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-rw-r--r--drivers/iommu/io-pgtable-arm.c117
1 files changed, 104 insertions, 13 deletions
diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 56c31715683a..3c48d95b959f 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -163,8 +163,8 @@
#define ARM_LPAE_MAIR_ATTR_IDX_DEV 2
/* IOPTE accessors */
-#define iopte_deref(pte,d) \
- (__va((pte) & ((1ULL << ARM_LPAE_MAX_ADDR_BITS) - 1) \
+#define iopte_deref(pte, d) \
+ (__va(iopte_val(pte) & ((1ULL << ARM_LPAE_MAX_ADDR_BITS) - 1) \
& ~((1ULL << (d)->pg_shift) - 1)))
#define iopte_type(pte,l) \
@@ -196,12 +196,82 @@ struct arm_lpae_io_pgtable {
typedef u64 arm_lpae_iopte;
+/*
+ * We'll use some ignored bits in table entries to keep track of the number
+ * of page mappings beneath the table. The maximum number of entries
+ * beneath any table mapping in armv8 is 8192 (which is possible at the
+ * 2nd- and 3rd-level when using a 64K granule size). The bits at our
+ * disposal are:
+ *
+ * 4k granule: [58..52], [11..2]
+ * 64k granule: [58..52], [15..2]
+ *
+ * [58..52], [11..2] is enough bits for tracking table mappings at any
+ * level for any granule, so we'll use those.
+ */
+#define BOTTOM_IGNORED_MASK 0x3ff
+#define BOTTOM_IGNORED_SHIFT 2
+#define BOTTOM_IGNORED_NUM_BITS 10
+#define TOP_IGNORED_MASK 0x7fULL
+#define TOP_IGNORED_SHIFT 52
+#define IOPTE_RESERVED_MASK ((BOTTOM_IGNORED_MASK << BOTTOM_IGNORED_SHIFT) | \
+ (TOP_IGNORED_MASK << TOP_IGNORED_SHIFT))
+
+static arm_lpae_iopte iopte_val(arm_lpae_iopte table_pte)
+{
+ return table_pte & ~IOPTE_RESERVED_MASK;
+}
+
+static arm_lpae_iopte _iopte_bottom_ignored_val(arm_lpae_iopte table_pte)
+{
+ return (table_pte & (BOTTOM_IGNORED_MASK << BOTTOM_IGNORED_SHIFT))
+ >> BOTTOM_IGNORED_SHIFT;
+}
+
+static arm_lpae_iopte _iopte_top_ignored_val(arm_lpae_iopte table_pte)
+{
+ return (table_pte & (TOP_IGNORED_MASK << TOP_IGNORED_SHIFT))
+ >> TOP_IGNORED_SHIFT;
+}
+
+static int iopte_tblcnt(arm_lpae_iopte table_pte)
+{
+ return (_iopte_bottom_ignored_val(table_pte) |
+ (_iopte_top_ignored_val(table_pte) << BOTTOM_IGNORED_NUM_BITS));
+}
+
+static void iopte_tblcnt_set(arm_lpae_iopte *table_pte, int val)
+{
+ arm_lpae_iopte pte = iopte_val(*table_pte);
+
+ pte |= ((val & BOTTOM_IGNORED_MASK) << BOTTOM_IGNORED_SHIFT) |
+ (((val & (TOP_IGNORED_MASK << BOTTOM_IGNORED_NUM_BITS))
+ >> BOTTOM_IGNORED_NUM_BITS) << TOP_IGNORED_SHIFT);
+ *table_pte = pte;
+}
+
+static void iopte_tblcnt_sub(arm_lpae_iopte *table_ptep, int cnt)
+{
+ arm_lpae_iopte current_cnt = iopte_tblcnt(*table_ptep);
+
+ current_cnt -= cnt;
+ iopte_tblcnt_set(table_ptep, current_cnt);
+}
+
+static void iopte_tblcnt_add(arm_lpae_iopte *table_ptep, int cnt)
+{
+ arm_lpae_iopte current_cnt = iopte_tblcnt(*table_ptep);
+
+ current_cnt += cnt;
+ iopte_tblcnt_set(table_ptep, current_cnt);
+}
+
static bool suppress_map_failures;
static int arm_lpae_init_pte(struct arm_lpae_io_pgtable *data,
unsigned long iova, phys_addr_t paddr,
arm_lpae_iopte prot, int lvl,
- arm_lpae_iopte *ptep)
+ arm_lpae_iopte *ptep, arm_lpae_iopte *prev_ptep)
{
arm_lpae_iopte pte = prot;
@@ -224,12 +294,17 @@ static int arm_lpae_init_pte(struct arm_lpae_io_pgtable *data,
*ptep = pte;
data->iop.cfg.tlb->flush_pgtable(ptep, sizeof(*ptep), data->iop.cookie);
+
+ if (prev_ptep)
+ iopte_tblcnt_add(prev_ptep, 1);
+
return 0;
}
static int __arm_lpae_map(struct arm_lpae_io_pgtable *data, unsigned long iova,
phys_addr_t paddr, size_t size, arm_lpae_iopte prot,
- int lvl, arm_lpae_iopte *ptep)
+ int lvl, arm_lpae_iopte *ptep,
+ arm_lpae_iopte *prev_ptep)
{
arm_lpae_iopte *cptep, pte;
void *cookie = data->iop.cookie;
@@ -240,7 +315,8 @@ static int __arm_lpae_map(struct arm_lpae_io_pgtable *data, unsigned long iova,
/* If we can install a leaf entry at this level, then do so */
if (size == block_size && (size & data->iop.cfg.pgsize_bitmap))
- return arm_lpae_init_pte(data, iova, paddr, prot, lvl, ptep);
+ return arm_lpae_init_pte(data, iova, paddr, prot, lvl, ptep,
+ prev_ptep);
/* We can't allocate tables at the final level */
