Re: [PATCH 0/20] dma_ops for i386

Ingo Molnar
2008-03-26T13:04:17Z

* 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,