[RFC PATCH v3 4/6] swiotlb: Add restricted DMA alloc/free support.
Claire Chang
tientzu at chromium.org
Wed Jan 6 14:41:22 AEDT 2021
Add the functions, swiotlb_alloc and swiotlb_free to support the
memory allocation from restricted DMA pool.
Signed-off-by: Claire Chang <tientzu at chromium.org>
---
include/linux/swiotlb.h | 6 ++
kernel/dma/direct.c | 12 +++
kernel/dma/swiotlb.c | 171 +++++++++++++++++++++++++++++-----------
3 files changed, 144 insertions(+), 45 deletions(-)
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 5135e5636042..84fe96e40685 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -68,6 +68,12 @@ extern void swiotlb_tbl_sync_single(struct device *hwdev,
dma_addr_t swiotlb_map(struct device *dev, phys_addr_t phys,
size_t size, enum dma_data_direction dir, unsigned long attrs);
+void *swiotlb_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
+ unsigned long attrs);
+
+void swiotlb_free(struct device *dev, size_t size, void *vaddr,
+ dma_addr_t dma_addr, unsigned long attrs);
+
#ifdef CONFIG_SWIOTLB
extern enum swiotlb_force swiotlb_force;
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 30ccbc08e229..126e9b3354d6 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -137,6 +137,11 @@ void *dma_direct_alloc(struct device *dev, size_t size,
void *ret;
int err;
+#ifdef CONFIG_SWIOTLB
+ if (unlikely(dev->dma_io_tlb_mem))
+ return swiotlb_alloc(dev, size, dma_handle, attrs);
+#endif
+
size = PAGE_ALIGN(size);
if (attrs & DMA_ATTR_NO_WARN)
gfp |= __GFP_NOWARN;
@@ -246,6 +251,13 @@ void dma_direct_free(struct device *dev, size_t size,
{
unsigned int page_order = get_order(size);
+#ifdef CONFIG_SWIOTLB
+ if (unlikely(dev->dma_io_tlb_mem)) {
+ swiotlb_free(dev, size, cpu_addr, dma_addr, attrs);
+ return;
+ }
+#endif
+
if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) &&
!force_dma_unencrypted(dev)) {
/* cpu_addr is a struct page cookie, not a kernel address */
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 1f05af09e61a..ca88ef59435d 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -459,14 +459,13 @@ static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr,
}
}
-phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t orig_addr,
- size_t mapping_size, size_t alloc_size,
- enum dma_data_direction dir, unsigned long attrs)
+static int swiotlb_tbl_find_free_region(struct device *hwdev,
+ dma_addr_t tbl_dma_addr,
+ size_t alloc_size,
+ unsigned long attrs)
{
struct io_tlb_mem *mem = get_io_tlb_mem(hwdev);
- dma_addr_t tbl_dma_addr = phys_to_dma_unencrypted(hwdev, mem->start);
unsigned long flags;
- phys_addr_t tlb_addr;
unsigned int nslots, stride, index, wrap;
int i;
unsigned long mask;
@@ -477,15 +476,6 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t orig_addr,
if (no_iotlb_memory && !hwdev->dma_io_tlb_mem)
panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");
- if (mem_encrypt_active())
- pr_warn_once("Memory encryption is active and system is using DMA bounce buffers\n");
-
- if (mapping_size > alloc_size) {
- dev_warn_once(hwdev, "Invalid sizes (mapping: %zd bytes, alloc: %zd bytes)",
- mapping_size, alloc_size);
- return (phys_addr_t)DMA_MAPPING_ERROR;
- }
-
mask = dma_get_seg_boundary(hwdev);
tbl_dma_addr &= mask;
@@ -547,7 +537,6 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t orig_addr,
mem->list[i] = 0;
for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE - 1) && mem->list[i]; i--)
mem->list[i] = ++count;
- tlb_addr = mem->start + (index << IO_TLB_SHIFT);
/*
* Update the indices to avoid searching in the next
@@ -570,45 +559,21 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t orig_addr,
if (!(attrs & DMA_ATTR_NO_WARN) && printk_ratelimit())
dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes), total %lu (slots), used %lu (slots)\n",
alloc_size, mem->nslabs, tmp_io_tlb_used);
- return (phys_addr_t)DMA_MAPPING_ERROR;
+ return -ENOMEM;
+
found:
mem->used += nslots;
spin_unlock_irqrestore(&mem->lock, flags);
- /*
- * Save away the mapping from the original address to the DMA address.
- * This is needed when we sync the memory. Then we sync the buffer if
- * needed.
- */
- for (i = 0; i < nslots; i++)
- mem->orig_addr[index+i] = orig_addr + (i << IO_TLB_SHIFT);
- if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
- (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
- swiotlb_bounce(orig_addr, tlb_addr, mapping_size, DMA_TO_DEVICE);
-
- return tlb_addr;
+ return index;
}
-/*
- * tlb_addr is the physical address of the bounce buffer to unmap.
