driver writes to SMMU_CONFIG during of the probing. Looks like it's better to
> drop this patch for now and make it part of a complete solution that will add
> proper support for a stricter insecure-mode platforms.
>
Thanks for the comment Dmitry. On secure platforms, writing to SMMU_CONFIG will
be a no-op and
will pose no harm. Having this patch is important because it fixes the flushing
behavior on
such platforms, which is critical.
I propose to keep this patch as is, however, i can add more explanation to the
commit message,
stating the case of probe and how it will not have any ill effects. Pls
ACK/NACK, and i shall post
a V2.
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Re: [PATCH 2/5] iommu/tegra-smmu: Use non-secure register for flushing
16.01.2019 23:50, Navneet Kumar пишет:
> Use PTB_ASID instead of SMMU_CONFIG to flush smmu.
> PTB_ASID can be accessed from non-secure mode, SMMU_CONFIG cannot be.
> Using SMMU_CONFIG could pose a problem when kernel doesn't have secure
> mode access enabled from boot.
>
> Signed-off-by: Navneet Kumar
> ---
> drivers/iommu/tegra-smmu.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
> index ee4d8a8..fa175d9 100644
> --- a/drivers/iommu/tegra-smmu.c
> +++ b/drivers/iommu/tegra-smmu.c
> @@ -235,7 +235,7 @@ static inline void smmu_flush_tlb_group(struct tegra_smmu
> *smmu,
>
> static inline void smmu_flush(struct tegra_smmu *smmu)
> {
> - smmu_readl(smmu, SMMU_CONFIG);
> + smmu_readl(smmu, SMMU_PTB_ASID);
> }
>
> static int tegra_smmu_alloc_asid(struct tegra_smmu *smmu, unsigned int *idp)
>
Driver writes to SMMU_CONFIG during of the probing. Looks like it's better to
drop this patch for now and make it part of a complete solution that will add
proper support for a stricter insecure-mode platforms.
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[PATCH 2/5] iommu/tegra-smmu: Use non-secure register for flushing
Use PTB_ASID instead of SMMU_CONFIG to flush smmu.
PTB_ASID can be accessed from non-secure mode, SMMU_CONFIG cannot be.
Using SMMU_CONFIG could pose a problem when kernel doesn't have secure
mode access enabled from boot.
Signed-off-by: Navneet Kumar
---
drivers/iommu/tegra-smmu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index ee4d8a8..fa175d9 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -235,7 +235,7 @@ static inline void smmu_flush_tlb_group(struct tegra_smmu
*smmu,
static inline void smmu_flush(struct tegra_smmu *smmu)
{
- smmu_readl(smmu, SMMU_CONFIG);
+ smmu_readl(smmu, SMMU_PTB_ASID);
}
static int tegra_smmu_alloc_asid(struct tegra_smmu *smmu, unsigned int *idp)
--
2.7.4
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