[PATCH v3 15/25] iommu/io-pgtable: Remove non-strict quirk

From: Robin Murphy
Date: Wed Aug 04 2021 - 13:17:00 EST


IO_PGTABLE_QUIRK_NON_STRICT was never a very comfortable fit, since it's
not a quirk of the pagetable format itself. Now that we have a more
appropriate way to convey non-strict unmaps, though, this last of the
non-quirk quirks can also go, and with the flush queue code also now
enforcing its own ordering we can have a lovely cleanup all round.

Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx>

---

v3: New
---
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 3 ---
drivers/iommu/arm/arm-smmu/arm-smmu.c | 3 ---
drivers/iommu/io-pgtable-arm-v7s.c | 12 ++----------
drivers/iommu/io-pgtable-arm.c | 12 ++----------
include/linux/io-pgtable.h | 5 -----
5 files changed, 4 insertions(+), 31 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 4c648da447bf..d9c93d8d193d 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2174,9 +2174,6 @@ static int arm_smmu_domain_finalise(struct iommu_domain *domain,
.iommu_dev = smmu->dev,
};

- if (!iommu_get_dma_strict(domain))
- pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;
-
pgtbl_ops = alloc_io_pgtable_ops(fmt, &pgtbl_cfg, smmu_domain);
if (!pgtbl_ops)
return -ENOMEM;
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index 970d9e4dcd69..a325d4769c17 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -765,9 +765,6 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain,
.iommu_dev = smmu->dev,
};

- if (!iommu_get_dma_strict(domain))
- pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;
-
if (smmu->impl && smmu->impl->init_context) {
ret = smmu->impl->init_context(smmu_domain, &pgtbl_cfg, dev);
if (ret)
diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c
index 5db90d7ce2ec..e84478d39705 100644
--- a/drivers/iommu/io-pgtable-arm-v7s.c
+++ b/drivers/iommu/io-pgtable-arm-v7s.c
@@ -700,14 +700,7 @@ static size_t __arm_v7s_unmap(struct arm_v7s_io_pgtable *data,
ARM_V7S_BLOCK_SIZE(lvl + 1));
ptep = iopte_deref(pte[i], lvl, data);
__arm_v7s_free_table(ptep, lvl + 1, data);
- } else if (iop->cfg.quirks & IO_PGTABLE_QUIRK_NON_STRICT) {
- /*
- * Order the PTE update against queueing the IOVA, to
- * guarantee that a flush callback from a different CPU
- * has observed it before the TLBIALL can be issued.
- */
- smp_wmb();
- } else {
+ } else if (!gather->queued) {
io_pgtable_tlb_add_page(iop, gather, iova, blk_size);
}
iova += blk_size;
@@ -791,8 +784,7 @@ static struct io_pgtable *arm_v7s_alloc_pgtable(struct io_pgtable_cfg *cfg,

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

/* If ARM_MTK_4GB is enabled, the NO_PERMS is also expected. */
diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 053df4048a29..48a5bd8f571d 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -638,14 +638,7 @@ static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
io_pgtable_tlb_flush_walk(iop, iova + i * size, size,
ARM_LPAE_GRANULE(data));
__arm_lpae_free_pgtable(data, lvl + 1, iopte_deref(pte, data));
- } else if (iop->cfg.quirks & IO_PGTABLE_QUIRK_NON_STRICT) {
- /*
- * Order the PTE update against queueing the IOVA, to
- * guarantee that a flush callback from a different CPU
- * has observed it before the TLBIALL can be issued.
- */
- smp_wmb();
- } else {
+ } else if (!gather->queued) {
io_pgtable_tlb_add_page(iop, gather, iova + i * size, size);
}

@@ -825,7 +818,6 @@ arm_64_lpae_alloc_pgtable_s1(struct io_pgtable_cfg *cfg, void *cookie)
bool tg1;

if (cfg->quirks & ~(IO_PGTABLE_QUIRK_ARM_NS |
- IO_PGTABLE_QUIRK_NON_STRICT |
IO_PGTABLE_QUIRK_ARM_TTBR1 |
IO_PGTABLE_QUIRK_ARM_OUTER_WBWA))
return NULL;
@@ -929,7 +921,7 @@ arm_64_lpae_alloc_pgtable_s2(struct io_pgtable_cfg *cfg, void *cookie)
typeof(&cfg->arm_lpae_s2_cfg.vtcr) vtcr = &cfg->arm_lpae_s2_cfg.vtcr;

/* The NS quirk doesn't apply at stage 2 */
- if (cfg->quirks & ~(IO_PGTABLE_QUIRK_NON_STRICT))
+ if (cfg->quirks)
return NULL;

data = arm_lpae_alloc_pgtable(cfg);
diff --git a/include/linux/io-pgtable.h b/include/linux/io-pgtable.h
index c43f3b899d2a..9ba6d9ea316e 100644
--- a/include/linux/io-pgtable.h
+++ b/include/linux/io-pgtable.h
@@ -73,10 +73,6 @@ struct io_pgtable_cfg {
* to support up to 35 bits PA where the bit32, bit33 and bit34 are
* encoded in the bit9, bit4 and bit5 of the PTE respectively.
*
- * 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.
*
@@ -86,7 +82,6 @@ struct io_pgtable_cfg {
#define IO_PGTABLE_QUIRK_ARM_NS BIT(0)
#define IO_PGTABLE_QUIRK_NO_PERMS BIT(1)
#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)
#define IO_PGTABLE_QUIRK_ARM_OUTER_WBWA BIT(6)
unsigned long quirks;
--
2.25.1