@@ -49,8 +49,12 @@ typedef u32 sysmmu_pte_t;
#define LPAGE_MASK (~(LPAGE_SIZE - 1))
#define SPAGE_MASK (~(SPAGE_SIZE - 1))
-#define lv1ent_fault(sent) (((*(sent) & 3) == 0) || ((*(sent) & 3) == 3))
-#define lv1ent_page(sent) ((*(sent) & 3) == 1)
+#define lv1ent_fault(sent) ((*(sent) == ZERO_LV2LINK) || \
+ ((*(sent) & 3) == 0) || ((*(sent) & 3) == 3))
+#define lv1ent_zero(sent) (*(sent) == ZERO_LV2LINK)
+#define lv1ent_page_zero(sent) ((*(sent) & 3) == 1)
+#define lv1ent_page(sent) ((*(sent) != ZERO_LV2LINK) && \
+ ((*(sent) & 3) == 1))
#define lv1ent_section(sent) ((*(sent) & 3) == 2)
#define lv2ent_fault(pent) ((*(pent) & 3) == 0)
@@ -138,6 +142,8 @@ static u32 lv2ent_offset(sysmmu_iova_t iova)
entry)
static struct kmem_cache *lv2table_kmem_cache;
+static sysmmu_pte_t *zero_lv2_table;
+#define ZERO_LV2LINK mk_lv1ent_page(virt_to_phys(zero_lv2_table))
static sysmmu_pte_t *section_entry(sysmmu_pte_t *pgtable, sysmmu_iova_t iova)
{
@@ -545,6 +551,35 @@ static bool exynos_sysmmu_disable(struct device *dev)
return disabled;
}
+static void __sysmmu_tlb_invalidate_flpdcache(struct sysmmu_drvdata *data,
+ sysmmu_iova_t iova)
+{
+ if (__raw_sysmmu_version(data) == MAKE_MMU_VER(3, 3))
+ __raw_writel(iova | 0x1, data->sfrbase + REG_MMU_FLUSH_ENTRY);
+}
+
+static void sysmmu_tlb_invalidate_flpdcache(struct device *dev,
+ sysmmu_iova_t iova)
+{
+ struct sysmmu_list_data *list;
+
+ for_each_sysmmu_list(dev, list) {
+ unsigned long flags;
+ struct sysmmu_drvdata *data = dev_get_drvdata(list->sysmmu);
+
+ if (!IS_ERR(data->clk_master))
+ clk_enable(data->clk_master);
+
+ spin_lock_irqsave(&data->lock, flags);
+ if (is_sysmmu_active(data) && data->powered_on)
+ __sysmmu_tlb_invalidate_flpdcache(data, iova);
+ spin_unlock_irqrestore(&data->lock, flags);
+
+ if (!IS_ERR(data->clk_master))
+ clk_disable(data->clk_master);
+ }
+}
+
static void sysmmu_tlb_invalidate_entry(struct device *dev, sysmmu_iova_t iova,
size_t size)
{
@@ -848,21 +883,32 @@ static inline void pgtable_flush(void *vastart, void *vaend)
static int exynos_iommu_domain_init(struct iommu_domain *domain)
{
struct exynos_iommu_domain *priv;
+ int i;
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
- priv->pgtable = (sysmmu_pte_t *)__get_free_pages(
- GFP_KERNEL | __GFP_ZERO, 2);
+ priv->pgtable = (sysmmu_pte_t *)__get_free_pages(GFP_KERNEL, 2);
if (!priv->pgtable)
goto err_pgtable;
- priv->lv2entcnt = (short *)__get_free_pages(
- GFP_KERNEL | __GFP_ZERO, 1);
+ priv->lv2entcnt = (short *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 1);
if (!priv->lv2entcnt)
goto err_counter;
+ /* w/a of System MMU v3.3 to prevent caching 1MiB mapping */
+ for (i = 0; i < NUM_LV1ENTRIES; i += 8) {
+ priv->pgtable[i + 0] = ZERO_LV2LINK;
+ priv->pgtable[i + 1] = ZERO_LV2LINK;
+ priv->pgtable[i + 2] = ZERO_LV2LINK;
+ priv->pgtable[i + 3] = ZERO_LV2LINK;
+ priv->pgtable[i + 4] = ZERO_LV2LINK;
+ priv->pgtable[i + 5] = ZERO_LV2LINK;
+ priv->pgtable[i + 6] = ZERO_LV2LINK;
+ priv->pgtable[i + 7] = ZERO_LV2LINK;
+ }
+
pgtable_flush(priv->pgtable, priv->pgtable + NUM_LV1ENTRIES);
spin_lock_init(&priv->lock);
@@ -975,8 +1021,8 @@ static void exynos_iommu_detach_device(struct iommu_domain *domain,
dev_dbg(dev, "%s: No IOMMU is attached\n", __func__);
}
-static sysmmu_pte_t *alloc_lv2entry(sysmmu_pte_t *sent, sysmmu_iova_t iova,
- short *pgcounter)
