Re: [PATCH 0/20] dma_ops for i386

[Ingo Molnar <mingo@elte.hu>]

* Ingo Molnar <mingo@elte.hu> wrote:

> what i came up is the prototype 32-bit fix below - this works on 
> 32-bit but breaks 64-bit because we pass in physical addresses instead 
> of virtual direct addresses.
> 
> i'll fix the 64-bit side but that means materially touching all the 
> dma_mapping_ops instantiations materially on the 64-bit side - not 
> really something we wanted to do :-/

the full fix ended up being the one below. It's not that bad - and 
gart_64.c looks even a bit cleaner. Still, it needs careful review.

	Ingo

--------------->
Subject: x86: dma-ops on highmem fix
From: Ingo Molnar <mingo@elte.hu>

Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/kernel/pci-base_32.c    |    4 ++--
 arch/x86/kernel/pci-calgary_64.c |    3 ++-
 arch/x86/kernel/pci-dma_64.c     |    2 +-
 arch/x86/kernel/pci-gart_64.c    |   15 +++++++--------
 arch/x86/kernel/pci-nommu_64.c   |    4 ++--
 arch/x86/kernel/pci-swiotlb_64.c |    9 ++++++++-
 include/asm-x86/dma-mapping.h    |   10 ++++++----
 7 files changed, 28 insertions(+), 19 deletions(-)

Index: linux-x86.q/arch/x86/kernel/pci-base_32.c
===================================================================
--- linux-x86.q.orig/arch/x86/kernel/pci-base_32.c
+++ linux-x86.q/arch/x86/kernel/pci-base_32.c
@@ -4,12 +4,12 @@
 #include <linux/dma-mapping.h>
 #include <asm/dma-mapping.h>
 
-static dma_addr_t pci32_map_single(struct device *dev, void *ptr,
+static dma_addr_t pci32_map_single(struct device *dev, phys_addr_t ptr,
 				   size_t size, int direction)
 {
 	WARN_ON(size == 0);
 	flush_write_buffers();
-	return virt_to_phys(ptr);
+	return ptr;
 }
 
 static int pci32_dma_map_sg(struct device *dev, struct scatterlist *sglist,
Index: linux-x86.q/arch/x86/kernel/pci-calgary_64.c
===================================================================
--- linux-x86.q.orig/arch/x86/kernel/pci-calgary_64.c
+++ linux-x86.q/arch/x86/kernel/pci-calgary_64.c
@@ -470,10 +470,11 @@ error:
 	return 0;
 }
 
-static dma_addr_t calgary_map_single(struct device *dev, void *vaddr,
+static dma_addr_t calgary_map_single(struct device *dev, phys_addr_t paddr,
 	size_t size, int direction)
 {
 	dma_addr_t dma_handle = bad_dma_address;
+	void *vaddr = phys_to_virt(paddr);
 	unsigned long uaddr;
 	unsigned int npages;
 	struct iommu_table *tbl = find_iommu_table(dev);
Index: linux-x86.q/arch/x86/kernel/pci-dma_64.c
===================================================================
--- linux-x86.q.orig/arch/x86/kernel/pci-dma_64.c
+++ linux-x86.q/arch/x86/kernel/pci-dma_64.c
@@ -141,7 +141,7 @@ dma_alloc_coherent(struct device *dev, s
 	}
 
 	if (dma_ops->map_simple) {
-		*dma_handle = dma_ops->map_simple(dev, memory,
+		*dma_handle = dma_ops->map_simple(dev, virt_to_phys(memory),
 					      size,
 					      PCI_DMA_BIDIRECTIONAL);
 		if (*dma_handle != bad_dma_address)
Index: linux-x86.q/arch/x86/kernel/pci-gart_64.c
===================================================================
--- linux-x86.q.orig/arch/x86/kernel/pci-gart_64.c
+++ linux-x86.q/arch/x86/kernel/pci-gart_64.c
@@ -264,9 +264,9 @@ static dma_addr_t dma_map_area(struct de
 }
 
 static dma_addr_t
-gart_map_simple(struct device *dev, char *buf, size_t size, int dir)
+gart_map_simple(struct device *dev, phys_addr_t paddr, size_t size, int dir)
 {
-	dma_addr_t map = dma_map_area(dev, virt_to_bus(buf), size, dir);
+	dma_addr_t map = dma_map_area(dev, paddr, size, dir);
 
 	flush_gart();
 
