dma-debug: refactor to use physical addresses for page mapping

Convert the DMA debug infrastructure from page-based to physical address-based
mapping as a preparation to rely on physical address for DMA mapping routines.

The refactoring renames debug_dma_map_page() to debug_dma_map_phys() and
changes its signature to accept a phys_addr_t parameter instead of struct page
and offset. Similarly, debug_dma_unmap_page() becomes debug_dma_unmap_phys().
A new dma_debug_phy type is introduced to distinguish physical address mappings
from other debug entry types. All callers throughout the codebase are updated
to pass physical addresses directly, eliminating the need for page-to-physical
conversion in the debug layer.

This refactoring eliminates the need to convert between page pointers and
physical addresses in the debug layer, making the code more efficient and
consistent with the DMA mapping API's physical address focus.

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
[mszyprow: added a fixup]
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/56d1a6769b68dfcbf8b26a75a7329aeb8e3c3b6a.1757423202.git.leonro@nvidia.com
Link: https://lore.kernel.org/all/20250910052618.GH341237@unreal/

1 files changed, 20 insertions, 19 deletions

diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c
index b82399437db0..b275db9ca6a0 100644
--- a/kernel/dma/debug.c
+++ b/kernel/dma/debug.c
@@ -40,6 +40,7 @@ enum {
 	dma_debug_coherent,
 	dma_debug_resource,
 	dma_debug_noncoherent,
+	dma_debug_phy,
 };
 
 enum map_err_types {
@@ -143,6 +144,7 @@ static const char *type2name[] = {
 	[dma_debug_coherent] = "coherent",
 	[dma_debug_resource] = "resource",
 	[dma_debug_noncoherent] = "noncoherent",
+	[dma_debug_phy] = "phy",
 };
 
 static const char *dir2name[] = {
@@ -1054,17 +1056,16 @@ static void check_unmap(struct dma_debug_entry *ref)
 	dma_entry_free(entry);
 }
 
-static void check_for_stack(struct device *dev,
-			    struct page *page, size_t offset)
+static void check_for_stack(struct device *dev, phys_addr_t phys)
 {
 	void *addr;
 	struct vm_struct *stack_vm_area = task_stack_vm_area(current);
 
 	if (!stack_vm_area) {
 		/* Stack is direct-mapped. */
-		if (PageHighMem(page))
+		if (PhysHighMem(phys))
 			return;
-		addr = page_address(page) + offset;
+		addr = phys_to_virt(phys);
 		if (object_is_on_stack(addr))
 			err_printk(dev, NULL, "device driver maps memory from stack [addr=%p]\n", addr);
 	} else {
@@ -1072,10 +1073,12 @@ static void check_for_stack(struct device *dev,
 		int i;
 
 		for (i = 0; i < stack_vm_area->nr_pages; i++) {
-			if (page != stack_vm_area->pages[i])
+			if (__phys_to_pfn(phys) !=
+			    page_to_pfn(stack_vm_area->pages[i]))
 				continue;
 
-			addr = (u8 *)current->stack + i * PAGE_SIZE + offset;
+			addr = (u8 *)current->stack + i * PAGE_SIZE +
+			       (phys % PAGE_SIZE);
 			err_printk(dev, NULL, "device driver maps memory from stack [probable addr=%p]\n", addr);
 			break;
 		}
@@ -1204,9 +1207,8 @@ void debug_dma_map_single(struct device *dev, const void *addr,
 }
 EXPORT_SYMBOL(debug_dma_map_single);
 
-void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
-			size_t size, int direction, dma_addr_t dma_addr,
-			unsigned long attrs)
+void debug_dma_map_phys(struct device *dev, phys_addr_t phys, size_t size,
+		int direction, dma_addr_t dma_addr, unsigned long attrs)
 {
 	struct dma_debug_entry *entry;
 
@@ -1221,19 +1223,18 @@ void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
 		return;
 
 	entry->dev       = dev;
-	entry->type      = dma_debug_single;
-	entry->paddr	 = page_to_phys(page) + offset;
+	entry->type      = dma_debug_phy;
+	entry->paddr	 = phys;
 	entry->dev_addr  = dma_addr;
 	entry->size      = size;
 	entry->direction = direction;
 	entry->map_err_type = MAP_ERR_NOT_CHECKED;
 
-	check_for_stack(dev, page, offset);
+	if (!(attrs & DMA_ATTR_MMIO)) {
+		check_for_stack(dev, phys);
 
-	if (!PageHighMem(page)) {
-		void *addr = page_address(page) + offset;
-
-		check_for_illegal_area(dev, addr, size);
+		if (!PhysHighMem(phys))
+			check_for_illegal_area(dev, phys_to_virt(phys), size);
 	}
 
 	add_dma_entry(entry, attrs);
@@ -1277,11 +1278,11 @@ void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
 }
 EXPORT_SYMBOL(debug_dma_mapping_error);
 
-void debug_dma_unmap_page(struct device *dev, dma_addr_t dma_addr,
+void debug_dma_unmap_phys(struct device *dev, dma_addr_t dma_addr,
 			  size_t size, int direction)
 {
 	struct dma_debug_entry ref = {
-		.type           = dma_debug_single,
+		.type           = dma_debug_phy,
 		.dev            = dev,
 		.dev_addr       = dma_addr,
 		.size           = size,
@@ -1305,7 +1306,7 @@ void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
 		return;
 
 	for_each_sg(sg, s, nents, i) {
-		check_for_stack(dev, sg_page(s), s->offset);
+		check_for_stack(dev, sg_phys(s));
 		if (!PageHighMem(sg_page(s)))
 			check_for_illegal_area(dev, sg_virt(s), s->length);
 	}