+static sysmmu_pte_t *alloc_lv2entry(struct exynos_iommu_domain *priv,
+ sysmmu_pte_t *sent, sysmmu_iova_t iova, short *pgcounter)
{
if (lv1ent_section(sent)) {
WARN(1, "Trying mapping on %#08x mapped with 1MiB page", iova);
@@ -985,6 +1031,7 @@ static sysmmu_pte_t *alloc_lv2entry(sysmmu_pte_t *sent, sysmmu_iova_t iova,
if (lv1ent_fault(sent)) {
sysmmu_pte_t *pent;
+ bool need_flush_flpd_cache = lv1ent_zero(sent);
pent = kmem_cache_zalloc(lv2table_kmem_cache, GFP_ATOMIC);
BUG_ON((unsigned int)pent & (LV2TABLE_SIZE - 1));
@@ -995,12 +1042,39 @@ static sysmmu_pte_t *alloc_lv2entry(sysmmu_pte_t *sent, sysmmu_iova_t iova,
*pgcounter = NUM_LV2ENTRIES;
pgtable_flush(pent, pent + NUM_LV2ENTRIES);
pgtable_flush(sent, sent + 1);
+
+ /*
+ * If pretched SLPD is a fault SLPD in zero_l2_table, FLPD cache
+ * may caches the address of zero_l2_table. This function
+ * replaces the zero_l2_table with new L2 page table to write
+ * valid mappings.
+ * Accessing the valid area may cause page fault since FLPD
+ * cache may still caches zero_l2_table for the valid area
+ * instead of new L2 page table that have the mapping
+ * information of the valid area
+ * Thus any replacement of zero_l2_table with other valid L2
+ * page table must involve FLPD cache invalidation for System
+ * MMU v3.3.
+ * FLPD cache invalidation is performed with TLB invalidation
+ * by VPN without blocking. It is safe to invalidate TLB without
+ * blocking because the target address of TLB invalidation is
+ * not currently mapped.
+ */
+ if (need_flush_flpd_cache) {
+ struct exynos_iommu_owner *owner;
+ spin_lock(&priv->lock);
+ list_for_each_entry(owner, &priv->clients, client)
+ sysmmu_tlb_invalidate_flpdcache(
+ owner->dev, iova);
+ spin_unlock(&priv->lock);
+ }
}
return page_entry(sent, iova);
}
-static int lv1set_section(sysmmu_pte_t *sent, sysmmu_iova_t iova,
+static int lv1set_section(struct exynos_iommu_domain *priv,
+ sysmmu_pte_t *sent, sysmmu_iova_t iova,
phys_addr_t paddr, short *pgcnt)
{
if (lv1ent_section(sent)) {
@@ -1020,6 +1094,18 @@ static int lv1set_section(sysmmu_pte_t *sent, sysmmu_iova_t iova,
*pgcnt = 0;
}
+ spin_lock(&priv->lock);
+ if (lv1ent_page_zero(sent)) {
+ struct exynos_iommu_owner *owner;
+ /*
+ * Flushing FLPD cache in System MMU v3.3 that may cache a FLPD
+ * entry by speculative prefetch of SLPD which has no mapping.
+ */
+ list_for_each_entry(owner, &priv->clients, client)
+ sysmmu_tlb_invalidate_flpdcache(owner->dev, iova);
+ }
+ spin_unlock(&priv->lock);
+
*sent = mk_lv1ent_sect(paddr);
pgtable_flush(sent, sent + 1);
@@ -1059,6 +1145,32 @@ static int lv2set_page(sysmmu_pte_t *pent, phys_addr_t paddr, size_t size,
return 0;
}
+/*
+ * *CAUTION* to the I/O virtual memory managers that support exynos-iommu:
+ *
+ * System MMU v3.x have an advanced logic to improve address translation
+ * performance with caching more page table entries by a page table walk.
+ * However, the logic has a bug that caching fault page table entries and System
+ * MMU reports page fault if the cached fault entry is hit even though the fault
+ * entry is updated to a valid entry after the entry is cached.
+ * To prevent caching fault page table entries which may be updated to valid
+ * entries later, the virtual memory manager should care about the w/a about the
+ * problem. The followings describe w/a.
