On Fri, Oct 30, 2020 at 02:53:08PM +0530, Sai Prakash Ranjan wrote:
> Add a quirk IO_PGTABLE_QUIRK_SYS_CACHE to override the
> attributes set in TCR for the page table walker when
> using system cache.
>
> Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@xxxxxxxxxxxxxx>
> ---
> drivers/iommu/io-pgtable-arm.c | 7 ++++++-
> include/linux/io-pgtable.h | 4 ++++
> 2 files changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
> index a7a9bc08dcd1..a356caf1683a 100644
> --- a/drivers/iommu/io-pgtable-arm.c
> +++ b/drivers/iommu/io-pgtable-arm.c
> @@ -761,7 +761,8 @@ arm_64_lpae_alloc_pgtable_s1(struct io_pgtable_cfg *cfg, void *cookie)
>
> if (cfg->quirks & ~(IO_PGTABLE_QUIRK_ARM_NS |
> IO_PGTABLE_QUIRK_NON_STRICT |
> - IO_PGTABLE_QUIRK_ARM_TTBR1))
> + IO_PGTABLE_QUIRK_ARM_TTBR1 |
> + IO_PGTABLE_QUIRK_SYS_CACHE))
> return NULL;
>
> data = arm_lpae_alloc_pgtable(cfg);
> @@ -773,6 +774,10 @@ arm_64_lpae_alloc_pgtable_s1(struct io_pgtable_cfg *cfg, void *cookie)
> tcr->sh = ARM_LPAE_TCR_SH_IS;
> tcr->irgn = ARM_LPAE_TCR_RGN_WBWA;
> tcr->orgn = ARM_LPAE_TCR_RGN_WBWA;
> + } else if (cfg->quirks & IO_PGTABLE_QUIRK_SYS_CACHE) {
> + tcr->sh = ARM_LPAE_TCR_SH_OS;
> + tcr->irgn = ARM_LPAE_TCR_RGN_NC;
> + tcr->orgn = ARM_LPAE_TCR_RGN_WBWA;
Given that this only applies in the case where then page-table walker is
non-coherent, I think we'd be better off renaming the quirk to something
like IO_PGTABLE_QUIRK_ARM_OUTER_WBWA and then rejecting it in the
non-coherent case.
> } else {
> tcr->sh = ARM_LPAE_TCR_SH_OS;
> tcr->irgn = ARM_LPAE_TCR_RGN_NC;
> diff --git a/include/linux/io-pgtable.h b/include/linux/io-pgtable.h
> index 4cde111e425b..86631f711e05 100644
> --- a/include/linux/io-pgtable.h
> +++ b/include/linux/io-pgtable.h
> @@ -86,6 +86,9 @@ struct io_pgtable_cfg {
> *
> * IO_PGTABLE_QUIRK_ARM_TTBR1: (ARM LPAE format) Configure the table
> * for use in the upper half of a split address space.
> + *
> + * IO_PGTABLE_QUIRK_SYS_CACHE: Override the attributes set in TCR for
> + * the page table walker when using system cache.
and then update this accordingly.
Will
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