[PATCH 8/8] iommu/io-pgtable-arm: Prepare for TTBR1 usage

Will Deacon
2020-01-10T15:29:14Z

From: Robin Murphy <robin.murphy@arm.com>

Now that we can correctly extract top-level indices without relying on
the remaining upper bits being zero, the only remaining impediments to
using a given table for TTBR1 are the address validation on map/unmap
and the awkward TCR translation granule format. Add a quirk so that we
can do the right thing at those points.

Tested-by: Jordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
---
drivers/iommu/io-pgtable-arm.c | 25 +++++++++++++++++++------
include/linux/io-pgtable.h | 4 ++++
2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 846963c87e0f..5e966ef0bacf 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -104,6 +104,10 @@
#define ARM_LPAE_TCR_TG0_64K 1
#define ARM_LPAE_TCR_TG0_16K 2

+#define ARM_LPAE_TCR_TG1_16K 1
+#define ARM_LPAE_TCR_TG1_4K 2
+#define ARM_LPAE_TCR_TG1_64K 3
+
#define ARM_LPAE_TCR_SH_NS 0
#define ARM_LPAE_TCR_SH_OS 2
#define ARM_LPAE_TCR_SH_IS 3
@@ -463,6 +467,7 @@ static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova,
arm_lpae_iopte *ptep = data->pgd;
int ret, lvl = data->start_level;
arm_lpae_iopte prot;
+ long iaext = (long)iova >> cfg->ias;

/* If no access, then nothing to do */
if (!(iommu_prot & (IOMMU_READ | IOMMU_WRITE)))
@@ -471,7 +476,9 @@ static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova,
if (WARN_ON(!size || (size & cfg->pgsize_bitmap) != size))
return -EINVAL;

- if (WARN_ON(iova >> data->iop.cfg.ias || paddr >> data->iop.cfg.oas))
+ if (cfg->quirks & IO_PGTABLE_QUIRK_ARM_TTBR1)
+ iaext = ~iaext;
+ if (WARN_ON(iaext || paddr >> cfg->oas))
return -ERANGE;

prot = arm_lpae_prot_to_pte(data, iommu_prot);
@@ -637,11 +644,14 @@ static size_t arm_lpae_unmap(struct io_pgtable_ops *ops, unsigned long iova,
struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
struct io_pgtable_cfg *cfg = &data->iop.cfg;
arm_lpae_iopte *ptep = data->pgd;
+ long iaext = (long)iova >> cfg->ias;

if (WARN_ON(!size || (size & cfg->pgsize_bitmap) != size))
return 0;

- if (WARN_ON(iova >> data->iop.cfg.ias))
+ if (cfg->quirks & IO_PGTABLE_QUIRK_ARM_TTBR1)
+ iaext = ~iaext;
+ if (WARN_ON(iaext))
return 0;

return __arm_lpae_unmap(data, gather, iova, size, data->start_level, ptep);
@@ -777,9 +787,11 @@ arm_64_lpae_alloc_pgtable_s1(struct io_pgtable_cfg *cfg, void *cookie)
u64 reg;
struct arm_lpae_io_pgtable *data;
typeof(&cfg->arm_lpae_s1_cfg.tcr) tcr = &cfg->arm_lpae_s1_cfg.tcr;
+ bool tg1;

if (cfg->quirks & ~(IO_PGTABLE_QUIRK_ARM_NS |
- IO_PGTABLE_QUIRK_NON_STRICT))
+ IO_PGTABLE_QUIRK_NON_STRICT |
+ IO_PGTABLE_QUIRK_ARM_TTBR1))
return NULL;

data = arm_lpae_alloc_pgtable(cfg);
@@ -797,15 +809,16 @@ arm_64_lpae_alloc_pgtable_s1(struct io_pgtable_cfg *cfg, void *cookie)
tcr->orgn = ARM_LPAE_TCR_RGN_NC;
}

+ tg1 = cfg->quirks & IO_PGTABLE_QUIRK_ARM_TTBR1;
switch (ARM_LPAE_GRANULE(data)) {
case SZ_4K:
- tcr->tg = ARM_LPAE_TCR_TG0_4K;
+ tcr->tg = tg1 ? ARM_LPAE_TCR_TG1_4K : ARM_LPAE_TCR_TG0_4K;
break;
case SZ_16K:
- tcr->tg = ARM_LPAE_TCR_TG0_16K;
+ tcr->tg = tg1 ? ARM_LPAE_TCR_TG1_16K : ARM_LPAE_TCR_TG0_16K;
break;
case SZ_64K:
- tcr->tg = ARM_LPAE_TCR_TG0_64K;
+ tcr->tg = tg1 ? ARM_LPAE_TCR_TG1_64K : ARM_LPAE_TCR_TG0_64K;
break;
}

diff --git a/include/linux/io-pgtable.h b/include/linux/io-pgtable.h
index 40c1b7745fb6..53d53c6c2be9 100644
--- a/include/linux/io-pgtable.h
+++ b/include/linux/io-pgtable.h
@@ -83,12 +83,16 @@ struct io_pgtable_cfg {
* IO_PGTABLE_QUIRK_NON_STRICT: Skip issuing synchronous leaf TLBIs
* on unmap, for DMA domains using the flush queue mechanism for
* delayed invalidation.
+ *
+ * IO_PGTABLE_QUIRK_ARM_TTBR1: (ARM LPAE format) Configure the table
+ * for use in the upper half of a split address space.
*/
#define IO_PGTABLE_QUIRK_ARM_NS BIT(0)
#define IO_PGTABLE_QUIRK_NO_PERMS BIT(1)
#define IO_PGTABLE_QUIRK_TLBI_ON_MAP BIT(2)
#define IO_PGTABLE_QUIRK_ARM_MTK_EXT BIT(3)
#define IO_PGTABLE_QUIRK_NON_STRICT BIT(4)
+ #define IO_PGTABLE_QUIRK_ARM_TTBR1 BIT(5)
unsigned long quirks;
unsigned long pgsize_bitmap;
unsigned int ias;