+ *
+ * Any two consecutive I/O virtual address regions must have a hole of 128KiB
+ * in maximum to prevent misbehavior of System MMU 3.x. (w/a of h/w bug)
+ *
+ * Precisely, any start address of I/O virtual region must be aligned by
+ * the following sizes for System MMU v3.1 and v3.2.
+ * System MMU v3.1: 128KiB
+ * System MMU v3.2: 256KiB
+ *
+ * Because System MMU v3.3 caches page table entries more aggressively, it needs
+ * more w/a.
+ * - Any two consecutive I/O virtual regions must be have a hole of larger size
+ * than or equal size to 128KiB.
+ * - Start address of an I/O virtual region must be aligned by 128KiB.
+ */
static int exynos_iommu_map(struct iommu_domain *domain, unsigned long l_iova,
phys_addr_t paddr, size_t size, int prot)
{
@@ -1075,12 +1187,12 @@ static int exynos_iommu_map(struct iommu_domain *domain, unsigned long l_iova,
entry = section_entry(priv->pgtable, iova);
if (size == SECT_SIZE) {
- ret = lv1set_section(entry, iova, paddr,
+ ret = lv1set_section(priv, entry, iova, paddr,
&priv->lv2entcnt[lv1ent_offset(iova)]);
} else {
sysmmu_pte_t *pent;
- pent = alloc_lv2entry(entry, iova,
+ pent = alloc_lv2entry(priv, entry, iova,
&priv->lv2entcnt[lv1ent_offset(iova)]);
if (IS_ERR(pent))
@@ -1099,11 +1211,24 @@ static int exynos_iommu_map(struct iommu_domain *domain, unsigned long l_iova,
return ret;
}
+static void exynos_iommu_tlb_invalidate_entry(struct exynos_iommu_domain *priv,
+ sysmmu_iova_t iova, size_t size)
+{
+ struct exynos_iommu_owner *owner;
+ unsigned long flags;
+
+ spin_lock_irqsave(&priv->lock, flags);
+
+ list_for_each_entry(owner, &priv->clients, client)
+ sysmmu_tlb_invalidate_entry(owner->dev, iova, size);
+
+ spin_unlock_irqrestore(&priv->lock, flags);
+}
+
static size_t exynos_iommu_unmap(struct iommu_domain *domain,
unsigned long l_iova, size_t size)
{
struct exynos_iommu_domain *priv = domain->priv;
- struct exynos_iommu_owner *owner;
sysmmu_iova_t iova = (sysmmu_iova_t)l_iova;
sysmmu_pte_t *ent;
size_t err_pgsize;
@@ -1121,7 +1246,7 @@ static size_t exynos_iommu_unmap(struct iommu_domain *domain,
goto err;
}
- *ent = 0;
+ *ent = ZERO_LV2LINK; /* w/a for h/w bug in Sysmem MMU v3.3 */
pgtable_flush(ent, ent + 1);
size = SECT_SIZE;
goto done;
@@ -1164,10 +1289,7 @@ static size_t exynos_iommu_unmap(struct iommu_domain *domain,
done:
spin_unlock_irqrestore(&priv->pgtablelock, flags);
- spin_lock_irqsave(&priv->lock, flags);
- list_for_each_entry(owner, &priv->clients, client)
- sysmmu_tlb_invalidate_entry(owner->dev, iova, size);
- spin_unlock_irqrestore(&priv->lock, flags);
+ exynos_iommu_tlb_invalidate_entry(priv, iova, size);
return size;
err:
@@ -1264,6 +1386,14 @@ static int __init exynos_iommu_init(void)
goto err_reg_driver;
}
+ zero_lv2_table = kmem_cache_zalloc(lv2table_kmem_cache, GFP_KERNEL);
+ if (zero_lv2_table == NULL) {
+ pr_err("%s: Failed to allocate zero level2 page table\n",
+ __func__);
+ ret = -ENOMEM;
+ goto err_zero_lv2;
+ }
+
ret = bus_set_iommu(&platform_bus_type, &exynos_iommu_ops);
if (ret) {
pr_err("%s: Failed to register exynos-iommu driver.\n",
@@ -1273,6 +1403,8 @@ static int __init exynos_iommu_init(void)
return 0;
err_set_iommu:
+ kmem_cache_free(lv2table_kmem_cache, zero_lv2_table);
+err_zero_lv2:
platform_driver_unregister(&exynos_sysmmu_driver);
err_reg_driver:
kmem_cache_destroy(lv2table_kmem_cache);