@@ -275,18 +275,17 @@ gart_map_simple(struct device *dev, char
 
 /* Map a single area into the IOMMU */
 static dma_addr_t
-gart_map_single(struct device *dev, void *addr, size_t size, int dir)
+gart_map_single(struct device *dev, phys_addr_t paddr, size_t size, int dir)
 {
-	unsigned long phys_mem, bus;
+	unsigned long bus;
 
 	if (!dev)
 		dev = &fallback_dev;
 
-	phys_mem = virt_to_phys(addr);
-	if (!need_iommu(dev, phys_mem, size))
-		return phys_mem;
+	if (!need_iommu(dev, paddr, size))
+		return paddr;
 
-	bus = gart_map_simple(dev, addr, size, dir);
+	bus = gart_map_simple(dev, paddr, size, dir);
 
 	return bus;
 }
Index: linux-x86.q/arch/x86/kernel/pci-nommu_64.c
===================================================================
--- linux-x86.q.orig/arch/x86/kernel/pci-nommu_64.c
+++ linux-x86.q/arch/x86/kernel/pci-nommu_64.c
@@ -26,10 +26,10 @@ check_addr(char *name, struct device *hw
 }
 
 static dma_addr_t
-nommu_map_single(struct device *hwdev, void *ptr, size_t size,
+nommu_map_single(struct device *hwdev, phys_addr_t paddr, size_t size,
 	       int direction)
 {
-	dma_addr_t bus = virt_to_bus(ptr);
+	dma_addr_t bus = paddr;
 	if (!check_addr("map_single", hwdev, bus, size))
 				return bad_dma_address;
 	return bus;
Index: linux-x86.q/arch/x86/kernel/pci-swiotlb_64.c
===================================================================
--- linux-x86.q.orig/arch/x86/kernel/pci-swiotlb_64.c
+++ linux-x86.q/arch/x86/kernel/pci-swiotlb_64.c
@@ -11,11 +11,18 @@
 
 int swiotlb __read_mostly;
 
+static dma_addr_t
+swiotlb_map_single_phys(struct device *hwdev, phys_addr_t paddr, size_t size,
+			int direction)
+{
+	return swiotlb_map_single(hwdev, phys_to_virt(paddr), size, direction);
+}
+
 const struct dma_mapping_ops swiotlb_dma_ops = {
 	.mapping_error = swiotlb_dma_mapping_error,
 	.alloc_coherent = swiotlb_alloc_coherent,
 	.free_coherent = swiotlb_free_coherent,
-	.map_single = swiotlb_map_single,
+	.map_single = swiotlb_map_single_phys,
 	.unmap_single = swiotlb_unmap_single,
 	.sync_single_for_cpu = swiotlb_sync_single_for_cpu,
 	.sync_single_for_device = swiotlb_sync_single_for_device,
Index: linux-x86.q/include/asm-x86/dma-mapping.h
===================================================================
--- linux-x86.q.orig/include/asm-x86/dma-mapping.h
+++ linux-x86.q/include/asm-x86/dma-mapping.h
@@ -16,10 +16,10 @@ struct dma_mapping_ops {
 				dma_addr_t *dma_handle, gfp_t gfp);
 	void            (*free_coherent)(struct device *dev, size_t size,
 				void *vaddr, dma_addr_t dma_handle);
-	dma_addr_t      (*map_single)(struct device *hwdev, void *ptr,
+	dma_addr_t      (*map_single)(struct device *hwdev, phys_addr_t ptr,
 				size_t size, int direction);
 	/* like map_single, but doesn't check the device mask */
-	dma_addr_t      (*map_simple)(struct device *hwdev, char *ptr,
+	dma_addr_t      (*map_simple)(struct device *hwdev, phys_addr_t ptr,
 				size_t size, int direction);
 	void            (*unmap_single)(struct device *dev, dma_addr_t addr,
 				size_t size, int direction);
@@ -73,7 +73,7 @@ dma_map_single(struct device *hwdev, voi
 	       int direction)
 {
 	BUG_ON(!valid_dma_direction(direction));
-	return dma_ops->map_single(hwdev, ptr, size, direction);
+	return dma_ops->map_single(hwdev, virt_to_phys(ptr), size, direction);
 }
 
 static inline void
@@ -174,7 +174,9 @@ static inline dma_addr_t dma_map_page(st
 				      size_t offset, size_t size,
 				      int direction)
 {
-	return dma_map_single(dev, page_address(page)+offset, size, direction);
+	BUG_ON(!valid_dma_direction(direction));
+	return dma_ops->map_single(dev, page_to_phys(page)+offset,
+				   size, direction);
 }
 
 static inline void dma_unmap_page(struct device *dev, dma_addr_t addr,