if (WARN_ON(lvl >= ARM_LPAE_MAX_LEVELS - 1))
@@ -267,7 +343,8 @@ static int __arm_lpae_map(struct arm_lpae_io_pgtable *data, unsigned long iova,
}
/* Rinse, repeat */
- return __arm_lpae_map(data, iova, paddr, size, prot, lvl + 1, cptep);
+ return __arm_lpae_map(data, iova, paddr, size, prot, lvl + 1, cptep,
+ ptep);
}
static arm_lpae_iopte arm_lpae_prot_to_pte(struct arm_lpae_io_pgtable *data,
@@ -323,7 +400,7 @@ static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova,
return 0;
prot = arm_lpae_prot_to_pte(data, iommu_prot);
- return __arm_lpae_map(data, iova, paddr, size, prot, lvl, ptep);
+ return __arm_lpae_map(data, iova, paddr, size, prot, lvl, ptep, NULL);
}
static int arm_lpae_map_sg(struct io_pgtable_ops *ops, unsigned long iova,
@@ -365,7 +442,7 @@ static int arm_lpae_map_sg(struct io_pgtable_ops *ops, unsigned long iova,
size_t pgsize = iommu_pgsize(
data->iop.cfg.pgsize_bitmap, iova | phys, size);
ret = __arm_lpae_map(data, iova, phys, pgsize, prot,
- lvl, ptep);
+ lvl, ptep, NULL);
if (ret)
goto out_err;
@@ -428,7 +505,8 @@ static void arm_lpae_free_pgtable(struct io_pgtable *iop)
static int arm_lpae_split_blk_unmap(struct arm_lpae_io_pgtable *data,
unsigned long iova, size_t size,
arm_lpae_iopte prot, int lvl,
- arm_lpae_iopte *ptep, size_t blk_size)
+ arm_lpae_iopte *ptep,
+ arm_lpae_iopte *prev_ptep, size_t blk_size)
{
unsigned long blk_start, blk_end;
phys_addr_t blk_paddr;
@@ -450,7 +528,7 @@ static int arm_lpae_split_blk_unmap(struct arm_lpae_io_pgtable *data,
/* __arm_lpae_map expects a pointer to the start of the table */
tablep = &table - ARM_LPAE_LVL_IDX(blk_start, lvl, data);
if (__arm_lpae_map(data, blk_start, blk_paddr, size, prot, lvl,
- tablep) < 0) {
+ tablep, prev_ptep) < 0) {
if (table) {
/* Free the table we allocated */
tablep = iopte_deref(table, data);
@@ -467,7 +545,7 @@ static int arm_lpae_split_blk_unmap(struct arm_lpae_io_pgtable *data,
static int __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
unsigned long iova, size_t size, int lvl,
- arm_lpae_iopte *ptep)
+ arm_lpae_iopte *ptep, arm_lpae_iopte *prev_ptep)
{
arm_lpae_iopte pte;
const struct iommu_gather_ops *tlb = data->iop.cfg.tlb;
@@ -495,6 +573,7 @@ static int __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
return size;
} else if ((lvl == ARM_LPAE_MAX_LEVELS - 2) && !iopte_leaf(pte, lvl)) {
arm_lpae_iopte *table = iopte_deref(pte, data);
+ arm_lpae_iopte *table_base = table;
int tl_offset = ARM_LPAE_LVL_IDX(iova, lvl + 1, data);
int entry_size = (1 << data->pg_shift);
int max_entries = ARM_LPAE_BLOCK_SIZE(lvl, data) / entry_size;
@@ -514,6 +593,15 @@ static int __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
memset(table, 0, table_len);
tlb->flush_pgtable(table, table_len, cookie);
+ iopte_tblcnt_sub(ptep, entries);
+ if (!iopte_tblcnt(*ptep)) {
+ /* no valid mappings left under this table. free it. */
+ *ptep = 0;
+ tlb->flush_pgtable(ptep, sizeof(*ptep), cookie);
+ io_pgtable_free_pages_exact(
+ table_base, max_entries * sizeof(*table_base));
+ }
+
return entries * entry_size;
} else if (iopte_leaf(pte, lvl)) {
/*
@@ -522,12 +610,14 @@ static int __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
*/
return arm_lpae_split_blk_unmap(data, iova, size,
iopte_prot(pte), lvl, ptep,
+ prev_ptep,
blk_size);
}
/* Keep on walkin' */
+ prev_ptep = ptep;
ptep = iopte_deref(pte, data);
- return __arm_lpae_unmap(data, iova, size, lvl + 1, ptep);
+ return __arm_lpae_unmap(data, iova, size, lvl + 1, ptep, prev_ptep);
}
static size_t arm_lpae_unmap(struct io_pgtable_ops *ops, unsigned long iova,
@@ -546,7 +636,8 @@ static size_t arm_lpae_unmap(struct io_pgtable_ops *ops, unsigned long iova,
size_to_unmap = remaining < SZ_2M
? remaining
: iommu_pgsize(data->iop.cfg.pgsize_bitmap, iova, size);
- ret = __arm_lpae_unmap(data, iova, size_to_unmap, lvl, ptep);
+ ret = __arm_lpae_unmap(data, iova, size_to_unmap, lvl, ptep,
+ NULL);
if (ret == 0)
break;
unmapped += ret;
generated by cgit v1.2.3 (git 2.25.1) at 2026-08-14 13:15:29 +0000