highmem pci dma mapping does not work, missing cast in asm-i386/pci.h

highmem pci dma mapping does not work, missing cast in asm-i386/pci.h

Post by Benjamin LaHais » Wed, 12 Jun 2002 09:00:11



Hello all,

There's a missing cast in pci_map_page that causes 64 bit capable
drivers to access the wrong memory for highmem pages.  Please
include the patch below to fix it.

                -ben
--
"You will be reincarnated as a toad; and you will be much happier."

:r ~/patches/v2.4/v2.4.19-pre10-pci_highmem.diff
diff -urN v2.4.19-pre10/include/asm-i386/pci.h pci-v2.4.19-pre10/include/asm-i386/pci.h
--- v2.4.19-pre10/include/asm-i386/pci.h        Thu Jun  6 20:10:08 2002

        if (direction == PCI_DMA_NONE)
                out_of_line_bug();

-       return (page - mem_map) * PAGE_SIZE + offset;
+       return (dma_addr_t)(page - mem_map) * PAGE_SIZE + offset;
 }

 static inline void pci_unmap_page(struct pci_dev *hwdev, dma_addr_t dma_address,
-
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highmem pci dma mapping does not work, missing cast in asm-i386/pci.h

Post by Jes Sorense » Tue, 25 Jun 2002 00:50:04


Ben> Hello all, There's a missing cast in pci_map_page that causes 64
Ben> bit capable drivers to access the wrong memory for highmem pages.
Ben> Please include the patch below to fix it.

Looking at this one, I believe we need to do the same for
page_to_phys() - either by using dma_addr_t as the type or explicitly
going u64 #ifdef CONFIG_HIGHMEM.

Patch using dma_addr_t included relative to 2.4.18.

Btw. I noticed that in 2.5.24/ia32 we use CONFIG_HIGHMEM to declare
dma_addr_t as 64 bit but CONFIG_HIGHMEM64G to handle page_to_phys. Is
this just an oversight or on purpose?

Comments?

Jes

--- include/asm-i386/io.h~      Sun Jun 23 11:29:26 2002

 #define _ASM_IO_H

 #include <linux/config.h>
+#include <asm/types.h>

 /*

 /*
  * Change "struct page" to physical address.
  */
-#define page_to_phys(page)     ((page - mem_map) << PAGE_SHIFT)
+#define page_to_phys(page)     ((dma_addr_t)(page - mem_map) << PAGE_SHIFT)

 extern void * __ioremap(unsigned long offset, unsigned long size, unsigned long flags);

-
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