- */
-void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
- size_t mapping_size, size_t alloc_size,
- enum dma_data_direction dir, unsigned long attrs)
+static void swiotlb_tbl_release_region(struct device *hwdev, int index,
+ size_t size)
{
struct io_tlb_mem *mem = get_io_tlb_mem(hwdev);
unsigned long flags;
- int i, count, nslots = ALIGN(alloc_size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
- int index = (tlb_addr - mem->start) >> IO_TLB_SHIFT;
- phys_addr_t orig_addr = mem->orig_addr[index];
-
- /*
- * First, sync the memory before unmapping the entry
- */
- if (orig_addr != INVALID_PHYS_ADDR &&
- !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
- ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
- swiotlb_bounce(orig_addr, tlb_addr, mapping_size, DMA_FROM_DEVICE);
+ int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
/*
* Return the buffer to the free list by setting the corresponding
@@ -640,6 +605,69 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
spin_unlock_irqrestore(&mem->lock, flags);
}
+phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t orig_addr,
+ size_t mapping_size, size_t alloc_size,
+ enum dma_data_direction dir, unsigned long attrs)
+{
+ struct io_tlb_mem *mem = get_io_tlb_mem(hwdev);
+ dma_addr_t tbl_dma_addr = phys_to_dma_unencrypted(hwdev, mem->start);
+ phys_addr_t tlb_addr;
+ unsigned int nslots, index;
+ int i;
+
+ if (mem_encrypt_active())
+ pr_warn_once("Memory encryption is active and system is using DMA bounce buffers\n");
+
+ if (mapping_size > alloc_size) {
+ dev_warn_once(hwdev, "Invalid sizes (mapping: %zd bytes, alloc: %zd bytes)",
+ mapping_size, alloc_size);
+ return (phys_addr_t)DMA_MAPPING_ERROR;
+ }
+
+ index = swiotlb_tbl_find_free_region(hwdev, tbl_dma_addr, alloc_size,
+ attrs);
+ if (index < 0)
+ return (phys_addr_t)DMA_MAPPING_ERROR;
+
+ tlb_addr = mem->start + (index << IO_TLB_SHIFT);
+
+ /*
+ * Save away the mapping from the original address to the DMA address.
+ * This is needed when we sync the memory. Then we sync the buffer if
+ * needed.
+ */
+ nslots = ALIGN(alloc_size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
+ for (i = 0; i < nslots; i++)
+ mem->orig_addr[index+i] = orig_addr + (i << IO_TLB_SHIFT);
+ if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
+ (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
+ swiotlb_bounce(orig_addr, tlb_addr, mapping_size, DMA_TO_DEVICE);
+
+ return tlb_addr;
+}
+
+/*
+ * tlb_addr is the physical address of the bounce buffer to unmap.
+ */
+void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
+ size_t mapping_size, size_t alloc_size,
+ enum dma_data_direction dir, unsigned long attrs)
+{
+ struct io_tlb_mem *mem = get_io_tlb_mem(hwdev);
+ int index = (tlb_addr - mem->start) >> IO_TLB_SHIFT;
+ phys_addr_t orig_addr = mem->orig_addr[index];
+
+ /*
+ * First, sync the memory before unmapping the entry
+ */
+ if (orig_addr != INVALID_PHYS_ADDR &&
+ !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
+ ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
+ swiotlb_bounce(orig_addr, tlb_addr, mapping_size, DMA_FROM_DEVICE);
+
+ swiotlb_tbl_release_region(hwdev, index, alloc_size);
+}
+
void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr,
size_t size, enum dma_data_direction dir,
enum dma_sync_target target)
@@ -706,6 +734,59 @@ dma_addr_t swiotlb_map(struct device *dev, phys_addr_t paddr, size_t size,
return dma_addr;
}
+void *swiotlb_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
+ unsigned long attrs)
+{
+ struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
+ int index;
+ void *vaddr;
+ phys_addr_t tlb_addr;
+
+ size = PAGE_ALIGN(size);
+ index = swiotlb_tbl_find_free_region(dev, mem->start, size, attrs);
+ if (index < 0)
+ return NULL;
+
+ tlb_addr = mem->start + (index << IO_TLB_SHIFT);
+ *dma_handle = phys_to_dma_unencrypted(dev, tlb_addr);
+
+ if (!dev_is_dma_coherent(dev)) {
+ unsigned long pfn = PFN_DOWN(tlb_addr);
+
+ /* remove any dirty cache lines on the kernel alias */
+ arch_dma_prep_coherent(pfn_to_page(pfn), size);
+
+ /* create a coherent mapping */
+ vaddr = dma_common_contiguous_remap(
+ pfn_to_page(pfn), size,
+ dma_pgprot(dev, PAGE_KERNEL, attrs),
+ __builtin_return_address(0));
+ if (!vaddr) {
+ swiotlb_tbl_release_region(dev, index, size);
+ return NULL;
+ }
+ } else {
+ vaddr = phys_to_virt(tlb_addr);
+ }
+
+ memset(vaddr, 0, size);
+
+ return vaddr;
+}
+
+void swiotlb_free(struct device *dev, size_t size, void *vaddr,
+ dma_addr_t dma_addr, unsigned long attrs)
+{
+ struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
+ unsigned int index;
+
+ if (!dev_is_dma_coherent(dev))
+ vunmap(vaddr);
+
+ index = (dma_addr - mem->start) >> IO_TLB_SHIFT;
+ swiotlb_tbl_release_region(dev, index, PAGE_ALIGN(size));
+}
+
size_t swiotlb_max_mapping_size(struct device *dev)
{
return ((size_t)1 << IO_TLB_SHIFT) * IO_TLB_SEGSIZE;
--
2.29.2.729.g45daf8777d-goog
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